[Federal Register Volume 76, Number 153 (Tuesday, August 9, 2011)]
[Proposed Rules]
[Pages 48777-48788]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-20054]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2011-0057; MO 92210-0-0008 B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List the Nueces River and Plateau Shiners as
Threatened or Endangered
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list the Nueces River shiner
(Cyprinella sp.) and plateau shiner (Cyprinella lepida) as threatened
or endangered and to designate critical habitat under the Endangered
Species Act of 1973, as amended (Act). After review of all available
scientific and commercial information, we find that listing the Nueces
River and plateau shiners is not warranted at this time. However, we
ask the public to submit to us any new information that becomes
available concerning the threats to the Nueces River and plateau
shiners or their habitats at any time.
DATES: The finding announced in this document was made on August 9,
2011.
ADDRESSES: This finding is available on the Internet at http://
[[Page 48778]]
www.regulations.gov at Docket Number [FWS-R2-ES-2011-0057]. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Austin Ecological Services Field Office,
10711 Burnet Road, Suite 200, Austin, TX 78758. Please submit any new
information, materials, comments, or questions concerning this finding
to the above address.
FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor,
Austin Ecological Services Field Office (see ADDRESSES); by telephone
at 512-490-0057, extension 248; or by facsimile at 512-490-0974. If you
use a telecommunications device for the deaf (TDD), please call the
Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Endangered Species Act of 1973, as
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition
to revise the Federal Lists of Endangered and Threatened Wildlife and
Plants that contains substantial scientific or commercial information
that listing the species may be warranted, we make a finding within 12
months of the date of receipt of the petition. In this finding, we will
determine that the petitioned action is: (1) Not warranted, (2)
warranted, or (3) warranted, but the immediate proposal of a regulation
implementing the petitioned action is precluded by other pending
proposals to determine whether species are threatened or endangered,
and expeditious progress is being made to add or remove qualified
species from the Federal Lists of Endangered and Threatened Wildlife
and Plants. Section 4(b)(3)(C) of the Act requires that we treat a
petition for which the requested action is found to be warranted but
precluded as though resubmitted on the date of such finding, that is,
requiring a subsequent finding to be made within 12 months. We must
publish these 12-month findings in the Federal Register.
Previous Federal Actions
On June 25, 2007, we received a petition dated June 18, 2007, from
Forest Guardians (now WildEarth Guardians), requesting that 475 species
in the southwestern United States, including the Nueces River and
plateau shiners, be listed under the Act and critical habitat be
designated. We acknowledged the receipt of the petition in a letter to
the petitioner, dated July 11, 2007. In that letter we also stated that
the petition was under review by staff in our Southwest Regional
Office.
On March 19, 2008, WildEarth Guardians filed a complaint alleging
that the Service failed to comply with its mandatory duty to make a
preliminary 90-day finding on the June 18, 2007, petition to list 475
southwest species. We subsequently published an initial 90-day finding
for 270 of the 475 petitioned species on January 6, 2009 (74 FR 419),
concluding that the petition did not present substantial information
that listing of those 270 species may be warranted. This initial 90-day
finding did not include the Nueces River and plateau shiners.
Subsequently, on March 13, 2009, the Service and WildEarth Guardians
filed a stipulated settlement agreement, agreeing that the Service
would submit to the Federal Register a finding as to whether their
petition presented substantial information indicating that the
petitioned action may be warranted for the remaining 192 southwestern
species by December 9, 2009. On December 16, 2009 (74 FR 66866), we
published a second 90-day finding for the remaining 192 southwestern
species, which included a determination that listing the Nueces River
and plateau shiners may be warranted, and initiated a status review.
This notice constitutes the 12-month finding on the June 18, 2007,
petition to list the Nueces River and plateau Shiners as threatened or
endangered with critical habitat.
Species Information
Taxonomy and Species Description
There has been some confusion and inconsistency regarding the
taxonomy of the Nueces River and plateau shiners. Currently, there are
approximately 30 species that belong to the genus Cyprinella, of which
both species of shiners are members (Nelson et al. 2004, p. 69;
Schonhuth and Mayden 2010, p. 77). The taxonomy within this genus has
been associated with extensive confusion because similarities in body
characteristics have made it difficult to differentiate between species
(Schonhuth and Mayden 2010, p. 77). Fortunately, much of this confusion
is being resolved with advances in genetic analysis (Schonhuth and
Mayden 2010, pp. 77-98). However, there are still outstanding taxonomic
issues that need to be resolved to clarify any potential confusion
between the Nueces River and plateau shiners.
When first described, the Nueces River and plateau shiners were not
considered separate species. They were both originally described as the
plateau shiner, Cyprinella lepida, by Girard in 1856 (Richardson and
Gold 1995, p. 29). Nearly 100 years later, both species were still
thought to be one species. For example, Hubbs (1954, pp. 277-291)
recognized only one species as distinct, the plateau shiner, Notropis
(=Cyprinella) lepidus, occurring in the Nueces, Frio, and upper
Guadalupe Rivers. However, Mayden (1989, p. 60) later pointed out that
the shiner Hubbs (1954, pp. 277-291) referred to in the upper Guadalupe
River was actually a red shiner species, Notropis (=Cyprinella)
lutrensis, and not the plateau shiner.
Morphological studies conducted by Matthews (1987, pp. 616-637) and
Mayden (1989, pp. 58-60) provided support that Cyprinella lepida was a
distinct and valid species occurring in the Nueces, Frio, and Sabinal
Rivers of the Nueces River basin (Figure 1). However, Matthews (1987,
p. 269) noted that there were morphological differences between
specimens collected in the Nueces and Frio Rivers, but did not suggest
that there were two separate taxonomic entities. One of the main
differences was breeding coloration in male specimens collected in the
Frio River; these male specimens had red on the tip of their snouts
(Matthews 1987, pp. 632-634). The male specimens collected in the
Nueces River exhibited no breeding coloration (Matthews 1987, pp. 632-
634).
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[GRAPHIC] [TIFF OMITTED] TP09AU11.013
These morphological differences between the Nueces and Frio Rivers'
shiners were validated by genetic investigations that revealed two
distinct lineages within populations of Cyprinella lepida. In 1987 and
1988, Richardson and Gold (1995, p. 29) conducted a genetic study on
Cyprinella lepida, in which they (Richardson and Gold 1995, p. 29)
collected individuals from the Nueces, Frio, and Sabinal Rivers. The
results of their genetic analysis showed that Cyprinella lepida in the
Frio and Sabinal Rivers was a distinct species from Cyprinella lepida
collected in the Nueces River (Richardson and Gold 1995, pp. 31-33).
Specimens collected in the Frio River were very similar genetically to
specimens collected in the Sabinal River (Richardson and Gold 1995, p.
31). However, specimens collected from the Frio and Sabinal Rivers were
quite different genetically from specimens collected in the Nueces
River (Richardson and Gold 1995, p. 31). The genetic differences, along
with the observed morphological differences, led Richardson and Gold
(1995, pp. 31-33) to conclude that Cyprinella in the Frio and Sabinal
Rivers was a distinct species from those in the Nueces River. Since
1995, the population in the Nueces River has been referred to as the
Nueces River shiner, an unnamed species within Cyprinella, while
populations in the Frio and Sabinal Rivers have kept the kept the name
plateau shiner, Cyprinella lepida. Formal naming of the Nueces River
shiner, Cyprinella sp., is still pending.
Further genetic investigations by Richardson and Gold (1999)
supported their previous conclusion that Cyprinella in the Frio and
Sabinal Rivers is a distinct species from those in the Nueces River. In
this study, Richardson and Gold (1999, p. 50) focused on variation in
mitochondrial genes in the five species of the shiner group inhabiting
the southwestern United States, which included specimens of Cyprinella
lepida from the Frio River and Cyprinella sp. from the Nueces River.
Based on results of this study, Richardson and Gold (1999, p. 55) were
hesitant to promote a sister relationship between the Nueces River
shiner, Cyprinella sp., and the plateau shiner, Cyprinella lepida,
meaning that the two lineages were not closely related. Instead, they
concluded that the Nueces River shiner and plateau shiner were not as
closely related to each other as they were to other species within the
Cyprinella genus (Richardson and Gold 1999, p. 55).
Another genetic study agreed that the Nueces River shiner and
plateau shiner are distinct species. In 2000, Broughton and Gold (pp.
1-10) conducted a genetic analysis of all Cyprinella species found
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in the United States. As part of their methodology, Broughton and Gold
(2000, p. 5) grouped the Nueces and Plateau shiners into the same
species, Cyprinella lepida, but did make the distinction that
``Cyprinella lepida-a'' from the Frio River were not closely related to
``Cyprinella lepida-b'' from the Nueces River.
In an effort to clarify some of the genus' taxonomic confusion,
Schonhuth and Mayden (2010, pp. 77-98) conducted a genetic study of all
species within the Cyprinella genus, with a more exhaustive focus on
the problematic taxa. Results from Schonhuth and Mayden's (2010, p. 91)
genetic analysis were consistent with previous genetic studies:
Cyprinella lepida in the Sabinal and Frio Rivers are genetically
separate and distinct from the Cyprinella sp. found in the Nueces
River. Genetic differences between specimens from the Sabinal and Frio
Rivers were very different from those collected in the Nueces River,
enough so that Schonhuth and Mayden (2010, p. 91) recommended leaving
them as separate species.
Despite the morphological and genetic studies of the Nueces River
and plateau shiners, the scientific community has been inconsistent in
recognizing these shiners as separate species. The Texas Parks and
Wildlife Department (TPWD) recognizes the plateau shiner (Cyprinella
lepida) and Nueces River shiner (Cyprinella sp.) as separate species
(Norris et al. 2005, p. 10). However, Phillips et al. (2010, p. 130)
failed to recognize the Nueces River shiner as a separate species
during a study on sound production and spawning behavior. In fact,
Phillips et al. (2010, p. 130) stated that they collected Cyprinella
lepida with seines from the Nueces River 0.5 mi (0.8 km) west of Camp
Wood, Real County, Texas, during December 2002 and March 2003, and
transferred them to a lab to do an acoustic study on spawning behavior.
It is not clear whether Phillips et al. (2010) collected actual plateau
shiners from the Nueces River, or whether they collected Nueces River
shiners but mistakenly called them plateau shiners. Phillips et al.
(2010) did not mention the name Nueces River shiner, Cyprinella sp.,
nor did they mention how they determined that the fish were Cyprinella
lepida. To add further confusion, acceptance of the Nueces River
shiner, Cyprinella sp., as a separate species from the plateau shiner,
Cyprinella lepida, by the American Fisheries Society (2004, p. 69) is
still pending. On the other hand, Hubbs et al. (2008, p. 19) recognized
the Nueces River and plateau shiners as separate species in their
annotated checklist of the freshwater fishes of Texas. Because there is
still inconsistency, a formal systematic description by the scientific
community of the Nueces River shiner, Cyprinella sp., is needed.
Based on the best available science, we accept the characterization
of the Nueces River shiner, Cyprinella sp., and the plateau shiner,
Cyprinella lepida, as separate species. We base this distinction on the
morphological and genetic research conducted by Richardson and Gold
(1995, pp. 28-37), Edwards et al. (2008, pp. 1-30), and Schonhuth and
Mayden (2010, pp. 77-98), and due to the fact that this research has
been accepted by much of the scientific community (Hubbs et al. 2008,
p. 19). However, we recognize there is a need for more extensive
morphological, genetic, and life history research with more thorough
species characterizations and formal descriptions of these two shiners,
especially for the Nueces River shiner. Because we recognize these two
shiners as separate species, we conduct separate five-factor analyses
below under section 4(a)(1) of the Act to determine whether either
species meets the definition of threatened or endangered. However, we
address both species in this finding because they occur in nearby
watersheds and could be subject to the similar threats.
Distribution
Because of the inconsistencies in taxonomy and species descriptions
of the Nueces River and plateau shiners, there has been similar
confusion and inconsistencies regarding these shiners' distribution.
However, one thing that has been clearly understood is that both the
historic and current range of both shiners is the uppermost headwaters
of the Nueces, Frio, and Sabinal Rivers of the Nueces River basin
(Figure 1). The Nueces River basin covers approximately 17,000 square
miles (44,030 square kilometers), encompassing all or part of 23
counties in south-central Texas (Nueces River Authority 2010, p. 1).
Rivers within the basin include Nueces, Frio, Leona, Sabinal, and
Atascosa Rivers (Nueces River Authority 2010, p. 1). Because the Nueces
River basin is so large, running from the Edwards Plateau region of
Texas to the Gulf Coast of Mexico, there are large physical and
chemical differences between streams in the upper and lower parts of
the basin (Norris et al. 2005, p. 1; Nueces River Authority 2010, p.
1). The differences between the upper and lower parts may be why the
Nueces River and plateau shiners are only found in the upper, cooler
headwaters.
The upper Nueces River basin, where the Nueces River and plateau
shiners are found, is composed of three main tributary systems: The
Nueces, Frio, and Sabinal Rivers (Edwards et al. 2008, p. 2). The
plateau shiner is an endemic (native to and generally confined to a
particular region) minnow that inhabits clear, spring-fed streams over
gravel limestone substrates in the uppermost headwaters of the Frio and
Sabinal Rivers on the Edwards Plateau (Edwards et al. 2004, p. 261;
Edwards et al. 2008, p. 2; Hubbs et al. 2008, p. 19). Meanwhile, the
Nueces River shiner is an endemic minnow that is only found in the
uppermost headwaters of the Nueces River, which is also on the Edwards
Plateau (Edwards et al. 2004, p. 261; Hubbs et al. 2008, p. 19).
An example of the inconsistency in the species' distribution
occurred when TPWD associated the plateau and Nueces River shiners with
the wrong stream segments in their 2005 designation of ecologically
significant stream segments, which are stream segments designated based
on factors related to biological function, hydrologic function,
presence of riparian conservation areas, high water quality,
exceptional aquatic life, high aesthetic value, threatened or
endangered species, and uniqueness (Norris et al. 2005, pp. 16-19).
Norris et al. (2005, pp. 16-19) stated that the Nueces River shiner
occurred in the Frio and Sabinal River, and the plateau shiner occurred
in the Nueces River (p. 17). However, this inconsistency may have
occurred because of the confusion associated with the species'
taxonomy, even though TPWD recognized the Nueces River and plateau
shiners as two separate species (Norris et al. 2005, p. 10).
In a recent study, Edwards et al. (2008, p. 3) attempted to
estimate the current distributional range of plateau shiner in the Frio
and Sabinal Rivers, and Nueces River shiner in the Nueces River. During
their seasonal sampling from 2007 to 2008, Edwards et al. (2008, p. 5)
captured over 11,700 individuals of 24 species, including the Nueces
River and plateau shiners. They noted that the Frio, Sabinal, and
Nueces Rivers were all dominated by fishes that are typical of spring-
fed headwater central Texas streams, but added that there is still
incomplete knowledge of the current range of the plateau shiner in the
Frio and Sabinal Rivers, and of the Nueces River shiner in the upper
Nueces River (Edwards et al. 2008, p. 3). Based on the best available
information, we believe that the Nueces River and
[[Page 48781]]
plateau shiners' historical and current ranges are the uppermost
headwaters of the Sabinal, Frio, and Nueces Rivers in the Edwards
Plateau region of Texas, but the extent of their ranges remains to be
determined.
Habitat
There is limited information in the literature regarding the Nueces
River and plateau shiners' habitat. Edwards et al. (2004, p. 261) noted
that the plateau shiner inhabited clear, spring-fed streams over gravel
limestone substrates. Phillips et al. (2010, p. 133) noted that
Cyprinella collected out of the Nueces River in 2002 and 2004 were
crevice spawners (females release their eggs in crevices), like the
majority of other Cyprinella species. Also, Phillips et al. (2010, p.
133) noted that the specimens they collected relied on spring or
spring-fed water. Although not specified to species, we assume that the
Cyprinella Phillips et al. (2010, p. 133) referred to were Nueces River
shiners based on where the specimens were collected. In any case, it is
apparent that both shiners' habitat is spring-fed streams, which are
typically found in the headwaters. Furthermore, the headwater streams
where both Nueces River and plateau shiners occur are characterized by
limestone bedrock with significant gravel and cobble bottoms, clear
evidence of spring-flows with emergent vegetation and relatively
shallow depths, relatively high pH values typical of limestone bedrock
streams of the Edwards Plateau, relatively stable water temperatures,
and dissolved oxygen levels generally around 10 parts per million
(Edwards et al. 2008, p. 21). Though limited, this information is
consistent with what is known about the shiners' habitat.
Population Abundance
There has been much speculation and very little research actually
surveying and documenting the abundance of the Nueces River and plateau
shiners. A genetic study by Richardson and Gold (1995, p. 35) noted
that the plateau shiner's abundance appeared to have decreased
considerably over the previous 20 years prior to their study. However,
their note of plateau shiner abundance was not based on actual surveys
or data collection (Richardson and Gold 1995, p. 35). Also, we could
not find any evidence or documentation that either of these shiners'
abundance actually declined over this time period. Therefore, we cannot
conclude that there was a decline in the Nueces River or plateau
shiners over the 20 years prior to Richardson and Gold's (1995) study.
Because of Richardson and Gold's (1995, p. 35) statement regarding
the presumed decline of the two shiners, other researchers cited
Richardson and Gold while making the same conjecture. For example,
Hoagstrom et al. (2011, p. 24) claimed that 41 endemic fishes,
including plateau and Nueces River shiners, were declining in the
plains of North America because of dewatering, low flows, habitat
fragmentation, nonnative species, and pollution. However, this
presumption was based on the Richardson and Gold (1995) genetic study
discussed above rather than on actual abundance data or surveys.
There has been a noted decline throughout Texas for many of the
State's native fishes (Hubbs et al. 2008, p. 2). Nonnative species, as
well as degradation of water and habitat quality, are thought to be
major components of the native fishes' decline (Hubbs et al. 2008, p.
5). As part of the annotated checklist of the freshwater fishes of
Texas, Hubbs et al. (2008, p. 19) identified both the Nueces River and
plateau shiners as species of special concern. Hubbs et al. (2008, p.
5) defined a species of ``special concern'' as a taxon whose abundance
or range has been reduced to the degree that it may be threatened with
extinction or whose range is only peripherally in Texas and could be
easily extirpated. Some species were included in this category of
special concern because up-to-date information concerning their status
was unavailable or fragmentary (Hubbs et al. 2008, p. 5). In any case,
Hubbs et al. (2008) provided no evidence for categorizing the Nueces
River and plateau shiners as species of special concern. There was no
supporting information on abundance, range reduction, or any other
reason for classifying these two fishes as species of special concern.
Therefore, it is reasonable to assume that Hubbs et al. (2008)
classified the Nueces River and plateau shiners as a species of special
concern because there was no up-to-date information concerning their
status.
Contrary to the information above, other studies have noted that
the Nueces River and plateau shiners were abundant within the past
decade in the headwaters of the Sabinal, Frio, and Nueces Rivers
(Figure 1). In fact, Edwards et al. (2004, p. 261) stated that the
plateau shiner was moderately abundant in the Edwards Plateau region.
To obtain a more thorough assessment on the status of the Nueces River
and plateau shiners, Edwards et al. (2008, p. 6) conducted a sampling
study from 2007 to 2008 in the Nueces, Frio, and Sabinal Rivers and
found that the Nueces River and plateau shiners were two of the most
abundant fishes in each of these rivers out of 21 different species
collected.
Even though there have been claims in the scientific literature
that the Nueces River and plateau shiners were declining, these claims
appear to be unsubstantiated by actual survey data. On the other hand,
a recent study conducted by Edwards et al. (2008, pp. 1-30) that
surveyed abundance of the Nueces River and plateau shiners found large
numbers of these species. In conclusion, there is insufficient evidence
to determine population trends for either species.
Summary of Information Pertaining to the Five Factors
Section 4 of the Act (16 U.S.C. 1533) and implementing regulations
(50 CFR part 424) set forth procedures for adding species to, removing
species from, or reclassifying species on the Federal Lists of
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of
the Act, a species may be determined to be endangered or threatened
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; or
(E) Other natural or manmade factors affecting its continued
existence.
In making this finding, information pertaining to the Nueces River
and plateau shiners in relation to the five factors provided in section
4(a)(1) of the Act is discussed below. In making our 12-month finding
on the petition, we considered and evaluated the best available
scientific and commercial information. We reviewed the petition,
information available in our files, and other available published and
unpublished information. We also consulted with recognized fish experts
and biologists with TPWD and The Nature Conservancy.
Summary of Information Pertaining to the Five Factors for Nueces River
Shiner
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
The following factors have the potential to affect the habitat or
range of the Nueces River shiner: Livestock grazing, water quantity,
water quality,
[[Page 48782]]
and land use. Below, we discuss in detail each of these factors and
determine whether or not they constitute a threat to the species.
Livestock Grazing
While we know that livestock grazing occurs within the range of the
species, we could find no information on the extent or intensity of
historical or current livestock grazing practices or the impact grazing
might have on the Nueces River shiner and its habitat. In areas where
livestock are grazed inappropriately, impacts could include, but are
not limited to, runoff from disturbed stream banks, livestock urine and
manure deposited into streams, disturbance and erosion from trampled
banks, and increased solar exposure due to reduced shade from
streamside vegetation and loss of undercut streambanks. Any of these
impacts could affect the Nueces River shiner by degrading water quality
and negatively impacting the species. Richardson and Gold (1995, p. 35)
concluded that much of the land in the Nueces River basin is used for
agriculture, and that overgrazing by cattle posed serious problems for
aquatic fauna. However, we found no monitoring data indicating that
water quality degradation associated with livestock grazing is
occurring within the range of the Nueces River shiner. Based on the
best available information, we could find no evidence that overgrazing
is posing a threat to the Nueces River shiner or is likely to in the
future. Therefore, because the best available information does not
indicate that livestock grazing is negatively impacting the species, we
find that the Nueces River shiner is not in danger of extinction now or
in the foreseeable future as a result of livestock grazing.
Water Quantity
Diminished water flows can cause losses in habitat diversity,
reduce stream productivity, and degrade water quality for many fish
species (Norris et al. 2005, p. 1). Richardson and Gold (1995, p. 35)
suggested that groundwater (underground aquifer) levels for much of
south-central Texas had decreased substantially over the decade
preceding their study (1980s), resulting in significantly reduced water
flow in spring-fed rivers, including the habitat of the Nueces River
shiner. Although there is evidence of stream flow fluctuations that
most likely relate to annual rainfall events, the best available
information does not indicate that reduced stream flows are occurring
within the range of the Nueces River shiner at a level that may
adversely impact the species. As we have noted previously, the Nueces
River shiner is an endemic minnow that is only found in the uppermost
headwaters of the Nueces River within the Edwards Plateau (Edwards et
al. 2004, p. 261; Hubbs et al. 2008, p. 19). Over the past century in
the Edwards Plateau region of Texas, there has been evidence of some
loss of natural spring and headwater stream flows (Edwards et al. 2004,
p. 253). Yet, water users in the Edwards Plateau are altering their
usage of waters from the aquifers of the Edwards Plateau. Reduced water
usage has allowed for the conservation of regional spring flows
(Edwards et al. 2004, p. 263). Additionally, stream flow monitoring is
occurring at various sites within the Nueces River shiner's range by
the United States Geological Survey (Edwards et al. 2008, p. 25), and
Edwards et al. (2008, p. 25) analyzed these stream flow measurements in
the Frio, Sabinal, and Nueces Rivers for the last decade. Results of
Edward's et al. (2008, p. 25) analysis showed that there was a normal
range of flow variation in each of the streams due to natural rainfall
events. Edwards et al. (2008, p. 6) also noted that the Nueces River
shiner was one of the most abundant fishes in the upper stream segments
of the Nueces River. Thus, the stream flow variation was occurring at a
level that had no known impact on the species. While there may be
fluctuations in stream flow, there is no evidence indicating that
reduced water flow is a threat to the species either now or in the
foreseeable future. Therefore, we find that the Nueces River shiner is
not in danger of extinction now or in the foreseeable future as a
result of reduced water flow.
Water Quality
Within the last 12 years, there has been cause for concern along
certain stream segments of the Nueces River. In 1999, a 91-mile (mi)
(147-kilometers (km)) stream segment of Nueces River that flows from
Holland Dam in La Salle County to its confluence with the Frio River at
the Choke Canyon Reservoir in Live Oak County was included in the State
of Texas' Clean Water Act 303(d) list as impaired due to concentrations
of dissolved oxygen below the minimum standards criteria in the lower
25-mi (40-km) portion of the stream (Bonner et al. 2005, p. 1; Nueces
River Authority 2010, p. 13). Adequate dissolved oxygen is necessary
for respiration and other essential processes of aquatic organisms;
thus, low levels may be detrimental to the health of aquatic organisms.
The majority of this lower 25-mi (40-km) portion of the stream occurs
in McMullen County, which lies in the South Texas Brush Country region
of Texas, well outside the historical and current range of the Nueces
River shiner. As noted above in the Species Information section, the
Nueces River shiner's range occurs in the uppermost headwaters in the
Edwards Plateau region of Texas. Therefore, the concerns about low
dissolved oxygen content associated with this segment of Nueces River
do not relate to the Nueces River shiner or its range.
Based on the best available scientific and commercial information,
there is no evidence that pollution causing diminished water quality
may be having an impact on the Nueces River shiner or its habitat. In
2005, the TPWD reported the Nueces River as having high water quality
and exceptional aquatic life (Norris et al. 2005, p. 17). Also, the
TPWD designated stream segments in the upper Nueces River as
ecologically significant based on low levels of development in the
watershed, no point sources of pollution, no channelization, and no
atypical nonpoint sources of pollution (Norris et al. 2005, p. 5).
Furthermore, water quality monitoring has been conducted in the
uppermost reaches of the Nueces River where the majority of Nueces
River shiners occur, and no problems have been found (Nueces River
Authority 2010, p. 17). Therefore, we find that the Nueces River shiner
is not in danger of extinction now or in the foreseeable future as a
result of diminished water quality caused by pollution.
Land Use
The decline of native fishes in the southern United States
generally is attributable to pervasive, complex habitat degradation
across the landscape that both reduces and fragments habitat and
increases isolation of fish populations (Warren et al. 2000, p. 8).
Often, physical habitat alteration in the form of channelization,
impoundment, sedimentation, and flow modification are frequently
associated with fish declines (Warren et al. 2000, p. 8).
Edwards et al. (2008, p. 3) mentioned potential impacts to the
Nueces River from existing agricultural practices, land use changes,
and groundwater pumping, and stated that these have combined to create
stream segments identified as impaired under section 303(d) of the
Clean Water Act. One of the main purposes of the Edwards et al. (2008,
p. 3) study was to find out if these potential impacts may actually be
a factor in population and range declines among native fishes,
including the Nueces River shiner. In order to determine the extent of
these potential
[[Page 48783]]
impacts, Edwards et al. (2008, p. 27) looked at the biological
integrity of streams in the upper Nueces River and found that the
Nueces River had high water quality within the range of the Nueces
River shiner. Also, Edwards et al. (2008, p. 29) noted that the fish
fauna sampled are typically associated with high-quality spring-fed
streams within the southern Edwards Plateau. On the other hand, Edwards
et al. (2008, p. 27) noted some impacts along the upper Nueces River,
such as development along the watercourse and recreational pressures
during the summer months. Even with these impacts, the headwater
streams of the Nueces River basin maintained much of their integrity as
evidenced by such fish as the Nueces River shiner (Edwards et al. 2008,
p. 27). In fact, Edwards et al. (2008, p. 6) stated that the Nueces
River shiner was one of the most abundant fishes in the upper stream
segments of the Nueces River. Further, The Nature Conservancy of Texas
is currently engaged in watershed protection in the upper Nueces River
basin, mainly as a participant in the City of San Antonio's Aquifer
Protection Program (Edwards et al. 2008, p. 3). The Nature Conservancy
holds several conservation easements and is exploring ways to increase
conservation efforts in this part of the river basin (Edwards et al.
2008, p. 3). Therefore, we find no evidence indicating that land uses
are negatively impacting the Nueces River shiner now or in the
foreseeable future.
Summary of Factor A
We relied on the best available scientific and commercial
information, which does not indicate that these or any factors are
impacting the Nueces River shiner at a level that may impact the
species. Therefore, we find that the Nueces River shiner is not in
danger of extinction now or in the foreseeable future as a result of
destruction, modification, or curtailment of its habitat or range.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Based on the best available scientific and commercial information,
there is no evidence that impacts are occurring to the Nueces River
shiner or its habitat under this factor. Other than the scientific
studies referenced in this finding, this shiner is not used for any
commercial, recreational, or educational purposes. Therefore, we find
that the Nueces River shiner is not in danger of extinction now or in
the foreseeable future as a result of overutilization for commercial,
recreational, scientific, or educational purposes.
Factor C. Disease or Predation
We are not aware of any research that has been conducted to examine
disease or predation in the Nueces River shiner. Also, we are not aware
of any nonnative species that may prey on the Nueces River shiner.
Therefore, based on the best available scientific and commercial
information, we find that the Nueces River shiner is not in danger of
extinction now or in the foreseeable future as a result of disease or
predation.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
To determine if existing regulatory mechanisms are adequate to
protect the Nueces River shiner, we evaluated agreements and laws in
effect within the range of the species. One regulatory mechanism is the
Clean Water Act (CWA), which was established in 1972. The CWA is the
primary Federal law addressing water pollution in the United States.
The purpose of the CWA is to stop pollutants from being discharged into
waterways and to maintain water quality to provide a safe environment
for fishing, swimming, and drinking. All navigable waters in the United
States are covered under the CWA. The CWA provides guidelines and
offers Federal financial assistance for identifying the causes of
pollution. There are standards and regulations that must be adhered to
by industries that discharge into waterways. The CWA sets forth water
quality standards that are site-specific allowable pollutant levels for
individual water bodies, such as rivers, lakes, streams, and wetlands.
State agencies are required by the CWA to set water quality standards
by designating uses for the water body (e.g., recreation, water supply,
aquatic life, and agriculture) and applying water quality criteria to
protect the designated uses.
In Texas, the Texas Commission on Environmental Quality (TCEQ),
formerly known as Texas Natural Resource Conservation Commission, is
the environmental agency that oversees water quality standards as
required by the CWA (TCEQ 2010b, p. 19). The TCEQ strives to protect
Texas' human and natural resources consistent with sustainable economic
development, by providing clean air, clean water, and the safe
management of waste (TCEQ 2010b, p. 4). The TCEQ key operations
include, but are not limited to, issuing, administering, renewing, and
modifying permits, water rights, licenses, or certifications for
organizations and individuals whose activities have some potential or
actual environmental impact that must be formally authorized by the
agency; monitoring the current condition of a geographic area or
natural resource, often through sampling or surveys; and identifying,
verifying, and tracking violations of regulations and initiating
enforcement actions in response to violations (TCEQ 2010b, p. 21). The
TCEQ developed the Clean Rivers Program to implement the goals of the
Texas Clean Rivers Act (TCRA), described below.
The TCRA, which was passed in 1991 by the Texas legislature,
requires that basinwide water quality assessments be conducted for each
river basin in Texas (Nueces River Authority 2010, p. 1). The goal of
the TCRA is to provide waterways in the State with coordinated
monitoring and protection, to identify the locations of water quality
problems, and develop solutions on a river basin by river basin basis.
The Clean Rivers Program is a partnership involving the TCEQ, other
State agencies, river authorities, local governments, industry, and
citizens (Nueces River Authority 2010, p. 1). Also, the Nueces River
Authority was created in 1935 by special act of the 44th Texas
Legislature codified as Article 8280-115 (Texas Water Code Auxiliary
Laws, as amended). Under supervision of the TCEQ, the Nueces River
Authority has broad authority to preserve, protect, and develop surface
water resources, including flood control, irrigation, navigation, water
supply, wastewater treatment, and water quality control. The Nueces
River Authority serves all or parts of 22 counties in Texas, covering
over 17,000 square miles (44,030 square kilometers), including the
drainage area of the Nueces River and its tributaries and the adjoining
coastal basins.
Under the Clean Rivers Program and using a watershed management
approach, the Nueces River Authority and TCEQ work together to identify
and evaluate surface water quality issues and to establish priorities
for corrective action within the Nueces River basin (Nueces River
Authority 2010, p. 1). The Nueces River Authority and TCEQ conduct
quarterly water quality monitoring at routine monitoring sites, testing
for such things as wastewater discharge, runoff from quarry operations,
accidental spills, ammonia excreted by animals or from fertilizers, and
agricultural runoff, among many other things (Nueces River Authority
2010, pp. 2-3). If water quality issues are detected, the Nueces River
Authority and TCEQ may take appropriate corrective actions.
Lastly, the TPWD recognized the upper reaches of the West Nueces,
Nueces, Frio, and Sabinal Rivers as ecologically significant river and
stream
[[Page 48784]]
segments (Norris et al. 2005, p. 3). Designation of a stream segment as
ecologically unique offers a certain degree of protection from
activities such as reservoir construction (Norris et al. 2005, p. 5).
This designation does not impart protection from degradation, but
rather prohibits a State agency or political subdivision of the State
from financing the actual construction of a reservoir in a specific
river or stream segment designated as ecologically significant by the
legislature under section 16.051(f) of the Texas Water Code (Norris et
al. 2005, p. 4).
Summary of Factor D
In conclusion, there are Federal and State regulatory protections
currently in place offering some levels of protection for the Nueces
River shiner from such factors as degraded water quality, pollution,
and reservoir construction. However, as discussed in other Factors of
the Nueces River shiner, we have not identified any threats to the
species that are likely to negatively affect the status of the species
such that an inadequacy of existing regulatory mechanisms is likely to
be a threat to the species. Therefore, we find that the Nueces River
shiner is not in danger of extinction now or in the foreseeable future
as a result of inadequacy of existing regulatory mechanisms.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Global climate change, and associated effects on regional climatic
regimes, is not well understood, but model predictions are that
temperatures in the southwestern United States will continue to
increase, with extreme weather events (such as heat waves, drought, and
flooding) occurring with more frequency (Archer and Predick 2008, p.
24). Also, there is some scientific information suggesting that fish in
streams in southwestern North America may be vulnerable to extirpation
or extinction due to global climate change because many fish species
are already living near their lethal thermal limits (Mathews and
Zimmerman 1990, p. 26). Endemic species, like the Nueces River shiner,
which only inhabits the spring-fed headwaters of the Nueces River,
could be more vulnerable to rising stream temperatures because they may
not be able to move to more suitable areas. On the other hand, spring-
fed streams have nearly constant environmental conditions, such as
temperature, due to the constancy of groundwater chemistry and
discharge (Hoagstrom et al. 2011, p. 22). Thus, areas with substantial
connections to aquifers may sustain endemic fishes because groundwater
responds slowly to climate change, buffering against fluctuations in
climate conditions (Hoagstrom et al. 2011, p. 22). Additionally, we are
not aware of any research that has been conducted on water temperature
tolerance of the Nueces River shiner. Because the Nueces River shiner's
water temperature tolerance is unknown, the point at which rising
stream temperatures may impact the species is also unknown.
Likewise, recent models on climate change have indicated that
annual mean precipitation in the southwestern United States is likely
to decrease (Intergovernmental Panel on Climate Change (IPCC) 2007, p.
887). Decreased precipitation could result in diminished water flows,
which may cause losses in habitat diversity, reduce stream
productivity, and degrade water quality (Norris et al. 2005, p. 1).
While it appears reasonable to assume that climate change could affect
the Nueces River shiner by reduced water flows, we lack sufficient
certainty to know specifically how climate change will affect the
species. We have not identified, nor are we aware of, any data on an
appropriate scale to evaluate habitat or population trends for the
Nueces River shiner within its range, or to make predictions on future
trends and whether the species will actually be impacted.
There are multiple hypothetical outcomes associated with climate
change that could potentially affect the Nueces River shiner, but we
lack predictive local or regional models on how climate change will
specifically affect the Nueces River shiner or its habitat. Currently,
we have no certainty regarding the timing, magnitude, or effects of
impacts. Therefore, we find at this time that it is not possible to
make reliable predictions of climate change effects on the status of
the Nueces River shiner due to current limitations in available data
and climate models. Based on the best available information and our
current knowledge and understanding, we find that the Nueces River
shiner is not in danger of extinction now or in the foreseeable future
as a result of natural or other manmade threats affecting its continued
existence.
Finding for the Nueces River Shiner
As required by the Act, we considered the five factors in assessing
whether the Nueces River shiner is threatened or endangered throughout
all or a significant portion of its range. We examined the best
scientific and commercial information available regarding the past,
present, and future threats faced by the species. We reviewed the
petition, information available in our files, other available published
and unpublished information, and we consulted with recognized species
experts and State agencies.
In considering what factors might constitute threats, we must look
beyond the mere exposure of the species to the factor to determine
whether the species responds to the factor in a way that causes actual
impacts to the species. If there is exposure to a factor, but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species such that the species warrants
listing as threatened or endangered as those terms are defined by the
Act. This does not necessarily require empirical proof of a threat. The
combination of exposure and some corroborating evidence of how the
species is likely impacted could suffice. The mere identification of
factors that could impact a species negatively is not sufficient to
compel a finding that listing is appropriate; we require evidence that
these factors are operative threats that act on the species to the
point that the species meets the definition of threatened or endangered
under the Act.
Our review of all the available information does not support a
determination that any current activities or activities in the
foreseeable future threaten the Nueces River shiner or its habitat to
the point that the species meets the definition of threatened or
endangered under the Act. There is no evidence indicating that reduced
water flow, improper grazing of livestock, pollution, and land use are
affecting the species or its habitat. Overutilization, disease, and
predation are not known concerns for this species. We find that no
existing regulatory mechanisms are inadequate to limit or prevent
possible negative impacts from human activities. Climate change could
affect the habitat of the Nueces River shiner in the future, but we
have no certainty regarding the timing, magnitude, or effects of
impacts to the species.
Based on our review of the best available scientific and commercial
information pertaining to the five factors, we find that there are no
threats to indicate that the Nueces River shiner is in danger of
extinction (endangered) or likely to become endangered within the
foreseeable future (threatened)
[[Page 48785]]
throughout its range. Therefore, we find that listing the Nueces River
shiner as endangered or threatened is not warranted throughout its
range at this time.
Summary of Information Pertaining to the Five Factors for Plateau
Shiner
The plateau shiner's range is in close proximity to the Nueces
River shiner's range. Subsequently, many of the factors that may affect
the Nueces River shiner also may affect the plateau shiner. Therefore,
much of the information presented in this section is similar to that
presented above for the Nueces River shiner. However, the plateau
shiner does inhabit separate headwaters of the Sabinal and Frio Rivers
in the Edwards Plateau region of Texas, whereas the Nueces River shiner
inhabits the headwaters of the Nueces River. The Sabinal and Frio
Rivers are part of the Nueces River basin because they flow into and
become part of the Nueces River in south-central Texas. Because the
plateau shiner occupies separate headwaters than the Nueces River
shiner, we will discuss any potential threats that might uniquely
affect the plateau shiner, but because these two shiner species occupy
nearby headwaters and are very similar species, we will refer to the
information above, where appropriate.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
The following factors have the potential to affect the habitat or
range of the plateau shiner: Livestock grazing, reduced water quantity,
impaired water quality, and land use. Below, we discuss each of these
factors and determine whether or not they constitute a threat to the
plateau shiner.
Livestock Grazing
While we know that livestock grazing occurs within the range of the
species, we could find no information on the extent or intensity of
historical, current, or future livestock grazing practices or impacts
that grazing may be having on the species. As previously mentioned,
Richardson and Gold (1995, p. 35) cited a personal communication in
their study to conclude that much of the land in the Nueces River basin
was used for agriculture, and that overgrazing by cattle posed serious
problems for aquatic fauna. However, based on the best available
information, we could find no evidence or data to indicate that
improper livestock grazing affects the plateau shiner or its habitat.
Therefore, we find that the plateau shiner is not in danger of
extinction now or in the foreseeable future as a result of livestock
grazing.
Water Quantity
Please see Factor A discussion of the Nueces River shiner for a
more thorough discussion of the potential impacts of reduced water flow
on these fish. As stated above and based on the best available
information, we have no evidence to indicate that reduced stream flow
is occurring within the range of the plateau shiner at a level that may
be impacting the species. As we have noted previously, Edwards et al.
(2008, p. 25) analyzed stream flow measurements in the Frio, Sabinal,
and Nueces Rivers for the last decade and showed that there was a
normal range of flow variation in each of the streams. Therefore, based
on the best available information, we find that the plateau shiner is
not in danger of extinction now or in the foreseeable future as a
result of reduced water flows.
Water Quality
Based on the best available information, there is no evidence that
diminished water quality caused by pollution may be occurring within
the range of the plateau shiner at a level that affects the species or
its habitat. In 2005, the TPWD noted the Frio and Sabinal Rivers as
having high water quality and exceptional aquatic life (Norris et al.
2005, pp. 16, 19). However, water quality tests have been conducted on
other areas where plateau shiners are known to occur, such as the
uppermost reaches of the Sabinal River, and water quality impairment
has been detected (Nueces River Authority 2010, p. 16). Even though a
stream segment in the upper Frio River remains on the State of Texas'
Clean Water Act 303(d) list as impaired and is within the range of the
species, there does not appear to be adverse impacts to the plateau
shiner or its habitat.
In 2000, a 47-mi (76-km) stream segment from where the West Frio
River and the East Frio River flow together in Real County, at a point
110 yards (yd) (100 meters (m)) upstream of Highway 90 in Uvalde
County, was included on the State of Texas' Clean Water Act 303(d) list
as impaired due to concentrations of dissolved oxygen below criteria
associated with exceptional aquatic life (Bonner et al. 2004, pp. 1-3).
The dissolved oxygen criteria was established based on the fact that
organisms that live in water need oxygen to live, and in waters with
depressed dissolved oxygen levels, organisms may not have sufficient
oxygen to survive (Nueces River Authority 2010, p. 3). Following this
designation as impaired in 2000, TCEQ initiated a project to verify the
impairment through the collection of additional physical, chemical, and
biological data (Bonner et al. 2004, p. 3). As a result, Bonner et al.
(2004, p. 1) conducted a 3-year monitoring study of water quality at
several stations along the upper Frio River from 2002 through 2004.
Based upon the 24-hour dissolved oxygen data collected for this study,
Bonner et al. (2004, p. 20) found no impairment due to depressed levels
of dissolved oxygen in the water and concluded that the upper Frio
River was meeting the exceptional aquatic life use standard. Routine
water samples yielded no significant levels of nutrient impairment
(Bonner et al. 2004, p. 20). Therefore, Bonner et al. (2004, p. 1)
recommended removing the upper Frio River from the State's list of
impaired waters.
As part of the impairment verification monitoring project on this
47-mi (76-km) stream segment in the upper Frio River, Ecological
Communications Corporation conducted biological data collection and
analysis in September 2002, August 2003, and October 2003 (Walther and
Palma 2004, p. 3). Based on the biological and habitat data collected
by Ecological Communications Corporation, it appeared that the number
and diversity of aquatic organisms were lower than the established
standards set forth in the Texas Clean Water Act (Walther and Palma
2004, p. 8).
In 2008 and 2010, this same stream segment of the Frio River
continued to remain on the 303(d) list because of concerns for impaired
habitat, fish community, and organisms living at the bottom of the
water (Nueces River Authority 2008, pp. 56-58; Nueces River Authority
2010, p. 17; TCEQ 2010a, p. 86). However, all testing resulted in data
that were within TCEQ's normal range, which included dissolved oxygen,
pH, total phosphorus, nitrates, ammonia, chlorophyll-a, nutrients, and
bacteria (Nueces River Authority 2008, pp. 56-58; Nueces River
Authority 2010, p. 17). Also, no hypotheses were given for the reasons
this stream segment had aquatic life uses that were lower than
established standards (Nueces River Authority 2008, 2010). Edwards et
al. (2008, p. 29) analyzed the biological integrity of streams in the
upper headwaters of the Nueces River basin, and noted that the water
quality was generally high and the fish fauna present were typical of
high-quality spring-fed streams. Also, Edwards et al. (2008, p. 6)
stated that the plateau shiner was one of the most abundant fishes
surveyed.
[[Page 48786]]
Another stretch of the Frio River, a segment 158 mi (254 km) long,
from 110 yds (100 m) upstream of Highway 90 in Uvalde County to the
confluence with Choke Canyon Reservoir in McMullen County, was placed
on the 303(d) list as impaired for bacteria in 2008 and 2010 (Nueces
River Authority 2008, pp. 66-71; Nueces River Authority 2010, p. 20;
TCEQ 2010a, p. 86). However, this stretch of the Frio River is further
downstream in south-central Texas, outside of the plateau shiner's
range. Therefore, factors affecting this stream segment are not likely
to affect the plateau shiner or its habitat.
As previously noted above under Factor A analysis for the Nueces
River shiner, Edwards et al. (2008, p. 3) conducted a study to find out
if there were potential impacts that may be factors in population and
range declines among native fishes, including the plateau shiner, in
the upper headwaters of the Nueces River basin. Edwards et al. (2008,
p. 27) analyzed the biological integrity of streams in the upper Nueces
River basin, including the Sabinal and Frio Rivers where the plateau
shiner is found. Edwards et al. (2008, p. 27) found that the Sabinal
and Frio Rivers had exceptional water quality within the range of the
plateau shiners. Also, Edwards et al. (2008, p. 29) noted that the
water quality was generally high and the fish fauna present were
typical of high-quality spring-fed streams within the southern Edwards
Plateau. On the other hand, Edwards et al. (2008, p. 29) noted a number
of significant impacts, such as development along the watercourse, low-
head dams along the Sabinal River, and at times intense recreational
pressures during the summer months, especially along the Frio River.
Even with these impacts to the streams, the headwaters of the Sabinal
and Frio Rivers maintained much of their integrity as evidenced by the
numerous indicator fishes (fishes thought to be sensitive to, and serve
as an early warning indicator of, environmental changes), such as the
plateau shiner (Edwards et al. 2008, p. 27). In fact, Edwards et al.
(2008, p. 6) stated that the plateau shiner was one of the most
abundant fishes. Because the plateau shiner was one of the most
abundant species surveyed, it does not appear that factors related to
development along the watercourse, low-head dams, and recreational use
are negatively impacting the plateau shiner.
In conclusion, even though a portion of the Frio River is listed as
impaired by the State of Texas under the Clean Water Act 303(d) because
of concerns for impaired habitat, fish community, and organisms living
at the bottom of the water, a study conducted by Edwards et al. (2008)
found no evidence of actual impacts on the plateau shiner. Likewise,
Bonner et al. (2004, p. 20) previously found no impairment due to
depressed levels of dissolved oxygen in the water and concluded that
the upper Frio River was meeting the exceptional aquatic life use
standard. In addition, all water quality monitoring in the impaired
stream segment resulted in water parameters within the normal range
(Nueces River Authority 2008, pp. 56-58; Nueces River Authority 2010,
p. 17). Based on the best available information, we find that the
plateau shiner is not in danger of extinction now or in the foreseeable
future as a result of degraded water quality.
Land Use
The primary land use factors that could affect the plateau shiner
are recreation, agricultural activities, and land development. The
upper Frio River is used extensively for recreation, and the extensive
recreational usage is expected to continue in the future (Walther and
Palma 2004, p. 1; Nueces River Authority 1998, p. 2). Although we could
find no evidence to indicate that recreational usage may be impacting
plateau shiner in the Sabinal River, it is reasonable to assume that
recreational use does occur in this river. The Frio River is very
popular for recreational activities such as canoeing, tubing, fishing,
and wildlife viewing (Norris et al. 2005, p. 15). A study was conducted
on the upper Frio River to evaluate the impact of recreational use and
land development on water quality and the aquatic biological community
(Nueces River Authority 1998, p. 2). Impacts were evaluated through the
collection and interpretation of information on land uses and historic
utilization, and by conducting biological assessments, toxicity
testing, and water quality analysis (Nueces River Authority, p. 2). The
Nueces River Authority (1998, p. 3) noted that the upper Frio River was
primarily forest and rangeland with some agricultural activities,
mainly orchards and nurseries, and very limited urban land development,
primarily related to tourist and camping accommodations. Overall, the
chemical and physical water quality of the upper Frio River was found
to be very good, and recreational use had little impact on river
quality during the spring and summer visitation period (Nueces River
Authority 1998, p. 10). This is further supported by an Edwards et al.
(2008, p. 27) study, which found that the Sabinal and Frio Rivers had
exceptional water quality. Based on our review of the best available
information, we find that the plateau shiner is not in danger of
extinction now or in the foreseeable future as a result of recreational
use or any other type of land use.
Summary of Factor A
We relied on the best available scientific and commercial
information, which does not indicate that any of the factors discussed
above are impacting the plateau shiner at a level that constitutes a
threat to the species. Therefore, we find that the plateau shiner is
not in danger of extinction now or in the foreseeable future as a
result of the present or foreseeable destruction, modification, or
curtailment of its habitat or range.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Based on the best available scientific and commercial information,
there is no evidence that impacts are occurring to the plateau shiner
or its habitat under this factor. Other than the scientific studies
referenced in this finding, the plateau shiner is not used for any
commercial, recreational, or educational purposes. Therefore, we find
that the plateau shiner is not in danger of extinction now or in the
foreseeable future as a result of overutilization for commercial,
recreational, scientific, or educational purposes.
Factor C. Disease or Predation
As with the Nueces River shiner, we are not aware of any research
that has been conducted to specifically examine disease or predation in
the plateau shiner. There was no mention of disease or predation in our
review of the best available information. Also, we are not aware of any
nonnative species that may prey on the plateau shiner. Therefore, we
find that the plateau shiner is not in danger of extinction now or in
the foreseeable future as a result of disease or predation.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
As we discussed in more detail above under Factor D analysis for
the Nueces River shiner, there are Federal and State regulatory
protections currently in place offering some levels of protection for
the plateau shiner, particularly from such factors as degraded water
quality, pollution, and reservoir construction. The Factor D analysis
for the Nueces River shiner presented above also pertains to the
plateau shiner's habitat and range. However, as discussed in other
Factors for the plateau shiner, we have not identified any threats to
the
[[Page 48787]]
species that are negatively affecting the status of the species, such
that an inadequacy of regulatory mechanisms is likely to be a threat to
the species. Therefore, we find that the plateau shiner is not in
danger of extinction now or in the foreseeable future as a result of
inadequacy of regulatory mechanisms.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
The same impacts discussed above under the Factor E analysis for
the Nueces River shiner also apply to the plateau shiner. As with the
Nueces River shiner, there are multiple hypothetical outcomes
associated with climate change that could potentially affect the
plateau shiner, but we lack predictive local or regional models on how
climate change will specifically affect the plateau shiner or its
habitat. Currently, we have no certainty regarding the timing,
magnitude, or effects of impacts from climate change. Therefore, we
conclude that at this time it is not possible to make reliable
predictions of climate change effects on the status of the plateau
shiner due to current limitations in available data and climate models.
Based on the best available information, we find that the plateau
shiner is not in danger of extinction now or in the foreseeable future
as a result other natural or manmade factors affecting its continued
existence.
Finding for the Plateau Shiner
As required by the Act, we considered the five factors in assessing
whether the plateau shiner is threatened or endangered throughout all
or a significant portion of its range. We examined the best scientific
and commercial information available regarding the past, present, and
future threats faced by the species. We reviewed the petition,
information available in our files, other available published and
unpublished information, and we consulted with recognized species
experts and State agencies.
In considering what factors might constitute threats, we must look
beyond the mere exposure of the species to the factor to determine
whether the species responds to the factor in a way that causes actual
impacts to the species. If there is exposure to a factor, but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species such that the species warrants
listing as threatened or endangered as those terms are defined by the
Act. This does not necessarily require empirical proof of a threat. The
combination of exposure and some corroborating evidence of how the
species is likely impacted could suffice. The mere identification of
factors that could impact a species negatively is not sufficient to
compel a finding that listing is appropriate; we require evidence that
these factors are operative threats that act on the species to the
point that the species meets the definition of threatened or endangered
under the Act.
Our review of the best available information does not support a
determination that any current activities or activities in the
foreseeable future threaten the plateau shiner or its habitat to the
point that the species meets the definition of threatened or endangered
under the Act. There is no evidence indicating that reduced water flow,
improper grazing by livestock, diminished water quality caused by
pollution, or land use is affecting the species or its habitat.
Overutilization, disease, and predation are not concerns for this
species. We find no existing regulatory mechanisms that are inadequate
to limit or prevent possible negative impacts from human activities.
Climate change is another factor that could affect the habitat of the
plateau shiner in the future, but we have no certainty regarding the
timing, magnitude, or effects of impacts to the species.
Based on our review of the best available scientific and commercial
information pertaining to the five factors, we find that there are no
threats to indicate that the species is in danger of extinction
(endangered), or likely to become endangered within the foreseeable
future (threatened), throughout its range. Therefore, we find that
listing the plateau shiner as a threatened or endangered species is not
warranted throughout its range at this time.
Significant Portion of the Range and Distinct Vertebrate Population
Segments
After assessing whether the two species are threatened or
endangered throughout their ranges, we next consider whether either a
significant portion of the Nueces River and plateau shiners' ranges or
a distinct population segment (DPS) of either or both species meets the
definition of endangered or is likely to become endangered in the
foreseeable future (threatened).
Significant Portion of the Range
Having determined that the Nueces River and plateau shiners do not
meet the definition of a threatened or endangered species throughout
all of their ranges, we must next consider whether there are any
significant portions of the range where either species are in danger of
extinction or is likely to become endangered in the foreseeable future.
The Act defines an endangered species as one ``in danger of
extinction throughout all or a significant portion of its range,'' and
a threatened species as one ``likely to become an endangered species
within the foreseeable future throughout all or a significant portion
of its range.'' The term ``significant portion of its range'' is not
defined by the statute. For the purposes of this finding, a portion of
the species' range is ``significant'' if it is part of the current
range of the species, and it provides a crucial contribution to the
representation, resiliency, or redundancy of the species. For the
contribution to be crucial it must be at a level such that, without
that portion, the species would be in danger of extinction.
In determining whether a species is threatened or endangered in a
significant portion of its range, we first identify any portions of the
range of the species that warrant further consideration. The range of a
species can theoretically be divided into portions an infinite number
of ways. However, there is no purpose to analyzing portions of the
range that are not reasonably likely to be significant and threatened
or endangered. To identify only those portions that warrant further
consideration, we determine whether there is substantial information
indicating that: (1) The portions may be significant, and (2) the
species may be in danger of extinction there or likely to become so
within the foreseeable future. In practice, a key part of this analysis
is whether the threats are geographically concentrated in some way. If
the threats to the species are essentially uniform throughout its
range, no portion is likely to warrant further consideration. Moreover,
if any concentration of threats applies only to portions of the
species' range that clearly would not meet the biologically based
definition of ``significant'' (i.e., the loss of that portion clearly
would not reasonably be expected to increase the vulnerability to
extinction of the entire species to the point that the species would
then be in danger of extinction), such portions will not warrant
further consideration.
[[Page 48788]]
If we identify portions that warrant further consideration, we then
determine whether the species is threatened or endangered in these
portions of its range. Depending on the biology of the species, its
range, and the threats it faces, it might be more efficient for us to
address either the ``significant'' question first, or the status
question first. Thus, if we determine that a portion of the range is
not ``significant,'' we do not need to determine whether the species is
in endangered or threatened there; if we determine that the species is
not endangered or threatened in a portion of its range, we do not need
to determine if that portion is ``significant.''
Applying the process described above for determining whether a
species is threatened or endangered in a significant portion of its
range, we consider status first to determine if any threats or
potential threats acting individually or collectively threaten or
endanger the species in a portion of its range. We have analyzed the
threats to the degree possible, and determined they are essentially
uniform throughout both species' ranges.
There is no information to suggest that any portion of the ranges
of either species contributes more significantly to species than any
other portion of their ranges. There is no information to suggest that
any portion of their ranges is of better quality than any other
portion, or that any portion includes important concentrations of
certain types of habitat that are necessary for the species to carry
out its life-history functions. As a result, we conclude that there is
no information that a particular portion of the Nueces River or plateau
shiners' range warrants further consideration as threatened or
endangered.
Conclusion of 12-Month Finding
We do not find the Nueces River shiner or plateau shiner to be in
danger of extinction now, nor is either species likely to become
endangered within the foreseeable future throughout all or a
significant portion of their range. Therefore, listing either species
as threatened or endangered under the Act is not warranted at this
time.
We request that you submit any new information concerning the
status of, or threats to, the species to our Austin Ecological Services
Field Office (see ADDRESSES section) whenever it becomes available. New
information will help us monitor the Nueces River and plateau shiners
and encourage their conservation. If an emergency situation develops
for the Nueces River shiner, plateau shiner, or any other species, we
will act to provide immediate protection.
Distinct Vertebrate Population Segment
Under the Service's Policy Regarding the Recognition of Distinct
Vertebrate Population Segments Under the Endangered Species Act (61 FR
4722, February 7, 1996), three elements are considered in the decision
concerning the establishment and classification of a possible DPS.
These are applied similarly for additions to or removal from the
Federal List of Endangered and Threatened Wildlife. These elements
include:
(1) The discreteness of a population in relation to the remainder
of the species to which it belongs;
(2) The significance of the population segment to the species to
which it belongs; and
(3) The population segment's conservation status in relation to the
Act's standards for listing, delisting, or reclassification (i.e., is
the population segment endangered or threatened).
Discreteness
Under the DPS policy, a population segment of a vertebrate taxon
may be considered discrete if it satisfies either one of the following
conditions:
(1) It is markedly separated from other populations of the same
taxon as a consequence of physical, physiological, ecological, or
behavioral factors. Quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation.
(2) It is delimited by international governmental boundaries within
which differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act.
We determine, based on a review of the best available information,
that neither the Nueces River shiner nor the plateau shiner meet the
discreteness conditions of the 1996 DPS policy. Neither species has
populations that are known to be markedly separate from other
populations of the same taxon, nor does either species have populations
delimited by international governmental boundaries. Therefore, these
population segments do not qualify as a DPS under our policy and are
not listable entities under the Act.
The DPS policy is clear that significance is analyzed only when a
population segment has been identified as discrete. Because no
population segment met the discreteness element for either the Nueces
River or plateau shiners, neither species qualifies as a DPS under the
Service's DPS policy. Therefore, we will not conduct an evaluation of
significance.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Austin Ecological
Services Field Office (see ADDRESSES section).
Authors
The primary authors of this notice are staff members of the
Southwest Regional Office.
Authority: The authority for this section is section 4 of the
Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: July 27, 2011.
James J. Slack,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2011-20054 Filed 8-8-11; 8:45 am]
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