[Federal Register Volume 77, Number 108 (Tuesday, June 5, 2012)]
[Proposed Rules]
[Pages 33143-33155]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-13320]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R6-ES-2012-0023; 4500030114]
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
a Petition To List the Southern White-Tailed Ptarmigan and the Mt.
Rainier White-Tailed Ptarmigan as Threatened With Critical Habitat
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding and initiation of status
review.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day finding on a petition to list the southern white-tailed
ptarmigan (Lagopus leucura altipetens) and the Mt. Rainier white-tailed
ptarmigan (L. l. rainierensis) as threatened under the Endangered
Species Act of 1973, as amended (Act), and designate critical habitat.
Based on our review, we find that the petition presents substantial
scientific or commercial information indicating that listing the
southern white-tailed ptarmigan and the Mt. Rainier white-tailed
ptarmigan may be warranted. Therefore, with the publication of this
notice, we are initiating a review of the status of the two subspecies
to determine if listing is warranted. To ensure that this status review
is comprehensive, we are requesting scientific and commercial data and
other information regarding these subspecies. Based on the status
review, we will issue a 12-month finding on the petition, which will
address whether the petitioned action is warranted, as provided in
section 4(b)(3)(B) of the Act. We will make a determination on critical
habitat for these subspecies if and when we initiate a listing action.
DATES: To allow us adequate time to conduct this review, we request
that we receive information on or before August 6, 2012. The deadline
for submitting an electronic comment using the Federal eRulemaking
Portal (see ADDRESSES section, below) is 11:59 p.m. Eastern Time on
this date. After August 6, 2012, you must submit information directly
to the Colorado Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT section, below). Please note that we might not be
able to address or incorporate information that we receive after the
above requested date.
ADDRESSES: You may submit information by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the SEARCH field, enter Docket No. FWS-R6-ES-
2012-0023, which is the docket number for this action. Then click on
the Search button. You may submit a comment by clicking on ``Submit a
Comment.''
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R6-ES-2012-0023; Division of Policy and
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax
Drive, MS 2042-PDM; Arlington, VA 22203.
We will not accept email or faxes. We will post all information we
receive on http://www.regulations.gov. This generally means that we
will post any personal information you provide us (see the Request for
Information section below for more details).
FOR FURTHER INFORMATION CONTACT: Susan Linner, Field Supervisor, U.S.
Fish and Wildlife Service, Colorado Ecological Services Field Office,
P.O. Box 25486, DFC Mail Stop 65412, Denver, CO 80225-0486; telephone
(303) 236-4773; fax (303) 236-4005. If you use a telecommunications
device for the deaf (TDD), please call the Federal Information Relay
Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Request for Information
When we make a finding that a petition presents substantial
information indicating that listing a species may be warranted, we are
required to promptly review the status of the species (status review).
For the status review to be complete and based on the best available
scientific and
[[Page 33144]]
commercial information, we request information on the southern white-
tailed ptarmigan and the Mt. Rainier white-tailed ptarmigan from
governmental agencies, Native American tribes, the scientific
community, industry, and any other interested parties. We particularly
seek the following information regarding the southern and Mt. Rainier
white-tailed ptarmigans:
(1) Biology, range, and population trends, including:
(a) Taxonomy (especially the genetics of the species and
subspecies);
(b) Historic and current range, including distribution patterns;
and
(c) Historic and current population levels, and current and
projected trends.
(2) Past and ongoing conservation measures and management programs
for the species, its habitat, or both.
(3) The potential effects of climate change on habitats.
We also seek information on the following five threat factors used
to determine if a species, as defined by the Act, is endangered or
threatened under section 4(a) of the Act (16 U.S.C. 1531 et seq.):
(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.
Of particular interest to us is information on the potential
cumulative effects of the five threat factors listed above.
If, after the status review, we determine that listing the southern
or Mt. Rainier white-tailed ptarmigan is warranted, we will propose
critical habitat (see definition in section 3(5)(A) of the Act), in
accordance with section 4 of the Act, to the maximum extent prudent and
determinable at the time we propose to list the species. Therefore, we
also request data and information on:
(1) What may constitute ``physical or biological features essential
to the conservation of the species,'' within the geographical range
currently occupied by the species.
(2) Where these features are currently found.
(3) Whether any of these features may require special management
considerations or protection.
(4) Specific areas outside the geographical area occupied by the
species that are ``essential for the conservation of the species.''
(5) What, if any, critical habitat you think we should propose for
designation if the species is proposed for listing, and why such
habitat meets the requirements of section 4 of the Act.
We will base our 12-month finding on a review of the best
scientific and commercial information available, including all
information we receive during this public comment period. Please
include sufficient information with your submission (such as scientific
journal articles or other publications) to allow us to verify any
scientific or commercial information you include.
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. Section
4(b)(1)(A) of the Act directs that determinations as to whether any
species is an endangered or threatened species must be made ``solely on
the basis of the best scientific and commercial data available.'' At
the conclusion of the status review, we will issue a 12-month finding
on the petition, as provided in section 4(b)(3)(B) of the Act.
You may submit your information concerning this status review by
one of the methods listed 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 personal identifying 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.
Information and supporting documentation that we received and used
in preparing this 90-day finding are available for you to review at
http://www.regulations.gov, or by appointment, during normal business
hours, at the U.S. Fish and Wildlife Service, Colorado Ecological
Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Background
Section 4(b)(3)(A) of the Act requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted. We are to base this finding on
information provided in the petition, supporting information submitted
with the petition, and information otherwise available in our files. To
the maximum extent practicable, we are to make this finding within 90
days of our receipt of the petition, and publish our notice of the
finding promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly conduct a species status review, which we subsequently
summarize in our 12-month finding.
Petition History
On August 24, 2010, we received a petition of the same date
prepared by Noah Greenwald for the Center for Biological Diversity
(petitioner) requesting that we list either the U.S. population or the
Rocky Mountains population of the white-tailed ptarmigan (Lagopus
leucura) as threatened and to designate critical habitat. The petition
clearly identified itself as such and included the requisite
identification information for the petitioner, as required by 50 CFR
424.14(a). The petition specifically requested that we list either the
contiguous U.S. population of white-tailed ptarmigan as a distinct
population segment or list only the Rocky Mountain population as a
distinct population segment under the Act. On May 6, 2011, we notified
the petitioner that we received the petition and requested copies of
the references cited.
In a July 20, 2011, letter we informed the petitioner that we had
reviewed the information presented in the petition and determined that
each of the requested distinct population segments included multiple,
recognized subspecies of white-tailed ptarmigan. Therefore, we could
not accurately evaluate the discreetness and significance criteria for
the two requested population segments according to our Policy Regarding
the Recognition of Distinct Vertebrate Population Segments Under the
Endangered Species Act (61 FR 4722; February 7, 1996). Our letter
provided the petitioner with an opportunity to amend or revise the
petition based on our acceptance of the subspecific taxonomic
designations of white-tailed ptarmigan.
On September 1, 2011, the petitioner responded by email and
indicated that they intended to revise their petition
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based on the information that we provided in our July 20 letter. In a
letter dated October 12, 2011, the petitioner revised their petition to
request listing of the southern white-tailed ptarmigan and the Mt.
Rainier white-tailed ptarmigan as threatened. We verified receipt of
the revised petition by email on October 12, 2011. This finding
addresses the revised petition.
Previous Federal Actions
There are no previous Federal actions involving the white-tailed
ptarmigan or any of the subspecies.
Species Information
Taxonomy
The white-tailed ptarmigan is a small bird in the order
Galliformes, family Phasianidae, and the subfamily Tetraoninae, which
includes the grouse, or ground-feeding game birds (Hoffman 2006, p. 11;
NatureServe 2011, p. 1). Likely descended from ancestral rock ptarmigan
(Lagopus muta) isolated during the last ice age (Pleistocene Epoch, 2.6
million to 12,000 years before present), the white-tailed ptarmigan
does not hybridize or compete for resources with either the rock or
willow ptarmigan (L. lagopus) where ranges overlap in the northern part
of the range (Short 1967, p. 17; Johnsgard 1973, p. 252; Gibbard and
van Kolfschoten 2004, p. 441; Hoffman 2006, pp. 11, 36). The blue
grouse (Dendragapus obscurus) shares breeding habitats with the white-
tailed ptarmigan, but hybridization or competition between the species
has not been documented (Hoffman 2006, pp. 11, 36).
There are five recognized subspecies of white-tailed ptarmigan in
North America (American Ornithologists' Union (AOU) 1957, p. 135). The
southern white-tailed ptarmigan (Lagopus leucura altipetens) occupies
the Rocky Mountains in Colorado, New Mexico, and historically in
Wyoming. The Mt. Rainier white-tailed ptarmigan (L. l. rainierensis)
occupies the Cascade Mountains of Washington. The Kenai white-tailed
ptarmigan (L. l. peninsularis) extends from Canada into Alaska, and the
Vancouver white-tailed ptarmigan (L. l. saxatilis) is restricted to
Vancouver Island in Canada. The northern white-tailed ptarmigan (L. l.
leucurus) extends from Canada into Montana (Aldrich 1963, p. 542).
Based on a lack of comparative work, Braun et al. (1993, p. 1)
questioned the status and validity of the five subspecies of white-
tailed ptarmigan. After examining museum specimens, Braun et al.
suggested that the southern, Mt. Rainier, and Vancouver white-tailed
ptarmigans are similar in size and color, whereas the northern and
Kenai white-tailed ptarmigan are similar in size and color (1993, p. 1;
Hoffman 2006, p. 11). Braun et al. observed a gradation in size and
color from south to north, with larger, darker-colored birds in the
south (1993, p. 1). However, Braun et al. never published their
results, and, thus, their questioning of the subspecies designations
has not been subjected to scientific peer review.
Multiple taxonomic authorities for birds recognize the validity of
the five subspecies of white-tailed ptarmigan. The AOU recognized the
five subspecies in their Checklist (1957, p. 135). Since 1957, the AOU
has not conducted a review of its subspecific distinction and stopped
listing subspecies as of the 6th edition in 1983. However, the AOU
recommends the continued use of its 5th edition for taxonomy at the
subspecific level (1997, p. xii). Based on their 1957 consideration of
the taxon, the AOU still recognizes the southern and Mt. Rainier white-
tailed ptarmigan as valid subspecies. Additionally, the Integrated
Taxonomic Information System (ITIS) (2011) and Clements Checklist
(2011, Version 6.6) also recognize the five subspecies of white-tailed
ptarmigan. Hoffman (2006, p. 11) and Storch (2007, p. 39) also
reference the five subspecies. No scientifically peer-reviewed studies
exist that review or analyze the subspecific designations of white-
tailed ptarmigan.
We recognize the lack of information, particularly morphological
and genetic data, regarding the subspecific designations of white-
tailed ptarmigan. We are aware of a proposed study by the U.S.
Geological Survey that will use genetics to clarify the subspecific
designations of white-tailed ptarmigan throughout its range. However,
at the time of this evaluation, the best available scientific and
commercial information suggests that the five subspecies identified by
the AOU are valid. Therefore, we accept the taxonomic characterization
of white-tailed ptarmigan as five subspecies occurring in North
America.
The petitioner requests that we list two of the five recognized
subspecies of white-tailed ptarmigan as threatened: The southern white-
tailed ptarmigan and the Mt. Rainier white-tailed ptarmigan. Section
3(16) of the Act defines the term ``species'' as any subspecies of fish
or wildlife or plants, and any distinct population segment of any
species of vertebrate fish or wildlife which interbreeds when mature.
After a review of the available taxonomic information, we determine
that the southern white-tailed ptarmigan and Mt. Rainier white-tailed
ptarmigan are subspecies and are listable entities under the Act.
During our status review, we will further evaluate the taxonomic
classifications of the southern white-tailed ptarmigan and the Mt.
Rainier white-tailed ptarmigan.
Physical Description
The southern and Mt. Rainier white-tailed ptarmigans are physically
similar (Braun et al. 1993, p. 1; Hoffman 2006, p. 11). Both subspecies
of white-tailed ptarmigan are white in winter and brown in summer, the
feathers changing color with the seasons to camouflage the birds (Braun
et al. 1993, p. 1). Although the body feathers change color, the white-
tailed ptarmigan is named for its white tail feathers, which never
change color. These perpetually white tail feathers distinguish the
species from other ptarmigan species (Short 1967, p. 17; Braun et al.
1993, p. 1; Hoffman 2006, p. 12). Males and females share similar body
size, shape, and winter plumage, with adult body lengths up to 13.4
inches (34 centimeters) and body masses up to 0.9 pounds (425 grams)
(Braun et al. 1993, p. 1; Hoffman 2006, p. 12). During the winter, both
males and females are stark white and difficult to distinguish from
each other and from the background of snow, except for black eyes,
black toenails, and a black beak (Braun et al. 1993, p. 1; Hoffman
2006, p. 12). As the snow melts and the breeding season begins, males
turn a lighter color of brown or gray than females, and have a dark
band of feathers on the breast that resembles a necklace (Braun et al.
1993, p. 1). Both males and females have heavily feathered feet that
act as snowshoes to support them as they walk across the snow (Braun et
al. 1993, p. 1).
Life History
The southern and Mt. Rainier white-tailed ptarmigans share similar
life histories. During the winter, the southern and Mt. Rainier white-
tailed ptarmigans congregate in flocks and travel to the lowest
elevations in their respective ranges, seeking areas with soft snow and
willows (Salix spp.) (Hoffman and Braun 1977, p. 110). During the
winter, the birds feed on willows that protrude through the snow, and
dig burrows, or roosts, in the soft snow that provide shelter from
winter storms (Braun et al. 1993, p. 1; Hoffman 2006, pp. 17, 27). As
alpine winters transition to spring, the southern and Mt. Rainier
white-tailed ptarmigans migrate upwards in elevation for breeding and
nesting to areas that are free of snow and provide access to
[[Page 33146]]
willows by mid-May (Hoffman and Braun 1975, p. 486). After breeding and
nesting, the southern and Mt. Rainier white-tailed ptarmigans spend the
summer at the highest elevations of their respective ranges, where
temperatures are coolest and rocky areas provide protection from
predators and storms. Summer forage includes willows and other plants
(May and Braun 1972, p. 1184; Braun et al. 1993, p. 1; Hoffman 2006, p.
27). The first snowstorm of the season forces the southern and Mt.
Rainier white-tailed ptarmigans back down to the lower elevations of
their respective ranges.
The southern and Mt. Rainier white-tailed ptarmigans spend their
entire lifecycles in alpine ecosystems and are well adapted to survive
in cold, arid, and open alpine environments (Johnson 1968, p. 1011;
Hoffman 2006, p. 12; Storch 2007, p. 4). The color-changing plumage
effectively camouflages the southern and Mt. Rainier white-tailed
ptarmigans against white snow in winter and alpine vegetation and rocks
in the summer (Ligon 1961, p. 87; Braun et al. 1993, p. 1; Martin and
Forbes 2004, p. 1). The color-changing plumage also alters the
reflective and absorptive properties of the feathers according to
season to help the birds regulate body temperature (Hoffman 2006, p.
31). Metabolic rates are low, allowing the southern and Mt. Rainier
white-tailed ptarmigans to gain weight during the winter (Hoffman 2006,
p. 31). Low evaporative efficiencies prevent the loss of body heat
(Laisiewski et al. 1966, p. 15; Johnson 1968, p. 1010; Hoffman 2006, p.
31). Additionally, snowshoe-like, feathered feet allow the southern and
Mt. Rainier ptarmigans to save energy by walking on top of snow rather
than flying, which is energetically expensive (Storch 2007, p. 4).
Habitat
The southern and Mt. Rainier white-tailed ptarmigans inhabit alpine
ecosystems at or above treeline, a transition zone defined as the upper
elevational edge where wind, cold, and harsh weather prevent the growth
of trees (Wardle 1974, p. 371). Treeline occurs at elevations around
11,500 feet (ft) (3,500 meters (m)) above sea level in New Mexico and
southern Colorado, and 9,500 ft (2,900 m) in Wyoming (Hoffman 2006, p.
23). Treeline is as low as 6,600 ft (2,000 m) in the North Cascades of
Washington (Clarke and Johnson 1990, p. 652; Hoffman 2006, p. 23).
These alpine habitats at or above treeline are characterized by high
winds, cold temperatures, short vegetation growing seasons, low
atmospheric oxygen concentrations, and intense solar radiation (Martin
and Weibe 2004, p. 177; Sandercock et al. 2005, p. 13). The extreme
topography and harsh climatic conditions of the alpine slows the growth
of plants (Hoffman 2006, p. 22). Slow growth rates make alpine
ecosystems sensitive to disturbance, and vegetation may take many years
to recover from disturbance (Willard and Marr 1970, p. 257). Within
these open and arid alpine habitats, the southern and Mt. Rainier
white-tailed ptarmigans prefer rocky areas, dwarfed trees, and
vegetation near snowfields and streams (Choate 1963, p. 686; Frederick
and Guti[eacute]rrez 1992, p. 898; Hoffman 2006, p. 23). The southern
and Mt. Rainier white-tailed ptarmigans make seasonal migrations
between elevations. Factors affecting their distribution include cool
temperatures and the presence of exposed rocky areas, soft snow, and
willows (Hoffman 2006, p. 23).
Distribution, Abundance, and Trends
Specific population distribution, abundance, and demography
information is lacking for the white-tailed ptarmigan or any of its
subspecies, likely a reflection of the difficulty of surveying in often
remote, high-elevation habitats. Although, at the species level, the
white-tailed ptarmigan still occupies most of its historical range,
population estimates are mostly unknown, other than in localized areas
of study (Braun et al. 1993, p. 2; Hoffman 2006, p. 16). Storch (2007,
p. 40) estimated a rangewide, spring population of more than 200,000
birds (for all subspecies of white-tailed ptarmigan). The North
American Landbird Conservation Plan estimates the global population at
2,000,000 birds (again, for all subspecies combined) (Rich et al. 2004;
Hoffman 2006, p. 16); however, Hoffman (2006, p. 16) argues that this
estimate is likely extremely inflated and may be a reporting error.
Breeding densities fluctuate between years and locations, ranging from
5 to 36 birds per square mile (sq mi) (2 to 14 birds per square
kilometer (sq km)) (Hoffman 2006, p. 16). Most populations are probably
stable and secure; however, localized populations may be at risk
(Storch 2007, p. 152). NatureServe ranks the white-tailed ptarmigan as
``secure'' rangewide (2011, p. 1). The International Union for
Conservation of Nature (IUCN) ranks the white-tailed ptarmigan as a
species of ``least concern'' (IUCN 2011, p. 1). Within the U.S. Forest
Service (USFS) Rocky Mountain Region, Hoffman states that populations
of white-tailed ptarmigan are stable, and are in no immediate jeopardy
of declining (2006, p. 40). However, these rankings are for the species
as a whole, and do not evaluate the status of the individual subspecies
of the white-tailed ptarmigan.
The white-tailed ptarmigan is endemic to alpine habitats in western
North America and is the only species of ptarmigan whose range extends
south of Canada (Aldrich 1963, p. 543; AOU 1998, p. 120; Hoffman 2006,
p. 12). The southern white-tailed ptarmigan inhabits alpine areas in
the Rocky Mountains of Colorado and New Mexico, but is likely not found
in Wyoming (Hoffman 2006, p. 13). The Mt. Rainier white-tailed
ptarmigan inhabits the northern Cascade Mountains of Washington, but
there are no published accounts of the Mt. Rainier white-tailed
ptarmigan in the Olympic Mountains in the northwestern part of the
State (Hoffman 2006, p. 12). There are no verified records of white-
tailed ptarmigan in Idaho, Oregon, California, or Utah (Gabrielson and
Jewett 1940, p. 602; Aldrich 1963, pp. 541, 543; Braun et al. 1993, p.
1; Gilligan et al. 1994, p. 86; Hoffman 2006, p. 12). The historical
absence of white-tailed ptarmigan from apparently suitable alpine
habitats in Oregon, California, Utah, and the Olympic Mountains in
Washington is due to long distances to the nearest occupied ranges
(Hoffman 2006, p. 12). A lack of suitable alpine habitats explains the
absence of ptarmigan in Idaho (Hoffman 2006, p. 12).
In Colorado, the southern white-tailed ptarmigan lives in all
available alpine areas, except in the Spanish Peaks and Greenhorn
Mountain in the southern part of the State (Braun et al. 1993, p. 1).
Colorado supports the largest population of white-tailed ptarmigan in
the United States outside of Alaska, with a statewide breeding
population estimated at 34,800 birds (Hoffman 2006, pp. 15, 16). At
Rocky Mountain National Park (RMNP) and Mt. Evans in Colorado, Braun et
al. (1993, p. 1) reported breeding densities of 11.7 to 35.0 birds per
sq mi (4.5 to 13.5 birds per sq km) and 5.2 to 26.7 birds per sq mi
(2.0 to 10.3 birds per sq km), respectively (Hoffman 2006, p. 11).
In New Mexico, the southern white-tailed ptarmigan historically
inhabited all the ridges and peaks above timberline within the Sangre
de Cristo Mountains, but by the mid-1900s, it was found only on the
northernmost peaks (Ligon 1961, p. 87; New Mexico Department of Game
and Fish (NMDGF) 2008, p. 87). Following declines in the southernmost
peaks, the NMDGF listed the white-tailed ptarmigan as endangered in
1975 (NMGFD 2008, p. 87). Recent observations and reports
[[Page 33147]]
suggest that the reintroduction of white-tailed ptarmigan into the
southern peaks of the Sangre de Cristo Mountains was successful, and
that populations have persisted on the northernmost peaks (NMDGF 2008,
p. 87). Coordinated surveys of all suitable habitats within the Sangre
de Cristo Mountains are needed to document the current distribution and
abundance of white-tailed ptarmigan in New Mexico (NMDGF 2008, p. 88).
The southern white-tailed ptarmigan appears to be absent from most
alpine habitats in Wyoming, except possibly for the Snowy Range in the
southern part of the State (Hoffman 2006, p. 15). Anecdotal reports
suggest the southern white-tailed ptarmigan persists in the Snowy
Range, but there have been no confirmed sightings since the early 1970s
and the available habitats are limited (Hoffman 2006, p. 15). The
Medicine Bow National Forest in southern Wyoming considers the white-
tailed ptarmigan to be present historically but currently extirpated
from the Snowy Range (USFS 2003, pp. 3, 154; Hoffman 2006, p. 15).
There is little information available regarding the distribution,
abundance, or trends of the Mt. Rainier white-tailed ptarmigan in the
Cascade Mountains of Washington (Smith et al. 1997, p. 140). No studies
have been conducted in Washington other than general monitoring and
surveys to determine presence or absence (Hoffman 2006, p. 8). There
are no population estimates and no published accounts for the white-
tailed ptarmigan in the Olympic Mountains of northwestern Washington
(Hoffman 2006, p. 12). The Mt. Rainier white-tailed ptarmigan inhabits
the North Cascades but not the South Cascades, primarily due to the
lack of suitable alpine areas for dispersal and colonization in the
south (Clark and Johnson 1990, p. 652).
Researchers successfully translocated white-tailed ptarmigan in the
Sierra Nevada Mountains of California, the Uinta Mountains in Utah,
Pike's Peak in Colorado, and the Pecos Wilderness in New Mexico (Braun
et al. 1993, p. 1; Hoffman 2006, p. 13). Reports indicate that
ptarmigans still exist in these translocation areas (Braun et al. 1978,
p. 665; NMDGF 2006, p. 79; Hoffman 2006, p. 13). However, a
translocation attempt in the Wallowa Mountains in northeastern Oregon
was unsuccessful when the introduced population did not survive (Braun
et al. 1993, p. 1; Marshall et al. 2003, p. 618; Hoffman 2006, p. 13).
Evaluation of Information for This Finding
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 a
species to, or removing a species from, the Federal Lists of Endangered
and Threatened Wildlife and Plants. A species may be determined to be
an endangered or threatened species due to one or more of the five
factors described in section 4(a)(1) of the Act:
(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 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 may meet the
definition of endangered or threatened under 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 may not be sufficient to compel a
substantial finding. The information shall contain evidence sufficient
to suggest that these factors may be operative threats that act on the
species to the point that the species may meet the definition of
endangered or threatened under the Act.
In making this 90-day finding, we evaluated whether information
regarding threats to the southern white-tailed ptarmigan and the Mt.
Rainier white-tailed ptarmigan, as presented in the petition and other
information available in our files, is substantial, thereby indicating
that the petitioned action may be warranted. Our evaluation of this
information is presented below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The petitioner asserts that threats causing the present or
threatened destruction, modification, or curtailment of habitat or
range for the southern and Mt. Rainier white-tailed ptarmigans include
global climate change, recreation, livestock grazing, and mining. These
assertions are described in more detail below.
Global Climate Change
Information Provided in the Petition--The petitioner asserts that
global climate change is the greatest threat to the survival of the
southern and Mt. Rainier white-tailed ptarmigans in the United States.
The petitioner claims that the white-tailed ptarmigan depends on open
alpine habitats, willow as its main food source, soft snow in which to
burrow, and cool temperatures to which it is uniquely adapted. The
petitioner also asserts that these subspecies are physiologically
underequipped to cope with rising temperatures associated with global
climate change. Because these are physiological effects rather than
effects to habitat, we discuss these assertions under Factor E.
The petitioner asserts that the loss of alpine habitats to global
climate change threatens the southern and Mt. Rainier white-tailed
ptarmigans, and provides several citations to support these claims.
Foremost amongst these are the various publications of the
Intergovernmental Panel on Climate Change (IPCC), specifically the
four-volume IPCC Fourth Assessment Report: Climate Change 2007 and the
Copenhagen Diagnosis, 2009: Updating the World on the Latest Climate
Science (IPCC 2007, p. iii; 2009, p. 1). The Copenhagen Diagnosis
summarizes research regarding the accumulation of carbon dioxide in the
atmosphere and the resulting greenhouse effect that contributes to
global warming. The IPCC also summarized changes in the amount,
intensity, frequency, and type of precipitation associated with warming
global temperatures (Trenberth et al. 2007, p. 262).
The petitioner alleges that several of the effects of climate
change threaten the white-tailed ptarmigan. The petition presents
research indicating that mountaintops and their alpine ecosystems are
especially sensitive to changes in climate (Hougton et al. 1995 and
1996; Pepin 2000, p. 135; Beniston et al. 1997, p. 233; Kullman 2002,
p. 68). The petitioner presents research indicating that the greater
photosynthetic efficiency of alpine
[[Page 33148]]
plants coupled with more carbon dioxide in the atmosphere suggests that
overall changes in vegetation will be especially dramatic in alpine
habitats (Korner and Diemer 1994, p. 58; Hoffman 2006, p. 46).
Additionally, warming temperatures will shift treelines upwards in
elevation, reducing available alpine habitats (Markham et al. 1993, p.
65; Root et al. 2003, p. 57; Hoffman 2006, pp. 3, 46). Warmer winter
temperatures also suggest that a higher percentage of total
precipitation will fall as rain rather than snow (Mote 2003, p. 1; Mote
2005, p. 39; Knowles et al. 2006, p. 4545; Karl et al. 2009, pp. 24,
135), which the petitioner argues may further reduce available alpine
habitats for both subspecies.
After summarizing current research on global climate change, the
petitioner provides research that forecasts the range of the white-
tailed ptarmigan under several, predicted climate scenarios (Lawler et
al. 2009, pp. 591-593). The petitioner predicts that the current
northern range of the white-tailed ptarmigan will contract, and the
species will be eliminated from the contiguous United States by year
2061, citing Lawler et al. (2009, appendix e) to support this claim.
Furthermore, the petitioner claims that climate change has already
occurred and is predicted to continue within the range of the southern
and Mt. Rainier white-tailed ptarmigans in the United States. The
petitioner summarizes research indicating that temperatures in Colorado
have increased significantly more than the average for the western
United States (Ray et al. 2008, pp. 5, 10, 11, 21, 29). The references
presented by the petitioner indicate that Colorado will experience few
extreme cold months, more extreme warm months, with more consecutive
warm winters (Ray et al. 2008, p. 29). The petitioner also presents
evidence of ongoing climatic warming within the range of the Mt.
Rainier white-tailed ptarmigan in the Cascade Mountains of Washington
(Karl et al. 2009, pp. 135-136).
The petitioner presents research that global climate change,
through increasing temperatures, also will affect the elevation of
treeline, citing studies that document the advancement of treeline
upslope (Wang et al. 2002b, p. 82; Grace et al. 2002, p. 540; Millar et
al. 2004, p. 181; Stohlgren and Baron 2003, p. 1; Hoffman 2006, p. 45).
The petitioner deduces that the upslope migration of trees and the
expansion of forest will compress and fragment white-tailed ptarmigan
habitats (Wang et al. 2002b, p. 82; Hoffman 2006, p. 45).
Finally, the petitioner presents research that changes will occur
to the alpine plant communities bounded by the encroaching treeline
because of global climate change (Hoffman 2006, p. 46; Cannone et al.
2007, p. 360). Although the exact changes to vegetation communities are
uncertain, the petitioner reasons that the changes will be significant
to the alpine habitats of the white-tailed ptarmigan. The petitioner
also suggests that changed snowfall patterns will alter and reduce the
availability of vegetation features important to the white-tailed
ptarmigan, such as wet meadows below late-lying snowfields that are
used by females to raise broods (Hoffman 2006, p. 46).
The petitioner concludes that global warming is the greatest threat
to the survival of the white-tailed ptarmigan because of the loss and
fragmentation of alpine habitats, the upslope advancement of treeline,
and other changes to alpine plant communities.
Evaluation of Information in the Petition and Available in Service
Files--Climatic and species models referenced by the petitioner suggest
that the white-tailed ptarmigan may be completely extirpated from its
current range within the United States with more than a 90 percent
model agreement under low and high carbon dioxide emission scenarios
(Lawler et al. 2009, appendix e). Therefore, the petitioner concludes
that global warming modifies and curtails the range of the white-tailed
ptarmigan in the United States, restricting the species to any
remaining alpine habitats in Alaska and Canada, resulting in local
extirpations, and threatening both subspecies. Although the
complexities of modeling often confound the predicted species
distributions and loss of habitats attributed to global climate change,
the information presented by the petition and available in our files
indicates that global climate change may curtail the range of the
southern or Mt. Rainier white-tailed ptarmigan, potentially resulting
in the extirpation of both subspecies from the contiguous United
States.
The petitioner cites information indicating that climatic warming
has occurred within the range of the southern and Mt. Rainier white-
tailed ptarmigans. Over the past 30 years, temperatures in Colorado
increased by 1.9 [deg]F (1.1 [deg]C), twice the average increase for
the entire western United States for the same time period (Ray et al.
2008, pp. 10, 21). Ray et al. expect Colorado to warm by 3.96 [deg]F
(2.2 [deg]C) by 2050, with winter temperatures increasing by 3.06
[deg]F (1.7 [deg]C) (Ray et al. 2008, pp. 5, 11, 29). Summer
temperatures also are expected to increase in Colorado, with predicted
increases of 5.04 [deg]F (2.8 [deg]C) (Ray et al. 2008, p. 29). Climate
models for Washington State project increases in annual average
temperatures of 5.22 [deg]F (2.9 [deg]C) by 2080 (Littell et al. 2009,
pp. 33, 199). This report also illustrated an increase of 1.44 [deg]F
(0.8 [deg]C) for Washington since 1920 (Littell et al. 2009, pp. 39,
199). In the Pacific Northwest, spring snowpack has declined by
approximately 40 percent since the mid-20th century and is consistent
with observed increases in global temperature (Mote 2003, p. 2). Payne
et al. (2004, p. 243) predict further declines in the spring snowpack
of the Cascade Mountains by as much as 40 percent by the year 2040.
These studies indicate that temperatures are increasing, and may be a
result of global climate change within the range of the southern and
Mt. Rainier white-tailed ptarmigans.
Furthermore, we evaluated the claims and references provided by the
petitioner regarding the response of treeline to warming temperatures
and the potential impact on alpine environments. For certain areas of
the RMNP in Colorado, krummholz (wind-trimmed, low-growing) trees are
moving upslope at an average rate of 3.3 ft (1 m) per 27 years
(Stohlgren and Baron 2003, p. 1). The researchers predicted that at
certain sites, the krummholz could develop into forests in response to
environmental factors, such as temperature and soil moisture. If
unchecked, the researchers predicted that the developing forests would
invade alpine ecosystems, thereby reducing the diversity of understory
plants and habitat for alpine wildlife (Stohlgren and Baron 2003, p.
1). Based on predicted increases in temperature, Grace et al. (2002, p.
540) similarly predicted the advancement of treeline upwards and the
subsequent invasion of trees into alpine meadows. Forest expansion has
occurred to similar alpine habitats in the Arctic and Alaska (Millar et
al. 2004, p. 181). Available studies also suggest that small increments
of 1.8 to 3.6 [deg]F (1 to 2 [deg]C) of warming may result in changes
to the dynamics of vegetation communities in the alpine (Korner and
Diemer 1994, p. 58; Hoffman 2006, p. 46; Cannone et al. 2007, p. 360).
The response of plants to increased levels of atmospheric carbon
dioxide and shifts in precipitation patterns may impact the
distribution of willow and other important ptarmigan food plants
(Hoffman 2006, p. 46).
Although it is unclear exactly how alpine vegetation communities
will respond to a warming climate, the cited references indicate that
the upslope
[[Page 33149]]
migration of treeline, the expansion of subalpine forests, and changes
to alpine plant communities may occur. Cumulatively, these changes may
reduce the alpine habitats available to the southern and Mt. Rainier
white-tailed ptarmigans; however, the magnitude of this loss is
undeterminable based on our review of the information in the petition
and in our files.
Based on the results of the empirical studies cited by the
petitioner and information available in our files, along with
predictions of increasing air temperatures, decreasing snow packs, and
predicted changes to white-tailed ptarmigan habitats and distribution
of food plants, we find that the ranges of the southern white-tailed
ptarmigan and the Mt. Rainier white-tailed ptarmigans and the alpine
habitats within these ranges may decrease as a result of global climate
change. Therefore, we find that the petition and information in our
files present substantial information to indicate that the predicted
changes in habitat due to the effects of climate change may be a threat
to the southern white-tailed ptarmigan and the Mt. Rainier white-tailed
ptarmigan. We discuss potential physiological and behavioral effects of
a warming climate under Factor E, below.
Recreation
Information Provided in the Petition--The petitioner asserts that
recreational activities (specifically hiking, off-road vehicle (ORV)
use, and skiing) destroy alpine habitats and directly disturb the
southern and Mt. Rainier white-tailed ptarmigans. The petitioner
provides citations indicating that various recreational activities
occur within alpine habitats and that, in Colorado, these activities
have increased in popularity over time (Hesse 2000, p. 68; Ebersole et
al. 2002, p. 101). The petitioner asserts that these activities can
adversely affect habitats of the southern and Mt. Rainier white-tailed
ptarmigans via: (1) Hikers trampling alpine vegetation; (2) the
erosion, slumping, soil compaction, snow compaction, and vegetation
damage from ORV use, including snowmobiles; and (3) the compaction of
snow and loss of willows by skiers and snowmaking machines at ski
areas. The petitioner provides citations to several sources that
describe the impacts of trampling and ORV use on slow-growing alpine
vegetation (Willard and Marr 1971, p. 257; Lodico 1973, entire;
Ebersole et al. 2002, p. 101; Hoffman 2006, p. 43). The petitioner also
provides one reference that speaks generally to the historical impacts
of recreation on alpine habitats (Brown et al. 1978b, pp. 23-44). The
petitioner cites 27 biological evaluations (BEs) prepared by the USFS
in the Rocky Mountain Region that concluded that recreational projects
may affect individual white-tailed ptarmigan, but would not cause a
trend towards Federal listing, a standard for BEs described by the
USFS's operational manual regarding sensitive species (USFS 2011, p. 3,
5).
The petitioner suggests that hikers may wander off trails, trample
alpine vegetation, and create new trails, with lasting damage to
vegetation occurring (Hoffman 2006, p. 43). The petitioner also asserts
that snowmobiles are especially dangerous to the white-tailed ptarmigan
because they may occasionally collide with and kill the birds.
Additionally, the petitioner stresses that noise and activity
associated with snowmobiles may disturb the birds and cause them to
leave their optimal feeding and roosting sites, exposing the birds to
predation (Hoffman 2006, p. 44).
The petitioner cites Braun et al. (1976, p. 9) to report that
white-tailed ptarmigan exist within ski areas, but to a lesser extent,
because of development. However, the petitioner reasons that skiers
repeatedly displace white-tailed ptarmigans and force them to
unnecessarily expend extra energy. Additionally, the petitioner
suggests that skiers and grooming machines may damage willows while
snowmaking operations may cover any remaining willows, rendering them
inaccessible to the white-tailed ptarmigan. The petitioner argues that
skiers and grooming machines also may compact soft snow and make it
unsuitable for roosting (Hoffman 2006, p. 44). Finally, the petitioner
asserts that the development of ski areas results in habitat loss and
may increase predation, which we discuss below under Factor C.
Evaluation of Information in the Petition and Available in Service
Files--Recreational activities occur within the alpine habitats of the
southern and Mt. Rainier white-tailed ptarmigans. However, the
probability of humans interacting with either subspecies or their
habitats remains relatively low, because the severe environment and low
productivity of the alpine zone have deterred human use and habitation
(Hoffman 2006, p. 41). When recreation occurs in alpine habitats, the
effects of trampling, ORVs, skiing, and other forms of recreation on
slow-growing alpine vegetation are well documented (Willard and Marr
1971, p. 257; Billings 1973, p. 703; Lodico 1973, entire; Ebersole et
al. 2002, p. 101). However, we are unaware of any information to
indicate that recreational activities may be a threat to the habitats
or the range of the southern or Mt. Rainier white-tailed ptarmigan.
Although hikers may trample vegetation, ORVs may erode soils, and
skiers or grooming machines may compact snow or cover willows, the
references cited by the petitioner and available in our files describe
only anecdotal and isolated impacts from recreation to the habitats of
the southern and Mt. Rainier white-tailed ptarmigans. While
recreational use of the alpine habitat has increased over time in
Colorado, the references cited by the petitioner and available in our
files do not indicate recreation is occurring at levels that impact the
habitats or range of the southern and Mt. Rainier white-tailed
ptarmigans. We have no specific information, nor did the petitioner
provide any information, regarding recreational use within the range of
the Mt. Rainier white-tailed ptarmigan in Washington. Furthermore, the
cited references provide no information, and we found no information,
that winter recreational activities compact soft snow to an extent that
impedes the construction of snow roosts or limits the availability of
willows such that the southern or Mt. Rainier white-tailed ptarmigan is
unable to seek shelter or feed during the winter. Similarly, the cited
references provide no information to suggest that the development of
ski areas has destroyed, modified, or curtailed the habitats or range
of either of the petitioned subspecies. We have no information and the
petitioner provided no information regarding ski area development in
Washington and potential impacts to the Mt. Rainier white-tailed
ptarmigan.
Additionally, while recreationists in alpine areas may interact
with and occasionally disturb ptarmigan, the cited references and
information in our files provide only anecdotal evidence of this
interaction or disturbance. The references do not suggest that the
southern and Mt. Rainier white-tailed ptarmigans abandon habitats after
being disturbed or that ORVs kill birds in any scope or scale that
result in population-level impacts. We found no evidence that
ptarmigans abandon sites frequented by motorized vehicles. However,
ptarmigans may temporarily move away if disturbed and are occasionally
killed by collisions (Hoffman 2006, p. 44). The petitioner cites USFS
BEs that concluded that recreation projects may affect the white-tailed
ptarmigan in the Rocky Mountain Region, although these BEs concluded
that the activities would not contribute to loss of viability or lead
to a trend
[[Page 33150]]
towards Federal listing. There is also no evidence that these impacts
actually occurred or represent a threat to the southern white-tailed
ptarmigan. Therefore, we find that the petition and information in our
files do not present substantial scientific or commercial information
to indicate that habitat impacts due to recreational activities may be
a threat to the southern or Mt. Rainier white-tailed ptarmigan.
Livestock and Native Ungulate Grazing
Information Provided in the Petition--The petitioner asserts that
livestock grazing, as well as grazing by overabundant native ungulates,
threatens the southern and Mt. Rainier white-tailed ptarmigans by
impacting habitats and reducing the availability of food. The
petitioner asserts that livestock grazing is the dominant land use
within the range of the southern and Mt. Rainier white-tailed
ptarmigans in the United States and provides references demonstrating
that grazing can affect natural communities by removing vegetation,
adjusting the structure of plant communities, and trampling or
compacting soils (Fleischner 1994, p. 629; Krueper et al. 2003, p. 608;
Hoffman 2006, p. 42). The petitioner also asserts that livestock
grazing changes the availability of water, alters the diversity of
plant species, and disrupts nutrient cycling and community succession;
the petitioner presents references in support of those assertions
(Fleischner 1994, pp. 631-634; Fleischner 2010, p. 242). The petitioner
provides references to indicate that cattle grazing may impact the
breeding success of nesting birds in riparian and forested ecosystems
below treeline (Ammon and Stacey 1997, pp. 7, 11, 12; Walsberg 2005, p.
715).
However, the petitioner recognizes that cattle are poorly adapted
to the alpine habitats of the white-tailed ptarmigan and are not a
major influence on alpine areas (Alexander and Jensen 1959, pp. 680-
689; Thilenius 1975, pp. 15, 28). Where cattle cannot graze, the
petitioner asserts that grazing by sheep has deleterious effects on
alpine ecosystems, including the creation of trails, trampling of
vegetation, and overgrazing, resulting in considerable damage to alpine
habitats (Thilenius 1975, p. 28; Hoffman 2006, p. 42). Extended and
concentrated grazing periods, coupled with the long recovery times of
alpine ecosystems, have had a significant impact on the structure and
function of many alpine areas (Thilenius 1975, p. 15; Hoffman 2006, p.
42). Additionally, sheep feed on many of the same plants as the white-
tailed ptarmigan (Hoffman 2006, p. 42). As a result, the petitioner
concludes that sheep compete with the white-tailed ptarmigan for food
where they overlap.
The petitioner cites 13 BEs prepared by the USFS in the Rocky
Mountain Region that determined that grazing sheep may adversely affect
the white-tailed ptarmigan, but would not lead to a trend towards
Federal listing. Potential effects analyzed in the BEs included sheep
crushing birds or eggs, disturbance or mortality caused by herds or
working dogs, and the loss of habitat from overgrazing by sheep. The
petitioner also reports that the southern white-tailed ptarmigan also
may alter its movement behaviors in heavily grazed areas of the Rocky
Mountains (Hoffman 2006, p. 26).
Native ungulates also graze in alpine areas, and the petitioner
asserts that, like sheep, they too may impact the habitats of the
southern and Mt. Rainier white-tailed ptarmigans. The petitioner
indicates that populations of elk (Cervus elaphus) have grown
dramatically in the contiguous United States as natural predators
disappeared and States enforced game laws (Hoffman 2006, pp. 36, 42).
Consequently, the petitioner states that elk graze in alpine ranges
more frequently during all seasons of the year (Hoffman 2006, p. 42).
The petitioner cites one study that determined that willow habitats
found below treeline that are overgrazed by elk typically convert into
shrub-steppe habitats (Anderson 2007, pp. 401, 406). Although this
study focused on low-elevation, riparian habitats outside of the range
of either white-tailed ptarmigan subspecies, the petitioner predicts
that if alpine willow habitats above treeline are overgrazed by elk,
they too will turn into unfavorable shrub-steppe habitats.
The petitioner concludes that grazing by livestock and native
ungulates impacts white-tailed ptarmigan habitats, reduces the
availability of willows, and forces changes in migration patterns.
Evaluation of Information in the Petition and Available in Service
Files--Although the effects of livestock grazing on natural ecosystems
are well documented, the cited references and information in our files
do not address the impacts of cattle grazing on the southern and Mt.
Rainier white-tailed ptarmigans or their habitats. Cattle are not
generally a major influence in alpine environments, and while grazing
allotments for cattle may include alpine areas in the Rocky Mountains,
cattle are poorly adapted to high-elevation, alpine environments and,
therefore, are not likely to persist or overgraze in white-tailed
ptarmigan habitats. Where cattle grazing occurs in the alpine, the
references cited by the petitioner provide no evidence to conclude that
cattle have negatively impacted either subspecies of white-tailed
ptarmigan or their habitats. The petitioner provided no information and
we have no information in our files regarding cattle grazing in
Washington within the range of the Mt. Rainier white-tailed ptarmigan.
Sheep are more tolerant of alpine environments than cattle and can
graze in white-tailed ptarmigan habitats. Although the petitioner cites
USFS BEs identifying potential impacts to white-tailed ptarmigan and
their habitats in the Rocky Mountains from sheep grazing, these BEs
determined that grazing would not contribute to a loss of viability or
lead to a trend towards Federal listing. The petitioner provided no
evidence and we have no information to indicate that the impacts
evaluated by the BEs actually occurred or that they may threaten the
subspecies. The petitioner provided no information and we have no
information in our files regarding sheep grazing and the Mt. Rainier
white-tailed ptarmigan in Washington. While sheep may feed on the same
willows and other alpine plants as the white-tailed ptarmigan, we found
no information to support that competition for food between sheep and
ptarmigans negatively impacts either subspecies. Additionally, although
the petitioner cites anecdotal observations that ptarmigans may move
away from heavily grazed areas, the cited references and information in
our files do not provide evidence that this movement or disruption may
be a threat to either subspecies.
Finally, we found no evidence to conclude that elk overgraze on
alpine vegetation at any time of the year such that either subspecies
may show a negative response. The petitioner asserts that elk use of
the alpine has increased during all seasons of the year, but elk
generally move down to lower elevations during the winter (Fitzgerald
et al. 1994, p. 385). At these lower wintering elevations, elk are more
removed from ptarmigans and their alpine habitats when the birds are
congregating in their snow-covered wintering areas and feeding on
willow. Similarly, we have no information in our files nor does the
petitioner provide information to indicate that alpine willow habitats
that are overgrazed by elk change into shrub-steppe habitats that may
be unfavorable to the southern or Mt. Rainier white-tailed ptarmigan,
or grazed to the extent to which either population of the subspecies
may be negatively impacted. Finally, the petitioner provided no
information and
[[Page 33151]]
we have no information in our files regarding elk grazing in the alpine
habitats of the Mt. Rainier white-tailed ptarmigan or any potential
impacts to the subspecies. Therefore, we find that the petition and
information in our files do not present substantial scientific or
commercial information to indicate that habitat impacts attributed to
grazing may be a threat to the southern or Mt. Rainier white-tailed
ptarmigan.
Mining
Information Provided in the Petition--The petitioner asserts that
mining has destroyed alpine habitats and that pollutants from abandoned
mines threaten the southern and Mt. Rainier white-tailed ptarmigans.
Compared to recreation and grazing, the petitioner considers mining the
most destructive human activity in alpine habitats and provides
evidence where mining historically degraded alpine ecosystems, damaged
soils, destroyed vegetation, and polluted watersheds in the Rocky
Mountains (Brown et al. 1978, p. 23; Chambers 1997, p. 161; Macyk 2000,
p. 537; Clements et al. 2000, p. 626). The petitioner also presents
research showing that white-tailed ptarmigans are susceptible to toxic
pollutants leeching from abandoned mines that have not been properly
reclaimed (Larison et al. 2000, p. 181). In southwestern Colorado, the
southern white-tailed ptarmigan exhibited calcium deficiencies, skewed
sex ratios, and other physiological effects after eating willows
contaminated with cadmium, a toxic heavy metal found at abandoned mines
(Larison et al. 2000, p. 181). The petitioner also cites two BEs
prepared by the USFS in Colorado that determined that vehicles operated
at mines could drive over nests, crush eggs, and disturb the summer
foraging habitats of the white-tailed ptarmigan.
Evaluation of Information in the Petition and Available in Service
Files--In the Rocky Mountains, historic and current mining operations
occurred within the range of the southern white-tailed ptarmigan and
may have reduced available habitats. However, the available information
cited by the petitioner and available in our files does not indicate
that these mining operations significantly reduced or fragmented
habitats to an extent that the southern white-tailed ptarmigan has
shown a negative population response. Although the petitioner cites
USFS BEs that determined impacts to the white-tailed ptarmigan would
occur at mines in the Rocky Mountain Region, these evaluations also
determined that the mining operations would not contribute to a loss of
viability or lead to a trend towards Federal listing. We have no
information to indicate that these impacts actually occurred or that
the southern white-tailed ptarmigan exhibited a negative population
response as a result. Additionally, cadmium poisoning in white-tailed
ptarmigan has only been observed in improperly reclaimed mines within
the ore-belt of southwestern Colorado; there is no evidence of cadmium
poisoning elsewhere in the Rocky Mountains or Washington (Hoffman 2006,
p. 47). While ptarmigan in the ore-belt of southwestern Colorado may be
poisoned after eating contaminated willows, we found no information to
conclude that this occurs at a level that impacts the subspecies.
Finally, the petitioner provided no information and we have no
information regarding mining or potential effects within the range of
the Mt. Rainier white-tailed ptarmigan in Washington. Therefore, we
find that the petition and information in our files do not present
substantial scientific or commercial information to indicate that
habitat impacts due to mining activities may be a threat to the
southern or Mt. Rainier white-tailed ptarmigan.
Summary of Factor A
Based on the information provided in the petition, as well as other
information readily available in our files, we find that the petition
presents substantial scientific or commercial information indicating
that the southern white-tailed ptarmigan and Mt. Rainier white-tailed
ptarmigan may warrant listing due to the present or threatened
destruction, modification, or curtailment of the species' habitat or
range as a result of the habitat changes brought about by the effects
of global climate change. We find that the petition does not present
substantial scientific or commercial information indicating that the
southern or Mt. Rainier white-tailed ptarmigan may warrant listing due
to the present or threatened destruction, modification, or curtailment
of the species' habitat or range from recreation, livestock grazing, or
mining. However, we will more fully evaluate these activities in our
status review.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Information Provided in the Petition
The petitioner claims that hunting threatens the white-tailed
ptarmigan and provides general background information on ptarmigan
hunting regulations in the United States. Hunting of white-tailed
ptarmigan is legal in Alaska, Colorado, Utah, and California (Hoffman
2006, p. 47). The white-tailed ptarmigan is not hunted in New Mexico,
Montana, Wyoming, or Washington. The petitioner reports that the
current threat of hunting to white-tailed ptarmigan populations is
localized, and, therefore, populations may be susceptible to
overharvest based on a variety of factors. The petitioner indicates
that white-tailed ptarmigans are unwary, congregate in large flocks,
and return to habitats even after they are repeatedly disturbed. The
petitioner asserts that this behavior may make the birds easy to hunt.
The petitioner also explains that approximately 95 percent of the
occupied range of the southern white-tailed ptarmigan in Colorado is
publicly owned and open to hunting (Hoffman 2006, p. 9). Much of this
occupied range is close to metropolitan areas and accessible to
hunters. The petitioner also reports that declining populations of
other grouse species are causing a renewed interest in the white-tailed
ptarmigan among hunters. Additionally, where brood habitat is limited
and occurs along rocky areas, female white-tailed ptarmigans may be
easier to detect than males, easier to hunt, and more susceptible to
hunting mortality (Sandercock et al. 2005, p. 22; Hoffman 2006, p. 47).
The petitioner cites a dissertation that estimated a 15 to 27
percent higher mortality rate in hunted white-tailed ptarmigan
populations, which suggested that hunting results in additive mortality
(Hoffman 2006, p. 47). However, the petitioner argues that population
declines of white-tailed ptarmigan associated with hunting may not be
readily apparent. The petitioner cites a study on willow grouse
(Lagopus lagopus lagopus) in Sweden and a study on ruffed grouse
(Bonasa umbellus) in Wisconsin to explain that immigration from non-
hunted or lightly hunted populations may sustain breeding densities of
white-tailed ptarmigan in heavily hunted areas (Small et al. 1991, p.
512; Smith and Willebrand 1999, p. 722; Hoffman 2006, p. 47). The
petitioner reasons that because breeding densities for other species of
grouse remain stable with immigration, the effects of hunting on white-
tailed ptarmigan populations may be difficult to detect.
Evaluation of Information in the Petition and Available in Service
Files
Wyoming classifies the southern white-tailed ptarmigan as a game
bird, but does not permit hunting due to its restricted distribution
and small population size in the State (Braun et al. 1993, p. 1;
Hoffman 2006, p. 10). New
[[Page 33152]]
Mexico also does not permit hunting of the southern white-tailed
ptarmigan. Similarly, Washington does not permit hunting of the Mt.
Rainier white-tailed ptarmigan. In the States where hunting is not
permitted, the petitioner provided no information and we have no
information in our files to suggest that illegal hunting may be a
threat to either the southern or Mt. Rainier white-tailed ptarmigan.
Colorado permits the legal hunting of the southern white-tailed
ptarmigan. In Colorado, daily bag and possession limits are 3 and 6
birds, respectively, and the hunting season is 23 days long, commencing
in mid-September when young ptarmigans have reached adulthood and can
survive independently from the brood hen (Hoffman 2006, p. 10). The
hunting season in Colorado ends before ptarmigans start congregating on
wintering areas, when they are most susceptible to overharvest (Hoffman
2006, p. 10). The short season and small bag limits of the hunting
season in Colorado are designed to prevent overharvesting (Hoffman
2006, p. 10). While ptarmigans may be unwary of humans, relatively easy
to hunt, and found primarily on public lands, there is no information
to suggest that illegal harvest by hunters may be a threat to the
southern white-tailed ptarmigan in Colorado. Although immigration may
make it difficult to detect the effects of hunting on other species of
grouse, we have no information to suggest that hunting has resulted in
additive mortality to the southern or Mt. Rainier white-tailed
ptarmigan such that populations are unable to sustain viable breeding
densities. Similarly, we have no information to suggest that hunting
the species is currently more popular such that overharvesting may be a
threat to the southern white-tailed ptarmigan. Therefore, we find that
the petition and information in our files do not present substantial
scientific or commercial information to indicate that hunting may be a
threat to the southern or Mt. Rainier white-tailed ptarmigan. However,
we will more fully evaluate hunting in our status review.
C. Disease or Predation
Information Provided in the Petition
The petitioner asserts that the development of ski areas increases
the presence of generalist predators that threaten the white-tailed
ptarmigan in alpine habitats. As support, the petitioner cites a study
on rock ptarmigan in Scotland that reported an increase in generalist
predators, such as carrion crows (Corvus corone), feeding on birds and
eggs following the development of a ski area (Watson and Moss 2004, p.
267). In this study, the rock ptarmigans that nested closest to
developed areas lost more nests to predation by crows or gulls and
reared abnormally few broods compared to ptarmigans that nested farther
away from development (Watson and Moss 2004, p. 267; Hoffman 2006, p.
44). The petitioner argues that this study on the rock ptarmigan in
Scotland is applicable to white-tailed ptarmigan populations in the
United States. Although the petitioner states that specific studies
regarding post-development increases in generalist predators and the
potential effects on the white-tailed ptarmigan are lacking, the
petitioner stresses that any development that increases generalist
predators can impact the number of juvenile white-tailed ptarmigans in
the population (Storch 2007, pp. 12, 40).
Evaluation of Information in the Petition and Available in Service
Files
In the presence of suitable habitats, predation is generally not a
limiting factor for ptarmigans, as the birds have evolved closely with
their predators and developed strategies to compensate for high
predation rates (Hoffman 2006, p. 34). Although ski resorts or other
human developments may attract predators, there is no information from
the petition or our files to indicate that predation in any part of the
range has exceeded any population-level compensation strategies to
negatively impact southern and Mt. Rainier white-tailed ptarmigans.
Although the petitioner provides evidence of predation of rock
ptarmigan at ski resorts in Scotland, we have no information to
conclude that there are more predators at ski resorts in the United
States, that predation on white-tailed ptarmigan populations has
increased, or that predation may be a threat to either subspecies. The
petitioner provides no specific information regarding ski areas and the
Mt. Rainier white-tailed ptarmigan in Washington. Ski areas and other
forms of human development, such as roads, may enable predators to
access alpine habitats, but there is no information in the petition or
our files to indicate that predation within any part of the range of
the southern or Mt. Rainier white-tailed ptarmigan may be a threat,
regardless of the proximity of occupied habitats to development.
The petitioner provides no information regarding any disease or
pathogen that threatens the southern or Mt. Rainier white-tailed
ptarmigans, and we found no evidence in our files that the subspecies
may be at risk from any specific disease or pathogen. Therefore, we
find that the petition and information in our files do not present
substantial scientific or commercial information to indicate that
disease or predation may be threats to the southern or Mt. Rainier
white-tailed ptarmigans. However, we will more fully evaluate potential
threats associated with disease and predation in our status review.
D. The Inadequacy of Existing Regulatory Mechanisms
Information Provided in the Petition
The petitioner claims that existing regulatory mechanisms are
inadequate to prevent the decline of the white-tailed ptarmigan because
global and national regulations are failing to reduce carbon emissions
to levels that will slow global surface warming. They also assert that
no legal mechanisms currently exist to regulate greenhouse gases on a
national level in the United States. The petitioner argues that
stabilizing current climatic conditions through reductions in
greenhouse gas emissions is necessary to preserve the remaining alpine
habitats of the white-tailed ptarmigan, as discussed under Factor A,
above. The petitioner also argues that other regulatory mechanisms
inadequately protect the white-tailed ptarmigan from threats other than
climate change. The petitioner argues that changes in climate caused by
human activities must be mitigated through stronger regulatory
mechanisms because the existing mechanisms are inadequate.
The petitioner stresses that legislative action is necessary to
save the white-tailed ptarmigan because scientists warn that we are
approaching emissions levels that would cause dangerous climate change
(Hansen et al. 2008, pp. 217-218). The petitioner stresses that with
current atmospheric carbon dioxide levels at approximately 390 parts
per million (ppm), and worldwide emissions continuing to increase by
more than 2 ppm each year, immediate reductions in greenhouse gas
emissions are necessary to prevent the loss of species and ecosystems
to climate change.
The petitioner reports that the United States produces
approximately 20 percent of worldwide carbon dioxide emissions each
year (U.S. Energy Information Administration 2010), yet lacks adequate
regulations to reduce the greenhouse gas emissions. The petitioner
cites the Service's 2008 listing of the polar bear (Ursus maritimus),
which recognized that there are no regulatory mechanisms that address
the anthropogenic causes of climate change (e.g., greenhouse gas
emissions) and the
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impact of warming temperatures and altered precipitation patterns on
diminishing sea ice (73 FR 28288, May 15, 2008). The petition also
states that existing domestic laws which grant authority to require
greenhouse gas emissions reductions (e.g., Clean Air Act, Clean Water
Act, Endangered Species Act, Energy Policy and Conservation Act) are
not fully implemented. As an example, the petitioner references the
U.S. Environmental Protection Agency's (EPA's) implementation of the
Clean Air Act (42 U.S.C. 7401 et seq.) to lower emissions by requiring
improved fuel economy and higher emission standards for light-duty
vehicles (75 FR 25324, May 7, 2010), but states that the majority of
other Clean Air Act programs are not fully implemented to address
greenhouse gas emissions (75 FR 17004, April 2, 2010). The petitioner
argues that full implementation of these environmental laws would
provide an effective and comprehensive greenhouse gas reduction
strategy, but does not explain how the majority of these laws could be
applied to control emissions.
The petitioner also indicates that the international agreements
that address greenhouse gas emissions (e.g., United Nations Framework
Convention on Climate Change, Kyoto Protocol) rely on non-binding and
ineffective controls (Pew 2010, p. 1; Rogelj et al. 2010, p. 464).
Therefore, the petitioner considers international regulatory mechanisms
inadequate to protect the white-tailed ptarmigan from climate change.
Furthermore, the petitioner contends that other State and Federal
regulatory mechanisms in the United States do not adequately protect
the white-tailed ptarmigan from threats other than climate change. The
petitioner asserts that the National Environmental Policy Act (NEPA; 42
U.S.C. 4321 et seq.) does not prohibit Federal agencies from choosing
project alternatives that may negatively affect individuals or
populations of white-tailed ptarmigans. The USFS recognizes the white-
tailed ptarmigan as a sensitive species in its Rocky Mountain (Region
2) and Southwest Region (Region 3), but the petitioner contends that
because the NEPA does not require avoidance of harm, the sensitive
species designation provides little regulatory protection. The
petitioner cites 41 BEs prepared by the USFS in the Rocky Mountain
Region within the last 10 years that evaluated activities that could
harm ptarmigan. The petitioner also explains that the National Forest
Management Act (16 U.S.C. 1600 et seq.) does not prohibit the USFS from
carrying out actions that harm the white-tailed ptarmigan or its
habitats.
Finally, the petitioner explains that the State of New Mexico added
the white-tailed ptarmigan to its list of endangered species in 1975,
and as a species of greatest conservation need in 2006. The petitioner
argues that these designations in New Mexico confer no regulatory
authority to protect white-tailed ptarmigan habitats. The petitioner
provides no information or analysis regarding State regulations in
either Colorado or Washington.
The petitioner concludes that, given the threat of climate change
as discussed under Factor A, it is important to protect all existing
alpine habitats in order to provide the species with the best possible
chance to find suitable habitats in a warmer world. The petitioner
argues that none of the existing regulatory mechanisms provide
substantial protection for the white-tailed ptarmigan from other
threats discussed under Factor A, such as livestock grazing,
recreation, or mining.
Evaluation of Information in the Petition and Available in Service
Files
According to the IPCC, anthropogenic emissions of long-lived
greenhouse gases, especially carbon dioxide, are currently contributing
the largest positive radiative forcings (leading to warming of climate)
of any climate factor (Forster et al. 2007, pp. 136-137). After
providing scientific references in support of global climatic warming
as discussed under Factor A, the petitioner refers to the limited
application of the Clean Air Act by the EPA to effectively regulate
greenhouse gas emissions. Information in our files indicates that on
December 15, 2009, the EPA announced that current and projected
concentration of six greenhouse gases in the atmosphere threaten the
public health and welfare of current and future generations (74 FR
66496). In effect, the EPA concluded that the greenhouse gases linked
to climate change are pollutants whose emissions can be subject to the
Clean Air Act (42 U.S.C. 7401 et seq.).
The EPA proposed specific regulations to limit greenhouse gas
emissions under the Clean Air Act in 2010. However, specific
regulations to limit greenhouse gas emissions were only proposed in
2010, and have not yet been finalized. Therefore, the Clean Air Act
cannot, at present, be considered an existing regulatory mechanism that
addresses greenhouse gas emissions. Nor do we have any basis to
conclude that implementation of the Clean Air Act in the foreseeable
future (40 years, based on global climate projections) may
substantially reduce the current rate of global climate change through
regulation of greenhouse gas emissions. Thus, we conclude that the
Clean Air Act is not designed to specifically address the primary
threats to the southern and Mt. Rainier white-tailed ptarmigans,
including the loss of alpine habitats and other environmental changes
associated with climate change, as discussed under Factor A.
Given that the petition, as revised, is specifically for the
southern and Mt. Rainier white-tailed ptarmigan, we do not consider the
adequacy of existing international regulations, treaties, or agreements
that do not directly apply to the United States, and to the subspecies,
when evaluating possible threats under Factor D. There is no
information in the petition or in our files regarding applicable
international regulations or treaties that might alleviate threats to
the southern and Mt. Rainier white-tailed ptarmigans in the United
States. Also, concerning the petitioner's assertion that NEPA does not
provide adequate regulatory protection, NEPA is a disclosure law which
does not require subsequent minimization or mitigation measures by the
Federal agency involved. Although Federal agencies may include
conservation measures for sensitive species as a result of the NEPA
process, any such measures are voluntary in nature and not required by
the statute. Thus it is outside the scope of NEPA to provide regulatory
protections to species. As with the Clean Air Act, NEPA is not designed
to specifically address the specific threats to the southern and Mt.
Rainier white-tailed ptarmigans.
In the Rocky Mountains, approximately 95 percent of occupied
ptarmigan habitats are on public lands, 85 percent of which are
administered by the USFS (Hoffman 2006, p. 9). The petitioner did not
provide information, and we found no information in our files,
regarding the land ownership and corresponding management regulations
for alpine habitats in Washington. Because the ptarmigan is a USFS
sensitive species in the Rocky Mountains, the USFS actively manages it
to avoid trends toward Federal listing and to maintain population
viability across its range in Regions 2 and 3. The petitioner argues
that according to BEs, 41 projects administered by the USFS within the
last 10 years in the Rocky Mountain Region harmed the white-tailed
ptarmigan. The petitioner previously indicated that 8 of these projects
were associated with sheep grazing, 2 were associated with mining, and
27 were associated with recreation. However, the USFS determined that
[[Page 33154]]
these activities would not contribute to a loss of viability or lead to
a trend towards Federal listing, and the petitioner does not provide
evidence these projects actually occurred or contributed to a trend
towards listing contrary to the USFS' determination. The petitioner
also does not provide evidence that State regulations in New Mexico are
ineffective and may threaten the southern white-tailed ptarmigan. The
petitioner provides no information, and we have no information in our
files, regarding regulations or laws specific to the Mt. Rainier white-
tailed ptarmigan in Washington.
Summary of Factor D
We are not aware of any existing regulatory mechanisms that are
designed to address the changes described in Factor A in the southern
and Mt. Rainier white-tailed ptarmigan habitats that are occurring or
likely to occur in the future.
As discussed above, there are no applicable international
regulations or treaties that might alleviate threats to the southern
and Mt. Rainier white-tailed ptarmigans in the United States.
Similarly, it is beyond the scope of NEPA to provide specific
protections to the subspecies.
Approximately 95 percent of the occupied range of the southern
white-tailed ptarmigan in the Rocky Mountains occurs on public lands,
at least 85 percent of which is federally managed (Hoffman 2006, p. 9).
Public lands are subject to several Federal laws and regulations that
protect habitats from direct destruction or modification. There is no
information in the petition nor readily available in our files
regarding laws or regulations in the State of Washington and the
effectiveness of regulations in other States, and it is uncertain
whether Federal or State laws and regulations adequately address the
potential threats to habitats of the white-tailed ptarmigan associated
with climate change as discussed under Factor A. Existing regulatory
mechanisms are not designed to, nor do they, ameliorate the threats to
the southern or Mt. Rainier white-tailed ptarmigan. Therefore, we find
that the petition and information in our files do not present
substantial scientific or commercial information to indicate that the
inadequacy of existing regulatory mechanisms may be a threat to the
southern or Mt. Rainier white-tailed ptarmigans. We will more fully
evaluate existing regulatory mechanisms in our status review.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
In their petition, the petitioner presented information regarding
potential physiological effects of a warming climate on the southern
and Mt. Rainier white-tailed ptarmigans under Factor A. Because these
are physiological effects, we discuss these assertions below. The
petitioner also claims that population isolation and limited dispersal
distances threaten the white-tailed ptarmigan.
Physiological Response to Climate Warming
Information Provided in the Petition--The petitioner cites a study
conducted in the RMNP, Colorado, as evidence that warming temperatures
have had a negative effect on the population dynamics of white-tailed
ptarmigan (Wang et al. 2002, pp. 81-86). The petitioner also explains
that increased temperatures may not only decrease population growth
rates of the white-tailed ptarmigan, but also may directly impact
individual ptarmigans because of their inability to cope with the
stress caused by warming temperatures. The petitioner explains that the
southern and Mt. Rainier white-tailed ptarmigans are well adapted to
their seasonally cold alpine habitats, but are not physiologically
adapted to high ambient air temperatures (Hoffman 2006, p. 24). To
support this claim, the petitioner cites several studies that
determined that the white-tailed ptarmigan has low mean body
temperatures, a wide temperature-tolerance zone, excellent insulation
to trap body heat, and low evaporative efficiencies (Veghte and Herreid
1965, p. 267; Lasiewski et al. 1966, p. 445; Johnson 1968, p. 1003;
Hoffman 2006, pp. 24, 45). The petitioner argues that southern and Mt.
Rainier white-tailed ptarmigans are susceptible to heat stress and
underequipped to adapt to the warming temperatures associated with
climate change.
The petitioner explains that white-tailed ptarmigans modify their
behaviors to avoid overheating, but this may not be sufficient to
compensate for a warming climate. While nesting, female white-tailed
ptarmigans take incubation breaks to forage, but they may take fewer
breaks if temperatures are high. With less food, as a result of fewer
foraging breaks, the health of nesting females may deteriorate, and
they may abandon the nest (Hoffman 2006, p. 46). Additionally, the
petitioner suggests that warming temperatures may force females to nest
in shaded, denser vegetation, where they may be more susceptible to
predation (Hoffman 2006, p. 46). Therefore, the petitioner concludes
that behavioral adaptations that ptarmigans employ to avoid overheating
may be ineffective with a warming climate.
Evaluation of Information in the Petition and Available in Service
Files--Empirical studies show that warm ambient temperatures negatively
affected the population dynamics of the southern white-tailed ptarmigan
in Colorado by depressing population growth rates and skewing hatch
dates (Wang et al. 2002, p. 81). This study reported that increases in
April and May temperatures between years 1975 through 1999 at RMNP
significantly advanced the median hatch dates of ptarmigan eggs and
depressed the population growth rate of ptarmigans in RMNP (Wang et al.
2002, p. 85). Additionally, a population model anticipated that warming
resulted in population decreases from 30 to 40 birds to 2 to 3 birds in
RMNP (Wang et al. 2002, p. 84-85). This study concluded that there is a
clear population-level response in white-tailed ptarmigans to climate
change, and that predicted temperature increases in RMNP may accelerate
population declines and increase the probability of local extinction
(Wang et al. 2002, p. 86).
As discussed under Factor A, global climate change may result in an
increase in temperatures within the habitats of the southern and Mt.
Rainier white-tailed ptarmigans; and the effect of increasing
temperatures may decrease population growth rates. Additionally, the
southern and Mt. Rainier white-tailed ptarmigans are physiologically
well adapted to conserve heat and tolerate the cold temperatures of
their alpine environments. However, available information suggests that
these adaptations are detrimental to the white-tailed ptarmigan in warm
temperatures, with heat stress developing quickly when the birds are
unable to cool off (Johnson 1968, p. 1012; Hoffman 2006, pp. 24, 31).
Although the birds seek cooler microclimates with shade and cover to
escape warm temperatures, climatic warming may reduce the number of
these cooler microclimates available, and the southern and Mt. Rainier
white-tailed ptarmigans may be incapable of avoiding heat stress. If
physiologically unable to cool body temperatures through evaporation,
guttural fluttering, bathing in snow, or relocating to cooler
microclimates, heat stress aggravated by climate change may be a threat
to the southern or Mt. Rainier white-tailed ptarmigan. However, the
petitioner did
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not provide information, and we found no evidence in our files to
indicate, that the birds are more susceptible to predation in cooler
microclimate areas or that females will take fewer foraging breaks so
that malnutrition eventually reduces breeding success eventually
resulting in a negative population response. But, as discussed above,
we still find that warming temperatures associated with climate change
may be a threat by depressing population growth rates and aggravating
heat stress. Therefore, we find that the information presented in the
petition and information in our files presents substantial scientific
or commercial evidence to indicate the physiological response of the
southern or Mt. Rainier white-tailed ptarmigan to climate warming may
be a threat.
Population Isolation and Limited Dispersal Distances
Information Presented in the Petition--The petitioner claims that
isolation, small populations, low densities, and limited dispersal
distances render the southern and Mt. Rainier white-tailed ptarmigans
particularly vulnerable to extinction. To support this claim, the
petitioner cites a species account for the Vancouver Island white-
tailed ptarmigan, the subspecies endemic to Vancouver Island, which
indicates that this subspecies exists in low densities with stochastic
population dynamics and environmental conditions (Martin and Forbes
2004, pp. 4-5). The petitioner also provides the USFS sensitive species
designation for the white-tailed ptarmigan in the Rocky Mountain Region
as evidence that population isolation and limited dispersal distances
are a threat (USFS 2005, p. 1). The petitioner also explains that
alpine habitats are isolated and geographically separated by expanses
of unsuitable habitats, and that distances between habitats exceed the
maximum recorded travel distances for the white-tailed ptarmigan
(Martin et al. 2000, p. 514). Therefore, the petitioner concludes that
as climate change modifies and reduces available habitats, distances
between suitable habitats will increase, further isolating populations
and threatening the subspecies.
Evaluation of Information in the Petition and Available in Service
Files--While the Vancouver Island white-tailed ptarmigan may be
susceptible to population extirpations because of their low densities,
patchy habitats, and stochastic environment, we found no information in
the petition nor available in our files that these variables may be
threats to either the southern or the Mt. Rainier white-tailed
ptarmigan. Contrary to the Vancouver Island white-tailed ptarmigan
study, a study in the Rocky Mountains suggested that small population
sizes, low densities, relatively low fecundity, and high annual
variation in most population parameters did not appear to threaten the
white-tailed ptarmigan population (Martin et al. 2000, p. 512).
Additional information suggests that a well-developed system of
population exchange and recruitment allows ptarmigans to persist in
isolated, small populations, even during regional stochastic events in
Colorado (Martin et al. 2000, pp. 512, 514). The petitioner provided no
information regarding maximum distances between alpine habitats that
may hinder population exchange or recruitment, and we have no
information indicating that the current distances between alpine
habitats may impede interchange for the southern or Mt. Rainier white-
tailed ptarmigans. While climate change may increase the distance
between alpine habitats, the petitioner did not provide information,
and we have no information in our files, that distances between alpine
habitats may threaten either subspecies. Additionally, the USFS
sensitive species recommendation and evaluation for white-tailed
ptarmigan summarizes potential threats, but provides no supporting
information regarding population isolation or dispersal distances.
Therefore, we find that the petition and information in our files do
not present substantial scientific or commercial information to
indicate that isolated populations or limited dispersal distances may
be threats to the southern and Mt. Rainier white-tailed ptarmigans.
Summary of Factor E
We find that the information presented in the petition regarding
population growth rates and physiological response to a warming climate
presents substantial scientific or commercial evidence to indicate that
the petitioned action may be warranted. We find that the petition does
not present substantial scientific or commercial information to
indicate that population isolation or limited dispersal distances may
be threats to the southern and Mt. Rainier white-tailed ptarmigans. We
will evaluate population isolation and limited dispersal distances more
fully during our status reviews.
Finding
On the basis of our determination under section 4(b)(3)(A) of the
Act, we have determined that the petition presents substantial
scientific or commercial information indicating that listing the
southern and Mt. Rainier white-tailed ptarmigans throughout the entire
ranges of both subspecies may be warranted. This finding is based on
information provided under factors A and E. The information provided in
the petition and available in our files under factors B, C, and D is
not substantial. During the status review, we will fully address the
cumulative effects of threats discussed under each factor.
Because we have found that the petition presents substantial
information indicating that listing the southern and Mt. Rainier white-
tailed ptarmigans may be warranted, we are initiating a status review
to determine whether listing these subspecies under the Act is
warranted.
The ``substantial information'' standard for a 90-day finding
differs from the Act's ``best scientific and commercial data'' standard
that applies to a status review to determine whether a petitioned
action is warranted. A 90-day finding does not constitute a status
review under the Act. In a 12-month finding, we will determine whether
a petitioned action is warranted after we have completed a thorough
status review of the subspecies, which is conducted following a
substantial 90-day finding. Because the Act's standards for 90-day and
12-month findings are different, as described above, a substantial 90-
day finding does not necessarily mean that the 12-month finding will
result in a warranted finding.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Colorado
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Authors
The primary authors of this notice are staff members of the
Colorado Ecological Services Field Office (see FOR FURTHER INFORMATION
CONTACT).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: May 21, 2012.
Gregory E. Siekaniec,
Deputy Director, U.S. Fish and Wildlife Service.
[FR Doc. 2012-13320 Filed 6-4-12; 8:45 am]
BILLING CODE 4310-55-P