[Federal Register: December 14, 2010 (Volume 75, Number 239)]
[Proposed Rules]
[Page 78029-78061]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14de10-19]
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Part III
Department of the Interior
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Fish and Wildlife Service
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50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 12-Month Finding on a
Petition To List the North American Wolverine as Endangered or
Threatened; Proposed Rule
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R6-ES-2008-0029; MO 92210-0-0008-B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List the North American Wolverine as Endangered or
Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list the North American wolverine
(Gulo gulo luscus) as an endangered or threatened species under the
Endangered Species Act of 1973, as amended (Act). After review of all
available scientific and commercial information, we find that the North
American wolverine occurring in the contiguous United States is a
distinct population segment (DPS) and that addition of this DPS to the
Lists of Endangered and Threatened Wildlife and Plants is warranted.
Currently, however, listing the contiguous U.S. DPS of the North
American wolverine is precluded by higher priority actions to amend the
Lists of Endangered and Threatened Wildlife and Plants. Upon
publication of this 12-month petition finding, we will add the
contiguous U.S. DPS of the wolverine to our candidate species list. We
consider the current range of the species to include portions of the
States of Washington, Idaho, Montana, Wyoming, Colorado, Utah, Oregon,
and California. However, due to the dispersal abilities of individual
wolverines, we expect that wolverines are likely to travel outside the
currently occupied area. We will develop a proposed rule to list this
DPS as our priorities allow (see section on Preclusion and Expeditious
Progress). We will make any determination on critical habitat during
development of the proposed listing rule. In the interim, we will
address the status of this DPS through our annual Candidate Notice of
Review.
DATES: This finding was made on December 14, 2010.
ADDRESSES: This finding is available on the Internet at http://
www.regulations.gov at Docket Number FWS-R6-ES-2008-0029. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Montana Field Office, U.S. Fish and Wildlife
Service, 585 Shepard Way, Helena, MT 59601; telephone (406) 449-5225.
Please submit any new information, materials, comments, or questions
concerning this finding to the above address.
FOR FURTHER INFORMATION CONTACT: Mark Wilson, Field Supervisor, U.S.
Fish and Wildlife Service, Montana Field Office (see ADDRESSES); by
telephone at 406-449-5225; or by facsimile at 406-449-5339. If you use
a telecommunications device for the deaf (TDD), call the Federal
Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires
that, for any petition to revise the Federal Lists of Endangered and
Threatened Wildlife and Plants that contains substantial scientific and
commercial information that listing a species may be warranted, we make
a finding within 12 months of the date of receipt of the petition. In
this finding, we determine whether the petitioned action is: (a) Not
warranted, (b) warranted, or (c) warranted, but the immediate proposal
of a regulation implementing the petitioned action is precluded by
other pending proposals to determine whether species are threatened or
endangered, and whether expeditious progress is being made to add or
remove qualified species from the Federal Lists of Endangered and
Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires
that we treat a petition for which the requested action is found to be
warranted but precluded as though resubmitted on the date of such
finding, that is, requiring a subsequent finding to be made within 12
months. We must publish these 12-month findings in the Federal
Register.
Previous Federal Actions
On April 19, 1995, we published a finding (60 FR 19567) that a
previous petition, submitted by the Predator Project (now named the
Predator Conservation Alliance) and Biodiversity Legal Foundation to
list the wolverine in the contiguous United States, did not provide
substantial information indicating that listing the wolverine in the
contiguous United States may be warranted.
On July 14, 2000, we received a petition dated July 11, 2000,
submitted by the Biodiversity Legal Foundation, Predator Conservation
Alliance, Defenders of Wildlife, Northwest Ecosystem Alliance, Friends
of the Clearwater, and Superior Wilderness Action Network, to list the
wolverine within the contiguous United States as a threatened or
endangered species and designate critical habitat for the species.
On October 21, 2003, we published a 90-day finding that a petition
to list the wolverine in the contiguous United States failed to present
substantial scientific and commercial information indicating that
listing may be warranted (68 FR 60112).
On September 29, 2006, as a result of a complaint filed by
Defenders of Wildlife and others alleging we used the wrong standards
to assess the wolverine petition, the U.S. District Court, Montana
District, ruled that our 90-day petition finding was in error and
ordered us to make a 12-month finding for the wolverine. On April 6,
2007, a deadline for this 12-month finding was extended to February 28,
2008.
On March 11, 2008, we published a 12-month finding of ``not
warranted'' for the wolverine in the contiguous United States (73 FR
12929). In that finding we determined that the wolverine in the
contiguous United States did not constitute a distinct population
segment or a significant portion of the range of wolverines in North
America and so was not eligible for listing under the Act.
On July 8, 2008 we received a Notice of Intent to Sue from
Earthjustice alleging violations of the Act in our March 11, 2008, 12-
month finding. On September 30, 2008, Earthjustice filed a complaint in
the U.S. District Court, District of Montana, seeking to set aside and
remand the 12-month finding back to the Service for reconsideration.
On March 6, 2009, the Service agreed to settle the case with
Earthjustice by voluntarily remanding the 12-month finding and issuing
a new 12-month finding by December 1, 2010. Following the settlement
agreement, the court dismissed the case on June 15, 2009, and ordered
the Service to comply with the settlement agreement.
On April 15, 2010, the Service published a Notice of Initiation of
a 12-month finding for wolverines in the contiguous United States (75
FR 19591).
Species Information
Taxonomy and Life History
The wolverine has a holarctic distribution including northern
portions of Europe, Asia, and North America. The currently accepted
taxonomy classifies wolverines worldwide as a single species, Gulo
gulo. Old and New World wolverines are divided into separate
subspecies. Wolverines in the
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contiguous United States are a part of the New World subspecies, G. g.
luscus: the North American wolverine (Kurten and Rausch 1959 p. 19;
Pasitschniak-Arts and Lariviere 1995, p. 1). The species is known by
several common names including mountain devil, glutton, caracajou,
quickhatch, gulon, skunk bear, as well as wolverine.
The wolverine is the largest terrestrial member of the family
Mustelidae. Adult males weigh 12 to 18 kilograms (kg) (26 to 40 pounds
(lb), and adult females weigh 8 to 12 kg (17 to 26 lb) (Banci 1994, p.
99). The wolverine resembles a small bear with a bushy tail. It has a
broad, rounded head; short, rounded ears, and small eyes. Each foot has
five toes with curved, semi-retractile claws used for digging and
climbing (Banci 1994, p. 99).
A large number of female wolverines (40 percent) are capable of
giving birth at 2 years old, become pregnant most years, and produce
litter sizes of approximately 3.4 kits on average. Pregnant females
commonly resorb or spontaneously abort litters prior to giving birth
(Magoun 1985, pp. 30-31; Copeland 1996, p. 43; Persson et al. 2006, p.
77; Inman et al. 2007c, p. 70). It is likely that, despite the high
rate of initiation of pregnancy, due to the spontaneous abortion of
litters resulting from resource limitation, actual rates of successful
reproduction in wolverines are among the lowest known for mammals
(Persson 2005, p. 1456). In one study of known-aged females, none
reproduced at age 2, 3 of 10 first reproduced at age 3, and 2 did not
reproduce until age 4; the average age at first reproduction was 3.4
years (Persson et al. 2006, pp. 76-77). The average age at first
reproduction is likely more than 3 years (Inman et al. 2007c, p. 70).
It is common for females to forgo reproducing every year, possibly
saving resources to increase reproductive success in subsequent years
(Persson 2005, p. 1456). Supplemental feeding of females increases
reproductive potential (Persson 2005, p. 1456). Food-supplemented
females were also more successful at raising kits to the time of
weaning, suggesting that wolverine reproduction and ultimately
population growth rates and viability are food-limited. By age 3,
nearly all female wolverines become pregnant every year, but energetic
constraints due to low food availability result in loss of pregnancy in
about half of them each year. It is likely that, in many places in the
range of wolverines, it takes 2 years of foraging for a female to store
enough energy to successfully reproduce (Persson 2005, p. 1456).
Breeding generally occurs from late spring to early fall (Magoun
and Valkenburg 1983, p. 175; Mead et al. 1991, pp. 808-811). Females
undergo delayed implantation until the following winter to spring, when
active gestation lasts from 30 to 40 days (Rausch and Pearson 1972, pp.
254-257). Litters are born from mid-February through March, containing
one to five kits, with an average in North America of between 1 and 2
kits (Magoun 1985, pp. 28-31; Copeland 1996, p. 36; Krebs and Lewis
1999, p. 698; Copeland and Yates 2006, pp. 32-36; Inman et al. 2007c,
p. 68).
Female wolverines use natal (birthing) dens that are excavated in
snow. Persistent, stable snow greater than 1.5 meters (m) (5 feet (ft))
deep appears to be a requirement for natal denning, because it provides
security for offspring and buffers cold winter temperatures (Pulliainen
1968, p. 342; Copeland 1996, pp. 92-97; Magoun and Copeland 1998, pp.
1317-1318; Banci 1994, pp. 109-110; Inman et al. 2007c, pp. 71-72;
Copeland et al. 2010, pp. 240-242). Female wolverines go to great
lengths to find secure den sites, suggesting that predation is a
concern (Banci 1994, p. 107). Natal dens consist of tunnels that
contain well-used runways and bed sites and may naturally incorporate
shrubs, rocks, and downed logs as part of their structure (Magoun and
Copeland 1998, pp. 1315-1316; Inman et al. 2007c, pp. 71-72). In Idaho,
natal den sites occur above 2,500 m (8,200 ft) on rocky sites, such as
north-facing boulder talus or subalpine cirques in forest openings
(Magoun and Copeland 1994, pp. 1315-1316). In Montana, natal dens occur
above 2,400 m (7,874 ft) and are located on north aspects in avalanche
debris, typically in alpine habitats near timberline (Inman et al.
2007c, pp. 71-72). Offspring are born from mid-February through March,
and the dens are typically used through late April or early May
(Myrberget 1968, p. 115; Magoun and Copeland 1998, pp. 1314-1317; Inman
et al. 2007b, pp. 55-59). Occupation of natal dens is variable, ranging
from approximately 9 to 65 days (Magoun and Copeland 1998, pp. 1316-
1317).
Females may move kits to multiple secondary (maternal) dens as they
grow during the month of May (Pulliainen 1968, p. 343; Myrberget 1968,
p. 115), although use of maternal dens may be minimal (Inman et al.
2007c, p. 69). Timing of den abandonment is related to accumulation of
water in dens (due to snow melt), the maturation of offspring,
disturbance, and geographic location (Myrberget 1968, p. 115; Magoun
1985, p. 73). After using natal and maternal dens, wolverines may also
use rendezvous sites through early July. These sites are characterized
by natural (unexcavated) cavities formed by large boulders, downed logs
(avalanche debris), and snow (Inman et al. 2007c, p. 55-56).
Habitat, Space, and Food
In North America, wolverines occur within a wide variety of alpine,
boreal, and arctic habitats, including boreal forests, tundra, and
western mountains throughout Alaska and Canada. The southern portion of
the species' range extends into the contiguous United States, including
high-elevation alpine portions of Washington, Idaho, Montana, Wyoming,
California, and Colorado (Wilson 1982, p. 644; Hash 1987, p. 576; Banci
1994, p. 102, Pasitschniak-Arts and Lariviere 1995, p. 499; Aubry et
al. 2007, p. 2152; Moriarty et al. 2009, entire; Inman et al. 2009, pp.
22-25). Wolverines do not appear to specialize on specific vegetation
or geological habitat aspects, but instead select areas that are cold
and receive enough winter precipitation to reliably maintain deep
persistent snow late into the warm season (Copeland et al. 2010,
entire). The requirement of cold, snowy conditions means that, in the
southern portion of the species' range where ambient temperatures are
warmest, wolverine distribution is restricted to high elevations, while
at more northerly latitudes, wolverines are present at lower elevations
and even at sea level in the far north (Copeland et al. 2010, Figure
1).
In the contiguous United States, wolverines likely exist as a
metapopulation (Aubry et al. 2007, p. 2147, Figures 1, 3). A
metapopulation is a network of semi-isolated populations, each
occupying a suitable patch of habitat in a landscape of otherwise
unsuitable habitat (Pulliam and Dunning 1997, pp. 212-214).
Metapopulations require some level of regular or intermittent migration
and gene flow among subpopulations, in which individual populations
support one-another by providing genetic and demographic enrichment
through mutual exchange of individuals (Meffe and Carroll 1997, p.
678). Individual subpopulations may go extinct or lose genetic
viability, but are then ``rescued'' by immigration from other
subpopulations, thus ensuring the persistence of the metapopulation as
a whole. Metapopulation dynamics (the process of extinction and
recolonization by subpopulations) rely on the ability of subpopulations
to support one another through exchange of individuals for genetic and
demographic enrichment. If
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metapopulation dynamics break down, either due to changes within
subpopulations or loss of connectivity, then the entire metapopulation
may be jeopardized due to subpopulations becoming unable to persist in
the face of inbreeding or demographic and environmental stochasticity
(Pulliam and Dunning 1997b, pp. 221-222). We believe this outcome is
likely for wolverine, due to their naturally low reproductive rates and
low densities.
Wolverines are opportunistic feeders and consume a variety of foods
depending on availability. They primarily scavenge carrion, but also
prey on small animals and birds, and eat fruits, berries, and insects
(Hornocker and Hash 1981, p. 1290; Hash 1987, p. 579; Banci 1994, pp.
111-113). Wolverines have an excellent sense of smell that enables them
to find food beneath deep snow (Hornocker and Hash 1981, p. 1297).
Wolverines require a lot of space; the availability and
distribution of food is likely the primary factor in determining
wolverine movements and home range size (Hornocker and Hash 1981, p.
1298; Banci 1994, pp. 117-118). Female wolverines forage close to den
sites in early summer, progressively ranging further from dens as kits
become more independent (May et al. 2010, p. 941). Wolverines travel
long distances over rough terrain and deep snow, and adult males
generally cover greater distances than females (Hornocker and Hash
1981, p. 1298; Banci 1994, pp. 117-118; Moriarty et al. 2009, entire;
Inman et al. 2009, pp. 22-28; Brian 2010, p. 3; Copeland and Yates
2006, Figure 9). Home ranges of wolverines are large, and vary greatly
in size depending on availability of food, gender and age of the
animal, and differences in habitat quality. Home ranges of adult
wolverines also vary in size depending on geographic location. Home
ranges in Alaska were approximately 100 square kilometers (km\2\) to
over 900 km\2\ (38.5 square miles (mi\2\) to 348 mi\2\) (Banci 1994, p.
117). Average home ranges of resident adult females in central Idaho
were 384 km\2\ (148 mi\2\), and average home ranges of resident adult
males were 1,522 km\2\ (588 mi\2\) (Copeland 1996, p. 50). Wolverines
in Glacier National Park had average adult male home ranges of 496
km\2\ (193 mi\2\) and adult female home ranges of 141 km\2\ (55 mi\2\)
(Copeland and Yates 2006, p. 25). Wolverines in the Greater Yellowstone
Ecosystem had average adult male home ranges of 797 km\2\ (311 mi\2\),
and average adult female home ranges of 329 km\2\ (128 mi\2\) (Inman et
al. 2007a, p. 4). These home range sizes are large relative to the body
size of wolverines, and may indicate that wolverines occupy a
relatively unproductive niche in which they must forage over large
areas to consume the amount of calories needed to meet their life-
history requirements (Inman et al. 2007a, p. 11).
Wolverine Densities
Wolverines naturally occur in low densities of about 1 wolverine
per 150 km\2\ (58 mi\2\) with a reported range from 1 per 65 to 337
km\2\ (25 to 130 mi\2\) (Hornocker and Hash 1981, pp. 1292-1295; Hash
1987, p. 578; Copeland 1996, pp. 31-32; Copeland and Yates 2006, p. 27;
Inman et al. 2007a, p. 10; Squires et al. 2007, p. 2218). No systematic
population census exists over the entire current range of wolverines in
the contiguous United States, so the current population level and
trends remain unknown. However, based on our current knowledge of
occupied wolverine habitat and wolverine densities in this habitat, it
is reasonable to estimate that the wolverine population in the
contiguous United States numbers approximately 250 to 300 individuals
(Inman 2010b, pers. comm.). The bulk of the current population occurs
in the northern Rocky Mountains with a few individuals in the North
Cascades and one known individual each in the Sierra Nevada and
southern Rocky Mountains. Within the area known to currently have
wolverine populations relatively few wolverines can coexist due to
their naturally low population densities, even if all areas were
occupied at or near carrying capacity. Given the natural limitations on
wolverine population density, it is likely that historic wolverine
population numbers were also low (Inman et al. 2007a, Table 6). Because
of these natural limitations, we believe that densities and population
levels in the northern Rocky Mountains and North Cascades where
populations currently exist are likely not substantially lower than
population densities were in these areas prior to European settlement.
However, historically, the contiguous U.S. population would have been
larger than it is today due to the larger area occupied by populations
when the southern Rocky Mountains and Sierra Nevada were occupied at
full capacity.
Wolverine Status in Canada and Alaska
The bulk of the range of North American wolverines is found in
Canada and Alaska. Wolverines inhabit alpine tundra, boreal forest, and
arctic habitats in Canada and Alaska (Slough 2007, p. 78). Wolverines
in Canada have been divided into two populations for management by the
Canadian Government: An eastern population in Labrador and Quebec, and
a western population that extends from Ontario to the Pacific coast,
and north to the Arctic Ocean. The eastern population is currently
listed as endangered under the Species At Risk Act in Canada, and the
western population is designated as a species of special concern
(COSEWIC 2003, p. 8).
The current status of wolverines in eastern Canada is uncertain.
Wolverines have not been confirmed to occur in Quebec since 1978
(Fortin et al. 2005, p. 4). Historical evidence of wolverine presence
in eastern Canada is also suspect because no proof exists to show that
wolverine pelts attributed to Quebec or Labrador actually came from
that region; animals were possibly trapped elsewhere and the pelts
shipped through the eastern provinces (COSEWIC 2003, p. 20). Wolverines
in eastern Canada may currently exist in an extremely low-density
population, or may be extirpated. Wolverines in eastern Canada, both
historically and currently, could represent migrants from western
populations that never became resident animals (COSEWIC 2003, pp. 20-
21). The Federal Government of Canada has completed a recovery plan for
the eastern population with the goal of establishing a self-sustaining
population through reintroduction and protection (Fortin et al. 2005,
p. 16).
Wolverines in western Canada and Alaska inhabit a variety of
habitats from sea level to high in mountains (Slough 2007, pp. 77-78).
They occur in Ontario, Manitoba, Saskatchewan, Alberta, British
Columbia, Yukon, Northwest Territories, and Nunavut (Slough 2007, pp.
77-78). Since European colonization, a generally recognized range
contraction has taken place in boreal Ontario and the aspen parklands
of Manitoba, Saskatchewan, and Alberta (COSEWIC 2003, pp. 20-21; Slough
2007, p. 77). This range contraction occurred concurrently with a
reduction in wolverine records for the Great Lakes region in the
contiguous United States (Aubry et al. 2007, pp. 2155-2156). Causes of
these changes are uncertain, but may be related to increased harvest,
habitat modification, or climate change (COSEWIC 2003, pp. 20-21; Aubry
et al. 2007, pp. 2155-2156; Slough 2007, pp. 77-78). Analysis supports
climate change as a contributing factor to declines in southern
Ontario, because snow conditions necessary to support wolverines do not
currently exist in the Great Lakes region of the contiguous United
States, and are marginal in southern Ontario (Aubry et al. 2007, p.
2154). It is not known if these snow
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conditions existed historically in the Great Lakes of the contiguous
United States, however, the small number of wolverine records from this
area suggests that they did not. It is possible that suitable snow
conditions did reach further south in eastern Canada in 1850 than they
do today, making wolverine dispersal attempts from Canada to the Great
Lakes region of the contiguous United States more likely than they are
now. Wolverines occurred historically on Vancouver Island and have been
given status as a separate subspecies by some (Hall 1981, p. 109). The
Vancouver Island population is now regarded as possibly extirpated; no
sightings have occurred since 1992 (COSEWIC 2003, p. 18).
Wolverines in western Canada and Alaska appear to persist
everywhere that habitat and climate conditions are suitable (COSEWIC
2003, pp. 13-21; Aubry et al. 2007, pp. 2152-2155; Slough 2007, p. 79;
Copeland et al. 2010, Figure 2). Throughout this area, wolverines are
managed by regulated harvest at the Provincial and State level.
Population estimates for Canada and Alaska are rough because no
wolverine surveys have taken place at the State or Provincial scale.
However, the population in western Canada is estimated to include
approximately 15,089 to 18,967 individuals (COSEWIC 2003, p. 22). The
number of wolverines in Alaska is unknown, but they appear to exist at
naturally low densities in suitable habitats throughout Alaska (Alaska
Department of Fish and Game 2004, pp. 1-359). We have no information to
indicate that wolverine populations have been reduced in numbers or
geographic range in Alaska.
The Complexity of Geographic Range Delineation
Delineating wolverine historical and present range is inherently
difficult for several reasons. Wolverines tend to live in remote and
inhospitable places away from human populations where they are seldom
encountered, documented, or studied. Wolverines naturally occur at low
population densities and are rarely and unpredictably encountered where
they do occur. Wolverines often move long distances in short periods of
time, when dispersing from natal ranges, into habitats that are
unsuitable for long-term survival (Aubry et al. 2007, p. 2147; Moriarty
et al. 2009, entire; Inman et al. 2009, pp. 22-28; Brian 2010, p. 3).
Such movements make it difficult to distinguish with certainty between
occurrence records that represent established populations and those
that represent short-term occupancy or exploratory movements without
the potential for establishment of home ranges, reproduction, and
eventually populations. These natural attributes of wolverines make it
difficult to precisely determine their present range, or trends in
range expansion or contraction that may have occurred in the past.
Therefore, we must be cautious and use multiple lines of evidence when
trying to determine where past wolverine populations occurred.
Throughout the remainder of this finding, we focus on the use of
verifiable and documented wolverine occurrence records to define
historic and present range because we have determined that these
records constitute the best scientific information available on the
past and present distribution of wolverines (See Aubry et al. 2007, p.
2148). Verifiable records are records supported by physical evidence
such as museum specimens, harvested pelts, DNA samples, and diagnostic
photographs. Documented records are those based on accounts of
wolverines being killed or captured. Use of only verifiable and
documented records avoids mistakes of misidentification often made in
eyewitness accounts of visual encounters. Visual-encounter records
often represent the majority of occurrence records for elusive forest
carnivores, and their inherently high rate of misidentification of the
species involved can result in wildly inaccurate conclusions about
species occurrence (McKelvey et al. 2008, entire). The paper by Aubry
et al. (2007, entire) utilized only verifiable and documented records
to investigate wolverine distribution through time. This paper is the
only available comprehensive treatment of these distribution patterns
that attempts to distinguish between records that represent resident
animals versus animals that have dispersed outside of suitable habitat.
For these reasons we believe that Aubry et al. (2007, entire)
represents the best available summary of wolverine occurrence records
in the contiguous United States at this time. Since the publication of
Aubry et al. (2007, entire), verified records of wolverine have also
been documented in Colorado and California, which we will describe in
greater detail below.
Aubry et al. (2007, entire) used verifiable and documented records
from museum collections, literature sources, and State and Federal
institutions to trace changes in geographic distribution of wolverines
in the historic record. They then used an overlay of suitable wolverine
habitats to further refine which records represent wolverines in
habitats that may support residency, and by extension, populations, and
which records likely represent wolverines outside the range of suitable
habitats, so called ``extralimital'' records. Aubry et al.'s (2007,
entire) focus on verifiable and documented records corrected past
overly broad approaches to wolverine range mapping (Nowak 1973, p. 22;
Hall 1981, p. 1009; Wilson 1982, p. 644; Hash 1987, p. 576) that used a
more inclusive but potentially misleading approach when dealing with
occurrence records. Many of the extralimital records used in these
publications represent individuals dispersing from natal ranges that
ended up in habitats that cannot support wolverines, and the use of
this data to determine the historic geographic range of wolverines
results in gross overestimation of the area that can actually be used
successfully by wolverines for the establishment of populations.
Subsequent to publication of Aubry et al. (2007, entire), Copeland et
al. (2010, entire) further refined our understanding of wolverine
habitat needs and corroborated the approach of Aubry et al. (2007,
entire).
We agree with Aubry et al. (2007, p. 2149) that the most
appropriate method to determine the current and historic range of
wolverines is to use a combination of occurrence records and habitat
suitability, along with other information, such as documented
successful reproduction events, that indicate where reproductive and
potentially self-sustaining populations may occur. We also generally
agree with their conclusions about the historic and current range of
the species. We believe that the species' range is the area that may
support viable populations, and does not include extralimital
occurrences outside of habitat that is likely to support wolverine
life-history needs. Areas that can support wolverine populations may be
referred to as potential ``source'' populations because they provide
surplus individuals through reproduction beyond what is needed for
replacement. Areas that do not have the habitat to support viable
populations may be referred to as population ``sinks'' because
wolverines may disperse to these areas and remain for some time, but
will either die there without reproducing, leave the area in search of
better habitat conditions, or may actually reproduce, but at a rate
lower than that needed for replacement of individuals lost to mortality
or emigration, leading to eventual population extinction. For a widely
dispersing species like wolverines, we expect many locality records to
represent dispersers into sink habitats. The value to the population
(and thus
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the DPS) of these dispersers in sink habitat is unclear; however, it is
likely that most dispersers into sink habitats will be lost to the
population unless they are able to move back into source habitats.
Therefore, it is our belief that population sink areas, here defined as
places where wolverines may be found but where habitat is not suitable
for long-term occupancy and reproduction, do not represent part of the
species historic range and have little conservation value for the DPS,
other than possibly serving as way-stations for attempted dispersers as
they search for suitable habitats. This approach to defining historic
range results in reducing the bias of extralimital dispersers and
concentrates conservation attention on areas capable of maintaining
populations, and is more in keeping with the intentions of the Act,
than broader depictions of geographic range.
Aubry et al. (2007, pp. 2147-2148) divided records into
``historical'' (recorded prior to 1961), ``recent'' (recorded between
1961 and 1994), and ``current'' (recorded after 1994). Historical
records occurred before systematic surveys. Historical records
encompass the time during which wolverine numbers and distribution were
hypothesized to be at their highest (prior to European settlement) and
also at their lowest (early 20th Century) (Wright and Thompson 1935;
Grinnell et al. 1937; Allen 1942; Newby and Wright 1955, all as cited
in Aubry et al. 2007, p. 2148). The recent time interval covers a
hypothesized population expansion and rebound from the early 20th
Century low. Current records offer the most recent evidence available
for wolverine occurrences and potential populations. We believe all
occurrence records must be individually analyzed in light of their
context in terms of habitat conditions conducive to wolverine
population establishment and whether or not they occur clustered with
other records, which might indicate that populations have historically
occurred in the area. The authors of Aubry et al. (2007) did such an
analysis as they compiled their records.
Wolverine Distribution
Of 729 mappable records (those records with precise location
information) compiled by Aubry et al. (2007, p. 2150), 188 were from
the historical time interval (see Figure 1). We assessed the
historical, recent, and current distribution data for each of the
regions below to determine the likelihood of the presence of historical
populations (rather than extralimital dispersers). The discussion below
draws heavily from both Aubry et al. (2007, entire) and Copeland et al.
(2010, entire).
Table 1--Wolverine Records From Three Time Periods From Aubry et al. 2007.
[Numbers Represent Total Documented and Verifiable Records With the Subset of Those Records That Were Verifiable
in Parentheses]
----------------------------------------------------------------------------------------------------------------
Historical (< Recent (1961- Current (>
1964) 1994) 1994)
----------------------------------------------------------------------------------------------------------------
Northeast....................................................... 13 (1) 0 0
Upper Midwest................................................... 4 (2) 0 0
Great Lakes..................................................... 36 (4) 1 0
Central Great Plains............................................ 71 * (2) 1 0
Rocky Mountains................................................. 147 (45) 332 (283) 215 (210)
Pacific Coast................................................... 89 (14) 23 (15) 7
-----------------------------------------------
Totals...................................................... 362 (68) 357 (298) 222 (210)
----------------------------------------------------------------------------------------------------------------
* 35 records from a single source (the journals of Alexander Henry).
Northeast and Upper Midwest--The low number of records and
scattered nature of their distribution combined with a lack of suitable
habitat indicate that wolverines were likely only occasional transients
to the area and not present as a reproducing population after 1800.
Great Lakes--The lack of large numbers of verifiable records in
this area of relatively high human population density and the lack of
suitable habitat suggests that wolverines did not exist in this area as
a viable population after 1900. Widely scattered records generally
before 1900, with an occasional record after that year, suggest that if
a reproducing population existed in the Great Lakes, it predated 1900,
and that post-1900 records represent dispersal from a receding Canadian
population. Wolverine distribution in Ontario, Canada, appears to have
receded north from the Great Lakes region since the 1800s, and
currently wolverines occupy only the northern portion of the province,
a distance of over 400 miles from the U.S. border (COSEWIC 2003, p. 9).
The pattern of record distribution illustrated in Aubry et al. (2007,
p. 2152) is consistent with what would be expected if those records
were of dispersing individuals from a Canadian population that receded
progressively further north into Canada after 1900, possibly due to
natural climate changes.
Central Great Plains--The lack of precise locality records and
suitable habitat from the Great Plains States leads us to conclude that
reproducing populations of wolverines did not historically inhabit this
area. Thirty-five of thirty-six records from North Dakota are from the
journals of a single fur trader (see Table 1), and it is not clear that
the records represent actual collection localities or are localities
where trades or shipments occurred (Aubry 2007, pers. comm.). Given the
habitat relationships of wolverines (e.g., Copeland et al. 2010, Figure
1), it is unlikely that these records represent established wolverines
or that this area was in any way wolverine habitat.
Rocky Mountains--Five Rocky Mountains States (Idaho, Montana,
Wyoming, Colorado, and Utah) contained numerous wolverine records.
Records with precise locality information appear to coalesce around
several areas that may have been population centers, such as central
Colorado, the greater Yellowstone region, and northern Idaho-
northwestern Montana. The large number of verifiable and documented
records for this region, along with the suggestion of population
centers or strongholds, suggests that wolverines existed in reproducing
populations throughout much of the Rocky Mountains during the
historical time interval. The lack of records for Colorado and Utah
after 1921 suggests that the southern Rocky Mountain population of
wolverines was extirpated in the early 1900s, concurrent with
[[Page 78035]]
widespread systematic predator control by government agencies and
livestock interests. The northern Rocky Mountain population (north of
Wyoming) was reduced to historic lows or possibly even extirpated
during the early 1900s, and then increased dramatically in the second
half of the 1900s (see Table 1) as predator control efforts subsided
and trapping regulations became more restrictive (Aubry et al. 2007, p.
2151). This increase likely indicates a population rebound from
historic lows in this period.
Wolverine records from 1995 to 2005 indicate that wolverine
populations currently exist in the northern Rocky Mountains (see Table
1). Legal trapping in Montana in the recent past removed an average of
10.5 individuals from this population each year (Montana Department of
Fish, Wildlife, and Parks 2007, p. 2), and harvest mortality has been
reduced due to regulatory changes in 2008 (Montana Department of Fish,
Wildlife and Parks 2008, p. 8). Populations in British Columbia and
Alberta, Canada, are extant (COSEWIC 2003, pp. 18-19), and may have
been a source of surplus wolverines to the contiguous U.S. population
during population lows. Recently, a male wolverine moved on its own
from the southern Greater Yellowstone Area of Wyoming into the southern
Rocky Mountains of Colorado where it still persisted as of August 2010
(Inman et al. 2009, pp. 22-26; Inman 2010, pers. comm.). This attempted
dispersal event is the first verified wolverine occurrence in Colorado
since 1919 and may represent a continuation of the wolverine expansion
in the Rocky Mountains detailed above. It is possible that other
wolverines have travelled to the southern Rocky Mountains and have
remained undetected. There is no evidence that Colorado currently hosts
a wolverine population or that female wolverines have made, or are
likely to make, similar movements.
Pacific Coast--Historically, wolverines occurred in two population
centers in the North Cascades Range and the Sierra Nevada. These areas
are separated by an area with no historic records (southern Oregon and
northern California), indicating that the historical distribution of
wolverines in this area is best represented by two disjunct populations
rather than a continuous peninsular extension from Canada. This
conclusion is supported by genetic data indicating that the Sierra
Nevada and Cascades wolverines were separated for at least 2,000 years
prior to extirpation of the Sierra Nevada population (Schwartz et al.
2007, p. 2174).
Only one Sierra Nevada record exists after 1930, indicating that
this population was likely extirpated in the first half of the 1900s
concurrent with widespread systematic predator control programs. In
2008, a male wolverine was discovered in the Sierra Nevada Range of
California, the first verified record from California since 1922
(Moriarty et al. 2009, entire). Genetic testing revealed that this
wolverine was not a descendant of the endemic Sierra Nevada wolverine
population, but was likely derived from wolverines in the Rocky
Mountains (Moriarty et al. 2009, p. 159). This attempted dispersal
event may represent a continuation of the wolverine expansion in the
contiguous United States as detailed above. Other wolverines may have
traveled to the Sierra Nevada and remain undetected. There is no
evidence that California currently hosts a wolverine population or that
female wolverines have made or are likely to make similar dispersal
movements.
Wolverines were likely extirpated from the North Cascades in the
early 20th century and then recently recolonized from Canada.
Currently, a small population persists in this area (Aubrey et al.
2009, entire). The Northern Cascades population may be connected with,
and is possibly dependent on, the larger Canadian population for future
expansion and long-term persistence.
Summary of Wolverine Distribution
Historical wolverine records were found across the northern tier of
the contiguous United States with convincing evidence of wolverine
populations in the northern and southern Rocky Mountains, Sierra Nevada
Mountains, and North Cascades Mountains (Aubry et al. 2007, p. 2152).
Currently, wolverines appear to be distributed as functioning
populations in two regions in the contiguous United States: The North
Cascades in Washington, and the northern Rocky Mountains in Idaho,
Montana, and Wyoming. Wolverines were likely extirpated, or nearly so,
from the entire contiguous United States in the first half of the 20th
Century (Aubry et al. 2007, Table 1). The available evidence suggests
that, in the second half of the 20th Century and continuing into the
present time, wolverine populations have expanded in the North Cascades
and the northern Rocky Mountains, but that populations have not been
reestablished in the Sierra Nevada Range or the southern Rocky
Mountains. We conclude that the current range of the species in the
contiguous United States includes the North Cascades Mountains, the
northern Rocky Mountains, the southern Rocky Mountains, and the Sierra
Nevada Mountains, but that reestablishment of populations in the
southern Rocky Mountains and Sierra Nevada has not yet occurred.
We also conclude that wolverines either did not exist as
established populations, or were extirpated prior to settlement and the
compilation of historical records, in the Great Lakes region, possibly
due to climate changes that occurred through the 1800s and 1900s. The
Great Lakes region lacks suitable wolverine habitat, and suitable
habitat does not appear to exist in adjacent Canada (Copeland et al.
2010, Figure 1). The widely scattered records from this region are
consistent with dispersing individuals from a Canadian population that
receded north early in the 1800s. We cannot rule out the possibility
that wolverines existed as established populations prior to the onset
of trapping in this area, but we have no reliable evidence that they
did.
No reliable evidence in the historical records indicates that
wolverines were ever present as established populations in the Great
Plains, Midwest, or Northeast.
Habitat Relationships and Wolverine Distribution
Deep, persistent, and reliable spring snow cover (April 15 to May
14) is the best overall predictor of wolverine occurrence in the
contiguous United States (Aubry et al. 2007, pp. 2152-2156; Copeland et
al. 2010, entire). Deep persistent snow correlates well with wolverine
year-round habitat use across wolverine distribution in North America
and Eurasia at both regional and local scales (Copeland et al. 2010,
entire). It is uncertain why spring snow cover so accurately predicts
wolverine habitat use; however, it is likely related to wolverines'
need for deep snow during the denning period, and also wolverines'
physiological requirement for year-round cold temperatures (Copeland et
al. 2010, pp. 242-243). Snow cover during the denning period is
essential for successful wolverine reproduction range-wide (Hatler
1989, p. iv; Magoun and Copeland 1998, p. 1317; Inman et al. 2007c, pp.
71-72; Persson 2007; Copeland et al. 2010, p. 244). Wolverine dens tend
to be in areas of high structural diversity such as logs and boulders
with deep snow (Magoun and Copeland 1998, p. 1317; Inman et al. 2007c,
pp. 71-72; Persson 2007, entire). Reproductive females dig deep snow
tunnels to reach the protective structure provided by logs and
boulders. This behavior presumably protects the
[[Page 78036]]
vulnerable kits from predation by large carnivores, including other
wolverines (Pulliainen 1968, p. 342; Zyryanov 1989, pp. 3-12), but may
also have physiological benefits for kits by buffering them from
extreme cold, wind, and desiccation (Pullianen 1968, p. 342,
Bj[auml]rvall et al. 1978, p. 23). Wolverines live in low-temperature
conditions and appear to select habitats in part to avoid high summer
temperatures (Copeland et al. 2010, p. 242). Wolverine distribution is
likely affected by climatic conditions at two different scales.
Wolverines require deep persistent snow for denning, and this likely
determines where wolverine populations can be found at the grossest
range-wide scale (Copeland et al. 2010, p. 244). At smaller scales,
wolverines likely select habitats to avoid high summer temperatures.
These cool habitats also tend to retain snow late into spring, leading
to wolverines' year-round association with areas of persistent spring
snow (Copeland et al. 2010, p. 244).
All of the areas in the contiguous United States for which good
evidence of persistent wolverine populations (either present or
historic) exists (i.e., North Cascades, Sierra Nevada, northern and
southern Rocky Mountains) contain large and well-distributed areas of
deep snow cover that persists through the wolverine denning period
(Brock et al. 2007, pp. 36-53; Aubry et al. 2007, p. 2154; Copeland et
al. 2010, Figure 1). The Great Plains, Great Lakes, Midwest, and
Northeast lack the spring snow conditions and low summer temperatures
thought to be required by wolverines for successful reproduction and
year-round occupancy (Aubry et al. 2007, p. 2154; Copeland et al. 2010,
Figure 1). The lack of persistent spring snow conditions in the Great
Plains, Great Lakes, Midwest, and Northeast supports the exclusion of
these areas from the current range of wolverines. Whether wolverines
once existed as established populations in any of these regions is
uncertain, but the current climate appears to preclude their presence
as reproducing populations now, and the sparse historical record of
wolverine presence in this area makes historic occupation of these
areas by wolverine populations doubtful. It is our conclusion that the
ecosystem that supports wolverines does not exist in these areas
currently, and may never have existed in the past.
Large areas of habitat with characteristics suitable for wolverines
still occur in the southern Rocky Mountains and Sierra Nevada, despite
the extirpation of wolverines from those areas (Aubry et al. 2007, p.
2154, Brock et al. 2007, p. 26; Copeland et al. 2010, Figure 1).
Wolverine extirpations in these areas were coincident with systematic
predator eradication efforts in the early 1900s, which have been
discontinued for many years. Each of these areas has received at least
one and possibly more migrants from adjacent populations in the
northern Rocky Mountains; however, there is no evidence that females
have migrated to these areas or that populations of wolverines exist in
them (Aubry et al. 2007, Table 1; Moriarty et al. 2009, entire; Inman
et al. 2009, entire).
We conclude that areas of wolverine historical occurrence can be
placed in one of three categories: (1) Areas where wolverines are
extant as reproducing and potentially self-sustaining populations
(North Cascades, northern Rocky Mountains); (2) areas where wolverines
historically existed as reproducing and potentially self-sustaining
populations prior to human-induced extirpation, and where
reestablishment of those populations is possible given current habitat
condition and management (the Sierra Nevada Mountains in California and
southern Rocky Mountains in Colorado, New Mexico, Wyoming, and Utah);
and (3) areas where historical presence of wolverines in reproducing
and potentially self-sustaining populations is doubtful, and where the
current habitat conditions preclude the establishment of populations
(Great Plains, Midwest, Great Lakes, and Northeast). We, therefore,
consider the current range of wolverines to include suitable habitat in
the North Cascades of Washington and possibly Oregon, the northern
Rocky Mountains of Idaho, Wyoming, and Montana, the southern Rocky
Mountains of Colorado, Utah, and Wyoming, and the Sierra Nevada of
California. We here include the Sierra Nevada and southern Rocky
Mountains in the current range of wolverines despite the probability
that functional populations do not exist in these areas. They are
included due to the known existence of one individual in each area and
the possibility that more, as yet undetected, individuals inhabit these
areas.
Distinct Population Segment
Pursuant to the Act, we must consider for listing any species,
subspecies, or, for vertebrates, any Distinct Population Segment (DPS)
of these taxa, if there is sufficient information to indicate that such
action may be warranted. To interpret and implement the DPS provision
of the Act and Congressional guidance, the Service and the National
Marine Fisheries Service published, on February 7, 1996, an interagency
Policy Regarding the Recognition of Distinct Vertebrate Population
Segments under the Act (61 FR 4722). This policy addresses the
recognition of DPSs for potential listing actions. The policy allows
for more refined application of the Act that better reflects the
biological needs of the taxon being considered, and avoids the
inclusion of entities that do not require its protective measures.
Under our DPS policy, three elements are considered in a decision
regarding the status of a possible DPS as endangered or threatened
under the Act. These are applied similarly for additions to the list of
endangered and threatened species, reclassification, and removal from
the list. They are: (1) Discreteness of the population segment in
relation to the remainder of the taxon; (2) the biological or
ecological significance of the population segment to the taxon to which
it belongs; and (3) the population segment's conservation status in
relation to the Act's standards for listing (i.e., whether the
population segment is, when treated as if it were a species or
subspecies, endangered or threatened). Discreteness refers to the
degree of isolation of a population from other members of the species,
and we evaluate this based on specific criteria. If a population
segment is considered discrete, we must consider whether the discrete
segment is ``significant'' to the taxon to which it belongs by using
the best available scientific and commercial information. If we
determine that a population segment is both discrete and significant,
we then evaluate it for endangered or threatened status based on the
Act's standards. The DPS evaluation in this finding concerns the
segment of the wolverine species occurring within the 48 States,
including the northern and southern Rocky Mountain physiographic
provinces, Sierra Nevada Range, and North Cascades Range.
Distinct Population Segment Analysis for Wolverine in the Contiguous
United States
Analysis of Discreteness
Under our DPS Policy, a population segment of a vertebrate species
may be considered discrete if it satisfies either one of the following
conditions: (1) It is markedly separated from other populations of the
same taxon as a consequence of physical, physiological, ecological, or
behavioral factors (quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation); or (2) it is
delimited by international governmental boundaries within which
[[Page 78037]]
differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act (inadequacy of
existing regulatory mechanisms). The wolverine within the contiguous
United States meets the second DPS discreteness condition because of
differences in conservation status as delimited by the Canadian-U.S.
international governmental boundary.
Discreteness Based on the International Border--Differences in
Conservation Status
We find that differences in conservation status of the wolverine
between the United States and Canada are substantial and significant in
light of section 4(a)(1)(D) of the Act. In the remaining current range
in Canada-Alaska, wolverines exist in well-distributed, interconnected,
large populations. Conversely, wolverine populations in the remaining
U.S. range appear to be at numbers so low that their continued
existence could be at risk, especially as considered in light of the
five threat factors discussed below. These risks come from three main
factors: (1) Small total population size; (2) effective population size
below that needed to maintain genetic diversity and demographic
stability; and (3) the fragmented nature of wolverine habitat in the
contiguous United States that results in smaller, isolated ``sky
island'' patches separated by unsuitable habitats. It is apparent that
maintaining wolverines within their native range in the contiguous
United States into the future is likely to require regulatory
mechanisms that are not currently in place. These three factors are
explained in more detail below.
The total population sizes for Canada-Alaska and the contiguous
United States differ by more than an order of magnitude. The contiguous
U.S. population likely numbers approximately 250 to 300 individuals
(Inman 2010b, pers. comm.). This contrasts with western Canada, where
wolverine populations are estimated at 15,089 to 18,967 individuals
(COSEWIC 2003, p. 22). Wolverine population size in Alaska is unknown;
however, the average annual harvest exceeds 500 individuals and the
population does not appear to be in decline (Alaska Department of Fish
and Game 2004, entire), indicating that the population is likely to
number over ten thousand individuals (calculated using demographic data
in Lofroth and Ott 2007, pp. 2196-2198; assumes sustainable harvest).
The difference in total population size coincides with the
international boundary between the contiguous United States and Canada.
Wolverine populations number 2,089-3,567 in British Columbia and 1,500-
2,000 in Alberta (COSEWIC 2003, p. 22), the two provinces immediately
adjacent to the contiguous U.S. wolverine population. The difference in
total population sizes is significant because critically small
populations such as those in the contiguous United States face higher
extinction risk than large ones such as the Canada-Alaska population.
Therefore, the contiguous U.S. population is more vulnerable to
extinction, and thus of poor conservation status, relative to the more
secure Canada-Alaska population.
Wolverines in Canada's eastern provinces are listed under the
Species at Risk Act of Canada. Wolverines in the eastern provinces
appear to have been extirpated by the early 20th century (COSEWIC 2003,
p. 20). There is a general lack of reliable historic information on
wolverines in this area, and significant doubt exists about whether a
population ever occurred there historically (COSEWIC 2003, p. 20). For
the purposes of this finding, we considered the Canadian wolverine
population to include only wolverines from Ontario west to the Pacific
coast and Alaska, and assumed that wolverines in eastern Canada were
either extirpated or are at such low numbers as not to be part of a
functioning population. It is our determination that the conservation
status of the eastern population, if it does indeed exist, is not
relevant to the discreteness analysis for this DPS for the following
reasons: (1) If wolverines currently reside in the eastern Canadian
Provinces, they are likely disjunct from wolverines in western Canada
(COSEWIC 2003, Figure 3); and (2) there is significant doubt that
wolverine populations existed in this part of Canada historically, so
the current lack of evidence of a population may not represent a
degradation of species status in this area (COSEWIC 2003, pp. 20-21).
The second substantial difference in wolverine status between the
contiguous United States and Canada is reflected in the size of the
effective populations. Population ecologists use the concept of a
population's ``effective'' size as a measure of the proportion of the
actual population that contributes to future generations (for a review
of effective population size, see Schwartz et al. 1998, entire). In a
population where all of the individuals contribute offspring equally,
effective population size would equal true population size. For
populations where contribution to the next generations is often
unequal, effective population size will be smaller than the true or
``census'' population size. The smaller the effective population size,
the more reproduction is dominated by a few individuals. Effective
population size is important because it determines rates of loss of
genetic variation, fixation of deleterious alleles and the rate of
inbreeding. Populations with small effective population sizes show
reductions in population growth rates and increases in extinction
probabilities (Leberg 1990, p. 194; Jimenez et al. 1994, pp. 272-273;
Newman and Pilson 1997, p. 360; Saccheri et al. 1998, p. 492; Reed and
Bryant 2000, p. 11; Schwartz and Mills 2005, p. 419; Hogg et al. 2006,
p. 1495, 1498; Allendorf and Luikart 2007, pp. 338-342). Franklin
(1980, as cited in Allendorf and Luikart 2007, p. 359) proposed an
empirically based rule suggesting that for short-term (a few
generations) maintenance of genetic diversity, effective population
size should not be less than 50. For long-term (hundreds of
generations) maintenance of genetic diversity, effective population
size should not be less than 500 (for appropriate use of this rule and
its limitations see Allendorf and Luikart 2007, pp. 359-360). Others
suggest that even higher numbers are required to ensure that
populations remain viable, suggesting that long-term connectivity to
the reservoir of genetic resources in the Canadian population of
wolverines will be required (Traill et al. 2010, p. 32).
Wolverine effective population size in the largest extant
population in the contiguous United States is exceptionally low
(Schwartz personal communication 2007, entire) and is below what is
thought necessary for short-term maintenance of genetic diversity.
Effective population size for wolverines in the Rocky Mountains
averaged 39 (Schwartz personal communication 2007, entire) (this study
excluded the small population from the Crazy and Belt Mountains
(hereafter ``CrazyBelts'') as they may be an isolated population, which
could bias the estimate using the methods of Tallmon et al. (2007,
entire)). Measures of the effective population sizes of the other
populations in the contiguous United States have not been completed,
but given their small census sizes, their effective sizes are expected
to be smaller than for the northern Rocky Mountain population. Thus,
wolverine effective population sizes are very low. For comparison,
estimates of wolverine effective population size are bracketed by
critically endangered species like the black-footed ferret (4.10)
(Wisely et al.
[[Page 78038]]
2007, p. 3) and ocelots (2.9 to 13.9) (Janecka et al. 2007, p. 1), but
substantially smaller than estimates for the Yellowstone Grizzly bear
(greater than 100), which has reached the level of recovery under the
Act (Miller and Waits 2003, p. 4338). Therefore, we conclude that
effective population size estimates for wolverines do not suggest that
populations are currently critically endangered, but they do suggest
that populations are low enough that they could be vulnerable to loss
of genetic diversity, and may require intervention in the future to
remain viable.
The concern with the low effective population size is highlighted
in recent research that determined that, absent immigration, at least
400 breeding pairs would be necessary to sustain long-term genetic
viability of the contiguous U.S. wolverine population (Cegelski et al.
2006, p. 197). However, the entire population is likely 250-300 (Inman
2010b, pers. comm.), with a substantial number of these being
nonbreeding subadults. Furthermore, the U.S. population appears to be
split into at least five smaller subpopulations (Northern Cascades,
CrazyBelts, Idaho, Greater Yellowstone Ecosystem, and Northern Montana)
that are semi-isolated from each other, meaning that genetic exchange
does not occur frequently enough to prevent genetic drift (changes in
genetic composition due to random sampling in small populations) and
loss of genetic diversity (Cegelski et al. 2006, p. 206) further
reducing the effective population size. Based on available scientific
and commercial information, it does not appear that any of the
wolverine populations that historically existed in the contiguous
United States would have had effective population sizes approaching 400
animals. Therefore, it is likely that connectivity to Canadian
populations to the north would have been necessary to maintain genetic
diversity in these populations prior to European settlement.
The concern that low effective population size may result in
negative effects is already being realized for the contiguous U.S.
population of wolverine. Genetic drift has occurred in the remaining
populations in the contiguous United States: wolverines here contain 3
of 13 haplotypes (sets of closely linked genetic markers that are
inherited together) found in Canadian populations (Kyle and Strobeck
2001, p. 343; Cegelski et al. 2003, pp. 2914-2915; Cegelski et al.
2006, p. 208; Schwartz et al. 2007, p. 2176; Schwartz et al. 2009, p.
3229). The haplotypes found in these populations are a subset of those
in the larger Canadian population, indicating that genetic drift had
caused a loss of genetic diversity. A single haplotype dominates the
northern Rocky Mountain wolverine population, with 71 of 73 wolverine
sampled expressing that haplotype (Schwartz et al. 2007, p. 2176). The
reduced number of haplotypes indicates not only that genetic drift is
occurring, but also that there is some level of genetic separation; if
these populations were freely interbreeding, they would share more
haplotypes. The reduction of haplotypes is likely a result of small
population size and the fragmented nature of wolverine habitat in the
United States and is consistent with an emerging pattern of reduced
genetic variation at the southern edge of the range documented in a
suite of boreal forest carnivores (Schwartz et al. 2007, p. 2177).
Whether or not the wolverine population in the contiguous United States
has suffered any deleterious effects due to this reduction in genetic
diversity is unknown. However, based on principles of conservation
genetics, we do expect that reduced genetic diversity would make this
population more vulnerable to other threats due to reduced genetic
resiliency and reduced ability to adapt to change (Allendorf and
Luikart 2007, pp. 338-342).
No effective population size estimate exists for populations in
Canada or Alaska; however, because of the large and contiguous nature
of the population and the relatively high genetic diversity in Canada
and Alaska, there is a reasonable scientific basis to conclude that the
effective population size is large enough that it is not a cause for
conservation concern. None of the Canadian or Alaskan populations
tested show signs of genetic drift or inbreeding. This information
indicates that the population does not have a low effective population
size.
Reduced genetic diversity and low effective population sizes result
in high extinction risk in animal populations (Frankham 1995, p. 795).
The fragile nature of wolverine populations in the contiguous United
States contrasts with Canada and Alaska where wolverines are relatively
abundant and exist in habitats with a high level of connectivity
(COSEWIC 2003, p.8; Slough 2007, p. 78).
The third substantial difference in wolverine status between the
contiguous United States and Canada is reflected by the amount and
distribution of available habitat for the species. Habitat in the
contiguous United States consists of small isolated ``islands'' of
high-elevation alpine habitats separated from each other by low valleys
of unsuitable habitats. Habitat islands are represented by areas
containing spring snow (Copeland et al. 2010, Figure 2). Wolverine
range in the contiguous United States is characterized by isolated
mountain habitats dissected by lower-elevation valleys, while habitat
in adjoining Canada comprises mostly large blocks of contiguous habitat
(Copeland et al. 2010, Figure 2; Copeland 2010, pers. comm.).
Wolverines occupy habitat at high elevations, generally above 2,100 m
(6,888 ft), in the mountains of the contiguous United States. The
intervening valleys in this area range from 975 m to 1,500 m (3,198 ft
to 4,920 ft), and are dominated by ecosystems that are unsuitable for
long-term wolverine presence, but do serve as routes for wolverine
movement between suitable habitat patches. Intermountain valleys are
increasingly becoming the sites of human residential and commercial
developments and transportation corridors. The large distances between
suitable wolverine habitats results in wolverines existing on an
archipelago of suitable habitats in a sea of unsuitable habitat. The
low population density and genetic diversity of wolverines in this area
requires that exchange of individual wolverines between islands of
habitat occurs to avoid inbreeding or local extinction due to
demographic stochasticity.
Wolverine populations in the Canadian Rocky Mountains also exist on
habitat islands, but the islands are much larger, so that exchange of
individuals is less critical for demographic and genetic stability.
Further north in Canada, where cold snowy conditions occur at lower
elevations, wolverines inhabit lower elevations and valley bottom
habitats (COSEWIC 2003, pp. 7-8). In the far north of Canada, wolverine
habitat extends into low-elevation valleys and the vast expanses of
low-elevation boreal forest and tundra. For these reasons, exchange of
wolverines between habitat islands in the Canadian Rocky Mountains is
both more likely to occur and less critical for the long-term
maintenance of those populations.
In the contiguous United States, wolverines must cross unsuitable
habitats to achieve connectivity among subpopulations, which is
required to avert further genetic drift and loss of genetic diversity
(Kyle and Strobeck 2002, p. 1148; Cegelski et al. 2006, pp. 208-209;
Schwartz et al. 2009, p. 3230). The highly fragmented nature of the
habitat in the contiguous United States contributes to the low
effective population size for wolverines in this area, making the
continued persistence of the population precarious relative to the
Canadian-Alaskan population.
[[Page 78039]]
Habitats in Canada and Alaska exist in larger contiguous blocks that
have few or no impediments to demographic or genetic connectivity with
peripheral smaller blocks (Copeland et al. 2010, Figure 2). The
fragmented nature and distribution of wolverine habitat in the
contiguous United States results in a population that is highly
vulnerable to extirpation because of lack of connectivity between
subpopulations, it also makes them more vulnerable to external threats
such as those analyzed under the five threat factors below.
Conservation status of wolverines in the contiguous United States
differs significantly with that of the Canada-Alaska population. The
Canada-Alaska population is large, well-connected, and exists in large
blocks of contiguous habitat. In contrast, the population in the
contiguous United States is small in total size and is fragmented on
small patches of suitable habitat that are separated by large areas of
unsuitable habitat. These differences result in a Canada-Alaska
population that is robust and better able to respond to habitat
changes, while the contiguous United States population is vulnerable to
changes in habitat or management. We believe that the differences in
conservation status between the contiguous United States and Canada are
significant in light of section 4(a)(1)(D) of the Act (inadequacy of
existing regulatory mechanisms) because they reveal that the existing
mechanisms in Canada are sufficient to maintain wolverine, while in the
United States, the existing regulatory mechanisms are not sufficient to
address the biological conservation concerns.
Legal Status Conveyed by National, State, and Provincial Governments
The United States currently confers no Federal status on the
wolverine. Each State regulates the species relative to its existing
populations. In Washington, the wolverine is listed as State Endangered
(Washington Department of Fish and Wildlife 2010, entire). Idaho and
Wyoming designate it as a protected nongame species (Idaho Fish and
Game 2010, p. 4; Wyoming Game and Fish 2005, p. 4), and Montana
regulates it as a furbearer (Montana Department of Fish, Wildlife, and
Parks 2010, entire). Oregon, while currently not considered to have any
individuals other than possible unsuccessful dispersers, has a closed
season on trapping of wolverines. California and Colorado currently
each have only one confirmed wolverine, and the States do not allow
harvest.
The Canadian Government has listed its Eastern population of
wolverine as Endangered under the Species at Risk Act (SARA) in Quebec
and Labrador, where it may be extirpated due to trapping and hunting
and declining caribou herds (Government of Canada 2010, entire).
Because wolverines appear to have been extirpated from this area since
the early part of the century and their historical status as a viable
population is uncertain, we do not consider it to be in the current
range, and thus consider the species' status there not relevant to the
question of whether significant differences in status exist between the
two countries. The Western population of wolverines occurs in eight
Provinces, two of which (British Columbia and Alberta) are contiguous
to the wolverine range in the United States. This population in Canada
has no status under SARA, but has a designation of Special Concern
(Vulnerable) under the Committee on the Status of Endangered Wildlife
in Canada (COSEWIC) (Government of Canada 2010, entire), a status that
does not provide legal protections. British Columbia and Alberta have
Provincial species conservation lists, which are priority-setting tools
for establishing baseline ranks and conservation activities (Province
of British Columbia 2002, p. 1). Both Provinces include the wolverine
on their provincial ``blue list,'' indicating that it may be at risk
(Peterson 1997, p. 1), except on Vancouver Island where the wolverine
is possibly extirpated and is ``red listed'' (threatened, endangered,
or candidate; not harvested) (Lofroth and Ott 2007, p. 2193; Province
of British Columbia 2002, p. 2).
In our 2008 12-month finding, we determined that differences in
management status conveyed by the States and Provinces that regulate
wolverine management were not significantly different from each other,
as States and Provinces both allowed regulated harvest and there were a
variety of regulatory mechanisms in each. Regulatory status in the
Canadian Provinces and U.S. States regulatory status remains unchanged,
and we continue to find no significant difference between the legal
status of wolverines between Canada and the United States.
While similarities exist in the legal conservation statuses
bestowed on the wolverine in the four U.S. States where it currently
persists, and the two adjacent Canadian Provinces, the differences in
biological conservation status are significant and affect the future of
the species. In western Canada, the wolverine has no protection under
SARA; in the United States the wolverine currently has no status under
the Act. This allows piecemeal management by States and Provinces with
little regard for regional management directed at the continued
existence of the species in the contiguous United States.
Because British Columbia and Alberta are contiguous to a larger,
and more robust, portion of the wolverine's range in northwestern
Canada, documented declines in wolverine populations (likely due to
harvest levels) in the southern portions of both Provinces have not
raised the status of the species to a level of concern that would
result in its consideration for status under SARA (Lofroth and Krebs
2007, pp. 2164-2165; Lofroth and Ott 2007, p. 2193; Peterson 1997, pp.
4-5).
Differences in Control of Exploitation
Significant differences exist in control of exploitation between
the United States and Canadian wolverine populations. U.S. populations
are largely not harvested, with the exception of a carefully controlled
and very limited harvest in Montana; while in Canada, harvest is
widespread throughout the provinces within the current range. British
Columbia has a 3- to 4-month trapping season with no provincial quota,
while adjacent Washington considers the species State Endangered and
allows no trapping. Alberta allows a 3-month trapping season with
quotas in 6 of its 8 fur management zones for an annual average harvest
of 37 (zones 7 and 8 in Alberta are closed to trapping but are outside
the species' normal range and so the closure is of little conservation
consequence (Province of Alberta 2007, entire)), while adjacent Montana
allows up to a 2.5-month hunting and trapping season with a total quota
of 5 wolverines (maximum of 3 females).
Although we do not have comprehensive numbers of the annual
wolverine harvest in Canada, we have estimated a total annual harvest
of 719 animals (see Table 2) based upon the best information available
to us. Based on available information, we presume this to be an
underestimate, because it is based upon reported harvests, which, for
Canadian territories, likely accounts for only one-fifth to one-third
of the total harvest because of heavy unreported harvest and use by
local communities (Melchoir et al. 1987 as cited in Banci 1994, p.
101).
[[Page 78040]]
Table 2--Estimated Annual Wolverine Harvest in Canada
----------------------------------------------------------------------------------------------------------------
Estimated annual
Province or territory harvest Source
----------------------------------------------------------------------------------------------------------------
British Columbia.............................. 175 Lofroth and Ott, 2007, pp. 2196-2197.
Alberta....................................... 37 Province of Alberta 2006, p. 14.
Saskatchewan.................................. 10 COSEWIC 2007, Table 1
Manitoba...................................... 48 COSEWIC 2007, Table 1
Ontario....................................... 8 COSEWIC 2007, Table 1
Yukon......................................... 150 COSEWIC 2007, Table 1
Northwest Territories......................... 209 COSEWIC 2007, Table 1 \*\
Nunavut....................................... 82 COSEWIC 2007, Table 1 [caret]
-------------------
Total..................................... 719
----------------------------------------------------------------------------------------------------------------
\*\ Corrected to adjust for majority being unreported in pelt production statistics.
[caret] Corrected using Dumond and Krizan 2002 as cited in COSEWIC 2007 p. 17.
Based upon these numbers, we conservatively estimate that harvest
in Canada is a minimum of 4.7 percent of the population annually. This
estimate is nearly three times the amount of harvest in the United
States, which is approximately 5 animals of 300, or 1.6 percent. We
find that this nearly 300 percent difference is significant, because
the wolverine is sensitive to even small increases in mortality rates
(Squires et al. 2007, p. 2218). Human-caused mortality of wolverines is
likely additive to natural mortality due to the low reproductive rate
and relatively long life expectancy of wolverines (Krebs et al. 2004,
p. 499; Lofroth and Ott 2007, pp. 2197-2198; Squires et al. 2007, pp.
2218-2219).
These differences may be significant in light of section 4(a)(1)(D)
of the Act, because they show that regulatory mechanisms are necessary
in the United States and Canada to ensure that the contiguous U.S.
population continues to receive migrants from the genetically richer
Canadian population. However, the differences in control of
exploitation favor the U.S. population, which is the population that is
potentially at risk. In Canada, no such mechanisms are currently needed
to protect the species. About 15,000 to 19,000 wolverines occur in
western Canada where suitable habitat is plentiful (COSEWIC 2003, pp.
14-21). Because of this abundance of habitat, conservative management
and careful geographic control of harvest are not necessary to conserve
wolverines in western Canada. This situation contrasts with the
situation in the United States, where habitat is fragmented and
wolverine populations are limited to high elevations over portions of
four States (Washington, Idaho, Montana, and Wyoming). Because
differences in control of exploitation exist, but control favors the
at-risk population, we do not rely on control of exploitation to
establish discreteness.
Summary for Discreteness
The international boundary between Canada and the United States
currently leads to division of the control of exploitation and
conservation status of the wolverine. This division is significant
because it allows for potential extirpation of the species within the
contiguous United States through loss of small populations and lack of
demographic and genetic connectivity of the two populations. This
difference in conservation status is likely to become more significant
in light of threats discussed in the five factors analyzed below.
Therefore, we find that the difference in the conservation statuses in
Canada and the United States result in vulnerability to the significant
threats (discussed below) in the U.S. wolverine population but not for
the Canadian population. Existing regulatory mechanisms are inadequate
to ensure the continued existence of wolverines in the contiguous
United States in the face of these threats. Therefore, it is our
determination that the difference in conservation status between the
two populations is significant in light of section 4(a)(1)(D) of the
Act, because existing regulatory mechanisms appear sufficient to
maintain the robust conservation status of the Canada-Alaska
population, while existing regulatory mechanisms in the contiguous
United States are insufficient to protect the wolverine from threats
due to its depleted conservation status. As a result, the contiguous
United States population of the wolverine meets the discreteness
criterion in our DPS Policy (61 FR 4725). Consequently, we use the
international border between the United States and Canada to define the
northern boundary of the North American wolverine DPS.
Analysis for Significance
If we determine a population segment is discrete, its biological
and ecological significance will then be considered in light of
Congressional guidance that the authority to list DPS's be used
sparingly while encouraging the conservation of genetic diversity. In
carrying out this examination, we consider available scientific
evidence of the population's importance to the taxon to which it
belongs (i.e., the North American wolverine (Gulo gulo luscus). Our DPS
policy states that this consideration may include, but is not limited
to: (1) Persistence of the discrete population segment in an ecological
setting unusual or unique for the taxon; (2) evidence that loss of the
discrete population segment would result in a significant gap in the
range of the taxon; (3) evidence that the discrete population segment
represents the only surviving natural occurrence of a taxon that may be
more abundant elsewhere as an introduced population outside its
historic range; or (4) evidence that the discrete population segment
differs markedly from other populations of the species in its genetic
characteristics. Below we address Factors 1, 2, and 4. Factor 3 does
not apply to the continental U.S. wolverine population because North
American wolverines are distributed widely across Alaska and Canada.
Significant Gap in the Range of the Taxon
Loss of wolverines in the contiguous United States would represent
a significant gap in the range of the taxon. Wolverines once lived
throughout the North American Rocky Mountains from Alaska and Canada,
south through Colorado and into New Mexico, and in the North Cascades
of Washington and the Sierra Nevada Range of California--an extent
covering approximately 38[deg] of latitude. Wolverines were extirpated
[[Page 78041]]
from most of the southern portions of their historic range, including
all of the Sierra Nevada in California and all of Colorado, and
possibly even the North Cascades and northern Rocky Mountains in the
early 20th century (Aubry et al. 2007, Table 1), a loss of
approximately 15[deg] of latitude. The wolverines that have moved to
California and Colorado in the past 2 years (Moriarty et al. 2009,
Figure 1; Inman et al 2009, pp. 22-25) may represent the initial
attempts to recolonize the southernmost extent of the species' historic
range and a continuation of a recolonization of the contiguous United
States that began in the 1930s (Aubry et al. 2007, Table 1). Based on
the current scientific information, we conclude that there is at least
one wolverine each in the Sierra Nevada and southern Rocky Mountains.
Both of these animals are males that dispersed from known populations
rather than being from undiscovered remnant populations native to the
regions in question, and there is no reason to believe that functional
populations exist in these areas. Today, the contiguous United States
represents the southernmost reach of the wolverine's range. The loss of
this population would be significant because it would substantially
curtail the range of the wolverine by moving the southern range
terminus approximately 15[deg] of latitude to the north (or
approximately 40 percent of the latitudinal extent of wolverine range)
and eliminate wolverines from the fauna of the contiguous United
States. Therefore, the loss of this population would result in a
significant gap in the range of the taxon. The estimated area that
would be lost from wolverine range in North America if the contiguous
U.S. population was extirpated is 205,942 km\2\ (79,515 mi\2\) based on
the habitat model developed by Copeland et al. (2010, entire; Copeland
2010, pers. comm.).
Given the wolverine's historic occupancy of the contiguous United
States and the portion of the historic range they represent,
maintenance and recovery of wolverines in their current range would
provide some security for the rest of the taxon if conditions in Canada
and Alaska deteriorated to the point that wolverines become endangered
there. Populations on the periphery of species' ranges tend to be given
lower conservation priority because they are thought to exist in low-
quality habitats, and are also thought to be the populations that are
least likely to survive a reduction in range (Wolf et al. 1996, p.
1147). However, this tendency presumes that the ultimate cause of the
species' extinction will be one that operates by eroding away the
species' range beginning at the periphery and progressing to the
center. This presumption is based on biogeographical information that
habitat and population densities of species are highest near the center
of the species' range, and decline near the edge (Brown and Lomolino
1998, Figure 4.16). Data from real range collapses of species from
around the world illustrate that species' ranges tend to collapse to
peripheral areas rather than to the center of their historic ranges
(Lomolino and Channell 1995, p. 342; Channell and Lomomolino 2000, pp.
84-86). Of 96 species whose last remnant populations were found either
in the core or periphery of their historic range (rather than some in
both core and periphery), 91 (95 percent) of the species were found to
exist only in the periphery, and 5 (5 percent) existed solely in the
center (Channell and Lomolino 2000, p. 85). Available scientific data
support the importance of peripheral populations for conservation
(Fraser 1999, entire; Lesica and Allendorf 1995, entire).
Based upon the 15 degree latitude gap that would result in the
range of the wolverine if the U.S. population was lost, we determine
that the loss of the contiguous U.S. wolverine population would result
in a significant gap in the range of the taxon. Thus, the DPS meets the
definition of significant in our DPS policy.
Unusual or Unique Ecological Setting
Wolverines in the contiguous United States exist in an ecosystem
that requires extensive movements between habitats to maintain
demographic viability and genetic diversity. Within the range of North
American wolverines, the northern Rocky Mountains and North Cascades
have the highest diversity of large predators and native ungulate prey
species, which results in complex ecological interaction among ungulate
prey, predators, scavenger groups, and vegetation (Smith et al. 2003,
pp. 330-339). In the proposed DPS area, wolverines share habitats with
gray wolves (Canis lupus), black bears (Ursus americanus), grizzly
bears (Ursus arctos horribilis), puma (Felis concolor), lynx (Lynx
canadensis), coyotes (Canis latrans), badgers (Taxidea taxus), bobcats
(Felis rufus), fishers (Martes pennanti), and martens (Martes
americana). The unique and diverse assemblage of native prey, and
sources of carrion, for these carnivores include elk (Cervus elaphus),
mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus
virginianus), moose (Alces alces), woodland caribou (Rangifer caribou),
bighorn sheep (Ovis canadensis), mountain goats (Oreamnos americanus),
pronghorn (Antilocapra americana), bison (Bison bison) (only in the
Greater Yellowstone Area), and beaver (Castor canadensis).
Despite the fragmented nature of the habitat and the high diversity
of prey, wolverines in the contiguous United States appear to use
habitat attributes that are similar to wolverine populations range-wide
(Copeland et al. 2010, entire), and do not appear to exist in an
unusual or unique ecological setting. Thus, we did not rely on this
factor when determining that the wolverine in the United States is
significant to the taxon as a whole.
Marked Genetic Differences
Several genetics studies have confirmed genetic differentiation
between wolverines in the contiguous United States and those in Canada
and Alaska (Cegelski et al. 2006, pp. 203-205; Kyle and Strobeck 2002,
p. 342; Schwartz et al. 2007, p. 2175). The U.S. Rocky Mountain
populations group together in mitochondrial DNA (mtDNA) analyses
(Schwartz et al. 2007, p. 2176). The primary genetic difference is a
reduction of diversity in the United States as compared with Canada so
that the contiguous U.S. populations contain a subset of the genetics
of the Canada-Alaska population (Cegelski et al. 2006, p. 200; Schwartz
et al. 2007, p. 2172). The contiguous U.S. populations contain 3 mtDNA
haplotypes and Canada-Alaska samples also contain those three
haplotypes plus ten more. Idaho has substantially lower heterozygosity
(a measure of the genetic variation in a population) (42 percent) than
the nearest Canadian population (61 percent) sampled only 700 km (435
mi) away (Kyle and Strobeck, 2001, p. 341, 345). Genetic structure in
the contiguous United States indicates that population fragmentation
caused by either natural or anthropogenic factors, has reduced gene
flow between populations, and that genetic drift has occurred and may
still be occurring (Kyle and Strobeck 2001, p. 343; Cegelski et al.
2003, pp. 2914-2915; Cegelski et al. 2006, p. 208). This reduced
genetic diversity and gene flow coincides with the international border
and indicates that individuals are not passing freely between Canadian
and U.S. populations (Schwartz et al. 2009, pp. 3229-3230). Four
wolverine subpopulations have been identified within Montana based on
genetic data (Cegelski et al. 2003, p. 2913; Guillot et al. 2005, p.
1274). Subsequent work suggests that Montana may contain a
[[Page 78042]]
single population that is genetically structured by both distance and
ecological factors meaning that wolverines across their range in
Montana occasionally exchange individuals but do not freely interbreed
because of the great distances and frequent unsuitable habitat that
separates populations (Schwartz et al. 2009, p. 3227).
The levels of gene flow in the contiguous United States are low
compared to wolverines in Alaska and Northern Canada (Kyle and Strobeck
2001; 2002, pp. 343-345), indicating that habitat in the contiguous
United States is much more fragmented than habitats further north in
Canada and Alaska (Schwartz et al. 2009, p. 3227). A distinct break was
identified between the U.S. population and the Canadian populations
(Cegelski et al. 2006, p. 203; Schwartz et al. 2009, pp. 3229-3230).
Similarly, Schwartz et al. (2007, p. 2176) found that wolverines in
Idaho, Montana, and Wyoming have few haplotypes (2 in the main Rocky
Mountain group, plus 1 identified by Cegelski et al. 2006 in north-
central Montana) compared to 13 distinct haplotypes in Canada, despite
greater numbers of samples collected in the contiguous United States.
Of these two haplotypes found by Schwartz, one is predominant, with 71
of 73 samples containing this haplotype (Schwartz et al. 2007, p.
2176).
The genetic differences between the U.S. and Canadian wolverine
populations identified above are the result of loss of genetic
diversity, either through genetic drift or founder effects. The
differences consist of lower genetic diversity in the United States, a
difference that is of conservation concern because it reflects loss of
genetic diversity through inbreeding. This is not the kind of genetic
difference that would lead us to conclude that a population is
significant under our DPS policy. That policy is designed to ensure the
protection of rare or unique biological diversity rather than mere
differences in gene frequencies. Therefore, we do not rely on marked
genetic differences in our determination of significance for this DPS.
Summary for Significance
We conclude that the wolverine population in the contiguous United
States is significant because its loss would result in a significant
gap in the range of the taxon.
Summary of the Distinct Population Segment Analysis
We conclude that the wolverine population in the contiguous United
States is both discrete and significant under our DPS policy.
Conservation status of wolverines in the contiguous United States is
less secure than wolverines in adjacent Canada due to fragmented
habitat, small population size, reduced genetic diversity, and their
vulnerability to threats analyzed in this finding. Loss of the
contiguous U.S. wolverines would result in a significant gap in the
range of the taxon. Therefore, we determine that the wolverine in the
48 States, as currently described, meets both the discreteness and
significance criteria of our DPS policy, and is a listable entity under
the Act. We now consider the conservation status of this DPS.
Summary of Information Pertaining to the Five Factors
Section 4 of the Act (16 U.S.C. 1533) and implementing regulations
(50 CFR part 424) set forth procedures for adding species to the
Federal Lists of Endangered and Threatened Wildlife and Plants. Under
section 4(a)(1) of the Act, a species may be determined to be
endangered or threatened based on any of the following five factors:
(A) The present or threatened destruction, modification, or curtailment
of its habitat or range; (B) overutilization for commercial,
recreational, scientific, or educational purposes; (C) disease or
predation; (D) the inadequacy of existing regulatory mechanisms; or (E)
other natural or manmade factors affecting its continued existence. In
making this finding, information pertaining to the U.S. DPS of the
wolverine in relation to the five factors provided in section 4(a)(1)
of the Act is discussed below.
We are required by the Act to assess threats information that may
occur within the foreseeable future. We define foreseeable future as a
timeframe in which impacts can be reasonably expected to occur. As
discussed below, we have identified one primary threat to the wolverine
DPS: climate change. Other threats are secondary and only rise to the
level of threats to the DPS as they may work in concert with climate
changes to affect the conservation status of the species. For this
reason we use a foreseeable future identified for climate change (out
to 2099) for all of the threat factors. For most threat factors, future
projections are not available and it is assumed that current trends
will continue unless information exists to the contrary.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
Under Factor A we will discuss a variety of impacts to wolverine
habitat including: (1) Climate change, (2) human use and disturbance,
(3) dispersed recreational activities, (4) infrastructure development,
(5) transportation corridors, and (6) land management. Many of these
impact categories overlap or act in concert with each other to affect
wolverine habitat. Climate change is discussed under Factor A because
although climate change may affect wolverines directly by creating
physiological stress, the primary impact of climate change on
wolverines is expected to be through changes to the availability and
distribution of wolverine habitat.
Two efforts to map wolverine habitat in the contiguous United
States have been completed, although only one has been peer-reviewed
(Brock et al. 2007, entire; Copeland et al. 2010, entire). As the
single peer reviewed source, we rely on Copeland et al. (2010, entire)
and supplemental information about that publication supplied in
Copeland (pers. comm. 2010, p. 1) unless specified otherwise. We also
report some statistics from the Brock et al. (2007) analysis because
the authors report habitat broken down by land ownership whereas
Copeland et al. (2010) do not. Both the Copeland et al. (2010) and
Brock et al. (2007) analyses largely agree on the location of wolverine
habitat within their geographic area of overlap; however, Brock et al.
(2007) tends to be more inclusive and hence habitat area estimates for
their model tend to be somewhat larger than for Copeland et al. (2010).
Within the three States that currently harbor wolverines in the
northern Rocky Mountains (Montana, Idaho, and Wyoming), an estimated
104,363 km\2\ (40,295 mi\2\) of wolverine habitat exists (Copeland
2010, pers. comm.). Based on the habitat model developed by Brock et
al. (2007), 95 percent (120,000 km\2\; 46,332 mi\2\) is in Federal
ownership with the largest portion of that (108,969 km\2\; 42,073
mi\2\) managed by the U.S. Forest Service (Forest Service) (Inman
2007b, pers. comm.).
Reduction in Habitat Due to Climate Change
Department of the Interior Secretarial Order Number 3289, issued
September 14, 2009 (Department of the Interior (DOI) 2009), provides
guidance that DOI bureaus and offices shall ``* * * [c]onsider and
analyze potential climate change impacts when undertaking long-
[[Page 78043]]
range planning exercises, setting priorities for scientific research
and investigations, developing multi-year management plans, and making
major decisions regarding potential use of resources under the
Department's purview.''
The Intergovernmental Panel on Climate Change (IPCC) was
established in 1988 by the World Meteorological Organization and the
United Nations Environment Program in response to growing concerns
about climate change and, in particular, the effects of global warming.
Although the extent of warming likely to occur is not known with
certainty at this time, the IPCC has concluded that warming of the
climate is unequivocal, and that continued greenhouse gas emissions at
or above current rates will cause further warming (IPCC 2007, p. 30).
Climate-change scenarios estimate that the mean air temperature could
increase by more than 3 degrees Celsius (5.4 degrees Fahrenheit) by
2100 (IPCC 2007, p. 46). The IPCC also projects that there will very
likely be regional increases in the frequency of hot extremes, heat
waves, and heavy precipitation (IPCC 2007, p. 46), as well as increases
in atmospheric carbon dioxide (IPCC 2007, p. 36).
We recognize that there are scientific uncertainties on many
aspects of climate change, including the role of natural variability in
climate. In our analysis, we rely both on synthesis documents (e.g.,
IPCC 2007; Karl et al. 2009) that present the consensus view of a very
large number of experts on climate change from around the world, and on
three analyses that relate the effects of climate changes directly to
wolverines (Gonzalez et al. 2008, entire; Brodie and Post 2009, entire;
McKelvey et al. 2010b, entire). McKelvey et al. (2010b) is the most
sophisticated analysis so far available of climate change effects to
wolverines. This report is based on data from global climate models
including both temperature and precipitation downscaled to reflect the
regional climate patterns and topography found within the range of
wolverines in the contiguous United States. For this reason we believe
the McKelvey et al. (2010) report represents the best scientific
information available regarding the impacts of climate change to
wolverine habitat for this 12-month finding.
Brodie and Post (2009) uses correlation to infer historical impacts
of climate changes on Canadian wolverine populations based on harvest
returns, but does not provide predictions of the future effects of
climate changes on wolverines or wolverine habitat. Their report is
suggestive of likely negative impacts to wolverine populations from
continued warming; however, they do not provide estimates of the scale
or spatial extent of future impacts. The Brodie and Post (2009) paper
has also received several published criticisms of its methods (McKelvey
et al. 2010a, entire; Devink et al. 2010, entire). The authors
responded to these criticisms, although the controversy remains (Brodie
and Post 2010b, entire). The report by Gonzalez et al. (2008) was the
first available wolverine climate change analysis; however, the methods
used in the report took into account only changes in temperature and
not precipitation.
Snowpack changes (and concomitant changes to wolverine habitat
suitability) result from both changes in temperature (negative
relationship) and changes in snowfall (positive relationship). Because
many climate models predict higher precipitation levels associated with
climate warming, the interaction between these two variables can be
quite complex. Consequently, predictions about snow coverage that rely
only on temperature projections are less reliable than those that rely
on both temperature and precipitation. McKelvey et al. (2010b, entire)
report projections for wolverine habitat and dispersal routes through
the time interval from 2070 to 2099. Therefore, we use 2099 as the
outer limit of the foreseeable future for climate change in this
finding.
Climate Effects to Wolverines
Across their worldwide distribution, wolverines are dependent on
persistent spring snow cover for successful reproduction (Pulliainen
1968, pp. 338-341; Myrberget 1968, p. 115; Copeland 1996, pp. 93-94;
Magoun and Copeland 1998, pp. 1315-1319; Aubry et al. 2007, p. 2153;
Inman et al. 2007c, pp. 71-72; Copeland et al. 2010, entire). No
records exist of wolverines denning anywhere but in snow, despite the
wide availability of snow-free denning opportunities within the
species' geographic range. The snow tunnel and complex structure
associated with dens is likely required to protect young from
interspecific and intraspecific predation (Persson et al. 2003, pp. 25-
26; Magoun and Copeland 1998, p. 1318). A layer of deep snow may also
add crucial insulation from cold temperatures and wind prevalent in
denning habitat (Pulliainen 1968, p. 342; Bjarvall et al. 1978, p. 24-
25; Copeland 1996, p. 100; Magoun and Copeland 1998, p. 1318).
Female wolverines have been observed to abandon reproductive dens
when temperatures warm and snow conditions become wet (Magoun and
Copeland 1998, p. 1316), indicating that the condition of the snow is
also important to successful reproduction, and that the onset of spring
snowmelt forces female wolverines to move kits into alternate denning
sites with better snow conditions, if they are available. Female
wolverines establish reproductive dens at elevations higher than those
used by non-reproductive wolverines (Copeland 1996, p. 94; Magoun and
Copeland 1998, pp. 1315-1316; Inman et al. 2007c, p. 71), suggesting
that females find the conditions necessary for successful denning in
the upper portion of their home range where snow is most persistent and
occurs in the heaviest accumulations.
In the contiguous United States, wolverine year-round habitat is
found at high elevations in conifer forests near treeline and in rocky
alpine habitats such as cirque basins and avalanche chutes that have
food sources such as marmots, voles, and carrion (Hornocker and Hash
1981, p. 1296; Copeland 1996, p. 124; Magoun and Copeland 1998, p.
1318; Copeland et al. 2007, p. 2211; Inman et al. 2007a, p. 11). In
fact, the areas defined by persistent spring snow cover that wolverines
use for denning also correspond closely to wolverine habitat use in the
nonreproductive season; essentially, wolverines use the coldest
available landscapes within their geographic range in the contiguous
United States (Copeland et al. 2010, Figure 6), likely due to a
physiological need for cooler temperatures during the warm season.
Mean seasonal elevations used by wolverines in the northern Rocky
Mountains and North Cascades vary between 1,400 and 2,600 m (4,592 and
8,528 ft) depending on location, but are always relatively high on
mountain slopes (Hornocker and Hash 1981, p. 1291; Copeland et al.
2007, p. 2207, Aubry et al. 2007, p. 2153). Elevation ranges used by
historical wolverine populations in the Sierra Nevada and southern
Rocky Mountains are unknown, but presumably wolverines used higher
elevations, on average, than more northerly populations to compensate
for the higher temperatures found at lower latitudes. In the contiguous
United States, valley bottom habitat appears to be used only for
dispersal movements and not for foraging or reproduction (Inman et al.
2009, pp. 22-28). Wolverine reproductive dens have been located in
alpine, subalpine, taiga, or tundra habitat (Myrberget 1968, p. 115;
Pulliainen 1968, pp. 338-341; Bj[auml]rvall 1982, p. 318; Lee and
Niptanatiak 1996, p. 349; Landa et al. 1998, pp. 451-452;
[[Page 78044]]
Magoun and Copeland 1998, pp. 1317-1318). Wolverines rarely, or never,
den in lower elevation forested habitats, although they may occupy
these habitats seasonally (Magoun and Copeland 1998, p. 1317).
Due to dependence of wolverines on deep snow that persists into
late spring both for successful reproduction and for year-round
habitat, and their restricted distribution in areas that maintain
significant snow late into the spring season, we conclude that deep
snow maintained through the denning period is an essential feature of
wolverine habitat. Reduction of this habitat feature would reduce
wolverine habitat proportionally.
Based on the information described above, we analyzed the effects
of climate change on wolverines through three primary mechanisms: (1)
Reduced snowpack and earlier spring runoff, which would reduce suitable
habitat for wolverine denning; (2) increase in summer temperatures
beyond the physiological tolerance of wolverines; and (3) ecosystem
changes due to increased temperatures, which would move lower elevation
ecosystems to higher elevations, eliminating high-elevation ecosystems
on which wolverines depend and increasing competitive interactions with
species that currently inhabit lower elevations. These mechanisms would
tend to push the narrow elevational band that wolverines use up in
elevation and, due to the conical structure of mountains, upward shifts
would result in reduced overall suitable habitat for wolverines.
Reduced Snow Pack
Warmer winter temperatures are reducing snow pack in western North
American mountains through a higher proportion of precipitation falling
as rain and higher rates of snowmelt during winter (Hamlet and
Lettenmaier 1999, p. 1609; Brown 2000, p. 2347; Mote 2003, p. 3-1;
Christensen et al. 2004, p. 347; Knowles et al. 2006, pp. 4548-4549).
This trend is expected to continue with future warming (Hamlet and
Lettenmaier 1999, p. 1611; Christensen et al. 2004, p. 347; Mote et al.
2005, p. 48). Shifts in the initiation of spring runoff toward earlier
dates are also well documented (Hamlet and Lettenmaier 1999, p. 1609;
Brown 2000, p. 2347; Cayan et al. 2001, pp. 409-410; Christensen et al.
2004, p. 347; Mote et al. 2005, p. 41; Knowles et al. 2006, p. 4554).
Earlier spring runoff leads to lack of snow or degraded snow conditions
during April and May, the critical time period for wolverine
reproductive denning. In addition, a feedback effect hastens the loss
of snow cover due to the reflective nature of snow and the relative
heat-absorbing properties of non-snow-covered ground. This effect leads
to the highest magnitude of warming occurring at the interface of snow-
covered and exposed areas, increasing the rate at which melting occurs
in spring (Groisman et al. 1994a, pp. 1637-1648; Groisman et al. 1994b,
pp. 198-200). Due to the importance of deep snow cover in spring for
wolverine reproduction, currently suitable habitat that lost this
feature would be rendered unsuitable for wolverines.
Ecosystem Changes Associated With Climate Change
Changes in temperature and rainfall patterns are expected to shift
the distribution of ecosystems northward (IPCC 2007c, p. 230) and up
mountain slopes (McDonald and Brown 1992, pp. 411-412; Danby and Hik
2007, pp. 358-359, IPCC 2007c, p. 232). As climate changes over a
landscape, the ecosystems that support wolverines are likely to move,
tracking the change of temperature, but with a time lag depending on
the ability of individual plant species to migrate (McDonald and Brown
1992, pp. 413-414; Hall and Fagre 2003, p. 138; Peterson 2003, p. 652).
Wolverines in the contiguous United States, due to their reliance on
mountainous habitat, will most likely adjust to climate changes by
using higher elevations on mountain slopes, not by shifting their
latitudinal distribution. Along a latitudinal gradient through the
historic distribution of wolverines, records tended to be found at
higher elevations in southern latitudes (Aubry et al. 2007, p. 2153),
which suggests that wolverines were compensating for increased
temperature at low latitudes by selecting higher elevations. Therefore,
the regional availability of suitable habitat is not likely to change
significantly (i.e., at least some wolverine habitat will continue to
be available in all regions where wolverines currently occur), but
within regional landscapes, smaller areas will be suitable for
wolverines. Mountain ranges with maximum elevations within the
elevation band that wolverines currently use, such as much of the
wolverine habitat in central Idaho, may become entirely unsuitable for
wolverines with the projected level of warming reported in McKelvey et
al. (2010b, Figure 3).
Timing of Climate Effects
Unlike snow conditions, which respond directly to temperature
change without a time lag, ecosystem responses to temperature change
lag depending on constituent species' individual migratory abilities.
Wolverines are described as a ``treeline'' species because they are
most often found in an elevation band that is approximately centered on
the alpine treeline at any given locality within their range. Alpine
treelines are maintained by a complex set of climactic and biotic
factors, of which temperature is significantly important (Cogbill and
White 1991, p. 169; H[auml]ttenschwiler and K[ouml]rner 1995, p. 367;
Jobb[aacute]gy and Jackson 2000, p. 259; Pellat et al. 2000, pp. 80-
81). However, the conditions that favor tree establishment and lead to
elevational advance in the treeline may exist only sporadically,
increasing time lags associated with treeline response to warming
(Hessl and Baker 1997, p. 181; Klasner and Fagre 2002, p. 54). Within
wolverine habitats, treelines have advanced up mountain slopes since
1850, due to climate warming, and this trend is expected to continue
into the future (Hessl and Baker 1997, p. 176; Hall and Fagre 2003, p.
138). We expect that species reliant on resources associated with this
biome will need to shift accordingly. Given the irregular nature of
treeline response to warming, treeline migration is likely to lag
significantly behind the climate warming that causes it.
Magnitude of Climate Effects on Wolverine
Several studies relating the effects of climate changes on
wolverines in the past, present, and future are now available (Brock
and Inman 2007, entire; Gonzales et al. 2008, pp. 1-5; Brodie and Post
2010, entire; McKelvey et al. 2010b, entire). The Gonzalez et al.
report and the report by Brock and Inman (2007) were both preliminary
attempts to analyze climate change impacts to wolverines, but are not
currently considered the best available science because they did not
consider the effects of both changes in temperature and precipitation
that may affect the distribution of persistent spring snow cover
(McKelvey 2010, entire). Both Brock and Inman (2007) and Gonzalez et
al. (2008) have been superseded by a more sophisticated analysis
provided by McKelvey et al. (2010b). This analysis includes climate
projections at a local scale for wolverine habitats and analyzes the
effects of both temperature changes and changes to precipitation
patterns. Lack of accounting for changes in precipitation was a
weakness cited by the authors of both Brock and Inman (2007) and
Gonzalez et al. (2008).
Brodie and Post (2010, entire) correlate the decline in wolverine
populations in Canada over the past
[[Page 78045]]
century with declining snowpack due to climate change over the same
period. However, correlation does not infer causation; other factors
could have caused the decline. The analysis used harvest data to infer
population trends as well as its reliance on correlation to infer
causation (McKelvey et al. 2010a, entire); in this case, historic
climate changes are inferred to have caused the declines in harvest
returns, which are thought by the authors to reflect actual population
declines. Due to the above-stated concerns, we view the analysis of
Brodie and Post (2010, entire) with caution, although we do agree that
the posited mechanism, of loss of snowpack affecting wolverine
populations and distribution, likely has merit.
McKelvey et al. (2010, entire) used downscaled global climate
models to project the impacts of changes in temperature and
precipitation to wolverine habitat as modeled by Copeland et al. (2010,
entire). The authors also present an alternative method for evaluating
climate impacts on wolverine habitat, by merely projecting onset of
spring snowmelt to occur 2 weeks earlier than it currently does,
essentially asking the question: What would happen if spring snowmelt
occurred 2 weeks earlier than it occurs now? Based on this information,
wolverine habitat in the contiguous United States, which supports
approximately 250 to 300 wolverines, is shrinking and is likely to
continue to shrink with increased climate warming (McKelvey et al.
2010b, Figures 1, 3). Habitat losses are likely to occur throughout the
range of the DPS and are projected to be most severe in central Idaho
(McKelvey et al. 2010b, Figures 1, 3). However, large areas of snow
cover are likely to remain in British Columbia, North Cascades, Greater
Yellowstone Area (GYA), and the Glacier Park-Bob Marshall Wilderness of
Montana (McKelvey et al. 2010b, p. 14, Figure 2). The southern Rocky
Mountains of Colorado retained significant high-elevation snow in some
models but not others, and so may be another area that could support
wolverine populations in the face of climate changes (McKelvey et al.
2010b, p. 19). The mountainous areas of Idaho that currently support
wolverines are likely to lose proportionally more snow-covered area
than other areas within the contiguous United States, making this area
of wolverine habitat relatively more sensitive to climate warming
(McKelvey et al. 2010b, p. 14).
Overall, wolverine habitat in the contiguous United States is
expected to get smaller and more highly fragmented as individual
habitat islands become smaller and the intervening areas between
wolverine habitat become larger (McKelvey et al. 2010b, Figures 1, 3).
Composite projections for the time interval centered on 2045 predict
that 23 percent of current wolverine habitat in the contiguous United
States will be lost due to climate warming (McKelvey et al. 2010b, p.
14). That loss expands to 63 percent of wolverine habitat by the time
interval between 2070 and 2099. Given the spatial needs of animals with
the home range size of wolverines and the limited availability of
suitable wolverine habitat in the contiguous United States, this
projected gross loss of habitat area should result in a loss of
wolverine numbers that is greater than the overall loss of habitat
area. As habitat patches become smaller and more isolated, they are
likely to lose the ability to support wolverines as some home ranges
become so reduced that they cannot support individual animals, and
others become so fragmented or isolated that they no longer continue to
function.
In addition to the effects of gross habitat loss, we expect
wolverine populations to be negatively affected by changes in the
spatial distribution of habitat patches as remaining habitat islands
become progressively more isolated from each other as a result of
climate changes (McKelvey et al. 2010b, Figure 8). Currently, wolverine
habitat in the contiguous United States can be described as a series of
habitat islands. Some of these islands are large and clumped closely
together, such as in the North Cascades, Glacier Park-Bob Marshall
Wilderness complex in Montana, and the GYA. Other islands are smaller
and more isolated such as the island mountain ranges of central and
southwestern Montana. Inbreeding and consequent loss of genetic
diversity has occurred in the past within these smaller islands of
habitat (Cegelski et al. 2006, p. 208), and genetic exchange between
subpopulations is most difficult to achieve (Schwartz et al. 2009,
Figure 4). Climate change projections indicate that, as warming
continues, large contiguous blocks will become reduced in size and
isolated to the extent that their ability to support robust populations
is reduced and their connectivity to other source populations resembles
the current situation for our most isolated wolverine populations
(McKelvey et al. 2010b, Figure 8). This habitat alteration would result
in a high likelihood of loss of genetic diversity due to inbreeding
within a few generations (Cegelski et al. 2006, p. 209). Further
isolation of wolverines on small habitat islands with reduced
connectivity to other populations would also increase the likelihood of
subpopulations loss due to demographic stochasticity, impairing the
functionality of the wolverine metapopulation in the contiguous United
States.
We believe that McKelvey et al. (2010b, entire) represents the best
available science for predicting the future impacts of climate change
on wolverine habitat for four primary reasons. First, their habitat
projections are based on Global Climate Models which are thought to be
the most reliable predictors of future climate available (IPCC 2007a,
p. 12). Second, they conducted downscaling analyses to infer geographic
climate variation at a scale relevant to wolverine habitat. Third, they
used a hydrologic model to predict snow coverage during the spring
denning period (the strongest correlate with wolverine reproductive
success). Fourth, they used the habitat model developed by Copeland et
al. (2010, entire), to relate projected climate changes to wolverine
habitat. This report has not been peer-reviewed or published at the
time of this finding; however, based on our analysis of the methods and
analysis used by the authors, we conclude it constitutes the best
available information on the likely impact of climate change on
wolverine distribution in the contiguous United States. Based on the
analysis presented, we conclude that climate changes are likely to
result in permanent loss of a significant portion of essential
wolverine habitat within the foreseeable future. Additional impacts of
climate change will be increased habitat fragmentation as habitat
islands become smaller and intervening habitat disappears. Eventually,
these processes are likely to lead to a breakdown of metapopulation
dynamics as subpopulations are no longer able to rescue each other
after local extinctions due to a lack of connectivity. It is also
likely that loss of genetic diversity leading to lower fitness will
occur as population isolation increases.
Summary of Impacts of Climate Changes
Wolverine habitat is projected to decrease in area and become more
fragmented within the foreseeable future as a result of climate
changes. These impacts are expected to have direct and indirect effects
to wolverine populations in the contiguous United States including
reducing the number of wolverines that can be supported by available
habitat and reducing the ability of wolverines to travel between
patches of suitable habitat. This
[[Page 78046]]
reduction in connectivity is likely to affect metapopulation dynamics
making it more difficult for subpopulations to recolonize areas where
wolverines have been extirpated and to bolster the genetics or
demographics of adjacent subpopulations. Due to the extent and
magnitude of climate change impacts to wolverines and their habitat, we
conclude that climate change constitutes a threat to the contiguous
U.S. DPS of wolverines in the foreseeable future.
Habitat Impacts Due to Human Use and Disturbance
Because wolverine habitat is generally inhospitable to human use
and occupation and most of it is also Federally managed, wolverines are
somewhat insulated from impacts of human disturbances from industry,
agriculture, infrastructure development, or recreation. Human
disturbance in the contiguous United States has likely resulted in the
loss of some wolverine habitat, although this loss has not yet been
quantified. Sources of human disturbance to wolverines include winter
and summer recreation, housing and industrial development, road
corridors, and extractive industry such as logging or mining. In the
contiguous United States, these human activities and developments often
occur within or immediately adjacent to wolverine home ranges, such as
in alpine or boreal forest environments at high elevations on mountain
slopes. They can also occur in a broader range of habitats that are
occasionally used by wolverines during dispersal or exploratory
movements--habitats that are not suitable for the establishment of home
ranges and reproduction.
Little is known about the behavioral responses of individual
wolverines to human presence, or about the species' ability to tolerate
and adapt to repeated disturbance. Some postulate that disturbance may
reduce the wolverine's ability to complete essential life-history
activities, such as foraging, breeding, maternal care, routine travel,
and dispersal. It may decrease habitat value, cause animals to avoid
disturbed areas, or act as a barrier to movement (Packila et al. 2007,
pp. 105-110). How effects of disturbance extend from individuals to
characteristics of populations, such as vital rates (e.g.,
reproduction, survival, emigration, and immigration) and gene flow, and
ultimately to wolverine population or meta-population persistence, is
unknown.
Wolverine habitat is generally characterized by the absence of
human presence and development (Hornocker and Hash 1981, p. 1299; Banci
1994, p. 114; Landa et al. 1998, p. 448; Rowland et al. 2003, p. 101;
Copeland 1996, pp. 124-127; Krebs et al. 2007, pp. 2187-2190). This
negative association is sometimes interpreted as active avoidance of
human activity, but it may simply reflect the wolverine's preference
for cold, snowy, and high-elevation habitat. In the contiguous United
States, wolverine habitat is typically associated with high-elevation
(e.g., 2,100 m to 2,600 m (6,888 ft to 8,528 ft)) subalpine forests
that comprise the Hudsonian Life Zone (weather similar to that found in
northern Canada), environments not typically used by people for
housing, industry, agriculture, or transportation. However, occupied
wolverine habitat supports a variety of activities associated with
extractive industry, such as logging and mining, as well as
recreational activities in both summer and winter.
At broad spatial scales, it is difficult to separate human
disturbance from negative, although interdependent, effects of habitat
loss and fragmentation, and historic overexploitation; factors that
could contribute to current differences in distributions of wolverines
and humans.
Maternal females and their young often vacate dens if they feel
threatened (Myrberget 1968, p. 115), which is a common predator
avoidance strategy among carnivores. The security of the den and the
surrounding foraging areas (i.e., protection from disturbance by humans
and predation by other carnivores) is an important aspect of den site
selection. Abandonment of natal and maternal dens may also be a
preemptive strategy that females use in the absence of disturbance by
humans or predators. Preemptive den abandonment might confer an
advantage to females if prolonged use of the same den makes that den
more evident to predators.
The reasons for den abandonment are uncertain. Managing human
activity in wolverine habitat to limit premature den abandonment and
associated stress and energy expenditure of maternal females may be
important for successful reproduction. Premature den abandonment may
also increase incidental mortality of offspring. Ultimately, low
reproductive success and high mortality may reduce population viability
in areas with high incidence of disturbance (Banci 1994, pp. 110-111).
The potentially negative effects of disturbance may be more important
at the southern margin of the species' North American range where
wolverine productivity is particularly low (Inman et al. 2007c, p. 70).
Wolverines typically occupy severe, unproductive environments that
support low numbers of adult females with characteristically low birth
rates (Persson et al. 2006, p. 77; Inman et al. 2007a, p. 68). The
life-history strategy of wolverines makes it unlikely that they could
compensate for increased mortality due to disturbance (Krebs et al.
2007, p. 2190; Persson et al. 2006, pp. 77-78), and they may be more
vulnerable to extirpation than species with high reproductive rates
(Ruggiero et al. 2007, p. 2146).
For the purposes of this finding, we divide human disturbance into
four categories: (1) Dispersed recreational activities with primary
impacts to wolverines through direct disturbance (e.g., snowmobiling
and heli-skiing); (2) disturbance associated with permanent
infrastructure such as residential and commercial developments, mines,
and campgrounds; (3) disturbance and mortality associated with
transportation corridors; and (4) disturbance associated with land
management activities such as forestry, or fire/fuels reduction
activities. Overlap between these categories is extensive, and it is
often difficult to distinguish effects of infrastructure from the
dispersed activities associated with that infrastructure. However, we
believe that these categories account for most of the potential effects
related to disturbance of wolverines.
Dispersed Recreational Activities
Dispersed recreational activities occurring in wolverine habitat
include snowmobiling, heli-skiing, hiking, biking, off- and on-road
motorized use, hunting, fishing, and other uses. Among the most often
cited as potential threats to wolverines are snowmobiling and heli-
skiing; however, other dispersed recreation activities may have similar
effects.
One study documented (in two reports) the extent that winter
recreational activity spatially and temporally overlapped wolverine
denning habitat in the contiguous United States (Heinemeyer and
Copeland 1999, pp. 1-17; Heinemeyer et al. 2001, pp. 1-35). This study
took place in the GYA in an area of high dispersed recreational use.
The overlap of modeled wolverine denning habitat and dispersed
recreational activities was extensive. Strong temporal overlap existed
between snowmobile activity (February-April) and the wolverine denning
period (February-May). During 2000, six of nine survey units, ranging
from 3,500 to 13,600 hectares (ha) (8,645 to 33,592 acres (ac)) in
size, showed evidence of recent snowmobile use.
[[Page 78047]]
Among the six survey units with activity, the highest use covered 20
percent of the predicted denning habitat, and use ranged from 3 to 7
percent over the other survey units. Snowmobile activity was typically
intensive where detected.
Three of nine survey units in this study showed evidence of skier
activity (Heinemeyer and Copeland 1999, p. 10; Heinemeyer et al. 2001,
p. 16). Among the three units with activity, skier use covered 3 to 19
percent of the survey unit. Skiers also intensively used the sites they
visited. Combined skier and snowmobile use covered as much as 27
percent of potential denning habitat in one unit, where no evidence of
wolverine presence was detected. Although we do not have any
information on the overlap of wolverine and winter recreation in the
remaining part of the U.S. range, these areas likely do not get the
high levels of recreational use seen in the portion of the GYA examined
in this study.
Although we can demonstrate that recreational use of wolverine
habitat is heavy in some areas, we do not have any information on the
effects of these activities on the species. No rigorous assessments of
anthropogenic disturbance on wolverine den fidelity, food provisioning,
or offspring survival have been conducted. Disturbance from foot and
snowmobile traffic associated with historic wolverine control
activities (Pulliainen 1968, p. 343), and field research activities,
may cause maternal females to abandon natal dens and relocate kits to
maternal dens (Myrberget 1968, p. 115; Magoun and Copeland 1998, p.
1316; Inman et al. 2007c, p. 71).
At both a site-specific and landscape scale, wolverine natal dens
were located particularly distant from public (greater than 7.5 km (4.6
mi)) and private (greater than 3 km (1.9 mi)) roads (May 2007, p. 14-
31). Placement of dens away from public roads (and away from associated
human-caused mortality) was also a positive influence on successful
reproduction. It is not known if the detected effect is due to the
influence of the roads themselves or if there are other habitat
variables that cause the effect that are also correlated with a lack of
roads.
Disturbance at maternal dens may be more likely to cause
displacement than disturbance at natal dens (Magoun and Copeland 1998,
p. 1316), and maternal dens may be less secure from predators than
natal dens (Myrberget 1968, p. 115), presumably because maternal dens
are shallower and smaller. After pursuit by Scandinavian hunters,
females near parturition used birthing sites that were less secure than
natal dens (Pulliainen 1968, p. 343). Maternal females apparently carry
or pull their offspring to new den sites, and may be constrained by the
distance and difficulty of simultaneously moving several reluctant
offspring (Myrberget 1968, p. 115).
Stress from human activities has not been shown to affect
reproductive rates, or to render home range or larger areas of habitat
unsuitable. However, the absence of human disturbance that is afforded
by refugia may be important for wolverine reproduction (Banci 1994, p.
122; Copeland 1996, p. 126). The extent that dispersed winter
recreational activities affect selection of natal den sites by female
wolverines is little studied. Rugged terrain and dense forests may
naturally separate natal dens and wolverine foraging areas from centers
of snowmobile or backcounty skier activity. Maternal females may
specifically choose to locate dens far from winter recreation (Inman et
al. 2007c, p. 72; Heinemeyer and Copeland 1999, p. 2-9). Six of seven
natal dens documented in the Yellowstone Ecosystem occurred where
snowmobiles were not permitted, such as in designated wilderness or
national parks (Inman et al. 2007c); recreational snowmobile use
outside of these areas was common. Wolverine den, foraging, and
traveling areas have anecdotally been found to be spatially separated
from snowmobile activity (Heinemeyer et al. 2001, p. 17).
Dispersed recreation is likely to affect wolverines, at least in
local areas where this activity occurs at high intensity in wolverine
habitat. The magnitude of this effect in relation to the wolverine DPS
is difficult to determine due to a lack of information on the effects
of disturbance on wolverine vital rates, behavior, and habitat use, as
well as a general lack of reliable information about the geographic
distribution and intensity of dispersed recreational use of wolverine
habitats. For these reasons, we conclude that dispersed recreation, by
itself, is not a threat to wolverines in the contiguous United States,
but that this potential threat may act in concert with other threats to
contribute to wolverine declines. As climate changes continue to reduce
wolverine habitats, dispersed recreational uses such as snowmobiling
and skiing are likely to become more concentrated in any remaining
snow-covered areas. This is an area of concern that deserves more
scientific investigation as wolverine conservation efforts proceed into
the future.
Infrastructure
Infrastructure includes all residential, industrial, and
governmental developments such as buildings, houses, oil and gas wells,
and ski areas. Infrastructure development on private lands in the Rocky
Mountain West has been rapidly increasing in recent years and is
expected to continue as people move to this area for its natural
amenities (Hansen et al. 2002, p. 151). Infrastructure development may
affect wolverines directly by eliminating habitats, or indirectly, by
displacing wolverines from suitable habitats near developments. The
latter effect tends to be most detrimental to sensitive wildlife,
because the area of displacement may be much larger than the area of
direct habitat loss.
Wolverine home ranges generally do not occur near human
settlements, and this separation is likely due both to differential
habitat selection by wolverines and humans and to some extent,
disturbance-related effects (May et al. 2006, pp. 289-292; Copeland et
al. 2007, p. 2211). In one study, wolverines did not strongly avoid
developed habitat within their home ranges (May et al 2006, p. 289).
Wolverines may respond positively to human activity and developments
that are a source of food. They scavenge food at dumps in and adjacent
to urban areas, at trapper cabins, and at mines (LeResche and Hinman
1973 as cited in Banci 1994, p. 115; Banci 1994, p. 99).
Wolverine dispersal may also be affected by development. Linkage
zones are places where animals can find food, shelter, and security
while moving across the landscape between suitable habitats. Wolverines
prefer to travel in habitat that is most similar to habitat they use
for home-range establishment, i.e., alpine habitats that maintain snow
cover well into the spring (Schwartz et al. 2009, p. 3227). Wolverines
may move large distances in an attempt to establish new home ranges,
but the probability of making such movements decreases with increased
distance between suitable habitat patches, and the degree to which the
characteristics of the habitat to be traversed diverge from preferred
habitat (Copeland et al. 2010, entire; Schwartz et al. 2009, p. 3230).
Wolverine populations in the northern Rocky Mountains appear to be
connected to each other at the present time through dispersal routes
that correspond to habitat suitability (Schwartz et al. 2009, Figures
4, 5).
The level of development in these linkage areas that wolverines can
tolerate is unknown, but it appears that the current landscape does
allow some
[[Page 78048]]
wolverine dispersal (Schwartz et al. 2009, Figures 4, 5; Moriarty et
al. 2009, entire; Inman et al. 2009, pp. 22-28). However, contiguous
U.S. gene flow between populations may not be high enough to prevent
genetic drift (Cegelski et al. 2006, p. 208). Each subpopulation within
the contiguous United States would need an estimated 400 breeding
pairs, or 1 to 2 effective migrants per generation, to ensure long-term
genetic viability (Cegelski et al. 2006, p. 209). Our current
understanding of wolverine ecology suggests that no subpopulation
historically or presently at carrying capacity would approach 400
breeding pairs within the contiguous United States (Brock et al. 2007,
p. 26); nor is the habitat capable of supporting anywhere near this
number. It is highly unlikely that 400 breeding pairs exist in the
entire contiguous United States. For this reason, long-term viability
of wolverines in the contiguous United States requires exchange of
individuals between blocks of habitat.
Wolverines are capable of long-distance movements through variable
and anthropogenically altered terrain, crossing numerous transportation
corridors (Moriarty et al. 2009, entire; Inman et al. 2009, pp. 22-28).
Wolverines are able to successfully disperse between habitats, despite
the level of development that is currently taking place in the northern
Rocky Mountains (Copeland 1996, p. 80; Copeland and Yates 2006, pp. 17-
36; Inman et al. 2007a, pp. 9-10; Pakila et al. 2007, pp. 105-109;
Schwartz et al. 2009, Figures 4, 5). Dispersal between populations is
needed to avoid further reduction in genetic diversity; however, it is
not clear that development or human activities are preventing wolverine
movements between suitable habitat patches rather than simply small
population sizes making movements infrequent. Future human developments
may increase landscape resistance to wolverine dispersal; however, we
have no information to suggest that this situation is likely to reach a
level of impeding wolverine movements within the foreseeable future.
Infrastructure developments that occur within wolverine habitat will
affect wolverines in local areas and those impacts should be accounted
for during planning activities. Infrastructure development, by itself,
does not threaten the wolverine DPS; however, it may act in concert
with the primary threat of climate change to further depress wolverine
populations as habitats become more restricted.
Transportation Corridors
Transportation corridors may affect wolverines if located in
wolverine habitat or between habitat patches. If located in wolverine
habitat, transportation corridors result in direct loss of habitat and
possibly displacement of wolverines for some distance. Direct mortality
due to collisions with vehicles is also possible. Transportation
corridors provide access to areas otherwise not affected by humans,
which exacerbates the effects of human disturbance from a variety of
activities. Outside of wolverine habitat, transportation corridors may
affect wolverines if they present barriers to movement between habitat
patches or result in direct mortality to dispersing wolverines. Because
wolverines are capable of making long-distance movements between
patches of suitable habitat, transportation corridors located many
miles away from wolverine home ranges may affect their ability to
disperse or recolonize vacant habitats after local extirpation events.
The Trans Canada Highway at Kicking Horse Pass in southern British
Columbia, an important travel corridor over the Continental Divide, has
a negative effect on wolverine movement (Austin 1998, p. 30).
Wolverines partially avoided areas within 100 m (328 ft) of the
highway, and preferred distant sites (greater than 1,100 m (3,608 ft)).
Wolverines that approached the highway to cross repeatedly retreated
and successful crossing occurred in only half of the attempts. Where
wolverines did successfully cross, they used the narrowest portions of
the highway right-of-way. Although not assessed, disturbance-related
effects of the highway may have been greater in summer when traffic
volumes were higher. A railway with minimal human activity, adjacent to
the highway, had little effect on wolverine movements. Wolverines did
not avoid, and even preferred, compacted, lightly-used ski trails in
the area.
In the tri-State area of Idaho, Montana, and Wyoming, most
crossings of Federal or State highways are done by subadult wolverines
making exploratory or dispersal movements (ranges of resident adults
typically did not contain major roads) (Packila et al. 2007, p. 105).
Roads in the study area, typically 2-lane highways or roads with less
improvement, were not absolute barriers to wolverine movement. The
wolverine that moved to Colorado from Wyoming in 2008 successfully
crossed Interstate 80 in southern Wyoming (Inman et al. 2008, Figure
6). Wolverines in Norway successfully cross deep valleys that contain
light human developments such as railway lines, settlements, and roads
(Landa et al. 1998, p. 454). Wolverines in central Idaho avoided
portions of a study area that contained roads, although this was
possibly an artifact of unequal distribution of roads that occurred at
low elevations and peripheral to the study site (Copeland et al. 2007,
p. 2211). Wolverines frequently used un-maintained roads for traveling
during the winter, and did not avoid trails used infrequently by people
or active campgrounds during the summer.
At both a site-specific and landscape scale, wolverine natal dens
were located particularly distant from public (greater than 7.5 km (4.6
mi)) and private (greater than 3 km (1.9 mi)) roads (May 2007, p. 14-
31). Placement of dens away from public roads (and away from associated
human-caused mortality) was a positive influence on successful
reproduction (May 2007, p. 14-31). Predictive, broad-scale habitat
models, developed using historic records of wolverine occurrence,
indicated that roads were negatively associated with wolverine
occurrence (Rowland et al. 2003, p. 101). Although wolverines appear to
avoid transportation corridors in their daily movements, the low
density of these types of structures in wolverine habitat leads us to
conclude that the effects are most likely local in scale. Development
of transportation corridors in linkage areas may inhibit wolverine
movements between habitat patches, potentially reducing connectivity
among habitat islands. This isolating effect has not been measured for
wolverines and remains theoretical at this point in time.
Transportation corridors, by themselves, do not threaten the wolverine
DPS, however, these corridors may work in concert with the primary
threat of climate change to further depress populations or reduce
habitat connectivity as habitat becomes more restricted. Therefore, we
consider transportation corridors to be a potential threat to the
wolverine DPS, in concert with the primary threat of climate change.
Land Management
Effects to wolverines from land management actions such as grazing,
timber harvest, and prescribed fire are largely unknown. Wolverines in
British Columbia used recently logged areas in the summer and moose
winter ranges for foraging (Krebs et al. 2007, pp. 2189-2190). Although
males did not appear to be influenced strongly by the presence of
roadless areas, the researchers did not measure traffic volume, so may
have been unable to detect responses of males
[[Page 78049]]
to heavily used roads. In Idaho, wolverines used recently burned areas
despite the loss of canopy cover (Copeland 1996, p. 124).
Intensive management activities such as timber harvest and
prescribed fire do occur in wolverine habitat; however, for the most
part, wolverine habitat tends to be located at high elevations and in
rugged topography that is unsuitable for intensive timber management.
Much of wolverine habitat is managed by the U.S. Forest Service or
other Federal agencies and is protected from some practices or
activities such as residential development. In addition, much of
wolverine habitat within the contiguous United States is already in a
management status such as wilderness or national park (see Factor D for
more discussion) that provides some protection from management,
industrial, and recreational activities. Wolverines are not thought to
be dependent on specific vegetation or habitat features that might be
manipulated by land management activities. We conclude that land
management activities as discussed above do not constitute a threat to
the wolverine DPS.
Summary of Factor A
The threat of past, current, and future climate change occurs over
the entire range of the contiguous U.S. population of the wolverine.
This threat is likely to have already reduced the overall areal extent
and distribution of wolverine suitable habitat. Determining whether or
not wolverine populations have been impacted by this threat is
complicated by the historical extirpation of wolverines in the early
20th Century followed by recolonization and expansion. It is possible
that expansion of wolverine populations through the second half of the
20th Century has masked climate change effects that would have
otherwise reduced populations had they existed at presettlement levels.
So despite the lack of detectable population-level impacts, it is still
likely that habitat is already reduced from historic levels due to this
threat.
Future climate changes are projected to reduce suitable wolverine
habitat by 23 percent by 2045 and 63 percent by the time interval
between 2070 and 2099 due to climate warming. This reduction will
likely result in suitable wolverine habitat shifting up mountain
slopes, and, due to the conical structure of mountains, will result in
smaller, more isolated remaining habitat patches. Due to the large size
of wolverine home ranges, many small mountain ranges are likely to lose
the ability to support wolverine populations. We expect that, due to
secondary effects of this habitat loss such as increased habitat
fragmentation and isolation, the impacts of habitat loss on wolverines
will be greater than the areal extent of habitat loss.
Deep snow that persists into the month of May is essential for
wolverine reproduction. This life-history need is likely to be most
sensitive to climate changes. Wolverine are vulnerable to habitat
modification (specifically, reduction in persistent spring snow cover)
due to climate warming in the contiguous United States. Further, it is
likely that year-round wolverine habitat, not just denning habitat,
will also be significantly reduced due to the effects of climate
warming. Reductions in habitat would result in greater habitat
isolation, reducing the frequency of dispersal between habitat patches
and the likelihood of recolonization after local extinction events.
This reduced dispersal ability is likely to result in loss of genetic
diversity within remaining habitat patches and population loss due to
demographic stochasticity. The contiguous U.S. population of wolverines
is already very small and fragmented and is, therefore, particularly
vulnerable to these impacts, to the extent that the degree of these
impacts could lead to endangerment of the DPS within the foreseeable
future.
The best available scientific and commercial information shows that
the impacts of climate change will continue within the foreseeable
future. Due to the magnitude and extent of the effects of climate
change, we conclude that climate change constitutes a significant
threat to the contiguous U.S. DPS of the wolverine in the foreseeable
future.
Collectively, human activities, including dispersed recreation
activities, infrastructure, and the presence of transportation
corridors, may result in reduced habitat value for wolverines. However,
the alpine and subalpine habitats preferred by wolverine typically
receive little human use relative to lower elevation habitats. The
evidence at this time does not lead us to determine that human
activities and developments by themselves pose a current threat to
wolverines in the contiguous United States. The majority of wolverine
habitat (90 percent) occurs within Forest Service and National Park
Service lands that are subject to disturbance but not direct habitat
loss to infrastructure development. The lack of information concerning
the distribution and intensity of human activities, especially
dispersed recreational activities, precludes us from determining they
currently pose a threat to wolverines.
Wolverines can coexist with some modification of their environment,
as wilderness characteristics such as complete lack of motorized use or
any permanent human presence are likely not critical for maintenance of
populations. It is clear that wolverines can coexist with some level of
human disturbance and habitat modification. How much is too much is not
known. The proximity of wolverine habitats to areas heavily or
moderately used for dispersed recreation needs more study, especially
where there is overlap during the denning season. Effects of these
activities on wolverine vital rates are unknown.
We know of no examples where large areas of habitat, the size of a
wolverine's home range or larger, have been rendered unsuitable due to
human activities such as dispersed recreation. However, given the
sensitivity of wolverines during the denning season and the increasing
intensity of dispersed recreational activities in and around wolverine
habitats, we believe this is an area that warrants further study so
that determinations made in the future may be on firmer scientific
ground.
The effects of direct human disturbance associated with habitat
modifications and usage occur throughout the range of wolverines.
Little scientific or commercial information indicate effects to
wolverines from habitat modifications, development, or human
disturbances associated with them. What little information exists
suggests that wolverines can adjust to moderate habitat modification,
infrastructure development, and human disturbance. In addition, large
amounts of wolverine habitat are protected from human disturbances and
development, either legally through wilderness and National Park
designation, or by being located at remote and high-elevation sites.
Therefore, wolverines are afforded a relatively high degree of
protection from the effects of human activities by the nature of their
habitat. Wolverines are known to successfully disperse long distances
between habitats through human-dominated landscapes and across
transportation corridors. The current level of residential, industrial,
and transportation development in the western United States does not
appear to have precluded the long-distance dispersal movements that
wolverines require for maintenance of genetic diversity.
The impacts of climate change constitute a threat to the contiguous
U.S. DPS of the wolverine, and will likely be irreversible within the
foreseeable future. Due to the magnitude
[[Page 78050]]
and extent of the effects of climate change, we find that the
contiguous U.S. DPS of the North American wolverine is likely to become
in danger of extinction in the foreseeable future due to destruction,
modification, and curtailment of its habitat and range by climate
change.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Over much of recent history, trapping has been a primary cause of
wolverine mortality (Banci 1994, p. 108; Krebs et al. 2004, p. 497;
Lofroth and Ott 2007, pp. 2196-2197; Squires et al. 2007, p. 2217).
Unregulated trapping is believed to have played a role in the historic
decline of wolverines in North America in the late 1800s and early
1900s (Hash 1987, p. 580). Wolverines are especially vulnerable to
targeted trapping and predator reduction campaigns due to their habit
of ranging widely in search of carrion, which would bring them into
frequent contact with poison baits and traps (Copeland 1996, p. 78;
Inman et al. 2007a, pp. 4-10; Packila et al. 2007, p. 105; Squires et
al. 2007, p. 2219).
Human-caused mortality of wolverines is likely additive to natural
mortality due to the low reproductive rate and relatively long life
expectancy of wolverines (Krebs et al. 2004, p. 499; Lofroth and Ott
2007, pp. 2197-2198; Squires et al. 2007, pp. 2218-2219). This means
that trapped populations likely live at densities that are lower than
carrying capacity, and may need to be reinforced by recruits from
untrapped populations to maintain population viability and persistence.
A study in British Columbia determined that, under a regulated
trapping regime, trapping mortality in 15 of 71 wolverine population
units was unsustainable, and that populations in those unsustainable
population units are dependent on immigration from neighboring
populations or untrapped refugia (Lofroth and Ott 2007, pp. 2197-2198).
Similarly, in southwestern Montana, intensive legal trapping in
isolated mountain ranges reduced local populations and was the dominant
form of mortality for the duration of the study (Squires et al. 2007,
pp. 2218-2219). The harvest levels observed, which included two
pregnant females in a small mountain range, could have significant
negative effects on a small population (Squires et al. 2007, p. 2219).
Harvest refugia, such as national parks and large wilderness, are
important to wolverine persistence on the landscape because they can
serve as sources of surplus individuals to bolster trapped populations
(Squires et al. 2007, p. 2219; Krebs and Ott 2004, p. 500). Glacier
National Park, though an important refuge for a relatively robust
population of wolverines, was still vulnerable to trapping because most
resident wolverine home ranges extended into large areas outside the
Park (Squires et al. 2007, p. 2219).
Despite the impacts of trapping on wolverines in the past, trapping
is no longer a threat within most of the wolverine range in the
contiguous United States. Montana is the only State where wolverine
trapping is still legal. Before 2004, average wolverine harvest was
10.5 wolverines per year. Due to preliminary results of the study
reported in Squires et al. (2007, pp. 2213-2220), the Montana
Department of Fish, Wildlife, and Parks adopted new regulations for the
2004-2005 trapping season that divided the State into three units, with
the goal of spreading the harvest more equitably throughout the State.
For the 2008-2009 trapping season, Montana Department of Fish,
Wildlife, and Parks adjusted its wolverine trapping regulations again
to further increase the geographic control on harvest to prevent
concentrated trapping in any one area, and to completely stop trapping
in isolated mountain ranges where small populations are most vulnerable
(Montana Department of Fish Wildlife and Parks 2010, pp. 8-11). Their
new regulations spread harvest across three geographic units (the
Northern Continental Divide area, the Greater Yellowstone area, and the
Bitterroot Mountains), and establish a statewide limit of 5 wolverines.
The 2008-2009 and 2009-2010 trapping seasons have resulted in four and
three wolverines harvested, respectively (Montana Department of Fish
Wildlife and Parks 2010, pp. 8-11). Under the current regulations, no
more than three female wolverines can be legally harvested each year,
and harvest in the more vulnerable isolated mountain ranges is
prohibited.
Montana Department of Fish, Wildlife, and Parks conducts yearly
monitoring using track surveys. Their protocol does not utilize
verification methods such as DNA collection or camera stations to
confirm identifications. Consequently, misidentifications are likely to
occur. Given the relative rarity of wolverines and the relative
abundance of other species with which they may be confused, such as
bobcats, lynx, and bears, lack of certainty of identifications of
tracks makes it highly likely that the rare species is over-represented
in unverified tracking records (McKelvey et al. 2008, entire). The
Montana Department of Fish, Wildlife, and Parks wolverine track survey
information does not meet our standard for verifiable or documented
occurrence records described in the geographic distribution section,
and we have not relied on this information in this finding.
Montana wolverine populations have rebounded from historic lows in
the early 1900s while at the same time being subject to regulated
trapping (Aubry et al. 2007, p. 2151; Montana Department of Fish,
Wildlife, and Parks 2007, p. 1). In fact, much of the wolverine
expansion that we have described above took place under less-
restrictive harvest regulations than are in place today. Through their
refinement of harvest regulations over the past 10 years, Montana
Department of Fish, Wildlife, and Parks has demonstrated its commitment
to adjust harvest management when evidence indicates it is necessary
for conserving wolverine populations. Therefore, we conclude that, in
the absence of other threats, harvest would not be likely to threaten
State-wide wolverine populations in Montana, or to threaten the
continued existence of the wolverine population in the contiguous
United States. However, the additive mortality caused by trapping could
become a concern in the future as the size of the wolverine population
shrinks in response to the loss of habitat due to climate change
described above.
Current levels of incidental trapping (i.e., capture in traps set
for species other than wolverine) and poisoning have been suggested to
be a threat to wolverines, but no supporting information for this
assertion is available.
Summary of Factor B
Wolverine harvest affects one of the four States within the current
range of North American wolverines in the contiguous United States.
However, the State of Montana contains most of the habitat and
wolverines that exist in the four States, and regulates trapping to
reduce the impact of harvest on wolverine populations. We do not
believe that the level of harvest in Montana, by itself, is a threat
that causes the species within the contiguous United States to be in
danger of extinction or likely to become in danger of extinction in the
foreseeable future.
Harvest, when combined with the other threats outlined in this
finding, may contribute to the likelihood that the wolverine will
become extirpated in the foreseeable future by increasing the speed
with which small populations of wolverine are lost from isolated
habitats, and also by increasing
[[Page 78051]]
mortality levels for dispersing wolverines that are required to
maintain the genetics and demographics of wolverine populations in the
contiguous United States. The willingness of the Montana Department of
Fish, Wildlife, and Parks to adjust wolverine harvest management in
reaction to new scientific information on the status of wolverines
leads us to believe that the agency will continue to adjust harvest
levels as needed, including suspension of harvest altogether should
populations decline.
Factor C. Disease or Predation
Limited information is currently available on the potential effects
of disease on wolverine populations. Wolverines are sometimes killed by
wolves, black bears, and puma (Burkholder 1962, p. 264; Hornocker and
Hash 1981, p. 1296; Copeland 1996, p. 44-46; Inman et al. 2007d, p.
89). In addition, wolverine reproductive dens are likely subject to
predation, although so few dens have been discovered in North America
that determining the intensity of this predation is not possible.
Summary of Factor C
Wolverine mortality from predation and disease do not appear to be
above natural or sustainable levels, such that these factors would
cause the species within the contiguous United States to be in danger
of extinction or likely to become in danger of extinction in the
foreseeable future.
Factor D. Inadequacy of Existing Regulatory Mechanisms
The majority (95 percent) of wolverine habitat currently occupied
by wolverine populations in the lower contiguous United States is
Federally owned and managed, mostly (90 percent) by the Forest Service.
An estimated 126,302 km \2\ (49,258 mi \2\) of wolverine habitat occurs
in Montana, Idaho, and Wyoming. Of that, 120,000 km \2\ (46,332 mi \2\)
is in Federal ownership and 109,000 km \2\ (42,085 mi \2\) of that is
managed by the Forest Service. Additionally, 33,263 km (12,973 mi \2\)
(26.3 percent) occurs in designated wilderness; 4,180 km \2\ (1,630 mi
\2\) (3.3 percent) are in wilderness study areas. An additional 8,432
km \2\ (3,288 mi \2\) (6.7 percent) are within national parks (Brock et
al. 2007, pp. 33-35; Inman 2007b, pers. comm.). Thus, a total of 36.3
percent of the estimated wolverine habitat in the three-State area
occurs in locations with high levels of protection.
No Federal or State regulatory mechanisms exist that address the
threat of modification of wolverine habitat due to climate change.
Several mechanisms exist that protect wolverine from other forms of
disturbance and from overutilization from harvesting; these are
described in more detail below.
Federal Laws and Regulations
The Wilderness Act
The Forest Service and National Park Service both manage lands
designated as wilderness areas under the Wilderness Act of 1964 (16
U.S.C. 1131-1136). Within these areas, the Wilderness Act states the
following: (1) New or temporary roads cannot be built; (2) there can be
no use of motor vehicles, motorized equipment, or motorboats; (3) there
can be no landing of aircraft; (4) there can be no other form of
mechanical transport; and (5) no structure or installation may be
built. A large amount of suitable wolverine habitat occurs within
Federal wilderness areas in the United States (Inman, personal
communication 2007b). As such, a large proportion of existing wolverine
habitat is protected from direct loss or degradation by the
prohibitions of the Wilderness Act.
National Environmental Policy Act
All Federal agencies are required to adhere to the National
Environmental Policy Act (NEPA) of 1970 (42 U.S.C. 4321 et seq.) for
projects they fund, authorize, or carry out. The Council on
Environmental Quality's regulations for implementing NEPA (40 CFR parts
1500-1518) state that agencies shall include a discussion on the
environmental impacts of the various project alternatives (including
the proposed action), any adverse environmental effects which cannot be
avoided, and any irreversible or irretrievable commitments of resources
involved (40 CFR part 1502). The NEPA itself is a disclosure law, and
does not require subsequent minimization or mitigation measures by the
Federal agency involved. Although Federal agencies may include
conservation measures for wolverines as a result of the NEPA process,
any such measures are typically voluntary in nature and are not
required by the statute. Additionally, activities on non-Federal lands
are subject to NEPA if there is a Federal nexus.
For example, wolverines are designated as a sensitive species by
the Forest Service, which requires that effects to wolverines be
considered in documentation completed under NEPA. NEPA does not itself
regulate activities that might affect wolverines, but it does require
full evaluation and disclosure of information regarding the effects of
contemplated Federal actions on sensitive species and their habitats.
National Forest Management Act
Under the National Forest Management Act of 1976, as amended (16
U.S.C. 1600-1614), the Forest Service shall strive to provide for a
diversity of plant and animal communities when managing national forest
lands. Individual national forests may identify species of concern that
are significant to each forest's biodiversity. It is unknown what level
of protection, if any, each of the individual national forests offer
for wolverines. In many of the States in which wolverines are found,
wolverines occur in wilderness areas and are thus protected under the
Wilderness Act. Outside of wilderness but still on Forest Service-
managed lands, wolverines occur mainly in alpine areas, which are
sensitive to negative habitat alterations. Their habitat is generally
offered more protections from harvest or road building than would
otherwise be the case in lowland areas.
National Park Service Organic Act
The NPS Organic Act of 1916 (16 U.S.C. 1 et seq.), as amended,
states that the NPS ``shall promote and regulate the use of the Federal
areas known as national parks, monuments, and reservations to conserve
the scenery and the national and historic objects and the wildlife
therein and to provide for the enjoyment of the same in such manner and
by such means as will leave them unimpaired for the enjoyment of future
generations.'' Where wolverines occur in National Parks, they and their
habitats are protected from large-scale loss or degradation due to the
Park Service's mandate to ``* * * conserve scenery * * * and wildlife *
* * [by leaving] them unimpaired.''
Clean Air Act of 1970
The petitioners claim that wolverines are threatened by a lack of
regulatory mechanisms to curb greenhouse gases that contribute to
global temperature rises (Wolf et al. 2007, p. 50). As stated earlier
under Factor A, our status review did reveal information that increased
temperatures and loss of persistent spring snow are a significant
threat to wolverines across the DPS range in the foreseeable future. No
existing regulatory mechanisms adequately address global climate
change. The Clean Air Act of 1970 (42 U.S.C. 7401 et seq.), as amended,
requires the Environmental Protection Agency (EPA) to develop and
enforce regulations to protect the general public from exposure
[[Page 78052]]
to airborne contaminants that are known to be hazardous to human
health. In 2007, the Supreme Court ruled that gases that cause global
warming are pollutants under the Clean Air Act, and that the EPA has
the authority to regulate carbon dioxide and other heat-trapping gases
(Massachusetts et al. v. EPA 2007 [Case No. 05-1120]). The EPA
published a regulation to require reporting of greenhouse gas emissions
from fossil fuel suppliers and industrial gas suppliers, direct
greenhouse gas emitters, and manufacturers of heavy-duty and off-road
vehicles and engines (74 FR 56260; October 30, 2009). The rule,
effective December 29, 2009, does not require control of greenhouse
gases; rather it requires only that sources above certain threshold
levels monitor and report emissions (74 FR 56260; October 30, 2009). On
December 7, 2009, the EPA found under section 202(a) of the Clean Air
Act that the current and projected concentrations of six greenhouse
gases in the atmosphere threaten public health and welfare. The finding
itself does not impose requirements on any industry or other entities
but is a prerequisite for any future regulations developed by the EPA.
At this time, it is not known what regulatory mechanisms will be
developed in the future as an outgrowth of the finding or how effective
they would be in addressing climate change.
State Laws and Regulations
State Comprehensive Wildlife Conservation Strategies and State
Environmental Policy and Protection Acts
The wolverine is listed as State Endangered in Washington,
California, and Colorado. In Idaho and Wyoming it is designated as a
protected nongame species (Idaho Department of Fish and Game 2010, p.
4; Wyoming Game and Fish 2005, p. 2). Oregon, while currently not
considered to have any individuals other than possible unsuccessful
dispersers, has a closed season on trapping of wolverines. These
designations largely protect the wolverine from mortality due to
hunting and trapping. In Montana, the wolverine is classified as a
regulated furbearer (Montana Fish, Wildlife, and Parks 2010, p. 8).
Montana is the only State in the contiguous United States where
wolverine trapping is still legal.
Wolverines receive some protection under State laws in Washington,
California, Idaho, Montana, Wyoming, and Colorado. Each State's fish
and wildlife agency has some version of a State Comprehensive Wildlife
Conservation Strategy (CWCS) in place. These strategies, while not
State or national legislation can help prioritize conservation actions
within each State. Named species and habitats within each CWCS may
receive focused attention during State Environmental Protection Act
(SEPA) reviews as a result of being included in a State's CWCS.
However, only Washington, California, and Montana appear to have SEPA-
type regulations in place. In addition, each State's fish and wildlife
agency often specifically names or implies protection of wolverines in
their hunting and trapping regulations. Only the State of Montana
currently allows wolverine harvest.
Before 2004, the Montana Department of Fish, Wildlife, and Parks
regulated wolverine harvest through the licensing of trappers, a bag
limit of one wolverine per year per trapper, and no statewide limit.
Under this management, average wolverine harvest was 10.5 wolverines
per year. Due to preliminary results of the study reported in Squires
et al. (2007, pp. 2213-2220), Montana Department of Fish, Wildlife, and
Parks adopted new regulations for the 2004-2005 trapping season that
divided the State into three units with the goal of spreading the
harvest more equitably throughout the State. In 2008, Montana
Department of Fish, Wildlife, and Parks further refined their
regulations to prohibit trapping in isolated mountain ranges, and
reduced the overall statewide harvest to 5 wolverines with a statewide
female harvest limit of 3. We conclude that trapping in Montana, by
itself, is not a threat to the wolverine DPS, but that by working in
concert with the primary threat of climate change, the trapping program
may contribute to population declines caused by other threats.
Therefore, we conclude that wolverine harvest is a secondary threat to
wolverines.
Summary of Factor D
The existing regulatory mechanisms appear to protect wolverine from
several of the threats described in Factors A through C above.
Specifically, State regulations for wolverine harvest appear to be
sufficient to prohibit range-wide overutilization from hunting and
trapping in the absence of other threats. Federal ownership of much of
occupied wolverine habitat protects the species from direct losses of
habitat and provides further protection from many of the forms of
disturbance described above. Wolverines can use habitats affected by
moderate levels of human disturbance, and additional protection is
afforded wolverines by the significant portion of their range that
occurs in designated wilderness and national parks. The current
regulatory regime does not address the potential impacts of dispersed
winter recreation; however, at this time the available information does
not suggest that dispersed winter recreation is a threat. That being
the case, all of these potential threats are likely to have local
impacts on wolverines, and cumulatively, they may act in concert with
the primary threat of climate change to threaten wolverine populations.
Therefore, we conclude it is appropriate to view them as secondary
threats to the wolverine DPS.
Our review of the regulatory mechanisms in place at the national
and State level demonstrates that the short-term, site-specific threats
to wolverine from direct loss of habitat, disturbance by humans, and
direct mortality from hunting and trapping are, for the most part,
adequately addressed through State and Federal regulatory mechanisms.
However, as described under Factor A, the primary threat with the
greatest severity and magnitude of impact to the species is loss of
habitat due to continuing climate warming. No known regulatory
mechanisms are currently in place at the national or international
level that effectively address this threat to wolverine habitat from
climate change. Therefore, the current inadequacy of regulatory
mechanisms to protect wolverines and their habitat is a threat to the
DPS.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Small Population Size
Wolverines in the contiguous United States are thought to be
derived from a recent re-colonization event after they were extirpated
from the area in the early 20th century (Aubry et al. 2007, Table 1,
Michael Schwartz, pers. comm.). Consequently, wolverine populations in
the contiguous United States have reduced genetic diversity relative to
larger Canadian populations as a result of founder effects or
inbreeding (Schwartz et al. 2009, pp. 3228-3230). As described in the
DPS analysis above, wolverine effective population size in the
contiguous United States is exceptionally low (Schwartz 2007, pers.
comm.) and is below what is thought to be adequate for short-term
maintenance of genetic diversity. Loss of genetic diversity can lead to
inbreeding depression and is associated with increased risk of
extinction (Allendorf and Luikart 2007, pp. 338-343). Effective
population size is important because it determines rates of loss of
genetic variation, fixation of deleterious alleles, and the rate of
[[Page 78053]]
inbreeding. Small effective population sizes are caused by small actual
population size (census size), or by other factors that limit the
genetic contribution of portions of the population, such as polygamous
mating systems. Populations may increase their effective size by
increasing census size or by the regular exchange of genetic material
with other populations through inter-population mating. Populations
with small effective population sizes show reductions in population
growth rates and increases in extinction probabilities (Leberg 1990, p.
194; Jimenez et al. 1994, pp. 272-273; Newman and Pilson 1997, p. 360;
Saccheri et al. 1998, p. 492; Reed and Bryant 2000, p. 11; Schwartz and
Mills 2005, p. 419; Hogg et al. 2006, p. 1495, 1498; Allendorf and
Luikart 2007, pp. 338-342).
The concern with the low effective population size was highlighted
in a recent analysis which determined that without immigration from
other populations at least 400 breeding pairs would be necessary to
sustain the long-term genetic viability of the contiguous U.S.
wolverine population (Cegelski et al. 2006, p. 197). However, the
entire population is likely only 250 to 300 (Inman 2010b, pers. comm.),
with a substantial number of these being unsuccessful breeders or
nonbreeding subadults.
Genetic studies demonstrate the essential role that genetic
exchange plays in maintaining genetic diversity in small wolverine
populations. The concern that low effective population size would
result in negative effects is already being realized for the contiguous
U.S. population of wolverine. Genetic drift has already occurred in
subpopulations of the contiguous United States: wolverines here
contained 3 of 13 haplotypes found in Canadian populations (Kyle and
Strobeck 2001, p. 343; Cegelski et al. 2003, pp. 2914-2915; Cegelski et
al. 2006, p. 208; Schwartz et al. 2007, p. 2176; Schwartz et al. 2009,
p. 3229). The haplotypes found in these populations were a subset of
those in the larger Canadian population, indicating that genetic drift
had caused a loss of genetic diversity. One study found that a single
haplotype dominated the northern Rocky Mountain wolverine population,
with 71 of 73 wolverines sampled expressing that haplotype (Schwartz et
al. 2007, p. 2176). The reduced number of haplotypes indicates not only
that genetic drift is occurring but some level of genetic separation;
if these populations were freely interbreeding, they would share more
haplotypes (Schwartz et al. 2009, p. 3229). The reduction of haplotypes
is likely a result of the fragmented nature of wolverine habitat in the
United States and is consistent with an emerging pattern of reduced
genetic variation at the southern edge of the range documented in a
suite of boreal forest carnivores (Schwartz et al. 2007, p. 2177).
Immigration of wolverines from Canada is not likely to bolster the
genetic diversity of wolverines in the contiguous United States. There
is an apparent lack of connectivity between wolverine populations in
Canada and the United States based on genetic data (Schwartz et al.
2009, pp. 3228-3230). The apparent loss of connectivity between
wolverines in the northern Rocky Mountains and Canada prevents the
influx of genetic material needed to maintain or increase the genetic
diversity in the contiguous United States. The continued loss of
genetic diversity may lead to inbreeding depression, potentially
reducing the species' ability to persist through reduced reproductive
output or reduced survival. Currently, the cause for this lack of
connectivity is uncertain, and existing regulatory mechanisms may be
inadequate to address population connectivity. Wolverine habitat
appears to be well-connected across the border region (Copeland et al.
2010, Figure 2) and there are few man-made obstructions such as
transportation corridors or alpine developments. However, this lack of
genetically detectable connectivity may be related to harvest
management in southern Canada. The current inadequacy of existing
regulatory mechanisms to address connectivity across the international
boundary may pose a risk to wolverines in the contiguous United States
in the future through reduced effective population size resulting in
potential loss of genetic diversity through inbreeding.
Summary of Factor E
Small population size and inbreeding depression are potential
threats to wolverines in the contiguous United States. There is good
evidence that genetic diversity is lower in wolverines in the DPS than
it is in the more contiguous habitat in Canada and Alaska. The
significance of this lower genetic diversity to wolverine conservation
is unknown. We do not discount the possibility that loss of genetic
diversity could be negatively affecting wolverines now and will
continue to do so in the future. It is important to point out however,
that wolverine populations in the DPS area are thought to be the result
of colonization events that have occurred since the 1930s. Such recent
colonizations by relatively few individuals and subsequent population
growth are likely to have resulted in founder effects, which could have
contributed to the low genetic diversity. The threat of small
population sizes and low genetic diversity is likely to become more
significant if populations become smaller and more isolated, as
predicted due to climate changes. Restoration of connectivity with
Canadian populations may require international cooperation to establish
appropriate control of exploitation in the international border region.
Therefore, it is our determination that small population size and
inbreeding depression are a secondary threat to the DPS that may
contribute to wolverine declines, especially as projected climate
changes reduce overall habitat size and connectivity between habitat
patches.
Finding
As required by the Act, we conducted a review of the status of the
DPS and considered the five factors in assessing whether wolverines in
the contiguous United States are threatened or endangered throughout
all or a significant portion of their range. We examined the best
scientific and commercial information available regarding the past,
present, and future threats faced by wolverines. We reviewed the
petition, information available in our files, other available published
and unpublished information, and we consulted with wolverine and
wolverine habitat experts and other Federal, State, and tribal
agencies. In considering what factors might constitute threats, we must
look beyond the mere exposure of the species to the factor to determine
whether the species responds to the factor in a way that causes actual
impacts to the species. If there is exposure to a factor, but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species such that the species warrants
listing as threatened or endangered as those terms are defined by the
Act. This does not necessarily require empirical proof of a threat. The
combination of exposure and some corroborating evidence of how the
species is likely impacted could suffice. The mere identification of
factors that could impact a species negatively is not sufficient to
compel a finding that
[[Page 78054]]
listing is appropriate; we require evidence that these factors are
operative threats that act on the species to the point that the species
meets the definition of threatened or endangered under the Act.
This status review identified threats to the contiguous U.S.
population of the North American wolverine attributable to Factors A,
B, D, and E. The primary threat to the DPS is from habitat and range
loss due to climate warming (Factor A). Wolverines inhabit habitats
with near-arctic conditions wherever they occur. In the contiguous
United States, wolverine habitat is restricted to high-elevation areas
in the West. Wolverines are dependent on deep persistent snow cover for
successful denning, and they concentrate their year-round activities in
areas that maintain deep snow into spring and cool temperatures
throughout summer. Wolverines in the contiguous United States exist as
small and semi-isolated subpopulations in a larger metapopulation that
requires regular dispersal of wolverines between habitat patches to
maintain itself. These dispersers achieve both genetic enrichment and
demographic support of recipient populations. Climate changes are
predicted to reduce wolverine habitat and range by 23 percent over the
next 30 years and 63 percent over the next 75 years, rendering
remaining wolverine habitat significantly smaller and more fragmented.
We anticipate that, by 2045, maintenance of the contiguous U.S.
wolverine population in the currently occupied area will require human
intervention to facilitate genetic exchange and possibly also
facilitate metapopulation dynamics by moving individuals between
habitat patches that are no longer accessed regularly by dispersers.
Other threats are minor in comparison to the driving primary threat of
climate change; however, they could become significant when working in
concert with climate change if they further suppress an already
stressed population. These secondary threats include harvest (Factor
B), disturbance, infrastructure, and transportation corridors (Factor
D), and demographic stochasticity and loss of genetic diversity due to
small effective population sizes (Factor E). All of these factors
affect wolverines across their current range in the contiguous United
States
On the basis of the best scientific and commercial data available,
we find that the petitioned action, to list the North American
wolverine population in the contiguous United States as threatened or
endangered is warranted. We arrive at this determination due to the
current status of wolverines in the contiguous United States, which
exist as a small (250-300 individuals) and genetically depauperate (3
of 13 haplotypes) metapopulation with limited dispersal between
subpopulations. This information, when combined with information about
the primary and secondary threats indicates that wolverines are likely
to lose 63 percent of their current habitat area over the next century.
We will make a determination on the status of the species as threatened
or endangered when we do a proposed listing determination. However, as
explained in more detail below, an immediate proposal of a regulation
implementing this action is precluded by higher priority listing
actions, and progress is being made to add or remove qualified species
from the Lists of Endangered and Threatened Wildlife and Plants.
We reviewed the available information to determine if the existing
and foreseeable threats render the species at risk of extinction now
such that issuing an emergency regulation temporarily listing the
species under section 4(b)(7) of the Act is warranted. We determined
that issuing an emergency regulation temporarily listing the species is
not warranted for this species at this time, because the effects of
climate warming on wolverines and their habitat are expected to unfold
over many years and populations currently appear to be stable or
expanding. However, if at any time we determine that issuing an
emergency regulation temporarily listing the North American wolverine
in the contiguous United States is warranted, we will initiate this
action at that time.
Listing Priority Number
The Service adopted guidelines on September 21, 1983 (48 FR 43098),
to establish a rational system for utilizing available resources for
the highest priority species when adding species to the Lists of
Endangered or Threatened Wildlife and Plants or reclassifying species
listed as threatened to endangered status. These guidelines, titled
``Endangered and Threatened Species Listing and Recovery Priority
Guidelines'' address the immediacy and magnitude of threats, and the
level of taxonomic distinctiveness by assigning priority in descending
order to monotypic genera (genus with one species), full species, and
subspecies (or equivalently, distinct population segments of
vertebrates).
As a result of our analysis of the best available scientific and
commercial information, we assigned wolverines in the contiguous United
States a Listing Priority Number (LPN) of 6 based on our finding that
the DPS faces threats that are of high magnitude but that are not
imminent. The primary threat includes the present or threatened
destruction, modification, or curtailment of wolverine habitat from
climate change; and the secondary threats are associated with Factors
B, D, and E.
Under the Service's guidelines, the magnitude of threat is the
first criterion we look at when establishing a listing priority. The
guidance indicates that species with the highest magnitude of threat
are those species facing the greatest threats to their continued
existence. These species receive the highest listing priority. We
consider the threats that wolverines face to be high in magnitude
because the threat of climate change is present throughout the range of
the DPS.
Under our LPN guidelines, the second criterion we consider in
assigning a listing priority is the immediacy of threats. This
criterion is intended to ensure that the species facing actual,
identifiable threats are given priority over those species for which
threats are only potential or that are intrinsically vulnerable but are
not known to be presently facing such threats. The primary threat
facing the DPS is not imminent. The threat from climate change is
reasonably certain to occur, and its effects may be particularly acute
for small, isolated populations, but we have no evidence that these
effects are imminent (ongoing). The other identified threats were
determined only to be potential threats when acting in concert with the
driving threat of climate change. Therefore, based on our LPN Policy,
the threats are not imminent (ongoing).
The third criterion in our LPN guidelines is intended to devote
resources to those species representing highly distinctive or isolated
gene pools as reflected by taxonomy. We determined wolverines of the
contiguous United States are a valid DPS according to our DPS Policy.
Therefore, under our LPN guidance, the wolverine in the contiguous
United States is assigned a lower priority than a species in a
monotypic genus or a full species that faces the same magnitude and
imminence of threats.
Therefore, we assigned the DPS an LPN of 6 based on our
determination that the DPS faces threats that are overall of high
magnitude but are not imminent. We will continue to monitor the threats
to wolverines in the contiguous United States, and the DPS' status on
an annual basis, and should the magnitude or the imminence of the
[[Page 78055]]
threats change, we will revisit our assessment of LPN.
Preclusion and Expeditious Progress
Preclusion is a function of the listing priority of a species in
relation to the resources that are available and competing demands for
those resources. Thus, in any given fiscal year (FY), multiple factors
dictate whether it will be possible to undertake work on a proposed
listing regulation or whether promulgation of such a proposal is
warranted but precluded by higher priority listing actions.
The resources available for listing actions are determined through
the annual Congressional appropriations process. The appropriation for
the Listing Program is available to support work involving the
following listing actions: Proposed and final listing rules; 90-day and
12-month findings on petitions to add species to the Lists of
Endangered and Threatened Wildlife and Plants (Lists) or to change the
status of a species from threatened to endangered; annual
determinations on prior ``warranted but precluded'' petition findings
as required under section 4(b)(3)(C)(i) of the Act; critical habitat
petition findings; proposed and final rules designating critical
habitat; and litigation-related, administrative, and program-management
functions (including preparing and allocating budgets, responding to
congressional and public inquiries, and conducting public outreach
regarding listing and critical habitat). The work involved in preparing
various listing documents can be extensive and may include, but is not
limited to: Gathering and assessing the best scientific and commercial
data available and conducting analyses used as the basis for our
decisions; writing and publishing documents; and obtaining, reviewing,
and evaluating public comments and peer review comments on proposed
rules and incorporating relevant information into final rules. The
number of listing actions that we can undertake in a given year also is
influenced by the complexity of those listing actions; that is, more
complex actions generally are more costly. For example, during the past
several years, the cost (excluding publication costs) for preparing a
12-month finding, without a proposed rule, has ranged from
approximately $11,000 for one species with a restricted range and
involving a relatively uncomplicated analysis to $305,000 for another
species that is wide-ranging and involving a complex analysis.
We cannot spend more than is appropriated for the Listing Program
without violating the Anti-Deficiency Act (see 31 U.S.C.
1341(a)(1)(A)). In addition, in FY 1998 and for each FY since then,
Congress has placed a statutory cap on funds which may be expended for
the Listing Program, equal to the amount expressly appropriated for
that purpose in that FY. This cap was designed to prevent funds
appropriated for other functions under the Act (for example, recovery
funds for removing species from the Lists), or for other Service
programs, from being used for Listing Program actions (see House Report
105-163, 105th Congress, 1st Session, July 1, 1997).
Recognizing that designation of critical habitat for species
already listed would consume most of the overall Listing Program
appropriation, Congress also put a critical habitat subcap in place in
FY 2002 and has retained it each subsequent year to ensure that some
funds are available for other work in the Listing Program: ``The
critical habitat designation subcap will ensure that some funding is
available to address other listing activities'' (House Report No. 107--
103, 107th Congress, 1st Session, June 19, 2001). In FY 2002 and each
year until FY 2006, the Service has had to use virtually the entire
critical habitat subcap to address court-mandated designations of
critical habitat, and consequently none of the critical habitat subcap
funds have been available for other listing activities. In some FYs
since 2006, we have been able to use some of the critical habitat
subcap funds to fund proposed listing determinations for high-priority
candidate species. In other FYs, while we were unable to use any of the
critical habitat subcap funds to fund proposed listing determinations,
we did use some of this money to fund the critical habitat portion of
some proposed listing determinations so that the proposed listing
determination and proposed critical habitat designation could be
combined into one rule, thereby being more efficient in our work. In FY
2011 we anticipate that we will be able to use some of the critical
habitat subcap funds to fund proposed listing determinations.
We make our determinations of preclusion on a nationwide basis to
ensure that the species most in need of listing will be addressed first
and also because we allocate our listing budget on a nationwide basis.
Through the listing cap, the critical habitat subcap, and the amount of
funds needed to address court-mandated critical habitat designations,
Congress and the courts have in effect determined the amount of money
available for other listing activities nationwide. Therefore, the funds
in the listing cap, other than those needed to address court-mandated
critical habitat for already listed species, set the limits on our
determinations of preclusion and expeditious progress.
Congress identified the availability of resources as the only basis
for deferring the initiation of a rulemaking that is warranted. The
Conference Report accompanying Public Law 97-304, which established the
current statutory deadlines and the warranted-but-precluded finding,
states that the amendments were ``not intended to allow the Secretary
to delay commencing the rulemaking process for any reason other than
that the existence of pending or imminent proposals to list species
subject to a greater degree of threat would make allocation of
resources to such a petition [that is, for a lower-ranking species]
unwise.'' Although that statement appeared to refer specifically to the
``to the maximum extent practicable'' limitation on the 90-day deadline
for making a ``substantial information'' finding, that finding is made
at the point when the Service is deciding whether or not to commence a
status review that will determine the degree of threats facing the
species, and therefore the analysis underlying the statement is more
relevant to the use of the warranted-but-precluded finding, which is
made when the Service has already determined the degree of threats
facing the species and is deciding whether or not to commence a
rulemaking.
In FY 2010, $10,471,000 is the amount of money that Congress
appropriated for the Listing Program (that is, the portion of the
Listing Program funding not related to critical habitat designations
for species that are already listed). Therefore, a proposed listing is
precluded if pending proposals with higher priority will require
expenditure of at least $10,471,000, and expeditious progress is the
amount of work that can be achieved with $10,471,000. Since court
orders requiring critical habitat work will not require use of all of
the funds within the critical habitat subcap, we used $1,114,417 of our
critical habitat subcap funds in order to work on as many of our
required petition findings and listing determinations as possible. This
brings the total amount of funds we had for listing actions in FY 2010
to $11,585,417.
The $11,585,417 was used to fund work in the following categories:
compliance with court orders and court-approved settlement agreements
requiring that petition findings or listing determinations be completed
by a specific date; section 4 (of the Act) listing actions with
absolute statutory deadlines; essential litigation-related,
[[Page 78056]]
administrative, and listing program-management functions; and high-
priority listing actions for some of our candidate species. For FY
2011, on September 29, 2010, Congress passed a continuing resolution
which provides funding at the FY 2010 enacted level. Until Congress
appropriates funds for FY 2011, we will fund listing work based on the
FY 2010 amount. In 2009, the responsibility for listing foreign species
under the Act was transferred from the Division of Scientific
Authority, International Affairs Program, to the Endangered Species
Program. Therefore, starting in FY 2010, we use a portion of our
funding to work on the actions described above as they apply to listing
actions for foreign species. This has the potential to further reduce
funding available for domestic listing actions. Although there are
currently no foreign species issues included in our high-priority
listing actions at this time, many actions have statutory or court-
approved settlement deadlines, thus increasing their priority. The
budget allocations for each specific listing action are identified in
the Service's FY 2011 Allocation Table (part of our administrative
record).
Based on our September 21, 1983, guidance for assigning an LPN for
each candidate species (48 FR 43098), we have a significant number of
species with an LPN of 2. Using this guidance, we assign each candidate
an LPN of 1 to 12, depending on the magnitude of threats (high vs.
moderate to low), immediacy of threats (imminent or nonimminent), and
taxonomic status of the species (in order of priority: monotypic genus
(a species that is the sole member of a genus); species; or part of a
species (subspecies, distinct population segment, or significant
portion of the range)). The lower the listing priority number, the
higher the listing priority (that is, a species with an LPN of 1 would
have the highest listing priority).
Because of the large number of high-priority species, we have
further ranked the candidate species with an LPN of 2 by using the
following extinction-risk type criteria: International Union for the
Conservation of Nature and Natural Resources (IUCN) Red list status/
rank, Heritage rank (provided by NatureServe), Heritage threat rank
(provided by NatureServe), and species currently with fewer than 50
individuals, or 4 or fewer populations. Those species with the highest
IUCN rank (critically endangered), the highest Heritage rank (G1), the
highest Heritage threat rank (substantial, imminent threats), and
currently with fewer than 50 individuals, or fewer than 4 populations,
originally comprised a group of approximately 40 candidate species
(``Top 40''). These 40 candidate species have had the highest priority
to receive funding to work on a proposed listing determination. As we
work on proposed and final listing rules for those 40 candidates, we
apply the ranking criteria to the next group of candidates with an LPN
of 2 and 3 to determine the next set of highest priority candidate
species. Finally, proposed rules for reclassification of threatened
species to endangered are lower priority, since as listed species, they
are already afforded the protection of the Act and implementing
regulations. However, for efficiency reasons, we may choose to work on
a proposed rule to reclassify a species to endangered if we can combine
this with work that is subject to a court-determined deadline.
With our workload so much bigger than the amount of funds we have
to accomplish it, it is important that we be as efficient as possible
in our listing process. Therefore, as we work on proposed rules for the
highest priority species in the next several years, we are preparing
multi-species proposals when appropriate, and these may include species
with lower priority if they overlap geographically or have the same
threats as a species with an LPN of 2. In addition, we take into
consideration the availability of staff resources when we determine
which high-priority species will receive funding to minimize the amount
of time and resources required to complete each listing action.
We assigned wolverines in the contiguous United States an LPN of 6,
based on our finding that the DPS faces nonimminent but high-magnitude
threats from the primary threat of the present or threatened
destruction, modification, or curtailment of its habitat from climate
change; and the secondary threats associated with Factors B, D, and E.
These threats are expected to affect wolverine populations in the
future. Under our 1983 Guidelines, a ``species'' facing nonimminent
high-magnitude threats is assigned an LPN of 4, 5, or 6, depending on
its taxonomic status. Work on a proposed listing determination for
wolverines in the contiguous United States is precluded by work on
higher priority candidate species (i.e., species with LPN of 5 or
less); listing actions with absolute statutory, court-ordered, or
court-approved deadlines; and final listing determinations for those
species that were proposed for listing with funds from previous FYs.
This work includes all the actions listed in the tables below under
expeditious progress.
As explained above, a determination that listing is warranted but
precluded must also demonstrate that expeditious progress is being made
to add and remove qualified species to and from the Lists of Endangered
and Threatened Wildlife and Plants. As with our ``precluded'' finding,
the evaluation of whether progress in adding qualified species to the
Lists has been expeditious is a function of the resources available for
listing and the competing demands for those funds. (Although we do not
discuss it in detail here, we are also making expeditious progress in
removing species from the list under the Recovery program in light of
the resource available for delisting, which is funded by a separate
line item in the budget of the Endangered Species Program. During FY
2010, we have completed two proposed delisting rules and two final
delisting rules.) Given the limited resources available for listing, we
find that we made expeditious progress in FY 2010 in the Listing
Program and are making expeditious progress in FY 2011. This progress
included preparing and publishing the determinations presented in Table
3.
Table 3--FY 2010 and FY 2011 Completed Listing Actions
----------------------------------------------------------------------------------------------------------------
Publication date Title Actions FR Pages
----------------------------------------------------------------------------------------------------------------
10/08/2009.......................... Listing Lepidium Final Listing, 74 FR 52013-52064
papilliferum (Slickspot Threatened.
Peppergrass) as a
Threatened Species
Throughout Its Range.
10/27/2009.......................... 90[dash]day Finding on a Notice of 90-day 74 FR 55177-55180
Petition To List the Petition Finding, Not
American Dipper in the Substantial.
Black Hills of South Dakota
as Threatened or Endangered.
10/28/2009.......................... Status Review of Arctic Notice of Intent to 74 FR 55524-55525
Grayling (Thymallus Conduct Status Review.
arcticus) in the Upper
Missouri River System.
[[Page 78057]]
11/03/2009.......................... Listing the British Columbia Proposed Listing 74 FR 56757-56770
Distinct Population Segment Threatened.
of the Queen Charlotte
Goshawk Under the Act:
Proposed rule.
11/03/2009.......................... Listing the Salmon-Crested Proposed Listing 74 FR 56770-56791
Cockatoo as Threatened Threatened.
Throughout Its Range with
Special Rule.
11/23/2009.......................... Status Review of Gunnison Notice of Intent to 74 FR 61100-61102
sage-grouse (Centrocercus Conduct Status Review.
minimus).
12/03/2009.......................... 12-Month Finding on a Notice of 12-month 74 FR 63343-63366
Petition to List the Black- Petition Finding, Not
tailed Prairie Dog as warranted.
Threatened or Endangered.
12/03/2009.......................... 90-Day Finding on a Petition Notice of 90-day 74 FR 63337-63343
to List Sprague's Pipit as Petition Finding,
Threatened or Endangered. Substantial.
12/15/2009.......................... 90-Day Finding on Petitions Notice of 90-day 74 FR 66260-66271
To List 9 Species of Petition Finding,
Mussels From Texas as Substantial.
Threatened or Endangered
With Critical Habitat.
12/16/2009.......................... Partial 90-Day Finding on a Notice of 90-day 74 FR 66865-66905
Petition to List 475 Petition Finding, Not
Species in the Southwestern Substantial &
United States as Threatened Subtantial.
or Endangered With Critical
Habitat.
12/17/2009.......................... 12-month Finding on a Notice of 12-month 74 FR 66937-66950
Petition To Change the Petition Finding,
Final Listing of the Warranted but
Distinct Population Segment Precluded.
of the Canada Lynx To
Include New Mexico.
01/05/2010.......................... Listing Foreign Bird Species Proposed Listing, 75 FR 605-649
in Peru & Bolivia as Endangered.
Endangered Throughout Their
Range.
01/05/2010.......................... Listing Six Foreign Birds as Proposed Listing, 75 FR 286-310
Endangered Throughout Their Endangered.
Range.
01/05/2010.......................... Withdrawal of Proposed Rule Proposed rule, 75 FR 310-316
to List Cook's Petrel. Withdrawal.
01/05/2010.......................... Final Rule to List the Final Listing, 75 FR 235-250
Galapagos Petrel & Threatened.
Heinroth's Shearwater as
Threatened Throughout Their
Ranges.
01/20/2010.......................... Initiation of Status Review Notice of Intent to 75 FR 3190-3191
for Agave eggersiana & Conduct Status Review.
Solanum conocarpum.
02/09/2010.......................... 12-month Finding on a Notice of 12-month 75 FR 6437-6471
Petition to List the Petition Finding, Not
American Pika as Threatened Warranted.
or Endangered.
02/25/2010.......................... 12-Month Finding on a Notice of 12-month 75 FR 8601-8621
Petition To List the Petition Finding, Not
Sonoran Desert Population Warranted.
of the Bald Eagle as a
Threatened or Endangered
Distinct Population Segment.
02/25/2010.......................... Withdrawal of Proposed Rule Withdrawal of Proposed 75 FR 8621-8644
To List the Southwestern Rule to List.
Washington/Columbia River
Distinct Population Segment
of Coastal Cutthroat Trout
(Oncorhynchus clarki
clarki) as Threatened.
03/18/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 13068-13071
to List the Berry Cave Petition Finding,
salamander as Endangered. Substantial.
03/23/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 13717-13720
to List the Southern Petition Finding, Not
Hickorynut Mussel (Obovaria Substantial.
jacksoniana) as Endangered
or Threatened.
03/23/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 13720-13726
to List the Striped Newt as Petition Finding,
Threatened. Substantial.
03/23/2010.......................... 12-Month Findings for Notice of 12-month 75 FR 13910-14014
Petitions to List the Petition Finding,
Greater Sage-Grouse Warranted but
(Centrocercus urophasianus) Precluded.
as Threatened or Endangered.
03/31/2010.......................... 12-Month Finding on a Notice of 12-month 75 FR 16050-16065
Petition to List the Tucson Petition Finding,
Shovel-Nosed Snake Warranted but
(Chionactis occipitalis Precluded.
klauberi) as Threatened or
Endangered with Critical
Habitat.
04/05/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 17062-17070
To List Thorne's Hairstreak Petition Finding,
Butterfly as or Endangered. Substantial.
04/06/2010.......................... 12-month Finding on a Notice of 12-month 75 FR 17352-17363
Petition To List the Petition Finding, Not
Mountain Whitefish in the Warranted.
Big Lost River, Idaho, as
Endangered or Threatened.
04/06/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 17363-17367
to List a Stonefly Petition Finding, Not
(Isoperla jewetti) & a Substantial.
Mayfly (Fallceon eatoni) as
Threatened or Endangered
with Critical Habitat.
04/07/2010.......................... 12-Month Finding on a Notice of 12-month 75 FR 17667-17680
Petition to Reclassify the Petition Finding,
Delta Smelt From Threatened Warranted but
to Endangered Throughout Precluded.
Its Range.
04/13/2010.......................... Determination of Endangered Final Listing, 75 FR 18959-19165
Status for 48 Species on Endangered.
Kauai & Designation of
Critical Habitat.
04/15/2010.......................... Initiation of Status Review Notice of Initiation of 75 FR 19591-19592
of the North American Status Review.
Wolverine in the Contiguous
United States.
04/15/2010.......................... 12-Month Finding on a Notice of 12-month 75 FR 19592-19607
Petition to List the Petition Finding, Not
Wyoming Pocket Gopher as Warranted.
Endangered or Threatened
with Critical Habitat.
[[Page 78058]]
04/16/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 19925-19935
to List a Distinct Petition Finding,
Population Segment of the Substantial.
Fisher in Its United States
Northern Rocky Mountain
Range as Endangered or
Threatened with Critical
Habitat.
04/20/2010.......................... Initiation of Status Review Notice of Initiation of 75 FR 20547-20548
for Sacramento splittail Status Review.
(Pogonichthys
macrolepidotus).
04/26/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 21568-21571
to List the Harlequin Petition Finding,
Butterfly as Endangered. Substantial.
04/27/2010.......................... 12-Month Finding on a Notice of 12-month 75 FR 22012-22025
Petition to List Susan's Petition Finding, Not
Purse-making Caddisfly Warranted.
(Ochrotrichia susanae) as
Threatened or Endangered.
04/27/2010.......................... 90-day Finding on a Petition Notice of 90-day 75 FR 22063-22070
to List the Mohave Ground Petition Finding,
Squirrel as Endangered with Substantial.
Critical Habitat.
05/04/2010.......................... 90-Day Finding on a Petition Notice of 90-day 75 FR 23654-23663
to List Hermes Copper Petition Finding,
Butterfly as Threatened or Substantial.
Endangered.
6/1/2010............................ 90-Day Finding on a Petition Notice of 90-day 75 FR 30313-30318
To List Castanea pumila Petition Finding,
var. ozarkensis. Substantial.
6/1/2010............................ 12-month Finding on a Notice of 12-month 75 FR 30338-30363
Petition to List the White- Petition Finding, Not
tailed Prairie Dog as warranted.
Endangered or Threatened.
6/9/2010............................ 90-Day Finding on a Petition Notice of 90-day 75 FR 32728-32734
To List van Rossem's Gull- Petition Finding,
billed Tern as Endangered Substantial.
or Threatened.
6/16/2010........................... 90-Day Finding on Five Notice of 90-day 75 FR 34077-34088
Petitions to List Seven Petition Finding,
Species of Hawaiian Yellow- Substantial.
faced Bees as Endangered.
6/22/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 35398-35424
Petition to List the Least Petition Finding,
Chub as Threatened or Warranted but
Endangered. precluded.
6/23/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 35746-35751
to List the Honduran Petition Finding,
Emerald Hummingbird as Substantial.
Endangered.
6/23/2010........................... Listing Ipomopsis polyantha Proposed Listing, 75 FR 35721-35746
(Pagosa Skyrocket) as Endangered; Proposed
Endangered Throughout Its Listing, Threatened.
Range, and Listing
Penstemon debilis
(Parachute Beardtongue) and
Phacelia submutica (DeBeque
Phacelia) as Threatened
Throughout Their Range.
6/24/2010........................... Listing the Flying Earwig Final Listing, 75 FR 35990-36012
Hawaiian Damselfly and Endangered.
Pacific Hawaiian Damselfly
As Endangered Throughout
Their Ranges.
6/24/2010........................... Listing the Cumberland Proposed Listing, 75 FR 36035-36057
Darter, Rush Darter, Endangered.
Yellowcheek Darter, Chucky
Madtom, and Laurel Dace as
Endangered Throughout Their
Ranges.
6/29/2010........................... Listing the Mountain Plover Reinstatement of 75 FR 37353-37358
as Threatened. Proposed Listing,
Threatened.
7/20/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 42033-42040
to List Pinus albicaulis Petition Finding,
(Whitebark Pine) as Substantial.
Endangered or Threatened
with Critical Habitat.
7/20/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 42040-42054
Petition to List the Petition Finding, Not
Amargosa Toad as Threatened warranted.
or Endangered.
7/20/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 42059-42066
to List the Giant Palouse Petition Finding,
Earthworm (Driloleirus Substantial.
americanus) as Threatened
or Endangered.
7/27/2010........................... Determination on Listing the Final Listing, 75 FR 43844-43853
Black-Breasted Puffleg as Endangered.
Endangered Throughout its
Range; Final Rule.
7/27/2010........................... Final Rule to List the Final Listing, 75 FR 43853-43864
Medium Tree-Finch Endangered.
(Camarhynchus pauper) as
Endangered Throughout Its
Range.
8/3/2010............................ Determination of Threatened Final Listing, 75 FR 45497-45527
Status for Five Penguin Threatened.
Species.
8/4/2010............................ 90-Day Finding on a Petition Notice of 90-day 75 FR 46894-46898
To List the Mexican Gray Petition Finding,
Wolf as an Endangered Substantial.
Subspecies With Critical
Habitat.
8/10/2010........................... 90[dash]Day Finding on a Notice of 90-day 75 FR 48294-48298
Petition to List Petition Finding,
Arctostaphylos franciscana Substantial.
as Endangered with Critical
Habitat.
8/17/2010........................... Listing Three Foreign Bird Final Listing, 75 FR 50813-50842
Species from Latin America Endangered.
and the Caribbean as
Endangered Throughout Their
Range.
8/17/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 50739-50742
to List Brian Head Petition Finding, Not
Mountainsnail as Endangered substantial.
or Threatened with Critical
Habitat.
8/24/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 51969-51974
to List the Oklahoma Grass Petition Finding,
Pink Orchid as Endangered Substantial.
or Threatened.
9/1/2010............................ 12-Month Finding on a Notice of 12-month 75 FR 53615-53629
Petition to List the White- Petition Finding, Not
Sided Jackrabbit as warranted.
Threatened or Endangered.
9/8/2010............................ Proposed Rule To List the Proposed Listing, 75 FR 54561-54579
Ozark Hellbender Salamander Endangered.
as Endangered.
[[Page 78059]]
9/8/2010............................ Revised 12-Month Finding to Notice of 12-month 75 FR 54707-54753
List the Upper Missouri Petition Finding,
River Distinct Population Warranted but
Segment of Arctic Grayling precluded.
as Endangered or Threatened.
9/9/2010............................ 12-Month Finding on a Notice of 12-month 75 FR 54822-54845
Petition to List the Jemez Petition Finding,
Mountains Salamander Warranted but
(Plethodon neomexicanus) as precluded.
Endangered or Threatened
with Critical Habitat.
9/15/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 56028-56050
Petition to List Sprague's Petition Finding,
Pipit as Endangered or Warranted but
Threatened Throughout Its precluded.
Range.
9/22/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 57720-57734
Petition to List Agave Petition Finding,
eggersiana (no common name) Warranted but
as Endangered. precluded.
9/28/2010........................... Determination of Endangered Final Listing, 75 FR 59645-59656
Status for the African Endangered.
Penguin.
9/28/2010........................... Determination for the Notice of 12-month 75 FR 59803-59863
Gunnison Sage[dash]grouse Petition Finding,
as a Threatened or Warranted but
Endangered Species. precluded.
9/30/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 60515-60561
Petition to List the Pygmy Petition Finding, Not
Rabbit as Endangered or warranted.
Threatened.
10/6/2010........................... Endangered Status for the Proposed Listing, 75 FR 61664-61690
Altamaha Spinymussel and Endangered.
Designation of Critical
Habitat.
10/7/2010........................... 12-month Finding on a Notice of 12-month 75 FR 62070-62095
Petition to list the Petition Finding, Not
Sacramento Splittail as warranted.
Endangered or Threatened.
10/28/2010.......................... Endangered Status and Proposed Listing 75 FR 66481-66552
Designation of Critical Endangered (uplisting).
Habitat for Spikedace and
Loach Minnow.
11/2/2010........................... 90-Day Finding on a Petition Notice of 90-day 75 FR 67341-67343
to List the Bay Springs Petition Finding, Not
Salamander as Endangered. substantial.
11/2/2010........................... Determination of Endangered Final Listing, 75 FR 67511-67550
Status for the Georgia Endangered.
Pigtoe Mussel, Interrupted
Rocksnail, and Rough
Hornsnail and Designation
of Critical Habitat.
11/2/2010........................... Listing the Rayed Bean and Proposed Listing, 75 FR 67551-67583
Snuffbox as Endangered. Endangered.
11/4/2010........................... 12-Month Finding on a Notice of 12-month 75 FR 67925-67944
Petition to List Cirsium Petition Finding,
wrightii (Wright's Marsh Warranted but
Thistle) as Endangered or precluded.
Threatened.
----------------------------------------------------------------------------------------------------------------
Our expeditious progress also includes work on listing actions that
we funded in FY 2010 and FY 2011 but have not yet been completed to
date. These actions are listed below. Actions in the top section of the
table are being conducted under a deadline set by a court. Actions in
the middle section of the table are being conducted to meet statutory
timelines, that is, timelines required under the Act. Actions in the
bottom section of the table are high-priority listing actions. These
actions include work primarily on species with an LPN of 2, and, as
discussed above, selection of these species is partially based on
available staff resources, and when appropriate, include species with a
lower priority if they overlap geographically or have the same threats
as the species with the high priority. Including these species together
in the same proposed rule results in considerable savings in time and
funding, as compared to preparing separate proposed rules for each of
them in the future.
Table 4--Actions Funded in FY 2010 and FY 2011 But Not Yet Completed
------------------------------------------------------------------------
Species Action
------------------------------------------------------------------------
Actions Subject to Court
Order/Settlement Agreement:
6 Birds from Eurasia..... Final listing determination.
Flat-tailed horned lizard Final listing determination.
Mountain plover \4\...... Final listing determination.
6 Birds from Peru........ Proposed listing determination.
Sacramento splittail..... 12-month petition finding.
Pacific walrus........... 12-month petition finding.
Wolverine................ 12-month petition finding.
Solanum conocarpum....... 12-month petition finding.
Desert tortoise--Sonoran 12-month petition finding.
population.
Thorne's Hairstreak 12-month petition finding.
butterfly \3\.
Hermes copper butterfly 12-month petition finding.
\3\.
Utah prairie dog 90-day petition finding.
(uplisting).
Actions with Statutory
Deadlines:
Casey's june beetle...... Final listing determination.
Georgia pigtoe, Final listing determination.
interrupted rocksnail,
and rough hornsnail.
7 Bird species from Final listing determination.
Brazil.
Southern rockhopper Final listing determination.
penguin--Campbell
Plateau population.
5 Bird species from Final listing determination.
Colombia and Ecuador.
Queen Charlotte goshawk.. Final listing determination.
5 species southeast fish Final listing determination.
(Cumberland darter, rush
darter, yellowcheek
darter, chucky madtom,
and laurel dace).
Salmon crested cockatoo.. Proposed listing determination.
[[Page 78060]]
CA golden trout.......... 12-month petition finding.
Black-footed albatross... 12-month petition finding.
Mount Charleston blue 12-month petition finding.
butterfly.
Mojave fringe-toed lizard 12-month petition finding.
\1\.
Kokanee--Lake Sammamish 12-month petition finding.
population \1\.
Cactus ferruginous pygmy- 12-month petition finding.
owl \1\.
Northern leopard frog.... 12-month petition finding.
Tehachapi slender 12-month petition finding.
salamander.
Coqui Llanero............ 12-month petition finding.
Dusky tree vole.......... 12-month petition finding.
3 MT invertebrates (mist 12-month petition finding.
forestfly (Lednia
tumana), Oreohelix sp.3,
Oreohelix sp. 31) from
206 species petition.
5 UT plants (Astragalus 12-month petition finding.
hamiltonii, Eriogonum
soredium, Lepidium
ostleri, Penstemon
flowersii, Trifolium
friscanum) from 206
species petition.
2 CO plants (Astragalus 12-month petition finding.
microcymbus, Astragalus
schmolliae) from 206
species petition.
5 WY plants (Abronia 12-month petition finding.
ammophila, Agrostis
rossiae, Astragalus
proimanthus, Boechere
(Arabis) pusilla,
Penstemon gibbensii)
from 206 species
petition.
Leatherside chub (from 12-month petition finding.
206 species petition).
Frigid ambersnail (from 12-month petition finding.
206 species petition).
Gopher tortoise--eastern 12-month petition finding.
population.
Wrights marsh thistle.... 12-month petition finding.
67 of 475 southwest 12-month petition finding.
species.
Grand Canyon scorpion 12-month petition finding.
(from 475 species
petition).
Anacroneuria wipukupa (a 12-month petition finding.
stonefly from 475
species petition).
Rattlesnake-master borer 12-month petition finding.
moth (from 475 species
petition).
3 Texas moths (Ursia 12-month petition finding.
furtiva, Sphingicampa
blanchardi, Agapema
galbina) (from 475
species petition).
2 Texas shiners 12-month petition finding.
(Cyprinella sp.,
Cyprinella lepida) (from
475 species petition).
3 South Arizona plants 12-month petition finding.
(Erigeron piscaticus,
Astragalus hypoxylus,
Amoreuxia gonzalezii)
(from 475 species
petition).
5 Central Texas mussel 12-month petition finding.
species (3 from 475
species petition).
14 parrots (foreign 12-month petition finding.
species).
Berry Cave salamander \1\ 12-month petition finding.
Striped Newt \1\......... 12-month petition finding.
Fisher--Northern Rocky 12-month petition finding.
Mountain Range \1\.
Mohave Ground Squirrel 12-month petition finding.
\1\.
Puerto Rico Harlequin 12-month petition finding.
Butterfly.
Western gull-billed tern. 12-month petition finding.
Ozark chinquapin 12-month petition finding.
(Castanea pumila var.
ozarkensis).
HI yellow-faced bees..... 12-month petition finding.
Giant Palouse earthworm.. 12-month petition finding.
Whitebark pine........... 12-month petition finding.
OK grass pink (Calopogon 12-month petition finding.
oklahomensis) \1\.
Southeastern pop snowy 90-day petition finding.
plover & wintering pop.
of piping plover \1\.
Eagle Lake trout \1\..... 90-day petition finding.
Smooth-billed ani \1\.... 90-day petition finding.
Bay Springs salamander 90-day petition finding.
\1\.
32 species of snails and 90-day petition finding.
slugs \1\.
42 snail species (Nevada 90-day petition finding.
& Utah).
Red knot roselaari 90-day petition finding.
subspecies.
Peary caribou............ 90-day petition finding.
Plains bison............. 90-day petition finding.
Spring Mountains 90-day petition finding.
checkerspot butterfly.
Spring pygmy sunfish..... 90-day petition finding.
Bay skipper.............. 90-day petition finding.
Unsilvered fritillary.... 90-day petition finding.
Texas kangaroo rat....... 90-day petition finding.
Spot-tailed earless 90-day petition finding.
lizard.
Eastern small-footed bat. 90-day petition finding.
Northern long-eared bat.. 90-day petition finding.
Prairie chub............. 90-day petition finding.
10 species of Great Basin 90-day petition finding.
butterfly.
6 sand dune (scarab) 90-day petition finding.
beetles.
Golden-winged warbler.... 90-day petition finding.
Sand-verbena moth........ 90-day petition finding.
404 Southeast species.... 90-day petition finding.
Franklin's bumble bee \4\ 90-day petition finding.
2 Idaho snowflies 90-day petition finding.
(straight snowfly &
Idaho snowfly) \4\.
American eel \4\......... 90-day petition finding.
Gila monster (Utah 90-day petition finding.
population) \4\.
Arapahoe snowfly \4\..... 90-day petition finding.
Leona's little blue \4\.. 90-day petition finding.
Aztec gilia \5\.......... 90-day petition finding.
[[Page 78061]]
White-tailed ptarmigan 90-day petition finding.
\5\.
San Bernardino flying 90-day petition finding.
squirrel \5\.
Bicknell's thrush \5\.... 90-day petition finding.
Coleman's coral-root 90-day petition finding.
(Hexalectris colemanii)
\5\.
Sonoran talussnail \5\... 90-day petition finding.
2 AZ Sky Island plants 90-day petition finding.
(Graptopetalum bartrami
& Pectis imberbis) \5\.
I'iwi \5\................ 90-day petition finding.
High-Priority Listing Actions
\3\:
19 Oahu candidate species Proposed listing.
\2\ (16 plants, 3
damselflies) (15 with
LPN = 2, 3 with LPN = 3,
1 with LPN = 9).
19 Maui-Nui candidate Proposed listing.
species \2\ (16 plants,
3 tree snails) (14 with
LPN = 2, 2 with LPN = 3,
3 with LPN = 8).
Dune sagebrush lizard Proposed listing.
(formerly Sand dune
lizard) \3\ (LPN = 2).
2 Arizona springsnails Proposed listing.
\2\ (Pyrgulopsis
bernadina (LPN = 2),
Pyrgulopsis trivialis
(LPN = 2)).
New Mexico springsnail Proposed listing.
\2\ (Pyrgulopsis
chupaderae (LPN = 2).
2 mussels \2\ (rayed bean Proposed listing.
(LPN = 2), snuffbox No
LPN).
2 mussels \2\ (sheepnose Proposed listing.
(LPN = 2), spectaclecase
(LPN = 4)).
Altamaha spinymussel \2\ Proposed listing.
(LPN = 2).
8 southeast mussels Proposed listing.
(southern kidneyshell
(LPN = 2), round
ebonyshell (LPN = 2),
Alabama pearlshell (LPN
= 2), southern sandshell
(LPN = 5), fuzzy pigtoe
(LPN = 5), Choctaw bean
(LPN = 5), narrow pigtoe
(LPN = 5), and tapered
pigtoe (LPN = 11)).
Umtanum buckwheat (LPN = Proposed listing.
2) \4\.
Grotto sculpin (LPN = 2) Proposed listing.
\4\.
2 Arkansas mussels Proposed listing.
(Neosho mucket (LPN = 2)
& Rabbitsfoot (LPN = 9))
\4\.
Diamond darter (LPN = 2) Proposed listing.
\4\.
Gunnison sage-grouse (LPN Proposed listing.
= 2) \4\.
Miami blue (LPN = 3) \3\. Proposed listing.
4 Texas salamanders Proposed listing.
(Austin blind salamander
(LPN = 2), Salado
salamander (LPN = 2),
Georgetown salamander
(LPN = 8), Jollyville
Plateau (LPN = 8)) \3\.
5 SW aquatics (Gonzales Proposed listing.
Spring Snail (LPN = 2),
Diamond Y springsnail
(LPN = 2), Phantom
springsnail (LPN = 2),
Phantom Cave snail (LPN
= 2), Diminutive
amphipod (LPN = 2)) \3\.
2 Texas plants (Texas Proposed listing.
golden gladecress
(Leavenworthia texana)
(LPN = 2), Neches River
rose-mallow (Hibiscus
dasycalyx) (LPN = 2))
\3\.
FL bonneted bat (LPN = 2) Proposed listing.
\3\.
Kittlitz's murrelet (LPN Proposed listing.
= 2) \5\.
Umtanum buckwheat (LPN = Proposed listing.
2) \3\.
21 Big Island (HI) Proposed listing.
species \5\ (includes 8
candidate species--5
plants & 3 animals; 4
with LPN = 2, 1 with LPN
= 3, 1 with LPN = 4, 2
with LPN = 8).
Oregon spotted frog (LPN Proposed listing.
= 2) \5\.
2 TN River mussels Proposed listing.
(fluted kidneyshell (LPN
= 2), slabside
pearlymussel (LPN = 2)
\5\.
Jemez Mountain salamander Proposed listing.
(LPN = 2) \5\.
------------------------------------------------------------------------
\1\ Funds for listing actions for these species were provided in
previous FYs.
\2\ Although funds for these high-priority listing actions were provided
in FY 2008 or 2009, due to the complexity of these actions and
competing priorities, these actions are still being developed.
\3\ Partially funded with FY 2010 funds and FY 2011 funds.
\4\ Funded with FY 2010 funds.
\5\ Funded with FY 2011 funds.
We have endeavored to make our listing actions as efficient and
timely as possible, given the requirements of the relevant law and
regulations, and constraints relating to workload and personnel. We are
continually considering ways to streamline processes or achieve
economies of scale, such as by batching related actions together. Given
our limited budget for implementing section 4 of the Act, these actions
described above collectively constitute expeditious progress.
The North American wolverine in the contiguous United States will
be added to the list of candidate species upon publication of this 12-
month finding. We will continue to evaluate this species as new
information becomes available. Continuing review will determine if a
change in status is warranted, including the need to make prompt use of
emergency listing procedures.
We intend that any proposed listing determination for the North
American wolverine in the contiguous United States will be as accurate
as possible. Therefore, we will continue to accept additional
information and comments from all concerned governmental agencies, the
scientific community, industry, or any other interested party
concerning this finding.
References Cited
A complete list of all references cited is available upon request
from the Supervisor at the U.S. Fish and Wildlife Service, Montana
Field Office (see ADDRESSES).
Author
The primary authors of this notice are the staff members of the
Montana Field Office (see ADDRESSES).
Authority
The authority for this action is section 4 of the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: November 19, 2010.
Paul R. Schmidt,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2010-30573 Filed 12-13-10; 8:45 am]
BILLING CODE 4310-55-P