[Federal Register Volume 77, Number 163 (Wednesday, August 22, 2012)]
[Proposed Rules]
[Pages 50767-50854]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-19659]
[[Page 50767]]
Vol. 77
Wednesday,
No. 163
August 22, 2012
Part II
Department of the Interior
Fish and Wildlife Service
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50 CFR Part 17
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Endangered and Threatened Wildlife and Plants; Endangered Status for
Four Central Texas Salamanders and Designation of Critical Habitat;
Proposed Rule
Federal Register / Vol. 77 , No. 163 / Wednesday, August 22, 2012 /
Proposed Rules
[[Page 50768]]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2012-0035; 4500030114]
RIN 1018-AY22
Endangered and Threatened Wildlife and Plants; Endangered Status
for Four Central Texas Salamanders and Designation of Critical Habitat
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
list the Austin blind salamander, Jollyville Plateau salamander,
Georgetown salamander, and Salado salamander as endangered under the
Endangered Species Act of 1973, as amended (Act), and propose to
designate critical habitat for the species. In total, we propose to
designate approximately 5,983 acres (2,440 hectares) as critical
habitat for the four species. The proposed critical habitat is located
in Travis, Williamson, and Bell Counties, Texas.
DATES: We will accept comments received or postmarked on or before
October 22, 2012. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES section, below) must be received by
11:59 p.m. Eastern Time on the closing date. We must receive requests
for public hearings, in writing, at the address shown in the FOR
FURTHER INFORMATION CONTACT section by October 9, 2012.
Public Informational Sessions and Public Hearings: We will hold two
public informational sessions and two public hearings on this proposed
rule. We will hold a public informational session from 5:30 p.m. to
6:30 p.m., followed by a public hearing from 7 p.m. to 8:30 p.m., in
Round Rock, Texas, on Wednesday, September 5 (see ADDRESSES). We will
hold a public informational session from 6:30 p.m. to 7:30 p.m.,
followed by a public hearing from 8 p.m. to 9:30 p.m., in Austin,
Texas, on Thursday, September 6 (see ADDRESSES). Registration to
present oral comments on the proposed rule at the public hearings will
begin at the start of each informational session.
ADDRESSES: Document availability: You may obtain copies of the proposed
rule on the Internet at http://www.regulations.gov at Docket No. FWS-
R2-ES-2012-0035 or by mail from the Austin Ecological Services Field
Office (see FOR FURTHER INFORMATION CONTACT).
The coordinates or plot points or both from which the maps are
generated are included in the administrative record for this critical
habitat designation and are available at (http://www.fws.gov/southwest/es/AustinTexas/), http://regulations.gov at Docket No. FWS-R2-ES-2012-
0035, and at the Austin Ecological Services Field Office (see FOR
FURTHER INFROMATION CONTACT). Any additional tools or supporting
information that we may develop for this critical habitat designation
will also be available at the above locations.
Written Comments: You may submit written comments by one of the
following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. Search for Docket No. FWS-R2-ES-2012-0035. You may
submit a comment by clicking on ``Comment Now!''
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R2-ES-2012-0035ES-2012-0035; Division of
Policy and Directives Management; U.S. Fish and Wildlife Service; 4401
N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.
We request that you send comments only by the methods described
above. We will post all comments on http://www.regulations.gov. This
generally means that we will post any personal information you provide
us (see the Information Requested section below for more information).
Public informational sessions and public hearings: The September 5,
2012, public informational session and hearing will be held at the
Wingate by Wyndham Round Rock, 1209 N. IH 35 North, Exit 253 at Hwy 79,
Round Rock, Texas 78664. The September 6, 2012, public informational
session and hearing will be held at Thompson Conference Center, 2405
Robert Dedman Drive, Room 2.102, Austin, Texas 78705. People needing
reasonable accommodations in order to attend and participate in the
public hearings should contact Adam Zerrenner, Field Supervisor, Austin
Ecological Services Field Office, as soon as possible (see FOR FURTHER
INFORMATION CONTACT).
FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor, U.S.
Fish and Wildlife Service, Austin Ecological Services Field Office,
10711 Burnet Rd, Suite 200, Austin, TX 78758; by telephone 512-490-
0057; or by facsimile 512-490-0974. Persons who use a
telecommunications device for the deaf (TDD) may call the Federal
Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why We Need to Publish a Rule
This is a proposed rule to list the Austin blind salamander
(Eurycea waterlooensis), Jollyville Plateau salamander (Eurycea
tonkawae), Georgetown salamander (Eurycea naufragia), and Salado
salamander (Eurycea chisholmensis) as endangered.
With this rule, we are proposing to designate the following
critical habitat for the four central Texas salamanders:
Austin Blind salamander: 120 acres (49 hectares)
Jollyville Plateau salamander: 4,460 acres (1,816
hectares)
Georgetown salamander: 1,031 acres (423 hectares)
Salado salamander: 372 acres (152 hectares)
The proposed critical habitat is located within Travis, Williamson,
and Bell Counties, Texas.
The Basis for Our Action
Under the Endangered Species Act, we can determine that a species
is endangered or threatened based on any of the following five factors:
(A) Destruction, modification, or curtailment of its habitat or range;
(B) overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) inadequacy of
existing regulatory mechanisms; or (E) other natural or manmade factors
affecting the species continued existence. Based on our analysis under
the five factors, we find that the four central Texas salamanders are
primarily threatened by: factors A and D. Therefore, these species
qualify for listing, which can only be done by issuing a rule.
The Act requires that the Secretary designate critical habitat for
a species, to the maximum extent prudent and determinable, concurrently
with making a determination that a species is an endangered or
threatened species. Section 4(b)(2) of the Act requires that the
Secretary designate critical habitat based upon the best scientific
data available, and after taking into consideration the economic
impact, the impact on national security, and any other relevant impact
of specifying any particular area as critical habitat. Section 4(b)(2)
of the Act provides that the Secretary may exclude any area from
critical habitat if he determines that the benefits of excluding that
area outweigh the benefits of including it in the
[[Page 50769]]
designation, unless such an exclusion would result in the extinction of
the species. This ``weighing'' of considerations under section 4(b)(2)
of the Act is the next step in the designation process, in which the
Secretary may consider particular areas for exclusion from the final
designation.
We are preparing an economic analysis. To ensure that we consider
the economic impacts, we are preparing a draft economic analysis of the
proposed critical habitat designations. We will use information from
this analysis to inform the development of our final designation of
critical habitat for these species.
We will seek peer review. We are seeking comments from independent
specialists to ensure that our critical habitat designations are based
on scientifically sound data, assumptions, and analyses. We have
invited these peer reviewers to comment on our specific assumptions and
conclusions in these proposed critical habitat designations. Because we
will consider all comments and information we receive during the
comment period, our final determinations may differ from this proposal.
Information Requested
We intend that any final action resulting from this proposed rule
will be based on the best scientific and commercial data available and
be as accurate and as effective as possible. Therefore, we request
comments or information from other concerned governmental agencies,
Native American tribes, the scientific community, industry, or any
other interested parties concerning this proposed rule. We particularly
seek comments concerning:
(1) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to these species and regulations that may
be addressing those threats.
(2) Additional information concerning the historical and current
status, range, distribution, and population size of these species,
including the locations of any additional populations of these species.
(3) Any information on the biological or ecological requirements of
these species, and ongoing conservation measures for these species and
their habitats.
(4) Current or planned activities in the areas occupied by the
species and possible impacts of these activities on these species.
(5) The reasons why we should or should not designate habitat as
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et
seq.) including whether there are threats to the species from human
activity, the degree of which can be expected to increase due to the
designation, and whether that increase in threat outweighs the benefit
of designation, such that the designation of critical habitat may not
be prudent.
(6) Specific information on:
(a) The amount and distribution of the four central Texas
salamanders' habitats,
(b) What areas, that are currently occupied by these species, that
contain features essential to their conservation,
(c) Special management considerations or protection that may be
needed in critical habitat areas we are proposing, including managing
for the potential effects of climate change,
(d) What areas not occupied at the time of listing are essential
for the conservation of these species and why,
(e) How subterranean populations of these four salamander species
are distributed underground, and
(f) The interconnectedness of salamander habitats in terms of
hydrology, and whether salamanders are able to move between sites
through underground aquifer conduits.
(7) Land use designations and current or planned activities in the
subject areas and their possible impacts on the four central Texas
salamanders and on proposed critical habitat.
(8) Information on the projected and reasonably likely impacts of
climate change on the four central Texas salamanders and proposed
critical habitat.
(9) Any probable economic, national security, or other relevant
impacts of designating any area that may be included in the final
critical habitat designation; in particular, we seek information on any
impacts on small entities or families, and the benefits of including or
excluding areas that exhibit these impacts.
(10) Whether any specific areas we are proposing for critical
habitat designation should be considered for exclusion under section
4(b)(2) of the Act, and whether the benefits of potentially excluding
any specific area outweigh the benefits of including that area under
section 4(b)(2) of the Act; for example, areas that have a 10(a)(1)(B)
permit and habitat conservation plan (HCP) that covers any of these
salamanders may be considered for exclusion (potentially including the
Four Points HCP that covers Jollyville Plateau salamanders).
(11) Whether we could improve or modify our approach to designating
critical habitat in any way to provide for greater public participation
and understanding, or to better accommodate public concerns and
comments.
Please note that submissions merely stating support for or
opposition to the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or
threatenedspecies must be made ``solely on the basis of the best
scientific and commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in the ADDRESSES section. We request
that you send comments only by the methods described in the ADDRESSES
section.
If you submit information via http://www.regulations.gov, your
entire submission--including any personal identifying information--will
be posted on the Web site. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on http://www.regulations.gov.
Please include sufficient information with your comments to allow us to
verify any scientific or commercial information you include.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on http://www.regulations.gov, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, Austin Ecological Services Field Office (see FOR
FURTHER INFORMATION CONTACT).
Previous Federal Actions
The Austin blind and Salado salamanders were included in nine
Candidate Notices of Review (67 FR 40657, June 13, 2002; 69 FR 24876,
May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756, September 12,
2006; 72 FR 69034, December 6, 2007; 73 FR 75176, December 10, 2008; 74
FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR
66370, October 26, 2011). The listing priority number has remained at 2
throughout the reviews for both species, indicating that threats to the
species were both imminent and high in magnitude. In addition, on May
11, 2004, the Service received a petition from the Center for
Biological Diversity to list 225 species we previously had identified
as
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candidates for listing in accordance with section 4 of the Act,
including the Austin blind and Salado salamanders.
The Jollyville Plateau salamander was petitioned to be listed as an
endangered species on June 13, 2005, by Save Our Springs Alliance.
Action on this petition was precluded by court orders and settlement
agreements for other listing actions until 2006. On February 13, 2007,
we published a 90-day petition finding (72 FR 6699) in which we
concluded that the petition presented substantial information
indicating that listing may be warranted. On December 13, 2007, we
published the 12-month finding (72 FR 71040) on the Jollyville Plateau
salamander, which concluded that listing was warranted, but precluded
by higher priority actions. The Jollyville Plateau salamander was
subsequently included in all of our annual Candidate Notices of Review
(73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR
69222, November 10, 2010; 76 FR 66370, October 26, 2011). Throughout
the three reviews, the listing priority number has remained at 8,
indicating that threats to the species were imminent, but moderate to
low in magnitude. On September 30, 2010, the Jollyville Plateau
salamander was petitioned to be emergency listed by Save Our Springs
Alliance and Center for Biological Diversity. We issued a petition
response letter to Save Our Springs Alliance and Center for Biological
Diversity on December 1, 2011, which stated that emergency listing a
species is not a petitionable action under the Administrative Procedure
Act or the Act; therefore, we treat a petition requesting emergency
listing solely as a petition to list a species under the Act.
The Georgetown salamander was included in 10 Candidate Notices of
Review (66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002; 69
FR 24876, May 4, 2004; 70 FR 24870, May 11, 2005; 71 FR 53756,
September 12, 2006; 72 FR 69034, December 6, 2007; 73 FR 75176,
December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November
10, 2010; 76 FR 66370, October 26, 2011). In the 2008 review, the
listing priority number was lowered from 2 to 8, indicating that
threats to the species were imminent, but moderate to low in magnitude.
This reduction in listing priority number was primarily due to the land
acquisition and conservation efforts of the Williamson County
Conservation Foundation. In addition, the Georgetown salamander was
petitioned by the Center for Biological Diversity to be listed as an
endangered species on May 11, 2004, but at that time, it was already a
candidate species whose listing was precluded by higher priority
actions.
Endangered Status for the Four Central Texas Salamanders
Background
It is our intent to discuss below only those topics directly
relevant to the proposed listing of the Austin blind salamander,
Jollyville Plateau salamander, Georgetown salamander, and Salado
salamander as endangered in this section of the proposed rule.
Species Information
All four central Texas salamanders (Austin blind, Jollyville
Plateau, Georgetown, and Salado salamanders) are neotenic (do not
transform into a terrestrial form) members of the family
Plethodontidae. Plethodontid salamanders comprise the largest family of
salamanders within the Order Caudata, and are characterized by an
absence of lungs (Petranka 1998, pp. 157-158). As neotenic salamanders,
they retain external feathery gills and inhabit aquatic habitats
(springs, spring-runs, and wet caves) throughout their lives
(Chippindale et al. 2000, p. 1). In other words, all four of these
salamanders are entirely aquatic and respirate through gills. Also, all
adult salamanders of these four species are about 2 inches (in) (5
centimeters (cm)) long (Chippindale et al. 2000, pp. 32-42; Hillis et
al. 2001, p. 268).
Each species inhabits water of high quality with a narrow range of
conditions (for example, temperature, pH, and alkalinity) maintained by
the Edwards Aquifer. All four species depend on this water from the
Edwards Aquifer in sufficient quantity and quality to meet their life-
history requirements for survival, growth, and reproduction. The
Edwards Aquifer is a karst aquifer characterized by open chambers such
as caves, fractures, and other cavities that were formed either
directly or indirectly by dissolution of subsurface rock formations.
Water for the salamanders is provided by infiltration of surface water
through the soil or recharge features (caves, faults, fractures,
sinkholes, or other open cavities) into the Edwards Aquifer, which
discharges from springs as groundwater (Schram 1995, p. 91). The
habitat of one species (Austin blind salamander) occurs in the Barton
Springs Segment of the Edwards Aquifer, while the habitats of the three
other species occur in the Northern Segment of the Edwards Aquifer. The
recharge and contributing zones of these segments of the Edwards
Aquifer are found in portions of Travis, Williamson, Blanco, Bell,
Burnet, Lampasas, Mills, Hays, Coryell, and Hamilton Counties, Texas
(Hill Country Foundation 1995, p. 1). The three salamander species that
occur in the Northern Segment of the Edwards Aquifer (Jollyville
Plateau, Georgetown, and Salado salamanders) have very similar external
morphology. Because of this, they were previously believed to be the
same species; however, molecular evidence strongly indicates that there
is a high level of divergence between the three groups (Chippindale et
al. 2000, pp. 15-16).
The four central Texas salamander species spend varying portions of
their life within their surface (in or near spring openings and pools
as well as spring runs) and subsurface (within caves or other
underground areas within the Edwards Aquifer) habitats. They travel an
unknown depth into interstitial spaces (empty voids between rocks)
within the spring or streambed substrate that provide foraging habitat
and protection from predators and drought conditions (Cole 1995, p. 24;
Pierce and Wall 2011, pp. 16-17). They may also use deeper passages of
the aquifer that connect to the spring opening (Dries 2011, City of
Austin (COA), pers. comm.). This behavior makes it difficult to
accurately estimate population sizes, as only salamanders on the
surface can be regularly monitored. Therefore, the status of subsurface
populations is largely unknown, making it difficult to assess the
effects of threats on the subsurface populations and their habitat.
The Austin blind, Jollyville Plateau, Georgetown, and Salado
salamanders have much in common. All four species are entirely aquatic
throughout each portion of their life cycles and highly dependent on
water from the Edwards Aquifer in sufficient quantity and quality to
meet their life-history requirements for growth, survival, and
reproduction. Although detailed dietary studies are lacking for these
four salamander species, their diets are presumed to be similar to
other Eurycea species, consisting of small aquatic invertebrates such
as amphipods, copepods, isopods, and insect larvae [reviewed in COA
2001, pp. 5-6]. The four central Texas salamanders also share similar
predators, which include centrarchid fish (carnivorous freshwater fish
belonging to the sunfish family), crayfish, and large aquatic insects
(Pierce and Wall 2011, pp. 18-20; Bowles et al. 2006, p. 117; Cole
1995, p. 26). Because eggs are very rarely found on the surface, it is
believed that these salamanders deposit their eggs underground for
protection (O'Donnell et al. 2005, p. 18). The detection of
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juveniles in all seasons suggests that reproduction occurs year-round
(Bendik 2011a, p. 26; Hillis et al. 2001, p. 273).
Dispersal patterns through streams or aquifers for these four
salamander species are relatively unknown. However, one study of other
closely related Eurycea species in the southeastern portion of central
Texas found that populations of salamanders are genetically isolated
from one another and neither aquifers nor streams serve as dispersal
corridors (Lucas et al. 2009, pp. 1,315-1,316).
On the other hand, some evidence suggests that the four Texas
salamanders may be able to travel some distance through subsurface
aquifer conduits. Recent genetic work on the Jollyville Plateau
salamander showed evidence of gene flow between sites that are not
connected by surface flow (Chippindale 2010, pp. 9, 18-22). This study
suggests that central Texas salamanders are regionally isolated, but
populations within those regions have some level of dispersal ability
through the subsurface habitat. For example, the Austin blind
salamander is believed to occur underground throughout the entire
Barton Springs complex (Dries 2011, pers. comm.). The spring habitats
used by salamanders of the Barton Springs complex are not connected on
the surface, so the Austin blind salamander population extends at least
984 feet (ft) (300 meters (m)) underground, as this is the approximate
distance between the farthest two outlets within the Barton Springs
complex known to be occupied by the species.
Due to the similar life history of the other three Eurycea species
considered here, it is plausible that populations of these species
could also extend this distance through subterranean habitat. Dye-trace
studies have demonstrated that some Jollyville Plateau salamander sites
located miles apart are connected hydrologically (Hauwert and Warton
1997), but it remains unclear if salamanders are able to travel between
those sites. Also, in Salado, a large underground conduit conveys
groundwater from the area under the Stagecoach Hotel to Big Boiling
Spring (Mahler 2012, U.S. Geological Survey, pers. comm.).
Additionally, in Barton Springs, a mark and recapture study failed to
document the movement of endangered Barton Springs salamanders (Eurycea
sosorum) between any of the springs in the Barton Springs complex
(Dries 2012, pers. comm.), although this study has only recently begun
and is relatively small in scope. In conclusion, there is some evidence
that populations could be connected through subterranean habitat,
although dispersal patterns and the actual nature of connectivity are
largely unknown.
Because the hydrology of central Texas is very complex and
information on the hydrology of specific spring sites is largely
unknown, we are seeking information on spring hydrology and salamander
dispersal during the public comment period (see ``Information
Requested'' above).
Each species is discussed in more detail below.
Austin Blind Salamander
The Austin blind salamander has a pronounced extension of the
snout, no external eyes, and weakly developed tail fins. In general
appearance and coloration, the Austin blind salamander is more similar
to the Texas blind salamander (Eurycea rathbuni) that occurs in the
Southern Segment of the Edwards Aquifer than its sympatric (occurring
within the same range) species, the Barton Springs salamander. The
Austin blind salamander has a reflective, lightly pigmented skin with a
pearly white or lavender appearance (Hillis et al. 2001, p. 271).
Before the Austin blind salamander was formally described, juvenile
salamanders were sighted occasionally in Barton Springs, and thought to
be a variation of the Barton Springs salamander. It was not until 2001,
that enough specimens were available to formally describe these
juveniles as a separate species using morphological and genetic
characteristics (Hillis et al. 2001, p. 267). Given the reduced eye
structure of the Austin blind salamander, and the fact that it is
rarely seen at the water's surface (Hillis et al. 2001, p. 267), this
salamander is thought to be more subterranean than the surface-dwelling
Barton Springs salamander.
The Austin blind salamander occurs in Barton Springs in Austin,
Texas. These springs are fed by the Barton Springs Segment of the
Edwards Aquifer. This segment covers roughly 155 square miles (mi) (401
square kilometers (km)) from southern Travis County to northern Hays
County, Texas (Smith and Hunt 2004, p. 7). It has a storage capacity of
over 300,000 acre-feet. The contributing zone for the Barton Springs
Segment of the Edwards Aquifer that supplies water to the salamander's
spring habitat extends into Travis, Blanco, and Hays Counties, Texas
(Ross 2011, p. 3).
The Austin blind salamander is found in three of the four Barton
Springs outlets in the City of Austin's Zilker Park, Travis County,
Texas: Main (Parthenia) Springs, Eliza Springs, and Sunken Garden (Old
Mill or Zenobia) Springs. The Main Springs provides water for the
Barton Springs Pool, and is operated by the City of Austin as a public
swimming pool. These spring sites have been significantly modified for
human use. The area around Main Springs was impounded in the late 1920s
to create Barton Springs Pool. Flows from Eliza and Sunken Garden
Springs are also retained by concrete structures, forming small pools
on either side of Barton Springs Pool (COA 1998, p. 6; Service 2005, p.
1.6-25). The Austin blind salamander has not been observed at the
fourth Barton Springs outlet, known as Upper Barton Springs (Hillis et
al. 2001, p. 273). For more information on habitat, see the ``Proposed
Critical Habitat Designation for the Four Central Texas Salamanders''
section of this proposed rule.
From January 1998 to December 2000, there were only 17 documented
observations of the Austin blind salamander. During this same time-
frame, 1,518 Barton Springs salamander observations were made (Hillis
et al. 2001, p. 273). The abundance of Austin blind salamanders
increased slightly from 2002-2006, but fewer observations have been
made in more recent years (2009-2010) (COA 2011a, pp. 51-52). When they
are observed, Austin blind salamanders occur in relatively low numbers
(COA 2011a, pp. 51-52). Most of the Austin blind salamanders that were
observed during these surveys were juveniles (less than 1 in (2.5 cm)
in total length) (Hillis et al. 2001, p. 273). Although the technology
to safely and reliably mark salamanders for individual recognition has
recently been developed (O'Donnell et al. 2008, p. 3), population
estimates for this species have not been undertaken, because surveying
within the Edwards Aquifer is not possible at the current time.
However, population estimates are possible for aquifer-dwelling species
using genetic techniques, and one such study is planned for the Austin
blind salamander in the near future (Texas Parks and Wildlife
Department (TPWD) 2011a, p. 11).
Jollyville Plateau Salamander
Surface-dwelling populations of Jollyville Plateau salamanders have
large, well-developed eyes; wide, yellowish heads; blunt, rounded
snouts; dark greenish-brown bodies; and bright yellowish-orange tails
(Chippindale et al. 2000, pp. 33-34). Some cave forms of Jollyville
Plateau salamanders exhibit cave-associated morphologies, such as eye
reduction, flattening of the head, and dullness or loss of color
(Chippindale et al. 2000, p. 37). Genetic analysis suggests a taxonomic
split
[[Page 50772]]
within this species that appears to correspond to major geologic and
topographic features of the region (Chippindale 2010, p. 2).
Chippindale (2010, pp. 5, 8) concluded that the Jollyville Plateau
salamander exhibits a strong genetic separation between two lineages
within the species: A ``Plateau'' clade that occurs in the Bull Creek,
Walnut Creek, Shoal Creek, Brushy Creek, South Brushy Creek, and
southeastern Lake Travis drainages; and a ``peripheral'' clade that
occurs in the Buttercup Creek and northern Lake Travis drainages
(Chippindale 2010, pp. 5-8). The study also suggests this genetic
separation may actually represent two species (Chippindale 2010, pp. 5,
8). However, a formal, peer-reviewed description of the two possible
species has not been published. We therefore do not recognize a
separation of the Jollyville Plateau salamander into two species
because this split has not been recognized by the scientific community.
The Jollyville Plateau salamander occurs in the Jollyville Plateau
and Brushy Creek areas of the Edwards Plateau in Travis and Williamson
Counties, Texas (Chippindale et al. 2000, pp. 35-36; Bowles et al.
2006, p. 112; Sweet 1982, p. 433). Upon classification as a species,
Jollyville Plateau salamanders were known from Brushy Creek and, within
the Jollyville Plateau, from Bull Creek, Cypress Creek, Long Hollow
Creek, Shoal Creek, and Walnut Creek drainages (Chippindale et al.
2000, p. 36). Since it was described, the Jollyville Plateau salamander
has also been documented within the Lake Creek drainage (O'Donnell et
al. 2006, p. 1). Cave-dwelling Jollyville Plateau salamanders are known
from 1 cave in the Cypress Creek drainage and 12 caves in the Buttercup
Creek cave system in the Brushy Creek drainage (Chippindale et al.
2000, p. 49; Russell 1993, p. 21; Service 1999, p. 6; HNTB 2005, p.
60).
The Jollyville Plateau salamander's spring-fed habitat is typically
characterized by a depth of less than 1 foot (ft) (0.3 meters (m)) of
cool, well oxygenated water (COA 2001, p. 128; Bowles et al. 2006, p.
118) supplied by the underlying Northern Segment of the Edwards Aquifer
(Cole 1995, p. 33). The aquifer that feeds this salamander's habitat is
generally small, shallow, and localized (Chippindale et al. 2000; p.
36, Cole 1995, p. 26). Jollyville Plateau salamanders are typically
found near springs or seep outflows and likely require constant
temperatures (Sweet 1982, pp. 433-434; Bowles et al. 2006, p. 117).
Salamander densities are higher in pools and riffles and in areas with
rubble, cobble, or boulder substrates rather than on solid bedrock (COA
2001, p. 128; Bowles et al. 2006, pp. 114-116). Surface-dwelling
Jollyville Plateau salamanders also occur in subsurface habitat within
the underground aquifer (COA 2001, p. 65; Bowles et al. 2006, p. 118).
For more on habitat, see the ``Proposed Critical Habitat Designation
for the Four Central Texas Salamanders'' of this proposed rule.
Some Jollyville Plateau salamander populations have experienced
decreases in abundance in recent years. City of Austin survey data
indicate that four of the nine sites that were regularly monitored by
City of Austin staff between December 1996 and January 2007 had
statistically significant declines in salamander abundance over 10
years (O'Donnell et al. 2006, p. 4). The average number of salamanders
counted at each of these 4 sites declined from 27 salamanders counted
during surveys from 1996 to 1999 to 4 salamanders counted during
surveys from 2004 to 2007. In 2007, monthly mark-recapture surveys were
conducted in concert with surface counts at three sites in the Bull
Creek watershed (Lanier Spring, Lower Rieblin, and Wheless Spring) over
a 6-to-8-month period to obtain surface population size estimates and
detection probabilities for each site (O'Donnell et al. 2008, p. 11).
Surface population estimates at Lanier Spring varied from 94 to 249,
surface population estimates at the Lower Rieblin site varied from 78
to 126, and surface population estimates at Wheless Spring varied from
187 to 1,024 (O'Donnell et al. 2008, pp. 44-45). These numbers remained
fairly consistent in more recent population estimates for the three
sites (Bendik 2011a, p. 22).
Georgetown Salamander
The Georgetown salamander is characterized by a broad, relatively
short head with three pairs of bright-red gills on each side behind the
jaws, a rounded and short snout, and large eyes with a gold iris. The
upper body is generally grayish with varying patterns of melanophores
(cells containing brown or black pigments called melanin) and
iridophores (cells filled with iridescent pigments called guanine),
while the underside is pale and translucent. The tail tends to be long
with poorly developed dorsal and ventral fins that are golden-yellow at
the base, cream-colored to translucent toward the outer margin, and
mottled with melanophores and iridophores. Unlike the Jollyville
Plateau salamander, the Georgetown salamander has a distinct dark
border along the lateral margins of the tail fin (Chippindale et al.
2000, p. 38). As with the Jollyville Plateau salamander, the Georgetown
salamander has recently discovered cave-adapted forms with reduced eyes
and pale coloration (TPWD 2011a, p. 8).
The Georgetown salamander is known from springs along five
tributaries (South, Middle, and North Forks; Cowan Creek; and Berry
Creek) to the San Gabriel River (Pierce 2011a, p. 2) and from three
caves (aquatic, subterranean locations) in Williamson County, Texas. A
groundwater divide between the South Fork of the San Gabriel River and
Brushy Creek to the south likely creates the division between the
ranges of the Jollyville Plateau and Georgetown salamanders (Williamson
County 2008, p. 3-34). The Service is currently aware of 16 Georgetown
salamander localities. This species has not been observed in recent
years at two locations (San Gabriel Spring and Buford Hollow), despite
several visual survey efforts to find it (Pierce 2011b,c, Southwestern
University, pers. comm.). The current population status is unknown for
four sites due to restricted access (Cedar Breaks, Shadow Canyon, Hogg
Hollow Spring, and Bat Well). Georgetown salamanders continue to be
observed at the remaining 10 sites (Swinbank Spring, Knight Spring,
Twin Springs, Hogg Hollow Spring, Cowan Creek Spring, Cedar Hollow,
Cobbs Cavern Spring, Cobbs Well, Walnut Spring, and Water Tank Cave)
(Pierce 2011c, pers. comm.; Gluesenkamp 2011a, TPWD, pers. comm.).
Recent mark-recapture studies suggest a population size of 100 to 200
adult salamanders at Twin Springs, with a similar population estimate
at Swinbank Spring (Pierce 2011a, p. 18). Population sizes at other
sites are unknown, but visual surface counts result in comparatively
low numbers (Williamson County 2008, pp. 3-35). There are numerous
other springs in Williamson County that may support Georgetown
salamander populations, but private land ownership prevents
investigative surveys (Williamson County 2008, pp. 3-35).
Surface-dwelling Georgetown salamanders inhabit spring runs,
riffles, and pools with gravel and cobble rock substrates (Pierce et
al. 2010, pp. 295-296). This species prefers larger cobble and boulders
to use as cover (Pierce et al. 2010, p. 295). Salamanders are found
within 164 ft (50 m) of a spring opening (Pierce et al. 2011a, p. 4),
but they are most abundant within the first 16.4 ft (5 m) (Pierce et
al. 2010, p. 294). Individuals do not exhibit much movement throughout
the year (Pierce et al. 2010, p. 294). The water chemistry
[[Page 50773]]
of Georgetown salamander habitat is constant year-round in terms of
temperature and dissolved oxygen (Pierce et al. 2010, p. 294, Biagas et
al. in review, p. 8). Little is known about the ecology of Georgetown
salamanders that occupy the cave sites (Cobbs Cavern, Bat Well, and
Water Tank Cave) where this species is known to occur or the quality
and extent of their subterranean habitats. For more on habitat, see the
``Proposed Critical Habitat Designation for the Four Central Texas
Salamanders'' section of this proposed rule.
Salado Salamander
The Salado salamander has reduced eyes compared to other spring-
dwelling Eurycea species in north-central Texas and lacks well-defined
melanophores. It has a relatively long and flat head, and a blunt and
rounded snout. The upper body is generally grayish-brown with a slight
cinnamon tinge and an irregular pattern of tiny, light flecks. The
underside is pale and translucent. The posterior portion of the tail
generally has a well-developed dorsal fin, but the ventral tail fin is
weakly developed (Chippindale et al. 2000, p. 42).
The Salado salamander is known historically from four spring sites
near the village of Salado, Bell County, Texas: Big Boiling Springs
(also known as Main, Salado, or Siren Springs), Lil' Bubbly Spring,
Lazy Days Fish Farm Spring, and Robertson Springs (Chippindale et al.
2000, p. 43; TPWD 2011a, pp. 1-2). These springs bubble up through
faults in the Northern Segment of the Edwards Aquifer and associated
limestone along Salado Creek (Brune 1975, p. 31). The four spring sites
all contribute to Salado Creek. Under Brune's (1975, p. 5) definition,
which identifies springs depending on flow, all sites are considered
small (4.5 to 45 gallons per minute (17 to 170 liters per minute)) to
medium springs (45 to 449 gallons per minute (170 to 1,1700 liters per
minute)). Several other spring sites (Big Bubbly Springs, Critchfield
Springs, and Anderson Springs) are located downstream from Big Boiling
Springs and Robertson Springs. These springs have been surveyed by TPWD
periodically since June 2009, but no salamanders have been found
(Gluesenkamp 2010, pers. comm.). In August 2009, TPWD discovered a
population of salamanders at a new site (Solana Spring 1)
farther upstream on Salado Creek in Bell County, Texas (TPWD 2011a, p.
2). Salado salamanders were recently confirmed at two other spring
sites (Cistern and Hog Hollow Springs) farther upstream on the Salado
Creek in March 2010 (TPWD 2011a, p. 2). In total, the Salado salamander
is known from seven springs. A groundwater divide between Salado Creek
and Berry Creek to the south likely creates a division between the
ranges of the Georgetown and Salado salamander (Williamson County 2008,
p. 3-34).
Of the four salamander species, Salado salamanders are observed the
least and are therefore less understood. Biologists were unable to
observe this species in its type locality (location from which a
specimen was first collected and identified as a species) despite over
20 visits to Big Boiling Springs that occurred between 1991 and 1998
(Chippindale et al. 2000, p. 43). Likewise, TPWD surveyed this site
weekly from June 2009 until May 2010, and found one salamander
(Gluesenkamp 2010, pers. comm.) at a spring outlet locally referred to
as ``Lil' Bubbly'' located just upstream from Big Boiling Springs. One
additional unconfirmed sighting of a Salado salamander in Big Boiling
Springs was reported in 2008, by a citizen of Salado, Texas. In 2009,
TPWD was granted access to Robertson Springs to survey for the Salado
salamander. This species was reconfirmed at this location in February
2010 (Gluesenkamp 2010, pers. comm.). Salado salamander populations
appear to be larger at spring sites upstream of the Village of Salado,
probably due to the higher quality of the habitat (Gluesenkamp 2011c,
pers. comm.). For more on habitat, see the ``Proposed Critical Habitat
Designation for the Four Central Texas Salamanders'' section of this
proposed rule.
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing
regulations at 50 CFR part 424, set forth the procedures for adding
species to the Federal Lists of Endangered and Threatened Wildlife and
Plants. Under section 4(a)(1) of the Act, we may list a species based
on any of the following five factors: (A) The present or threatened
destruction, modification, or curtailment of its habitat or range; (B)
overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) the inadequacy of
existing regulatory mechanisms; and (E) other natural or manmade
factors affecting its continued existence. Listing actions may be
warranted based on any of the above threat factors, singly or in
combination. Each of these factors is discussed below.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
Habitat modification, in the form of degraded water quality and
quantity and disturbance of spring sites, is the primary threat to the
four central Texas salamander species. Water quality degradation in
salamander habitat has been cited as the top concern in several studies
(Chippindale et al. 2000, pp. 36, 40, 43; Bowles et al. 2006, pp. 118-
119; O'Donnell et al. 2006, pp. 45-50), because these salamanders spend
their entire life cycle in water. All of the species have evolved under
natural aquifer conditions both underground and as the water discharges
from natural spring outlets. Deviations from that high water quality
have detrimental effects on salamander ecology, because the aquatic
habitat can be rendered unsuitable for salamanders by changes in water
chemistry, quantity, and flow patterns. Substrate modification is also
a major concern for the salamander species (COA 2001, pp. 101, 126;
Geismar 2005, p. 2; O'Donnell et al. 2006, p. 34). Unobstructed
interstitial space (the space between the rocks) is critical to habitat
of all four salamander species, because it provides cover from
predators and habitat for macroinvertebrate prey items. When the
interstitial spaces become compacted or filled with fine sediment, the
amount of available foraging habitat and protective cover for
salamanders is reduced (Welsh and Ollivier 1998, p. 1,128).
Threats to the habitat of the four central Texas salamanders may
target only the surface habitat, only the subsurface habitat, or both
habitat types. For example, substrate modification degrades the surface
springs and spring-runs but does not impact the subsurface environment,
while water quality degradation impacts both the surface and subsurface
habitats. Because of their ability to retreat to the subsurface
habitat, the four central Texas salamander species may be able to
persist through surface habitat degradation. For example, drought
conditions are common to the region, and these salamanders' ability to
retreat underground may be an evolutionary adaptation to such natural
conditions (Bendik 2011a, pp. 31-32). However, we do not fully
understand the relative importance of the surface and subsurface
habitats to salamander populations. The best available scientific
evidence suggests that surface habitats are important for prey
availability and individual growth. Prey availability for carnivores is
low underground due to the lack of sunlight
[[Page 50774]]
and primary production (Hobbs and Culver 2009, p. 392). In addition,
length measurements taken during a City of Austin mark-recapture study
at Lanier Spring demonstrated that Jollyville Plateau salamanders had
negative growth during a 10-month period of retreating to the
subsurface from 2008 to 2009 (Bendik 2011b, COA, pers. comm.).
Therefore, threats to surface habitat at a given site may not extirpate
any populations of these salamander species, but this type of habitat
degradation may severely limit population growth and increase the
species' overall risk of extinction from other threats.
The majority of the discussion below under Factor A focuses on
evaluating the nature and extent of stressors related to urbanization
within the watershed, the primary source of water quality degradation.
Additionally, other sources of habitat destruction and modification
will be addressed. These include physical habitat modification from
human activities and feral hogs, and environmental events, such as
flooding and drought.
Urbanization Within the Watershed
The ranges of the four salamander species reside within
increasingly urbanized areas of Travis, Williamson, and Bell Counties
that are experiencing rapid human population growth. For example, the
population of the City of Austin grew from 251,808 people in 1970, to
656,562 people in 2000. By 2007, the population had grown to 735,088
people (COA 2007a, p. 1). This represents a 192 percent increase over
the 37-year period. The human population within the City of Georgetown,
Texas, was 28,339 in 2000, and increased to 47,380 by January 2008
(City of Georgetown 2008, pp. 3.3-3.5). The human population is
expected to exceed 225,000 by 2033 (City of Georgetown 2008, p. 3.5),
which would be a 375 percent increase over a 33-year period. Population
projections from the Texas State Data Center (2008, p. 1) estimate that
Travis County will increase in population from 812,280 in 2000, to
1,498,569 in 2040. This would be an 84 percent increase in the human
population size over this 40-year period. The Texas State Data Center
also estimates an increase in human population in Williamson County
from 249,967 in 2000, to 1,742,619 in 2040. This would represent a 597
percent increase over a 40-year timeframe. The human population is not
increasing as rapidly in the range of the Salado salamander, but growth
is occurring. Population projections from the Texas State Data Center
(2009, p. 19) estimate that Bell County will increase in population
from 237,974 in 2000, to 397,741 in 2040, a 67 percent increase over
the 40-year period. By comparison, the national United States'
population is expected to increase from 310,233,000 in 2010, to
405,655,000 in 2040, which is about a 24 percent increase over the 30-
year period (U.S. Census Bureau 2012, p. 1). Growing human populations
increase demand for residential and commercial development, drinking
water supply, wastewater disposal, flood control, and other municipal
goods and services that alter the environment, often degrading
salamander habitat by changing hydrologic regimes, and affecting the
quantity and quality of water resources.
As development increases within the watersheds, more opportunities
exist for the detrimental effects of urbanization to impact salamander
habitat. Urban development upstream of salamander habitat leads to
various stressors on spring systems, including increased flow
velocities, increased sedimentation, increased contamination, changes
in stream morphology and water chemistry, and decreases in groundwater
recharge.
Several researchers have examined the negative impact of
urbanization on stream salamander habitat by making connections between
salamander abundances and levels of development within the watershed.
In 1972, Orser and Shure (p. 1,150) were among the first biologists to
show a decrease in stream salamander density with increasing urban
development. A similar relationship between salamanders and
urbanization was found in North Carolina (Price et al. 2006, pp. 437-
439; Price et al. 2012, p. 198), Maryland, and Virginia (Grant et al.
2009, pp. 1,372-1,375). In central Texas, Bowles et al. (2006, p. 117)
found lower Jollyville Plateau salamander densities in tributaries with
developed watersheds as compared to tributaries with undeveloped
watersheds. Developed tributaries also had higher concentrations of
chloride, magnesium, nitrate-nitrogen, potassium, sodium, and sulfate
(Bowles et al. 2006, p. 117). Several biologists have concluded that
urbanization is one of the largest threats to the future survival of
central Texas salamanders (Bowles et al. 2006, p. 119; Chippindale and
Price 2005, pp. 196-197).
Willson and Dorcas (2003, pp. 768-770) demonstrated that to assess
the impact of urbanization on aquatic salamanders, it is important to
examine development within the entire watershed as opposed to areas
just adjacent to the stream. For example, urban development within the
drainage areas of Austin blind and Jollyville Plateau salamander spring
sites has included residential and commercial structures, golf courses,
and the associated roads and utility pipelines (Cole 1995, p. 28; COA
2001, pp. 10-12).
Because detrimental effects due to urbanization are occurring to
the salamanders' habitats now, and we expect those effects to increase
in the future, we consider urbanization to be a threat to each of the
species. We discuss below how each source of the stressors of
urbanization causes threats to the Austin blind, Jollyville Plateau,
Georgetown, and Salado salamanders' habitats. These sources of impacts
from urbanization include impervious cover and stormwater runoff, land
application contaminants, hazardous material spills, construction
activities, and water quantity reduction.
Impervious Cover and Stormwater Runoff
Impervious cover is any surface material, such as roads, rooftops,
sidewalks, patios, paved surfaces, or compacted soil, that prevents
water from filtering into the soil (Arnold and Gibbons 1996, p. 244).
Once natural vegetation in a watershed is replaced with impervious
cover, rainfall is converted to surface runoff instead of filtering
through the ground (Schueler 1991, p. 114).
As urbanization increases due to human population growth within the
watersheds of salamander habitat, levels of impervious cover will rise.
Various levels of impervious cover within watersheds have been cited as
having detrimental effects to water quality within streams. The
threshold of measurable degradation of stream habitat and loss of
biotic integrity consistently occurs with 6 to 15 percent impervious
cover in contributing watersheds (Bowles et al. 2006, p. 111; Miller et
al. 2007, p. 74). A review of relevant literature by Schueler (1994,
pp. 100-102) indicates that stream degradation occurs at impervious
cover of 10 to 20 percent, a sharp drop in habitat quality is found at
10 to 15 percent impervious cover, and watersheds above 15 percent are
consistently classified as poor, relative to biological condition.
Schueler (1994, p. 102) also concluded that even when water quality
protection practices are widely applied, an impervious cover level of
35 to 60 percent exceeds a threshold beyond which water quality
conditions that existed before development occurred cannot be
maintained.
[[Page 50775]]
Increases in impervious cover resulting from urbanization cause
measurable water quality degradation (Klein 1979, p. 959; Bannerman et
al. 1993, pp. 251-254, 256-258; Center for Watershed Protection 2003,
p. 91). Stressors from impervious cover have demonstrable impacts on
biological communities within streams. Schueler (1994, p. 104) found
that sites receiving runoff from high impervious cover drainage areas
had sensitive aquatic macroinvertebrate species replaced by species
more tolerant of pollution and hydrologic stress (high rate of changes
in discharges over short periods of time). In an analysis of 43 North
Carolina streams, Miller et al. (2007, pp. 78-79) found a strong
negative relationship between impervious cover and the abundance of
larval southern two-lined salamanders (Eurycea cirrigera). Impervious
cover degrades salamander habitat in three ways: (1) Introducing and
concentrating contaminants in stormwater runoff, (2) increasing
sedimentation, and (3) altering the natural flow regime of streams.
Impervious Cover Analysis
To calculate impervious cover within the watersheds occupied by the
four central Texas salamander species, we used the Watershed Boundary
Dataset (USGS 2012, p. 1) to delineate the watersheds where these
species are known to occur along with the 2006 National Land Cover
Dataset (MRLC 2012, p. 1). The Watershed Boundary Dataset is a
nationally consistent watershed dataset developed by the U.S.
Geological Survey (USGS) that is subdivided into 12-digit hydrologic
unit codes, which are the smallest (or finest scale) of the hydrologic
units available. Each of the 12-digit hydrologic unit codes represents
part or all of a surface drainage basin or a combination of drainage
basins, also referred to in the Watershed Boundary Dataset as
``watersheds.'' The 2006 National Land Cover Dataset (the most recent
of the national land cover datasets) was developed by the Multi-
Resolution Land Characteristics Consortium to provide 30-meter spatial
resolution estimates for tree cover and impervious cover percentages
within the contiguous United States.
We identified 15 of the watersheds delineated within the Watershed
Boundary Dataset as being occupied by one of the four central Texas
salamander species. The Jollyville Plateau salamander occurs within six
watersheds (Bull Creek, Cypress Creek, Lake Creek, South Brushy Creek,
Town Lake, and Walnut Creek). The Austin blind salamander occurs within
one watershed (Lake Austin). The Georgetown salamander occurs within
six watersheds (Dry Berry Creek, Lake Georgetown, Lower Berry Creek,
Lower South Fork San Gabriel River, Middle Fork San Gabriel River, and
Smith Branch San Gabriel River). The Salado salamander occurs within
two watersheds (Buttermilk Creek and Mustang Creek).
An impervious cover value (0 to 100 percent) is assigned for each
30-meter pixel within the 2006 National Land Cover Dataset. Using these
values, we calculated the overall average value (percentage) for each
watershed identified. We also identified three categories of impervious
cover for each pixel: (1) 0 percent impervious cover (no impervious
cover was identified within the 30-meter pixel), (2) 1 to 15 percent
impervious cover (between 1 and 15 percent of the 30-meter pixel was
identified as impervious cover), and (3) greater than 15 percent
impervious cover (more than 15 percent of the 30-meter pixel was
identified as impervious cover). For each watershed, we then calculated
the percentage of pixels that fell into each of these three categories.
These percentages are presented in Table 1.
Table 1--Impervious Cover Estimates
----------------------------------------------------------------------------------------------------------------
Categories of impervious Average
Salamander species (total Number of cover (IC) percentage impervious
number of known sites) Watershed salamander ------------------------------- cover (IC)
sites 0% IC 1-15% IC >15% IC percentage
----------------------------------------------------------------------------------------------------------------
Jollyville Plateau salamander Bull Creek....... 64 61 14 25 12.00
(92).
Cypress Creek.... 11 79 9 12 5.72
Lake Creek....... 3 43 17 40 21.35
South Brushy 9 58 17 24 12.52
Creek.
Town Lake........ 4 11 30 59 34.32
Walnut Creek..... 1 34 17 50 28.03
Austin blind salamander (3)... Lake Austin...... 3 54 24 24 11.58
Georgetown salamander (16).... Dry Berry Creek.. 2 92 7 1 0.59
Lake Georgetown.. 6 88 11 2 0.76
Lower Berry Creek 2 73 10 17 3.03
Lower South Fork 1 84 11 6 2.77
San Gabriel
River.
Middle Fork San 4 77 11 12 2.41
Gabriel River.
Smith Branch San 1 61 20 19 9.60
Gabriel River.
Salado salamander (7)......... Buttermilk Creek. 3 95 5 1 0.31
Mustang Creek.... 4 92 7 2 0.91
----------------------------------------------------------------------------------------------------------------
We also identified areas within each watershed that we knew to be
managed as open space. Open space includes lands set aside for either
low-use recreation or wildlife preserves. The protection of open space
helps preserve the quality of water, which is an important component of
salamander surface habitat. Thus, we considered the amount and location
of managed open space, and the potential water quality benefits they
provide to salamander surface habitat during our analysis of threats
caused by impervious cover within each watershed.
The six watersheds within the Jollyville Plateau salamander's range
have overall average impervious cover estimates ranging from
approximately 6 percent (Cypress Creek) to 34 percent (Town Lake). The
majority (64) of the 92 known Jollyville Plateau salamander sites are
located within the Bull Creek watershed, which has an overall average
impervious cover estimate of 12 percent. When average impervious cover
is between 10 and 15 percent within a watershed, sharp declines in
aquatic habitat quality are likely to occur (Schueler 1994, pp. 100-
102).
However, a substantial portion of the land area categorized as open
space and protected as part of the Balcones
[[Page 50776]]
Canyonlands Preserve is located within the Bull Creek watershed. The
Balcones Canyonlands Preserve is managed under the terms and conditions
of a regional habitat conservation plan (HCP) (the Balcones Canyonlands
Conservation Plan HCP) jointly held by the City of Austin and Travis
County as mitigation lands issued under the authority of an Endangered
Species Act section 10(a)(1)(B) permit for the protection of endangered
birds and karst invertebrates. A number of cooperating partners own and
manage lands dedicated to the Balcones Canyonlands Preserve, including
several private landowners, the Lower Colorado River Authority, the
Nature Conservancy of Texas, and the Travis Audubon Society. Although
the permit that created the Balcones Canyonlands Preserve did not
include the Jollyville Plateau salamander, the Balcones Canyonlands
Preserve land management strategies help maintain water quality within
salamander habitats on lands within the preserve. Nonetheless, the City
of Austin has reported significant declines in Jollyville Plateau
salamander abundance at one of their Jollyville Plateau salamander
monitoring sites within Bull Creek (O'Donnell et al. 2006, p. 45), even
though our analysis found that 61 percent of the land within this
watershed has 0 percent impervious cover. The location of this
monitoring site is within a large preserved tract. However, the
headwaters of this drainage are outside the preserve, and the
development in this area increased sedimentation downstream and
impacted salamander habitat in the preserved tract.
The Cypress Creek watershed is the least developed of all of the
watersheds within the Jollyville Plateau salamander's range, and much
of it is extensively covered by lands that are managed as open space.
The vast majority of this open space is part of the Balcones
Canyonlands Preserve. There are 11 spring sites known to be occupied by
the Jollyville Plateau salamander within this watershed. Seven of these
sites are located directly within or downstream from areas dominated by
impervious surfaces. The 2006 National Land Cover Dataset data
indicated that 12 percent of the 30-m pixels in the Cypress Creek
watershed have impervious cover of 15 percent or more and 9 percent of
the 30-m pixels have impervious cover between 1 and 15 percent.
The other watersheds within the Jollyville Plateau salamander's
range have impervious cover levels that may lead to water quality
declines within salamander surface habitat (Schueler 1994, pp. 100-
102). Nine sites known to be occupied by Jollyville Plateau salamanders
are located within the South Brushy Creek watershed, which has an
overall average impervious cover estimate of 13 percent and very little
managed open space. Again, when average impervious cover is between 10
and 15 percent, sharp declines in aquatic habitat quality are likely to
occur (Schueler 1994, pp. 100-102).
The Lake Creek watershed with three known salamander locations and
the Walnut Creek watershed with one known salamander location are
estimated to have 21 percent and 28 percent impervious cover,
respectively. The Lake Creek watershed has two tracts (143 ac (58 ha)
and 95 ac (38 ha)) of managed open space along with two smaller
preserve areas and several municipal parks. Given their small size in
relation to the size of the watershed, it is unknown if these areas
provide any water quality benefits for salamander surface habitat. The
single Jollyville Plateau salamander location within the Walnut Creek
watershed is located on a 53-ac (21-ha) park that is situated directly
adjacent to a residential development. There are two small (14 ac (6
ha) and 67 ac (27 ha)) municipal parks located upstream from this site.
However, the 2006 National Land Cover Dataset data indicated that 50
percent of the 30-m pixels in the Walnut Creek watershed have
impervious cover of 15 percent or more and 17 percent of the 30-m
pixels have impervious cover between 1 and 15 percent. Because this
watershed is extensively covered by impervious surfaces, it is unlikely
that these managed open spaces provide adequate water quality for the
Jollyville Plateau salamander. Salamander counts at the Walnut Creek
location have been low. Although surveys are conducted four times a
year, no salamanders were observed from 2006 to 2009, and only six
individuals were observed in 2010 (Bendik 2011a, p. 13).
The Town Lake watershed is the most developed of all of the
watersheds within the Jollyville Plateau salamander's range. Four
Jollyville Plateau salamander sites are located within the Town Lake
watershed, which has an estimated 30 percent of its 30-m pixels within
the 1 to 15 percent impervious cover category and 59 percent of its 30-
m pixels within the greater than 15 percent impervious cover category.
We could not identify any parcels of land that are managed as open
space within the Town Lake watershed.
The Austin blind salamander occurs within only one of the
watersheds (Lake Austin) delineated within the Watershed Boundary
Dataset. The Lake Austin watershed was estimated to have an overall
average impervious cover estimate of 12 percent. Although each of the
three spring sites where this species is known to occur are located
within a park managed by the City of Austin, the water quality within
the salamander's habitat can be influenced by development throughout
the watershed. The impervious cover within the Lake Austin watershed,
which is an indicator of development intensity within the area, is
within the range that can lead to water quality declines in aquatic
habitats (Schueler 1994, pp. 100-102). Some Balcones Canyonlands
Preserve lands are located within the Lake Austin watershed, which
likely contribute some water quality benefits to surface flow. However,
the Austin blind salamander is, in large part, a subterranean species.
Therefore, water quality within this species' habitat can be influenced
by land use throughout the recharge zone of the Barton Springs Segment
of the Edwards Aquifer.
The Lower Colorado River Authority (LCRA 2002, pp. 3-54--3-55)
conducted a water supply study of the recharge and contributing zone
areas within the Barton Springs Segment of the Edwards Aquifer that
examined the amount of impervious cover within the local area. The
eight watersheds within the area had a range of impervious cover from 3
percent to 29 percent in 2000. The projected impervious cover limits
for the same eight watersheds in 2025 ranged from 5 percent to 32
percent (LCRA 2002, pp. 4-12--4-13). The two watersheds, Williamson
Creek and Sunset Valley Creek (a tributary to Williamson Creek), with
the highest percentage of impervious cover (16 and 29 percent,
respectively) are also the second and third closest to Barton Springs
(LCRA 2002, pp. 4-12--4-13).
The six watersheds within the Georgetown salamander's range have
overall average impervious cover estimates ranging from 0.59 percent
(Dry Berry Creek) to about 10 percent (Smith Branch San Gabriel River).
The overall average impervious cover estimates for each of the six
watersheds are below the levels that have been shown to lead to sharp
water quality declines in aquatic habitats (Schueler 1994, pp. 100-
102). Two (Cobbs Spring and Cobbs Spring Well) of the 16 sites known to
be occupied by the Georgetown salamander occur in the headwaters of the
Dry Berry Creek watershed, which has an overall average impervious
cover estimate of 0.59 percent.
Six spring sites known to be occupied by Georgetown salamander are
located within the Lake Georgetown watershed.
[[Page 50777]]
This watershed also has one of the least overall average impervious
cover estimates (0.76 percent) of the six watersheds within the
Georgetown salamander's range. These six sites, along with three of the
four spring sites known to be occupied by the Georgetown salamander in
the Middle Fork San Gabriel River watershed (with an overall average
impervious cover estimate of about 2 percent) and the only known
Georgetown salamander site within the Lower South Fork San Gabriel
River watershed (with an overall average impervious cover estimate of
about 3 percent), are located upstream from the urbanized areas
associated with the City of Georgetown. Therefore, these sites are
likely not as affected by water quality degradation currently as those
spring sites occupied by the Georgetown salamander within the highly
urbanized areas of the City of Georgetown.
We identified two tracts of land managed specifically as open space
within the Georgetown salamander's range. Williamson County manages a
64-ac (26-ha) conservation easement at Cobbs Cavern and owns the 145-ac
(59-ha) Twin Springs Preserve. The Twin Springs preserve contains one
Georgetown salamander site. While the Cobbs Cavern conservation
easement does not include the Cobbs Spring or Cobbs well site, it does
contain land in the watershed for these sites. Despite the protection
of these two tracts, water quality at these sites can be influenced by
activities occurring throughout the recharge zone. Without more managed
open space within this species' range, it is unlikely that water
quality within the Georgetown salamander's surface habitat will be
protected as development continues in these watersheds into the future.
Four of the 16 sites known to be occupied by the Georgetown
salamander are located in areas identified as having impervious cover
estimates (either in the 1 to 15 percent impervious cover category or
the greater than 15 percent impervious cover category) within the range
that can lead to water quality declines (10 to 15 percent) or poor
water quality relative to biological condition (greater than 15
percent) in aquatic habitats (Schueler 1994, pp. 100-102). These
include one site in the Middle Fork San Gabriel River watershed, the
only occupied site within the Smith Branch San Gabriel River watershed
(with an overall average impervious cover estimate of about 10
percent), and the two occupied sites within the Lower Berry Creek
watershed (with an overall average impervious cover estimate of about 3
percent). Although the overall average impervious cover estimate within
Lower Berry Creek watershed is below the level that has been shown to
lead to water quality declines in aquatic habitats (Schueler 1994, pp.
100-102), 17 percent of the watershed has greater than 15 percent
impervious cover. These two Georgetown salamander sites are located in
the most developed area of this watershed. As such, these sites are
vulnerable to water quality degradation caused by pollutants associated
with highly urbanized areas.
The Salado salamander occurs within two of the watersheds
delineated within the Watershed Boundary Dataset. Buttermilk Creek and
Mustang Creek watersheds have overall average impervious cover
estimates of 0.31 percent and 0.91 percent, respectively. Although
these impervious cover levels are well below that which are likely to
lead to water quality declines in aquatic habitats (Schueler 1994, pp.
100-102), three of the seven springs sites known to be occupied by the
Salado salamander are directly within urbanized habitats in the Mustang
Creek watershed (within the Village of Salado), and therefore, may be
more susceptible to spills of hazardous materials and pollutants from
roads that are close to locations where salamanders are known to occur.
Four spring sites known to be occupied by Salado salamanders are
upstream from the urbanized areas associated with the Village of
Salado. Three of these spring sites are located within the Buttermilk
Creek watershed on an approximately 8,126-ac (3,288-ha) ranch that is
privately owned and almost entirely undeveloped. Another spring site
known to be occupied by the Salado salamander within the Mustang Creek
watershed is located on another privately owned and almost entirely
undeveloped ranch that is approximately 827 ac (335 ha) in size. Both
ranches are located upstream of the impervious cover areas associated
with the Village of Salado and entirely within the recharge zone of the
Northern Segment of the Edwards Aquifer. Although impervious cover is
not currently a threat to these upstream sites, a significant portion
of the recharge zone extends to areas off of these properties and
spring water quality can be impacted by activities occurring some
distance away.
We could not identify any large tracts of lands managed
specifically as open space within the Salado salamander's range,
particularly upstream of sites where this species is known to occur. In
addition, there are no agreements in place to preserve or manage the
above-mentioned properties for the benefit of the Salado salamander or
its surface habitat. Without these, it is unlikely that water quality
within the Salado salamander's surface habitat will be protected if
development occurs in these watersheds in the future.
Although the data for this level of the impervious cover analysis
were derived using the finest scale hydrologic units readily available
in the Watershed Boundary Dataset, they offer no reference to the
location of salamander-occupied spring sites in relation to the
location of impervious cover within the watersheds. Therefore,
impervious cover occurring within each watershed may not necessarily be
an indicator of how much impervious cover is impacting water quality
within known salamander sites because this analysis does not take into
account whether the salamander sites are found upstream or downstream
of impervious surfaces associated with developed areas. Moreover,
because the most recent impervious cover estimates available within the
National Land Cover Dataset were provided from 2006 data, more
impervious cover could be present within the watersheds than are
indicated in our analysis. By mapping the spring sites where
salamanders are known to occur over the 2006 National Land Cover
Dataset impervious cover data layer, we can generally discuss which
sites may currently be affected by water quality degradation due to
their location within the three impervious cover categories mentioned
above and identified in Table 1.
To provide a general indication of how much impervious cover may be
influencing surface water quality at individual salamander sites, we
used 2010 aerial photos to visually estimate the amount of impervious
cover upstream of each site known to be occupied by the Jollyville
Plateau, Georgetown, or Salado salamander. By visually examining the
aerial photos from 2010, we classified the areas within each tributary
watershed upstream from each known salamander site into one of four
categories (that represent approximations of impervious cover levels).
We defined these categories as follows: (1) None (a tributary watershed
with no visible impervious cover), (2) low (a tributary watershed with
what appeared to be less than 10 percent impervious cover), (3)
moderate (a tributary watershed with what appeared to be impervious
cover between 10 and 30 percent), and (4) high (a tributary watershed
with what appeared to be greater than 30 percent impervious cover). A
summary of the number of salamander sites for each of these three
species found to be within
[[Page 50778]]
the impervious cover categories is provided below (Table 2).
Table 2--Impervious Cover Estimates Upstream of Known Salamander Locations
----------------------------------------------------------------------------------------------------------------
Number of Number of sites with impervious cover levels
Salamander species salamander ---------------------------------------------------------------
sites None Low Moderate High
----------------------------------------------------------------------------------------------------------------
Jollyville Plateau salamander... 92 17 6 21 48
Georgetown salamander........... 16 4 9 2 1
Salado Salamander............... 7 2 4 0 1
----------------------------------------------------------------------------------------------------------------
The Austin blind salamander was not considered in the analysis of
impervious cover upstream of its known sites, as it primarily occurs
below the surface and is more likely to be impacted by water quality
changes due to impervious cover throughout the Edward Aquifer's
recharge zone. Using the 2006 National Land Cover Database, we
determined that the recharge zone of the Barton Springs Segment of the
Edwards Aquifer had an overall average impervious cover level of 5.87
percent. However, at least 12 percent of the recharge zone has greater
than 15 percent impervious cover.
Contaminants in Stormwater Runoff
Urban environments are host to a variety of human activities that
generate many types of point source (``end of pipe'') and non-point
source (coming from many diffuse sources) contaminants. These sources
of contaminants, when combined, often degrade nearby waterways and
aquatic resources within the watershed. Urban contaminants commonly
detected in stormwater include elevated levels of suspended solids,
nutrients, trace metals, pesticides, and coliform bacteria. Similarly,
various industrial and municipal activities result in the discharge of
treated wastewater or unintentional release of industrial contaminants
as point source pollution.
Stormwater runoff carries these contaminants into stream systems
(Bannerman et al. 1993, pp. 251-254, 256-258; Schueler 1994, p. 102;
Barrett and Charbeneau 1996, p. 87; Center for Watershed Protection
2003, p. 91). Amphibians, especially their eggs and larvae (which are
usually restricted to a small area within an aquatic environment), are
sensitive to many different aquatic pollutants (Harfenist et al. 1989,
pp. 4-57). Contaminants found in aquatic environments, even at
sublethal concentrations, may interfere with a salamander's ability to
develop, grow, or reproduce (Burton and Ingersoll 1994, pp. 120, 125).
Central Texas spring salamanders are particularly vulnerable to
contaminants, because they have evolved under very stable environmental
conditions, remain aquatic throughout their entire life cycle, have
highly permeable skin, have severely restricted ranges, and cannot
escape contaminants in their environment (Turner and O'Donnell 2004, p.
5). In addition, macroinvertebrates, such as small freshwater
crustaceans, that aquatic salamanders feed on are especially sensitive
to water pollution (Phipps et al. 1995, p. 282; Miller et al. 2007, p.
74). Studies in the Bull Creek watershed in Austin, Texas, found a loss
of some sensitive macroinvertebrate species, potentially due to
contaminants of nutrient enrichment and sediment accumulation (COA
2001, p. 15; COA 2010a, p. 16).
Both nationally and locally, consistent relationships between
impervious cover and water quality degradation through contaminant
loading have been documented. In a study of contaminant loads from
various land use areas in Austin, stormwater runoff loads were found to
increase with increasing impervious cover (COA 1990, pp. 12-14). This
study also found that contaminant loading rates of the more urbanized
watersheds were higher than those of the small suburban watersheds.
Soeur et al. (1995, p. 565) determined that stormwater contaminant
loading positively correlated with development intensity in Austin. In
a study of 38 small watersheds in the Austin area, 7 different
contaminants were found to be positively correlated with impervious
cover (COA 2006, p. 35). Using stream data from 1958 to 2007 at 24
Austin-area sites, Glick et al. (2009, p. 9) found that the City of
Austin's water quality index had a strong negative correlation with
impervious cover.
Polycyclic aromatic hydrocarbons (PAHs) are a common form of
aquatic contaminants in urbanized areas that could potentially affect
salamanders, their habitat, or their prey. This form of pollution can
originate from petroleum products, such as oil or grease, or from
atmospheric deposition as a byproduct of combustion (for example,
vehicular combustion). These pollutants accumulate over time on
impervious cover, contaminating water supplies through urban and
highway runoff (Van Metre et al. 2000, p. 4,067; Albers 2003, pp. 345-
346). The main source of PAH loading in Austin-area streams is parking
lots with coal tar emulsion sealant, even though this type of lot only
covers 1 to 2 percent of the watersheds (Mahler et al. 2005, p. 5565).
A recent analysis of the rate of wear on coal tar lots revealed that
the sealcoat wears off relatively quickly and contributes more to PAH
loading than previously thought (Scoggins et al. 2009, p. 4914).
Petroleum and petroleum byproducts can adversely affect living
organisms by causing direct toxic action, altering water chemistry,
reducing light, and decreasing food availability (Albers 2003, p. 349).
Exposure to PAHs at levels found within the Jollyville Plateau
salamander's range can cause impaired reproduction, reduced growth and
development, and tumors or cancer in species of amphibians, reptiles,
and other organisms (Albers 2003, p. 354). Coal tar pavement sealant
slowed hatching, growth, and development of a frog (Xenopus laevis) in
a laboratory setting (Bryer et al. 2006, pp. 244-245). High
concentrations of PAHs from coal tar sealant negatively affected the
righting ability (amount of time needed to flip over after being placed
on back) of adult eastern newts (Notophthalmus viridescens) and may
have also damaged the newt's liver (Sparling et al. 2009, pp. 18-20).
For juvenile spotted salamanders (Ambystoma maculatum), PAHs reduced
growth in the lab (Sparling et al. 2009, p. 28). In a lab study using
the same coal tar sealant once used by the City of Austin, Bommarito et
al. (2010, pp. 1151-1152) found that spotted salamanders displayed
slower growth rates and diminished swimming ability when exposed to
PAHs. PAHs are also known to cause death, reduced survival, altered
physiological function, inhibited reproduction, and changes in
[[Page 50779]]
community composition of freshwater invertebrates (Albers 2003, p.
352).
Limited sampling by the City of Austin has detected PAHs at
concentrations of concern at multiple sites within the range of the
Jollyville Plateau salamander. Most notable were the elevated levels of
nine different PAH compounds at the Spicewood Springs site in the Shoal
Creek drainage area (O'Donnell et al. 2005, pp. 16-17). This is also
one of the sites where salamanders have shown a significant decline in
abundance during the City of Austin's long-term monitoring studies
(O'Donnell et al. 2006, p. 47). Another study found several PAH
compounds in seven Austin-area streams, including Barton, Bull, and
Walnut Creeks, downstream of coal tar sealant parking lots (Scoggins et
al. 2007, p. 697). Sites with high concentrations of PAHs (located in
Barton and Walnut Creeks) had fewer macroinvertebrate species and lower
macroinvertebrate density (Scoggins et al. 2007, p. 700). This form of
contamination has also been detected at Barton Springs, which is the
Austin blind salamander's habitat (COA 1997, p. 10). Because PAHs can
adversely affect salamanders, PAHs have been found in the range of the
species, and we expect an increase of this contaminant in the future in
conjunction with the increase of urbanization, we consider
contamination from PAHs to be a threat to the continued existence of
all four central Texas salamanders now and in the future.
Conductivity is a measure of the ability of water to carry an
electrical current and can be used to approximate the concentration of
dissolved inorganic solids in water that can alter the internal water
balance in aquatic organisms, affecting the four central Texas
salamanders' survival. As ion concentrations such as chlorides, sodium,
sulfates, and nitrates rise, conductivity will increase. These
compounds are the chemical products, or byproducts, of many common
pollutants that originate from urban environments (Menzer and Nelson
1980, p. 633), which are often transported to streams via stormwater
runoff from impervious cover. Measurements by the City of Austin
between 1997 and 2006 found that conductivity averaged between 550 and
650 microsiemens per centimeter ([mu]S cm-1) at rural
springs with low or no development and averaged between 900 and 1000
[mu]S cm-1 at monitoring sites in watersheds with urban
development (O'Donnell et al. 2006, p. 37). The City of Austin also
found increasing ions with increasing impervious cover at four
Jollyville Plateau salamander sites (Herrington et al. 2007, p. 13).
These results indicate that developed watersheds contribute to higher
levels of water contaminants in salamander habitats.
High conductivity has been associated with declining salamander
abundance. For example, three of the four sites with statistically
significant declining Jollyville Plateau salamander abundance from 1997
to 2006 are cited as having high conductivity readings (O'Donnell et
al. 2006, p. 37). Similar correlations were shown in studies comparing
developed and undeveloped sites from 1996 to 1998 (Bowles et al. 2006,
pp. 117-118). This analysis found significantly lower numbers of
salamanders and significantly higher measures of specific conductance
at developed sites as compared to undeveloped sites (Bowles et al.
2006, pp. 117-118). Tributary 5 of Bull Creek has had an increase in
conductivity, chloride, and sodium and a decrease in invertebrate
diversity from 1996 to 2008 (COA 2010a, p. 16). Only one Jollyville
Plateau salamander has been observed here from 2009 to 2010 in
quarterly surveys (Bendik 2011a, p. 16). Poor water quality, as
measured by high specific conductance and elevated levels of ion
concentrations, is cited as one of the likely factors leading to
statistically significant declines in salamander abundance at the City
of Austin's long-term monitoring sites (O'Donnell et al. 2006, p. 46).
In an analysis performed by the City of Austin (Turner 2005a, p.
6), significant changes over time were reported for several chemical
constituents and physical parameters in Barton Springs Pool, which
could be attributed to impacts from watershed urbanization.
Conductivity, turbidity, sulfates, and total organic carbon have
increased while the concentration of dissolved oxygen has decreased
(Turner 2005a, pp. 8-17). The significance and presence of trends in
other pollutants were variable depending on flow conditions (baseflow
vs. stormflow, recharge vs. non-recharge) (Turner 2005a, p. 20). A
similar analysis by Herrington and Hiers (2010, p. 2) examined water
quality at Barton Springs Pool and other Barton Springs outlets where
Austin blind salamanders are found (Sunken Gardens and Eliza Springs)
over a general period of the mid-1990s to the summer of 2009.
Herrington and Hiers (2010, pp. 41-42) found that dissolved oxygen
decreased over time in the Barton Springs Pool, while conductivity and
nitrogen increased. However, this decline in water quality was not seen
in Sunken Gardens Spring or Elisa Spring (Herrington 2010, p. 42). A
separate analysis found that ions such as chloride and sulfate
increased in Barton Creek despite the enactment of city-wide water
quality control ordinances (Turner 2007, p. 7). Overall, these studies
indicate a long-term trend of water quality degradation at Barton
Springs over a 34-year period (1975 to 2009).
In summary, there are many different types of contaminants found in
stormwater runoff that can have detrimental effects on the four central
Texas salamanders. Impervious cover increases the transport of
contaminants common in urban environments, and we expect this
detrimental effect to increase in the future with increased
urbanization. Therefore, the current existence and future increase of
contaminants in stormwater runoff is a significant threat to all four
central Texas salamanders' surface and subsurface habitats throughout
their ranges. However, due to the relatively low levels of impervious
cover in its range, the Salado salamander is currently, and anticipated
to be, less affected.
Sedimentation from Stormwater Runoff
Elevated mobilization of sediment (mixture of silt, sand, clay, and
organic debris) occurs as a result of increased velocity of water
running off impervious surfaces (Schram 1995, p. 88; Arnold and Gibbons
1996, pp. 244-245). Increased rates of stormwater runoff cause
increased erosion through scouring in headwater areas and sediment
deposition in downstream channels (Booth 1991, pp. 93, 102-105; Schram
1995, p. 88). Waterways are adversely affected in urban areas, where
impervious cover rates are high, by sediment loads that are washed into
streams or aquifers during storm events. Sediments are either deposited
into layers or become suspended in the water column (Ford and Williams
1989, p. 537; Mahler and Lynch 1999, p. 177). Sediment derived from
soil erosion has been cited as the greatest single source of pollution
of surface waters by volume (Menzer and Nelson 1980, p. 632).
Excessive sediment from stormwater runoff is a threat to
salamanders because it can cover habitat, cover substrates, and lead to
declines in vegetative abundance and diversity (Geismar 2005, p. 2).
Sediments suspended in water can clog gill structures, which impairs
breathing of aquatic organisms, and can reduce their ability to avoid
predators or locate food sources due to decreased visibility (Schueler
1987, p. 1.5). Excessive deposition of sediment in streams can
physically reduce the
[[Page 50780]]
amount of available habitat and protective cover for aquatic organisms,
by filling the interstitial spaces of gravel and rocks. As an example,
a California study found that densities of two salamander species were
significantly lower in streams that experienced a large infusion of
sediment from road construction after a storm event (Welsh and Ollivier
1998, pp. 1,118-1,132). The vulnerability of the salamander species in
this California study was attributed to their reliance on interstitial
spaces in the streambed habitats (Welsh and Ollivier 1998, p. 1,128).
We consider increased sedimentation from impervious cover to be a
threat to all four central Texas salamanders, because it fills
interstitial spaces, eliminates resting places, and reduces habitat of
its prey base (small aquatic invertebrates) (O'Donnell et al. 2006, p.
34).
Also, sediments eroded from contaminated soil surfaces can
concentrate and transport contaminants (Mahler and Lynch 1999, p. 165).
The four central Texas salamander species and their prey species are
directly exposed to sediment-borne contaminants present within the
aquifer and discharging through the spring outlets. For example, in
addition to sediment, trace metals such as arsenic, cadmium, copper,
lead, nickel, and zinc were found in Barton Springs in the early 1990s
(COA 1997, pp. 229, 231-232). Contaminants may cause adverse effects to
the salamander and its prey species including reduced growth and
weight, abnormal behavior, morphological and developmental aberrations,
and decreased reproductive activity (Albers 2003, p. 354).
Excess sedimentation may have contributed to declines in Jollyville
Plateau salamander populations in the past. Monitoring by the City of
Austin found that, as sediment deposition increased at several sites,
salamander abundances significantly decreased (COA 2001, pp. 101, 126).
Additionally, the City of Austin found that sediment deposition rates
have increased significantly along one of the long-term monitoring
sites (Bull Creek Tributary 5) as a result of construction activities
upstream (O'Donnell et al. 2006, p. 34). This site has had significant
declines in salamander abundance, based on 10 years of monitoring, and
the City of Austin attributes this decline to the increases in
sedimentation (O'Donnell et al. 2006, pp. 34-35). The location of this
monitoring site is within a large preserved tract. However, the
headwaters of this drainage are outside the preserve and the
development in this area increased sedimentation downstream and
impacted salamander habitat in the preserved tract.
Direct evidence of the effects of sedimentation on the Austin
blind, Georgetown, and Salado salamanders is lacking, primarily due to
limited studies on those species. However, analogies can be drawn from
data on similar species, such as the Jollyville Plateau and Barton
Springs salamanders. Barton Spring salamander population numbers are
adversely affected by high turbidity and sedimentation (COA 1997, p.
13). Sediments discharge through Barton Springs, even during baseflow
conditions (not related to a storm event) (Geismar 2005, p. 12). Storms
can increase sedimentation rates substantially (Geismar 2005, p. 12).
Areas in the immediate vicinity of the spring outflows lack sediment,
but the remaining bedrock is sometimes covered with a layer of sediment
several inches thick (Geismar 2005, p. 5). Sedimentation is a direct
threat for the Austin blind salamander because its habitat in Barton
Springs would fill with sediment if it were not for regular maintenance
and removal (Geismar 2005, p. 12). Further development in the Barton
Creek watershed will most likely be associated with diminished water
clarity and a reduction in biodiversity of flora (COA 1997, p. 7).
Likewise, development within the watersheds of Georgetown and Salado
salamander sites will increase sedimentation and degrade water quality
in salamander habitat. Therefore, because salamander population numbers
are adversely affected by sedimentation covering habitat, filling in
substrates, and transporting contaminants in both surface and
subsurface habitats, we consider sedimentation and its resulting
effects to be an ongoing, significant threat to all four central Texas
salamanders' surface and subsurface habitats now and in the future.
However, we consider the Salado salamander to salamander to be less
affected by this threat than the other three species, due to the
relatively low levels of impervious cover in its range.
Changes in Flow Regime Due to Impervious Cover
Impervious cover in a stream's watershed causes streamflow to shift
from predominately baseflow, which is derived from natural filtration
processes and discharges from local groundwater supplies, to
predominately stormwater runoff. With increasing stormwater runoff, the
amount of baseflow available to sustain water supplies during drought
cycles is diminished and the frequency and severity of flooding
increases. The increased quantity and velocity of runoff increases
erosion and streambank destabilization, which in turn leads to
increased sediment loadings, channel widening, and detrimental changes
in the morphology and aquatic ecology of the affected stream system
(Hammer 1972, pp. 1535-1536, 1540; Booth 1990, pp. 407-409, 412-414;
Booth and Reinelt 1993, pp. 548-550; Schueler 1994, pp. 106-108;
Pizzuto et al. 2000, p. 82; Center for Watershed Protection 2003, pp.
41-48).
The changes in flow regime due to impervious cover can have a
direct impact on salamander populations. For example, Barrett et al.
(2010, pp. 2002-2003) recently observed that the density of aquatic
southern two-lined salamanders declined more drastically in streams
with urbanized watersheds compared to streams with forested or pastured
watersheds. A statistical analysis indicated that this decline in urban
streams was due to an increase in flooding frequency from stormwater
runoff. Barrett et al. (2010, p. 2003) also used artificial stream
experiments to demonstrate that salamanders were flushed downstream at
significantly lower velocities when the substrate was sand-based, as
compared to gravel, pebble, or cobble-based. Sand-based substrates are
common to urban streams due to high sedimentation rates (see
``Sedimentation from Stormwater Runoff'' section, above). The combined
effects of increased sand-based substrates due to high sedimentation
rates, and increased flow velocities from impervious cover, result in
effectively removing salamanders from their habitat.
Extreme flood events have occurred in all four salamander species'
surface habitats (Pierce 2011a, p. 10; TPWD 2011a, p. 6; Turner 2009,
p. 11; O'Donnell et al. 2005, p. 15). It is reasonable to assume that
impervious cover due to urbanization in the salamanders' watershed will
continue to cause streamflow to shift from predominately baseflow to
predominately stormwater runoff. For example, an examination of 24
stream sites in the Austin area revealed that increasing impervious
cover in the watersheds resulted in decreased base flow, increased
high-flow events of shorter duration, and more rapid rises and falls of
the stream flow (Glick et al. 2009, p. 9). In addition, increases in
impervious cover within the Walnut Creek watershed (Jollyville Plateau
salamander habitat) have probably caused a shift to more rapid rises
and falls of the stream flow (Herrington 2010, p. 11). Because of the
detrimental effects previously discussed in association with increased
stormwater
[[Page 50781]]
runoff, and because the amount of baseflow available to sustain water
supplies during drought cycles is diminished, we consider changes in
flow regime due to impervious cover to be an ongoing threat to all four
central Texas salamanders' surface habitats now and in the future.
Because it only affects surface habitat, this threat is of moderate
significance to the Austin blind, Jollyville Plateau, and Georgetown
salamanders. We consider this threat to be of low significance for the
Salado salamander due to the relatively low levels of impervious cover
in its range.
Conclusion of Impervious Cover and Stormwater Runoff
In summary, impervious cover contributes to the degradation of
surface and subsurface salamander habitat by transporting contaminants
and sediments to the Edwards Aquifer. Impervious cover within the
watersheds of the salamanders also leads to changes in streamflow
regime that degrades surface salamander habitat. The Austin blind,
Jollyville Plateau, and Georgetown salamanders all have levels of
impervious cover in their ranges that may be causing declines in water
quality. Impervious cover levels are relatively low in the range of the
Salado salamander. However, growing human populations and the
associated increase in urbanization indicate that impervious cover
levels will continue to rise within the ranges of all four central
Texas salamanders. Therefore, we consider impervious cover and
stormwater runoff to be sources of stressors, such as contamination,
sedimentation, and changes in streamwater's flow regime, that
contribute to the overall risk of extinction for all four salamander
species.
Land Application Contaminants
Excessive land application contaminants, such as nutrient and
pesticide input to watershed drainages, are other forms of pollution
that occur in highly urbanized areas. In comparison to nonkarstic
aquifer systems, the Edwards Aquifer is more vulnerable to the effects
of contamination due to: (1) A large number of conduits that offer no
filtering capacity, (2) high groundwater flow velocities, and (3) the
relatively short amount of time that water is inside the aquifer system
(Ford and Williams 1989, pp. 518-519).
Even at low concentrations, land application contaminants, such as
nutrients and pesticides, can disrupt aquatic life. Some of these
chemicals may accumulate in the fatty tissue of aquatic organisms and
impair their ability to reproduce, escape predation, maintain metabolic
processes, and survive (Ross 2011, p. 6). In addition,
macroinvertebrates, such as small freshwater crustaceans on which these
four central Texas salamander species feed are especially sensitive to
water pollution (Phipps et al. 1995, p. 282; Miller et al. 2007, p.
74).
Nutrients
Nutrient input (such as phosphorus and nitrogen) to watershed
drainages, which often results in abnormally high organic growth in
aquatic ecosystems, can originate from multiple sources, such as human
and animal wastes, industrial pollutants, and fertilizers (from lawns,
golf courses, or croplands) (Garner and Mahler 2007, p. 29). As the
human population grows and subsequent urbanization occurs within the
ranges of these four central Texas salamander species, they likely
become more susceptible to the effects of excessive nutrients within
their habitats. To illustrate, an estimated 102,262 domestic dogs and
cats (pet waste is a potential source of excessive nutrients) were
known to occur within the Barton Springs Segment of the Edwards Aquifer
in 2010 (Herrington et al. 2010, p. 15). Their distributions were
correlated with human population density (Herrington et al. 2010, p.
15).
Various residential properties and golf courses are known to use
pesticides, herbicides, and fertilizers to maintain turfgrass within
watersheds where Jollyville Plateau salamander populations are known to
occur (COA 2003, pp. 1-7). Analysis of water quality constituents
conducted by the City of Austin (1997, pp. 8-9) showed significant
differences in nitrate, ammonia, total dissolved solids, total
suspended solids, and turbidity concentrations between watersheds
dominanted by golf courses, residential land, and rural land. Golf
course tributaries were found to have higher concentrations of these
constituents than residential tributaries, and both golf course and
residential tributaries had substantially higher concentrations for
these five constituents than rural tributaries (COA 1997, pp. 8-9).
Residential irrigation of wastewater effluent has led to excessive
nutrient input into the recharge zone of the Barton Springs Segment of
the Edwards Aquifer (Ross 2011, pp. 11-18). Wastewater effluent permits
do not require treatment to remove metals, pharmaceutical chemicals, or
the wide range of chemicals found in body care products, soaps,
detergents, pesticides, or other cleaning products (Ross 2011, p. 6).
These chemicals remaining in treated wastewater effluent can enter
streams and the aquifer and alter water quality within salamander
habitat.
Excessive nutrient input into aquatic systems can increase plant
growth, which pulls more oxygen out of the water when the dead plant
matter decomposes, resulting in less oxygen being available in the
water for salamanders to breathe (Schueler 1987, pp. 1.5-1.6; Ross
2011, p. 7). A reduction in dissolved oxygen concentrations could not
only affect respiration in salamander species, but also lead to
decreased metabolic functioning and growth in juveniles (Woods et al.
2010, p. 544), or death (Ross 2011, p. 6). Excessive plant material can
also reduce stream velocities and increase sediment deposition (Ross
2011, p. 7). When the interstitial spaces become compacted or filled
with fine sediment, the amount of available foraging habitat and
protective cover is reduced (Welsh and Ollivier 1998, p. 1,128).
Studies in the Bull Creek watershed found a loss of some sensitive
macroinvertebrate species, potentially due to nutrient enrichment and
sediment accumulation (COA 2001b, p. 15).
Poor water quality, particularly elevated nitrates, may also be a
cause of morphological deformities in individual Jollyville Plateau
salamanders. The City of Austin has documented very high levels of
nitrates (averaging over 6 milligrams per liter (mg L\-1\) with some
samples exceeding 10 mg L\-1\) and high conductivity at two monitoring
sites in the Stillhouse Hollow drainage area (O'Donnell et al. 2006,
pp. 26, 37). For comparison, nitrate levels in undeveloped Edwards
Aquifer springs (watersheds without high levels of urbanization) are
typically close to 1 mg L\-1\ (O'Donnell et al. 2006, p. 26). The
source of the nitrates in Stillhouse Hollow is thought to be lawn
fertilizers (Turner 2005b, p. 11). Salamanders observed at the
Stillhouse Hollow monitoring sites have shown high incidences of
deformities, such as curved spines, missing eyes, missing limbs or
digits, and eye injuries (O'Donnell et al. 2006, p. 26). These
deformities often result in the salamander's inability to feed,
reproduce, or survive. The Stillhouse Hollow location was also cited as
having the highest observation of dead salamanders (COA 2001, p. 88).
Although no statistical correlations were found between the number of
deformities and nitrate concentrations (O'Donnell et al. 2006, p. 26),
environmental toxins are the suspected cause of salamander deformities
[[Page 50782]]
(O'Donnell et al. 2006, p. 25). Nitrate toxicity studies have indicated
that salamanders and other amphibians are sensitive to these pollutants
(Marco et al. 1999, p. 2,837). Increased nitrate levels have been known
to affect amphibians by altering feeding activity and causing
disequilibrium and physical abnormalities (Marco et al. 1999, p.
2,837).
In summary, as the human population grows and subsequent
urbanization occurs within the ranges of these four central Texas
salamander species, they likely will become more susceptible to the
effects of excessive nutrients within their surface and subsurface
habitats. Because of the detrimental effects associated with increased
nutrient input, we consider nutrients to be an ongoing threat to all
four central Texas salamanders' continued existence throughout their
ranges.
Pesticides
Pesticides are also associated with urban areas. Sources of
pesticides include lawns, road rights-of-way, and managed turf areas,
such as golf courses, parks, and ball fields. Pesticide application is
also common in residential, recreational, and agricultural areas.
Pesticides have the potential to leach into groundwater through the
soil or be washed into streams by stormwater runoff.
Some of the most widely used pesticides in the United States are
atrazine, carbaryl, diazinon, and simazine (Mahler and Van Metre 2000,
p. 1). These four pesticides were documented within the Austin blind
salamander's habitat (Barton Springs Pool and Eliza Springs) in water
samples taken at Barton Springs during and after a 2-day storm event
(Mahler and Van Metre 2000, pp. 1, 6, 8). They were found at levels
below criteria set in the aquatic life protection section of the Texas
Surface Water Quality Standards (Mahler and Van Metre 2000, p. 4). In
addition, elevated concentrations of organochlorine pesticides were
found in Barton Springs sediments (Ingersoll et al. 2001, p. 7). A
later water quality study at Barton Springs from 2003 to 2005 detected
atrazine, simazine, prometon, and deethylatrazine in low concentrations
(Mahler et al. 2006, p. 63). During storm events, additional
contaminants were detected, including pharmaceutical compounds such as
caffeine, acetaminophen, and cotinine (Mahler et al. 2006, p. 64). The
presence of these contaminants in Barton Springs indicates the
vulnerability of salamander habitat to contaminant infiltration from
surface land uses.
Another study by the U.S. Geological Survey detected insecticides
(diazinon and malathion) and herbicides (atrazine, prometone, and
simazine) in several Austin-area streams, most often at sites with
urban and partly urban watersheds (Veenhuis and Slade 1990, pp. 45-47).
Twenty-two of the 42 selected synthetic organic compounds analyzed in
this study were detected more often and in larger concentrations at
sites with more urban watersheds compared to undeveloped watersheds
(Veenhuis and Slade 1990, p. 61). Other pesticides
(dichlorodiphenyltrichloroethane, chlordane, hexachlorobenzene, and
dieldrin) have been detected at multiple Jollyville Plateau salamander
sites (COA 2001, p. 130).
The frequency and duration of exposure to harmful levels of
pesticides have been largely unknown or undocumented for the four
central Texas salamander species. Therefore, we do not know the extent
to which pesticides and other waterborne contaminants have affected
salamander survival, development, and reproduction, or their prey to
date. However, pesticides are known to impact amphibian species in a
number of ways. For example, Reylea (2009, p. 370) demonstrated that
diazinon reduces growth and development in larval amphibians. Another
pesticide, carbaryl, causes mortality and deformities in larval
streamside salamanders (Ambystoma barbouri) (Rohr et al. 2003, p.
2,391). The Environmental Protection Agency (EPA) (2007a, p. 9) also
found that carbaryl is likely to adversely affect the Barton Springs
salamander both directly and indirectly through reduction of prey.
Additionally, atrazine has been shown to impair sexual development in
male amphibians at concentrations as low as 0.1 part per billion (Hayes
2002, p. 5,477). Atrazine levels were found to be greater than 0.44
part per billion after rainfall in Barton Springs Pool (Mahler and Van
Mere 2000, pp. 4, 12).
In summary, even though we do not know the extent to which
pesticides have affected the surface and subsurface habitat of the four
central Texas salamander species at this time, pesticides do pose a
significant, ongoing threat to the continued existence of all four
salamanders throughout their ranges.
Hazardous Material Spills
The Edwards Aquifer is at risk from a variety of sources of
pollutants (Ross 2011, p. 4), including hazardous materials that have
the potential to be spilled, resulting in contamination of both surface
and groundwater resources (Service 2005, pp. 1.6-14-1.6-15). Any
activity that involves the extraction, storage, manufacture, or
transport of potentially hazardous substances, such as fuels or
chemicals, can contaminate water resources and cause harm to aquatic
life. Spill events can involve a short release with immediate impacts,
such as a collision that involves a tanker truck carrying gasoline, or
the release can be long-term, involving the slow release of chemicals
over time such as a leaking underground storage tank. As of 1996, more
than 6,000 leaking underground storage tanks in Texas have resulted in
contaminated groundwater (Mace et al. 1997, p. 2), including a large
leak in the range of the Georgetown salamander (Mace et al, 1997, p.
32). The risk of this type of contamination is expected to increase
with increasing urbanization.
The transport of hazardous materials is common on many highways,
which are major transportation routes (Service 2005, p. 1.6-13).
Interstate Highway 35 crosses the watersheds that contribute
groundwater to spring sites known to be occupied by all four salamander
species. A catastrophic spill could occur if a transport truck
overturned and its contents entered the recharge zone of the Northern
Segment of the Edwards Aquifer. Transportation accidents involving
hazardous materials spills at bridge crossings are of particular
concern because recharge areas in creek beds can transport contaminants
directly into the aquifer (Service 2005, p. 1.6-14). Salado salamander
sites located downstream of Interstate Highway 35 may be particularly
vulnerable due to their proximity to this major transportation
corridor. Interstate Highway 35 crosses Salado Creek just 760 to 1,100
ft (231 to 335 m) from three spring sites (Big Boiling Springs, Lil'
Bubbly Springs, and Lazy Days Fish Farm) where the Salado salamander is
known to occur. Should a hazardous materials spill occur at the
Interstate Highway 35 bridge that crosses at Salado Creek, the Salado
salamander could be at risk from contaminants entering the water
flowing into its surface habitat downstream.
In addition, the Texas Department of Transportation (TxDOT) is
planning to reconstruct a section of Interstate Highway 35 within the
Village of Salado (Najvar, 2009, Service, pers. comm., p. 1). This work
will include replacing four bridges that cross Salado Creek (two main
lane bridges and two frontage road bridges) in an effort to widen the
highway at this location. This project could affect the risk of
hazardous materials spills and runoff into Salado Creek upstream of
known Salado
[[Page 50783]]
salamander locations. In August 2009, TxDOT began working with the
Service to identify measures, such as the installation of permanent
water quality control mechanisms to contain runoff, to protect the
Salado salamander and its habitat from the effects of this project
(Najvar 2009, pers. comm., p. 1).
Austin blind salamander habitat is similarly at risk from hazardous
material spills that could contaminate groundwater. There is potential
for a catastrophic gasoline spill in the Barton Springs Segment of the
Edwards Aquifer, due to the presence of the Longhorn pipeline (Turner
and O'Donnell 2004, pp. 2-3). Although a number of mitigation measures
were employed to reduce the risk of a leak or spill from the Longhorn
pipeline, such a spill could enter the aquifer and result in the
contamination of salamander habitat at Barton Springs (EPA 2000, pp. 9-
29-9-30).
Multiple water lines also run through the surrounding areas of
Barton Springs. A water line break could potentially flow directly into
Barton Springs, exposing salamanders to chlorine concentrations that
are potentially toxic (Herrington and Turner 2009, pp. 5, 6). Sewage
spills are the most common type of spill within the Barton Springs
watershed and represent a potential catastrophic threat (Turner and
O'Donnell 2004, p. 27). Sewage spills often include contaminants such
as nutrients, PAHs, metals, pesticides, pharmaceuticals, and high
levels of fecal coliform bacteria. Increased ammonia levels and reduced
dissolved oxygen are the most likely impacts of a sewage spill that
could cause rapid mortality of large numbers of salamanders (Turner and
O'Donnell 2004, p. 27). Fecal coliform bacteria cause diseases in
salamanders and their prey base (Turner and O'Donnell 2004, p. 27).
Approximately 7,600 wastewater mains totaling 349 mi (561.6 km) are
present in the Barton Springs Segment of the Edwards Aquifer
(Herrington et al. 2010, p. 16). In addition, there are 9,470 known
septic facilities in the Barton Springs Segment as of 2010 (Herrington
et al. 2010, p. 5), up from 4,806 septic systems in 1995 (COA 1995, p.
3-13). In one City of Austin survey of these septic systems, over 7
percent were identified as failing (COA 1995, p. 3-18).
A contaminant spill could travel quickly through the aquifer to
Barton Springs, where it could impact Austin blind salamander
populations. Depending on water levels in the aquifer, groundwater flow
rates through the Barton Springs Segment of the Edwards Aquifer can
range from 0.6 mi (1 km) per day to over 4 mi (6 km) per day. The
relatively rapid movement of groundwater under any flow conditions
provides little time for mitigation efforts to reduce potential damage
from a hazardous spill anywhere within the Barton Springs Segment of
the Edwards Aquifer (Turner and O'Donnell 2004, pp. 11-13).
A number of point-sources of pollutants exist within the Jollyville
Plateau salamander's range. Utility structures such as storage tanks or
pipelines (particularly gas and sewer lines) can accidentally
discharge. Leaking underground storage tanks have been documented as a
problem within the Jollyville Plateau salamander's range (COA 2001, p.
16). Sewage spills from pipelines also have been documented in
watersheds supporting Jollyville Plateau salamander populations (COA
2001, pp. 16, 21, 74). For example, in 2007, a sewage line overflowed
an estimated 50,000 gallons (190,000 liters) of raw sewage into the
Stillhouse Hollow drainage area of Bull Creek (COA 2007b, pp. 1-3). The
location of the spill was a short distance downstream of currently
known salamander locations, and no salamanders were thought to be
affected.
The City of Austin also cites swimming pools as a potential threat
to Eurycea salamanders if pools are drained into waterways or storm
drains without dechlorination (COA 2001, p. 130). This is due to the
concentrations of chlorine commonly used in residential swimming pools,
which far exceed the lethal concentrations observed in experiments with
the San Marcos salamander (Eurycea nana) (COA 2001, p. 130).
Residential swimming pools can be found throughout the watersheds of
several Jollyville Plateau salamander sites and may pose a risk to the
salamanders if discharged into the storm drain system or waterways.
Data on chemical spills near the City of Georgetown are lacking,
but the threat of groundwater contamination from accidental spills is
still present. As recently as 2011, a fuel tanker overturned in
Georgetown and spilled 3,500 gallons (13,249 liters) of gasoline
(McHenry et al. 2011, p. 1). A large plume of hydrocarbons was detected
within the Edwards Aquifer underneath Georgetown in 1997 (Mace et al,
1997, p. 32), probably the result of a leaking fuel storage tank. There
are currently eight water treatment plants within the city limits, with
wastewater and chlorinated drinking water lines running throughout
Georgetown salamander stream drainages (City of Georgetown 2008, p.
3.37). A ``massive'' wastewater line is being constructed in the South
San Gabriel River drainage (City of Georgetown 2008, p. 3.22), which is
within the watershed of one known Georgetown salamander site. Almost
700 septic systems were permitted or inspected in Georgetown in 2006
(City of Georgetown 2008, p. 3.36). Even though data on chemical spills
near the City of Georgetown are lacking, there is the potential for
spills and contamination to occur from multiple sources.
Several groundwater contamination incidents have occurred within
Salado salamander habitat (Price et al. 1999, p. 10). Big Boiling
Springs is located on the south bank of Salado Creek, near locations of
past contamination events (Chippindale et al. 2000, p. 43). Between
1989 and 1993, at least four incidents occurred within a quarter mile
(0.4 km) from the spring site, including a 700-gallon (2,650-liter) and
400-gallon (1,514-liter) gasoline spill and petroleum leaks from two
underground storage tanks (Price et al. 1999, p. 10). Because no
follow-up studies were conducted, we have no information to indicate
what effect these spills had on the species or its habitat. However,
between 1991 and 1998, only a single salamander was observed at Big
Boiling Springs (TPWD 2011a, p. 2).
In summary, catastrophic hazardous material spills pose a potential
significant threat to the Austin blind, Georgetown, and Salado
salamanders due to their restricted ranges. A significant hazardous
materials spill within a stream drainage for any of these species could
have the potential to threaten the long-term survival and
sustainability of multiple populations or possibly an entire species.
The threats from spills increase substantially under drought conditions
due to lower dilution and buffering capability of impacted waterbodies.
Spills under low flow conditions are predicted to have an impact at
much smaller volumes (Turner and O'Donnell 2004, p. 26). For example,
it is predicted that at low flows (10 cubic feet per second [cfs]) a
spill of 360 gallons (1,362.7 liters) of gasoline 3 miles (4.8 km) from
Barton Springs could be catastrophic for the Austin blind salamander
population (Turner and O'Donnell 2004, p. 26). Because the Austin blind
salamander resides in only one spring system, a catastrophic spill in
its surface and subsurface habitat could cause the extinction of this
species in the wild. However, because the Jollyville Plateau salamander
occurs in more populations over a broader range, the potential for a
catastrophic hazardous materials spill to affect the overall species'
status is small.
[[Page 50784]]
A hazardous materials spill has the potential to cause localized
populations to go extinct, but we do not consider this to be a threat
to the Jollyville Plateau salamander's overall continued existence.
But, in combination with the other threats identified in this five-
factor analysis, we think a catastrophic hazardous materials spill
could contribute to the species' risk of extinction by reducing its
long-term viability. We, therefore, consider hazardous material spills
to be a potential significant threat for the Austin blind and Salado
salamander due to their limited distributions. Hazardous material
spills are less of a threat for the more widespread Georgetown
salamander. These spills pose a low risk to the Jollyville Plateau
salamander due to its more widespread distribution.
Construction Activities
Short-term increases in pollutants, particularly sediments, can
occur during construction in areas of new development. When vegetation
is removed and rain falls on unprotected soils, large discharges of
suspended sediments can erode from newly exposed areas, resulting in
increased sedimentation in downstream drainage channels (Schueler 1987,
pp. 1-4; Turner 2003, p. 24; O'Donnell et al. 2005, p. 15). This
increased sedimentation from construction activities has been linked to
declines in Jollyville Plateau salamander counts at multiple sites
(Turner 2003, p. 24; O'Donnell et al. 2006, p. 34). Cave sites are also
impacted by construction, as Testudo Tube Cave (Jollyville Plateau
salamander habitat) showed an increase in nickel, calcium, and nitrate/
nitrite after nearby road construction (Richter 2009, pp. 6-7). Barton
Springs (Austin blind salamander habitat) is also under the threat of
pollutant loading due to its proximity to construction activities and
location at the downstream side of the watershed (COA 1997, p. 237).
The City of Austin (1995, p. 3-11) estimated that construction-related
sediment and in-channel erosion accounted for approximately 80 percent
of the average annual sediment load in the Barton Springs watershed. In
addition, the City of Austin (1995, p. 3-10) estimated that total
suspended sediment loads have increased 270 percent over pre-
development loadings within the Barton Springs Segment of the Edwards
Aquifer. At this time, we are not aware of any studies that have
examined sediment loading due to construction activities within the
watersheds of Georgetown or Salado salamander habitats. However,
because construction occurs in many of these watersheds, we believe
that the threat of construction in areas of new development applies to
these species as well. Construction is intermittent and temporary, but
it affects both surface and subsurface habitats. Therefore, we have
determined that this threat is ongoing and is and will continue to
affect the Austin blind, Jollyville Plateau, and Georgetown salamanders
and their habitats. However, we consider this threat to affect the
Salado salamander to a lesser degree due to the relatively low levels
of impervious cover in its range.
Also, the physical construction of pipelines has the potential to
modify subsurface habitat for salamander species. It is known that
these salamanders inhabit the subsurface environment. Tunneling for
underground pipelines can destroy potential habitat by removing
subsurface material. Additional material can become dislodged and
result in increased sediment loading into the aquifer and associated
spring systems. In addition, disruption of water flow to springs
inhabited by salamanders can occur through the construction of tunnels
and vertical shafts. Because detailed maps of the underground conduits
that feed springs in the Edwards Aquifer are not available, tunnels and
shafts have the possibility of intercepting and severing those conduits
(COA 2010b, p. 28). Affected springs could rapidly become dry and would
not support salamander populations. The closer a shaft or tunnel
location is to a spring, the more likely that the construction will
impact a spring (COA 2010b, p. 28). This has presumably occurred in the
past at Moss Gulley Spring, where the drilling of a nearby test well in
the mid-1980s led to the dewatering of the spring (Hillis et al. 2010,
p. 2). Jollyville Plateau salamanders have not been observed at that
site since the spring stopped flowing (Hillis et al. 2010, p. 2). Even
small shafts pose a threat to nearby spring systems, and therefore, we
consider construction of pipelines to be a future threat to the surface
and subsurface habitat of all four salamander species. However, we
consider this a low significance threat for the Jollyville Plateau
salamander because tunnels or shafts are likely to only impact a few
populations. Because there are currently no known projects that are
likely to occur within the species' range, we consider this a threat of
low significance for the Austin blind, Georgetown, and Salado
salamanders.
Likewise, we consider tunnel and shaft construction to be a threat
to the Jollyville Plateau salamander's surface and subsurface habitat
due to its potential to intercept groundwater flow and dewatering. In
2011, construction began on the Jollyville Transmission Main (JTM), a
tunnel designed to transport treated drinking water from Water
Treatment Plant No. 4 to the Jollyville Reservoir. The project also
includes four working shafts along the tunnel route (COA 2010b, p. 1).
Because the tunnel is being constructed below the Edwards Aquifer and
below the permeable portion of the Glen Rose formation (COA 2010b, p.
42; Toohey 2011, p. 1; COA 2011c, p. 36, 46), the threat to the
salamander from this particular tunnel is considered low. The vertical
shafts that are being drilled down through the Edwards Aquifer are a
more significant concern.
Of the four shafts, only the one at the Four Points location
appears to be a potential threat to any Jollyville Plateau salamanders.
The Parks and Recreation Department (PARD) shaft is in the Glen Rose
(not the Edwards) formation (Service 2010a; COA 2011c, p. 33) and
therefore is not expected to affect Edwards Aquifer groundwater. The
Jollyville Reservoir Shaft is on the other side of a groundwater divide
from any springs within a mile of the site (Service 2010a). The shaft
at the water treatment plant is going through a portion of the Edwards
formation that is dry (COA 2011c, p. 33). There are 8 of 92 known
Jollyville Plateau salamander sites within 1 mi (1.6 km) of the Four
Points shaft location. The closest locations (Spring 21 and Spring 24)
are about 2,000 ft (610 m) or greater from the shaft. Best management
practices designed to protect groundwater resources have been
implemented into the design and construction of the JTM shafts. These
practices include, but are not limited to: Monitoring groundwater
quality and spring flow, minimizing sediment discharges during
construction, developing a groundwater impact contingency plan,
locating working shafts in areas where the chance of encountering
conduits to salamander springs is reduced, and re-routing conduit flow
paths around the shaft if encountered (COA 2010b, pp. 51-55).
We believe that these best management practices have lowered the
magnitude of the threat to the Jollyville Plateau salamander. However,
a leak occurred at one shaft site (Four Points) in December 2011, and
it was associated with an initial 1-foot (0.3 m) drop in the aquifer
level (Toohey 2011, p. 2) as measured in a monitoring well 10 ft (3 m)
away. A 1-foot (0.3-m) drop in water level was also seen in a
monitoring well 100 ft (30 m) away, but not in
[[Page 50785]]
monitoring wells farther out. The City did not see any drops in flow at
the springs they were monitoring or in wells between those springs and
the well 100 ft away; however, they do not have access to the closest
springs (mentioned above). Since that time, grout has been injected
into the shaft wall to stop the leak. Preliminary evidence indicates
that the grout injection resulted in a tight seal at the site of the
leak (Lesniak 2012, City of Austin, pers. comm.). Even so, we consider
tunnel and shaft construction of the JTM to be a threat now to the
Jollyville Plateau salamander's habitat due to its potential to
intercept groundwater flow and to dewater; however, we consider this
threat to be of low significance because the best management practices
have been implemented into the design and construction of the JTM
shafts to protect groundwater resources.
Lastly, limestone rock is an important raw material that is mined
in quarries all over the world due to its popularity as a building
material and its use in the manufacture of cement (Vermeulen and
Whitten 1999, p. 1). The construction activities within rock quarries
can permanently alter the geology and groundwater hydrology of the
immediate area, and adversely affect springs that are hydrologically
connected to impacted sites. The potential environmental impacts of
quarries include outright destruction of springs or collapse of karst
caverns, as well as impacts to water quality through siltation and
sedimentation, and impacts to water quantity through water diversion,
dewatering, and reduced flows (Ekmekci 1990, p. 4). Limestone is a
common geologic feature of the Edwards Aquifer, and active quarries
exist throughout the region. For example, at least three Georgetown
salamander sites (Avant Spring, Knight (Crockett Gardens) Spring, and
Cedar Breaks Hiking Trail Spring) occur adjacent to a limestone quarry
that has been active since at least 1995. The population status of the
Georgetown salamander is unknown at Knight Spring and Cedar Breaks
Hiking Trail Spring, but salamanders are seen infrequently and in low
abundance at the closest spring to the quarry (Avant Spring; Pierce
2011c, pers. comm.). Because quarries may only affect a small portion
of the species' ranges, we consider the mining of limestock rock to be
an ongoing threat with limited effect to the Georgetown, Jollyville
Plateau, and Salado salamanders, but not the Austin blind salamander.
The Austin blind salamander's range is located in downtown Austin, and
there are no active limestone quarries within the species' range.
Water Quantity Reduction in Relation to Urbanization
The Northern Segment of the Edwards Aquifer is the primary supply
of water for Jollyville Plateau, Georgetown, and Salado salamander
habitat (Cole 1995, p. 33; TPWD 2011a, p. 3). In general, the aquifer
has been described as localized, small, and highly susceptible to
drying or draining (Chippindale et al. 2000, p. 36).
Urbanization and rapid population growth in the Northern Segment of
the Edwards Aquifer may contribute to reduced spring flows due to
increases in groundwater pumping. From 1980 to 2000, groundwater
pumping in the Northern Segment of the Edwards Aquifer nearly doubled
(TWDB 2003, pp. 32-33). The City of Georgetown predicts the average
water demand to increase from 8.21 million gallons per day in 2003, to
10.9 million gallons per day by 2030 (City of Georgetown 2008, p.
3.36). Under peak flow demands (18 million gallons per day in 2003),
the City of Georgetown uses seven groundwater wells in the Edwards
Aquifer (City of Georgetown 2008, p. 3.36). Total water use for
Williamson County was 73,532 ac ft in 2010, and is projected to
increase to 98,268 ac ft by 2020, and to 211,854 ac ft by 2060,
representing a 188 percent increase over the 50-year period (TWDB 2010,
p. 46). Similarly, Bell County and Travis County expect a 59 percent
and 91 percent increase in total water use over the same 50-year
period, respectively (TWDB 2010, pp. 46, 64).
One prediction of future groundwater use in this area suggests a
large drop in pumping as municipalities convert from groundwater to
surface water supplies (TWDB 2003, p. 65). However, it is unknown if
this reduction in groundwater use translates to adequate spring flows
for salamanders. Increased urbanization in the watershed has been cited
as one factor, in combination with drought, causing declines in spring
flows (City of Austin 2006, pp. 46-47; TPWD 2011a, pp. 4-5).
Urbanization removes the ability of the watershed to allow slow
filtration of water through soils following rain events. Instead
rainfall runs off impervious surfaces and into stream channels at
higher rates, increasing downstream flows and decreasing groundwater
recharge (Miller et al. 2007, p. 74).
The City of Austin found a negative correlation between
urbanization and spring flows at Jollyville Plateau salamander sites
(Turner 2003, p. 11). Field studies have also shown that a number of
springs that support Jollyville Plateau salamanders have already gone
dry periodically, and that spring waters resurface following rain
events (O'Donnell et al. 2006, pp. 46-47). The San Gabriel Springs
(Georgetown salamander habitat) are now intermittently flowing in the
summer due to pumping from nearby water wells (TPWD 2011a, p. 9).
Salamanders have not been seen on the surface there since 1991
(Chippindale et al. 2000, p. 40; Pierce 2011b, pers. comm.).
In combination with drought, groundwater pumping has a direct
impact on spring flows. Groundwater availability models demonstrate
that 1 cfs of pumping will diminish Barton Springs spring flow by 1 cfs
under drought-of-record (1950s drought) conditions (Smith and Hunt
2004, pp. 24, 36). Under the same conditions, these models suggest that
present-day pumping rates will temporarily cease Barton Springs flow on
a daily basis (Smith and Hunt 2004, pp. 24, 36).
Groundwater pumping can lead to saline water encroachments in the
aquifer. As groundwater levels decline, a decrease in hydrostatic
pressure occurs and saline groundwater is able to penetrate up into the
lower portion of the aquifer (Pavlicek et al. 1987, p. 2). This saline
water encroachment would threaten the freshwater biota in the springs
and the aquifer, including the four central Texas salamander species
and their prey, by dramatically increasing the water salinity. Water
quality in the Barton Springs Segment of the Edwards Aquifer has been
degraded in the past due to saline encroachment (Slade et al. 1986, p.
62). This water quality degradation occurred when Barton Springs
discharge was less than 30 cfs (Slade et al. 1986, p. 64). An analysis
of more recent data found similar declines in water quality as the flow
of Barton Springs dropped into the 20 to 30 cfs range (Johns 2006, pp.
6-7). As mentioned earlier, reduced groundwater levels would also
increase the concentration of pollutants in the aquifer. Flows at
Barton Springs dropped below 17 cfs as recently as mid-November 2011
(Barton Springs/Edwards Aquifer Conservation District 2011, p. 1).
Although water quantity decreases and spring flow declines are
cited as a threat to Eurycea salamanders (Corn et al. 2003, p. 36;
Bowles et al. 2006, p. 111), these species display some adaptive
behavior to deal with periods of periodic surface flow losses. All four
salamander species apparently spend some part of their life history in
underground aquatic habitats and have the ability to retreat
underground when
[[Page 50786]]
surface flows decline. For example, one of the City of Austin
monitoring sites where Jollyville Plateau salamanders are most abundant
undergoes periods where there is no surface water habitat available for
the salamander (O'Donnell et al. 2006, p. 47). Jollyville Plateau
salamander juveniles were observed at Lanier Spring following 10 months
of dry conditions on the surface, indicating that the salamanders are
likely able to reproduce in the subsurface environment during a drought
(Bendik 2011a, p. 32). Salado salamanders also reappeared in Robertson
Springs after the springs went temporarily dry in 2009 (TPWD 2011a, p.
5). However, drying spring habitats can result in stranding
salamanders, resulting in death of individuals (O'Donnell et al. 2006,
p. 16). It is also known that prey availability for carnivores is low
underground due to the lack of primary production (Hobbs and Culver
2009, p. 392). This is supported by recent evidence of ``shrinkage'' in
Jollyville Plateau salamander body length following periods of no
springflow (Bendik 2011b, pers. comm.). Length measurements taken
during a COA mark-recapture study at Lanier Spring demonstrated that
Jollyville Plateau salamanders had negative growth during a 10-month
period of no springflow in 2008-2009 (Bendik 2011b, pers. comm.).
Therefore, although central Texas salamanders can survive and reproduce
underground, the best available scientific evidence shows that these
animals need the energy-rich surface habitat for positive growth and
development.
In summary, water quantity reduction in relation to urbanization is
an ongoing threat to all four salamanders throughout their ranges,
primarily due to increased groundwater pumping in the presence of
drought conditions and potential increases in saline water
encroachments in the aquifer. However, we believe this threat is having
or likely to have only a moderate effect, because the salamanders have
the ability to retreat underground when surface flows decline.
Physical Modification of Surface Habitat
All four salamanders are sensitive to direct physical modification
of surface habitat from impoundments, feral hogs, livestock, and other
human activities. Because these threats only impact the surface habitat
of salamanders, and because each species has the ability to retreat to
subsurface habitats for shelter, none of these threats is likely to
result in a significant impact to the species or their habitat.
However, in combination with other threats discussed above, these
threats may contribute to the species' risk of extinction.
Impoundments
Impoundments disrupt the natural flow regime of streams, leading to
a variety of stressors that impact the salamanders and their surface
habitats. For example, a low water crossing on a tributary of Bull
Creek, occupied by the Jollyville Plateau salamander, resulted in
sediment build-up below the impoundment and a scour hole above the
impoundment that supported predaceous fish (O'Donnell et al. 2008, p.
1). As a result, Jollyville Plateau salamanders were not found in this
degraded habitat after the impoundment was constructed. When the
crossing was removed in October 2008, the sediment build-up was
removed, the scour hole was filled, and salamanders were later observed
(Bendik 2011b, pers. comm.). Many low-water crossings are present near
other Jollyville Plateau salamander sites (Bendik 2011b, pers. comm.).
Impoundments only impact the surface habitat of salamanders. Because
impoundments are likely to impact a small portion of the species'
range, we consider impoundments caused by low-water crossings to be an
ongoing threat of limited effect on the Jollyville Plateau salamander
and its surface habitat, now and in the future.
Impoundments have also impacted surface habitat for the other
salamander species. Most of the spring outlets in the Village of
Salado, including the Salado salamander type locality at Big Boiling
Springs, were modified by dam construction in the mid-1800s, to supply
power to various mills (Brune 1981, p. 67). Two sites for the
Georgetown salamander have spring openings that are confined to brick
and mortar spring boxes (White 2011, SWCA, pers. comm.; Booker 2011, p.
1), presumably to collect the spring water for cattle. All spring sites
for the Austin blind salamander (Main, Eliza, and Sunken Garden
springs) have been impounded for recreational use. These sites were
impounded in the early to mid-1900s. For example, Eliza Spring now
discharges from 7 openings (each 1 ft (0.3 m) in diameter) in the
concrete floor and 13 rectangular vents along the edges of the
concrete. While the manmade structures help retain water in the spring
pools during low flows, they have altered the salamander's natural
environment. The impoundments have changed the Barton Springs ecosystem
from a stream-like system to a more lentic (still water) environment,
thereby reducing the water system's ability to flush sediments
downstream and out of salamander habitat. Although a natural surface
flow connection between Sunken Gardens Spring and Barton Creek has been
restored recently (COA 2007c, p. 6), the Barton Springs system as a
whole remains highly modified. Therefore, we consider impoundments to
be an ongoing threat to the Salado, Georgetown, and Austin blind
salamanders and their surface habitat, now and in the future. This
threat has a limited effect on the Salado and Georgetown salamanders
because it impacts a small portion of the species' ranges, but has a
large effect on the Austin blind salamander because it affects this
species' entire range.
Feral Hogs
There are between 1.8 and 3.4 million feral hogs (Sus scrofa) in
Texas (TAMU 2011, p. 2). They prefer to live around moist areas,
including riparian areas near streams, where they can dig into the soft
ground for food and wallow in mud to keep cool (Mapson 2004, pp. 11,
14-15). Feral hogs disrupt these ecosystems by decreasing plant species
diversity, increasing invasive species abundance, increasing soil
nitrogen, and exposing bare ground (Texas A&M University (TAMU) 2012,
p. 4). Feral hogs negatively impact surface salamander habitat by
digging and wallowing in spring heads, which increases sedimentation
downstream (O'Donnell et al. 2006, pp. 34, 46). They have been cited as
a source of elevated bacteria, nitrates, and phosphorus to streams in
the Austin area (Timmons et al. 2011, pp. 1-2).
Feral hogs have become abundant in some areas where the Jollyville
Plateau, Georgetown, and Salado salamanders occur. O'Donnell et al.
(2006, p. 34) noted that feral hog activity was increasing in the Bull
and Cypress creek watersheds. Evidence of hogs has also been observed
near one Georgetown salamander site (Cobbs Spring) (Booker 2011, p. 1).
The landowner of Cobbs Spring is actively trapping feral hogs (Booker
2011, p. 1), but the effectiveness of this management has not been
assessed. Feral hogs are also present in the area of several Salado
salamander sites. Fortunately, feral hogs cannot access Austin blind
salamander sites due to fencing and their location in downtown Austin.
In summary, because of their abundance and potential to negatively
impact surface salamander habitat, we consider feral hogs to be an
ongoing threat of low significance to the Jollyville Plateau,
Georgetown, and Salado salamanders. As previously stated, we do not
consider feral hogs to
[[Page 50787]]
be a threat to the Austin blind salamander at this time.
Livestock
Similar to feral hogs, livestock can negatively impact surface
salamander habitat by disturbing the substrate and increasing
sedimentation in the spring run where salamanders are often found.
Poorly managed livestock grazing results in changes in vegetation (from
grass-dominated to brush-dominated), which leads to increased erosion
of the soil profile (COA 1995, p. 3-59). Grazing near streams can
negatively impact nutrients, bacteria, species diversity, and water
temperature in stream systems (COA 1995, p. 3-62). Evidence of
trampling and grazing in riparian areas from cattle can be found at one
Georgetown salamander site (White 2011, SWCA, pers. comm.), and cattle
are present on at least one other Georgetown salamander site. Cattle
are also present on lands where four Salado salamander sites occur
(Gluesenkamp 2011b, pers. comm.; Texas Section Society for Range
Management 2011, p. 2). Austin blind salamander habitat is inside a
City of Austin park, and livestock are not allowed in the spring areas.
Much of the Jollyville Plateau salamander habitat is in suburban areas,
and we are not aware of livestock damage in those areas.
There is some management of livestock occurring that reduces the
magnitude of negative impacts. An 8,126-ac (3,288-ha) property in Bell
County with at least three Salado salamander sites has limited its
cattle rotation to a maximum of 450 head (Texas Section Society for
Range Management 2011, p. 2), which is considered a moderate stocking
rate. The landowners at four of the springs with Salado salamanders
have been considering options for fencing off spring outlets to protect
the salamander habitat from cattle damage (Harrell 2012, Service, pers.
comm.). In addition, the landowner of Cobbs Spring (a Georgetown
salamander site) is in the process of phasing out cattle on the
property (Boyd 2011, Williamson County Conservation Foundation, pers.
comm.).
In summary, even though livestock may be having impacts at four of
the seven Salado salamander spring sites, we believe livestock to be an
ongoing threat of low impact to this salamander's habitat because there
is some management of the livestock that reduces the magnitude of
negative impacts. Even though habitat degradation by livestock is a
factor that seems to be impacting the habitat of the Georgetown
salamander, we do not believe it is occurring at a scale that
significantly contributes to the risk of extinction of the species on
its own. However, in combination with the other threats identified in
this five-factor analysis, we think livestock may be contributing to
the species' risk of extinction by reducing its long-term viability.
Livestock are not a threat to the continued existence of the Austin
blind or Jollyville Plateau salamanders.
Other Human Activities
Some sites for the four central Texas salamanders have been
directly modified by human-related activities. In the summer of 2008, a
spring opening at a Salado salamander site was covered with gravel
(Service 2010b, p. 6). Although we received anecdotal information that
at least one salamander was observed at the site after the gravel was
dumped at Big Boiling Springs, the Service has no detailed information
on how the Salado salamander was affected by this action. Heavy
machinery is continuously used in the riparian area of Big Boiling and
Lil' Bubbly Springs to clear out vegetation and maintain a grassy lawn
to the water's edge (Gluesenkamp 2011a,b, pers. comm.), which has led
to erosion problems during flood events (TPWD 2011a, p. 6). The
modification of springs for recreation or other purposes degrades
natural riparian areas, which are important for controlling erosion and
attenuating floodwaters in aquatic habitats. Other continuing human
activities at Big Boiling Spring include pumping water from the spring
opening, contouring the substrate of the spring environment, and
covering spring openings with gravel (TPWD 2011a, p. 4). For example,
in the fall of 2011, the outflow channels and edges of these two
springs were reconstructed with large limestone blocks and mortar. In
addition, in response to other activity in the area, the U.S. Army
Corps of Engineers issued a cease and desist order to the Salado
Chamber of Commerce in October 2011, for unauthorized discharge of
dredged or fill material that occurred in this area (Brooks 2011, U.S.
Corps of Engineers, pers. comm.). This order was issued in relation to
the need for a section 404 permit under the Clean Water Act (33 U.S.C.
1251 et seq.). Also in October 2011, a TPWD game warden issued a
citation to the Salado Chamber of Commerce due to the need for a sand
and gravel permit from the TPWD for work being conducted within TPWD's
jurisdiction (Heger 2012a, TPWD, pers. comm.). The citation was issued
because the Salado Chamber of Commerce had been directed by the game
warden to stop work within TPWD's jurisdiction, which Salado Chamber of
Commerce did temporarily, but work started again in spite of the game
warden's directive (Heger 2012a, pers. comm.). A sand and gravel permit
was obtained on March 21, 2012. The spring run modifications were
already completed by this date, but further modifications in the
springs were prohibited by the permit. Additional work on the bank
upstream of the springs was permitted and completed (Heger 2012b, pers.
comm.).
Because the Salado salamander is only known from seven spring
locations, any type of human-related activities, such as pumping water
from a spring opening, contouring the substrate of a spring
environment, and covering spring openings with gravel, may have
significant detrimental effects on the salamander and its habitat.
These activities only affect the surface salamander habitat. Therefore,
we consider these types of human-related activities to be ongoing
threats of low impact to the Salado salamander's continued existence.
Furthermore, frequent human visitation associated with easily
accessed habitat of the four salamanders may negatively affect the
species and their habitat. Documentation from the City of Austin of
disturbed vegetation, vandalism, and the destruction of travertine
deposits (fragile rock formations formed by deposit of calcium
carbonate on stream bottoms) by foot traffic has been documented at one
of their Jollyville Plateau salamander monitoring sites in the Bull
Creek watershed (COA 2001, p. 21) and may result in direct destruction
of small amounts of the salamander's habitat. Eliza Spring and Sunken
Garden Spring, two of the three locations of the Austin blind
salamander, also experience vandalism, despite the presence of fencing
and signage (Dries 2011, City of Austin, pers. comm.). The deep water
of the third location (Main Pool) likely protects the Austin blind
salamander's surface habitat from damage from frequent human
recreation. Therefore, we consider human visitation to be an ongoing
threat of low impact to the Jollyville Plateau salamander, and a threat
of moderate impact to the Austin blind salamander, now and in the
future.
Lastly, at the complex of springs occupied by the Georgetown
salamander within San Gabriel River Park, a thick bed of nonnative
granite gravel has been placed in the spring runs (TPWD 2011a, p. 9).
This pea gravel is too small to serve as cover habitat and does not
form the interstitial spaces required for
[[Page 50788]]
Georgetown salamanders. Salamanders have not been observed here since
1991 (Chippindale et al. 2000, p. 40; Pierce 2011b, pers. comm.).
Gravel dumping has not been documented at any other Georgetown
salamander sites. Because this activity may have contributed to the
decline of only this single population, we do not consider substrate
modification in the form of gravel dumping to be a threat to the
existence of the Georgetown salamander by itself. However, in
combination with the other threats identified in this five-factor
analysis, we think substrate modification may be contributing to the
species' risk of extinction by reducing its long-term viability.
Drought and Flooding
Broad drought and flooding events have proven to have large impacts
on the central Texas salamanders by drastically reducing or increasing
the amount of water and affecting habitat quality.
Drought
The presence of water is an essential component to salamander
habitat. Drought conditions alter the hydrologic conditions resulting
in lowering groundwater tables and reduced spring flows. The impacts of
drought are compounded by other consumptive uses of the aquifer such as
groundwater pumping. The Northern Segment of the Edwards Aquifer, which
supplies water to Jollyville Plateau, Georgetown, and Salado salamander
habitat, is vulnerable to drought (Chippindale et al. 2000, p. 36). In
particular, the portion of the Edwards Aquifer underlying the
Jollyville Plateau is relatively shallow, with a high elevation, thus
being unlikely to be able to sustain spring flows during periods of
drought (Cole 1995, pp. 26-27). Drought in the watershed has been cited
as one factor, in combination with urbanization, causing declines in
spring flows (O'Donnell et al. 2006, pp. 46-47). A recent drought
lasting from 2008 to 2009 was considered one of the worst droughts in
central Texas history and caused numerous Jollyville Plateau salamander
sites to go dry (Bendik 2011a, p. 31). An even more pronounced drought
throughout Texas began in 2010, with the period from October 2010,
through September 2011, being the driest 12-month period in Texas since
rainfall records began (LCRA 2011, p. 1). Rainfall in early 2012 has
lessened the intensity of the current drought, but below average
rainfall and above average temperatures are forecasted for the summer
of 2012 (LCRA 2012, p. 1).
Low flow conditions during drought also have negative impacts to
the Austin blind salamander and its ecosystem in the Edwards Aquifer
and at Barton Springs. The long-term average flow at the Barton Springs
outlets is approximately 53 cfs (City of Austin 1998, p. 13; Smith and
Hunt 2004, p. 10). The lowest flow recorded at Barton Springs was about
10 cfs during a record drought in the 1950s (COA 1998, p. 13).
Discharge at Barton Springs decreases as water levels in the Barton
Springs Segment of the Edwards Aquifer drop. Decreased discharge is
associated with increases in water temperature, decreases in spring
flow speed, and increases in sedimentation (COA 2011d, pp. 19, 24, 27).
Large declines in aquifer levels have historically been due to a lack
of adequate rainfall recharging the aquifer. In a 2004 groundwater flow
modeling study, the Barton Springs Edwards Aquifer Conservation
District predicted that under drought-of-record conditions and current
pumping levels, the mean monthly springflow would be about 1 cfs. This
study also indicated that under drought-of-record conditions, projected
pumping rates for future years would cause Barton Springs to cease
flowing for at least 4 months out of a year (Smith and Hunt 2004, pp.
1, 20, 24).
The specific effects of low flow on central Texas salamanders can
be inferred by examining studies on the Barton Springs salamander.
Drought decreases spring flow and dissolved oxygen levels and increases
temperature in Barton Springs (Turner 2004, p. 2; Turner 2009, p. 14).
Low dissolved oxygen levels decrease reproduction in Barton Springs
salamanders (Turner 2004, p. 6; 2009, p. 14). Turner (2009, p. 14) also
found that Barton Springs salamander counts decline with decreasing
discharge (and thus declining dissolved oxygen levels). A prolonged
drought from June 2008 through September 2009 caused decreases in
Barton Springs salamander abundance (COA 2011d, pp. 19, 24, 27). The
drought in 2011 resulted in dissolved oxygen concentrations so low that
City of Austin used an aeration system to maintain oxygenated water in
Eliza and Sunken Gardens Springs (Dries 2011, City of Austin, pers.
comm.). Drought also lowers water quality in Barton Springs due to
saline water encroachments in the Barton Springs Segment of the Edwards
Aquifer (Slade et al. 1986, p. 62; Johns 2006, p. 8).
In summary, we consider drought to be an ongoing threat to all four
salamanders, because it can cause direct mortality to salamanders by
desiccation if they are unable to retreat underground, it increases
competition for spaces and resources (Bendik 2011a, p. 31), and it
negatively affects their habitat, as discussed above. However, we
consider the threat of drought to have a limited impact to all four
central Texas salamanders and their habitats because they may be
evolutionarily adapted to drought conditions that are common to the
region (Bendik 2011a, pp. 31-32). At the same time, climate change and
groundwater pumping may exacerbate drought conditions to the point
where salamanders cannot adapt (see ``Climate Change'', below, and
``Water Quantity Reduction in Relation to Urbanization'', above).
Flooding
Flooding as a result of rainfall events can dramatically alter the
substrate and hydrology of salamander habitat. A flood event in
September 2010 modified surface habitat for the Georgetown salamander
at two sites (Pierce 2011a, p. 10). The stormwater runoff caused
erosion, scouring of the streambed channel, the loss of large rocks,
and the creation of several deep pools. Salamander densities dropped
dramatically in the days following the flood, and at one site, remained
at low levels until habitat restoration (returning large rocks to the
spring run) took place in the spring of 2011 (Pierce 2011a, p. 11).
Likewise, three storm events in 2009 and 2010 deposited sediment and
other material on top of spring openings at Salado Spring, preventing
salamanders from foraging (TPWD 2011a, p. 6). The increased flow rate
from flooding causes unusually high dissolved oxygen concentrations,
which may exert direct or indirect, sub-lethal effects (reduced
reproduction or foraging success) on salamanders (Turner 2009, p. 11).
In addition, Geismar (2005, p. 2) found that flooding increases
contaminants and sediments in Barton Springs. In 2007, flooding
resulted in repeated accumulation of sediment in the Main Pool of
Barton Springs that was so rapid that cleaning by City of Austin staff
was not frequent enough to keep the surface habitat from becoming
embedded (COA 2007c, p. 4). Flooding likely has similar effects on
contaminants and sediments in other salamander habitat, but we are not
aware of other studies.
The four salamanders' surface habitat is characterized by shallow
water depth (COA 2001, p. 128; Pierce 2011a, p. 3), but deep pools are
sometimes formed within stream channels from the scouring of floods.
Tumlison et al. (1990, p. 172) found that the abundance of one Eurycea
species decreased as
[[Page 50789]]
water depth increased. This relationship may be caused by an increase
in predation pressure, as deeper water supports predaceous fish
populations. However, several central Texas Eurycea species are able to
thrive in deep water environments in the presence of many predators
(for example, San Marcos salamander in Spring Lake, Eurycea sp. in
Landa Lake, Barton Springs salamander in Barton Springs Pool). Anti-
predator behaviors may allow these species to co-exist with predaceous
fish, and the effectiveness of these behaviors may be species-specific
(reviewed in Pierce and Wall 2011, pp. 18-19). The specific resistance
to predation from fish for the four central Texas salamanders is
unknown. In any case, flooding can alter the surface habitat by
deepening stream channels, which may increase predaceous fish.
Also, salamanders may be flushed from the surface habitat by strong
flows during flooding. Bowles et al. (2006, p. 117) observed no
Jollyville Plateau salamanders in riffle habitat at one site during
high water velocities and hypothesized that individual salamanders were
either flushed downstream or retreated to the subsurface. This site had
a relatively undeveloped watershed (Bowles et al. 2006, p. 112),
indicating that the runoff was largely natural and not caused by
impervious cover.
In conclusion, flooding is a naturally occurring event that all
four salamander species have adapted to in the past. Further, even
though flooding is a factor that seems to be impacting all four
salamanders' surface habitats, we do not believe it is occurring at a
scale that would cause the extinction of any of the salamanders on its
own. Because of this, we consider flooding on its own to have a limited
effect on the species and their habitats. However, in combination with
the other threats identified in this five-factor analysis, we think
flooding may be contributing to the species' risk of extinction by
reducing its long-term viability. The intensity of flooding events has
increased due to increases in impervious cover. As previously noted,
once natural vegetation in a watershed is replaced with impervious
cover, rainfall is converted to surface runoff instead of filtering
through the ground (Schueler 1991, p. 114). Impervious cover in a
stream's watershed causes streamflow to shift from predominately
baseflow, which is derived from natural filtration processes and
discharges from local groundwater supplies, to predominately stormwater
runoff. With increasing stormwater runoff, the amount of baseflow
available to sustain water supplies during drought cycles is diminished
and the frequency and severity of flooding increases. Because of the
detrimental effects previously discussed in association with increased
stormwater runoff, we consider changes in flow regime due to impervious
cover to be an ongoing threat to all four central Texas salamanders'
surface habitats.
Climate Change
Future climate change could potentially affect water quantity and
spring flow for the four salamander species. According to the
Intergovernmental Panel on Climate Change (IPCC 2007, p. 1), ``warming
of the climate system is unequivocal, as is now evident from
observations of increases in global averages of air and ocean
temperatures, widespread melting of snow and ice, and rising global
average sea level.'' Localized projections suggest the southwest United
States may experience the greatest temperature increase of any area in
the lower 48 States (IPCC 2007, p. 8), with warming increases in
southwestern States greatest in the summer. The IPCC also predicts hot
extremes, heat waves, and heavy precipitation will increase in
frequency (IPCC 2007, p. 8).
Climate change could compound the threat of decreased water
quantity at salamander spring sites. An increased risk of drought could
occur if evaporation exceeds precipitation levels in a particular
region due to increased greenhouse gases in the atmosphere (CH2M HILL
2007, p. 18). The Edwards Aquifer is also predicted to experience
additional stress from climate change that could lead to decreased
recharge and low or ceased springflows given increasing pumping demands
(Lo[aacute]iciga et al. 2000, pp. 192-193). CH2M HILL (2007, pp. 22-23)
identified possible effects of climate change on water resources within
the Lower Colorado River Watershed (which contributes recharge to
Barton Springs). A reduction of recharge to aquifers and a greater
likelihood for more extreme droughts were identified as potential
impacts to water resources (CH2M HILL 2007, p. 23). The droughts of
2008 to 2009, and 2010 to 2011, were two of the worst in central Texas
history, with the period from October 2010, through September 2011,
being the driest 12-month period in Texas since rainfall records began
(LCRA 2011, p. 1). Rainfall in early 2012 has lessened the intensity of
the current drought, but below average rainfall and above average
temperatures are forecasted for the summer of 2012 (LCRA 2012, p. 1).
In summary, the effects of climate change could potentially lead to
detrimental impacts on aquifer-dependent species, especially coupled
with other threats on water quality and quantity. However, there are
little data available to correlate groundwater trends and climate
change, and groundwater typically represents an integration of past
climatic conditions over many years due to its time within an aquifer
system (Mace and Wade 2008, p. 657). Recharge, pumping, natural
discharge, and saline intrusion of groundwater systems could all be
affected by climate change (Mace and Wade 2008, p. 657). Because
climate change has the potential to negatively affect water quality and
spring flow, we consider climate change to be a potential threat to all
four central Texas salamanders and their habitats, now and in the
future.
Land Conservation Programs and Plans
The Williamson County Conservation Foundation (Foundation), a
nonprofit organization established by Williamson County in 2002, is
currently working to find ways to conserve endangered species and other
unlisted species of concern in Williamson County, Texas. This
organization held a Georgetown salamander workshop in November 2003, in
an effort to bring together landowners, ranchers, farmers, developers,
local and State officials, Federal agencies, and biologists to discuss
information currently known about the Georgetown salamander and to
educate the public on the threats faced by this species.
With the help of a grant funded through section 6 of the Act, the
Foundation developed the Williamson County Regional HCP to obtain a
section 10(a)(1)(B) permit for incidental take of federally listed
endangered species in Williamson County, Texas. This HCP became final
in October 2008. Although the Georgetown salamander is not currently
listed and is not a ``covered'' species, the Foundation has included
considerations for the Georgetown salamander in the HCP. In particular,
they plan to conduct a status review of the Georgetown salamander. The
Foundation plans to fund at least $50,000 per year for 5 years for
monitoring, surveying, and gathering baseline data on water quality and
quantity at salamander spring sites. Information gathered during this
status review will be used to develop a conservation strategy for this
species. The Foundation began allocating funding for Georgetown
salamander research and monitoring beginning in 2010. A portion of that
funding supported mark-recapture studies of the Georgetown salamander
at two of its
[[Page 50790]]
known localities (Twin Springs and Swinbank Spring) in 2010 and 2011
(Pierce 2011a, p. 20). Additional funds have been directed at water
quality assessments of at least two known localities and efforts to
find previously undiscovered Georgetown salamander populations (Boyd
2011, pers. comm.). Although Jollyville Plateau salamanders are present
in southwest Williamson County and Salado salamander spring sites are
likely influenced by the Edwards Aquifer Recharge Zone in northern
Williamson County, the regional HCP does not include considerations for
these species. Also, Austin blind salamanders are not affected by this
HCP.
Although the Service worked with the Foundation to develop the
regional HCP for several listed karst invertebrates, it is also
expected to benefit the Georgetown salamander by lessening the
potential for water quality degradation within the spring systems it
inhabits. As part of this HCP, the Foundation is looking to set aside
land that is beneficial to karst invertebrate species. Some of these
lands are in areas that will also provide water quality benefits for
the Georgetown salamander. For example, the Foundation has purchased an
easement on the 64.4-ac (26.1-ha) Lyda tract (Cobbs Cavern) in
Williamson County through the section 6 grant program. This section 6
grant was awarded for the protection of listed karst invertebrate
species; however, protecting this land also benefited the Georgetown
salamander. Although the spring where salamanders are located was not
included in the easement, a portion of the contributing watershed for
this spring was included. For this reason, some water quality benefits
to the salamander are expected. In January 2008, the Foundation also
purchased the 145-ac (59-ha) Twin Springs preserve area. This tract is
one of the sites known to be occupied by Georgetown salamanders.
Despite the conservation efforts of the Foundation, the Georgetown
salamander faces ongoing threats due to the lack of habitat protection
outside of these preserves. This species is limited to 16 known
localities, of which only three (Cobbs Spring, Cobbs Well, and Twin
Springs) have some amount of protection by the Foundation. The
population size of Georgetown salamanders at Cobbs Spring is unknown,
while the population size at Twin Springs is estimated to be only 100
to 200 individuals (Pierce 2011a, p. 18). Furthermore, the watershed of
Cobbs Spring is currently only partially protected by the Foundation.
The Balcones Canyonlands Preserve offers some water quality
benefits to the Jollyville Plateau salamander in portions of the Bull
Creek, Brushy Creek, Cypress Creek, and Long Hollow Creek drainages
through preservation of open space (Service 1996a, pp. 2-28, 2-29).
However, eight of the nine City of Austin monitoring sites occupied by
the Jollyville Plateau salamander within the Balcones Canyonlands
Preserve have experienced water quality degradation occurring upstream
and outside of the preserved tracts (O'Donnell et al. 2006, pp. 29, 34,
37, 49; COA 1999, pp. 6-11; Travis County 2007, p. 4). Additionally,
Jollyville Plateau salamanders are not a covered species under the
section 10(a)(1)(B) permit under which the preserves were established
(Service 1996b, pp. 1-10). Therefore, they receive no specific
protections under the Balcones Canyonlands Preserve permit, such as
mitigation to offset impacts from development.
The landowners of one 8,126-ac (3,288-ha) property with at least
three high-quality Salado salamander sites and the landowner of another
property with one Salado salamander site have shown a commitment to
natural resource conservation and land stewardship practices that
benefit the Salado salamander. Neither ranch owner has immediate plans
to develop their land, which means that the Salado salamander is
currently not faced with threats from urbanization (see discussion
above under Factor A) from these lands. However, only 21 percent of the
watershed is contained within the property with three Salado salamander
sites, and only 3 percent of the watershed is contained within the
other property with the one Salado salamander site. The remaining area
of the watersheds and the recharge zone for these springs is not
contained within the properties and is not protected from future
development. Considering the projected growth rates expected in Bell
County (from 237,974 in 2000, to 397,741 in 2040, a 67 percent increase
over the 40-year period; Texas State Data Center 2009, p. 19), these
Salado salamander spring sites are still at threat from the detrimental
effects of urbanization. The threat of development and urbanization
continues into the foreseeable future because there are no long-term,
binding conservation plans in place for these properties or adequate
regulations in place for the watersheds or recharge zone.
The City of Austin is implementing an HCP to avoid, minimize, and
mitigate incidental take of the Barton Springs salamander resulting
from the continued operation and maintenance of Barton Springs Pool and
adjacent springs (City of Austin 1998, pp. 1-53). Many of the
provisions of the plan also benefit the Austin blind salamander. These
provisions include: (1) Training lifeguard and maintenance staff to
protect salamander habitat, (2) controlling erosion and preventing
surface runoff from entering the springs, (3) ecological enhancement
and restoration, (4) monthly monitoring of salamander numbers, (5)
public outreach and education, and (6) establishment and maintenance of
a captive breeding program, which includes the Austin blind salamander.
As part of this HCP, the City of Austin completed habitat restoration
of Eliza Spring and the main pool of Barton Springs in 2003 and 2004. A
more natural flow regime was reconstructed in these habitats by
removing large obstructions to flow.
Conclusion of Factor A
Degradation of habitat, in the form of reduced water quality and
quantity and disturbance of spring sites (surface habitat), is the
primary threat to the Austin blind, Jollyville Plateau, Georgetown, and
Salado salamanders. Reductions in water quality occur primarily as a
result of urbanization, which increases the amount of impervious cover
in the watershed. Impervious cover increases storm flow velocities and
increases erosion and sedimentation. Impervious cover also changes
natural flow regimes within watersheds and increases the transport of
contaminants common in urban environments, such as oils, metals, and
pesticides.
After identifying 15 watersheds within the Watershed Boundary
Dataset as being occupied by 1 of the 4 central Texas salamander
species, and using the most recent National Land Cover Dataset
impervious cover data available (from 2006), we could draw some
generalizations about how each watershed might be affected by
development. The watershed where the Austin blind salamander is known
to occur has an average overall impervious cover estimate of 12
percent, but also includes some Balcones Canyonlands Preserve lands.
Although this managed open space likely contributes some water quality
benefits to surface flow, the habitat of this largely subterranean
species can be influenced by land use throughout the recharge zone of
the aquifer that supplies its spring flow.
The watersheds within the Jollyville Plateau salamander's range
have average impervious cover estimates that range from approximately 6
percent to 34 percent. Although the Balcones
[[Page 50791]]
Canyonlands Preserve and other lands managed for open space within
these watersheds likely provide some water quality benefits for this
species, five out of the six watersheds that occur within its range
have overall impervious cover estimates that can lead to sharp declines
in water quality or cause permanent conditions of poor water quality
(Schueler 1994, pp. 100-102).
The watersheds within the Georgetown salamander's range have
average impervious cover estimates that range from approximately 0.59
percent to 10 percent. Five out of the six watersheds within this
species' range are well below impervious cover levels that can lead to
declines in water quality. With only two large tracts of land managed
specifically as open space (64 ac (26 ha) and 145 ac (59 ha)) within
the Georgetown salamander's range, it is likely that water quality for
this species' habitat will decline into the future as impervious cover
increases with development.
The two watersheds within the Salado salamander's range have
average impervious cover estimates of 0.31 percent and 0.91 percent.
Although four known Salado salamander sites are located on large,
undeveloped ranches (8,126 ac (3,288 ha) and 827 ac (335 ha)), a
significant portion of the recharge zone for the Northern Segment of
the Edwards Aquifer that supplies water to this species' habitat
extends to areas outside of these properties. Furthermore, we could not
identify any large tracts managed specifically as open space within the
Salado salamander's range. We also could identify no agreements in
place to preserve or manage any properties for the benefit of this
species or its habitat. Without these, it is likely that water quality
within the Salado salamander's habitat will decrease as development and
impervious cover increases in these watersheds in the future.
Expanding urbanization results in an increase of contaminants, such
as fertilizers and pesticides, within the watershed, which degrades
water quality at salamander spring sites. Additionally, urbanization
increases nutrient loads at spring sites, which can lead to decreases
in dissolved oxygen levels. Construction activities are a threat to
both water quality and quantity because they can increase sedimentation
and dewater springs by intercepting aquifer conduits.
Various other threats exist for these species, as well. Drought,
which may be compounded by the effects of global climate change, also
degrades water quality and reduces available habitat for the
salamanders. Water quantity can also be reduced by groundwater pumping.
Flood events contribute to the salamanders' risks of extinction by
degrading water quality through increased sedimentation and
contaminants levels, which may damage or alter substrates. Impoundments
are also a threat for all four central Texas salamanders. Feral hogs
are a threat to Georgetown, Salado, and Jollyville Plateau salamanders
because they can physically alter their surface habitat. Likewise,
livestock are a threat to Georgetown and Salado salamanders' surface
habitat. Additionally, catastrophic spills and leaks remain a threat
for many salamander locations. All of these threats are predicted to
increase in the future, as the human population and development
increases within watersheds that provide habitat for these salamanders.
Overall, we consider the combined threats of Factor A to be ongoing and
with a high degree of impact to all four central Texas salamanders and
their habitats.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
There is no available information regarding overutilization of any
of the four salamander species for commercial, recreational,
scientific, or educational purposes. We do not consider overutilization
to be a threat to the four central Texas salamander species now or in
the future.
Factor C. Disease or Predation
Chytridiomycosis (chytrid fungus) is a fungal disease that is
responsible for killing amphibians worldwide (Daszak et al. 2000, p.
445). The chytrid fungus has been documented on the feet of Jollyville
Plateau salamanders from 15 different sites and on Austin blind
salamanders in the wild (O'Donnell et al. 2006, pp. 22-23; Chamberlain
2011, City of Austin, pers. comm.). However, the salamanders are not
displaying signs of infection (O'Donnell et al. 2006, p. 23). We have
no data to indicate whether impacts from this disease may increase or
decrease in the future, and therefore, whether this disease is a
significant factor affecting the species (a threat). Therefore, we do
not consider chytridiomycosis to be a threat to any of the four central
Texas salamanders at this time.
However, a condition affecting Barton Springs salamanders may also
be a threat to the Austin blind salamander. In 2002, 19 Barton Springs
salamanders, which co-occur with the Austin blind salamander, were
found at Barton Springs with bubbles of gas occurring throughout their
bodies (Chamberlain and O'Donnell 2003, p. 17). Three similarly
affected Barton Springs salamanders also were found in 2003
(Chamberlain, unpublished data). Of the 19 salamanders affected in
2002, 12 were found dead or died shortly after they were found. Both
adult and juvenile Barton Springs salamanders have been affected
(Chamberlain and O'Donnell 2003, pp. 10, 17).
The incidence of gas bubbles in salamanders at Barton Springs is
consistent with a disorder known as gas bubble disease, or gas bubble
trauma, as described by Weitkamp and Katz (1980, pp. 664-671). In
animals with gas bubble trauma, bubbles below the surface of the body
and inside the cardiovascular system produce lesions and dead tissue
that can lead to secondary infections (Weitkamp and Katz 1980, p. 670).
Death from gas bubble trauma is apparently related to an accumulation
of internal bubbles in the cardiovascular system (Weitkamp and Katz
1980, p. 668). Pathology reports on affected animals at Barton Springs
found that the symptoms were consistent with gas bubble trauma
(Chamberlain 2011, pers. comm.). The cause of gas bubble trauma is
unknown, but its incidence has been correlated with water temperature.
Gas bubble trauma has been observed in Austin blind salamanders in
captivity when exposed to water temperatures approaching 80 [deg]F
(26.7 [deg]C) (Chamberlain 2011, pers. comm.).
We consider gas bubble trauma to be a threat with a limited impact
to the Austin blind salamander now and in the future. To our knowledge,
gas bubble trauma has not been observed in Jollyville Plateau,
Georgetown, or Salado salamanders. However, if an increase in water
temperature is a causative factor, these three species may also be at
risk during droughts or other environmental stressors that result in
increases in water temperature. However, at this time, we do not
consider gas bubble trauma to be a threat to the Jollyville Plateau,
Georgetown, or Salado salamanders.
Regarding predation, City of Austin biologists found Jollyville
Plateau salamander abundances were negatively correlated with the
abundance of predatory centrarchid fish (carnivorous freshwater fish
belonging to the sunfish family), such as black bass (Micropterus spp.)
and sunfish (Lepomis spp.) (COA 2001, p. 102). Predation of a
Jollyville Plateau salamander by a centrarchid fish was observed during
a May 2006 field survey (O'Donnell et al. 2006, p. 38). However, Bowles
et al. (2006, pp. 117-118) rarely observed these predators in
Jollyville Plateau salamander habitat.
[[Page 50792]]
Centrarchid fish are currently present in two of three Austin blind
salamander sites (Laurie Dries, City of Austin, unpublished data), and
crayfish (another predator) occupy much of the same habitat as
Georgetown, Salado, and Jollyville Plateau salamanders. All four
salamanders have been observed retreating into gravel substrate after
cover was moved, suggesting these salamanders display anti-predation
behavior (Bowles et al. 2006, p. 117). However, we do not have enough
data to indicate whether predation of the four salamander species may
increase in the future or is a significant factor affecting the species
and therefore a threat. Therefore, we do not consider predation to be a
threat to any of the four central Texas salamanders at this time.
In summary, while predation and disease may be affecting
individuals of these salamander species, we believe that these are not
significant factors affecting the species' continued existence. Neither
predation nor disease is occurring at a level that we consider to be a
threat to the continued existence of any of the four central Texas
salamander species now or in the future.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
Water Quantity and Quality Protections
The main threats to the Austin blind, Jollyville Plateau,
Georgetown, and Salado salamanders are from habitat degradation,
specifically a lowering of water quality and quantity. Therefore,
regulatory mechanisms that protect water from the Edwards Aquifer are
crucial to the future survival of the species. These four salamander
species are not listed on the Texas State List of Endangered or
Threatened Species (TPWD 2011b, pp. 2-3). Therefore, these species are
receiving no direct protection from the State.
Under authority of the Texas Administrative Code (Title 30, Chapter
213), the Texas Commission on Environmental Quality (TCEQ) regulates
activities having the potential for polluting the Edwards Aquifer and
hydrologically connected surface streams. Among other State statutes
designed to protect water quality, the Edwards Rules require a number
of water quality protection measures for new development occurring in
the recharge and contributing zones of the Edwards Aquifer. These
regulations provide incentives to developers in the form of exemptions
and exceptions from permanent water quality control mechanisms for
developments with less than 20 percent impervious cover. However, only
the Georgetown salamander sites and about half of the known Jollyville
Plateau salamander locations occur within those portions of the Edwards
Aquifer regulated by TCEQ. Furthermore, the jurisdiction of the Edwards
Rules does not extend into Bell County or the Barton Springs Segment
(TCEQ 2001, p. 1). Therefore, many salamander populations do not
directly benefit from these protections.
We recognize that implementation of the Edwards Rules in other
areas of the Northern Segment of the Edwards Aquifer may have the
potential to affect conditions at spring sites occupied by the Salado
salamander. For those salamander locations that are covered by the TCEQ
regulations, the regulations do not address land use, impervious cover
limitations, non-point source pollution, or application of fertilizers
and pesticides over the recharge zone (30 TAC 213.3). We are unaware of
any water quality ordinances more restrictive than TCEQ's Edwards Rules
in Bell, Williamson, or Travis Counties outside the City of Austin.
The City of Austin's water quality ordinances (City of Austin Code,
Title 25, Chapter 8) provide some water quality regulatory protection
to the Austin blind and Jollyville Plateau salamanders' habitat within
Travis County. The ordinances range from relatively strict controls in
its extraterritorial jurisdiction to lesser controls in outlying areas.
Some of the protections provided in these ordinances include riparian
buffers, permanent water quality control structures, wastewater system
restrictions, and impervious cover limitations (Turner 2007, pp. 1-2).
Some studies have demonstrated that these ordinances play a role in
protecting Austin-area surface waters from urbanization-related
contaminants. For example, in the period after the City of Austin
passed water quality ordinances in 1986 and 1991, sedimentation and
nutrients decreased in the five major Austin-area creeks (Turner 2007,
p. 7). Peak storm flows were also lower after the enactment of the
ordinances, which may explain the decrease in sedimentation (Turner
2007, p. 10). Likewise, a separate study on the water quality of Walnut
Creek (Jollyville Plateau salamander habitat) from 1996 to 2008 found
that water quality has either remained the same or improved (Scoggins
2010, p. 15). These trends in water quality occurred despite a drastic
increase in construction and impervious cover during the same time
period (Turner 2007, pp. 7-8; Scoggins 2010, p. 4), indicating that the
ordinances are effective at mitigating some of the impacts of
development on water quality. Another study in the Austin area compared
18 sites with stormwater controls (retention ponds) in their watersheds
to 20 sites without stormwater controls (Maxted and Scoggins 2004, p.
8). In sites with more than 40 percent impervious cover, more
contaminant-sensitive macroinvertebrate species were found at sites
with stormwater controls than at sites without controls (Maxted and
Scoggins 2004, p. 11).
However, based on long-term monitoring that shows an overall water
quality decline at Jollyville Plateau and Austin blind salamander
sites, these local ordinances are not effective at reducing contaminant
levels to the extent that they no longer threaten salamander habitat
(see discussion under Factor A). Furthermore, it is unclear how much
surface water quality controls in developed areas benefit groundwater
quality. A City of Austin study of four Jollyville Plateau salamander
spring sites within two subdivisions found that stricter water quality
controls (wet ponds instead of standard sedimentation/filtration ponds)
did not translate into improved groundwater quality (Herrington et al.
2007, pp. 13-14).
In addition, Title 7, Chapter 245 of the Texas Local Government
Code permits ``grandfathering'' of certain local regulations.
Grandfathering allows developments to be exempted from new requirements
for water quality controls and impervious cover limits if the
developments were planned prior to the implementation of such
regulations. However, these developments are still obligated to comply
with regulations that were applicable at the time when project
applications for development were first filed (Title 7, Chapter 245 of
the Texas Local Government Code p. 1). Unpublished data provided by the
City of Austin (2007) indicates that up to 26 percent of undeveloped
areas within watersheds draining to Jollyville Plateau salamander
habitat may be exempted from current water quality control requirements
due to ``grandfathering'' legislation.
On January 1, 2006, the City of Austin banned the use of coal tar
sealant (Scoggins et al. 2009, p. 4909), which has been shown to be the
main source of PAHs in Austin-area streams (Mahler et al. 2005, p.
5565). However, historically applied coal tar sealant lasts for several
years and can remain a source of PAHs to aquatic systems (DeMott et al.
2010, p. 372). A study that examined PAH concentrations in Austin
streams before the ban and 2 years after the ban found no difference,
indicating
[[Page 50793]]
that either more time is needed to see the impact of the coal tar ban,
or that other sources (e.g. airborne and automotive) are contributing
more to PAH loadings (DeMott et al. 2010, pp. 375-377). Furthermore,
coal tar sealant is still legal outside of the City of Austin's
jurisdiction and may be contributing PAH loads to northern Jollyville
Plateau, Georgetown, and Salado salamander habitat.
The TCEQ has required wastewater treatment systems within the
Barton Springs Edwards Aquifer recharge and contributing zones to
obtain a Texas Land Application Permit (TLAP) in order to discharge
effluent onto the land (Ross 2011, p. 7). Although these permits are
designed to protect the surface waters and underground aquifer, studies
have demonstrated reduced water quality downstream of TLAP sites (Ross
2011, pp. 11-18). Ross (2011, pp. 18-21) attributes this regulatory
inadequacy to TCEQ's failure to conduct regular soil monitoring for
nutrient accumulation on TLAP sites, and the failure to conduct indepth
reviews of TLAP applications.
The TCEQ has developed voluntary water quality protection measures
for developers to minimize water quality effects to springs systems and
other aquatic habitats within the Edwards Aquifer region of Texas (TCEQ
2005, p. i). In February 2005, the Service concurred that these
measures, if implemented, would protect several aquatic species from
take, including the Georgetown salamander, due to water quality
degradation resulting from development in the Edwards Aquifer region
(TCEQ 2007, p. 1). However, it should be noted that as non-listed
species, ``take'' prohibitions do not apply. Thus, these water quality
protection measures are not a regulatory mechanism.
The Barton Springs Edwards Aquifer Conservation District permits
and regulates most wells on the Barton Springs segment of the Edwards
Aquifer, subject to the limits of the State law. Bell County's
groundwater resources are currently managed by the Clearwater
Underground Water Conservation District. There are no groundwater
conservation districts in Williamson or northern Travis Counties, so
groundwater pumping is unregulated in these areas (TPWD 2011a, p. 7).
Conclusion of Factor D
Data indicate that water quality degradation in sites occupied by
Austin blind and Jollyville Plateau salamanders continues to occur
despite the existence of current regulatory mechanisms in place to
protect water quality (Turner 2005a, pp. 8-17, O'Donnell et al. 2006,
p. 29). Long-term water quality data are not available for Georgetown
and Salado salamander sites, but rapid human population growth and
urbanization in Williamson and Bell Counties continues. Existing
regulations in these counties do not address many of the sources of
groundwater pollution that are typically associated with urbanized
areas. Therefore, we consider the inadequacy of existing regulatory
mechanisms to be an ongoing, significant threat to all four salamander
species now and in the foreseeable future.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Ultraviolet Radiation
Increased levels of ultraviolet-B (UV-B) radiation, due to
depletion of the stratospheric ozone layers, may lead to declines in
amphibian populations (Blaustein and Kiesecker 2002, pp. 598-600). For
example, research has demonstrated that UV-B radiation causes
significant mortality and deformities in developing long-toed
salamanders (Ambystoma macrodactylum) (Blaustein et al. 1997, p.
13,735). Exposure to UV-B radiation reduces growth in clawed frogs
(Xenopus laevis) (Hatch and Burton, 1998, p. 1,783) and lowers hatching
success in Cascades frogs (Rana cascadae) and western toads (Bufo
boreas) (Kiesecker and Blaustein 1995, pp. 11,050-11,051). In lab
experiments with spotted salamanders, UV-B radiation diminished their
swimming ability (Bommarito et al. 2010, p. 1151). Additionally, UV-B
radiation may act synergistically (the total effect is greater than the
sum of the individual effects) with other factors (for example,
contaminants, pH, pathogens) to cause declines in amphibians (Alford
and Richards 1999, p. 141; see Synergistic and Additive Interactions
among Stressors). Some researchers believe that future increases in UV-
B radiation will have significant detrimental impacts on amphibians
that are sensitive to this radiation (Blaustein and Belden 2003, p.
95).
The effect of increased UV-B radiation on the Austin blind,
Jollyville Plateau, Georgetown, and Salado salamanders is unknown.
These species may be protected from UV-B radiation through shading from
trees at some spring sites. Removal of natural riparian vegetation may
put these species at risk. Because eggs are believed to be deposited
underground (Bendik 2011b, pers. comm.), UV-B radiation may have no
impact on the hatching success of these species. In conclusion, the
effect of increased UV-B radiation has the potential to cause
deformities or developmental problems to individuals, but we do not
consider this stressor to significantly contribute to the risk of
extinction of any of the four central Texas salamander species at this
time.
Deformities in Jollyville Plateau Salamanders
Jollyville Plateau salamanders observed at the Stillhouse Hollow
monitoring sites have shown high incidences of deformities, such as
curved spines, missing eyes, missing limbs or digits, and eye injuries
(O'Donnell et al. 2006, p. 26). The Stillhouse Hollow location was also
cited as having the highest observation of dead Jollyville Plateau
salamanders (COA 2001, p. 88). Although water quality is relatively low
in the Stillhouse Hollow drainage (O'Donnell et al. 2006, pp. 26, 37),
no statistical correlations were found between the number of
deformities and nitrate concentrations (O'Donnell et al. 2006, p. 26).
Environmental toxins are the suspected cause of salamander deformities
(O'Donnell et al. 2006, p. 25; COA 2001, pp. 70-74), but deformities in
amphibians can also be the result of genetic mutations, parasitic
infections, UV-B radiation, or the lack of an essential nutrient. More
research is needed to elucidate the cause of these deformities. We
consider deformities to be a stressor of low level impact to the
Jollyville Plateau salamander because this stressor is only an issue at
one site and it does not appear to be an issue for the other salamander
species.
Small Population Size and Stochastic Events
All four central Texas salamanders may be more susceptible to
threats and impacts from stochastic events because of their small
population sizes. The risk of extinction for any species is known to be
highly indirectly correlated with population size (Ogrady et al. 2004,
pp. 516, 518; Pimm et al. 1988, pp. 774-775). In other words, the
smaller the population, the greater the overall risk of extinction.
True population size estimates have not been generated at most sites
for these species, but mark-recapture studies at some of the highest
quality sites for Georgetown and Jollyville Plateau salamanders
estimated populations as low as 78 (O'Donnell et al. 2008, pp. 44-45).
Populations are likely smaller at lower quality sites. Small population
sizes can also act synergistically with other traits (such as being a
habitat specialist and having
[[Page 50794]]
limited distribution, as is the case with the four salamander species)
to greatly increase risk of extinction (Davies et al. 2004, p. 270).
Stochastic events from either environmental factors (random events such
as severe weather) or demographic factors (random causes of births and
deaths of individuals) may also heighten other threats to the
salamanders because of the limited range and small population sizes
(Melbourne and Hastings 2008, p. 100).
The highly restricted ranges of the salamanders and entirely
aquatic environment make them extremely vulnerable to threats such as
decreases in water quality and quantity. This is especially true for
the Austin blind salamander, which is found in only one locality
comprised of three hydrologically connected springs of Barton Springs,
and the Salado salamander, which has only been found at seven spring
sites. Due to their very limited distribution, the Austin blind and
Salado salamanders are especially sensitive to incidences such as storm
events, which can dramatically affect dissolved oxygen levels and
increase contaminants, and cause catastrophic spills and leaks. One
catastrophic spill event in Barton Springs could potentially cause the
extinction of the Austin blind salamander in the wild.
The presence of several populations of Jollyville Plateau and
Georgetown salamanders does provide some possibility for natural
recolonization for these species if any of these factors resulted in a
local extirpation event (Fagan et al. 2002, p. 3,255). In conclusion,
we do not consider small population size to be a threat in and of
itself to any of the four salamander species, but their small
population sizes may make them more vulnerable to extinction from other
existing or potential threats, such as a major stochastic event.
Therefore, the magnitude of a stochastic event affecting the continued
existence of the Jollyville Plateau and Georgetown salamanders is
moderate because these species have more populations over a broader
range. On the other hand, recolonization following a stochastic event
is less likely for Austin blind and Salado salamanders due to a fewer
number of known sites. Therefore, the impacts from a stochastic event
for the Austin blind and Salado salamanders is a significant threat.
Synergistic and Additive Interactions Among Stressors
The interactions among multiple stressors (for example,
contaminants, UV-B radiation, pathogens) may be contributing to
amphibian population declines (Blaustein and Kiesecker 2002, p. 598).
Multiple stressors may act additively or synergistically to have
greater detrimental impacts on amphibians compared to a single stressor
alone. Kiesecker and Blaustein (1995, p. 11,051) found a synergistic
effect between UV-B radiation and a pathogen in Cascades frogs and
western toads. Researchers demonstrated that reduced pH levels and
increased levels of UV-B radiation independently had no effect on
leopard frog (Rana pipiens) larvae; however, when combined, these two
caused significant mortality (Long et al. 1995, p. 1,302).
Additionally, researchers demonstrated that UV-B radiation increases
the toxicity of PAHs, which can cause mortality and deformities on
developing amphibians (Hatch and Burton 199, pp. 1,780-1,783). Beattie
et al. (1992, p. 566) demonstrated that aluminum becomes toxic to
amphibians at low pH levels. Also, disease outbreaks may occur only
when there are contaminants or other stressors in the environment that
reduce immunity (Alford and Richards 1999, p. 141). For example,
Christin et al. (2003, pp. 1,129-1,130, 1,132) demonstrated that
mixtures of pesticides reduced the immunity to parasitic infections in
leopard frogs.
The effect of synergistic effects between stressors on the Austin
blind, Jollyville Plateau, Georgetown, and Salado salamanders is not
currently known. Furthermore, different species of amphibians differ in
their reactions to stressors and combinations of stressors (Kiesecker
and Blaustein 1995, p. 11,051; Relyea et al. 2009, pp. 367-368; Rohr et
al. 2003, pp. 2,387-2,390). Studies that examine the effects of
interactions among multiple stressors on the four central Texas
salamanders are lacking. However, based on the number of examples in
other amphibians, the possibility of synergistic effects on the four
central Texas salamanders cannot be discounted.
Summary of Factor E
The effect of increased UV-B radiation is an unstudied stressor to
the four central Texas salamanders that has the potential to cause
deformities or development problems. The effect of this stressor is
believed to be low at this time.
Deformities have been documented in one of the four salamander
species (Jollyville Plateau salamander), and at only one location
(Stillhouse Hollow). We do not know what causes these deformities, and
there is no evidence that the incidence rate is increasing or
spreading. Therefore, the effect of this stressor is believed to be
low.
Small population sizes at most of the sites for the salamanders is
not a threat in and of itself, but it may increase the risk of local
extirpation events. However, the Georgetown and Jollyville Plateau
salamanders may have some ability to recolonize sites because they
occur in more populations over a broader range. Thus, we consider the
level of impacts from a stochastic event to be moderate for these two
species and high for the Austin blind and Salado salamanders due to
their more limited distributions.
Finally, the significance of each threat discussed above (under
Factors A through E) may be influenced by their interactions with other
threats, and may subsequently increase under certain conditions.
Overall Threat Summary
The following table provides a general overview of the type,
anticipated level of impact, and timing of threats facing the four
salamanders proposed for listing. It is intended to assist the public
in comparing the threats discussed above among the salamander species.
The magnitude of threat is defined in terms of scope (the relative
proportion or range of the species that is affected by the threat) and
severity (impacts on the overall species' status), such that a high
magnitude of threat indicates that the species is facing the greatest
threats to their continued existence (48 FR 43098; September 21, 1983).
We define imminence as the timing of when a threat begins. A threat is
considered imminent if it is impacting the species now rather than in
the foreseeable future. Some of the threats outlined within Tables 3
through 6 are difficult to fully quantify due to lack of available
information. These threats were designated an unknown magnitude.
Table 3--Summary of Threats to the Austin Blind Salamander
----------------------------------------------------------------------------------------------------------------
Level of impact (low,
Factor Type of threat medium, high) Ongoing?
----------------------------------------------------------------------------------------------------------------
A................................... Contaminants from stormwater High................... Yes.
runoff.
[[Page 50795]]
Sedimentation from High................... Yes.
stormwater runoff.
Changes in flow regime from Med.................... Yes.
impervious cover.
Excess nutrient input....... Low.................... Yes.
Pesticides.................. Low.................... Yes.
Catastrophic hazardous High................... Yes.
material spills.
Pollution from construction Med.................... Yes.
activities.
Construction of pipelines... Low.................... No.
Groundwater pumping......... Med.................... Yes.
Impoundments................ High................... Yes.
Physical modification of Med.................... Yes.
surface habitat for human-
related activities.
Drought..................... Low.................... Yes.
Flooding.................... Low.................... Yes.
Climate change.............. Unknown................ Yes.
C................................... Gas bubble trauma........... Low.................... No.
D................................... Inadequacy of existing High................... Yes.
regulatory mechanisms.
E................................... Small population size and High................... Yes.
stochastic events.
Synergistic and additive Unknown................ Unknown.
interactions among
stressors.
UV-B radiation.............. Unknown................ Unknown.
----------------------------------------------------------------------------------------------------------------
Table 4--Summary of Threats to the Jollyville Plateau Salamander
----------------------------------------------------------------------------------------------------------------
Level of impact (low,
Factor Type of threat medium, high) Ongoing?
----------------------------------------------------------------------------------------------------------------
A................................... Contaminants from stormwater High................... Yes.
runoff.
Sedimentation from High................... Yes.
stormwater runoff.
Changes in flow regime from Med.................... Yes.
impervious cover.
Excess nutrient input....... MedLow................. Yes.
Pesticides.................. Low.................... Yes.
Catastrophic hazardous Low.................... Yes.
material spills.
Pollution from construction HighMed................ Yes.
activities.
Construction of pipelines... Low.................... No.
Construction of the Low.................... Yes.
Jollyville Transmission
Main.
Rock quarries............... Low.................... Yes.
Groundwater pumping......... Med.................... Yes.
Impoundments................ Low.................... Yes.
Feral hogs.................. Low.................... Yes.
Physical modification of Low.................... Yes.
surface habitat for human-
related activities.
Drought..................... MedLow................. Yes.
Flooding.................... Low.................... Yes.
Climate change.............. Unknown................ Yes.
D................................... Inadequacy of existing High................... Yes.
regulatory mechanisms.
E................................... Small population size and Med.................... Yes.
stochastic events.
Synergistic and additive Unknown................ Unknown.
interactions among
stressors.
UV-B radiation.............. Unknown................ Unknown.
----------------------------------------------------------------------------------------------------------------
Table 5--Summary of Threats to the Georgetown Salamander
----------------------------------------------------------------------------------------------------------------
Level of impact (low,
Factor Type of threat medium, high) Ongoing?
----------------------------------------------------------------------------------------------------------------
A................................... Contaminants from stormwater High................... Yes.
runoff.
Sedimentation from High................... Yes.
stormwater runoff.
Changes in flow regime from Med.................... Yes.
impervious cover.
Excess nutrient input....... Low.................... Yes.
Pesticides.................. Low.................... Yes.
Catastrophic hazardous Med.................... Yes.
material spills.
Pollution from construction Med.................... Yes.
activities.
Construction of pipelines... Low.................... No.
Rock quarries............... Low.................... Yes.
Groundwater pumping......... Med.................... Yes.
Impoundments................ Low.................... Yes.
Feral hogs.................. Low.................... Yes.
Livestock................... Low.................... Yes.
Physical modification of Low.................... Yes.
surface habitat for human-
related activities.
Drought..................... MedLow................. Yes.
Flooding.................... Low.................... Yes.
Climate change.............. Unknown................ Yes.
D................................... Inadequacy of existing High................... Yes.
regulatory mechanisms.
[[Page 50796]]
E................................... Small population size and Med.................... Yes.
stochastic events.
Synergistic and additive Unknown................ Unknown.
interactions among
stressors.
UV-B radiation.............. Unknown................ Unknown.
----------------------------------------------------------------------------------------------------------------
Table 6--Summary of Threats to the Salado Salamander
----------------------------------------------------------------------------------------------------------------
Level of impact (low,
Factor Type of threat medium, high) Ongoing?
----------------------------------------------------------------------------------------------------------------
A................................... Contaminants from stormwater Med.................... Yes.
runoff.
Sedimentation from Med.................... Yes.
stormwater runoff.
Changes in flow regime from Low.................... Yes.
impervious cover.
Excess nutrient input....... Low.................... Yes.
Pesticides.................. Low.................... Yes.
Catastrophic hazardous High................... Yes.
material spills.
Pollution from construction Low.................... Yes.
activities.
Construction of pipelines... Low.................... No.
Rock quarries............... Low.................... Yes.
Groundwater pumping......... Med.................... Yes.
Impoundments................ Low.................... Yes.
Feral hogs.................. Low.................... Yes.
Livestock................... Low.................... Yes.
Physical modification of Low.................... Yes.
surface habitat for human-
related activities.
Drought..................... Low.................... Yes.
Flooding.................... Low.................... Yes.
Climate change.............. Unknown................ Yes.
D................................... Inadequacy of existing High................... Yes.
regulatory mechanisms.
E................................... Small population size and High................... Yes.
stochastic events.
Synergistic and additive High................... Yes.
interactions among
stressors.
UV-B radiation.............. Unknown................ Unknown.
----------------------------------------------------------------------------------------------------------------
Proposed Listing Determination
As previously noted, the magnitude of a threat is defined in terms
of scope (the relative proportion or range of the species that is
affected by the threat) and severity (impacts on the overall species'
status), such that a high magnitude of threat indicates that the
species is facing the greatest threats to their continued existence (48
FR 43098; September 21, 1983). We define imminence as the timing of
when a threat begins. A threat is considered imminent if it is
impacting the species now rather than in the foreseeable future.
Austin Blind Salamander
The primary threat to this species is habitat modification (Factor
A) in the form of reduced flows and degradation of water quality of
spring habitats as a result of urbanization within the watersheds and
recharge and contributing zones of the Edwards Aquifer. Substantial
human population growth (a projected increase of 84 percent from 2000
to 2040) is ongoing within Travis County, Texas (Texas State Data
Center 2008, p. 1), the only location where the Austin blind salamander
is known to occur. This human population growth is likely to result in
considerable urbanization within the watershed, which would influence
spring flow and water quality within the salamander's three known sites
at Barton Springs. Urbanization leads to increases in sedimentation,
contaminants, and nutrient loads as well as decreases in aquatic
invertebrates (the salamander's prey base). Significant changes in
water quality constituents have been reported from analyses conducted
from within the Austin blind salamander's habitat at Barton Springs
Pool (COA 1997, pp. 229, 231-232; Mahler and Van Metre 2000, p. 1);
these changes have been attributed to urbanization within the recharge
and contributing zones of the Edwards Aquifer (Turner 2005a, p. 6).
We analyzed the impervious cover estimates of the watershed within
the Austin blind salamander's range, along with the amount of land
currently managed as open space that could possibly contribute water
quality benefits to the salamander's habitats. The watershed where the
Austin blind salamander is known to occur has an average overall
impervious cover estimate of 11.58 percent, which is within the range
in which sharp declines of water quality in aquatic habitats have been
observed (Schueler 1994, pp. 100-102). Although this watershed has some
managed open space that likely contributes water quality benefits to
surface flow, the habitat of this largely subterranean species can be
influenced by land use throughout the recharge zone of the aquifer that
supplies its spring flow. In consideration of this information and
analysis, we believe the threat of habitat modification in the form of
reduced water quality is ongoing and has a high level of impact
throughout the Austin blind salamander's range.
Data indicate that water quality degradation in sites occupied by
Austin blind salamanders continues to occur despite the existence of
current regulatory mechanisms in place designed to protect water
quality (Turner 2005a, pp. 8-17, O'Donnell et al. 2006, p. 29).
Therefore, we consider the inadequacy of existing regulatory mechanisms
to protect against water quality degradation (Factor D) to be a
significant threat.
The Edwards Aquifer is at risk from a variety of sources of
pollutants (Ross 2011, p. 4), including hazardous materials that could
be spilled or leaked, potentially resulting in the contamination of
both surface and groundwater resources (Service 2005, pp. 1.6-14-1.6-
15). A catastrophic spill
[[Page 50797]]
could occur if a truck transporting hazardous materials overturned and
spilled its contents over the recharge zone of the aquifer. The Austin
blind salamander is at considerable risk from hazardous materials
spills given that it only occurs at three spring sites in one locality
(Barton Springs). Among other sources, there is the potential for a
catastrophic gasoline spill in the Barton Springs Segment of the
Edwards Aquifer from the Longhorn pipeline (EPA 2000, pp. 9-29-9-30).
There is also potential for hazardous material spills from the multiple
drinking water lines and sewage pipelines surrounding Barton Springs.
For these reasons, we believe the threat of habitat modification in the
form of water quality degradation and contamination from hazardous
materials spills to be an ongoing threat of high impact to this
species.
Construction activities resulting from urban development are a
threat to both water quality and quantity because they can increase
sedimentation and dewater springs by intercepting aquifer conduits.
Austin blind salamander habitat at Barton Springs is under the threat
of pollutant loading due to its proximity to construction activities
and its location at the downstream side of the watershed (COA 1997, p.
237). Given that construction-related sediment loading is already
occurring within the Austin blind salamander's narrowly restricted
range, we believe the threat of habitat modification in the form of
water quality degradation and changes to water flows caused by
construction activities from urban development to be an ongoing threat
of medium impact to this species.
Another potential threat to the Austin blind salamander and its
habitat is low flow conditions in the aquifer and at Barton Springs.
Groundwater pumping can cause such conditions and lead to saline water
encroachments in the aquifer. Water quality in the Barton Springs
Segment of the Edwards Aquifer has been degraded in the past due to
saline encroachment (Slade et al. 1986, p. 62). This water quality
degradation occurred when Barton Springs discharge was less than 30 cfs
(Slade et al. 1986, p. 64). Reduced groundwater levels could also
increase the concentration of some pollutants in the aquifer. Average
flows at Barton Springs have dropped below 17 cfs as recently as mid-
November 2011 (Barton Springs/Edwards Aquifer Conservation District
2011, p. 1). This saline water encroachment would threaten the
freshwater biota in the springs and the aquifer, including the Austin
blind salamander, by dramatically changing the water chemistry (such as
increasing conductivity).
In addition to groundwater pumping, low flows in Barton Springs may
be attributed to ongoing urbanization and recent drought conditions.
Future climate change could also affect water quantity and spring flow
for the Austin blind salamander. Climate change could compound the
threat of decreased water quantity at salamander spring sites. The
effects of climate change on aquifer-dependant species is difficult to
assess; however, the Edwards Aquifer is predicted to experience
additional stress from climate change that could lead to decreased
recharge and low or ceased spring flows given increasing pumping
demands (Lo[aacute]iciga et al. 2000, pp. 192-193). In any case, we
believe habitat modification in the form of water quantity reduction,
whether reduced spring flows are caused by climate change or are in
combination with other stressors, to be an ongoing threat of high
impact to this species.
The Austin blind salamander is sensitive to direct physical habitat
modification, such as modification resulting from human recreational
activities and impoundments. Eliza Spring and Sunken Garden Spring, two
of the three locations of the Austin blind salamander, also experience
vandalism, despite the presence of fencing and signage (Dries 2011,
pers. comm.). The deep water of Barton Springs likely protects the
Austin blind salamander's surface habitat from damage from frequent
human recreation.
All spring sites for the Austin blind salamander (Main, Eliza, and
Sunken Garden springs) have been impounded for recreational use. While
the manmade structures help retain water in the spring pools during low
flows, they have altered the salamander's natural environment. The
impoundments have changed the Barton Springs ecosystem from a stream-
like system to a more lentic (still water) environment, thereby
reducing the water system's ability to flush sediments downstream and
out of salamander habitat. Because of the physical habitat
modifications that have permanently impacted the Austin blind
salamander's habitat or are currently ongoing, we consider this threat
to be ongoing and of high impact to this species.
Gas bubble trauma has been observed in Austin blind salamanders in
captivity (Chamberlain 2011, pers. comm.), and has been known to affect
another salamander species (the Barton Springs salamander) at Barton
Springs (Chamberlain 2011, pers. comm.). Chytrid fungus has also been
documented on the feet of Austin blind salamanders in the wild
(O'Donnell et al. 2006, pp. 22-23). However, we have no data to
indicate whether disease or predation (Factor C) of any of the
salamander species proposed for listing is a significant threat facing
the species. Predation and disease may be affecting these salamander
species, but there is not enough evidence to consider these factors
threats. Neither factor is at a level that we consider to be
threatening the continued existence of the salamander species now or in
the foreseeable future.
Other natural or manmade factors (Factor E) affecting the Austin
blind salamander include UV-B radiation, small population sizes,
stochastic events, and synergistic and additive interactions among
stressors. Increased levels of UV-B radiation, due to the depletion of
stratospheric ozone layers has been shown to cause significant
mortality and deformities in amphibian species (Blaustein et al. 1997,
p. 13,735), although the effects of UV-B radiation on this species are
unknown. Small population sizes may act synergistically with other
traits of the species (such as its limited distribution) to increase
its overall risk of extinction (Davies et al. 2004, p. 270). Stochastic
events, such as severe weather or demographic changes to the
population, are also heightened threats because of its restricted range
and small population sizes (Melbourne and Hastings 2008, p. 100). We
therefore consider this to be an ongoing threat of high impact.
The population status of Austin blind salamanders is unknown,
largely because it is rarely seen at the water's surface (Hillis et al.
2001, p. 267). However, observations of Austin blind salamanders have
been decreasing in recent years (2009-2010) (COA 2011a, pp. 51-52).
From January 1998 to December 2000, there were only 17 documented
observations of the Austin blind salamander (Hillis et al. 2001, p.
273). The abundance of Austin blind salamanders increased slightly from
2002 to 2006, but fewer observations have been made in more recent
years (2009 to 2010) (COA 2011a, pp. 51-52). Because fewer observations
coincide with habitat degradation throughout the species' entire range,
we expect the downward trend to continue into the future as human
population growth and urbanization drive further declines in habitat
quality and quantity. Due to its small range and probable small
population size, we believe the species resiliency to the threats
outlined above is low.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a
[[Page 50798]]
significant portion of its range'' and a threatened species as any
species ``that is likely to become endangered throughout all or a
significant portion of its range within the foreseeable future.'' Due
to small population size, limited range, and susceptibility to ongoing
threats, we determine that the Austin blind salamander is currently on
the brink of extinction and therefore meets the definition of
endangered. We find that the Austin blind salamander is presently in
danger of extinction throughout its entire range based on the
immediacy, severity, and scope of the threats described above. The
Austin blind salamander species is proposed as endangered, rather than
threatened, because the threats are occurring now, and their impacts to
the species and its habitat would be catastrophic given the very
limited range of the species, making the salamander at risk of
extinction at the present time. Therefore, on the basis of the best
available scientific and commercial information, we propose listing the
Austin blind salamander as endangered in accordance with sections 3(6)
and 4(a)(1) of the Act.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. The Austin blind salamander proposed
for listing in this rule is highly restricted in its range, and the
threats occur throughout its entire range. Therefore, the threats to
the survival of this species are not restricted to any particular
significant portion of that range. Accordingly, our assessment and
proposed determination applies to the species throughout its entire
range.
Jollyville Plateau Salamander
The primary threat to this species is habitat modification (Factor
A) in the form of reduced flows and degradation of water quality of
spring habitats as a result of human population growth and subsequent
urbanization within the watersheds and recharge and contributing zones
of the Edwards Aquifer. Substantial human population growth is ongoing
within this species' range. The Texas State Data Center (2008, p. 1)
has reported a population increase of 84 percent and 597 percent for
Travis and Williamson Counties, Texas, respectively. This population
growth is likely to result in considerable urbanization within the
watersheds that contribute to spring flow and thereby influence water
quality within the salamander's habitat. Urbanization leads to
increases in water demand and reduced water quality from erosion,
sedimentation, contaminants, and nutrient loads as well as decreases in
aquatic invertebrates (the salamanders' prey base). Specifically,
elevated PAH and conductivity levels as well as excessive sedimentation
have been documented within Jollyville Plateau salamander habitat and
have been associated with population declines observed during
monitoring (COA 2001, pp. 101, 126; O'Donnell et al. 2006, pp. 37, 47).
Poor water quality, particularly elevated nitrates, is also believed to
be a cause of morphological deformities observed in individual
Jollyville Plateau salamanders (O'Donnell et al. 2006, pp. 26, 37).
We analyzed the impervious cover estimates of each watershed within
the Jollyville Plateau salamander's range, along with the amount of
land currently managed as open space that could possible contribute
water quality benefits to the salamander's habitats. The watersheds
within the Jollyville Plateau salamander's range have average
impervious cover estimates that range from 5.72 percent to 34.32
percent. Although the Balcones Canyonlands Preserve and other lands
managed for open space within these watersheds likely provide some
water quality benefits for this species, five out of the six watersheds
that occur within its range have overall impervious cover estimates
that can lead to sharp declines in water quality or cause permanent
conditions of poor water quality (Schueler 1994, pp. 100-102). In
consideration of this information and analysis, we believe the threat
of habitat modification in the form of reduced water quality is ongoing
and of high impact throughout the Jollyville Plateau salamander's
range.
Data indicate that water quality degradation in sites occupied by
Jollyville Plateau salamanders continues to occur despite the existence
of current regulatory mechanisms in place to protect water quality
(Turner 2005a, pp. 8-17, O'Donnell et al. 2006, p. 29); therefore,
these mechanisms are not adequate to protect this species and its
habitat. Therefore, we consider the inadequacy of existing regulatory
mechanisms (Factor D) to be an ongoing threat of high impact.
The Edwards Aquifer is at risk from a variety of sources of
pollutants (Ross 2011, p. 4), including hazardous materials that could
be spilled or leaked, potentially resulting in the contamination of
both surface and groundwater resources (Service 2005, pp. 1.6-14-1.6-
15). A catastrophic spill could occur if a truck transporting hazardous
materials overturned and spilled its contents over the recharge zone of
the aquifer. The transport of hazardous materials is common on many
highways that serve as major transportation routes (Service 2005, p.
1.6-13).
A number of point-sources of pollutants exist within the Jollyville
Plateau salamander's range, including leaking underground storage tanks
and sewage spills from pipelines (COA 2001, pp. 16, 21, 74). A
significant hazardous materials spill within a stream drainage for the
Jollyville Plateau salamander could have the potential to threaten the
long-term survival and sustainability of multiple populations. Because
of these reasons, we believe the threat of habitat modification in the
form of water quality degradation and contamination from hazardous
materials spills to be an ongoing threat of low impact to this species.
Construction activities resulting from urban development are a
threat to both water quality and quantity because they can increase
sedimentation and dewater springs by intercepting aquifer conduits.
Increased sedimentation from construction activities has been linked to
declines in Jollyville Plateau salamander counts at multiple sites
(Turner 2003, p. 24; O'Donnell et al. 2006, p. 34). Given that
construction-related sediment loading is likely to occur from ongoing
urbanization within the Jollyville Plateau salamander's range, we
believe the threat of habitat modification in the form of water quality
degradation and water reduction caused by construction activities from
urban development to be an ongoing threat of high impact to this
species.
Another potential threat to the Jollyville Plateau salamander and
its habitat is low flow conditions in the aquifer and within this
species' surface habitat due to urbanization and recent drought
conditions. The City of Austin found a negative correlation between
urbanization and spring flows at Jollyville Plateau salamander sites
(Turner 2003, p. 11). Field studies have also shown that a number of
springs that support Jollyville Plateau salamanders have already gone
dry periodically, and that spring waters resurface following rain
events (O'Donnell et al. 2006, pp. 46-47).
Future climate change could also affect water quantity and spring
flow for the Jollyville Plateau salamander. Climate change could
compound the threat of decreased water quantity at salamander spring
sites. The effects of climate change on aquifer-dependant species is
difficult to assess; however, the Edwards Aquifer is predicted to
experience additional stress from climate change that could lead to
decreased recharge and low or ceased
[[Page 50799]]
spring flows given increasing pumping demands (Lo[aacute]iciga et al.
2000, pp. 192-193). Therefore, we believe habitat modification in the
form of water quantity reduction, whether reduced spring flows is
caused by climate change or in combination with other stressors, to be
an ongoing threat of unknown impact to this species.
All four salamanders are sensitive to direct physical habitat
modification, such as those resulting from human recreational
activities, impoundments, feral hogs, and livestock. Destruction of
Jollyville Plateau salamander habitat has been attributed to vandalism
(COA 2001, p. 21), human recreational use (COA 2001, p. 21),
impoundments (O'Donnell et al. 2008, p.1; Bendik 2011b, pers. comm.),
and feral hog activity (O'Donnell et al. 2006, pp. 34, 46). Because
there is ongoing physical habitat modification occurring to known
Jollyville Plateau salamander sites, we consider this threat to be
ongoing and of low impact to this species.
Chytrid fungus has also been documented on the feet of Jollyville
Plateau salamanders in the wild, but with no visible symptoms of the
disease (O'Donnell et al. 2006, pp. 22-23). Furthermore, there are no
data to indicate whether disease or predation of any of the salamander
species proposed for listing is a significant threat facing these
species. Predation and disease (Factor C) may be affecting the
Jollyville Plateau salamander species, but there is not enough evidence
to consider these factors threats. Neither factor is at a level that we
consider to be threatening the continued existence of the Jollyville
Plateau salamander now or in the foreseeable future.
Other natural or manmade factors (Factor E) affecting the
Jollyville Plateau salamander include UV-B radiation, small population
sizes, stochastic events, and synergistic and additive interactions
among stressors. Increased levels of UV-B radiation, due to the
depletion of stratospheric ozone layers has been shown to cause
significant mortality and deformities that affect reproduction in
amphibian species (Blaustein et al. 1997, p. 13,735), although the
effects of UV-B radiation on this species are unknown. Small population
sizes may act synergistically with other traits of the species (such as
its limited distribution) to increase its overall risk of extinction
(Davies et al. 2004, p. 270). Stochastic events, such as severe weather
or demographic changes to the population, are also heightened threats
because of the species' restricted range and small population sizes
(Melbourne and Hastings 2008, p. 100). We therefore consider this to be
an ongoing threat of medium impact.
The population status of Jollyville Plateau salamanders is unknown
at most of their sites. However, observations of Jollyville Plateau
salamanders at several long-term monitoring sites have been decreasing
in correspondence with habitat degradation (O'Donnell et al. 2006, pp.
4, 48). We expect the downward trend to continue into the future as
human population growth and urbanization drive further declines in
habitat quality and quantity.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as any species ``that is likely to
become endangered throughout all or a significant portion of its range
within the foreseeable future.'' Due to its susceptibility to threats
that are ongoing throughout its entire range, we determine that the
Jollyville Plateau salamander is currently on the brink of extinction
and therefore meets the definition of endangered. We find that the
Jollyville Plateau salamander is presently in danger of extinction
throughout its entire range based on the immediacy, severity, and scope
of the threats described above. The Jollyville Plateau salamander
species is proposed as endangered, rather than threatened, because the
threats are occurring now or are imminent, and their potential impacts
to the species would be catastrophic given the very limited range of
the species, making the salamander at risk of extinction at the present
time. Therefore, on the basis of the best available scientific and
commercial information, we propose listing the Jollyville Plateau
salamander as endangered in accordance with sections 3(6) and 4(a)(1)
of the Act.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. The Jollyville Plateau salamander
proposed for listing in this rule is highly restricted in its range,
and the threats occur throughout its entire range. Therefore, the
threats to the survival of this species are not restricted to any
particular significant portion of that range. Accordingly, our
assessment and proposed determination applies to the species throughout
its entire range.
Georgetown Salamander
The primary threat to this species is habitat modification (Factor
A) in the form of reduced flows and degradation of water quality of
spring habitats as a result of urbanization within the watersheds and
recharge and contributing zones of the Edwards Aquifer. Williamson
County, Texas, is experiencing tremendous human population growth. An
increase of 597 percent from 2000 to 2040 is currently projected (Texas
State Data Center 2008, p.1). Along with human population growth, we
expect more urbanization, which leads to increases in sedimentation,
contaminants, and nutrient loads as well as decreases in aquatic
invertebrates (the salamanders' prey base).
We analyzed the impervious cover estimates of each watershed within
the Georgetown salamander's range, along with the amount of land
currently managed as open space that could possibly contribute water
quality benefits to the salamander's habitat. The watersheds within the
Georgetown salamander's range have average impervious cover estimates
that range from 0.59 percent to 9.60 percent. Five out of the six
watersheds within this species' range are well below impervious cover
levels that can lead to declines in water quality.
Although our analyses indicated relatively low levels of impervious
cover throughout the watersheds within the Georgetown salamander's
range, there are developed areas that could be affecting the water
quality at sites known to be occupied by the Georgetown salamander.
Moreover, existing regulations in Williamson County do not address many
of the sources of groundwater pollution that are typically associated
with urbanized areas; therefore, these regulations are not adequate to
protect this species and its habitat. With only two large tracts (64 ac
[25.9 ha] and 145 ac [58.7 ha]) protected as open space within the
Georgetown salamander's range, it is unlikely the water quality for
this species' habitat will be protected as development continues into
the foreseeable future. In consideration of this information and
analysis, we believe the threat of habitat modification in the form of
reduced water quality is ongoing and of high impact throughout the
Georgetown salamander's range.
In regards to regulatory mechanisms to protect water quality, it is
unlikely that water quality within the Georgetown salamander's habitat
will be maintained or protected as urbanization occurs in these
watersheds into the foreseeable future. Therefore, we consider the
inadequacy of existing regulatory mechanisms (Factor D) to be an
ongoing threat of high impact.
The Edwards Aquifer is at risk from a variety of sources of
pollutants (Ross
[[Page 50800]]
2011, p. 4), including hazardous materials that could be spilled or
leaked, potentially resulting in the contamination of both surface and
groundwater resources (Service 2005, pp. 1.6-14-1.6-15). A catastrophic
spill could occur if a truck transporting hazardous materials
overturned and spilled its contents over the recharge zone of the
aquifer. Interstate Highway 35 crosses watersheds that contribute
groundwater to spring sites known to be occupied by the Georgetown
salamander.
The Georgetown salamander is also at risk from several other point
sources of pollutants, including wastewater pipelines, chlorinated
drinking water lines, and septic systems. A significant hazardous
materials spill within a stream drainage for the Georgetown salamander
could have the potential to threaten the long-term survival and
sustainability of multiple populations. For these reasons, we believe
the threat of habitat modification in the form of water quality
degradation and contamination from hazardous materials spills to be an
ongoing threat of medium impact to this species.
Construction activities resulting from urban development are a
threat to both water quality and quantity because they can increase
sedimentation and dewater springs by intercepting aquifer conduits.
There are currently three active rock quarries located near Georgetown
salamander sites within Williamson County, Texas, which may impact the
species and its habitat, which could result in the destruction of
spring sites, collapse of karst caverns, degradation of water quality,
and reduction of water quantity (Ekmekci 1990, p. 4). Given that
construction-related sediment loading is likely to occur within the
rapidly developing range of the Georgetown salamander, we believe the
threat of habitat modification in the form of water quality degradation
and water reduction caused by construction activities from urban
development to be an ongoing threat of medium impact to this species.
Another potential threat to the Georgetown salamander and its
habitat is low flow conditions in the aquifer and within this species'
surface habitat due to urbanization and recent drought conditions. The
San Gabriel Springs (Georgetown salamander habitat) are now only
intermittently flowing in the summer due to pumping from nearby water
wells (TPWD 2011a, p. 9). Salamanders have not been seen on the surface
there since 1991 (Chippindale et al. 2000, p. 40; Pierce 2011b, pers.
comm.). Although Eurycea salamanders may spend some time below the
surface in underground aquatic habitat areas to adapt to periodic flow
losses (O'Donnell et al. 2006, p. 47), drying spring habitats can
result in stranding salamanders (TPWD 2011a, p. 5). Also, prey
availability is likely low underground due to the lack of primary
production (Hobbs and Culver 2009, p. 392).
Future climate change could also affect water quantity and spring
flow for the Georgetown salamander. Climate change could compound the
threat of decreased water quantity at salamander spring sites. The
effects of climate change on aquifer-dependant species is difficult to
assess; however, the Edwards Aquifer is predicted to experience
additional stress from climate change that could lead to decreased
recharge and low or ceased spring flows given increasing pumping
demands (Lo[aacute]iciga et al. 2000, pp. 192-193). In consideration of
the information presented above, we believe habitat modification in the
form of water quantity reduction to be an ongoing threat of high impact
to this species.
All four salamanders are sensitive to direct physical habitat
modification, such as those resulting from human recreational
activities, impoundments, feral hogs, and livestock. Destruction of
Georgetown salamander habitat has been attributed to direct human
modification (TPWD 2011a, p. 9), feral hog activity (O'Donnell et al.
2006, pp. 34, 46; Booker 2011, p. 1), and livestock activity (White
2011, SWCA, pers. comm.). Because there is ongoing physical habitat
modification occurring to known Georgetown salamander sites within a
restricted range, we consider this to be an ongoing threat of low
impact for this species.
Predation and disease (Factor C) may be affecting the Georgetown
salamander, but there is not enough evidence to consider these factors
threats . Neither factor is at a level that we consider to be
threatening the continued existence of the Georgetown salamander
species now or in the foreseeable future.
Other natural or manmade factors (Factor E) potentially affecting
the Georgetown salamander include UV-B radiation, small population
sizes, stochastic events, and synergistic and additive interactions
among stressors. Increased levels of UV-B radiation, due to the
depletion of stratospheric ozone layers has been shown to cause
significant mortality and deformities in amphibian species (Blaustein
et al. 1997, p. 13,735), although the effects of UV-B radiation on this
species are unknown. Small population sizes may act synergistically
with other traits of the species (such as its limited distribution) to
increase its overall risk of extinction (Davies et al. 2004, p. 270).
Stochastic events, such as severe weather or demographic changes to the
population, are also heightened threats because of its restricted range
and small population sizes (Melbourne and Hastings 2008, p. 100). We
therefore consider this to be an ongoing threat of medium impact.
The population status of Georgetown salamanders is unknown at all
but two of their sites. A lack of long-term data prevents us from
drawing conclusions on how Georgetown salamander populations may be
changing over time. However, similar to Austin blind and Jollyville
plateau salamander populations, we expect Georgetown salamander
populations to trend downwards in the future as human population growth
and urbanization in the area drive declines in habitat quality and
quantity.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as any species ``that is likely to
become endangered throughout all or a significant portion of its range
within the foreseeable future.'' Due to its susceptibility to threats
that are ongoing throughout its entire range, we determine that the
Georgetown salamander is currently on the brink of extinction and
therefore meets the definition of endangered. We find that the
Georgetown salamander is presently in danger of extinction throughout
its entire range based on the immediacy, severity, and scope of the
threats described above. The Georgetown salamander species is proposed
as endangered, rather than threatened, because the threats are
occurring now or are imminent, and their potential impacts to the
species would be catastrophic given the very limited range of the
species, making the salamander at risk of extinction at the present
time. Therefore, on the basis of the best available scientific and
commercial information, we propose listing the Georgetown salamander as
endangered in accordance with sections 3(6) and 4(a)(1) of the Act.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. The Georgetown salamander proposed
for listing in this rule is highly restricted in its range, and the
threats occur throughout its entire range. Therefore, the threats to
the survival of this species are not restricted to any particular
significant portion of that range. Accordingly, our assessment and
[[Page 50801]]
proposed determination applies to the species throughout its entire
range.
Salado Salamander
The primary threat to this species is habitat modification (Factor
A) in the form of reduced flows and degradation of water quality of
spring habitats as a result of urbanization within the watersheds and
recharge and contributing zones of the Edwards Aquifer. Urbanization
leads to increases in sedimentation, contaminants, and nutrient loads
as well as decreases in aquatic invertebrates (the Salado salamander's
prey base).
We analyzed the impervious cover estimates of each watershed within
the Salado salamander's range along with the amount of land currently
managed as open space that could possibly contribute water quality
benefits to the salamander's habitat. The two watersheds within the
Salado salamander's range have 0.31 percent and 0.91 percent impervious
cover. Although four known Salado salamander sites are located on
large, undeveloped ranches (8,126 ac [3,288 ha] and 827 ac [335 ha]), a
significant portion of the recharge zone for the Northern Segment of
the Edwards Aquifer that supplies water to this species' habitat
extends to areas outside of these properties. We could not identify any
large tracts managed specifically as open space within the Salado
salamander's range. We also could not identify any agreements in place
to preserve or manage any properties for the benefit of this species or
its habitat. Furthermore, population projections from the Texas State
Data Center (2009, p. 19) estimate that Bell County will increase in
population from 237,974 in 2000, to 397,741 in 2040, a 67 percent
increase over the 40-year period. In consideration of this information
and analysis, we believe the threat of habitat modification in the form
of water quality degradation is ongoing and of medium impact throughout
the Salado salamander's range.
In regards to adequate regulatory mechanisms to protect water
quality, it is unlikely that water quality within the Salado
salamander's habitat will be protected if development occurs in these
watersheds into the foreseeable future. We therefore consider the
inadequacy of existing regulatory mechanisms (Factor D) to be an
ongoing threat of high impact.
The Edwards Aquifer is at risk from a variety of sources of
pollutants (Ross 2011, p. 4), including hazardous materials that could
be spilled or leaked, potentially resulting in the contamination of
both surface and groundwater resources (Service 2005, pp. 1.6-14-1.6-
15). A catastrophic spill could occur if a truck transporting hazardous
materials overturned and spilled its contents over the recharge zone of
the aquifer. Salado salamander sites located downstream of Interstate
Highway 35 may be particularly vulnerable due to their proximity to
this major transportation corridor. Should a hazardous materials spill
occur at the Interstate Highway 35 bridge that crosses at Salado Creek,
this species could be at risk from contaminants entering the water
flowing into its surface habitat downstream.
Several groundwater contamination incidents have occurred within
Salado salamander habitat (Price et al. 1999, p. 10). Because these
groundwater contamination events are already occurring and because the
Salado salamander's range is restricted to only a few known spring
sites, we consider the threat of hazardous materials spills to be
ongoing and of high impact to this species.
Construction activities resulting from urban development are a
threat to both water quality and quantity because they can increase
sedimentation and dewater springs by intercepting aquifer conduits. The
Service is not aware of any specific, large-scale construction
activities currently ongoing within the Salado salamander's range.
However, because the human population is increasing rapidly in this
area, urbanization and subsequent construction activities are likely to
impact the few known Salado salamander populations within the
foreseeable future. Thus, we believe construction activities are an
ongoing threat of low impact to this species.
Another potential threat to the Salado salamander and its habitat
is low flow conditions in the aquifer and within this species' surface
habitat due to urbanization and recent drought conditions. Robertson
Springs (Salado salamander habitat) reportedly went temporarily dry in
2009 (TPWD 2011a, p. 5). Although Eurycea salamanders may spend some
time below the surface in underground aquatic habitat areas to adapt to
periodic flow losses (O'Donnell et al. 2006, p. 47), drying spring
habitats can result in stranding salamanders (TPWD 2011a, p. 5). Also,
prey availability is likely low underground due to the lack of primary
production (Hobbs and Culver 2009, p. 392).
Future climate change could also affect water quantity and spring
flow for the Salado salamander. Climate change could compound the
threat of decreased water quantity at salamander spring sites. The
effects of climate change on aquifer-dependant species is difficult to
assess; however, the Edwards Aquifer is predicted to experience
additional stress from climate change that could lead to decreased
recharge and low or ceased spring flows given increasing pumping
demands (Lo[aacute]iciga et al. 2000, pp. 192-193). In consideration of
the information presented above, we believe that habitat modification
in the form of water quantity reduction to be an ongoing threat of
medium magnitude to this species.
All four salamanders are sensitive to direct physical habitat
modification, such as those resulting from human recreational
activities, impoundments, feral hogs, and livestock. Destruction of
Salado salamander habitat has been attributed to direct human
modification (including heavy machinery use, outflow channel
reconstruction, and substrate alteration at Big Boiling Springs) and
feral hog activity (Service 2010b, p. 6; Gluesenkamp 2011a, b, pers.
comm.). Because there is ongoing physical habitat modification
occurring to known Salado salamander sites within a very restricted
range, we consider this threat resulting from human recreational
activities to be ongoing and of low impact to this species.
Furthermore, we consider the threats of impoundments, feral hogs, and
livestock to be ongoing, but of low impact.
Predation and disease (Factor C) may be affecting the Salado
salamander, but there is not enough evidence to consider these factors
threats. Neither factor is at a level that we consider to be
threatening the continued existence of the Salado salamander species
now or in the foreseeable future.
Other natural or manmade factors (Factor E) affecting the Salado
salamander include UV-B radiation, small population sizes, stochastic
events, and synergistic and additive interactions among stressors.
Increased levels of UV-B radiation, due to the depletion of
stratospheric ozone layers has been shown to cause significant
mortality and deformities in amphibian species (Blaustein et al. 1997,
p. 13,735), although the effects of UV-B radiation on this species are
unknown. Small population sizes may act synergistically with other
traits of the species (such as its limited distribution) to increase
its overall risk of extinction (Davies et al. 2004, p. 270). Stochastic
events, such as severe weather or demographic changes to the
population, are also heightened threats because of its restricted range
and small population sizes (Melbourne and Hastings 2008, p. 100). We
therefore consider this to be an ongoing threat of high impact.
[[Page 50802]]
The population status of Salado salamanders is unknown. A lack of
long-term data prevents us from drawing conclusions on how Salado
salamander populations may be changing over time. However, similar to
Austin blind and Jollyville plateau salamander populations, we expect
Salado salamander populations to trend downwards in the future as human
population growth and urbanization in the area drive declines in
habitat quality and quantity. Due to its relatively small range and
small number of populations, we believe the species' resiliency to the
threats outlined above is low.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as any species ``that is likely to
become endangered throughout all or a significant portion of its range
within the foreseeable future.'' Due to its susceptibility to threats
that are ongoing throughout its entire range, we determine that the
Salado salamander is currently on the brink of extinction and therefore
meets the definition of endangered. We find that the Salado salamander
is presently in danger of extinction throughout its entire range, based
on the immediacy, severity, and scope of the threats described above.
This salamander species is proposed as endangered, rather than
threatened, because the threats are occurring now or are imminent, and
their potential impacts to the species would be catastrophic given the
very limited range of the species, making the salamander at risk of
extinction at the present time. Therefore, on the basis of the best
available scientific and commercial information, we propose listing the
Salado salamander as endangered in accordance with sections 3(6) and
4(a)(1) of the Act.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. The Salado salamander proposed for
listing in this rule is highly restricted in its range, and the threats
occur throughout its entire range. Therefore, the threats to the
survival of this species are not restricted to any particular
significant portion of that range. Accordingly, our assessment and
proposed determination applies to the species throughout its entire
range.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing can result in public awareness
and conservation by Federal, State, Tribal, and local agencies, private
organizations, and individuals. The Act encourages cooperation with the
States and requires that recovery actions be carried out for all listed
species. The protection required by Federal agencies and the
prohibitions against certain activities are discussed, in part, below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Subsection 4(f) of the Act requires the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning includes the development of a recovery outline
shortly after a species is listed, preparation of a draft and final
recovery plan, and revisions to the plan as significant new information
becomes available. The recovery outline guides the immediate
implementation of urgent recovery actions and describes the process to
be used to develop a recovery plan. The recovery plan identifies site-
specific management actions that will achieve recovery of the species,
measurable criteria that determine when a species may be downlisted or
delisted, and methods for monitoring recovery progress. Recovery plans
also establish a framework for agencies to coordinate their recovery
efforts and provide estimates of the cost of implementing recovery
tasks. Recovery teams (comprised of species experts, Federal and State
agencies, non-government organizations, and stakeholders) are often
established to develop recovery plans. If we list these four central
Texas salamanders, when completed, the recovery outline, draft recovery
plan, and the final recovery plan will be available on our Web site
(http://www.fws.gov/endangered), or from our Austin Ecological Services
Field Office (see FOR FURTHER INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, Tribal, non-governmental organizations, businesses,
and private landowners. Examples of recovery actions include habitat
restoration (for example, restoration of native vegetation), research,
captive propagation and reintroduction, and outreach and education. The
recovery of many listed species cannot be accomplished solely on
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these four species requires
cooperative conservation efforts on private, local government, and
other lands.
If these species are listed, funding for recovery actions will be
available from a variety of sources, including Federal budgets, State
programs, and cost share grants for non-Federal landowners, the
academic community, and non-governmental organizations. In addition,
pursuant to section 6 of the Act, the State of Texas would be eligible
for Federal funds to implement management actions that promote the
protection and recovery of the Austin blind, Jollyville Plateau,
Georgetown, and Salado salamanders. Information on our grant programs
that are available to aid species recovery can be found at: http://www.fws.gov/grants.
Although the Austin blind, Jollyville Plateau, Georgetown, and
Salado salamanders are only proposed for listing under the Act at this
time, please let us know if you are interested in participating in
recovery efforts for this species. Additionally, we invite you to
submit any new information on this species whenever it becomes
available and any information you may have for recovery planning
purposes (see FOR FURTHER INFORMATION CONTACT).
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as
endangered or threatened and with respect to its critical habitat, if
any is designated. Regulations implementing this interagency
cooperation provision of the Act are codified at 50 CFR part 402.
Section 7(a)(4) of the Act requires Federal agencies to confer with the
Service on any action that is likely to jeopardize the continued
existence of a species proposed for listing or result in destruction or
adverse modification of proposed critical habitat. If a species is
listed subsequently, section 7(a)(2) of the Act requires Federal
agencies to ensure that activities they authorize, fund, or carry out
are not likely to jeopardize the continued existence of the species or
destroy or adversely modify its critical habitat. If a Federal
[[Page 50803]]
action may affect a listed species or its critical habitat, the
responsible Federal agency must enter into consultation with the
Service.
Federal agency actions within the species habitat that may require
conference or consultation or both as described in the preceding
paragraph include, but are not limited to, issuance of section 404
Clean Water Act permits by the U.S. Army Corps of Engineers;
construction and management of gas pipeline and power line rights-of-
way by the Federal Energy Regulatory Commission; Federal Emergency
Management Agency for floodplain map revisions; U.S. Department of
Agriculture Rural Development grants; Housing and Urban Development
grants; Service for Partners projects; Service issuance of section 10
permits under the Act; construction and maintenance of roads or
highways by the Federal Highway Administration; Natural Resources
Conservation Service funded projects; and Environmental Protection
Agency pesticide registration.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to all endangered
wildlife. The prohibitions of section 9(a)(2) of the Act, codified at
50 CFR 17.21 for endangered wildlife, in part, make it illegal for any
person subject to the jurisdiction of the United States to take
(includes harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect; or to attempt any of these), import, export, ship
in interstate commerce in the course of commercial activity, or sell or
offer for sale in interstate or foreign commerce any listed species.
Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 3371-3378), it is also
illegal to possess, sell, deliver, carry, transport, or ship any such
wildlife that has been taken illegally. Certain exceptions apply to
agents of the Service and State conservation agencies.
We may issue permits to carry out otherwise prohibited activities
involving endangered and threatened wildlife species under certain
circumstances. Regulations governing permits are codified at 50 CFR
17.22 for endangered species, and at 17.32 for threatened species. With
regard to endangered wildlife, a permit must be issued for the
following purposes: For scientific purposes, to enhance the propagation
or survival of the species, and for incidental take in connection with
otherwise lawful activities.
It is our policy, as published in the Federal Register on July 1,
1994 (59 FR 34272), to identify to the maximum extent practicable at
the time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a proposed
listing on proposed and ongoing activities within the range of the
species proposed for listing. The following activities could
potentially result in a violation of section 9 of the Act; this list is
not comprehensive:
(1) Unauthorized collecting, handling, possessing, selling,
delivering, carrying, or transporting of the species, including import
or export across State lines and international boundaries, except for
properly documented antique specimens of these taxa at least 100 years
old, as defined by section 10(h)(1) of the Act.
(2) Introduction of nonnative species that compete with or prey
upon any of the four salamanders, such as the introduction of
competing, nonnative aquatic animals to the State of Texas.
(3) The unauthorized release of biological control agents that
attack any life stage of these four species.
(4) Unauthorized modification of the spring opening, stream
channel, or water flow of any spring or stream or removal or
destruction of substrate in any body of water in which any of the four
salamanders are known to occur.
(5) The interception of groundwater such that it reduces water flow
into any waters where any of the four salamanders are known to occur.
(6) Unauthorized discharge of chemicals or fill material into any
waters in which any of the four salamanders are known to occur.
If the four central Texas salamanders are listed under the Act, the
State of Texas' endangered species law is automatically invoked, which
would also prohibit take of these species and encourage conservation by
State government agencies. Chapter 68, section 68.002 of the TPWD's
Code defines State-level endangered species as those species of fish or
wildlife indigenous to Texas that are listed on: (1) The United States
List of Endangered and Threatened Wildlife; or (2) the list of fish or
wildlife threatened with Statewide extinction as filed by the director
of the department. Further, the State of Texas may enter into
agreements with Federal agencies to administer and manage any area
required for the conservation, management, enhancement, or protection
of endangered species. Funds for these activities could be made
available under section 6 of the Act (Cooperation with the States).
Thus, the Federal protection afforded to these species by listing them
as endangered species will be reinforced and supplemented by protection
under State law.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Austin
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Requests for copies of the regulations concerning listed animals and
general inquiries regarding prohibitions and permits may be addressed
to the U.S. Fish and Wildlife Service, Endangered Species Permits,
10711 Burnet Road, Suite 200, Austin, TX 78758; telephone 512-490-0057;
facsimile 512-490-0974.
Prudency Determination
Section 4 of the Act, as amended, and implementing regulations (50
CFR 424.12), require that, to the maximum extent prudent and
determinable, the Secretary designate critical habitat at the time the
species is determined to be endangered or threatened. Our regulations
at 50 CFR 424.12(a)(1) state that the designation of critical habitat
is not prudent when one or both of the following situations exist: (1)
The species is threatened by taking or other activity and the
identification of critical habitat can be expected to increase the
degree of threat to the species; or (2) the designation of critical
habitat would not be beneficial to the species.
There is no documentation that the four Texas salamanders are
significantly threatened by collection. Although human visitation to
four Texas salamanders' habitat carries with it the possibility of
introducing infectious disease and potentially increasing other threats
where the salamanders occur, the locations of important recovery areas
are already accessible to the public through Web sites, reports, online
databases, and other easily accessible venues. Therefore, identifying
and mapping critical habitat is unlikely to increase threats to the
four Texas salamander species or their habitats. In the absence of
finding that the designation of critical habitat would increase threats
to a species, if there are any benefits to a critical habitat
designation, then a prudent finding is warranted. The potential
benefits of critical habitat to the four Texas salamanders include: (1)
Triggering consultation under section 7 of the Act where a Federal
nexus may not otherwise occur (for example, a critical habitat unit may
become unoccupied, and without critical habitat designation, a
consultation would not occur on a project that may affect an unoccupied
area); (2) focusing conservation activities on the most essential
features and areas; (3) providing educational
[[Page 50804]]
benefits to State or county governments, or private entities; and (4)
preventing people from causing inadvertent harm to the species.
Therefore, because we have determined that the designation of critical
habitat will not likely increase the degree of threat to any of the
four salamander species and may provide some measure of benefit, we
find that designation of critical habitat is prudent for the Austin
blind, Jollyville Plateau, Georgetown, and Salado salamanders.
Proposed Critical Habitat Designation for the Four Central Texas
Salamanders
Background
It is our intent to discuss below only those topics directly
relevant to the designation of critical habitat for the Austin blind,
Jollyville Plateau, Georgetown, and Salado salamanders in this section
of the proposed rule.
Critical habitat is defined in section 3 of the Act as:
(1) The specific areas within the geographical area occupied by the
species, at the time it is listed in accordance with the Act, on which
are found those physical or biological features
(a) Essential to the conservation of the species and
(b) Which may require special management considerations or
protection; and
(2) Specific areas outside the geographical area occupied by the
species at the time it is listed, upon a determination that such areas
are essential for the conservation of the species.
Conservation, as defined under section 3 of the Act, means to use
and the use of all methods and procedures that are necessary to bring
an endangered or threatened species to the point at which the measures
provided pursuant to the Act are no longer necessary. Such methods and
procedures include, but are not limited to, all activities associated
with scientific resources management such as research, census, law
enforcement, habitat acquisition and maintenance, propagation, live
trapping, and transplantation, and, in the extraordinary case where
population pressures within a given ecosystem cannot be otherwise
relieved, may include regulated taking.
Critical habitat receives protection under section 7 of the Act
through the requirement that Federal agencies ensure, in consultation
with the Service, that any action they authorize, fund, or carry out is
not likely to result in the destruction or adverse modification of
critical habitat. The designation of critical habitat does not affect
land ownership or establish a refuge, wilderness, reserve, preserve, or
other conservation area. Such designation does not allow the government
or public to access private lands. Such designation does not require
implementation of restoration, recovery, or enhancement measures by
non-Federal landowners. Where a landowner requests Federal agency
funding or authorization for an action that may affect a listed species
or critical habitat, the consultation requirements of section 7(a)(2)
of the Act would apply, but even in the event of a destruction or
adverse modification finding, the obligation of the Federal action
agency and the landowner is not to restore or recover the species, but
to implement reasonable and prudent alternatives to avoid destruction
or adverse modification of critical habitat.
Under the first prong of the Act's definition of critical habitat,
areas within the geographical area occupied by the species at the time
it was listed are included in a critical habitat designation if they
contain physical or biological features (1) which are essential to the
conservation of the species and (2) which may require special
management considerations or protection. For these areas, critical
habitat designations identify, to the extent known using the best
scientific data available, those physical or biological features that
are essential to the conservation of the species (such as space, food,
cover, and protected habitat). In identifying those physical or
biological features within an area, we focus on the principal
constituent elements (primary constituent elements such as roost sites,
nesting grounds, seasonal wetlands, water quality, tide, soil type)
that are essential to the conservation of the species. Primary
constituent elements are the elements or components of physical or
biological features that are essential to the conservation of the
species.
Under the second prong of the Act's definition of critical habitat,
we can designate critical habitat in areas outside the geographical
area occupied by the species at the time it is listed, upon a
determination that such areas are essential for the conservation of the
species. For example, an area currently occupied by the species but
that was not occupied at the time of listing may be essential to the
conservation of the species and may be included in the critical habitat
designation. We designate critical habitat in areas outside the
geographical area occupied by a species only when a designation limited
to its range would be inadequate to ensure the conservation of the
species.
Section 4 of the Act requires that we designate critical habitat on
the basis of the best scientific data available. Further, our Policy on
Information Standards Under the Endangered Species Act (published in
the Federal Register on July 1, 1994 (59 FR 34271)), the Information
Quality Act (section 515 of the Treasury and General Government
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)),
and our associated Information Quality Guidelines, provide criteria,
establish procedures, and provide guidance to ensure that our decisions
are based on the best scientific data available. They require our
biologists, to the extent consistent with the Act and with the use of
the best scientific data available, to use primary and original sources
of information as the basis for recommendations to designate critical
habitat.
When we are determining which areas should be designated as
critical habitat, our primary source of information is generally the
information developed during the listing process for the species.
Additional information sources may include the recovery plan for the
species, articles in peer-reviewed journals, conservation plans
developed by States and counties, scientific status surveys and
studies, biological assessments, other unpublished materials, or
experts' opinions or personal knowledge.
Habitat is dynamic, and species may move from one area to another
over time. We recognize that critical habitat designated at a
particular point in time may not include all of the habitat areas that
we may later determine are necessary for the recovery of the species.
For these reasons, a critical habitat designation does not signal that
habitat outside the designated area is unimportant or may not be needed
for recovery of the species. Areas that are important to the
conservation of the species, both inside and outside the critical
habitat designation, will continue to be subject to: (1) Conservation
actions implemented under section 7(a)(1) of the Act, (2) regulatory
protections afforded by the requirement in section 7(a)(2) of the Act
for Federal agencies to ensure their actions are not likely to
jeopardize the continued existence of any endangered or threatened
species, and (3) the prohibitions of section 9 of the Act if actions
occurring in these areas may affect the species. Federally funded or
permitted projects affecting listed species outside their designated
critical habitat areas may still result in jeopardy
[[Page 50805]]
findings in some cases. These protections and conservation tools will
continue to contribute to recovery of this species. Similarly, critical
habitat designations made on the basis of the best available
information at the time of designation will not control the direction
and substance of future recovery plans, habitat conservation plans
(HCPs), or other species conservation planning efforts if new
information available at the time of these planning efforts calls for a
different outcome.
Physical or Biological Features
In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and
regulations at 50 CFR 424.12, in determining which areas within the
geographic area occupied by the species at the time of listing to
designate as critical habitat, we consider the physical or biological
features that are essential to the conservation of the species and
which may require special management considerations or protection.
These include, but are not limited to:
(1) Space for individual and population growth and for normal
behavior;
(2) Food, water, air, light, minerals, or other nutritional or
physiological requirements;
(3) Cover or shelter;
(4) Sites for breeding, reproduction, or rearing (or development)
of offspring; and
(5) Habitats that are protected from disturbance or are
representative of the historical, geographic, and ecological
distributions of a species.
We derive the specific physical or biological features required for
the four central Texas salamander species from studies of these
species' habitat, ecology, and life history as described below.
Additional information can be found in the listing portion of this
proposed rule. We have determined that the aquatic ecosystem of the
Barton Springs Segment of the Edwards Aquifer is the physical or
biological feature essential for the Austin blind salamander. We have
determined that the aquatic ecosystem of the Northern Segment of the
Edwards Aquifer is the physical or biological feature essential for the
Jollyville Plateau salamander, the Georgetown salamander, and the
Salado salamander.
Space for Individual and Population Growth and for Normal Behavior
Austin Blind Salamander
The Austin blind salamander has been found where water emerges from
the ground as a free-flowing spring. However, this species is rarely
seen at the surface of the spring, so it is assumed that it is
subterranean for most of its life (Hillis et al. 2001, p. 267).
Supporting this assumption is the fact that the species' physiology is
cave-adapted, with reduced eyes and pale coloration (Hillis et al.
2001, p. 267). Most individuals found on the surface near spring
openings are juveniles (Hillis et al. 2001, p. 273). Austin blind
salamanders have been found in the streambed a short distance (about 33
ft (10 m)) downstream of Sunken Gardens Spring (Dries, 2011, pers.
comm.). Therefore, based on the information above, we identify springs,
associated streams, and underground spaces within the aquifer to be the
primary components of the physical or biological features essential to
the conservation of this species.
Jollyville Plateau Salamander
The Jollyville Plateau salamander occurs where water emerges from
the ground as a free-flowing spring and stream. Within the spring
ecosystem, proximity to the springhead is important because of the
appropriate stable water chemistry and temperature, substrate, and flow
regime. Jollyville Plateau salamanders are known to use the underground
aquifer for habitat when surface habitats go dry (Bendik 2011a, p. 31).
Georgetown salamanders, a closely related species, are found up to 164
ft (50 m) from a spring opening (Pierce et al. 2011a, p. 4), but they
are most abundant within the first 16 ft (5 m) (Pierce et al. 2010, p.
294). Forms of Jollyville Plateau salamander with cave morphology have
been found in several underground streams (Chippindale et al. 2000, pp.
36-37; TPWD 2011a, pp. 9-10). Therefore, based on the information
above, we identify springs, associated streams, and underground spaces
within the aquifer to be the primary components of the physical or
biological features essential to the conservation of this species.
Georgetown Salamander
The Georgetown salamander occurs where water emerges from the
ground as a free-flowing spring and stream. Within the spring
ecosystem, proximity to the springhead is important because of the
appropriate stable water chemistry and temperature, substrate, and flow
regime. Georgetown salamanders are found within 164 ft (50 m) of a
spring opening (Pierce et al. 2011a, p. 4), but they are most abundant
within the first 16 ft (5 m) (Pierce et al. 2010, p. 294). Georgetown
salamanders are also thought to use the underground aquifer for
habitat, similar to other closely related Eurycea species. Forms of
Georgetown salamander with cave morphology have been found at two
locations (TPWD 2011a, p. 8), indicating that they spend most of their
lives underground at these locations. Therefore, based on the
information above, we identify springs, associated streams, and
underground spaces within the aquifer to be the primary components of
the physical or biological features essential to the conservation of
this species.
Salado Salamander
The Salado salamander occurs where water emerges from the ground as
a free-flowing spring and stream. Within the spring ecosystem,
proximity to the springhead is important because of the appropriate
stable water chemistry and temperature, substrate, and flow regime.
Eurycea salamanders are rarely found more than 66 ft (20 m) from a
spring source (TPWD 2011, p. 3). However, Georgetown salamanders, a
similar species, are found up to 164 ft (50 m) downstream of a spring
opening. Salado salamanders are also thought to use the underground
aquifer for habitat in times of drought when surface habitat is no
longer available or suitable (TPWD 2011, p. 3), similar to other
closely related Eurycea species (Bendik 2011a, p. 31). Therefore, based
on the information above, we identify springs, associated streams, and
underground spaces within the aquifer to be the primary components of
the physical or biological features essential to the conservation of
this species.
Food, Water, Air, Light, Minerals, or Other Nutritional or
Physiological Requirements
Austin Blind Salamander
No species-specific dietary study has been completed, but the diet
of the Austin blind salamander is presumed to be similar to other
Eurycea species, consisting of small aquatic invertebrates such as
amphipods, copepods, isopods, and insect larvae (reviewed in COA 2001,
pp. 5-6). The feces of one wild-caught Austin blind salamander
contained amphipods, ostracods, copepods, and plant material (Hillis et
al. 2001, p. 273).
Austin blind salamanders are strictly aquatic and spend their
entire lives submersed in water from the Barton Springs Segment of the
Edwards Aquifer (Hillis et al. 2001, p. 273). These salamanders, and
the prey that they feed on, require water sourced from the Edwards
Aquifer at sufficient flows (quantity) to meet all of their
physiological requirements. This water
[[Page 50806]]
should be flowing and unchanged in chemistry, temperature, and volume
from natural conditions. The average water temperature at Austin blind
salamander sites in Barton Springs is between 67.8 and 72.3 [deg]F
(19.9 and 22.4 [deg]C) (COA 2011b, unpublished data).
Edwards Aquifer Eurycea are adapted to a lower ideal range of
oxygen saturations compared to other salamanders (Turner 2009, p. 11).
However, Eurycea salamanders need dissolved oxygen concentrations to be
above a certain concentration, as the co-occurring Barton Springs
salamander demonstrates declining abundance with declining dissolved
oxygen levels (Turner 2009, p. 14). Woods et al. (2010, p. 544)
observed a number of physiological effects to low dissolved oxygen
concentrations (below 4.5 milligrams of oxygen per liter (mg
L-1)) in the related San Marcos salamander, including
decreased metabolic rates and decreased juvenile growth rates. Barton
Springs salamander abundance is highest when dissolved oxygen is
between 5 to 7 mg L-1 (Turner 2009, p. 12). Therefore, we
assume that the dissolved oxygen level of water is important to the
Austin blind salamander as well. The mean annual dissolved oxygen (from
2003 through 2011) at Main Spring, Eliza Spring, and Sunken Garden
Spring is 6.36, 5.89, and 5.95 mg L-1, respectively (COA
2011b, unpublished data).
The conductivity of water is also important to salamander
physiology because it is related to the concentration of ions in the
water. Increased conductivity is associated with increased water
contamination and decreased Eurycea abundance (Willson and Dorcas 2003,
pp. 766-768; Bowles et al. 2006, pp. 117-118). The lower limit of
observed conductivity in developed Jollyville Plateau salamander sites
where salamander densities were lower was 800 microsiemens per
centimeter ([mu]S cm-\1\) (Bowles et al. 2006, p. 117).
Salamanders were significantly more abundant at undeveloped sites where
water conductivity averaged 600 [mu]S cm-\1\ (Bowles et al.
2006, p. 117). Because of its similar physiology to the Jollyville
Plateau salamander, we assume that the Austin blind salamander will
have a similar response to elevated water conductance. Although one
laboratory study on the related San Marcos salamander demonstrated that
conductivities up to 2738 [mu]S cm-1 had no measurable
effect on adult activity (Woods and Poteet 2006, p. 5), it remains
unclear how elevated water conductance might affect juveniles or the
long-term health of salamanders in the wild. In the absence of better
information on the sensitivity of salamanders to changes in
conductivity (or other contaminants), it is reasonable to assume that
salamander survival, growth, and reproduction will be most successful
when water quality is unaltered from natural aquifer conditions. The
average water conductance at Main Spring, Eliza Spring, and Sunken
Garden Spring is between 605 and 740 [mu]S cm-\1\,
respectively (COA 2011b, unpublished data).
Therefore, based on the information above, we identify aquatic
invertebrates and water from the Barton Springs Segment of the Edwards
Aquifer with adequate dissolved oxygen concentration, water
conductance, and water temperature to be the essential components of
the physical or biological features essential to the conservation of
this species.
Jollyville Plateau Salamander
As in other Eurycea species, the Jollyville Plateau salamander
feeds on aquatic invertebrates that commonly occur in spring
environments (reviewed in COA 2001, pp. 5-6). A gut content analysis by
the City of Austin demonstrated that this salamander preys on varying
proportions of ostracods, copepods, mayfly larvae, fly larvae, snails,
water mites, aquatic beetles, and stone fly larvae depending on the
location of the site (Bendik 2011b, p. 55).
Jollyville Plateau salamanders are strictly aquatic and spend their
entire lives submersed in water from the Northern Segment of the
Edwards Aquifer (COA 2001, pp. 3-4; Bowles et al. 2006, p. 112). These
salamanders, and the prey that they feed on, require water sourced from
the Edwards Aquifer at sufficient flows (quantity) to meet all of their
physiological requirements. This water should be flowing and unchanged
in chemistry, temperature, and volume from natural conditions. The
average water temperature at Jollyville Plateau salamander sites with
undeveloped watersheds ranges from 65.3 to 67.3 [deg]F (18.5 to 19.6
[deg]C) (Bowles et al. 2006, p. 115).
Edwards Aquifer Eurycea are adapted to a lower ideal range of
oxygen saturations compared to other salamanders (Turner 2009, p. 11).
However, Eurycea salamanders need dissolved oxygen concentrations to be
above a certain concentration, as the related Barton Springs salamander
demonstrates declining abundance with declining dissolved oxygen levels
(Turner 2009, p. 14). In addition, Woods et al. (2010, p. 544) observed
a number of physiological effects to low dissolved oxygen
concentrations (below 4.5 mg L-\1\) in the related San
Marcos salamander, including decreased metabolic rates and decreased
juvenile growth rates. The average dissolved oxygen level of Jollyville
Plateau salamander sites with little or no development in the watershed
ranges from 5.6 to 7.1 mg L-\1\ (Bendik 2011a, p. 10). Based
on this information, we conclude that the dissolved oxygen level of
water is important to the Jollyville Plateau salamander for respiratory
function.
The conductivity of water is also important to salamander
physiology because it is related to the concentration of ions in the
water. Increased conductivity is associated with increased water
contamination and decreased Eurycea abundance (Willson and Dorcas 2003,
pp. 766-768; Bowles et al. 2006, pp. 117-118). The lower limit of
conductivity in developed Jollyville Plateau salamander sites where
salamander densities were lower was 800 [mu]S cm-\1\ (Bowles
et al. 2006, p. 117). Salamanders were significantly more abundant at
undeveloped sites where water conductivity averaged 600 [mu]S
cm-\1\ (Bowles et al. 2006, p. 117). The average water
conductance of Jollyville Plateau salamander sites with little or no
development in the watershed ranges from 550 to 625 [mu]S
cm-\1\ (Bendik 2011a, p. 10, Bowles et al. 2006, p.115).
Although one laboratory study on the related San Marcos salamander
demonstrated that conductivities up to 2738 [mu]S cm-\1\ had
no measurable effect on adult activity (Woods and Poteet 2006, p. 5),
it remains unclear how elevated water conductance might affect
juveniles or the long-term health of salamanders in the wild. In the
absence of better information on the sensitivity of salamanders to
changes in conductivity (or other contaminants), it is reasonable to
assume that salamander survival, growth, and reproduction will be most
successful when water quality is unaltered from natural aquifer
conditions.
Therefore, based on the information above, we identify aquatic
invertebrates and water from the Northern Segment of the Edwards
Aquifer, including adequate dissolved oxygen concentration, water
conductance, and water temperature, to be the essential components of
the physical or biological features essential for the conservation of
this species.
[[Page 50807]]
Georgetown Salamander
No species-specific dietary study has been completed, but the diet
of the Georgetown salamander is presumed to be similar to other Eurycea
species, consisting of small aquatic invertebrates such as amphipods,
copepods, isopods, and insect larvae (reviewed in COA 2001, pp. 5-6).
Georgetown salamanders are strictly aquatic and spend their entire
lives submersed in water from the Northern Segment of the Edwards
Aquifer (Pierce et al. 2010, p. 296). These salamanders, and the prey
that they feed on, require water sourced from the Edwards Aquifer at
sufficient flows (quantity) to meet all of their physiological
requirements (TPWD 2011a, p. 8). This water should be flowing and
unchanged in chemistry, temperature, and volume from natural
conditions. Normal water temperature at a relatively undisturbed
Georgetown salamander site ranges from 68.4 to 69.8 [deg]F (20.2 to
21.0 [deg]C) throughout the year (Pierce et al. 2010, p. 294).
Edwards Aquifer Eurycea are adapted to a lower ideal range of
oxygen saturations compared to other salamanders (Turner 2009, p. 11).
However, Eurycea salamanders need dissolved oxygen concentrations to be
above a certain threshold, as the related Barton Springs salamander
demonstrates declining abundance with declining dissolved oxygen levels
(Turner 2009, p. 14). In addition, Woods et al. (2010, p. 544) observed
a number of physiological effects to low dissolved oxygen
concentrations (below 4.5 mg L-1) in the related San Marcos
salamander, including decreased metabolic rates and decreased juvenile
growth rates. Georgetown salamander sites are characterized by high
levels of dissolved oxygen, typically 6 to 8 mg L-1 (Pierce
and Wall 2011, p. 33). Therefore, we assume that the dissolved oxygen
level of water is important to the Georgetown salamander for
respiratory function.
The conductivity of water is also important to salamander
physiology because it is related to the concentration of ions in the
water. Increased conductivity is associated with increased water
contamination and decreased Eurycea abundance (Willson and Dorcas 2003,
pp. 766-768; Bowles et al. 2006, pp. 117-118). The lower limit of
observed conductivity in developed Jollyville Plateau salamander sites
where salamander densities were lower was 800 [micro]S cm-1
(Bowles et al. 2006, p. 117). Salamanders were significantly more
abundant at undeveloped sites where water conductivity averaged 600
[micro]S cm-1 (Bowles et al. 2006, p. 117). Because of its
similar physiology to the Jollyville Plateau salamander, we assume that
the Georgetown salamander will have a similar response to elevated
water conductance. Normal water conductance at a relatively undisturbed
Georgetown salamander site ranges from 604 to 721 [micro]S
cm-1 throughout the year (Pierce et al. 2010, p. 294).
Although one laboratory study on the related San Marcos salamander
demonstrated that conductivities up to 2738 [micro]S cm-1
had no measurable effect on adult activity (Woods and Poteet 2006, p.
5), it remains unclear how elevated water conductance might affect
juveniles or the long-term health of salamanders in the wild. In the
absence of better information on the sensitivity of salamanders to
changes in conductivity (or other contaminants), it is reasonable to
assume that salamander survival, growth, and reproduction will be most
successful when water quality is unaltered from natural aquifer
conditions.
Therefore, based on the information above, we identify aquatic
invertebrates and water from the Northern Segment of the Edwards
Aquifer, including adequate dissolved oxygen concentration, water
conductance, and water temperature, to be essential components of the
physical or biological features essential for the conservation of this
species.
Salado Salamander
No species-specific dietary study has been completed, but the diet
of the Salado salamander is presumed to be similar to other Eurycea
species, consisting of small aquatic invertebrates such as amphipods,
copepods, isopods, and insect larvae (reviewed in COA 2001, pp. 5-6).
As with other central Texas Eurycea species, Salado salamanders are
strictly aquatic. Individuals spend their entire lives submersed in
water from the Northern Segment of the Edwards Aquifer (TPWD 2011a, p.
3). These salamanders, and the prey that they feed on, require water
sourced from the Edwards Aquifer at sufficient flows (quantity) to meet
all of their physiological requirements. This water should be flowing
and unchanged in chemistry, temperature, and volume from natural
conditions.
Edwards Aquifer Eurycea are adapted to a lower ideal range of
oxygen saturations compared to other salamanders (Turner 2009, p. 11).
However, Eurycea salamanders need dissolved oxygen concentrations to be
above a certain threshold, as the related Barton Springs salamander
demonstrates declining abundance with declining dissolved oxygen levels
(Turner 2009, p. 14). In addition, Woods et al. (2010, p. 544) observed
a number of physiological effects to low dissolved oxygen
concentrations (below 4.5 mg L-1) in the related San Marcos
salamander, including decreased metabolic rates and decreased juvenile
growth rates. Therefore, we assume that the dissolved oxygen level of
water is important to the Salado salamander for respiratory function.
We also assume that the conductivity of water is important to
salamander physiology because it is related to the concentration of
ions in the water. Increased conductivity is associated with increased
water contamination and decreased Eurycea abundance (Willson and Dorcas
2003, pp. 766-768; Bowles et al. 2006, pp. 117-118). The lower limit of
conductivity in developed Jollyville Plateau salamander sites where
salamander densities were lower was 800 [micro]S cm-1
(Bowles et al. 2006, p. 117). Salamanders were significantly more
abundant at undeveloped sites where water conductivity averaged 600
[micro]S cm-1 (Bowles et al. 2006, p. 117). Although one
laboratory study on the related San Marcos salamander demonstrated that
conductivities up to 2738 [micro]S cm-1 had no measurable
effect on adult activity (Woods and Poteet 2006, p. 5), it remains
unclear how elevated water conductance might affect juveniles or the
long-term health of salamanders in the wild. In the absence of better
information on the sensitivity of salamanders to changes in
conductivity (or other contaminants), it is reasonable to assume that
salamander survival, growth, and reproduction will be most successful
when water quality is unaltered from natural aquifer conditions.
Therefore, based on the information above, we identify aquatic
invertebrates and water from the Northern Segment of the Edwards
Aquifer, including adequate dissolved oxygen concentration, water
conductance, and water temperature, to be essential components of the
physical or biological features essential for the conservation of this
species.
Cover or Shelter
Austin Blind Salamander
The Austin blind salamander likely spends most of its life below
the surface in the aquifer, and may only be flushed to the surface
accidentally (Hillis et al. 2001, p. 273). While on the surface near
spring outlets, they move into interstitial spaces (empty voids between
rocks) within the substrate, using these
[[Page 50808]]
spaces for foraging habitat and cover from predators similar to other
Eurycea salamanders in central Texas (Cole 1995, p. 24; Pierce and Wall
2011, pp. 16-17). The surface is believed to be important as a source
of food for this primarily subterranean species. These spaces should be
free from sediment, as sediment fills interstitial spaces, eliminating
resting places and also reducing habitat of the prey base (small
aquatic invertebrates) (O'Donnell et al. 2006, p. 34). Austin blind
salamanders have been observed under rocks and vegetation (Dries 2011,
pers. comm.).
Therefore, based on the information above, we identify rocky
substrate, consisting of boulder, cobble, and gravel, with interstitial
space that is free from sediment, to be an essential component of the
physical or biological features essential for the conservation of this
species.
Jollyville Plateau Salamander
Similar to other Eurycea salamanders in central Texas, Jollyville
Plateau salamanders move an unknown depth into the interstitial spaces
(empty voids between rocks) within the substrate, using these spaces
for foraging habitat and cover from predators (Cole 1995, p. 24; Pierce
and Wall 2011, pp. 16-17). These spaces should be free from sediment,
as sediment fills interstitial spaces, eliminating resting places and
also reducing habitat of the prey base (small aquatic invertebrates)
(O'Donnell et al. 2006, p. 34).
Jollyville Plateau salamanders have been observed under rocks, leaf
litter, and other vegetation (Bowles et al. 2006, pp. 114-116). There
was a strong positive relationship between salamander abundance and the
amount of available rocky substrate (Bowles et al. 2006, p. 114).
Therefore, based on the information above, we identify rocky
substrate, consisting of boulder, cobble, and gravel, with interstitial
space that is free from sediment, to be an essential component of the
physical or biological features essential for the conservation of this
species.
Georgetown Salamander
Similar to other Eurycea salamanders in central Texas, Georgetown
salamanders move an unknown depth into the interstitial spaces (empty
voids between rocks) within the substrate, using these spaces for
foraging habitat and cover from predators (Cole 1995, p. 24; Pierce and
Wall 2011, pp. 16-17). These spaces should be free from sediment, as
sediment fills interstitial spaces, eliminating resting places and also
reducing habitat of the prey base (small aquatic invertebrates)
(O'Donnell et al. 2006, p. 34).
Georgetown salamanders have been observed under rocks, leaf litter,
woody debris, and other cover objects (Pierce et al. 2010, p. 295).
There is evidence that these salamanders prefer large rocks over other
cover objects (Pierce et al. 2010, p. 295), which is consistent with
other studies on Eurycea habitat (Bowles et al. 2006, p. 114).
Therefore, based on the information above, we identify rocky
substrate, consisting of boulder, cobble, and gravel, with interstitial
space that is free from sediment, to be an essential component of the
physical or biological features essential for the conservation of this
species.
Salado Salamander
Because of its similarity to other Eurycea salamanders in central
Texas, we assume that the Salado salamander spends some proportion of
its life below the surface between rocks. Eurycea salamanders move an
unknown depth into the interstitial spaces (empty voids between rocks)
within the substrate, using these spaces for foraging habitat and cover
from predators (Cole 1995, p. 24; Pierce and Wall 2011, pp. 16-17).
These spaces should be free from sediment, as sediment fills
interstitial spaces, eliminating resting places and also reducing
habitat of the prey base (small aquatic invertebrates) (O'Donnell et
al. 2006, p. 34).
Salado salamanders have been observed under cover objects, such as
rocks (Gluesenkamp 2011a, pers. comm.). Although no study has
demonstrated the substrate preference of the Salado salamander, we
assume that this species prefers large rocks over other cover objects,
similar to other closely related Eurycea salamanders. Larger rocks
provide more suitable interstitial spaces for foraging and cover.
Therefore, based on the information above, we identify rocky
substrate, consisting of boulder, cobble, and gravel, with interstitial
space that is free from sediment, to be an essential component of the
physical or biological features essential for the conservation of this
species.
Sites for Breeding, Reproduction, or Rearing (or Development) of
Offspring
Austin Blind Salamander
Little is known about the reproductive habits of this species.
However, the Austin blind salamander is fully aquatic, and therefore
spends all of its life cycles in aquifer and spring waters. Eggs of
central Texas Eurycea are rarely seen on the surface, so it is widely
assumed that eggs are laid underground (Gluesenkamp 2011a, pers. comm.;
Bendik 2011b, pers. comm.). Most Austin blind salamanders found on the
surface are juveniles (Hillis et al. 2001, p. 267).
Jollyville Plateau Salamander
Little is known about the reproductive habits of this species.
However, the Jollyville Plateau salamander is fully aquatic, and
therefore spends all of its life cycles in aquifer and spring waters.
Eggs of central Texas Eurycea are rarely seen on the surface, so it is
widely assumed that eggs are laid underground (Gluesenkamp 2011a, pers.
comm.; Bendik 2011b, pers. comm.).
Georgetown Salamander
Little is known about the reproductive habits of this species.
However, the Georgetown salamander is fully aquatic, and therefore
spends all of its life cycles in aquifer and spring waters. Eggs of
central Texas Eurycea are rarely seen on the surface, so it is widely
assumed that eggs are laid underground (Gluesenkamp 2011a, pers. comm.;
Bendik 2011b, pers. comm.).
Salado Salamander
Little is known about the reproductive habits of this species.
However, the Salado salamander is fully aquatic, and therefore spends
all of its life cycles in aquifer and spring waters. Eggs of central
Texas Eurycea are rarely seen on the surface, so it is widely assumed
that eggs are laid underground (Gluesenkamp 2011a, pers. comm.; Bendik
2011b, pers. comm.).
Primary Constituent Elements for the Four Central Texas Salamanders
Under the Act and its implementing regulations, we are required to
identify the physical or biological features essential to the
conservation of the salamander species in areas occupied at the time of
listing, focusing on the features' primary constituent elements. We
consider primary constituent elements to be the elements of physical or
biological features that are essential to the conservation of the
species.
Based on our current knowledge of the physical or biological
features and habitat characteristics required to sustain the species'
life-history processes, we determine that the primary constituent
elements specific to these salamander species are surface springs,
underground streams, and wet caves containing:
Austin Blind Salamander
1. Water from the Barton Springs Segment of the Edwards Aquifer.
The
[[Page 50809]]
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Austin blind salamander's prey base). Hydrologic regimes
similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow from the spring sites and
continuous flow in the subterranean habitat. The water chemistry must
be similar to natural aquifer conditions, with temperatures between
67.8 and 72.3[emsp14][deg]F (19.9 and 22.4 [deg]C), dissolved oxygen
concentrations between 5 and 7 mg L-1, and specific water
conductance between 605 and 740 [micro]S cm-1.
2. Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat should be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
should have minimal sedimentation.
3. Aquatic invertebrates for food. The spring and cave environments
should be capable of supporting a diverse aquatic invertebrate
community that includes crustaceans and insects.
4. Subterranean aquifer. During periods of drought or dewatering on
the surface in and around spring sites, access to the subsurface water
table must exist to provide shelter and protection.
Jollyville Plateau Salamander
1. Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Jollyville Plateau salamander's prey base). Hydrologic
regimes similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow in subterranean habitats. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 65.3
and 67.3 [deg]F (18.5 and 19.6 [deg]C), dissolved oxygen concentrations
between 5.6 and 7.1 mg L-1, and specific water conductance
between 550 and 625 [mu]S cm-1.
2. Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat should be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
should have minimal sedimentation.
3. Aquatic invertebrates for food. The spring and cave environments
should be capable of supporting a diverse aquatic invertebrate
community that includes crustaceans and insects.
4. Subterranean aquifer. During periods of drought or dewatering on
the surface in and around spring sites, access to the subsurface water
table must exist to provide shelter and protection.
Georgetown Salamander
1. Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Georgetown salamander's prey base). Hydrologic regimes
similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow for subterranean sites. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 68.4
and 69.8 [deg]F (20.2 and 21.0 [deg]C), dissolved oxygen concentrations
between 6 and 8 mg L-1, and specific water conductivity
between 604 and 721 [mu]S cm-1.
2. Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat should be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
should have minimal sedimentation.
3. Aquatic invertebrates for food. The spring and cave environments
should be capable of supporting a diverse aquatic invertebrate
community that includes crustaceans and insects.
4. Subterranean aquifer. During periods of drought or dewatering on
the surface in and around spring sites, access to the subsurface water
table must exist to provide shelter and protection.
Salado Salamander
1. Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Salado salamander's prey base). Hydrologic regimes
similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow for subterranean sites. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 65.3
and 69.8 [deg]F (18.5 and 21.0 [deg]C), dissolved oxygen concentrations
between 5.6 and 8 mg L-1, and conductivity between 550 and
721 [mu]S cm-1. The best scientific evidence available
suggests that the groundwater of Salado salamander habitat is the same
as Georgetown and Jollyville Plateau salamander habitat in terms of
chemistry. Therefore, we include here for the Salado salamander the
range of water chemistry parameters that encompass the ranges found in
Jollyville and Georgetown salamander habitats.
2. Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat should be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
should have minimal sedimentation.
3. Aquatic invertebrates for food. The spring and cave environments
should be capable of supporting a diverse aquatic invertebrate
community that includes crustaceans and insects.
4. Subterranean aquifer. During periods of drought or dewatering on
the surface in and around spring sites, access to the subsurface water
table should be provided for shelter and protection.
With this proposed designation of critical habitat, we intend to
identify the physical or biological features essential to the
conservation of the species, through the identification of the primary
constituent elements sufficient to support the life-history processes
of the species. All units and subunits
[[Page 50810]]
proposed to be designated as critical habitat are currently occupied by
one of the four salamander species and contain the primary constituent
elements sufficient to support the life-history needs of the species.
Special Management Considerations or Protection
When designating critical habitat, we assess whether the specific
areas within the geographical area occupied by the species at the time
of listing contain features which are essential to the conservation of
the species and which may require special management considerations or
protection. The features essential to the conservation of this species
may require special management considerations or protection to reduce
the following threats: Water quality degradation from contaminants,
alteration to natural flow regimes, and physical habitat modification.
For these salamanders, special management considerations or
protection are needed to address threats. Management activities that
could ameliorate threats include (but are not limited to): (1)
Protecting the quality of cave and spring water by implementing
comprehensive programs to control and reduce point sources and non-
point sources of pollution throughout the Barton Springs and Northern
Segments of the Edwards Aquifer, (2) minimizing the likelihood of
pollution events that would affect groundwater quality, (3) protecting
groundwater and spring flow quantity (for example, by implementing
water conservation and drought contingency plans throughout the Barton
Springs and Northern Segments), and (4) excluding cattle and feral hogs
through fencing to protect spring habitats from damage.
Criteria Used To Identify Critical Habitat
As required by section 4(b)(1)(A) of the Act, we use the best
scientific data available in determining areas that contain the
features that are essential to the conservation of the Austin blind,
Jollyville Plateau, Georgetown, and Salado salamanders. During our
preparation for proposing critical habitat for the four salamander
species, we have reviewed: (1) Data for historical and current
occurrence, (2) information pertaining to habitat features essential
for the conservation of these species, and (3) scientific information
on the biology and ecology of the four species. We have also reviewed a
number of studies and surveys of the four salamander species that
confirm historical and current occurrence of the four species
including, but not limited to, Sweet (1978; 1982), COA (2001),
Chippindale et al. (2000), and Hillis et al. (2001). Finally,
salamander site locations and observations were verified with the aid
of salamander biologists, museum collection records, and site visits.
In accordance with the Act and its implementing regulation at 50
CFR 424.12(e), we consider whether designating additional areas--
outside those currently occupied as well as those occupied at the time
of listing--are necessary to ensure the conservation of the species. We
are not currently proposing to designate any additional areas outside
the geographical area occupied by the species, because the occupied
habitats proposed for critical habitat are sufficient for the
conservation of the species. For the purpose of designating critical
habitat for the four central Texas salamander species, we define an
area as occupied based upon the reliable observation of a salamander
species by a knowledgeable scientist. It is very difficult to prove
unquestionably that a salamander population has been extirpated from a
spring site due to these species' ability to occupy the inaccessible
subsurface habitat. We therefore considered any site that had a
salamander observation at any point in time currently occupied, unless
that spring or cave site had been destroyed.
Based on our review, the proposed critical habitat areas described
below constitute our best assessment at this time of areas that are
within the geographical range occupied by at least one of the four
salamander species, and are considered to contain features essential to
the conservation of these species. The extent to which the subterranean
populations of these species exist belowground away from outlets of the
spring system is unknown. Because the hydrology of central Texas is
very complex and information on the hydrology of specific spring sites
are largely unknown, we will be seeking information on spring hydrology
and salamander underground distribution during our public comment
period (see DATES). However, at the time of this proposed listing rule,
the best scientific evidence available suggests that the population of
these salamanders can extend at least 984 ft (300 m) from the spring
opening through underground conduits.
We are proposing for designation of critical habitat lands that we
have determined are occupied by at least one of the four salamanders
and contain sufficient elements of physical or biological features to
support life-history processes essential for the conservation of the
species. We delineated both surface and subsurface critical habitat
components. The surface critical habitat component was delineated by
starting with the cave or spring point locations that are occupied by
the salamanders and extending a line downstream 164 ft (50 m) because
this is the farthest a salamander has been observed from a spring
outlet. The surface critical habitat includes the spring outlets and
outflow up to the high water line and 164 ft (50 m) of downstream
habitat, but does not include manmade structures (such as buildings,
aqueducts, runways, roads, and other paved areas); however, the
subterranean aquifer may extend below such structures. We delineated
the subsurface critical habitat unit boundaries by starting with the
cave or spring point locations that are occupied by the salamanders.
From these cave or springs points, we delineated a 984-ft (300-m)
buffer to create the polygons that capture the extent to which we
believe the salamander populations exist through underground conduits.
The polygons were then simplified to reduce the number of vertices, but
still retain the overall shape and extent. Once that was done, polygons
that were within 98 ft (30 m) of each other were merged together
because these areas are likely connected underground. Each new merged
polygon was then revised by removing extraneous divits or protrusions
that resulted from the merge process.
When determining proposed critical habitat boundaries, we made
every effort to avoid including developed areas, such as lands covered
by buildings, pavement, and other structures, because such lands lack
physical or biological features essential for the conservation of the
four central Texas salamanders. The scale of the maps we prepared under
the parameters for publication within the Code of Federal Regulations
may not reflect the exclusion of such developed lands. Any such lands
inadvertently left inside critical habitat boundaries shown on the maps
of this proposed rule have been excluded by text in the proposed rule,
and are not proposed for designation as critical habitat. Therefore, if
the critical habitat is finalized as proposed, a Federal action
involving these lands would not trigger section 7 consultation with
respect to critical habitat and the requirement of no adverse
modification unless the specific action would affect the physical or
biological features in the underground or adjacent critical habitat.
The critical habitat designation is defined by the map or maps, as
[[Page 50811]]
modified by any accompanying regulatory text, presented at the end of
this document in the rule portion. We include more detailed information
on the boundaries of the critical habitat designation in the preamble
of this document. We will make the coordinates or plot points or both
on which each map is based available to the public on http://regulations.gov at Docket No. FWS-R2-ES-2012-0035, on our Internet site
at http://www.fws.gov/southwest/es/AustinTexas/, and at the field
office responsible for the designation (see FOR FURTHER INFORMATION
CONTACT above).
Proposed Critical Habitat Designation
We are proposing a total of 52 units for designation for the 4
central Texas salamanders based on sufficient elements of physical or
biological features being present to support the Austin blind,
Jollyville Plateau, Georgetown, and Salado salamanders' life-history
processes. Some units contain all of the identified elements of
physical or biological features and support multiple life-history
processes. Some units contain only some elements of the physical or
biological features necessary to support the four central Texas
salamanders' particular use of that habitat. In some units, the
physical or biological features essential for the conservation of these
salamanders have been impacted at times, and in some cases these
impacts have had negative effects on the salamander populations there.
We recognize that some units have experienced impacts and may have
physical or biological features of lesser quality than others. Special
management or protection is needed at these sites to restore the
physical or biological features to provide for long-term sustainability
of the species at these sites. In addition, high-quality sites need
special protection, and in some cases management, to maintain their
quality and ability to sustain the salamander populations over the long
term.
We are proposing 1 unit as critical habitat for the Austin blind
salamander, 33 units as critical habitat for the Jollyville Plateau
salamander, 14 units as critical habitat for the Georgetown salamander,
and 4 units as critical habitat for the Salado salamander (52 units
total). The critical habitat areas we describe below constitute our
current best assessment of areas that meet the definition of critical
habitat for the four salamander species. As previously noted, we are
proposing both surface and subsurface critical habitat components. The
surface critical habitat includes the spring outlets and outflow up to
the high water line and 164 ft (50 m) of downstream habitat, but does
not include manmade structures (such as buildings, aqueducts, runways,
roads, and other paved areas); however, the subterranean aquifer may
extend below such structures. The subsurface critical habitat includes
underground features in a circle with a radius of 984 ft (300 m) around
the springs. The 52 units we propose as critical habitat are listed and
described below, and acreages are based on the size of the subsurface
critical habitat component. All units described below are occupied by
one of the four salamander species.
Table 7--Proposed Critical Habitat Unit for the Austin Blind Salamander
----------------------------------------------------------------------------------------------------------------
Critical habitat unit Land ownership by type Size of unit in acres (hectares)
----------------------------------------------------------------------------------------------------------------
1. Barton Springs Unit................... City, Private............... 120 (49).
----------------------------------------
Total................................ ............................ 120 ac (49 ha).
----------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding. Area estimates reflect all land within critical habitat unit
boundaries.
Table 8--Proposed Critical Habitat Units for the Jollyville Plateau Salamander
----------------------------------------------------------------------------------------------------------------
Critical habitat unit Land ownership by type Size of unit in acres (hectares)
----------------------------------------------------------------------------------------------------------------
1. Krienke Spring Unit................... Private..................... 68 (28).
2. Brushy Creek Spring Unit.............. Private..................... 68 (28).
3. Testudo Tube Cave Unit................ Private, City............... 68 (28).
4. Buttercup Creek Cave Unit............. Private..................... 227 (92).
5. Treehouse Cave Unit................... Private..................... 68 (28).
6. Avery Spring Unit..................... Private..................... 237 (96).
7. PC Spring Unit........................ Private..................... 68 (28).
8. Baker and Audubon Spring Unit......... Private..................... 110 (45).
9. Wheless Spring Unit................... Private, County............. 135 (55).
10. Blizzard R-Bar-B Spring Unit......... Private..................... 68 (28).
11. House Spring Unit.................... Private..................... 68 (28).
12. Kelly Hollow Spring Unit............. Private..................... 68 (28).
13. MacDonald Well Unit.................. Private, County............. 68 (28).
14. Kretschmarr Unit..................... Private, County............. 112 (45).
15. Pope and Hiers (Canyon Creek) Spring Private..................... 68 (28).
Unit.
16. Fern Gully Spring Unit............... Private, City............... 68 (28).
17. Bull Creek 1 Unit.................... Private, City, County....... 1,157 (468).
18. Bull Creek 2 Unit.................... Private, City, County....... 237 (96).
19. Bull Creek 3 Unit.................... Private, City............... 254 (103).
20. Moss Gulley Spring Unit.............. City, County................ 68 (28).
21. Ivanhoe Spring Unit.................. City........................ 68 (28).
22. Sylvia Spring Unit................... Private, City, County....... 103 (42).
23. Tanglewood Spring Unit............... Private..................... 68 (28).
24. Long Hog Hollow Unit................. Private..................... 68 (28).
25. Tributary 3 Unit..................... Private..................... 68 (28).
26. Sierra Spring Unit................... Private..................... 68 (28).
27. Troll Spring Unit.................... Private..................... 98 (40).
28. Stillhouse Unit...................... Private..................... 203 (82).
[[Page 50812]]
29. Salamander Cave Unit................. Private..................... 68 (28).
30. Indian Spring Unit................... Private..................... 68 (28).
31. Spicewood Spring Unit................ Private..................... 68 (28).
32. Balcones District Park Spring Unit... Private, City............... 68 (28).
33. Tributary 4 Unit..................... Private, City............... 159 (64).
----------------------------------------
Total................................ ............................ 4,460 ac (1,816 ha).
----------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding. Area estimates reflect all land within critical habitat unit
boundaries.
Table 9--Proposed Critical Habitat Units for the Georgetown Salamander
----------------------------------------------------------------------------------------------------------------
Critical habitat unit Land ownership by type Size of unit in acres (hectares)
----------------------------------------------------------------------------------------------------------------
1. Cobb Unit............................. Private..................... 83 (34)
2. Cowen Creek Spring Unit............... Private..................... 68 (28).
3. Bat Well Unit......................... Private..................... 68 (28).
4. Walnut Spring Unit.................... Private, County............. 68 (28).
5. Twin Springs Unit..................... Private, County............. 68 (28).
6. Hogg Hollow Spring Unit............... Private, Federal............ 68 (28).
7. Cedar Hollow Spring Unit.............. Private..................... 68 (28).
8. Lake Georgetown Unit.................. Federal, Private............ 132 (53).
9. Water Tank Cave Unit.................. Private..................... 68 (28).
10. Avant Spring Unit.................... Private..................... 68 (28).
11. Buford Hollow Spring Unit............ Federal, Private............ 68 (28).
12. Swinbank Spring Unit................. City, Private............... 68 (28).
13. Shadow Canyon Unit................... City, Private............... 68 (28).
14. San Gabriel Springs Unit............. City........................ 68 (28).
----------------------------------------
Total................................ ............................ 1,031 ac (423 ha).
----------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding. Area estimates reflect all land within critical habitat unit
boundaries.
Table 10--Proposed Critical Habitat Units for the Salado Salamander
----------------------------------------------------------------------------------------------------------------
Critical habitat unit Land ownership by type Size of unit in acres (hectares)
----------------------------------------------------------------------------------------------------------------
1. Hog Hollow Spring Unit................ Private..................... 68 (28)
2. Solana Spring 1 Unit......... Private..................... 68 (28).
3. Cistern Spring Unit................... Private..................... 68 (28).
4. IH-35 Unit............................ Private, State, City........ 168 (68).
----------------------------------------
Total................................ ............................ 372 ac (152 ha).
----------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding. Area estimates reflect all land within critical habitat unit
boundaries.
We present brief descriptions of all units, and reasons why they
meet the definition of critical habitat for the four central Texas
salamanders, below.
Austin Blind Salamander
Unit 1: Barton Springs Unit
The Barton Springs Unit consists of 120 ac (49 ha) of City and
private land in the City of Austin, central Travis County, Texas. Most
of the unit is located in Zilker Park, which is owned by the City of
Austin. Most of the unit consists of landscaped areas managed as a
public park. The southwestern portion of the unit is dense commercial
development, and part of the southern portion contains residential
development. Barton Springs Road, a major roadway, crosses the
northeastern portion of the unit. This unit contains Parthenia Spring,
Sunken Gardens Spring, and Eliza Spring, which are occupied by Austin
blind salamander. The springs are located in the Barton Creek
watershed. Parthenia Spring is located in the backwater of Barton
Springs Pool, which is formed by a dam on Barton Creek; Eliza Spring is
on an unnamed tributary to the bypass channel of the pool; and Sunken
Gardens Spring is located on a tributary that enters Barton Creek
downstream of the dam for Barton Springs Pool. The unit contains all of
the primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
contributing and recharge zone for the Barton Springs segment of the
Edwards Aquifer and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the underground aquifer in this
area and the springs and fissure outlets. The unit was further
delineated by drawing a circle with a radius of 984 ft (300 m) around
the springs, representing the extent of the subterranean critical
habitat. We joined the edges of the resulting circles. Because we did
not have specific points for species locations, we used the center of
Eliza and Sunken Gardens springs and the southwestern point of a
fissure in Parthenia Springs.
[[Page 50813]]
Jollyville Plateau Salamander
Unit 1: Krienke Spring Unit
Unit 1 consists of 68 ac (28 ha) of private land in southern
Williamson County, Texas. The unit is located just south of State
Highway 29. The northern part of the unit is in dense residential
development, while the southern part of the unit is less densely
developed. County Road 175 (Sam Bass Road) crosses the northern half of
the unit. This unit contains Krienke Spring, which is occupied by the
Jollyville Plateau salamander. The spring is located on an unnamed
tributary of Dry Fork, a tributary to Brushy Creek. The unit contains
all the primary constituent elements essential for the conservation of
the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 2: Brushy Creek Spring Unit
Unit 2 consists of 68 ac (28 ha) of private land in southern
Williamson County, Texas. The unit is centered just south of Palm
Valley Boulevard and west of Grimes Boulevard. The northern part of the
unit is covered with commercial and residential development, while the
southern part is less densely developed. Some areas along the stream
are undeveloped. This unit contains Brushy Creek Spring, which is
occupied by the Jollyville Plateau salamander. The spring is near
Brushy Creek. The unit contains all the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 3: Testudo Tube Cave Unit
Unit 3 consists of 68 ac (28 ha) of City of Austin and private land
in southern Williamson County and northern Travis County, Texas. The
unit is located just east of Lime Creek Road. The unit is mostly
undeveloped but several unpaved roads cross it. This unit contains
Testudo Tube Cave, which is occupied by the Jollyville Plateau
salamander. The cave and the surrounding area are owned by the City of
Austin as water quality protection land. The cave contains the Tooth
Cave ground beetle (Rhadine persephone), an endangered karst
invertebrate. As part of the mitigation for the Lakeline Mall HCP, the
cave must be protected and managed in perpetuity. These actions will
provide some benefit to the Jollyville Plateau salamander. The unit
contains all the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the cave. The unit was further
delineated by drawing a circle with a radius of 984 ft (300 m) around
the cave, representing the extent of the subterranean critical habitat.
Unit 4: Buttercup Creek Cave Unit
Unit 4 consists of 227 ac (92 ha) of private land in southern
Williamson County, Texas. The unit is located east and south of the
intersection of Lakeline Boulevard and Buttercup Creek Boulevard. The
unit is mostly covered with residential property. Lakeline Boulevard, a
major thoroughfare, crosses the northeast area of the unit. An
undeveloped area of parks and setbacks is in the south central part of
the unit. This unit contains four caves: TWASA Cave, Illex Cave,
Buttercup Creek Cave, and Flea Cave, which are occupied by the
Jollyville Plateau salamander. The three latter caves are located in a
preserve set up as mitigation property under the Buttercup HCP. The HCP
covers adverse impacts to the Tooth Cave ground beetle. Although the
salamander is not covered under the Buttercup HCP, the protection
afforded these caves by the HCP provides some benefit for the species.
The unit contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Buttercup HCP, and impacts to the Tooth Cave ground beetle
are permitted (Service 1999, p. 1). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the caves. The unit was further
delineated by drawing a circle with a radius of 984 ft (300 m) around
the caves, representing the extent of the subterranean critical
habitat. We joined the edges of the resulting circles.
Unit 5: Treehouse Cave Unit
Unit 5 consists of 68 ac (28 ha) of private land in southern
Williamson County, Texas. The unit is located east of the intersection
of Buttercup Creek Boulevard and Sycamore Drive. Most of the unit is
covered with moderately dense residential development. A small park is
close to the center of the unit, and a greenbelt crosses the unit from
east to west. This unit contains Treehouse Cave, which is occupied by
the Jollyville Plateau salamander. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the cave. The unit was further
delineated by drawing a circle with a radius of 984 ft (300 m) around
the cave, representing the extent of the subterranean critical habitat.
Unit 6: Avery Spring Unit
Unit 6 consists of 237 ac (96 ha) of private land in southern
Williamson County, Texas. The unit is located north of Avery Ranch
Boulevard and west of Parmer Lane. The unit has large areas covered by
residential development. The developed areas are separated by fairways
and greens of a golf course. This unit contains three springs: Avery
Springhouse Spring, Hill Marsh Spring, and Avery Deer Spring, which are
occupied by the Jollyville Plateau salamander. The springs are located
on an unnamed tributary to South Brushy Creek. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater
[[Page 50814]]
pollution from current and future development in the watershed,
potential for vandalism, and depletion of groundwater (see Special
Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the three springs, representing the extent of the
subterranean critical habitat. We joined the edges of the resulting
circles.
Unit 7: PC Spring Unit
Unit 7 consists of 68 ac (28 ha) of private and public land in
southern Williamson County, Texas. State Highway 45, a major toll road,
crosses the north central part of the unit from east to west, and Ranch
to Market Road 620 goes under it midway between the center and the
western edge. Except for roadways, the unit is undeveloped. This unit
contains PC Spring, which is occupied by the Jollyville Plateau
salamander. The spring is located on Davis Spring Branch. The unit
contains the primary constituent elements essential for the
conservation of species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 8: Baker and Audubon Spring Unit
Unit 8 consists of 110 ac (45 ha) of private and Lower Colorado
River Authority (LCRA) land in northern Travis County, Texas. The unit
is located south of Lime Creek Road and southwest of the intersection
of Canyon Creek Drive and Lime Springs Road. The unit is wooded,
undeveloped, and owned by Travis Audubon Society and LCRA. The entire
unit is managed as part of the Balcones Canyonlands HCP. This unit
contains two springs, Baker Spring and Audubon Spring, which are
occupied by the Jollyville Plateau salamander. The springs are in the
drainage of an unnamed tributary to Cypress Creek. The unit contains
the primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Balcones Canyonlands Preserve HCP, and impacts to 35 species
are permitted (Service 1996b, p. 3). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Unit 9: Wheless Spring Unit
Unit 9 consists of 135 ac (55 ha) of private LCRA and Travis County
land in northern Travis County, Texas. The unit is located about 0.8 mi
(1.3 km) west of Grand Oaks Loop. The unit is wooded and consists of
totally undeveloped land owned by LCRA and The Nature Conservancy. The
unit is managed as part of the Balcones Canyonlands Preserve HCP. An
unpaved road crosses the unit from north to south. This unit contains
two springs, Wheless Spring and Spring 25, which are occupied by the
Jollyville Plateau salamander. The springs are in the Long Hollow Creek
drainage. The unit contains the primary constituent elements essential
for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, habitat disturbance by feral hogs,
and depletion of groundwater (see Special Management Considerations or
Protection section). The unit is within the Balcones Canyonlands
Preserve HCP, and impacts to 35 species are permitted (Service 1996b,
p. 3). However, impacts to the Jollyville Plateau salamander are not
covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Unit 10: Blizzard R-Bar-B Spring Unit
Unit 10 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is located west of Grand Oaks Loop. The
extreme eastern portion of the unit is on the edge of residential
development; a golf course (Twin Springs) crosses the central portion;
and the remainder is wooded and undeveloped. This unit contains
Blizzard R-Bar-B Spring, which is occupied by the Jollyville Plateau
salamander. The spring is located on Cypress Creek. The unit contains
the primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 11: House Spring Unit
Unit 11 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is located just north of Benevento Way
Road. Dies Ranch Road crosses the extreme eastern part of the unit. The
entire unit is covered with dense residential development except for a
narrow corridor along the stream, which crosses the unit from north to
south. Several streets are located in the unit. This unit contains
House Spring, which is occupied by the Jollyville Plateau salamander.
The spring is located on an unnamed tributary to Lake Marble Falls. The
unit contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 12: Kelly Hollow Spring Unit
Unit 12 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is located southeast of the intersection
of Anderson Mill Road and Farm to Market Road 2769. With
[[Page 50815]]
the exception of a portion of Anderson Mill Road along the northern
edge of the unit, this unit is primarily undeveloped woodland. This
unit contains Kelly Hollow Spring, which is occupied by the Jollyville
Plateau salamander. The spring is located on an unnamed tributary to
Lake Marble Falls. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 13: MacDonald Well Unit
Unit 13 consists of 68 ac (28 ha) of private and Travis County land
in northern Travis County, Texas. The unit is centered near the
intersection of Grand Oaks Loop and Farm to Market Road 2769. Farm to
Market Road 2769 crosses the unit slightly north of its center. The
northern portion of the unit contains residential development and part
of Twin Creeks Golf Course. This unit contains MacDonald Well, which is
occupied by the Jollyville Plateau salamander. The spring is located on
an unnamed tributary to Lake Marble Falls. The unit contains the
primary constituent elements essential for the conservation of the
species. The spring and adjacent land are protected and monitored as
part of the Balcones Canyonlands Preserve HCP.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Balcones Canyonlands Preserve HCP, and impacts to 35 species
are permitted (Service 1996b, p. 3). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 14: Kretschmarr Unit
Unit 14 consists of 112 ac (45 ha) of private and Travis County
land in northern Travis County, Texas. The unit is located west of
Ranch to Market Road 620. Wilson Parke Avenue crosses the unit along
its southern border. Most of the unit is undeveloped, with one
commercial development near the west central portion. Some of the unit
is owned and managed by Travis County as part of the Balcones
Canyonlands Preserve. This unit contains three springs: Kretschmarr
Salamander Cave, Unnamed Tributary Downstream of Grandview, and SAS
Canyon, which are occupied by the Jollyville Plateau salamander. The
unit contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We connected the edges of the resulting circles.
Unit 15: Pope and Hiers (Canyon Creek) Spring Unit
Unit 15 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is located between Bramblecrest Drive
and Winchelsea Drive. The unit contains dense residential development
on its northern, eastern, and western portions. The central portion of
the unit is an undeveloped canyon and is preserved in perpetuity as
part of a private preserve. This unit contains Canyon Creek Pope and
Hiers Spring, which is occupied by the Jollyville Plateau salamander.
The spring is located on Bull Creek Tributary 6. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 16: Fern Gully Spring Unit
Unit 16 consists of 68 ac (28 ha) of private and City of Austin
land in northern Travis County, Texas. The unit is centered just south
of the intersection of Jenaro Court and Boulder Lane. The unit contains
dense residential development on much of its northern half. Most of the
southern half of the unit is undeveloped land managed by the City of
Austin as part of the Balcones Canyonlands Preserve HCP, and a portion
is part of the Canyon Creek preserve, a privately managed conservation
area. This unit contains Fern Gully Spring, which is occupied by the
Jollyville Plateau salamander. The spring is located on Bull Creek
Tributary 5. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Balcones Canyonlands Preserve HCP, and impacts to 35 species
are permitted (Service 1996b, p. 3). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 17: Bull Creek 1 Unit
Unit 17 consists of 1,157 ac (468 ha) of private, City of Austin,
and Travis County land in northern Travis County, Texas. The unit
extends from the southeastern portion of Chestnut Ridge Road to 3M
Center, just north of Ranch to Market Road 2222. The unit contains some
residential development on the extreme edge of its northern portion and
part of Vandegrift High School near its southeastern corner. Most of
the remainder of the unit is undeveloped land managed by the City of
Austin and Travis County as part of the Balcones Canyonlands Preserve
HCP. This unit contains the following 34 springs: Tubb Spring, Broken
Bridge Spring, Spring 17, Tributary No. 5, Tributary 6 at Sewage Line,
Canyon Creek, Tributary No. 6, Gardens of Bull Creek, Canyon
[[Page 50816]]
Creek Hog Wallow Spring, Spring 5, Franklin, Pit Spring, Bull Creek
Spring Pool, Spring 1, Spring 4, Spring 2, Lanier Spring, Cistern
(Pipe) Spring, Spring 3, Lanier 90-foot Riffle, Bull Creek at Lanier
Tract, Ribelin/Lanier, Spring 18, Horsethief, Ribelin, Spring 15,
Spring 16, Spring 14, Lower Ribelin, Spring 13, Spring 12, Upper
Ribelin, Spring 10, and Spring 9. These springs are occupied by the
Jollyville Plateau salamander and are located on Bull Creek and its
tributaries. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, habitat destruction by feral hogs,
and depletion of groundwater (see Special Management Considerations or
Protection section). The unit is within the Balcones Canyonlands
Preserve HCP, and impacts to 35 species are permitted (Service 1996b,
p. 3). However, impacts to the Jollyville Plateau salamander are not
covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Unit 18: Bull Creek 2 Unit
Unit 18 consists of 237 ac (96 ha) of private, City of Austin, and
Travis County land in northern Travis County, Texas. The center of the
unit is near the eastern end of Concordia University Drive. Concordia
University is in the central and eastern parts of the unit. Much of the
rest of the unit is undeveloped land managed by the City of Austin and
Travis County as part of the Balcones Canyonlands Preserve HCP. This
unit contains six springs: Schlumberger Spring No. 1, Schlumberger
Spring No. 2, Schlumberger Spring No. 6, Schlumberger Spring No. 19,
Concordia Spring X, and Concordia Spring Y, which are occupied by the
Jollyville Plateau salamander. The springs are located on Bull Creek
Tributary 7. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Balcones Canyonlands Preserve HCP, and impacts to 35 species
are permitted (Service 1996b, p. 3). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Unit 19: Bull Creek 3 Unit
Unit 19 consists of 254 ac (103 ha) of private and City of Austin
land in northern Travis County, Texas. The unit is just southeast of
the intersection of Ranch to Market Road 620 and Vista Parke Drive. The
unit contains dense residential development on much of its northern
half. Most of the rest of the unit (about 134 ac (54.2 ha)) is
undeveloped land managed by as part of the Four Points HCP. Much of the
remainder of the unit is managed by the City of Austin as part of the
Balcones Canyonlands Preserve HCP. This unit contains five springs:
Spring No. 21, Spring No. 22, Spring No. 24, Hamilton Reserve West, and
Gaas Spring, which are occupied by the Jollyville Plateau salamander.
The springs are located on Bull Creek. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets up to the high
water line and 164 ft (50 m) of downstream habitat. The unit was
further delineated by drawing a circle with a radius of 984 ft (300 m)
around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles. Under
section 4(b)(2) of the Act, certain lands in this unit are being
considered for exclusion from the final rule for critical habitat (see
Application of Section 4(b)(2) of the Act section below).
Unit 20: Moss Gulley Spring Unit
Unit 20 consists of 68 ac (28 ha) of City of Austin and Travis
County land in northern Travis County, Texas. The unit is just east of
the eastern end of Unit 19. The unit is all undeveloped woodland, and
all is managed by the City of Austin or Travis County as part of the
Balcones Canyonlands Preserve HCP. This unit contains Moss Gulley
Spring, which is occupied by the Jollyville Plateau salamander. The
spring is located on Bull Creek. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section). The unit is
within the Balcones Canyonlands Preserve HCP, and impacts to 35 species
are permitted (Service 1996b, p. 3). However, impacts to the Jollyville
Plateau salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 21: Ivanhoe Spring Unit
Unit 21 consists of 68 ac (28 ha) of City of Austin land in
northern Travis County, Texas. The unit is east of the northwest extent
of High Hollow Drive. The unit is all undeveloped woodland, and is
managed by the City of Austin as part of the Balcones Canyonlands
Preserve HCP. This unit contains Ivanhoe Spring 2, which is occupied by
the Jollyville Plateau salamander. The spring is located on West Bull
Creek. The unit contains the primary constituent elements essential for
the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, destruction of habitat by feral
hogs, and depletion of groundwater (see Special Management
Considerations or Protection section). The unit is within the Balcones
Canyonlands Preserve HCP, and impacts to 35 species are permitted
(Service 1996b, p. 3). However, impacts to the Jollyville Plateau
salamander are not covered under this HCP.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
[[Page 50817]]
Unit 22: Sylvia Spring Unit
Unit 22 consists of 103 ac (42 ha) of private, City, and Williamson
County land in northern Travis County and southwestern Williamson
County, Texas. The unit is centered just east of the intersection
Callanish Park Drive and Westerkirk Drive. The western, extreme
northeastern, and extreme southern portions of the unit are residential
development. An undeveloped stream corridor crosses the unit from north
to south. This unit contains two springs: Small Sylvia Spring and
Spicewood Valley Park Spring, which are occupied by the Jollyville
Plateau salamander. The springs are located on an unnamed tributary to
Tanglewood Creek. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Unit 23: Tanglewood Spring Unit
Unit 23 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered north of the intersection of
Spicewood Springs Road and Yaupon Drive. Spicewood Springs Road crosses
the unit from southwest to east. Residential and commercial development
is found in most of the unit except in a stream corridor in the central
part of the unit. An undeveloped stream corridor crosses the unit from
east to west. This unit contains Tanglewood Spring, which is occupied
by the Jollyville Plateau salamander. The spring is located on
Tanglewood Creek, a tributary to Bull Creek. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 24: Long Hog Hollow Unit
Unit 24 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered east of the intersection of
Cassia Drive and Fireoak Drive. Most of the unit is in residential
development. There are wooded corridors in the central and eastern
portion of the unit. This unit contains Long Hog Hollow Tributary,
which is occupied by the Jollyville Plateau salamander. The spring is
located on Long Hog Hollow Tributary. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 25: Tributary 3 Unit
Unit 25 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered between Bluegrass Drive and
Spicebush Drive. The eastern and western part of the unit is in
residential development. There are wooded corridors in the central part
of the unit, and scattered woodland in the eastern and western part.
There is a golf course in the north-central part of the unit. This unit
contains Tributary No. 3, which is occupied by the Jollyville Plateau
salamander. The spring is located on Bull Creek Tributary 3. The unit
contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 26: Sierra Spring Unit
Unit 26 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is located west of the intersection of
Tahoma Place and Ladera Vista Drive. The eastern and western part of
the unit is in residential development. A wooded corridor crosses the
central part of the unit from north to south. This unit contains Sierra
Spring, which is occupied by the Jollyville Plateau salamander. The
spring is located on Bull Creek Tributary 3. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 27: Troll Spring Unit
Unit 27 consists of 98 ac (40 ha) of private land in northern
Travis County, Texas. The unit is located west of the intersection of
Jollyville Road and Taylor Draper Lane. The eastern and western part of
the unit is in residential development. A wooded corridor crosses the
central part of the unit from north to south. This unit contains two
springs, Hearth Spring and Troll Spring, which are occupied by the
Jollyville Plateau salamander. The springs are located on Bull Creek
Tributary 3. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets up to the high
water line and 164 ft (50 m) of downstream habitat. The unit was
further delineated by drawing a circle with a radius of 984 ft (300 m)
around the springs, representing the extent of the subterranean
critical habitat. We
[[Page 50818]]
connected the edges of the resulting circles.
Unit 28: Stillhouse Unit
Unit 28 consists of 203 ac (82 ha) of private land in northern
Travis County, Texas. The unit is centered due north of the
intersection of West Rim Drive and Burney Drive. The northern and
southern part of the unit is in residential development. A wooded
corridor crosses the central part of the unit from east to west. This
unit contains seven springs: Barrow Hollow Spring, Spring 20,
Stillhouse Hollow Tributary, Stillhouse Tributary, Little Stillhouse
Hollow Spring, Stillhouse Hollow Spring, and Barrow Preserve Tributary.
All are occupied by the Jollyville Plateau salamander. The springs are
located on an unnamed tributary to Bull Creek. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflows
up to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We connected the edges of the resulting circles.
Unit 29: Salamander Cave Unit
Unit 29 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered near the southern end of
Raintree Place, just north of Spicewood Springs Road. Most of the unit
is covered with commercial and residential development, except for a
small portion of wooded area near the center. A wooded corridor crosses
the central part of the unit from east to west. This unit contains
Salamander Cave, which is occupied by the Jollyville Plateau
salamander. The spring is located on an unnamed tributary to Shoal
Creek. The unit contains the primary constituent elements essential for
the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 30: Indian Spring Unit
Unit 30 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered just south of Greystone
Drive about half way between its intersection with Edgerock Drive and
Chimney Corners Drive. Most of the unit is covered with residential
development except for a small wooded corridor that crosses the central
part of the unit from east to west. This unit contains Indian Spring,
which is occupied by the Jollyville Plateau salamander. The spring is
located on an unnamed tributary to Shoal Creek. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 31: Spicewood Spring Unit
Unit 31 consists of 68 ac (28 ha) of private land in northern
Travis County, Texas. The unit is centered just northeast of the
intersection of Ceberry Drive and Spicewood Springs Road, just
downstream of the bridge on Ceberry Drive. Most of the unit is covered
with commercial and residential development except for a small wooded
corridor along the stream, which crosses the unit from north to east.
This unit contains two springs, Spicewood Spring and Spicewood
Tributary, which are occupied by the Jollyville Plateau salamander. The
springs are located in an unnamed tributary to Shoal Creek. The unit
contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 32: Balcones District Park Spring Unit
Unit 32 consists of 68 ac (28 ha) of City of Austin and private
land in northern Travis County, Texas. The unit is centered about 470
yards (430 m) northeast of the intersection of Duval Road and Amherst
Drive. Most of the unit is in a city park (Balcones Community Park)
with a swimming pool. A substantial amount of the park is wooded and
undeveloped. There is dense commercial development in the southern and
southeastern portions of the unit. This unit contains Balcones District
Park Spring, which is occupied by the Jollyville Plateau salamander.
The spring is located in the streambed of an unnamed tributary to
Walnut Creek. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat.
Unit 33: Tributary 4 Unit
Unit 33 consists of 159 ac (64 ha) of private and City of Austin
land in northern Travis County, Texas. The unit is located west of the
intersection of Spicewood Springs Road and Old Lampasas Trail in the
Bull Creek Ranch community. The extreme western, northern, and eastern
portions of the unit are residential development. Undeveloped stream
corridors cross the unit from west to east. This unit contains three
spring sites: Tributary 4 upstream, Tributary 4 downstream, and
Spicewood Park Dam, which are occupied by the Jollyville Plateau
salamander. The springs are located on Tributary 4 and an unnamed
tributary to Bull Creek. The unit contains the primary constituent
elements essential for the conservation of the species.
[[Page 50819]]
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed, potential for vandalism, and depletion of groundwater (see
Special Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the springs, representing the extent of the subterranean
critical habitat. We joined the edges of the resulting circles.
Georgetown Salamander
Unit 1: Cobb Unit
Unit 1 consists of 83 ac (34 ha) of private land located in
northwestern Williamson County, Texas. The unit is undeveloped land.
This unit contains two springs, Cobb Springs and Cobb Well, both known
to be occupied by the Georgetown salamander. Cobb Springs is located on
Cobb Springs Branch, and Cobb Well is located on a tributary to the
stream. The unit contains the primary constituent elements essential
for the conservation of the species. Cobb Springs is a surface
location, and Cobb Well is a subterranean location for the species.
The unit requires special management because of the potential for
groundwater pollution from future development in the watershed and
depletion of groundwater (see Special Management Considerations or
Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat for Cobb
Springs. The unit was further delineated by drawing a circle with a
radius of 984 ft (300 m) around the spring and well, representing the
extent of the subterranean critical habitat. We joined the edges of the
resulting circles.
Unit 2: Cowen Creek Spring Unit
Unit 2 consists of 68 ac (28 ha) of private land located in west-
central Williamson County, Texas. The northern portion of the unit is
residential development; the remainder is undeveloped. This unit
contains Cowan Creek Spring, which is occupied by the Georgetown
salamander. The spring is located on Cowan Creek. The unit contains the
primary constituent elements essential for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 3: Bat Well Unit
Unit 3 consists of 68 ac (28 ha) of private land located in west-
central Williamson County, Texas. The western, northern, and southern
portion of the unit contains residential development. This unit
contains Bat Well, located in a cave and known to be occupied by the
Georgetown salamander. The cave is located in the Cowan Creek
watershed. The unit contains the primary constituent elements essential
for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the cave. The unit was further
delineated by drawing a circle with a radius of 984 ft (300 m) around
the cave, representing the extent of the subterranean critical habitat.
Unit 4: Walnut Spring Unit
Unit 4 consists of 68 ac (28 ha) of private and Williamson County
land located in west-central Williamson County, Texas. The western,
eastern, and northeastern portions of the unit contain low-density
residential development; the southern and north-central portions are
undeveloped. The extreme southeastern corner of the unit is part of
Williamson County Conservation Foundation's Twin Springs Preserve. This
unit contains Walnut Spring, which is occupied by the Georgetown
salamander. The spring is located on Walnut Spring Hollow. The unit
contains the primary constituent elements for the conservation of the
species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 5: Twin Springs Unit
Unit 5 consists of 68 ac (28 ha) of private and Williamson County
land located in west-central Williamson County, Texas. The northern
portion of the unit contains low-density residential development; the
remainder of the unit is undeveloped. The majority of the unit is part
of Williamson County Conservation Foundation's Twin Springs Preserve.
The preserve is managed by Williamson Conservation Foundation as a
mitigation property for the take of golden-cheeked warbler and Bone
Cave under the Williamson County Regional Habitat Conservation Plan.
The preserve habitat will be undeveloped in perpetuity. Salamander
populations are monitored, and there is some control of public access.
This unit contains Twin Springs, which is occupied by the Georgetown
salamander. The spring is located on Taylor Ray Hollow, a tributary of
Lake Georgetown. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 6: Hogg Hollow Spring Unit
Unit 6 consists of 68 ac (28 ha) of private and Federal undeveloped
land located in west-central Williamson County, Texas. Part of this
unit is on the U.S. Army Corps of Engineers Lake Georgetown's property.
There are currently no plans to develop the property. There is some
control of public access. This unit contains Hogg Hollow Spring, which
is occupied by the Georgetown salamander. The spring is located on Hogg
Hollow, a tributary to Lake Georgetown. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and
[[Page 50820]]
depletion of groundwater (see Special Management Considerations or
Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 7: Cedar Hollow Spring Unit
Unit 7 consists of 68 ac (28 ha) of private land in west-central
Williamson County, Texas. A secondary road crossed the extreme southern
portion of the unit, and there are residences in the northwestern,
southwestern, and west central portions of the unit. This unit contains
Cedar Hollow Spring, which is occupied by the Georgetown salamander.
The spring is located on Cedar Hollow, a tributary to Lake Georgetown.
The unit contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 8: Lake Georgetown Unit
Unit 8 consists of 132 ac (53 ha) of Federal and private land in
west-central Williamson County, Texas. Part of the unit is U.S. Army
Corps of Engineers Lake Georgetown property. There are currently no
plans to develop the property. There is some control of public access.
Unpaved roads are found in the western portion of the unit, and a trail
begins in the central part of the unit and leaves the northeast corner.
A secondary road crosses the extreme southern portion of the unit, and
there are residences in the northwestern, southwestern, and west
central portions of the unit. A large quarry is located a short
distance southeast of the unit. This unit two springs, Knight (Crockett
Gardens) Spring and Cedar Breaks Hiking Trail Spring, which are
occupied by the Georgetown salamander. The springs are located on an
unnamed tributary to Lake Georgetown. A portion of the northern part of
the unit extends under Lake Georgetown. The unit contains the primary
constituent elements essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed present operations and future expansion of the quarry, and
depletion of groundwater (see Special Management Considerations or
Protection section).
The proposed designation includes the spring outlets and outflows
up to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around each of the two springs, representing the extent of the
subterranean critical habitat. We joined the edges of the resulting
circles.
Unit 9: Water Tank Cave Unit
Unit 9 consists of 68 ac (28 ha) of private land in west-central
Williamson County, Texas. A golf course crosses the unit from northwest
to southeast, and there are several roads in the eastern part of the
unit. A secondary road crosses the extreme southern portion of the
unit, and there are residences in the northwestern, southwestern, and
west central portions of the unit. This unit contains Water Tank Cave,
a subterranean location, which is occupied by the Georgetown
salamander. The unit contains the primary constituent elements
essential for the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the subterranean cave. The unit
was further delineated by drawing a circle with a radius of 984 ft (300
m) around the cave, representing the extent of the subterranean
critical habitat.
Unit 10: Avant Spring Unit
Unit 10 consists of 68 ac (28 ha) of private land in west-central
Williamson County, Texas. The northern part of a large quarry is along
the southwestern edge of the unit. The rest of the unit is undeveloped.
This unit contains Avant's (Capitol Aggregates) Spring, which is
occupied by the Georgetown salamander. The spring is close to the
streambed of the Middle Fork of the San Gabriel River. The unit
contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlet and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 11: Buford Hollow Spring Unit
Unit 11 consists of 68 ac (28 ha) of Federal and private land in
west-central Williamson County, Texas. The unit is located just below
the spillway for Lake Georgetown. The U.S. Army Corps of Engineers owns
most of this unit as part of Lake Georgetown. The D.B. Wood Road, a
major thoroughfare, crosses the eastern part of the unit. The rest of
the unit is undeveloped. This unit contains Buford Hollow Springs,
which is occupied by the Georgetown salamander. The spring is located
on Buford Hollow, a tributary to the North Fork San Gabriel River. The
unit contains the primary constituent elements essential for the
conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 12: Swinbank Spring Unit
Unit 12 consists of 68 ac (28 ha) of City and private land in west-
central Williamson County, Texas. The unit is located near River Road
south of Melanie Lane. The northern part of the unit is primarily in
residential development, while the southern part of this unit is
primarily undeveloped. This unit contains Swinbank Spring, which is
occupied by the Georgetown salamander. The spring is located just off
the main channel of North Fork San Gabriel River. The unit contains the
primary constituent elements essential for the conservation of the
species. The population of Georgetown salamanders in the spring is
being monitored monthly as part of the Williamson
[[Page 50821]]
County Regional HCP's efforts to conserve the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section). Although the Georgetown
salamander has been given special consideration under the Williamson
County Regional HCP, take is not covered for this species (Williamson
County Conservation Foundation 2008, pp. 4-19). Actions authorized
under the HCP for the covered species may impact the Georgetown
salamander through habitat degradation (Williamson County Conservation
Foundation 2008, pp. 4-19). This includes increased impervious cover
and the associated decline in water quality.
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 13: Shadow Canyon Unit
Unit 13 consists of 68 ac (28 ha) of City and private land in west-
central Williamson County, Texas. The unit is located just south of
State Highway 29. This unit contains Shadow Canyon Spring, which is
occupied by the Georgetown salamander. The spring is located on an
unnamed tributary of South Fork San Gabriel River. The unit contains
the essential primary constituent elements for the conservation of the
species. The unit is authorized for development under the Shadow Canyon
HCP. Impacts to the endangered golden-cheeked warbler (Dendroica
chrysoparia) and Bone Cave harvestman (Texella reyesi) are permitted;
however, impacts to Georgetown salamander are not covered under the
HCP.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 14: San Gabriel Springs Unit
Unit 14 consists of 68 ac (28 ha) of City of Georgetown land in
west-central Williamson County, Texas. The unit is located between
North College Street and East Morrow Street, just north of the San
Gabriel River in San Gabriel Park. The northern part of the unit
contains some park buildings, parking lots, and other impervious
surfaces, but only the subterranean aquifer that extends below these
structures is included in the critical habitat unit. The southern part
of the unit is primarily undeveloped. This unit contains San Gabriel
Springs, which is occupied by the Georgetown salamander. Even though
the species has not been collected on the surface there since 1991
(Chippindale et al. 2000, p. 40; Pierce 2011b, pers. comm.), it may
occur on the subsurface. Therefore, we consider this unit to be
currently occupied. The spring is located just off the main channel of
the San Gabriel River, downstream of the confluence of the North San
Gabriel and South San Gabriel rivers. A city well is located
approximately 82 ft (25 m) from one of the spring outlets, and causes
the spring to go dry when it is active during the summer (TPWD 2011a,
p. 9). The unit contains the primary constituent elements essential for
the conservation of the species.
The unit requires special management because of the potential for
groundwater pollution from current and future development in the
watershed and depletion of groundwater from pumping (see Special
Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Salado Salamander
Unit 1: Hog Hollow Spring Unit
Unit 1 consists of 68 ac (28 ha) of private land located in
southwestern Bell County, Texas. The unit is primarily undeveloped
ranch land. This unit contains Hog Hollow Spring, which is occupied by
the Salado salamander. The unit is located on a tributary to Rumsey
Creek in the Salado Creek drainage and contains the primary constituent
elements essential for the conservation of the species. The owners of
the spring are interested in conserving the species, but there are
currently no long-term commitments to conservation in place.
The unit requires special management because of the potential for
groundwater pollution from future development in the watershed,
destruction of habitat by feral hogs, future depletion of groundwater,
and disturbance of habitat by livestock (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 2: Solana Spring 1 Unit
Unit 2 consists of 68 ac (28 ha) of private land located in
southwestern Bell County, Texas. The unit is primarily undeveloped
ranch land. This unit contains Solana Spring 1, which is
occupied by the Salado salamander. The unit is located on a tributary
to Rumsey Creek in the Salado Creek drainage and contains the primary
constituent elements essential for the conservation of the species. The
owners of the spring are interested in conserving the species, but
there are currently no long-term commitments to conservation in place.
The unit requires special management because of the potential for
groundwater pollution from future development in the watershed,
destruction of habitat by feral hogs, future depletion of groundwater,
and disturbance of habitat by livestock (see Special Management
Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 3: Cistern Spring Unit
Unit 3 consists of 68 ac (28 ha) of private land located in
southwestern Bell County, Texas, on the same private ranch as Units 1
and 2 for the Salado salamander. The unit is primarily undeveloped
ranch land. This unit contains Cistern Spring, which is occupied by the
Salado salamander. The unit is located on a tributary to Rumsey Creek
in the Salado Creek drainage and contains the primary constituent
elements essential for the conservation of the species. The owners of
the spring are interested in conserving the species, but there are
currently no long-term commitments to conservation in place.
The unit requires special management because of the potential for
groundwater
[[Page 50822]]
pollution from future development in the watershed, destruction of
habitat by feral hogs, future depletion of groundwater, and disturbance
of habitat by livestock (see Special Management Considerations or
Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around the spring, representing the extent of the subterranean
critical habitat.
Unit 4: IH-35 Unit
Unit 4 consists of 168 ac (68 ha) of private, State, and City of
Salado land located in southwestern Bell County, Texas, in the southern
part of the Village of Salado. The unit extends along Salado Creek on
both sides of Interstate Highway 35 (IH 35). The IH 35 right of way
crosses Salado Creek and is owned by the Texas Department of
Transportation. The unit is a mixture of residential and commercial
properties on its eastern portion, with some undeveloped ranch land in
the western part west of IH 35. This unit contains four springs, all
located on private property: Robertson Spring, Big Boiling Spring, Lil'
Bubbly Spring, and Lazy Days Fish Farm, all known to be occupied by the
Salado salamander.
There has been some recent modification to the spring habitat
within this unit. In the fall of 2011, the outflow channels and edges
of Big Boiling and Lil' Bubbly Spring were reconstructed with large
limestone blocks and mortar. In addition, in response to other activity
in the area, the U.S. Army Corps of Engineers issued a cease and desist
order to the Salado Chamber of Commerce in October 2011, for
unauthorized discharge of dredged or fill material that occurred in
this area (Brooks 2011, U.S. Corps of Engineers, pers. comm.). This
order was issued in relation to the need for a section 404 permit under
the Clean Water Act. A citation from a TPWD game warden was also issued
in October 2011, due to the need for a sand and gravel permit from the
TPWD for work being conducted within TPWD jurisdiction (Heger 2012a,
pers. comm.). The citation was issued because the Salado Chamber of
Commerce had been directed by the game warden to stop work within
TPWD's jurisdiction, which the Salado Chamber of Commerce did
temporarily, but work started again in spite of the game warden's
directive (Heger 2012a, pers. comm.). A sand and gravel permit was
obtained on March 21, 2012. The spring run modifications were already
completed by this date, but further modifications in the springs were
prohibited by the permit. Additional work on the bank upstream of the
springs was permitted and completed (Heger 2012b, pers. comm.).
The unit requires special management to protect it from illegal
dumping within the stream channel, surface runoff from nearby roads and
other development, the potential for groundwater pollution from future
development in the watershed, future depletion of groundwater, and
habitat disturbance from livestock and feral hogs (see Special
Management Considerations or Protection section).
The proposed designation includes the spring outlets and outflow up
to the high water line and 164 ft (50 m) of downstream habitat. The
unit was further delineated by drawing a circle with a radius of 984 ft
(300 m) around each of the four springs, representing the extent of the
subterranean critical habitat. We then joined the edges of the
resulting circles.
Effects of Critical Habitat Designation
Section 7 Consultation
Section 7(a)(2) of the Act requires Federal agencies, including the
Service, to ensure that any action they fund, authorize, or carry out
is not likely to jeopardize the continued existence of any endangered
species or threatened species or result in the destruction or adverse
modification of designated critical habitat of such species. In
addition, section 7(a)(4) of the Act requires Federal agencies to
confer with the Service on any agency action which is likely to
jeopardize the continued existence of any species proposed to be listed
under the Act or result in the destruction or adverse modification of
proposed critical habitat.
Decisions by the 5th and 9th Circuit Courts of Appeals have
invalidated our regulatory definition of ``destruction or adverse
modification'' (50 CFR 402.02) (see Gifford Pinchot Task Force v. U.S.
Fish and Wildlife Service, 378 F. 3d 1059 (9th Cir. 2004) and Sierra
Club v. U.S. Fish and Wildlife Service et al., 245 F.3d 434, 442 (5th
Cir. 2001)), and we do not rely on this regulatory definition when
analyzing whether an action is likely to destroy or adversely modify
critical habitat. Under the statutory provisions of the Act, we
determine destruction or adverse modification on the basis of whether,
with implementation of the proposed Federal action, the affected
critical habitat would continue to serve its intended conservation role
for the species.
If a Federal action may affect a listed species or its critical
habitat, the responsible Federal agency (action agency) must enter into
consultation with us. Examples of actions that are subject to the
section 7 consultation process are actions on State, tribal, local, or
private lands that require a Federal permit (such as a permit from the
U.S. Army Corps of Engineers under section 404 of the Clean Water Act
(33 U.S.C. 1251 et seq.) or a permit from the Service under section 10
of the Act) or that involve some other Federal action (such as funding
from the Federal Highway Administration, Federal Aviation
Administration, or the Federal Emergency Management Agency). Federal
actions not affecting listed species or critical habitat, and actions
on State, tribal, local, or private lands that are not federally funded
or authorized, do not require section 7 consultation.
As a result of section 7 consultation, we document compliance with
the requirements of section 7(a)(2) through our issuance of:
(1) A concurrence letter for Federal actions that may affect, but
are not likely to adversely affect, listed species or critical habitat;
or
(2) A biological opinion for Federal actions that may affect, or
are likely to adversely affect, listed species or critical habitat.
When we issue a biological opinion concluding that a project is
likely to jeopardize the continued existence of a listed species and
destroy or adversely modify critical habitat, we provide reasonable and
prudent alternatives to the project, if any are identifiable, that
would avoid the likelihood of jeopardy and destruction or adverse
modification of critical habitat. We define ``reasonable and prudent
alternatives'' (at 50 CFR 402.02) as alternative actions identified
during consultation that:
(1) Can be implemented in a manner consistent with the intended
purpose of the action,
(2) Can be implemented consistent with the scope of the Federal
agency's legal authority and jurisdiction,
(3) Are economically and technologically feasible, and
(4) Would, in the Director's opinion, avoid the likelihood of
jeopardizing the continued existence of the listed species and avoid
the likelihood of destroying or adversely modifying critical habitat.
Reasonable and prudent alternatives can vary from slight project
modifications to extensive redesign or relocation of the project. Costs
associated with implementing a reasonable and prudent alternative are
similarly variable.
Regulations at 50 CFR 402.16 require Federal agencies to reinitiate
[[Page 50823]]
consultation on previously reviewed actions in instances where we have
listed a new species or subsequently designated critical habitat that
may be affected and the Federal agency has retained discretionary
involvement or control over the action (or the agency's discretionary
involvement or control is authorized by law). Consequently, Federal
agencies sometimes may need to request reinitiation of consultation
with us on actions for which formal consultation has been completed, if
those actions with discretionary involvement or control may affect
subsequently listed species or designated critical habitat.
Application of the ``Adverse Modification'' Standard
The key factor related to the adverse modification determination is
whether, with implementation of the proposed Federal action, the
affected critical habitat would continue to serve its intended
conservation role for the species. Activities that may destroy or
adversely modify critical habitat are those that alter the physical or
biological features to an extent that appreciably reduces the
conservation value of critical habitat for the four salamander species.
As discussed above, the role of critical habitat is to support life-
history needs of the species and provide for the conservation of the
species.
Section 4(b)(8) of the Act requires us to briefly evaluate and
describe, in any proposed or final regulation that designates critical
habitat, activities involving a Federal action that may destroy or
adversely modify such habitat, or that may be affected by such
designation.
Activities that may affect critical habitat, when carried out,
funded, or authorized by a Federal agency, should result in
consultation for the four salamander species. These activities include,
but are not limited to:
(1) Actions that would physically disturb the spring habitat upon
which these four Texas salamander species depend. Such activities could
include, but are not limited to, channelization and other activities
that result in the physical destruction of habitat or the modification
of habitat so that it is not suitable for the species.
(2) Actions that would increase the concentration of silt in the
surface or subsurface habitat. Such activities could include, but are
not limited to, increases in impervious cover in the surface watershed,
improper erosion controls on the surface and subsurface watersheds,
release of pollutants into the surface water or connected groundwater
at a point source or by dispersed release (non-point source). These
activities could alter water conditions to levels that are beyond the
tolerances of the four Texas salamander species and result in direct or
cumulative adverse effects to these individuals and their life cycles.
(3) Actions that would deplete the aquifer to an extent that
decreases or stops the flow of occupied springs or that reduce the
quantity of subterranean habitat used by the species. Such activities
could include, but are not limited to, excessive water withdrawals from
aquifers and channelization or other modification of recharge features
that would decrease recharge. These activities could dewater habitat or
cause reduced water quality to levels that are beyond the tolerances of
the four Texas salamanders and result in direct or cumulative adverse
effects to these individuals and their life cycles.
Exemptions
Application of Section 4(a)(3) of the Act
The Sikes Act Improvement Act of 1997 (Sikes Act) (16 U.S.C. 670a)
required each military installation that includes land and water
suitable for the conservation and management of natural resources to
complete an integrated natural resources management plan (INRMP) by
November 17, 2001. An INRMP integrates implementation of the military
mission of the installation with stewardship of the natural resources
found on the base. Each INRMP includes:
(1) An assessment of the ecological needs on the installation,
including the need to provide for the conservation of listed species;
(2) A statement of goals and priorities;
(3) A detailed description of management actions to be implemented
to provide for these ecological needs; and
(4) A monitoring and adaptive management plan.
Among other things, each INRMP must, to the extent appropriate and
applicable, provide for fish and wildlife management; fish and wildlife
habitat enhancement or modification; wetland protection, enhancement,
and restoration where necessary to support fish and wildlife; and
enforcement of applicable natural resource laws.
The National Defense Authorization Act for Fiscal Year 2004 (Pub.
L. 108-136) amended the Act to limit areas eligible for designation as
critical habitat. Specifically, section 4(a)(3)(B)(i) of the Act (16
U.S.C. 1533(a)(3)(B)(i)) now provides: ``The Secretary shall not
designate as critical habitat any lands or other geographic areas owned
or controlled by the Department of Defense, or designated for its use,
that are subject to an integrated natural resources management plan
prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if the
Secretary determines in writing that such plan provides a benefit to
the species for which critical habitat is proposed for designation.''
There are no Department of Defense lands within the proposed
critical habitat designation.
Exclusions
Application of Section 4(b)(2) of the Act
Section 4(b)(2) of the Act states that the Secretary shall
designate and make revisions to critical habitat on the basis of the
best available scientific data after taking into consideration the
economic impact, national security impact, and any other relevant
impact of specifying any particular area as critical habitat. The
Secretary may exclude an area from critical habitat if he determines
that the benefits of such exclusion outweigh the benefits of specifying
such area as part of the critical habitat, unless he determines, based
on the best scientific data available, that the failure to designate
such area as critical habitat will result in the extinction of the
species. In making that determination, the statute on its face, as well
as the legislative history are clear that the Secretary has broad
discretion regarding which factor(s) to use and how much weight to give
to any factor.
In considering whether to exclude a particular area from the
designation, we identify the benefits of including the area in the
designation, identify the benefits of excluding the area from the
designation, and evaluate whether the benefits of exclusion outweigh
the benefits of inclusion. If the analysis indicates that the benefits
of exclusion outweigh the benefits of inclusion, the Secretary may
exercise his discretion to exclude the area only if such exclusion
would not result in the extinction of the species.
When identifying the benefits of inclusion for an area, we consider
the additional regulatory benefits that area would receive from the
protection from adverse modification or destruction as a result of
actions with a Federal nexus; the educational benefits of mapping
essential habitat for recovery of the listed species; and any benefits
that may result from a designation due to State or Federal laws that
may apply to critical habitat.
When identifying the benefits of exclusion, we consider, among
other
[[Page 50824]]
things, whether exclusion of a specific area is likely to result in
conservation; the continuation, strengthening, or encouragement of
partnerships; or implementation of a management plan that provides
equal to or more conservation than a critical habitat designation would
provide.
In the case of the four central Texas salamanders, the benefits of
critical habitat include public awareness of Austin blind salamander,
Georgetown salamander, Jollyville Plateau salamander, and Salado
salamander presence and the importance of habitat protection, and in
cases where a Federal nexus exists, increased habitat protection for
Austin blind salamander, Georgetown salamander, Jollyville Plateau
salamander, and Salado salamander due to the protection from adverse
modification or destruction of critical habitat.
When we evaluate the existence of a conservation plan when
considering the benefits of exclusion, we consider a variety of
factors, including but not limited to, whether the plan is finalized;
how it provides for the conservation of the essential physical or
biological features; whether there is a reasonable expectation that the
conservation management strategies and actions contained in a
management plan will be implemented into the future; whether the
conservation strategies in the plan are likely to be effective; and
whether the plan contains a monitoring program or adaptive management
to ensure that the conservation measures are effective and can be
adapted in the future in response to new information.
After identifying the benefits of inclusion and the benefits of
exclusion, we carefully weigh the two sides to evaluate whether the
benefits of exclusion outweigh those of inclusion. If our analysis
indicates that the benefits of exclusion outweigh the benefits of
inclusion, we then determine whether exclusion would result in
extinction. If exclusion of an area from critical habitat will result
in extinction, we will not exclude it from the designation.
Based on the information that will be provided by entities seeking
exclusion, as well as any additional public comments we receive during
the open public comment period (see DATES), we will evaluate whether
certain lands in the proposed critical habitat for Jollyville Plateau
salamander in the Bull Creek 3 Unit (Unit 19 for the Jollyville Plateau
salamander) are appropriate for exclusion from the final designation
under section 4(b)(2) of the Act. If the analysis indicates that the
benefits of excluding lands from the final designation outweigh the
benefits of designating those lands as critical habitat, then the
Secretary may exercise his discretion to exclude the lands from the
final designation.
After considering the following areas under section 4(b)(2) of the
Act, we are proposing to exclude them from the critical habitat
designation for Jollyville Plateau salamander.
Table 11--Areas Considered for Exclusion by Critical Habitat Unit for the Jollyville Plateau Salamander
----------------------------------------------------------------------------------------------------------------
Areas meeting the
definition of critical Areas considered for
Unit Specific area habitat, in acres possible exclusion, in
(hectares) acres (hectares)
----------------------------------------------------------------------------------------------------------------
Unit 19: Bull Creek 3 Unit........ Four Points HCP...... 254 ac (103 ha) 152 ac (62 ha).
----------------------------------------------------------------------------------------------------------------
We are considering these areas for exclusion, because we believe
that:
(1) Their value for conservation will be preserved for the
foreseeable future by existing protective actions, or
(2) They are appropriate for exclusion under the ``other relevant
factor'' provisions of section 4(b)(2) of the Act.
However, we specifically solicit comments on the inclusion or
exclusion of such areas. In the paragraphs below, we provide a detailed
analysis of our exclusion of these lands under section 4(b)(2) of the
Act.
Exclusions Based on Economic Impacts
Under section 4(b)(2) of the Act, we consider the economic impacts
of specifying any particular area as critical habitat. In order to
consider economic impacts, we are preparing an analysis of the economic
impacts of the proposed critical habitat designation and related
factors.
Sectors that may be affected by the proposed designation include
private developers of residential and commercial property; city,
county, and State governments that construct and maintain roads and
other infrastructure; and entities that pump water from the aquifers.
We will announce the availability of the draft economic analysis as
soon as it is completed, at which time we will seek public review and
comment. At that time, copies of the draft economic analysis will be
available for downloading from the Internet at http://www.regulations.gov, or by contacting the Austin Ecological Services
Field Office directly (see FOR FURTHER INFORMATION CONTACT). During the
development of a final designation, we will consider economic impacts,
public comments, and other new information, and areas may be excluded
from the final critical habitat designation under section 4(b)(2) of
the Act and our implementing regulations at 50 CFR 424.19.
Exclusions Based on National Security Impacts
Under section 4(b)(2) of the Act, we consider whether there are
lands owned or managed by the Department of Defense (DOD) where a
national security impact might exist. In preparing this proposal, we
have determined that the lands within the proposed designation of
critical habitat for Austin blind salamander, Georgetown salamander,
Jollyville Plateau salamander, and Salado salamander are not owned or
managed by the Department of Defense, and, therefore, we anticipate no
impact on national security. Consequently, the Secretary does not
propose to exercise his discretion to exclude any areas from the final
designation based on impacts on national security.
Exclusions Based on Other Relevant Impacts
Under section 4(b)(2) of the Act, we consider any other relevant
impacts, in addition to economic impacts and impacts on national
security. We consider a number of factors including whether the
landowners have developed any HCPs or other management plans for the
area, or whether there are conservation partnerships that would be
encouraged by designation of, or exclusion from, critical habitat. In
addition, we look at any tribal issues, and consider the government-to-
government relationship of the United States with tribal entities. We
also
[[Page 50825]]
consider any social impacts that might occur because of the
designation.
Land and Resource Management Plans, Conservation Plans, or Agreements
Based on Conservation Partnerships
We consider a current land management or conservation plan (HCPs as
well as other types) to provide adequate management or protection if it
meets the following criteria:
(1) The plan is complete and provides the same or better level of
protection from adverse modification or destruction than that provided
through a consultation under section 7 of the Act;
(2) There is a reasonable expectation that the conservation
management strategies and actions will be implemented for the
foreseeable future, based on past practices, written guidance, or
regulations; and
(3) The plan provides conservation strategies and measures
consistent with currently accepted principles of conservation biology.
We believe that the Four Points HCP fulfills the above criteria,
and are considering the exclusion of non-Federal lands covered by this
plan that provide for the conservation of Jollyville Plateau
salamander. We are requesting comments on the benefit to Jollyville
Plateau salamander from this HCP.
Four Points Habitat Conservation Plan
The Permittee (TPG Four Points Land, L.P.) is authorized to
``take'' (kill, harm, or harass) the golden-cheeked warbler, black-
capped vireo, Tooth Cave ground beetle, Bone Cave harvestman, Bee Creek
Cave harvestman, Tooth Cave pseudoscorpion (Tartarocreagris texana),
Tooth Cave spider (Tayshaneta myopica), Kretschmarr Cave mold beetle
(Texamaurops reddelli), and the Coffin Cave mold beetle (Batrisodes
texanus) at a known location (the 333-ac (135-ha) Four Points Property,
located approximately 11 mi (18 km) northwest of Austin near the
intersection of RM 2222 and RM 620, Travis County, Texas), of habitat
for these species, incidental to activities necessary for the
construction of mixed use real estate development projects and
attendant utilities as described in the original Permittee's (P-WB
Joint Venture) application and habitat conservation plan. The HCP also
covers the Jollyville Plateau salamander as if it were a listed
species, meaning that impacts to this salamander species from
construction activites described in the permit are permitted.
The HCP requires avoidance of direct impacts to warblers by not
conducting clearing or construction in occupied golden-cheeked warbler
habitat and by initiating clearing and construction only during times
of year when birds are not present. Approximately 52 ac (21 ha) that
contains six caves (Owl Eyes, Japygid, Eluvial, Fernpit, M.W.A., and
Jollyville) known to be inhabited by Tooth Cave ground beetle and the
Bone Cave harvestman have been permanently preserved.
Protection of this area is also expected to contribute to the
maintenance of water quality, and, therefore, the quality of salamander
habitat at resurgence springs (Spring No. 12, Spring No. 22, and Spring
No. 24) down-gradient of the preserve area. In addition, runoff from
multi-family residential areas and the hotel will be routed to avoid
drainages which contain springs known to support Jollyville Plateau
salamanders.
In addition to the karst preserve, another approximately 135 ac (54
ha) of the property was permanently set aside and maintained as a
golden-cheeked warbler preserve.
All preserve areas will be permanently fenced and posted to
preclude public access, and red imported fire ants (Solenopsis invicta)
will be controlled in the karst preserves. Fire ants are a pervasive,
nonnative ant species originally introduced to the United States from
South America over 50 years ago and are an aggressive predator and
competitor that has spread across the southern United States. They
often replace native species, and evidence shows that overall arthropod
diversity, as well as species richness and abundance, decreases in
infested areas. Fire ants are spread by activities that accompany
urbanization and that result in soil disturbance and disruption to
native ant communities. As such, fire ants will be controlled by
limiting these types of activities. No pesticides or herbicides will be
used within preserve areas, and any pesticides or herbicides used
within developed areas will be used according to the EPA label
instructions.
Peer Review
In accordance with our joint policy on peer review published in the
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert
opinions of at least three appropriate and independent specialists
regarding this proposed rule. The purpose of peer review is to ensure
that our listing determination and critical habitat designation are
based on scientifically sound data, assumptions, and analyses. We have
invited these peer reviewers to comment during this public comment
period on our specific assumptions and conclusions in this proposed
listing and designation of critical habitat.
We will consider all comments and information we receive during
this comment period on this proposed rule during our preparation of a
final determination. Accordingly, the final decision may differ from
this proposal.
Public Hearings
Section 4(b)(5) of the Act provides for one or more public hearings
on this proposal, if requested. Requests must be received within 45
days after the date of publication of this proposed rule in the Federal
Register. Such requests must be sent to the address shown in the FOR
FURTHER INFORMATION CONTACT section. We will schedule public hearings
on this proposal, if any are requested, and announce the dates, times,
and places of those hearings, as well as how to obtain reasonable
accommodations, in the Federal Register and local newspapers at least
15 days before the hearing.
Required Determinations
Regulatory Planning and Review--Executive Order 12866
Executive Order 12866 provides that the Office of Information and
Regulatory Affairs (OIRA) will review all significant rules. The Office
of Information and Regulatory Affairs has determined that this rule is
not significant.
Executive Order 13563 reaffirms the principles of E.O. 12866 while
calling for inprovements in the nation's regulatory system to promote
predictability, to reduce uncertainty, and to use the best, most
innovative, and least burdensome tools for achieving regulatory ends.
The executive order directs agencies to consider regulatory approaches
that reduce burdens and maintain flexibility and freedom of choice for
the public where these approaches are relevant, feasible, and
consistent with regulatory objectives. E.O. 13563 emphasizes further
that regulations must be based on the best available science and that
the rulemaking process must allow for public participation and an open
exchange of ideas. We have developed this rule in a manner consistent
with these requirements.
Regulatory Flexibility Act (5 U.S.C. 601 et seq.)
Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.) as
amended by the Small Business Regulatory Enforcement Fairness Act of
1996 (SBREFA; 5 U.S.C. 801 et seq.), whenever an agency is required to
publish a notice of rulemaking for any proposed or final rule, it must
prepare
[[Page 50826]]
and make available for public comment a regulatory flexibility analysis
that describes the effects of the rule on small entities (small
businesses, small organizations, and small government jurisdictions).
However, no regulatory flexibility analysis is required if the head of
the agency certifies the rule will not have a significant economic
impact on a substantial number of small entities. The SBREFA amended
the RFA to require Federal agencies to provide a certification
statement of the factual basis for certifying that the rule will not
have a significant economic impact on a substantial number of small
entities.
According to the Small Business Administration, small entities
include small organizations such as independent nonprofit
organizations; small governmental jurisdictions, including school
boards and city and town governments that serve fewer than 50,000
residents; and small businesses (13 CFR 121.201). Small businesses
include such businesses as manufacturing and mining concerns with fewer
than 500 employees, wholesale trade entities with fewer than 100
employees, retail and service businesses with less than $5 million in
annual sales, general and heavy construction businesses with less than
$27.5 million in annual business, special trade contractors doing less
than $11.5 million in annual business, and forestry and logging
operations with fewer than 500 employees and annual business less than
$7 million. To determine whether small entities may be affected, we
will consider the types of activities that might trigger regulatory
impacts under this designation as well as types of project
modifications that may result. In general, the term ``significant
economic impact'' is meant to apply to a typical small business firm's
business operations.
Importantly, the incremental impacts of a rule must be both
significant and substantial to prevent certification of the rule under
the RFA and to require the preparation of an initial regulatory
flexibility analysis. If a substantial number of small entities are
affected by the proposed critical habitat designation, but the per-
entity economic impact is not significant, the Service may certify.
Likewise, if the per-entity economic impact is likely to be
significant, but the number of affected entities is not substantial,
the Service may also certify.
Under the RFA, as amended, and following recent court decisions,
Federal agencies are only required to evaluate the potential
incremental impacts of rulemaking on those entities directly regulated
by the rulemaking itself, and not the potential impacts to indirectly
affected entities. The regulatory mechanism through which critical
habitat protections are realized is section 7 of the Act, which
requires Federal agencies, in consultation with the Service, to ensure
that any action authorized, funded, or carried by the Agency is not
likely to adversely modify critical habitat. Therefore, only Federal
action agencies are directly subject to the specific regulatory
requirement (avoiding destruction and adverse modification) imposed by
critical habitat designation. Under these circumstances, it is our
position that only Federal action agencies will be directly regulated
by this designation. Therefore, because Federal agencies are not small
entities, the Service may certify that the proposed critical habitat
rule will not have a significant economic impact on a substantial
number of small entities.
We acknowledge, however, that in some cases, third-party proponents
of the action subject to permitting or funding may participate in a
section 7 consultation, and thus may be indirectly affected. We believe
it is good policy to assess these impacts if we have sufficient data
before us to complete the necessary analysis, whether or not this
analysis is strictly required by the RFA. While this regulation does
not directly regulate these entities, in our draft economic analysis we
will conduct a brief evaluation of the potential number of third
parties participating in consultations on an annual basis in order to
ensure a more complete examination of the incremental effects of this
proposed rule in the context of the RFA.
In conclusion, we believe that, based on our interpretation of
directly regulated entities under the RFA and relevant case law, this
designation of critical habitat will only directly regulate Federal
agencies which are not by definition small business entities. And as
such, certify that, if promulgated, this designation of critical
habitat would not have a significant economic impact on a substantial
number of small business entities. Therefore, an initial regulatory
flexibility analysis is not required. However, though not necessarily
required by the RFA, in our draft economic analysis for this proposal
we will consider and evaluate the potential effects to third parties
that may be involved with consultations with Federal action agencies
related to this action.
Energy Supply, Distribution, or Use--Executive Order 13211
Executive Order 13211 (Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use) requires
agencies to prepare Statements of Energy Effects when undertaking
certain actions.
We do not expect the designation of this proposed critical habitat
to significantly affect energy supplies, distribution, or use, because
the majority of the lands we are proposing as critical habitat are
privately owned, and do not have energy production or distribution.
Therefore, this action is not a significant energy action, and no
Statement of Energy Effects is required. However, we will further
evaluate this issue as we conduct our economic analysis, and review and
revise this assessment as warranted.
Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)
In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501
et seq.), we make the following findings:
(1) This rule would not produce a Federal mandate. In general, a
Federal mandate is a provision in legislation, statute, or regulation
that would impose an enforceable duty upon State, local, or tribal
governments, or the private sector, and includes both ``Federal
intergovernmental mandates'' and ``Federal private sector mandates.''
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal
intergovernmental mandate'' includes a regulation that ``would impose
an enforceable duty upon State, local, or tribal governments'' with two
exceptions. It excludes ``a condition of Federal assistance.'' It also
excludes ``a duty arising from participation in a voluntary Federal
program,'' unless the regulation ``relates to a then-existing Federal
program under which $500,000,000 or more is provided annually to State,
local, and tribal governments under entitlement authority,'' if the
provision would ``increase the stringency of conditions of assistance''
or ``place caps upon, or otherwise decrease, the Federal Government's
responsibility to provide funding,'' and the State, local, or tribal
governments ``lack authority'' to adjust accordingly. At the time of
enactment, these entitlement programs were: Medicaid; Aid to Families
with Dependent Children work programs; Child Nutrition; Food Stamps;
Social Services Block Grants; Vocational Rehabilitation State Grants;
Foster Care, Adoption Assistance, and Independent Living; Family
Support Welfare Services; and Child Support
[[Page 50827]]
Enforcement. ``Federal private sector mandate'' includes a regulation
that ``would impose an enforceable duty upon the private sector, except
(i) a condition of Federal assistance or (ii) a duty arising from
participation in a voluntary Federal program.''
The designation of critical habitat does not impose a legally
binding duty on non-Federal Government entities or private parties.
Under the Act, the only regulatory effect is that Federal agencies must
ensure that their actions do not destroy or adversely modify critical
habitat under section 7. While non-Federal entities that receive
Federal funding, assistance, or permits, or that otherwise require
approval or authorization from a Federal agency for an action, may be
indirectly impacted by the designation of critical habitat, the legally
binding duty to avoid destruction or adverse modification of critical
habitat rests squarely on the Federal agency. Furthermore, to the
extent that non-Federal entities are indirectly impacted because they
receive Federal assistance or participate in a voluntary Federal aid
program, the Unfunded Mandates Reform Act would not apply, nor would
critical habitat shift the costs of the large entitlement programs
listed above onto State governments.
(2) We do not believe that this rule would significantly or
uniquely affect small governments because the proposed areas that cover
small government jurisdictions are small, and there is little potential
that the proposal would impose significant additional costs above those
associated with the proposed listing of the species. Therefore, a Small
Government Agency Plan is not required. However, we will further
evaluate this issue as we conduct our economic analysis, and review and
revise this assessment if appropriate.
Takings--Executive Order 12630
In accordance with Executive Order 12630 (Government Actions and
Interference with Constitutionally Protected Private Property Rights),
we will analyze the potential takings implications of designating
critical habitat for the Austin blind salamander, Georgetown
salamander, Jollyville Plateau salamander, and Salado salamander in a
takings implications assessment. Following publication of this proposed
rule, a draft economic analysis will be completed for the proposed
designation. The draft economic analysis will provide the foundation
for us to use in preparing a takings implications assessment.
Federalism--Executive Order 13132
In accordance with Executive Order 13132 (Federalism), this
proposed rule does not have significant Federalism effects. A
Federalism assessment is not required. In keeping with Department of
the Interior and Department of Commerce policy, we requested
information from, and coordinated development of, this proposed
critical habitat designation with appropriate State resource agencies
in Texas. The designation of critical habitat in areas currently
occupied by the Austin blind salamander, Georgetown salamander,
Jollyville Plateau salamander, and Salado salamander may impose nominal
additional regulatory restrictions to those currently in place and,
therefore, may have little incremental impact on State and local
governments and their activities. The designation may have some benefit
to these governments because the areas that contain the physical or
biological features essential to the conservation of the species are
more clearly defined, and the elements of the features of the habitat
necessary to the conservation of the species are specifically
identified. This information does not alter where and what federally
sponsored activities may occur. However, it may assist local
governments in long-range planning (rather than having them wait for
case-by-case section 7 consultations to occur).
Where State and local governments require approval or authorization
from a Federal agency for actions that may affect critical habitat,
consultation under section 7(a)(2) would be required. While non-Federal
entities that receive Federal funding, assistance, or permits, or that
otherwise require approval or authorization from a Federal agency for
an action may be indirectly impacted by the designation of critical
habitat, the legally binding duty to avoid destruction or adverse
modification of critical habitat rests squarely on the Federal agency.
Civil Justice Reform--Executive Order 12988
In accordance with Executive Order 12988 (Civil Justice Reform),
the Office of the Solicitor has determined that the rule does not
unduly burden the judicial system and that it meets the requirements of
sections 3(a) and 3(b)(2) of the Order. We have proposed designating
critical habitat in accordance with the provisions of the Act. This
proposed rule uses standard property descriptions and identifies the
elements of physical or biological features essential to the
conservation of the Austin blind salamander, Georgetown salamander,
Jollyville Plateau salamander, and Salado salamander within the
designated areas to assist the public in understanding the habitat
needs of the species.
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)
This rule does not contain any new collections of information that
require approval by the Office of Management and Budget under the
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). This rule
will not impose recordkeeping or reporting requirements on State or
local governments, individuals, businesses, or organizations. An agency
may not conduct or sponsor, and a person is not required to respond to,
a collection of information unless it displays a currently valid OMB
control number.
National Environmental Policy Act (42 U.S.C. 4321 et seq.)
It is our position that, outside the jurisdiction of the U.S. Court
of Appeals for the Tenth Circuit, we do not need to prepare
environmental analyses pursuant to the National Environmental Policy
Act (NEPA; 42 U.S.C. 4321 et seq.) in connection with designating
critical habitat under the Act. We published a notice outlining our
reasons for this determination in the Federal Register on October 25,
1983 (48 FR 49244). This position was upheld by the U.S. Court of
Appeals for the Ninth Circuit (Douglas County v. Babbitt, 48 F.3d 1495
(9th Cir. 1995), cert. denied 516 U.S. 1042 (1996)). The proposed
designation of critical habitat for the four Texas salamanders is
entirely within the 5th Circuit jurisdiction; therefore, we do not
intend to prepare an environmental analysis in connection with this
proposed critical habitat designation.
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in the ADDRESSES
[[Page 50828]]
section. To better help us revise the rule, your comments should be as
specific as possible. For example, you should tell us the numbers of
the sections or paragraphs that are unclearly written, which sections
or sentences are too long, the sections where you feel lists or tables
would be useful, etc.
Government-to-Government Relationship With Tribes
In accordance with the President's memorandum of April 29, 1994
(Government-to-Government Relations with Native American Tribal
Governments; 59 FR 22951), Executive Order 13175 (Consultation and
Coordination With Indian Tribal Governments), and the Department of the
Interior's manual at 512 DM 2, we readily acknowledge our
responsibility to communicate meaningfully with recognized Federal
Tribes on a government-to-government basis. In accordance with
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights,
Federal-Tribal Trust Responsibilities, and the Endangered Species Act),
we readily acknowledge our responsibilities to work directly with
tribes in developing programs for healthy ecosystems, to acknowledge
that tribal lands are not subject to the same controls as Federal
public lands, to remain sensitive to Indian culture, and to make
information available to tribes.
We determined that there are no Tribal lands that are occupied by
the four central Texas salamanders. Therefore, we are not proposing to
designate critical habitat for the salamander species on Tribal lands.
References Cited
A complete list of references cited in this rulemaking is available
on the Internet at http://www.regulations.gov and upon request from the
Austin Ecological Services Field Office (see FOR FURTHER INFORMATION
CONTACT).
Authors
The primary authors of this package are the staff members of the
Austin Ecological Services Field Office, Arlington Ecological Services
Field Office, and the Texas Fish and Wildlife Conservation Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
2. Amend Sec. 17.11(h) by adding entries for ``Salamander, Austin
blind'', ``Salamander, Georgetown'', ``Salamander, Jollyville
Plateau'', and ``Salamander, Salado'' in alphabetical order under
AMPHIBIANS to the List of Endangered and Threatened Wildlife to read as
follows:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
-------------------------------------------------------- population where When Critical Special
Historic range endangered or Status listed habitat rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
Amphibians
* * * * * * *
Salamander, Austin blind......... Eurycea U.S.A. (TX)........ Entire............. E ........... 17.95(d) NA
waterlooensis.
* * * * * * *
Salamander, Georgetown........... Eurycea naufragia... U.S.A. (TX)........ Entire............. E ........... 17.95(d) NA
Salamander, Jollyville Plateau... Eurycea tonkawae.... U.S.A. (TX)........ Entire............. E ........... 17.95(d) NA
* * * * * * *
Salamander, Salado............... Eurycea U.S.A. (TX)........ Entire............. E ........... 17.95(d) NA
chisholmensis.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
3. Amend Sec. 17.95(d) by adding entries for ``Austin Blind
Salamander (Eurycea waterlooensis),'' ``Georgetown Salamander (Eurycea
naufragia)'', ``Jollyville Plateau Salamander (Eurycea tonkawae)'', and
``Salado Salamander (Eurycea chisholmensis)'', in the same alphabetical
order in which the species appear in the table at Sec. 17.11(h), to
read as follows:
Sec. 17.95 Critical habitat--fish and wildlife.
* * * * *
(d) Amphibians.
* * * * *
Austin Blind Salamander (Eurycea waterlooensis)
(1) The critical habitat unit is depicted for Travis County, Texas,
on the map below.
(2) Within this area, the primary constituent elements of the
physical or biological features essential to the conservation of Austin
blind salamander consist of four components:
(i) Water from the Barton Springs Segment of the Edwards Aquifer.
The groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander are below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Austin blind salamander prey base). Hydrologic
[[Page 50829]]
regimes similar to the historical pattern of the specific sites are
present, with at least temporal surface flow for spring sites and
continuous flow for subterranean sites. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 67.8
and 72.3 [deg]F (19.9 and 22.4 [deg]C), dissolved oxygen concentrations
between 5 and 7 milligrams per liter, and specific water conductance
between 605 and 740 microsiemens per centimeter.
(ii) Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat must be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
should have minimal sedimentation.
(iii) Aquatic invertebrates for food. The spring and cave
environments must be capable of supporting a diverse aquatic
invertebrate community that includes crustaceans and insects.
(iv) Subterranean aquifer. During periods of drought or dewatering
on the surface in and around spring sites, access to the subsurface
water table must be provided for shelter and protection.
(3) Surface critical habitat includes the spring outlets and
outflow up to the high water line and 164 ft (50 m) of downstream
habitat, but does not include manmade structures (such as buildings,
aqueducts, runways, roads, and other paved areas) and the land on which
they are located existing within the legal boundaries on the effective
date of this rule; however, the subterranean aquifer may extend below
such structures. The subterranean critical habitat includes underground
features in a circle with a radius of 984 ft (300 m) around the
springs.
(4) Critical habitat map units. Data layers defining map units were
created using a geographic information system (GIS), which included
species locations, roads, property boundaries, 2011 aerial photography,
and USGS 7.5' quadrangles. Points were placed on the GIS. We delineated
critical habitat unit boundaries by starting with the cave or spring
point locations that are occupied by the salamanders. From these cave
or springs points, we delineated a 984-ft (300-m) buffer to create the
polygons that capture the extent to which we believe the salamander
populations exist through underground conduits. The polygons were then
simplified to reduce the number of vertices, but still retain the
overall shape and extent. Subsequently, polygons that were within 98 ft
(30 m) of each other were merged together. Each new merged polygon was
then revised to remove extraneous divits or protrusions that resulted
from the merge process. The maps in this entry, as modified by any
accompanying regulatory text, establish the boundaries of the critical
habitat designation. The coordinates or plot points or both on which
each map is based are available to the public at the field office
Internet site (http://www.fws.gov/southwest/es/AustinTexas/), http://www.regulations.gov at Docket No. FWS-R2-ES-2012-0035 and at the
Service's Austin Ecological Services Field Office. You may obtain field
office location information by contacting one of the Service regional
offices, the addresses of which are listed at 50 CFR 2.2.
(5) Unit 1: Barton Springs Unit, Travis County, Texas. Map of Unit
1 follows:
BILLING CODE 4310-55-P
[[Page 50830]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.000
* * * * *
Georgetown Salamander (Eurycea naufragia)
(1) Critical habitat units are depicted for Williamson County,
Texas, on the maps below.
(2) Within these areas, the primary constituent elements of the
physical or biological features essential to the conservation of
Georgetown salamander consist of four components:
(i) Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Georgetown salamander prey base). Hydrologic regimes
similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow for subterranean sites. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 68.4
and 69.8[emsp14][deg]F (20.2 and 21.0 [deg]C), dissolved oxygen
concentrations between 6 and 8 milligrams per liter, and specific water
[[Page 50831]]
conductivity between 604 and 721 microsiemens per centimeter.
(ii) Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat must be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
must have minimal sedimentation.
(iii) Aquatic invertebrates for food. The spring and cave
environments must be capable of supporting a diverse aquatic
invertebrate community that includes crustaceans and insects.
(iv) Subterranean aquifer. During periods of drought or dewatering
on the surface in and around spring sites, access to the subsurface
water table must be provided for shelter and protection.
(3) Surface critical habitat includes the spring outlets and
outflow up to the high water line and 164 ft (50 m) of downstream
habitat, but does not include manmade structures (such as buildings,
aqueducts, runways, roads, and other paved areas) and the land on which
they are located existing within the legal boundaries on the effective
date of this rule; however, the subterranean aquifer may extend below
such structures. The subterranean critical habitat includes underground
features in a circle with a radius of 984-ft (300-m) around the
springs.
(4) Critical habitat map units. Data layers defining map units were
created using a geographic information system (GIS), which included
species locations, roads, property boundaries, 2011 aerial photography,
and USGS 7.5' quadrangles. Points were placed on the GIS. We delineated
critical habitat unit boundaries by starting with the cave or spring
point locations that are occupied by the salamanders. From these cave
or springs points, we delineated a 984 ft (300 m) buffer to create the
polygons that capture the extent to which we believe the salamander
populations exist through underground conduits. The polygons were then
simplified to reduce the number of vertices, but still retain the
overall shape and extent. Subsequently, polygons that were within 98 ft
(30 m) of each other were merged together. Each new merged polygon was
then revised to remove extraneous divits or protrusions that resulted
from the merge process. The maps in this entry, as modified by any
accompanying regulatory text, establish the boundaries of the critical
habitat designation. The coordinates or plot points or both on which
each map is based are available to the public at the field office
Internet site (at Docket No. FWS-R2-ES-2012-0035 and at the Service's
Austin Ecological Services Field Office. You may obtain field office
location information by contacting one of the Service regional offices,
the addresses of which are listed at 50 CFR 2.2.
(5) Index map follows:
[GRAPHIC] [TIFF OMITTED] TP22AU12.001
(6) Unit 1: Cobb Unit, Williamson County, Texas. Map of Unit 1
follows:
[[Page 50832]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.002
(7) Unit 2: Cowen Creek Spring Unit, Williamson County, Texas. Map
of Units 2 and 3 follows:
[[Page 50833]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.003
(8) Unit 3: Bat Well Unit, Williamson County, Texas. Map of Units 2
and 3 is provided at paragraph (7) of this entry.
(9) Unit 4: Walnut Spring Unit,Williamson County, Texas. Map of
Units 4 and 5 follows:
[[Page 50834]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.004
(10) Unit 5: Twin Springs Unit, Williamson County, Texas. Map of
Units 4 and 5 is provided at paragraph (9) of this entry.
(11) Unit 6: Hogg Hollow Spring Unit, Williamson County, Texas. Map
of Units 6, 7, 8, and 9 follows:
[[Page 50835]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.005
(12) Unit 7: Cedar Hollow Spring Unit, Williamson County, Texas.
Map of Units 6, 7, 8, and 9 is provided at paragraph (11) of this
entry.
(13) Unit 8: Lake Georgetown Unit, Williamson County, Texas. Map of
Units 6, 7, 8, and 9 is provided at paragraph (11) of this entry.
(14) Unit 9: Water Tank Cave Unit, Williamson County, Texas. Map of
Units 6, 7, 8, and 9 is provided at paragraph (11) of this entry.
(15) Unit 10: Avant Spring Unit, Williamson County, Texas. Map of
Units 10, 11, 12, and 13 follows:
[[Page 50836]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.006
(16) Unit 11: Buford Hollow Spring Unit, Williamson County, Texas.
Map of Units 10, 11, 12, 13 is provided at paragraph (15) of this
entry.
(17) Unit 12: Swinbank Spring Unit, Williamson County, Texas. Map
of Units 10, 11, 12, and 13 is provided at paragraph (15) of this
entry.
(18) Unit 13: Shadow Canyon Unit, Williamson County, Texas. Map of
Units 10, 11, 12, and 13 is provided at paragraph (15) of this entry.
(19) Unit 14: San Gabriel Springs Unit, Williamson County, Texas.
Map of Unit 14 follows:
[[Page 50837]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.007
Jollyville Plateau Salamander (Eurycea tonkawae)
(1) Critical habitat units are depicted for Travis and Williamson
Counties, Texas, on the maps below.
(2) Within these areas, the primary constituent elements of the
physical or biological features essential to the conservation of
Jollyville Plateau salamander consist of four components:
(i) Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Jollyville Plateau salamander's prey base). Hydrologic
regimes similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow in subterranean habitats. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 65.3
and 67.3[emsp14][deg]F (18.5 and 19.6 [deg]C), dissolved oxygen
concentrations between 5.6 and 7.1 milligrams per liter, and specific
water conductance between 550 and 625 microsiemens per centimeter.
(ii) Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or
[[Page 50838]]
gravel) in the substrate of the salamander's surface aquatic habitat
must be large enough to provide salamanders with cover, shelter, and
foraging habitat. The substrate and interstitial spaces must have
minimal sedimentation.
(iii) Aquatic invertebrates for food. The spring and cave
environments must be capable of supporting a diverse aquatic
invertebrate community that includes crustaceans and insects.
(iv) Subterranean aquifer. During periods of drought or dewatering
on the surface in and around spring sites, access to the subsurface
water table must be provided for shelter and protection.
(3) Surface critical habitat includes the spring outlets and
outflow up to the high water line and 164 ft (50 m) of downstream
habitat, but does not include manmade structures (such as buildings,
aqueducts, runways, roads, and other paved areas) and the land on which
they are located existing within the legal boundaries on the effective
date of this rule; however, the subterranean aquifer may extend below
such structures. The subterranean critical habitat includes underground
features in a circle with a radius of 984 ft (300 m) around the
springs.
(4) Critical habitat map units. Data layers defining map units were
created using a geographic information system (GIS), which included
species locations, roads, property boundaries, 2011 aerial photography,
and USGS 7.5' quadrangles. Points were placed on the GIS. We delineated
critical habitat unit boundaries by starting with the cave or spring
point locations that are occupied by the salamanders. From these cave
or springs points, we delineated a 984-ft (300-m) buffer to create the
polygons that capture the extent to which we believe the salamander
populations exist through underground conduits. The polygons were then
simplified to reduce the number of vertices, but still retain the
overall shape and extent. Subsequently, polygons that were within 98 ft
(30 m) of each other where merged together. Each new merged polygon was
then revised to remove extraneous divits or protrusions that resulted
from the merge process. The maps in this entry, as modified by any
accompanying regulatory text, establish the boundaries of the critical
habitat designation. The coordinates or plot points or both on which
each map is based are available to the public at the field office
Internet site (http://www.fws.gov/southwest/es/AustinTexas/), http://www.regulations.gov at Docket No. FWS-R2-ES-2012-0035 and at the
Service's Austin Ecological Services Field Office. You may obtain field
office location information by contacting one of the Service regional
offices, the addresses of which are listed at 50 CFR 2.2.
(5) Index map follows:
[GRAPHIC] [TIFF OMITTED] TP22AU12.008
(6) Unit 1: Krienke Spring Unit, Williamson County, Texas. Map of
Unit 1 follows:
[[Page 50839]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.009
(7) Unit 2: Brushy Creek Spring Unit, Williamson County, Texas. Map
of Unit 2 follows:
[[Page 50840]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.010
(8) Unit 3: Testudo Tube Cave Unit, Williamson and Travis Counties,
Texas. Map of Units 3, 4, and 5 follows:
[[Page 50841]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.011
(9) Unit 4: Buttercup Creek Cave Unit, Travis and Williamson
County, Texas. Map of Units 3, 4, and 5 is provided at paragraph (8) of
this entry.
(10) Unit 5: Treehouse Cave Unit, Williamson County, Texas. Map of
Units 3, 4, and 5 is provided at paragraph (8) of this entry.
(11) Unit 6: Avery Spring Unit, Williamson County, Texas. Map of
Unit 6 follows:
[[Page 50842]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.012
(12) Unit 7: PC Spring Unit, Williamson County, Texas. Map of Unit
7 follows:
[[Page 50843]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.013
(13) Unit 8: Baker and Audubon Spring Unit, Travis County, Texas,
Map of Unit 8 follows:
[[Page 50844]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.014
(14) Unit 9: Wheless Spring Unit, Travis County, Texas. Map of
Units 9 and 10 follows:
[[Page 50845]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.015
(15) Unit 10: Blizzard R-Bar-B Spring Unit, Travis County, Texas.
Map of Units 9 and 10 in provided at paragraph (14) of this entry.
(16) Unit 11: House Spring Unit, Travis County, Texas. Map of Units
11, 12, and 13 follows:
[[Page 50846]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.016
(17) Unit 12: Kelly Hollow Spring Unit, Travis County, Texas. Map
of Units 11, 12, and 13 is provided at paragraph (16) of this entry.
(18) Unit 13: MacDonald Well Unit, Travis County, Texas. Map of
Units 11, 12, and 13 is provided at paragraph (16) of this entry.
(19) Unit 14: Kretschmarr Unit, Travis County, Texas. Map of Units
14, 15, 16, 17, 18, 19, 20, and 21 follows:
[[Page 50847]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.017
(20) Unit 15: Pope and Hiers Spring Unit, Travis County, Texas. Map
of Units 14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph
(19) of this entry.
(21) Unit 16: Fern Gully Spring Unit, Travis County, Texas. Map of
Units 14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19)
of this entry.
(22) Unit 17: Bull Creek 1 Unit, Travis County, Texas. Map of Units
14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19) of
this entry.
(23) Unit 18: Bull Creek 2 Unit, Travis County, Texas. Map of Units
14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19) of
this entry.
(24) Unit 19: Bull Creek 3 Unit, Travis County, Texas. Map of Units
14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19) of
this entry.
(25) Unit 20: Moss Gulley Spring Unit, Travis County, Texas. Map of
Units 14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19)
of this entry.
(26) Unit 21: Ivanhoe Spring Unit, Travis County, Texas. Map of
Units 14, 15, 16, 17, 18, 19, 20, and 21 is provided at paragraph (19)
of this entry.
(27) Unit 22: Sylvia Spring Unit, Travis County, Texas. Map of
Units 22, 23, 24, and 33 follows:
[[Page 50848]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.018
(28) Unit 23: Tanglewood Spring Unit, Travis County, Texas. Map of
Units 22, 23, 24, and 33 is provided at paragraph (27) of this entry.
(29) Unit 24: Long Hog Hollow Unit, Travis County, Texas. Map of
Units 22, 23, 24, and 33 is provided at paragraph (27) of this entry.
(30) Unit 25: Tributary 3 Unit, Travis County, Texas. Map of Units
25, 26, and 27 follows:
[[Page 50849]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.019
(31) Unit 26: Sierra Spring Unit, Travis County, Texas. Map of
Units 25, 26, and 27 is provided at paragraph (30) of this entry.
(32) Unit 27: Troll Spring Unit, Travis County, Texas. Map of Units
25, 26, and 27 is provided at paragraph (30) of this entry.
(33) Unit 28: Stillhouse Unit, Travis County, Texas. Map of Units
28, 29, 30, and 31 follows:
[[Page 50850]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.020
(34) Unit 29: Salamander Cave Unit, Travis County, Texas. Map of
Units 28, 29, 30, 31 is provided at paragraph (33) of this entry.
(35) Unit 30: Indian Spring Unit, Travis County, Texas. Map of
Units 28, 29, 30, and 31 is provided at paragraph (33) of this entry.
(36) Unit 31: Spicewood Spring Unit, Travis County, Texas. Map of
Units 28, 29, 30, and 31 is provided at paragraph (33) of this entry.
(37) Unit 32: Balcones District Park Spring Unit, Travis County,
Texas. Map of Unit 32 follows:
[[Page 50851]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.021
(38) Unit 33: Tributary 4 Unit, Travis County, Texas. Map of Units
22, 23, 24, and 33 is provided at paragraph (27) of this entry.
* * * * *
Salado Salamander (Eurycea chisholmensis)
(1) Critical habitat units are depicted for Bell County, Texas, on
the maps below.
(2) Within these areas, the primary constituent elements of the
physical or biological features essential to the conservation of Salado
salamander consist of four components:
(i) Water from the Northern Segment of the Edwards Aquifer. The
groundwater must be similar to natural aquifer conditions both
underground and as it discharges from natural spring outlets.
Concentrations of water quality constituents that could have a negative
impact on the salamander should be below levels that could exert direct
lethal or sublethal effects (such as effects to reproduction, growth,
development, or metabolic processes), or indirect effects (such as
effects to the Salado salamander's prey base). Hydrologic regimes
similar to the historical pattern of the specific sites must be
present, with at least temporal surface flow for spring sites and
continuous flow for subterranean sites. The water chemistry must be
similar to natural aquifer conditions, with temperatures between 65.3
and 69.8[emsp14][deg]F (18.5 and 21.0 [deg]C), dissolved oxygen
[[Page 50852]]
concentrations between 5.6 and 8 milligrams per liter, and conductivity
between 550 and 721 microsiemens per centimeter.
(ii) Rocky substrate with interstitial spaces. Rocks (boulders,
cobble, or gravel) in the substrate of the salamander's surface aquatic
habitat must be large enough to provide salamanders with cover,
shelter, and foraging habitat. The substrate and interstitial spaces
must have minimal sedimentation.
(iii) Aquatic invertebrates for food. The spring and cave
environments must be capable of supporting a diverse aquatic
invertebrate community that includes crustaceans and insects.
(iv) Subterranean aquifer. During periods of drought or dewatering
on the surface in and around spring sites, access to the subsurface
water table must be provided for shelter and protection.
(3) Surface critical habitat includes the spring outlets and
outflow up to the high water line and 164 ft (50 m) of downstream
habitat, but does not include manmade structures (such as buildings,
aqueducts, runways, roads, and other paved areas) and the land on which
they are located existing within the legal boundaries on the effective
date of this rule; however, the subterranean aquifer may extend below
such structures. The subterranean critical habitat includes underground
features in a circle with a radius of 984 ft (300 m) around the
springs.
(4) Critical habitat map units. Data layers defining map units were
created using a geographic information system (GIS), which included
species locations, roads, property boundaries, 2011 aerial photography,
and USGS 7.5' quadrangles. Points were placed on the GIS. We delineated
critical habitat unit boundaries by starting with the cave or spring
point locations that are occupied by the salamanders. From these cave
or springs points, we delineated a 984-ft (300-m) buffer to create the
polygons that capture the extent to which we believe the salamander
populations exist through underground conduits. The polygons were then
simplified to reduce the number of vertices, but still retain the
overall shape and extent. Subsequently, polygons that were within 98 ft
(30 m) of each other where merged together. Each new merged polygon was
then revised to remove extraneous divits or protrusions that resulted
from the merge process. The maps in this entry, as modified by any
accompanying regulatory text, establish the boundaries of the critical
habitat designation. The coordinates or plot points or both on which
each map is based are available to the public at the field office
Internet site (http://www.fws.gov/southwest/es/AustinTexas/), http://www.regulations.gov at Docket No. FWS-R2-ES-2012-0035 and at the
Service's Austin Ecological Services Field Office. You may obtain field
office location information by contacting one of the Service regional
offices, the addresses of which are listed at 50 CFR 2.2.
(5) Index map follows:
[GRAPHIC] [TIFF OMITTED] TP22AU12.022
(6) Unit 1: Hog Hollow Spring Unit, Bell County, Texas. Map of
Units 1, 2, and 3 follows:
[[Page 50853]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.023
(7) Unit 2: Solana Spring 1 Unit, Bell County, Texas. Map
of Units 1, 2, and 3 is provided at paragraph (6) of this entry.
(8) Unit 3: Cistern Spring Unit, Bell County, Texas. Map of Units
1, 2, and 3 is provided at paragraph (6) of this entry.
(9) Unit 4: IH-35 Unit, Bell County, Texas. Map of Unit 4 follows:
[[Page 50854]]
[GRAPHIC] [TIFF OMITTED] TP22AU12.024
* * * * *
Dated: July 31, 2012.
Rachel Jacobson,
Principal Deputy Assistant Secretary for Fish and Wildlife and Parks.
[FR Doc. 2012-19659 Filed 8-21-12; 8:45 am]
BILLING CODE 4310-55-C