[Federal Register Volume 85, Number 198 (Tuesday, October 13, 2020)]
[Proposed Rules]
[Pages 64618-64648]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-19538]



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Vol. 85

Tuesday,

No. 198

October 13, 2020

Part II





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; Withdrawal of the 
Proposed Rule for the North American Wolverine; Proposed Rule

  Federal Register / Vol. 85 , No. 198 / Tuesday, October 13, 2020 / 
Proposed Rules  

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R6-ES-2016-0106; FF09E21000 FXES11110900000 201]
RIN 1018-BB78


Endangered and Threatened Wildlife and Plants; Withdrawal of the 
Proposed Rule for the North American Wolverine

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule, withdrawal.

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SUMMARY: We, the U.S. Fish and Wildlife Service, withdraw the proposed 
rule to list the distinct population segment (DPS) of the North 
American wolverine (Gulo gulo luscus) occurring in the contiguous 
United States as a threatened species under the Endangered Species Act 
of 1973, as amended (Act). This withdrawal is based on our conclusion 
that the factors affecting the species as identified in the proposed 
rule are not as significant as believed at the time of the proposed 
rule. We base this conclusion on our analysis of current and future 
threat factors. We also find that North American wolverines occurring 
in the contiguous United States do not qualify as a DPS. Therefore, we 
are withdrawing our proposal to list the wolverine within the 
contiguous United States as a threatened species.

DATES: The proposed rule that published February 4, 2013 (78 FR 7864), 
to list the distinct population segment of the North American wolverine 
occurring in the contiguous United States as a threatened species is 
withdrawn on October 13, 2020.

ADDRESSES: The withdrawal of our proposed rule, comments, and 
supplementary documents are available on the internet at http://www.regulations.gov at Docket Nos. FWS-R6-ES-2012-0107 and FWS-R6-ES-
2016-0106.

FOR FURTHER INFORMATION CONTACT: Jodi Bush, Field Supervisor, U.S. Fish 
and Wildlife Service, Montana Ecological Services Office, (see 
ADDRESSES). Persons who use a telecommunications device for the deaf 
may call the Federal Relay Service at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act, if we determine that 
a species may be an endangered or threatened species throughout all or 
a significant portion of its range, we are required to promptly publish 
a proposal in the Federal Register and make a determination on our 
proposal within 1 year. To the maximum extent prudent and determinable, 
we must designate critical habitat for any species that we determine to 
be an endangered or threatened species under the Act. Listing a species 
as an endangered or threatened species and designation of critical 
habitat can only be completed by issuing a rule.
    What this document does. We withdraw the proposed rule to list the 
DPS of the North American wolverine occurring in the contiguous United 
States as a threatened species under the Act.
    The basis for our action. Under the Act, we may determine that a 
species is an endangered or threatened species because of any of 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. We have determined that the factors affecting the 
species as identified in the proposed rule (loss of habitat due to 
climate change) are not as significant as believed at the time of the 
proposed rule. We also find that North American wolverines occurring in 
the contiguous United States do not qualify as a DPS.
    Peer review. In accordance with our July 1, 1994, peer review 
policy (59 FR 34270; July 1, 1994), the Service's August 22, 2016, 
Director's Memo on the Peer Review Process, and the Office of 
Management and Budget's December 16, 2004, Final Information Quality 
Bulletin for Peer Review (revised June 2012), we sought the expert 
opinions of four appropriate specialists regarding the species status 
assessment report. We received responses from four specialists, which 
informed this proposed rule. The purpose of peer review is to ensure 
that our listing determinations are based on scientifically sound data, 
assumptions, and analyses. The peer reviewers have expertise in the 
biology, habitat, and threats to the species. Results of this 
structured peer review process can be found at https://www.fws.gov/mountain-prairie/science/peerReview.php. A draft analysis was also 
submitted to our Federal, State, and Tribal partners for scientific 
review. In preparing this withdrawal, we incorporated the results of 
these reviews in the final SSA report, as appropriate.
    During the reopening of the public comment periods for the proposed 
listing rule, we requested any new information and announced that we 
initiated a new and comprehensive status review of the North American 
wolverine to determine whether the species meets the definition of an 
endangered or threatened species under the Act, or whether the species 
is not warranted for listing. The wolverine SSA report provides the 
scientific basis for the decision to withdraw the proposed listing rule 
for the DPS of wolverine occurring in the contiguous United States. 
Both new and updated information and analyses presented in the 
wolverine SSA report, summarized below in support of our listing 
determination, along with public comment, have also prompted us to 
reevaluate our previous assessment of the DPS with respect to wolverine 
in the contiguous United States.

Supporting Documents

    A team prepared a Species Status Assessment (SSA) for the North 
American Wolverine (Gulo gulo luscus) (Service, 2018) (hereafter 
referred to as the wolverine SSA report). The SSA team was composed of 
U.S. Fish and Wildlife Service biologists, who consulted with other 
species experts. The wolverine SSA report represents a compilation of 
the best scientific and commercial data available concerning the status 
of the species, including the impacts of past, present, and future 
factors (both negative and beneficial) affecting the wolverine. The 
wolverine SSA report underwent independent peer review by scientists 
with experience with mesocarnivores and their conservation and 
management, genetics, population modeling, and climate change. The 
wolverine SSA report and other materials relating to this proposal can 
be found on the Mountain-Prairie Region website at https://www.fws.gov/mountain-prairie/ and at http://www.regulations.gov under Docket No. 
FWS-R6-ES-2016-0106.

Previous Federal Actions

    Please refer to the proposed listing rule for the wolverine (78 FR 
7864; February 4, 2013) for a detailed description of previous Federal 
actions concerning the wolverine prior to 2013. On February 4, 2013, we 
published a proposed rule to list the DPS of wolverine occurring in the 
contiguous United States as threatened, under the Act, with a proposed 
rule under section 4(d) of the Act that outlines the prohibitions 
necessary and advisable for the conservation of the wolverine (78 FR

[[Page 64619]]

7864). We also published a proposed rule on February 4, 2013, to 
establish a nonessential experimental population (NEP) area for the 
North American wolverine in the Southern Rocky Mountains of Colorado, 
northern New Mexico, and southern Wyoming (78 FR 7890). On October 31, 
2013, we reopened the comment period on the proposed listing rule for 
an additional 30 days (78 FR 65248).
    Following publication of the 2013 proposed rules, there was 
scientific disagreement and debate about the interpretation of the 
habitat requirements for wolverines and the available climate change 
information used to determine the extent of threats to the DPS. Based 
on this substantial disagreement regarding the sufficiency or accuracy 
of the available data relevant to the proposed listing, on February 5, 
2014 (79 FR 6874), we announced a 6-month extension of the final 
determination of whether to list the wolverine DPS as a threatened 
species. We also reopened the comment period on the proposed rule to 
list the contiguous United States DPS of the North American wolverine 
for 90 days.
    On August 13, 2014, we withdrew the proposed rule to list the DPS 
of the North American wolverine as a threatened species under the Act 
(79 FR 47522). This withdrawal was based on our conclusion that the 
factors affecting the DPS as identified in the proposed rule were not 
as significant as believed at the time of the proposed rule's 
publication in 2013. As a result, we also withdrew our associated 
proposed rule under section 4(d) of the Act contained in the proposed 
listing rule and withdrew the proposed NEP designation under section 
10(j) of the Act for the southern Rocky Mountains.
    In October 2014, three complaints were filed in the District Court 
for the District of Montana by Defenders of Wildlife, WildEarth 
Guardians, Center for Biological Diversity, and other organizations 
challenging the withdrawal of the proposal to list the North American 
wolverine DPS. Numerous parties intervened in the litigation. These 
three cases were consolidated, and on April 4, 2016, the court issued a 
decision. The court granted plaintiff's motion for summary judgment 
with respect to the Service's determination regarding (1) the threat 
posed to the wolverine by the effects of climate change at the 
reproductive denning scale, (2) the threat posed to the wolverine by 
small population size and lack of genetic diversity, and (3) the 
application of the significant portion of its range policy to the 
wolverine. As a result of the court order, the August 13, 2014, 
withdrawal (79 FR 47522) was vacated and remanded to the Service for 
further consideration consistent with the order. As documented in the 
SSA report, the Service conducted additional analyses and reviewed new 
literature regarding climate change effects at the denning scale (see 
pages 73-99 of the SSA report) and included additional life-history 
information relevant to this potential stressor (see pages 25-39). With 
regard to population size, we also provide in the SSA report an 
analysis of information on wolverine population abundance and 
distribution (to date) and have included a discussion of population 
structure (genetics, effective population size) in the context of the 
species' known genetic variability (see pages 44-50). Finally, in this 
withdrawal, we have provided an updated significant portion of its 
range analysis (see discussion below).
    In effect, the court's action returned the process to the proposed 
rule stage, and the status of the wolverine under the Act reverted to 
that of a proposed species for the purposes of consultation under 
section 7 of the Act. On October 18, 2016, we published a notice (81 FR 
71670) reopening the comment period on the February 4, 2013, proposed 
rule (78 FR 7864) to list the DPS of wolverine occurring in the 
contiguous United States as threatened, under the Act. We also 
requested new information and announced that we initiated a new and 
comprehensive status review of the North American wolverine, to 
determine whether the species meets the definition of an endangered or 
threatened species under the Act, or whether the species is not 
warranted for listing. The wolverine SSA report provides the scientific 
basis for the decision to withdraw the proposed listing rule for the 
DPS of wolverine occurring in the contiguous United States. Both new 
and updated information and analyses presented in the wolverine SSA 
report, summarized below in support of our listing determination, along 
with public comment, have prompted us to reevaluate our previous 
assessment of the DPS (presented in our 2013 proposed listing rule, 
which in turn relied on the DPS analysis completed in our 2010 12-month 
finding) with respect to wolverine in the contiguous United States.

Summary of Comments and Recommendations

    As stated above in the Previous Federal Actions section, on October 
18, 2016 (81 FR 71670), we opened a public comment period on our 
February 4, 2013, proposed rule (78 FR 7864) to list the DPS of 
wolverine occurring in the contiguous United States as threatened. We 
also contacted appropriate Federal and State agencies, scientific 
experts and organizations, Tribes, and other interested parties and 
invited them to comment on the proposed rule. Many of the comments we 
received from State agencies during our notice for reopening the 
comment period (81 FR 71670) were similar to those received for the 
previously proposed rule (78 FR 7864). All substantive information 
provided during comment periods has either been incorporated directly 
into this final determination or is addressed below.

Public Comments

    (1) Comment: We received several public comments claiming that the 
North American wolverine faces increasing threats from the effects of 
climate change, particularly habitat loss due to declining snow pack.
    Our Response: As discussed in the wolverine SSA report, we 
recognize that current climate trends and future (2055 and later) 
climate model projections indicate warming temperatures for much of 
western North America and changes to snow pack conditions. Our review 
of the literature found that, overall, higher elevation areas (e.g., 
Rocky Mountains, Sierra Nevada Mountains) are more resilient to 
projected changes in temperature and precipitation as compared to lower 
elevations (Wobus et al. 2017, p. 12). In general, models indicate 
higher elevations, where documented historical wolverine denning has 
occurred, will retain more snow cover than lower elevations, 
particularly in early spring (April 30/May 1). We present in the 
wolverine SSA report a summary of new, fine-scale analysis of future 
snow persistence in two regions of the western United States, Glacier 
National Park and Rocky Mountain National Park. The two regions studied 
include a high-latitude area near tree line within Glacier National 
Park, where tree line occurs at (~1,800 to 2,100 meters (m) (5,906 to 
6,890 feet (ft))) that is currently occupied by wolverines; and a lower 
latitude area within Rocky Mountain National Park (occupied by a single 
male wolverine from 2009 to at least 2012, but not known to be 
currently occupied), where tree line occurs at higher elevation (~3,500 
m (11,483 ft)) (Ray et al. 2017, p. 2). These sites were chosen to 
bracket the range of latitude and elevation wolverines currently occupy 
in the contiguous United States (Ray et al. 2017, p. 2). This effort 
built upon previous model projections presented in McKelvey et al. 
(2011), but with significant differences such as finer

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spatial resolution, incorporation of slope and aspect, snow depth 
estimates, additional years of historical data, and wider temporal 
analyses of snow persistence (April-June). Details of this modeling 
exercise are presented in Ray et al. (2017), and summarized in the SSA 
report. That analysis indicates significant areas (several hundred 
square kilometers (km\2\)/square miles (mi\2\) for each study area) of 
future snow (greater than 0.5 m (20 inches (in) in depth) will persist 
on May 1 at elevations currently used by wolverines for denning. This 
is true, on average, across the range of climate models used out to 
approximately year 2055.
    (2) Comment: We received several public comments during our request 
for information claiming that low population size (and small effective 
population size) warrant listing of the North American wolverine as 
threatened or endangered.
    Our Response: Small populations in and of themselves do not 
constitute a threat such that a species would be endangered or 
threatened. When evaluating species status, we take into consideration 
the species' life history, population dynamics, and other impacts to 
populations and species to determine if small population dynamics 
increases the species' vulnerability to extinction such that listing as 
threatened or endangered is warranted. Wolverines are difficult animals 
to survey, and populations occur in naturally low densities across 
their North American range due, in large part, to their need for large, 
exclusive territories. At the present time, there is no reliable 
estimate of the number of wolverines that currently occupy or 
previously occupied the contiguous United States, nor are there 
reliable quantitative estimates of wolverine population trends in the 
contiguous United States. The often-cited population estimate of 318 
wolverines (range: 249-626) in the contiguous United States is derived 
from a habitat modeling exercise presented in Inman et al. (2013). That 
publication also provided a model estimate of potential wolverine 
capacity of 644 (range: 249-626). However, both of these estimates did 
not consider important spatial considerations related to wolverine 
behavior, such as territoriality, relative to wolverine populations. 
Despite the paucity of information regarding wolverine populations, the 
SSA analysis is a thorough examination of all of the available 
population information.
    As discussed in the wolverine SSA report, preliminary field results 
from a recent (2016-2017) occupancy study in four western States 
(Idaho, Montana, Washington, and Wyoming) and from a pilot occupancy 
study in Wyoming (2015-2016) indicate detections of wolverines in areas 
where they would be expected to be found, but also no detections in 
areas where they are known to occur (e.g., areas within Glacier 
National Park) (see Service 2018, Appendix B for a descriptive map). To 
date, this study reports a total of 86 photographic detections through 
camera-trapping and 157 wolverine hair samples collected for genetic 
analysis. It has not yet been determined from the camera-trap images or 
hair samples how many of the detections are unique individuals. 
Preliminary analysis of the study results indicates an average 
estimated probability of occupancy of 0.42 suggesting that wolverines 
used nearly half of all sites during the study period (Montana FWP, 
pers. comm., 2017); however, the study did not encompass all potential 
wolverine habitat in the western United States (Service 2018, Appendix 
B). For example, wolverines have also been recently detected in 
northeastern Oregon (as of 2017) and in parts of Grand Teton National 
Park (two records during the winter of 2017), which were not included 
in the surveyed study cells. Our SSA report presents a visual summary 
of these recent detections (Service 2018, Figure 3). Although the sum 
of these reports cannot confirm previous estimates of population size 
or verify population trends, they offer recent evidence that wolverines 
continue to be observed across a large area of the western United 
States.
    The 2013 proposed rule presented an effective population size 
estimate from a publication by Schwartz et al. (2009), which estimated 
a summed effective population size of 35, with credible limits from 28 
to 52 (Schwartz et al. 2009, p. 3,226). As described in the SSA report, 
the study used wolverine samples from the main part of the Rocky 
Mountain wolverine populations and did not include subpopulations from 
two other mountain regions in Montana, and samples were missing from 
other parts of the wolverine range in Idaho and other areas of Montana. 
Thus, the analysis missed both wolverine subpopulations and 
individuals, which would underestimate the results for this type of 
analysis.
    In the wolverine SSA report, we provide a contextual discussion of 
the effective population size concept, particularly in the context of 
genetic studies related to the phylogeographic history of the North 
American wolverine that were not well described in the 2013 proposed 
rule. In sum, the spatial distribution of genetic variability currently 
observed in wolverines in North America appears to be a reflection of a 
complex history in which population abundance has fluctuated since the 
time of the last glaciation with insufficient time passing since human 
persecution since at least the 1700s to allow for full recovery of 
wolverine densities (Cardinal 2004, pp. 23-24; Zigouris et al. 2012, p. 
1,554). This history and the fact that wolverines in the contiguous 
United States occupy the southern periphery of the species' entire 
North American range are important considerations in estimating and 
interpreting current wolverine distribution and abundance. The 
wolverine SSA report also presents information from genetic and 
observational studies that provide support for wolverine movement 
across the international border of the contiguous United States and 
Canada. In the 2013 proposed rule, we stated there is an apparent lack 
of connectivity between wolverine populations in Canada and the United 
States based on genetic data (78 FR 7864; February 4, 2013). We now 
consider wolverines that occupy the contiguous United States to be 
genetically continuous with wolverines in adjacent Canadian provinces. 
A small effective population size would be more of a concern if the 
population was in isolation; however, wolverines in the contiguous 
United States are not genetically isolated from wolverines in Canada. 
For more information, see the Small Total Population Size and Effective 
Population Size sections under Distinct Population Segment below.
    (3) Comment: We received several public comments during our request 
for information claiming that North American wolverine face threats 
from indiscriminant trapping in the contiguous United States, or are 
threatened by incidental trapping.
    Our Response: At the present time, trapping or hunting of wolverine 
is not allowed in any State within the range of the wolverine (with the 
exception of Alaska). Legal protections for wolverines are codified in 
western State laws and regulations and include: Endangered in Colorado, 
threatened in California and Oregon, candidate species in Washington, 
non-game species protections in Idaho and Wyoming, a species of concern 
and a furbearer with a closed season in Montana, and protection from 
collection, importation, and possession in Utah. Since 2013, there has 
been a zero quota for trapping or harvest of wolverine in Montana.
    Incidental trapping of wolverines has been documented in the 
contiguous

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United States (as recently as December 2017), though not all events 
have resulted in mortality. In the wolverine SSA report, we provide a 
summary of the number of wolverines that have been incidentally trapped 
in Idaho (18 since 1965, including 6 known to be released alive and 7 
known mortalities), Montana (4 since 2013, 3 mortalities and 1 released 
unharmed), and Wyoming (2 since 1996, 1 mortality and 1 released 
unharmed) (Service 2018, p. 66). Both Idaho and Montana are 
implementing trapper education programs to minimize nontarget wolverine 
captures.
    As discussed in the SSA report, regulated trapping and hunting of 
wolverines occurs in parts of Alaska and Canada, and appears to be 
sustainable based on population and density estimates.
    (4) Comment: We received several public comments identifying 
potential threats to wolverines from winter recreation activities, such 
as snowmobiling and back-country skiing.
    Our Response: In the SSA report, we present a summary of winter 
recreation studies (Heinemeyer et al. 2015; Heinemeyer et al. 2017), 
future projections of winter recreation activity in the contiguous 
United States (White et al. 2014), and projections of snowpack relative 
to changes in the length of the winter recreation season (Wobus et al. 
2017). We reported results from Heinemeyer (2016, pers. comm.) 
indicating a behavioral response to recreation activities, but also 
maintenance of home ranges within some areas of relatively high 
recreation activity over several years. The study has not yet been able 
to determine whether resident wolverines are reproductively successful 
due to the limited monitoring information available for reproducing 
female wolverines. Nor was the study able to determine if recreational 
activities had a negative impact on wolverine reproductive success.
    We also note here that we received the final report of this 
multiyear study (Heinemeyer et al. 2017) in mid-December 2017 (results 
of this study were recently published (Heinemeyer et al. 2019)), which 
was after we submitted the draft SSA report for review to four peer 
reviewers and to our State, Federal, and Tribal partners. Much of the 
report presents a modeling exercise to evaluate wolverine behavior 
patterns with winter recreation activities. The study found that 
wolverines maintained multiyear home ranges, and the authors suggest 
that wolverines are able to tolerate winter recreation at some scales 
(Heinemeyer et al. 2017, p. iv; Heinemeyer et al. 2019, p. 16). The 
study described habitat selection as complex for female wolverines and 
was likely driven by a combination of abiotic (snow, cold) and biotic 
(predator avoidance, food availability) factors (Heinemeyer et al., 
2017, p. 36; Heinemeyer et al. 2019, p. 16). This study did not assess 
demographic effects, fitness effects, or population level effects of 
winter recreation on wolverines (Heinemeyer et al. 2019, p. 17 and 19). 
As discussed in the wolverine SSA report, management measures being 
implemented in areas within the wolverine's current extent of 
occurrence include road closures to minimize disturbance to wildlife on 
lands managed by the U.S. Forest Service and National Park Service 
(Service 2018, p. 61 and Appendix F). In addition, management 
strategies are identified in State Wildlife Action Plans (e.g., Oregon, 
Montana, Idaho) to address potential impacts from recreation to the 
wolverine. Although we did not rely on these conservation measures to 
support our decision, they do provide some level of protection to 
address potential impacts from disturbance from winter recreation 
activity and mortality from roads.
    (5) Comment: We received public comments claiming that wolverines 
are dependent on deep snow for survival and expressing concern for 
future changes in snow pack due to the effects of climate change.
    Our Response: After reviewing studies not previously considered and 
the results of new studies/publications made available after the 2013 
and 2014 proposed rules (e.g., Aronsson 2017, Aronsson and Persson 
2016, Aronsson et al. 2017, Magoun et al. 2017, Persson et al. 2017, 
Stewart et al. 2016, Webb et al. 2016, see complete list of citations 
in the wolverine SSA report), we present in the SSA report a detailed 
discussion of the North American wolverine's physiology and other life-
history characteristics (e.g., reproductive behavior). This summary 
speaks to several presumed aspects of the relationship of denning 
behavior and other needs of this species regarding the presence of 
persistent spring snow. As summarized below, we now know that 
wolverines can and have denned outside of heavy snowpack, multiple 
factors play a role in den site selection, females will move dens as 
young become mobile, and areas of significant snowpack will likely 
persist in the future in areas where wolverines are known to den at 
levels that will continue to support wolverines.
    Denning habitat for the wolverine varies over its range and is 
dependent on local and regional environmental conditions (e.g., 
topographic and other structural features) and biotic (e.g., 
availability of prey; protection from predators) factors. Reproductive 
(natal) dens are not always excavated in deep snow, particularly in 
boreal forest habitats (Dawson et al. 2010; Novikov 1962; Webb et al. 
2016; Jokinen 2019.), and have been observed in spruce tree root balls, 
logging slash piles, and beaver dens/dams. In the contiguous United 
States, dens are found at high elevations, often in talus slopes, which 
provides conditions for protection and food caching (e.g., restricted 
access and cold temperatures). Our review of studies of wolverine 
denning activity found no quantitative data reporting snow depth at the 
den site when wolverines abandon the den. More importantly, wolverine 
reproductive success has not been studied relative to a number of 
abiotic and biotic conditions, including depth and temporal aspect of 
spring snow cover.
    Wolverines begin shifting den locations in late April, when young 
become more mobile and reliant on solid food brought to them by the 
mother (Aronsson 2017, p. 46; Aubry et al. 2016, p. 24). The 
bioclimatic model presented in Copeland et al. (2010) was used to test 
wolverine distribution at a broad scale based on climate variables, 
including spring snow cover, using May 15 conditions. They then tested 
their hypothesis by comparing and correlating the location of wolverine 
dens across their circumboreal range, and telemetry locations from 
wolverine studies in North America and Scandinavia (Copeland et al. 
2010, p. 234). Since that publication, wolverines and wolverine dens 
have been observed outside the boundaries defined by the model 
presented in Copeland et al. (2010) (e.g., Webb et al. 2016, Webb 2017 
pers. comm., Persson 2017, pers. comm.). While these observations are 
found at higher latitudes in the circumboreal region, they also 
indicate wolverines and wolverine dens are observed in environments 
that are not characterized by several feet of spring snow on May 15. In 
sum, Copeland et al. (2010) provided a fairly accurate assessment of 
where wolverine populations are expected to occur, but it did not 
evaluate (model) snow persistence at the den site scale based on 
location and denning period.
    In the SSA report, we present an analysis of 34 wolverine den 
locations (years 2002-2015) from studies in the western contiguous 
United States relative to ``melt out'' dates, which represents the 
first day of an 8-day satellite (Moderate Resolution Imaging

[[Page 64622]]

Spectroradiometer (MODIS)) composite of when the den switches from 
``snow'' to ``no snow'' at a 500-by-500-m (1,640-by-1,640-ft) spatial 
resolution. For natal den locations, the range of the melt-out dates 
was from May 25 to June 12, which is considerably later than the May 15 
date used in the Copeland et al. (2010) analysis. The estimated melt-
out dates indicate that snow is persistent at these locations past the 
time when young wolverines are generally moving out of natal dens 
(i.e., late April).
    The Copeland et al. (2010) snow model was then used by McKelvey et 
al. (2011) to model effects of climate change to wolverine habitat in 
the western United States to develop projections of habitat loss. This 
modeling exercise used May 1 snow presence as a proxy for May 15 snow 
disappearance and a spatial resolution of 36.3 km\2\ (14 mi\2\)), which 
is not relevant at the at the den site scale. As described in our 
Response to Comment #1, in the SSA report, we presented a finer scale 
analysis (0.0625 km\2\ (0.24 mi\2\)) for two study areas (Glacier 
National Park and Rocky Mountain National Park) that focused directly 
on May 15, in addition to the presence or absence of snow on May 1 and 
April 15 in our evaluation of the effects of climate change to 
snowpack. These dates are more relevant to wolverine life-history 
needs. We also modeled the depth of ``significant'' snow (0.5 m (1.64 
ft)) on these dates. We found that large areas (several hundred km\2\/
mi\2\ for each study area) of future snow (greater than 0.5 m (20 in) 
in depth) are projected to persist on May 1 at elevations currently 
used by wolverines for denning. This is true, on average, across the 
range of climate models used out to approximately year 2055. We 
recognize that wolverines are difficult to study and evaluation of 
denning habitat and behavior is challenging. Additional research is 
needed to evaluate other potential physical and biotic variables that 
could be important in defining wolverine distribution and den 
locations. These additional variables include: prey availability, risk 
of predation, den-site scale factors such as structure/snow conditions, 
and temporal use of dens.
    (6) Comment: We received public comments identifying the need for 
additional research and recommendations for conservation measures for 
the North American wolverine, including estimates of population size 
and further evaluation of life-history characteristics, and 
recommendations for conservation measures.
    Our Response: We appreciate the comments acknowledging the need for 
additional studies as well as the difficulties in studying wolverines 
given its occupation of remote habitats in the contiguous United 
States. In the wolverine SSA report, we provide a summary of the 
preliminary field and genetic results from the recent Western States 
Wolverine Conservation Project (WSWCP)-Coordinated Occupancy Study in 
four western (contiguous United) States, as well as results from 
several new studies presented in peer-reviewed publications and in 
other reports from Canada and Scandinavia. As discussed in the SSA 
report, the Western States Wolverine Working Group is continuing to 
develop studies to evaluate wolverine population distribution and 
occupancy, and connectivity across four western States.
    (7) Comment: We received additional comments from the public 
including the need for collaboration with local government and 
community stakeholders and use of best available science in developing 
the proposed rule.
    Our Response: During our preparation of the wolverine SSA report, 
we coordinated extensively with many wolverine researchers in the 
United States (including Alaska), Canada, and Scandinavia. Those 
communications are identified in our References Cited section of the 
wolverine SSA report. Their expertise, insights, and published or soon-
to-be published research papers were invaluable in ensuring that we 
used the best available science in preparing the new status review. We 
also communicated with biologists at several State and Federal agencies 
to ensure that we had incorporated the most recent wolverine detections 
in the western United States. The wolverine SSA report was sent to four 
independent peer reviewers, selected by an outside contractor, and 
those non-attributable comments were incorporated, to the extent 
possible, in the final document. We also reviewed comments received 
from the public and previous peer reviewers during our request for 
comments for our previous proposed rule and considered the information 
provided (78 FR 7864; February 4, 2013) during the preparation of the 
wolverine SSA report. As a result, this determination is based upon the 
best scientific and commercial data available to us, as required by the 
Act.
    (8) Comment: We also received public comments recommending that the 
North American wolverine not be listed as threatened or endangered 
under the Act. One commenter stated that State wildlife agencies are 
capable of managing the species and are able to provide protections 
that ensure continued population growth towards population objectives 
established by these agencies and that mandates of various Federal 
resource management agencies provide a commitment to managing wildlife 
habitat in a way that benefits all wildlife species, including 
wolverines and other forest carnivores.
    Our Response: We acknowledge that some members of the public 
support our decision to withdraw our proposed rule to list the North 
American wolverine as threatened under the Act. In the wolverine SSA 
report (Service 2018, Appendix G), we provide a summary of the 
regulatory protections provided by western States and Federal agencies 
as well as management measures being implemented to conserve the 
wolverine and its habitat. Legal protections in the contiguous United 
States include State listing in California and Oregon (threatened), 
endangered in Colorado, a candidate species in Washington, non-game 
species protections in Idaho and Wyoming, a species of concern and 
furbearer with a closed season in Montana, and protection from 
collection, importation, and possession in Utah. Trapping or hunting of 
wolverines is currently prohibited in the contiguous United States.
    (9) Comment: In response to our request for information in our 
public notice, several members of the public provided specific 
information related to personal wolverine sightings of the North 
American wolverine in the contiguous United States (e.g., New Mexico, 
Wyoming), and information regarding past and ongoing research studies 
of the species in the western United States and in Canada.
    Our Response: We appreciate the personal observations provided and 
encourage members of the public to document sightings of the North 
American wolverine with photographs and provide additional details to 
State wildlife agencies. Information we received regarding results from 
research studies has been incorporated, as appropriate, in the final 
wolverine SSA report.
    (10) Comment: We received comments from several organizations that 
support the listing of the North American wolverine and designation of 
critical habitat. Threats cited include concerns related to migration, 
habitat loss and connectivity related to threats from effects of 
climate change, nontarget trapping pressures, road mortality and other 
effects of roads (e.g., noise, pollution, fragmentation of habitat), 
motorized recreation and traffic in wildlife corridors, timber sales 
and

[[Page 64623]]

associated roads, and effects of snowmobile traffic (habitat 
fragmentation and pollution, and change in behavior).
    Our Response: As discussed in the Risk Factors for the North 
American Wolverine section below, we identified several potential 
stressors that may be affecting the species and its habitat currently 
or in the future, including impacts associated with climate change 
effects. We recognize there is limited information available for the 
wolverine, including population estimates and abundance trends. Based 
on the best available information, demographic risks to the species 
from either known or most likely potential stressors (i.e., disturbance 
due to winter recreational activities, other human disturbances, 
effects of wildland fire, disease, predation, overutilization, genetic 
diversity, small population effects, climate change, and cumulative 
effects) are low based on our evaluation of the best available 
information as it applies to current and potential future conditions 
for the wolverine and in the context of the attributes that affect the 
needs of the species (Service 2018, p. 103). Thus, we determined that, 
based on the best available information, the North American wolverine 
in the contiguous United States does not meet the definition of a 
threatened species or an endangered species under the Act.
    (11) Comment: We received public comments stating that protection 
of North American wolverines in the contiguous United States is needed 
under the Act in order to provide resources and attention needed for 
research and monitoring, to better understand threats, and sustain 
wolverines into the future. The commenter also stated that federally 
sponsored wolverine reintroduction in Colorado will help increase 
chances of long-term species survival.
    Our Response: We appreciate the recognition of the need for 
continued resources for research and monitoring. However, we base our 
listing decisions on a determination of whether the species meets the 
Act's definitions of a threatened species or an endangered species. 
Regardless, as summarized in the SSA report, in 2015, State wildlife 
agencies in Idaho, Montana, Washington, and Wyoming, along with 
Federal, tribal, and nongovernmental organization partners, developed a 
collaborative and coordinated monitoring program to be implemented in a 
coordinated fashion across the species' range in the western United 
States. In 2015, the State of Wyoming contracted with the Wolverine 
Initiative to conduct the Wyoming Wolverine Occupancy Pilot Study to 
address questions pertaining to the status and distribution of 
wolverines throughout the Greater Yellowstone Ecosystem and the Bighorn 
Mountains in the winter of 2015-2016. Expanding on this study, the 
Western States Wolverine Working Group designed and implemented the 
WSWCP-Coordinated Occupancy Survey in the winter of 2016-2017, and 
preliminary results are presented in the SSA report. The Western 
Association of Fish and Wildlife Agencies (WAFWA) Wildlife Chiefs 
Wolverine Subcommittee (formally endorsed in 2014) currently provides a 
forum for western States to work collaboratively with each other and 
with the Service, Tribes, and other partners, for conserving wolverines 
across the western United States. To date, approximately $1.5 million 
of that funding has been applied towards conservation and management 
actions, including the WSWCP (McDonald 2017, pers. comm.). This group 
is also developing a connectivity study project to support conservation 
planning efforts for the Rocky Mountains and North Cascades regions.
    In addition, multiple western States have identified the North 
American wolverine as a Species of Greatest Conservation Need in their 
State Wildlife Action Plans, and the North American wolverine is a 
focal species of conservation strategies for conservation targets in a 
number of ecoregions (e.g., Cascades, Sierra Nevada) that support 
forested lowlands, subalpine-high montane conifer forest where 
wolverines occur. These State designations provide information to 
assist resource managers with proactive decision making regarding 
species conservation and data collection priorities. Finally, the Nez 
Perce Tribe is currently preparing an Integrated Resource Management 
Plan, a Plant and Wildlife Conservation Strategy, and a Forest 
Management plan with the wolverine defined as a species of conservation 
concern in all three draft plans (Miles 2017, pers. comm.).
    In total, these funded and volunteer collaborative, landscape-level 
conservation efforts ensure continued support for the conservation of 
the North American wolverine. Although we did not rely on these plans 
to support our decision, we recognize that these plans, when 
implemented, will likely benefit wolverines and their habitat.
    (12) Comment: We received comments from several industry groups 
supporting our August 13, 2014, withdrawal (79 FR 47522) of our 
February 4, 2013, proposed rule (78 FR 7864) to list the North American 
wolverine as threatened. In general, their support rests on the 
following: (1) The DPS determination presented in our previous proposed 
rules (both 2010 and 2013) was flawed; (2) the North American wolverine 
does not meet the definition of a threatened species; (3) the obligate 
relationship with denning and need for snow has not been adequately 
addressed (and may be a habitat preference); and (4) climate model 
projections do not support complete loss of snow. They also urged us to 
reaffirm prior findings that winter recreation (motorized and 
nonmotorized) is not a threat to wolverines.
    Our Response: Given that our updated analysis and new information 
included in the wolverine SSA report directly relates to our previous 
DPS determination in the 2013 proposed rule, we reevaluated wolverines 
in the contiguous United States under our DPS Policy. See the Distinct 
Population Segment section below for more information. We provide our 
analysis of the status of wolverines in the contiguous United States 
below in the Determination of Species Status. The topic of denning 
behavior is discussed in the wolverine SSA report (see Use of Dens and 
Denning Behavior discussion in the Reproduction and Growth section in 
the wolverine SSA report (Service 2018, pp. 23-28)). For our analysis 
of the effects of climate change to wolverines and denning habitat, see 
Climate Change and Potential for Cumulative Effects below.
    (13) Comment: We received a comment from an industry group stating 
that our decision to prepare the February 4, 2013, proposed rule (78 FR 
7864) to list the North American wolverine as threatened was due to a 
``misreading'' of the Service's obligation under our 2011 Settlement 
Agreement, and therefore the proposed rule was not developed from ``an 
open-ended scientific inquiry.'' We received a comment from an industry 
group stating that the Service should not ``revert back to the 2013 
proposed rule'' and should conduct a new analysis of potential impacts 
to the species, revise the proposed listing using newly available 
information, and reevaluate our previous DPS determination.
    Our Response: The Service properly prepared its 2013 proposed rule. 
On October 18, 2016, we published a document in the Federal Register 
(81 FR 71670) announcing that we would initiate a new status review of 
the North American wolverine, to determine whether this DPS meets the 
definition of an endangered or threatened species

[[Page 64624]]

under the Act, or whether the species is not warranted for listing. The 
Service has prepared the wolverine SSA report that includes discussion 
and analyses of the best available scientific information regarding 
life history, biology, and consideration of current and future 
vulnerabilities. This information was used to evaluate the current and 
future conditions of the species, and to inform our current 
determination.

Comments From Tribes

    (14) Comment: We received comments from one consortium of Tribal 
nations stating that, based on the weight of evidence provided in our 
previous rules, the North American wolverine meets the definition of 
endangered or threatened and is therefore warranted for listing. 
Specific threats mentioned in the comment letter included current 
population status, winter recreation activities, and effects of climate 
change. The Tribes also included comments documenting the cultural 
value of the wolverine and connection to cultural practices and concern 
for the loss of wolverine populations in the contiguous United States. 
The Tribes encouraged the Service to use sound and solid science in the 
listing determination, and noted that additional population monitoring 
and Tribal climate change modeling efforts are under way to evaluate 
the status of the wolverine.
    Our Response: We appreciate the unique perspective provided by the 
Tribal nations regarding the contribution of the North American 
wolverine to the Tribes' culture and spirituality. We also appreciate 
the commitment of the Tribal nations to continue ongoing studies of 
wolverines.
    As described in the wolverine SSA report, we evaluated new 
information, as well as information not previously considered, and 
contacted several wolverine researchers (both within and outside the 
United States) to provide a more detailed description of the 
wolverine's life history and ecology, including a detailed discussion 
of wolverine denning habitat and behavior. We conducted new analyses to 
develop a current potential extent of occupancy using the most recent 
verified observations. Current potential extent is the perimeter of the 
outermost geographic limits based on all (available) occurrence records 
(that is, the maximum extent of occurrences) of a species minus those 
areas where we believe the species has been extirpated (Service 2017). 
Conservation measures and regulatory mechanisms relative to the 
wolverine were also provided in the wolverine SSA report. This 
information was used to evaluate the current (potential stressors) and 
future conditions of the species, and inform our current determination. 
We evaluated results from a fine-scale analysis of the potential 
effects of climate change to future snowpack conditions in two regions 
of the Rocky Mountains. This analysis found that significant areas 
(several hundred km\2\/mi\2\) will persist on May 1 at elevations used 
by wolverines for denning. We determined that, based on the best 
available information, the North American wolverine in the contiguous 
United States does not warrant listing as threatened or endangered 
under the Act.
    (15) Comment: We received comments from one Tribe whose aboriginal 
territory is occupied by the North American wolverine. The Tribe 
submitted a comment letter in 2013 supporting our proposed listing. The 
Tribe stated that the conservation and restoration of the wolverine and 
other species within this homeland is of great importance to the 
Tribe's subsistence, culture, religion, and economy. The letter also 
identified conservation and management plans currently under 
development and highlighted that the wolverine is designated as a 
species of concern in these current draft plans. Specific comments were 
provided relative to threats from climate change (including relative to 
demographic stochasticity), recreation and urban development, and 
incidental take. Included in those comments were references to other 
studies under way (e.g., Adaptation Partners and climate change 
vulnerability assessments; winter recreation study) to evaluate these 
potential stressors.
    Our Response: We appreciate the perspective provided regarding the 
importance of the wolverine and other species to the Tribe and its 
commitment to current and future conservation and management actions. 
We also appreciate and evaluated the information presented in the 
citations that were provided in the comment letter. As described in the 
wolverine SSA report, we evaluated several new scientific publications 
and information not previously considered in preparing a new status 
review. This information was used to evaluate the current conditions 
(i.e., potential stressors, including winter recreation) and future 
conditions (e.g., effects of climate change) of the species. Based on 
the best available information, we determined that the North American 
wolverine in the contiguous United States does not warrant listing as 
threatened or endangered under the Act.

State Agency Comments

    We received extensive comments from several western States, 
requesting that we consider previously submitted comments in response 
to our previously proposed listing rule (78 FR 7864; February 4, 2013) 
as well as additional comments submitted in response to our 2016 notice 
reopening public comment (81 FR 71670; October 18, 2016). These 
comments were grouped together and summarized as described below:
    (16) Comment: We received detailed comments critical of our 
reliance on ``unverified'' climate model projections in our 2013 
proposed rule, the lack of discussion of assumptions in adopting the 
model findings, the lack of evaluating alternative hypotheses, and the 
need to evaluate these effects at the den-site scale. One State agency 
recommended that, given the disagreements in the scientific community 
on the interpretation of these results, the Service solicit an 
independent, scientific review of the proposed rule.
    Our Response: This withdrawal was based on the scientific analysis 
using the structure of the Service's Species Status Assessment (SSA) 
Framework (https://www.fws.gov/endangered/improving_ESA/ssa.html). An 
SSA is a focused and rigorous assessment of a species' ability to 
maintain self-sustaining populations over time. This assessment is 
based on the best available scientific and commercial information 
regarding life history, biology, and consideration of current and 
future vulnerabilities. The result is a single document (SSA report) 
that delivers foundational science for informing decisions under the 
Act, including listing determinations, consultations, grant 
allocations, permitting, and recovery planning.
    In preparing the final SSA report for the North American wolverine 
(available at www.regulations.gov, at Docket No. FWS-R6-ES-2016-0106), 
we reviewed available reports and peer-reviewed literature, 
incorporated survey information for the purpose of preparing updated 
maps of the known species' current and historical occurrences, and 
contacted species experts to collect additional unpublished 
information. We evaluated the appropriate analytical tools to address 
data gaps and uncertainties. In some instances, we used publications 
and other reports of the Eurasian subspecies (Gulo gulo gulo) to fully 
inform our knowledge of the North American wolverine (Gulo gulo 
luscus).
    Before finalizing the SSA report, the draft wolverine SSA report 
was

[[Page 64625]]

submitted for peer review to four independent peer reviewers in 
accordance with our July 1, 1994, peer review policy (59 FR 34270), the 
Service's August 22, 2016, Director's Memo on the Peer Review Process, 
and the Office of Management and Budget's December 16, 2004, Final 
Information Quality Bulletin for Peer Review (revised June 2012). 
Results of this structured peer review process can be found at https://www.fws.gov/mountain-prairie/science/peerReview.php. This draft was 
also submitted to our Federal, State, and Tribal partners for 
scientific review. In preparing this determination to withdraw the 
proposed rule, we incorporated the results of these reviews in the 
final wolverine SSA report, as appropriate.
    As noted in our previous responses to public comments (see response 
to Comments 1 and 5 above), in our wolverine SSA report, we recognize 
that current climate trends and future (2055 and later) climate model 
projections indicate warming temperatures for much of western North 
America, and changes to snow pack conditions. Our review of the 
literature found that, overall, higher elevation areas (e.g., Rocky 
Mountains, Sierra Nevada Mountains) are more resilient to projected 
changes in temperature and precipitation as compared to lower 
elevations (Wobus et al. 2017, p. 12). In general, models indicate 
higher elevations will retain more snow cover than lower elevations, 
particularly in early spring (April 30/May 1). We present in the 
wolverine SSA report a summary of new, fine-scale analysis of future 
snow persistence in two regions of the western United States, Glacier 
National Park and Rocky Mountain National Park. Glacier National Park 
represents a high-latitude and relatively low-elevation area currently 
occupied by North American wolverines. Rocky Mountain National Park is 
a lower latitude and high-elevation area within the North American 
wolverine's historical range, which was occupied by a male wolverine 
from 2009 to at least 2012.
    As described above in Comment 5, this new analysis built upon 
previous model projections presented in McKelvey et al. (2011), but 
with significant differences such as finer spatial resolution, 
incorporation of slope and aspect, snow depth estimates, additional 
years of historical data, and wider temporal analyses of snow 
persistence (April-June). Details of this modeling exercise are 
presented in Ray et al. (2017), and summarized in the wolverine SSA 
report. That analysis indicates large areas (several hundred km\2\/
mi\2\ for each study area) of future snow (greater than 0.5 m (20 in) 
in depth) will persist on May 1 at elevations currently used by 
wolverines for denning. This is true, on average, across the range of 
climate models used out to approximately year 2055.
    After reviewing studies not previously considered and new studies/
publications made available after the 2013 and 2014 proposed rules, we 
present in the wolverine SSA report, a detailed discussion of the North 
American wolverine's physiology and other life-history characteristics 
(e.g., reproductive behavior). The analysis speaks to several presumed 
aspects of the relationship of denning behavior and other needs of this 
species regarding the presence of persistent spring snow.
    Also, see our response to Comment 5 above for a short summary and 
our SSA report for more details regarding our analysis of the effects 
of climate change to denning habitat.
    (17) Comment: We received comments critical of our previous support 
for findings by Schwartz et al. 2009 regarding effective population 
size. Relatedly, several States commented on recent dispersal/movements 
of wolverines into California, Colorado, and Utah as evidence of 
population expansion.
    Our Response: See our response to Comment 2 above for a discussion 
of effective population size. Regarding recent occurrences of 
wolverines in the contiguous United States, wolverines have recently 
been found in areas where they were once extirpated in the contiguous 
United States. See the Population Abundance and Density section below 
for more information.
    (18) Comment: We received comments from several western States 
presenting clarifications or updates to incidental trapping events and 
trapping regulations.
    Our Response: In the wolverine SSA report, we include a summary of 
trapping or hunting of wolverines in the contiguous United States. At 
the present time, trapping or hunting of wolverines is not allowed in 
any western State (with the exception of Alaska, which was not included 
in the DPS in our proposed rule). Legal protections for wolverines are 
codified in western State laws and regulations concerning hunting and 
trapping. These protections include: Endangered in Colorado, threatened 
in California and Oregon, candidate species in Washington, non-game 
species protections in Idaho and Wyoming, a species of concern and 
furbearer with a closed season in Montana, and protection from 
collection, importation, and possession in Utah. Since 2013, there has 
been a zero quota for trapping or harvest of wolverine in Montana.
    Incidental trapping of wolverines has been documented in the 
contiguous United States (as recently as December 2017), though not all 
events have resulted in mortality (see response to Comment 3 above). 
Both Idaho and Montana are implementing trapper education programs to 
minimize nontarget wolverine captures.
    (19) Comment: Several States provided comments in response to our 
2013 proposed rule and to our 2016 reopening of the public comment 
period indicating their disagreement with our determination of a DPS 
for the contiguous United States. Specifically, some commenters stated 
that the criteria of significance should be reevaluated, noting that 
the proposed rule did not provide any substantive information to 
support our conclusion that the loss of the wolverine in the contiguous 
United States would result in a significant gap in the range of the 
species; that is, our previous use of the loss of latitudinal range 
does not provide a rational basis for concluding that the loss of the 
wolverine in the contiguous United States would be significant in 
relation to the taxon. Another commenter stated that the wolverine 
population in the contiguous United States is connected geographically 
and genetically to the Canada/Alaska populations and these northern 
populations were likely the source of recolonization during the 20th 
century. Further, this commenter stated there is not a difference in 
control of exploitation and conservation status between the United 
States and Canada.
    Another commenter noted that, throughout the 2013 proposed rule, 
the Service acknowledged that, historically, the wolverine population 
in the contiguous United States was markedly reduced by systematic 
predator control programs and unregulated trapping. Yet, as the 
commenter pointed out, areas of suitable habitat in the North Cascades, 
where trapping has been minimal or nonexistent for decades, and 
northern Rockies, were recolonized by animals from Canada, where 
relatively liberal trapping is still allowed. Thus, our 
characterization in the 2013 proposed rule of ``liberal'' Canadian 
regulations as sufficient to ``maintain the robust conservation status 
of the Canadian population,'' does not comport with our 
characterization that the very limited trapping in the contiguous 
United States (Montana only) is insufficient to maintain the rebounding 
population designated as a DPS.

[[Page 64626]]

    Our Response: In light of the updated analysis and new information 
included in the wolverine SSA report, we reevaluated wolverines in the 
contiguous United States under our DPS Policy. We conclude that the 
population of wolverines in the contiguous United States is not 
discrete in relation to the remainder of the species in North America. 
As a result, the population of wolverines in the contiguous United 
States is not a listable entity under section 3(16) of the Act. See the 
Distinct Population Segment section below for more information.
    (20) Comment: State agencies provided citations or copies of 
publications and reports relevant to wolverine ecology that were 
published after the 2013 proposed rule.
    Our Response: We appreciate the comprehensive lists of published 
literature and survey reports provided by the State agencies. We 
evaluated this information during the preparation of the wolverine SSA 
report, and have incorporated this information, as appropriate, to 
ensure that the wolverine SSA report presents the best available 
information regarding the status of the North American wolverine.
    (21) Comment: We received information providing background 
information and preliminary results of ongoing collaborative 
conservation efforts being implemented through the WSWCP-Coordinated 
Occupancy Survey.
    Our Response: We appreciate the additional information provided by 
the State agencies participating in the WSWCP-Coordinated Occupancy 
Study. In the wolverine SSA report, we provide a summary of the 
preliminary field and genetic results from the recent WSWCP-Coordinated 
Occupancy Study in four western (contiguous United) States (see 
wolverine SSA report for additional details). We also incorporated 
technical comments received from several State agencies during the 
review of the draft wolverine SSA report into the final report. As 
discussed in the wolverine SSA report, the Western States Wolverine 
Working Group is continuing to develop studies to evaluate wolverine 
population distribution and occupancy, and connectivity across four 
western States.
    (22) Comment: Information was provided by State agencies describing 
the legal protections of wolverines in individual States and 
conservation measures being implemented.
    Our Response: In the wolverine SSA report (Service 2018, Appendix 
G), we provide a detailed discussion of current State (and Federal) 
regulatory mechanisms and other conservation measures that offer 
protections for the North American wolverine. In addition to the WSWCP-
Coordinated Occupancy Study (Service 2018, Appendix B), several western 
States have identified the North American wolverine as a Species of 
Greatest Conservation Need in their State Wildlife Action Plans, and 
the North American wolverine is a focal species of conservation 
strategies for conservation targets in a number of ecoregions (e.g., 
Cascades, Sierra Nevada) that support forested lowlands, subalpine-
high-montane conifer forest where wolverines occur. These State 
designations provide information to assist resource managers with 
proactive decision-making regarding species conservation and data 
collection priorities, and support the conservation of the North 
American wolverine and its habitat.
    (23) Comment: We received a comment from one State agency noting 
that the State does not recognize the North American wolverine as a 
native species due to lack of evidence that a population ever existed 
within New Mexico (i.e., unverified species); thus, the State does not 
recognize the species in any of its wildlife statutes or regulations.
    Our Response: We appreciate the clarification and information 
provided by the State agency and have considered this in our analysis 
to define the current potential extent of occurrence for the North 
American wolverine in the contiguous United States (see Figures 1 and 2 
below) and in our assessment of population status in the wolverine SSA 
report. In their analysis of wolverine distribution records in the 
contiguous United States, Aubry et al. (2001, p. 2,150) identified 1860 
as the most recent verifiable documentation of wolverine in northern 
New Mexico. We received two unverified accounts of wolverine sightings 
in New Mexico from the general public during the most recent public 
comment period. We are unaware of any recent verifiable individuals or 
populations of wolverines in New Mexico.
    (24) Comment: In response to our request for information in our 
October 18, 2016, Federal Register document (81 FR 71670), we received 
comments from the U.S. Forest Service submitting verifiable and new 
records of wolverines from 2000 to 2016. These records include 
observations from camera surveys by both governmental and 
nongovernmental organizations, photos from private citizens, and 
locations from a regional study.
    Our Response: We appreciate the information provided and 
incorporated these observations and detections in our analysis to 
define the current potential extent of occurrence for the North 
American wolverine in the contiguous United States (see Figures 1 and 2 
below) and in our assessment of population status in the wolverine SSA 
report.

Background

    A comprehensive review of the life history, population trends, and 
ecology of the North American wolverine is presented in the wolverine 
SSA report (Service 2018, pp. 3-44). The Service recognizes the North 
American wolverine as the subspecies Gulo gulo luscus (Service 2018, p. 
8). Wolverines are a medium-sized (about 1 m (3.3 ft) in length) 
carnivore, with a large head, broad forehead, and short neck (Service 
2018, p. 4). Wolverines have heavy musculature and relatively short 
legs, and large feet with strong, curved claws for digging and climbing 
(Service 2018, p. 4). Their feet are adapted for travel through deep 
snow and, during the winter, dense, stiff, bristle-type hairs are found 
between the toes and around the foot pad; this characteristic becomes 
diminished in the summer (Service 2018, p. 4). The wolverine is the 
largest terrestrial member of the Mustelidae family (weasels, fisher, 
mink, marten, and others) and resembles a small bear with a bushy tail 
(Service 2018, p. 1). Wolverines possess a number of morphological and 
physiological adaptations that allow them to travel long distances and 
they maintain large territories in remote areas (Service 2018, p. 1). 
They have been described as curious, intelligent, and playful, but 
cautious animals, though their social behavior and social organization 
has not been well-studied (Service 2018, p. 1). Wolverines have a 
distribution that includes the northern portions of Europe, Asia, and 
North America. In North America, they are found in Alaska, much of 
Canada, and the western-northwestern United States.
    During the late 1800s and early 1900s, the wolverine population 
declined or was extirpated in much of the contiguous United States 
(lower 48 States), which has been largely attributed to unregulated 
trapping (Hash 1987, p. 583). Wolverine numbers have recovered to some 
extent from this decline and, in the United States, wolverines are 
currently found in parts of Washington, Oregon, Idaho, Montana, 
Wyoming, California (single male), and Alaska, and as recently as 2010 
in Michigan, 2012 in Colorado, and 2016 in Utah. Known reproducing 
wolverine populations are found in Washington, Idaho, Montana, and 
Wyoming (Service 2018, p. 1).

[[Page 64627]]

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species is an ``endangered species'' or a ``threatened 
species.'' The Act defines an endangered species as a species that is 
``in danger of extinction throughout all or a significant portion of 
its range,'' and a threatened species as a species that is ``likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range.'' The Act requires that we 
determine whether any species is an ``endangered species'' or a 
``threatened species'' because of any of the following 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.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the expected response by the species, 
and the effects of the threats--in light of those actions and 
conditions that will ameliorate the threats--on an individual, 
population, and species level. We evaluate each threat and its expected 
effects on the species, then analyze the cumulative effect of all of 
the threats on the species as a whole. We also consider the cumulative 
effect of the threats in light of those actions and conditions that 
will have positive effects on the species, such as any existing 
regulatory mechanisms or conservation efforts. The Secretary determines 
whether the species meets the definition of an ``endangered species'' 
or a ``threatened species'' only after conducting this cumulative 
analysis and describing the expected effect on the species now and in 
the foreseeable future.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis. The term 
``foreseeable future'' extends only so far into the future as the 
Services can reasonably determine that both the future threats and the 
species' responses to those threats are likely. In other words, the 
foreseeable future is the period of time in which we can make reliable 
predictions. ``Reliable'' does not mean ``certain''; it means 
sufficient to provide a reasonable degree of confidence in the 
prediction. Thus, a prediction is reliable if it is reasonable to 
depend on it when making decisions.
    It is not always possible or necessary to define foreseeable future 
as a particular number of years. Analysis of the foreseeable future 
uses the best scientific and commercial data available and should 
consider the timeframes applicable to the relevant threats and to the 
species' likely responses to those threats in view of its life-history 
characteristics. Data that are typically relevant to assessing the 
species' biological response include species-specific factors such as 
lifespan, reproductive rates or productivity, certain behaviors, and 
other demographic factors.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological status review for the species, including an assessment of 
the potential threats to the species. The SSA report does not represent 
a decision by the Service on whether the species should be proposed for 
listing as an endangered or threatened species under the Act. It does, 
however, provide the scientific basis that informs our regulatory 
decisions, which involve the further application of standards within 
the Act and its implementing regulations and policies. The following 
sections provide summaries of the key results and conclusions from the 
SSA report; the full SSA report can be found on the Mountain-Prairie 
Region website at https://www.fws.gov/mountain-prairie/ and at http://www.regulations.gov under Docket No. FWS-R6-ES-2016-0106.
    To assess wolverine viability, we used the three conservation 
biology principles of resiliency, redundancy, and representation 
(Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency supports the 
ability of the species to withstand environmental and demographic 
stochasticity (for example, wet or dry, warm or cold years), redundancy 
supports the ability of the species to withstand catastrophic events 
(for example, droughts, large pollution events), and representation 
supports the ability of the species to adapt over time to long-term 
changes in the environment (for example, climate changes). In general, 
the more resilient and redundant a species is and the more 
representation it has, the more likely it is to sustain populations 
over time, even under changing environmental conditions. Using these 
principles, we identified the species' ecological requirements for 
survival and reproduction at the individual, population, and species 
levels, and described the beneficial and risk factors influencing the 
species' viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical 
and current condition of the species' demographics and habitat 
characteristics, including an explanation of how the species arrived at 
its current condition. The final stage of the SSA involved making 
predictions about the species' responses to positive and negative 
environmental and anthropogenic influences. This process used the best 
available information to characterize viability as the ability of a 
species to sustain populations in the wild over time. We use this 
information to inform our regulatory decision.

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

[[Page 64628]]

Regarding the Recognition of Distinct Vertebrate Population Segments 
under the Act (61 FR 4722; February 7, 1996). 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, an endangered or threatened species). Discreteness refers 
to the degree of isolation of a population from other members of the 
species, and we evaluate this factor 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. When 
determining if a potential DPS is significant, our policy directs us to 
sparingly list DPSs while encouraging the conservation of genetic 
diversity. If we determine that a population segment is both discrete 
and significant, we then evaluate it for endangered or threatened 
species status based on the Act's standards.
    Both new and updated information and analyses presented in the 
wolverine SSA report, summarized below in support of our listing 
determination, along with public comment, have prompted us to 
reevaluate our previous assessment of the DPS (presented in our 2013 
proposed listing rule, which in turn relied on the DPS analysis 
completed in our 2010 12-month finding) with respect to wolverine in 
the contiguous United States. Below we provide our revised evaluation 
of discreteness under the DPS policy of the segment of the North 
American wolverine occurring in the contiguous United States.

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 
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). Discreteness Based on Marked 
Separation
    In our February 4, 2013, proposed listing rule (78 FR 7864), we did 
not rely on marked separation from other populations to support 
discreteness of the contiguous United States wolverine population. As 
supported by information in the SSA report, we maintain that there are 
no physical, physiological, ecological, or behavioral factors 
separating wolverines in the contiguous United States from wolverines 
in Canada. We do not consider wolverines in the contiguous United 
States to be genetically isolated from wolverines in Canada (McKelvey 
et al. 2014; Pilgrim and Schwartz 2018). Therefore, wolverines in the 
contiguous United States are not discrete based on marked separation 
from other populations of the same taxon.

Discreteness Based on the International Border--Legal Status Conveyed 
by National, State, and Provincial Governments; Differences in Control 
of Exploitation

    Our 2013 proposed rule (78 FR 7864), which incorporated by 
reference our DPS analysis from our 2010 12-month finding, found there 
was no significant difference between the legal status of wolverines 
between Canada and the United States (75 FR 78030; December 14, 2010). 
In the wolverine SSA report, we provide an updated assessment of legal 
protections and regulatory mechanisms for wolverine in North America 
(Service 2018, pp. 70-71, Appendix G). Legal protections in the 
contiguous United States include State listing in California and Oregon 
(threatened), endangered in Colorado, a candidate species in 
Washington, non-game species protections in Idaho and Wyoming, a 
species of concern and furbearer with a closed season in Montana, and 
protected from collection, importation, and possession in Utah. In 
Canada, provincial designations range from endangered to threatened in 
eastern provinces, and sensitive/special concern to no ranking in other 
provinces (definitions provided by the Committee on the Status of 
Endangered Wildlife in Canada, 2014). As was determined in our 2013 
proposed listing rule (78 FR 7864), we again find no significant 
differences in legal status.
    In the 2010 12-month finding (75 FR 78030) and reiterated in our 
2013 proposed listing rule (78 FR 7864), we stated that differences in 
control of exploitation exist, but favor the contiguous United States 
population. Trapping or hunting of wolverines is currently prohibited 
in the contiguous United States and regulated as appropriate in Canada 
(Service 2018, pp. 68-69). In the wolverine SSA report, we included a 
new analysis of trapping in southern Canada and trapping effort along 
the U.S.-Canada border, which we found to be limited. Thus, we conclude 
that the differences in exploitation are not significant in light of 
section 4(a)(1)(D) of the Act (inadequacy of existing regulatory 
mechanisms).

Discreteness Based on the International Border--Differences in 
Management of Habitat

    As we outlined in the proposed 4(d) rule (78 FR 7888) management 
activities (e.g., timber harvest, wildland firefighting, prescribed 
fire, and silviculture) can modify wolverine habitat, but this 
generalist species appears to be little affected by changes to the 
vegetative characteristics of its habitat. In addition, most wolverine 
habitat occurs at high elevations in rugged terrain that is not 
conducive to intensive forms of silviculture and timber harvest. 
Habitat management is not a conservation need for wolverine. Therefore, 
differences in management of habitat between the United States and 
Canada are not significant in light of section 4(a)(1)(D) of the Act.

Discreteness Based on the International Border--Differences in 
Conservation Status

    In the December 14, 2010, 12-month finding (75 FR 78030), which is 
incorporated and discussed in the February 4, 2013, proposed listing 
rule (78 FR 7864), we found that the wolverine population in the 
contiguous United States met the second DPS discreteness condition 
because of

[[Page 64629]]

differences in conservation status as delimited by the U.S.-Canada 
international governmental boundary. We found that those differences 
were substantial and significant in light of section 4(a)(1)(D) of the 
Act. We stated that in the remaining current range in Canada and 
Alaska, wolverines exist in well-distributed, interconnected, large 
populations. We added that, conversely, wolverine populations in the 
remaining United States range appear to be at numbers so low that their 
continued existence could be at risk, especially in light of the 
threats to the species. In the 2010 finding, we stated that 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 habitat. We stated 
it was 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. As a result, we 
concluded that the contiguous United States population of the wolverine 
meets the discreteness criterion in our DPS Policy (61 FR 4722, 
February 7, 1996). Consequently, we used the international border 
between the United States and Canada to define the northern boundary of 
the contiguous United States wolverine DPS in our December 14, 2010, 
12-month finding (75 FR 78030) and our February 4, 2013, proposed 
listing rule (78 FR 7864). Below we provide a reevaluation of that 
determination supported by information presented in the wolverine SSA 
report.
    Small Total Population Size--Wolverine densities vary across North 
America and have been described as naturally low (van Zyll de Jong 
1975, p. 434); wolverine populations are naturally uncommon given the 
species' large home range, wide-ranging movements, and solitary 
characteristics (Service 2018, p. 56). There are many fewer wolverines 
in the contiguous United States than there are in Canada and Alaska 
(Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 
2014, p. 36; Inman et al. 2013, p. 282; Service 2018, p. 71), but this 
is more a reflection of the amount of suitable habitat available within 
the contiguous United States (both currently and historically) for a 
species that needs large exclusive territories, than it is a reflection 
of poor conservation status. Wolverines in Canada are considered to 
occur as a single large group as they are easily able to move between 
areas of suitable habitat and because wolverine habitat is relatively 
contiguous (Harrower 2017, pers. comm.). However, wolverines in the 
contiguous United States are considered to be a metapopulation 
connected with wolverine populations in Canada (Inman et al. 2013, p. 
277). Wolverines currently occupy areas in the contiguous United States 
where they were once extirpated and continue to repopulate the 
contiguous United States after decades of unregulated trapping, 
hunting, and poisoning (Service 2018, p. iv). The same holds true for 
Canada, where wolverines are being detected in areas once extirpated 
(COSEWIC 2014, p. v).
    These movement patterns are supported by recent genetic information 
that indicates wolverines from Canada have slowly repopulated the 
contiguous United States over the past century since the era of 
unregulated persecution (Service 2018, pp. 45-50). This point is 
discussed in detail below in the Genetic Diversity section of this 
withdrawal. We stated in the December 14, 2010, finding that 
differences in population sizes between the contiguous United States 
and Canada were reflective of a difference in conservation status (75 
FR 78030). However, based on new information, we now conclude that the 
contiguous United States wolverines represent a peripheral population 
at the southern extent of the North American wolverine range. Thus, we 
now consider the small population size of wolverines in the United 
States to be a natural result of habitat fragmentation and not 
reflective of a difference in conservation status (see Habitat 
Fragmentation below for more detail). Therefore, any difference in 
population size on the contiguous United States side of the 
international border is not a significant difference in conservation 
status in light of section 4(a)(1)(D) of the Act as it applies to 
discreteness.
    Effective Population Size--Effective population size 
(Ne) is defined as ``the size of an idealized population 
that would experience the same amount of genetic drift and inbreeding 
as the population of interest (Service 2018, Box 2). In popular terms, 
Ne is the number of individuals in a population that 
contribute offspring to the next generation'' (Hoffman et al. 2017, p. 
507). Effective population size can be interpreted differently 
depending on how it's defined and used, and the concept of effective 
population size (Ne) (see review by Wang et al. 2016) and, 
relatedly, minimum viable population, has been a topic of debate, 
particularly the 50/500 rule (population size of 50 for short-term, and 
500 for long-term genetic health). Importantly, the concept and 
guidelines for genetically effective population size were developed for 
a single, isolated population (Laikre et al. 2016, p. 280). The term 
``effective population size'' is not a meaningful term unless 
additional context is provided relative to which concept of population 
size is being evaluated (Ewens 1990, p. 309). Demographic factors are 
needed when interpreting actual population size from an effective 
population size; thus, there is no justification for a fixed, 
genetically derived minimum viable population size value of `500' as 
each case is unique and is dependent on such factors as sex ratio, 
subpopulations, dispersal, and immigration (Ewens 1990, pp. 311-313).
    As noted above, we do not consider the wolverine population in the 
contiguous United States to be genetically isolated from wolverines on 
the other side of the international border in Canada. In the wolverine 
SSA report, we provide a contextual discussion of the effective 
population size concept, particularly in the context of genetic studies 
related to the phylogeographic history of the North American wolverine 
(Service 2018, pp. 45-50), which was not well described in the 2013 
proposed rule. In sum, the spatial distribution of genetic variability 
currently observed in wolverines in North America appears to be a 
reflection of a complex history in which population abundance has 
fluctuated since the time of the last glaciation with insufficient time 
passing since human persecution, since at least the 1700s, to allow for 
full recovery of wolverine densities (Cardinal 2004, pp. 23-24; 
Zigouris et al. 2012, p. 1,554). This history and the fact that 
wolverines in the contiguous United States occupy the southern 
periphery of its entire North American range are important 
considerations. The wolverine SSA report also presents information from 
genetic and observational studies that provide support for wolverine 
movement across the international border of the contiguous United 
States and Canada (Aubry et al. 2016, pp. 16, 20; Lucid et al. 2016, p. 
184; Service 2018, pp. 9-23). Thus, we consider wolverines that occupy 
the contiguous United States to be genetically continuous with 
wolverines in adjacent Canadian provinces.
    Wolverines travel (disperse) through areas outside high-elevation, 
forested habitats. For example, tracked movements of a male wolverine, 
M56, from Wyoming into Colorado and its subsequent discovery in North 
Dakota, indicate extensive travel outside of

[[Page 64630]]

modeled primary wolverine habitat (i.e., Inman et al. 2013), including 
through arid grasslands and shrubland habitats of the Wyoming Basin 
ecoregion (Packila et al. 2017, entire). This animal's movement also 
supports some level of connectivity (and potential gene flow) between 
currently occupied habitat (Wyoming) and unoccupied habitat within the 
wolverine's historical range (Colorado) (Packila et al. 2017, p. 404). 
Similarly wolverines in the North Cascades region have moved from 
Washington and Idaho into British Columbia, and from Montana to British 
Columbia and Alberta (Service 2018, p. 45). Based on genetic analyses, 
the male wolverine currently occupying an area within the Sierra Nevada 
Mountains of California also represents evidence of connectivity 
between wolverine populations of the Rocky and Sierra Nevada Mountain 
Ranges (Moriarty et al. 2009, p. 154). Within the Southwestern Crown of 
the Continent (SWCC) in northwestern Montana, cross-valley movements of 
wolverines have been detected, which researchers believe is an 
indication of good connectivity in this region (SWCC Working Group 
2016, pers. comm.).
    A preliminary mitochondrial DNA analysis was prepared for wolverine 
samples collected during the winters of 2015-2016 and 2016-2017 as part 
of the Western States Wolverine Conservation Project--Coordinated 
Occupancy Survey (Pilgrim and Schwartz 2018, entire). All 45 wolverines 
identified from samples collected in Idaho, Montana, and Wyoming match 
haplotype Wilson-A, which is common throughout the Rocky Mountains, 
Alaska, and Canada, while all 5 wolverines identified from samples 
collected in Washington match haplotype Wilson-C (Pilgrim and Schwartz 
2018, p. 3). Previous analyses of recent or modern (1989-2012) samples 
from the Cascades Range in northern Washington and southern British 
Columbia, as presented in McKelvey et al. (2014, p. 328), were 
characterized as haplotype C, and one historical (defined in this study 
as pre-1930) sample as haplotype A (McKelvey et al. 2014, p. 327). 
Outside of this region, haplotype C has been found only in Alberta, 
Saskatchewan, and Nunavut provinces (McKelvey et al. 2014, p. 330). 
Based on mitochondrial DNA, McKelvey et al. (2014, p. 330) concluded 
that modern (defined in their study as 1989-2012) wolverine populations 
in the contiguous United States are the result of recolonization 
(following persecution during a period of unregulated hunting or 
trapping and poisoning) from the north. The additional mitochondrial 
analysis from samples collected in 2015, 2016, and 2017 provides 
further support that all contiguous United States historical (pre-1900) 
and recent wolverine populations are likely descendants of immigrants 
from Canada.
    The 2013 proposed rule presented an effective population size 
estimate for wolverines in the contiguous United States from a 
publication by Schwartz et al. (2009), which estimated a summed 
effective population size of 35, with credible limits from 28 to 52 
(Schwartz et al. 2009, p. 3,226). As described in the wolverine SSA 
report, the study used wolverine samples from the main part of the 
Rocky Mountain wolverine populations and did not include subpopulations 
from two other mountain regions in Montana, and samples were missing 
from other parts of the wolverine range in Idaho and other areas of 
Montana. Thus, the analysis missed wolverine subpopulations and 
individuals, which would underestimate the results for this type of 
analysis. Furthermore, a small effective population size would be more 
of a concern if the population was in isolation; however, wolverines in 
the contiguous United States are not genetically or physically isolated 
from wolverines in Canada.
    To summarize, the currently known spatial distribution of genetic 
variability in wolverines in North America appears to be a reflection 
of a complex history where population abundance has fluctuated since 
the time of the last glaciation and insufficient time has passed since 
human persecution for a full recovery of wolverine densities (Cardinal 
2004, pp. 23-24; Zigouris et al. 2012, p. 1,554). Zigouris et al. 
(2012, p. 1,545) noted that the genetic diversity reported in Cegelski 
et al. (2006) and Kyle and Strobeck (2001, 2002) for the southwestern 
edge of the North American range represented only part of the diversity 
in the northern populations of wolverines. Zigouris et al. (2012, p. 
1,545) posit that the irregular distribution of wolverines in the 
southwestern periphery and the genetic diversity observed in those 
analyses is a result of population bottlenecks that were caused by 
range contractions from a panmictic (random mating) northern core 
population approximately 150 years ago coinciding with human 
persecution. Recent dispersals of wolverines into Colorado (2009), 
California (2008), and Utah (2014) provide evidence for connectivity 
and the potential for gene flow between Northern Rocky Mountain 
populations and areas where wolverines were extirpated. As noted above, 
there is also recent evidence of wolverine movement across the 
international border. Furthermore, our analysis of trapping levels in 
the wolverine SSA report does not support previous assumptions that 
trapping in Canada near the border acts as a barrier to wolverine 
movement into the contiguous United States (Service 2018, pp. 68-69). 
Finally, very few successful migrants are needed per generation to 
maintain at least 95 percent of the genetic variation in the next 100 
generations (approximately 750 years) in the contiguous United States 
(Cegelski et al. 2006, p. 209).
    We conclude that this level of migration from the north has already 
been occurring following the end of intense persecution of this 
species; wolverines are currently observed in previously occupied areas 
within the contiguous United States. Given the recent observations of 
wolverines moving vast distances over varied terrain and across the 
U.S.-Canada border, our recent assessment of the low levels of trapping 
mortality in Canada near the border, and further confirmation of Canada 
as the source of wolverine genetics present in contiguous United States 
wolverines, we believe that wolverines in the contiguous United States 
are not separated genetically from the larger population in Canada. 
Wolverines in the contiguous United States exhibit genetic and 
phenotypic similarities with wolverines in Canada that implies 
connectivity with Canada. As such, we conclude that it is not 
biologically appropriate to consider the low effective population size 
of wolverines on the contiguous United States side of the border as a 
difference in conservation status that is significant in light of 
section 4(a)(1)(D) of the Act as it applies to discreteness. For 
additional information related to wolverine genetic diversity and 
effective population size, see Genetic Diversity below and the 
wolverine SSA report (Service 2018, pp. 45-50).
    Habitat Fragmentation--In our 2010 12-month finding (incorporated 
into the 2013 proposed listing rule), we stated that wolverine habitat 
in the contiguous United States consists of small, isolated islands of 
high-elevation habitat separated from each other by low valleys of 
unsuitable habitat. We also described that these `habitat islands' are 
represented by areas containing spring snow, citing Copeland et al. 
(2010). We concluded that 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

[[Page 64631]]

connectivity between subpopulations, and this also makes them more 
vulnerable to external threats (75 FR 78030; December 14, 2010).
    Our previous analysis of wolverine habitat fragmentation relied 
upon the assumption that wolverines are constricted to habitats that 
contain deep, persistent spring snow cover and, therefore, are more or 
less confined to areas that were defined by the Copeland et al. (2010) 
spring snow cover model. However, wolverines are observed in and move 
through areas without snow cover (e.g., male wolverines dispersing to 
California and Colorado), and female wolverines have successfully 
denned in areas outside previously modeled projections of deep, 
persistent spring snow cover (e.g., Webb et al. 2016; Persson 2017, 
pers. comm.; Jokinen 2018, pers. comm.).
    We now conclude that it is not accurate to categorize the occupied 
habitat of wolverines in the contiguous United States as `habitat 
islands.' As discussed above, wolverine populations in the contiguous 
United States represent the southern periphery of a much larger range 
of the North American wolverine due to naturally occurring landscape 
features such as high elevation and topographic roughness of mountain 
regions. Thus, the distribution of persistent spring snow cover in 
mountainous regions does not represent the only determining habitat 
feature for wolverines. The availability of prey and avoidance of 
predators are also important elements of wolverine habitat (Inman et 
al. 2012, p. 785; Scrafford et al. 2017, p. 34)). As described in the 
SSA report, wolverines use a unique and productive ecological niche 
that allows them to occupy high-elevation regions across the 
northwestern portion of the contiguous United States (Service 2018, pp. 
27, 38). Finally, as noted above, wolverine movement in the contiguous 
United States is not constrained by high-elevation habitat or snow 
cover, and wolverines can easily move and disperse long distances in 
the western United States (e.g., SWCC Working Group 2016, pers. comm.; 
Packila et al. 2017, entire). Therefore, habitat fragmentation in the 
context of availability of persistent spring snow cover or loss of 
connectivity in the contiguous United States is not an appropriate 
difference in conservation status in light of section 4(a)(1)(D) of the 
Act as it applies to discreteness.

Discreteness Based on the International Border--Differences in 
Regulatory Mechanisms

    Because there aren't significant differences in control of 
exploitation, legal conservation status, and management of habitat, nor 
other threats to the wolverine requiring regulatory mechanisms to 
address them, we conclude that there are not differences in regulatory 
mechanisms between the United States and Canada that are significant in 
light of section 4(a)(1)(D).

Conclusion on Discreteness

    Based on our updated analysis described above and supported by 
information in the wolverine SSA report, the contiguous United States 
population of wolverine does not meet the discreteness criterion in our 
DPS Policy (61 FR 4722; February 7, 1996). As a result, the contiguous 
United States population of wolverines does not qualify as a DPS and is 
not a listable entity under section 3(16) of the Act. After determining 
that a vertebrate population is not discrete, we are not required to 
complete an analysis to determine if the population in question is 
significant according to our DPS Policy.

DPS Conclusion

    Based on the best available information, we conclude that the 
population of wolverines in the contiguous United States is not 
discrete in relation to the remainder of the species in North America. 
As a result, the population of wolverines in the contiguous United 
States is not a listable entity under section 3(16) of the Act.
    The DPS Policy sets forth a three-step process for determining 
whether a vertebrate population as a separate entity warrants listing: 
(1) Determine whether the population is discrete; (2) if the population 
is discrete, determine whether the population is significant to the 
taxon as a whole; and (3) if the population is both discrete and 
significant, then evaluate the conservation status of the population to 
determine whether it is endangered or threatened. Although we have 
determined that wolverines in the contiguous United States do not 
qualify as a DPS and, therefore, are not a listable entity, we provide 
below a status determination of the wolverine population in the 
contiguous United States. The DPS Policy neither requires nor prohibits 
completion of a status determination once we have determined that a 
population does not qualify as a DPS. Nevertheless, in this instance, 
we concluded that completing an assessment--and detailing the nature, 
scope, and likely effect of the threats to the population and the 
species--would provide us and the public with useful information 
regarding wolverines occupying the contiguous United States.

Summary of Biological Status and Threats

    In preparing the SSA report for the wolverine, we reviewed 
available reports and peer-reviewed literature, incorporated survey 
information, and contacted species experts to collect additional 
unpublished information for the North American subspecies (Gulo gulo 
luscus), including Canada and Alaska. We identified uncertainties and 
data gaps in our assessment of the current and future status of the 
species. We also evaluated the appropriate analytical tools to address 
these gaps and conducted discussions with species experts and prepared 
updated maps of the known species' range in North America. In some 
instances, we used publications and other reports (primarily from 
Fenno-Scandinavia) of the Eurasian subspecies (G. g. gulo) in 
completing this assessment.
    Since the publication of the February 4, 2013, proposed listing 
rule (78 FR 7864), several new wolverine studies have been published 
(e.g., Aronsson 2017, Aronsson and Persson 2016, Aronsson et al. 2017, 
Heinemeyer et al. 2019, Jokinen et al, 2019, Magoun et al. 2017, 
Persson et al. 2017, Stewart et al. 2016, Webb et al. 2016, see 
additional list of citations in the wolverine SSA report), which have 
added to our understanding of wolverine biology while also highlighting 
new insights into identifying key species' needs and their interactions 
with both abiotic and biotic factors. This new information is 
particularly relevant for a difficult-to-study animal like the 
wolverine.
    Using the species, individual, and population needs identified for 
the wolverine and location results from surveys and studies, we 
conducted a geospatial analysis to estimate the current potential 
extent of occurrence for the North American wolverine in North America 
including the contiguous United States (Figure 1; Service 2018). 
``Current potential extent'' represents the perimeter of the outermost 
geographic limits based on all (available) occurrence records (that is, 
the maximum extent of occurrences) of a species minus those areas where 
we believe the species has been extirpated (Service 2017). We then 
evaluated this area and previous estimates of potentially suitable 
habitat in the western-northwestern United States to

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assess the species' current conditions within that region. Our future-
condition analysis includes the potential conditions that the species 
or its habitat may face, that is, the most probable scenario if those 
conditions are realized in the future. This most probable scenario 
includes consideration of the sources that have the potential to most 
likely impact the species at the population or rangewide scales in the 
future, including potential cumulative impacts.
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    Our analysis of potential future effects to the North American 
wolverine and its habitat that are associated with climate change 
(probabilistic estimates for temperature and precipitation) is 
presented in the SSA report and summarized here. This analysis was 
based on downscaled (high resolution local climate information derived 
from global climate models) climate model projections, including a 
detailed study of two regions in the western United States--Glacier 
National Park (currently occupied by reproducing wolverines) and Rocky 
Mountain National Park (occupied by a single male wolverine from 2009 
to at least 2012, but not known to be currently occupied). The two 
regions studied include a high-latitude area near tree line within 
Glacier National Park, where tree line occurs at ~ 1,800 to 2,100 m 
(5,906 to 6,890 ft) that is currently occupied by wolverines; and a 
lower latitude area within Rocky Mountain National Park, where tree 
line occurs at higher elevation (~ 3,500 m (11,483 ft)) (Ray et al. 
2017, p. 2). These sites were selected to bracket the range of latitude 
and elevation wolverines currently occupy in the contiguous United 
States (Ray et al. 2017, p. 2).
    For the purpose of this assessment, we generally define viability 
as ``consisting of self-sustaining populations that are well 
distributed throughout the species' range,'' and where ``[s]elf-
sustaining populations are those that are sufficiently abundant and 
have sufficient genetic diversity to display the array of life history 
strategies and forms that will provide for their persistence and 
adaptability in the planning area over time'' (Committee of Scientists 
1999, p. 38). We use a timeframe of approximately 38 to 50 years for 
assessing future effects to wolverine viability. This timeframe 
captures consideration of the projected future conditions related to 
trapping/harvesting, climate change, or other potential cumulative 
impacts (Service 2018, p. 73). Beyond this range, climate

[[Page 64633]]

modeling uncertainty increases substantially. We believe this is a 
reasonable timeframe to consider as it includes the potential for 
observing these effects over several generations of the wolverine.
    As discussed above in Analytical Framework, we consider what the 
species needs to maintain viability by characterizing the status of the 
species in terms of resiliency, redundancy, and representation (Wolf et 
al. 2015, entire). Resiliency is having sufficiently large populations 
for the species to withstand stochastic events (arising from random 
factors). We can measure resiliency based on metrics of population 
health; for example, birth versus death rates and population size. 
Resilient populations are better able to withstand disturbances such as 
random fluctuations in birth rates (demographic stochasticity), 
variations in rainfall (environmental stochasticity), or the effects of 
anthropogenic activities.
    Redundancy is having a sufficient number of populations for the 
species to withstand catastrophic events (such as a rare destructive 
natural event or episode involving many populations). Redundancy is 
about spreading the risk and can be measured through the duplication 
and distribution of populations across the range of the species. The 
greater the number of populations a species has distributed over a 
larger landscape, the better it can withstand catastrophic events.
    Representation is having the breadth of genetic makeup of the 
species to adapt to changing environmental conditions. Representation 
can be measured through the genetic diversity within and among 
populations and the ecological diversity (also called environmental 
variation or diversity) of populations across the species' range. The 
more representation, or diversity, a species has, the more it is 
capable of adapting to changes (natural or human caused) in its 
environment. In the absence of species-specific genetic and ecological 
diversity information, we evaluate representation based on the extent 
and variability of habitat characteristics within the geographical 
range.

Life-History Needs

    Wolverines are capable of moving and dispersing over great 
distances over short periods of time. Wolverine populations are 
characterized by naturally low densities in North America. The species 
is highly territorial, with very little overlap between same-sex 
adults. Wolverines occupy a variety of habitats, but generally select 
habitat in locations away from human settlements. Wolverines consume a 
variety of food resources, and seasonal switching of prey is commonly 
observed. As with other Arctic mammals, wolverines have the ability to 
adapt to both warm and cold ambient temperatures and solar radiation 
through both physiological and behavioral responses, such as 
vasodilation, increase in skin temperature, seasonal adjustments in fur 
insulation, and micro- and macro-habitat selection.
    Wolverine reproduction includes the following characteristics: 
polygamous behavior (i.e., male mates with more than one female each 
year), delayed implantation (up to 6 months), a short gestation period 
(30-40 days), denning behavior, and an extended period of maternal 
care. The reproductive behavior in wolverines is temporally adapted to 
take advantage of the availability of food resources, limited 
interspecific competition, and snow cover in the winter.
    Since the publication of the Service's 2013 proposed rule to list 
the distinct population segment of the North American wolverine in the 
contiguous United States (78 FR 7864; February 4, 2013), several new 
wolverine studies have been published (e.g., Aronsson 2017, Aronsson 
and Persson 2016, Aronsson et al. 2017, Heinemeyer et al. 2019, Jokinen 
et al, 2019, Magoun et al. 2017, Persson et al. 2017, Stewart et al. 
2016, Webb et al. 2016, see additional list of citations in the 
wolverine SSA report). These studies have improved our understanding of 
wolverine biology while also highlighting new insights into identifying 
key species' needs and their interactions with both abiotic and biotic 
factors. Of particular importance relative to life history needs and 
wolverine reproductive behavior, wolverine populations and wolverine 
dens have been observed outside previously modeled projections of 
spring snow cover.
    Overall, the best available information indicates that within the 
contiguous United States the wolverine's physical and ecological needs 
include:
    (1) Large territories in relatively inaccessible landscapes, at 
high elevation (1,800 to 3,500 m (5,906 to 11,483 ft));
    (2) access to a variety of food resources, which vary with seasons; 
and
    (3) physical/structural features (e.g., talus slopes, rugged 
terrain) linked to reproductive behavioral patterns.

Current Condition

Current Potential Extent of Occurrence
    As noted above, using the best available information on current 
distribution and recent occurrences, we created maps to describe an 
area of ``current potential extent of occurrence'' (current potential 
extent) of wolverine for the western-northwestern contiguous United 
States (Service 2018, pp. 12-13, 15). The current potential extent 
represents the perimeter of the outermost geographic limits based on 
all (available) occurrence records (that is, the maximum extent of 
occurrences) for the wolverine minus those areas where we believe the 
species has been extirpated (Service 2018, pp. 11-12). The current 
potential extent area identified in Figure 2 encompasses approximately 
280,316 km\2\ (69,267,592 acres (ac)) (Service 2018, p. 12). We also 
prepared a current potential extent map for all of North America, 
including Canada and Alaska, for a total estimated current potential 
extent of 8,114,878 km\2\ (2,005,230,024 ac) (Service 2018, p. 12 and 
Figure 1 of this document). The current potential extent area in the 
contiguous United States represents approximately 3.5 percent of the 
total current potential extent of wolverines in North America (Service 
2018, p. 13 and Figure 2 of this document).
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Population Abundance and Density
    Areas in the western contiguous United States have been previously 
identified as suitable for wolverine survival (long-term survival; used 
by resident adults) or primary habitat, reproduction (used by 
reproductive females), and dispersal (female and male) of wolverines 
(see methodology in Inman et al. 2013, pp. 279-280). From these 
results, the researchers estimated potential and current distribution 
and abundance of wolverines in the western contiguous United States. 
They estimated current population size of wolverines to be 318 
individuals (range 249-626) located within the Northern Continental 
Divide (Montana) and areas within the following ecoregions: Salmon-
Selway (Idaho, portion of eastern Oregon), Central Linkage (primarily 
Idaho, Montana), Greater Yellowstone (Montana, Idaho, Wyoming), and 
Northern Cascades (Washington) (Inman et al. 2013, p. 282). Potential 
wolverine population capacity based on habitat modeling was estimated 
to be 644 individuals (range: 506-1,881) (Inman et al. 2013, p. 282); 
however, we do not have information indicating wolverine abundance in 
the contiguous United States.
    In the wolverine SSA report, we provide a discussion of recent 
studies of wolverine detections and observations in the western United 
States (Service 2018, pp. 51-56); however, no comprehensive surveys 
have been conducted across the entire area defined as the species' 
maximum extent of occurrence (Service 2018, p. 14; Figure 2) or current 
potential extent of occurrence (Figure 2 above) in the contiguous 
United States. Below we

[[Page 64635]]

provide a summary of recent wolverine observations and detections in 
the western United States.
    A recent study (2007-2015) has demonstrated that the Cascades 
region of Washington and Canada supports a resident wolverine 
population (Aubry et al. 2016, p. 40). For the first time in recent 
history, a breeding female wolverine was detected south of I-90 in the 
south Cascades of Washington, as well as her potential mate, indicating 
wolverines may be extending their current range in that area (Flatt 
2018, p. 1). Wolverines have been detected in the Eagle Cap Wilderness 
Area in the Wallowa Mountains of northeastern Oregon in 2011-2012, 
2016, and 2017 (Magoun et al. 2013, p. 17; Magoun 2017, pers. comm.). 
In California, a single male wolverine occurs in the Truckee area as of 
March 2017 (Shufelberger 2017, pers. comm.).
    Since 2010, survey and monitoring efforts in the Idaho Panhandle 
and adjoining areas of Washington, Montana, and British Columbia, 
Canada, have detected five individual male wolverines (Service 2018, p. 
52). One male was also detected in British Columbia, north of Canadian 
Highway 3 (Lucid et al. 2016, p. 184), which some consider to be a 
barrier to wildlife passage (IDFG 2017, pers. comm.). This male was 
most recently detected in Idaho, on March 6, 2013 (Lucid et al. 2016, 
p. 175). One likely wolverine den was located in the Saint Joe 
Mountains in Idaho (Lucid et al. 2017, p. 12).
    Results from a pilot study to evaluate wolverine occupancy in 
Wyoming indicated at least three individual wolverines (at five 
stations) with at least one individual in the Gros Ventre and Wind 
River mountain ranges, and at least two individuals in the Southern 
Absaroka mountain range (Inman et al. 2015, p. 9). Occupancy modeling 
estimated a probability of occupancy for sampled sites of 62.9 percent 
(Inman et al. 2015, p. 8).
    Building on the results of the Wyoming pilot study, the Western 
Association of Fish and Wildlife Agencies (WAFWA), in coordination with 
Tribal partners, formed a multi-State, multi-agency working group 
(Western States Wolverine Working Group) to design and implement the 
Western States Wolverine Conservation Project (WSWCP)-Coordinated 
Occupancy Survey. The primary objectives of the WSWCP include: (1) 
Implement a monitoring program to define a baseline wolverine 
distribution and genetic characteristics of the metapopulation across 
Montana, Idaho, Wyoming, and Washington; (2) model and maintain the 
connectivity of the wolverine metapopulation in the western United 
States; and (3) develop policies to address socio-political needs to 
assist wolverine population expansion as a conservation tool, including 
translocation of wolverines (IDFG 2016, pers. comm.; Montana FWP 2016, 
pers. comm.; WGFD 2016, pers. comm.).
    The Wyoming Game and Fish Department began implementation of the 
survey in Wyoming in the Greater Yellowstone Ecosystem region and the 
Bighorn Mountains in the winter of 2015-2016 (WGFD 2016, pers. comm.). 
That initial survey detected at least three unique wolverines in the 
Wind River and southern Absaroka Mountain Ranges (WGFD 2016, pers. 
comm.).
    The monitoring effort was expanded in the winter of 2016-2017 in 
four States (Washington, Idaho, Montana, and Wyoming), and our review 
of the results indicate that wolverines were detected in all four 
States (Service 2018, p. 53). From this study, a total of 43 unique 
individuals were identified, 20 males and 23 females (Pilgrim et al. 
2018, no page number).
    We also received additional wolverine observations from State and 
Federal agencies in northwestern Wyoming. A wolverine was detected by 
camera in northern Grand Teton National Park, and a member of the 
public reported wolverine tracks in southwestern Grand Teton National 
Park while skiing, which was confirmed by a Forest Service biologist 
(Service 2018, p. 53). Both of these observations occurred in March 
2017. South of this area in the Wyoming Range (about 4 miles east of 
Alpine, Wyoming), a wolverine was detected by camera in May 2017 
(Service 2018, p. 53).
    Wolverine densities vary across North America and have been 
described as naturally low and wolverine populations as naturally 
uncommon given the species' large home range, wide-ranging movements, 
and solitary characteristics (Service 2018, p. 56). In the contiguous 
United States, density estimates (number of wolverines per 1,000 km\2\ 
(386 mi\2\)) ranged from 3.5 for the Greater Yellowstone region (2001-
2008) (areas above 2,150 m (7,054 ft) (latitude-adjusted elevation), 
4.5 for central Idaho (1992-1995), to 15.4 for northwestern Montana 
(1972-1977) (Service 2018, p. 57).
    We note here that in our 2013 proposed listing rule for the 
wolverine (78 FR 7864), we discussed the occurrences of two dispersing 
individuals in California and Colorado (the Colorado wolverine was 
later killed in North Dakota). We know of one male wolverine in 
California that has consistently occupied an area much farther north in 
the Sierra Nevada Mountains, and we have no evidence of any other 
wolverines currently in the State. We have no recent records of 
wolverines in Arizona. Aubry et al. (2007, p. 2,150) identified the 
year 1860 as the most recent verifiable documentation of wolverines in 
northern New Mexico. We know of no wolverines currently occupying 
Colorado. As presented in Aubrey et al. (2007, p. 2,151; Figure 1), 
prior to 1900, the most recent verifiable record for wolverine in New 
Mexico was 1860 and 1887 for Nebraska; no records were found for 
Arizona, Texas, Oklahoma. This was also true for most midwestern and 
mid-Atlantic States (Aubrey et al., 2007, p. 2,152, Figure 1). 
Additionally, historical range maps shown in Seton (1909, p. 947; Map 
51), Aubrey et al. (2007, p. 2,152; Figure 1), and the assessment and 
status review for the wolverine in Canada (COSEWIC 2014, p. 12; Figure 
3) do not extend the distribution of wolverines into these regions.
    Our updated analysis of wolverine occurrence in the contiguous 
Unted States is based on a more scientifically robust and spatially 
explicit assessment of the current areas occupied by wolverines in the 
contiguous United States, which was prepared based on verifiable 
wolverine records and comments received by reviewers of a draft of the 
wolverine SSA report (see the Historical Range and Distribution section 
of the wolverine SSA report for more on the information used to assess 
the maximum extent of occurrences (`historical range') and current 
extent of occurrence (Service 2018, pp. 9-16; Figures 2-4)). Using the 
current potential extent of occurrence, as presented in Figures 1 and 2 
above, provides a more accurate reflection of the areas currently 
occupied by wolverines in the contiguous United States supported by the 
best available information.
Alaska and Canada
    In the wolverine SSA report, we provide a summary of population 
abundance in Alaska and Canada where wolverines are more abundant than 
in the contiguous United States (Service 2018, pp. 57-60). Much of what 
we know about wolverine occurrences and abundance has been gathered 
from trapping records (see summary in Service 2018, pp. 53-56).
    In Alaska and Yukon, density estimates presented by Inman et al. 
(2012, p. 789) range from 3 to about 14 wolverines per 1,000 km\2\ (386 
mi\2\), using a number of methods. For

[[Page 64636]]

example, Royle et al. (2011, p. 609) estimated wolverine densities for 
southeastern Alaska (Tongass National Forest; 2008) from 8.2 to 9.7 per 
1,000 km\2\ (386 mi\2\) (using mark-recapture), where the higher 
estimate incorporates a positive, trap-specific behavioral response. 
Density of wolverines were recently reported as an estimated 5-10 
wolverines per 1,000 km\2\ (386 mi\2\) (based on snow tracking) for 
southcentral Alaska, and approximately 10 per 1,000 km\2\ (386 mi\2\) 
(based on DNA mark-recapture methods) for southeastern Alaska (Golden 
2017, pers. comm.). A wolverine occupancy study in 2015 within an area 
of central Alaska reported a density estimate of 9.48 wolverines per 
1,000 km\2\ (386 mi\2\) (Alaska Department of Fish and Game (ADF&G) 
2015, p. 7).
    Wolverine density estimates for Canada vary across regions, from 5 
to 10 per 1,000 km\2\ (386 mi\2\) in northern mountain and boreal 
regions to 1 to 4 per 1,000 km\2\ (386 mi\2\) in southern boreal areas 
(COSEWIC 2014, p. 27). More recently, Clevenger et al. (2017, entire) 
presented a density estimate (using spatial capture/recapture models) 
for the Kootenay region of British Columbia of 0.78 wolverines per 
1,000 km\2\ (386 mi\2\), for 3 study years (2014-2016), which they 
reported as lower than expected (Clevenger et al. 2017, p. 6). 
Researchers in Canada are currently conducting a landscape level 
analysis to estimate the size and sustainable harvest for wolverine 
populations within British Columbia (Weir 2017, pers. comm.).
    According to the most recent COSEWIC Assessment and Status Report 
on the Wolverine, Gulo gulo in Canada (COSEWIC 2014, entire), Canada's 
western subpopulation has been estimated at 15,688 to 23,830 adults, 
which we recognize is an estimate based on several assumptions, such as 
consistent trapping effort and uniform densities across the species' 
range (COSEWIC 2014, p. 36). In Alaska, estimates of populations are 
not available and are best evaluated based on density with recent 
density estimates ranging from 5 to 10 wolverines per 1,000 km\2\ (386 
mi\2\) for Alaska (Parr 2017, pers. comm.). In Alaska, which, like 
Canada, allows regulated hunting and trapping of wolverines, an average 
of 590 wolverines have been taken each year over the past 6 years 
(Service 2018, p. 68). The consistent harvest levels in these regions 
suggest relatively stable wolverine populations in Alaska that more 
likely than not number in the thousands of individuals in order to 
sustain such level of harvest.
    We do not have reliable current population estimates for wolverines 
in the contiguous United States. As discussed above, the only estimate 
available is from 2013, when researchers, using spatial modeling 
methods, estimated the then-current population size of wolverines to be 
318 (range: 249-626) (Inman et al. 2013, p. 282). Potential wolverine 
population capacity in the contiguous United States based on habitat 
modeling was estimated to be 644 individuals (range: 506-1,881) (Inman 
et al. 2013, p. 282). However, these capacity estimates did not 
consider spatial characteristics related to behavior, such as 
territoriality (home range), of wolverine populations. Given all the 
assumptions, differing methods of estimation, limitations, and 
uncertainties of the available estimates of North American wolverines 
(as discussed in the wolverine SSA report (Service 2018, pp. 50-56)), 
we believe caution should be used relative to comparing the number of 
wolverines in the contiguous United States to the remainder of the 
taxon. However, even assuming the high population estimate from 2013 
for the contiguous United States (n=626) and the low estimate of 
wolverines in western Canada from 2014 (15,688 adults), the contiguous 
United States conservatively contains approximately 4 percent of the 
total wolverines within these two regions. This estimate does not 
account for wolverines in Alaska, for which we have no population 
estimate, but, based on a rough estimate of land area for the State 
occupied by wolverines and estimated wolverine densities of between 5 
to 10 animals per 1000 km\2\ (386 mi\2\) (Parr 2017, pers. comm.), it 
is reasonable to assume there are thousands of wolverines in the State. 
The actual percentage of wolverines in the contiguous United States 
compared to the overall taxon (Canada and Alaska included) is still 
significantly less than 4 percent of the overall North American 
wolverine population. Wolverine densities vary across North America and 
have been described as being naturally low, due in large part to the 
species having large home ranges, wide-ranging movements, and solitary 
characteristics (Service 2018, p. 56). It is important to understand 
that the amount of suitable habitat in the contiguous United States 
identified both in historical and current distribution maps (see, for 
example, 1909, p. 947; Map 51), Aubrey et al. (2007, p. 2,152) does not 
support the larger numbers of wolverines and higher densities found in 
Canada and Alaska (see Figure 3 in the wolverine SSA report (Service 
2018, p. 15)).
    Summary of Factors Affecting the North American Wolverine
    As mentioned above in Regulatory Framework, a species may be 
determined to be an endangered or threatened species due to one or more 
of the five factors described in section 4(a)(1) of the Act: (A) The 
present or threatened destruction, modification, or curtailment of its 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence. Listing actions may 
be warranted based on any of the above threat factors, singly or in 
combination. Potential stressors evaluated for wolverine in the 
contiguous United States include effects from roads (Factors A and E); 
disturbance due to winter recreational activity (Factors A and E); 
other human disturbance (Factors A and E); effects from wildland fire 
(Factor A); disease (Factor C); predation (Factor C); overutilization 
(trapping) (Factor B); genetic diversity (Factor E); small-population 
effects (Factor E); and climate change (Factors A and E). A summary of 
the potential stressors affecting wolverine in the contiguous United 
States is presented below; for a full description of our evaluation of 
the effects of these stressors, refer to the wolverine SSA report 
(Service 2018, pp. 57-101).
    Effects from Roads: Wolverines are associated with habitat found in 
high-elevation areas, but are known to disperse over great distances. 
Major highways can present mortality risks to dispersing individuals 
and affect immigration to open territories, but roads do not represent 
absolute barriers to wolverine movements. Wolverines den during winter 
months in locations that are often inaccessible or restricted to 
motorized vehicles, though secondary roads and trails are used for 
winter recreational activity. Although we recognize there are likely 
additional events that have not been reported, we estimated the total 
number of wolverine mortalities due to roads from 1972 to 2016 (44 
years) in North America was 20, at least 11 of which are from Canada 
(Service 2018, p. 60). In the SSA report, we calculated a low 
proportion of major highways in both modeled primary habitat and a low 
mean density of roads at high elevations where wolverines have been 
observed, with the exception of the southern Rocky Mountains (Service 
2018, p. 60). We therefore determine that the effects from roads 
present a low stressor to wolverines at the individual and population 
level in

[[Page 64637]]

most of its current area of occupancy within the contiguous United 
States.
    Disturbance due to Winter Recreational Activity: Wolverine behavior 
patterns, such as denning, rearing of young, movement and dispersal, 
and foraging/scavenging, may be affected by recreational activities 
(COSEWIC 2014, p. 42), although several wolverines have been captured 
for research on or near ski areas (e.g., Teton Mountains) (Montana FWP 
2017, pers. comm.). In Norway, one study found, at the home-range 
scale, a minimal threshold distance of approximately 1.5 km (0.93 mi) 
for wolverine den sites from private roads and/or recreational cabins 
(May et al. 2012, p. 201). Another study found that in an area of 
active recreation (Columbia Mountains, Canada), female wolverines were 
negatively associated with helicopter and backcountry skiing in their 
winter models (Krebs et al. 2007, pp. 2,187-2,188). In summer months, 
Copeland et al. (2007, p. 2,210) reported that wolverines in their 
study area of central Idaho were not uncommonly found near maintained 
trails and active campgrounds, which suggests some level of tolerance 
to human presence/recreational activity.
    The Wolverine-Winter Recreation Study represents an ongoing project 
to evaluate the potential effects of backcountry winter recreation 
(e.g., backcountry skiers, heli-skiers, cat-skiers, snowmobilers) on 
wolverines in central Idaho and areas in the western Yellowstone region 
(Island Park area and Teton Mountains) (Heinemeyer 2016, pers. comm.; 
Heinemeyer 2019, entire; Heinemeyer and Squires 2015, p. 3). Early 
analysis of the data suggested that wolverines demonstrate a behavioral 
response to recreation activities, such as increased movement rates and 
a reduction in resting periods in areas of high-recreation activity, 
especially high-recreation days (Saturday and Sunday) (Heinemeyer and 
Squires 2013, pp. 5, 7-8). However, this research also found that 
wolverines maintained their home ranges within areas with relatively 
high winter-recreation activity over several years of monitoring, 
including some areas found to contain the highest recreational 
activities (Heinemeyer 2016, pers. comm.). The study has not been able 
to determine whether these resident wolverines are reproductively 
successful due to the limited monitoring information available for 
reproductive females (Heinemeyer 2016, pers. comm.).
    A final Winter Recreation Study report found that wolverines 
maintained multi-year home ranges in areas that support relatively 
intensive winter recreation, suggesting that wolverines are able to 
tolerate winter recreation at some scales (Heinemeyer et al. 2017, p. 
iv; Heinemeyer et al. 2019, p. 16). Wolverines responded negatively to 
increasing intensity of winter recreation, with off-road and dispersed 
recreation having a greater effect than recreation that was 
concentrated on access routes (Heinemeyer et al. 2017, p. 34; 
Heinemeyer et al. 2019, p. 13). Wolverine avoidance of roads and 
groomed areas used by winter recreationists was found to be less than 
estimated for dispersed recreation, suggesting that wolverines may be 
less sensitive to predictable winter-recreational use patterns 
(Heinemeyer et al. 2017, p. 40; Heinemeyer et al. 2019, p. 15). Habitat 
selection in females evaluated in the multi-year study was complex, and 
likely driven by a combination of abiotic (snow, cold) and biotic 
factors (predator avoidance, food availability) (Heinemeyer et al. 
2017, p. 36; Heinemeyer et al. 2019, p. 16). This study did not assess 
demographic effects, fitness effects, or population level effects of 
winter recreation on wolverines (Heinemeyer et al. 2019, p. 17 and 19).
    Conservation measures currently being implemented that address the 
effects of roads in the Teton Mountains include winter closures in 
certain areas (generally from November 1 through May 1), including road 
closures in the Bridger-Teton and Caribou-Targhee National Forests and 
in Grand Teton National Park (Service 2018, p. 67, Appendix F). These 
closures are being implemented to help minimize disturbance to wildlife 
(e.g., migration pathways). State Wildlife Action Plans prepared for 
individual western States identify recreation management strategies 
within wolverine habitats. For example, in Oregon, the Oregon 
Department of Fish and Wildlife Conservation Strategy identifies 
management of winter-recreation use as a conservation action to avoid 
impacts to wolverines (ODFW 2016). In Montana's State Wildlife Action 
Plan, conservation actions for the wolverine are identified to address 
potential impacts from recreation, such as consideration of seasonal 
closures during denning season (Montana FWP 2015, p. 63). The Idaho 
Department of Fish and Game Management Plan for the Conservation of 
Wolverines in Idaho also includes conservation strategies related to 
developing a better understanding of the relationships between 
wolverine behavior and winter recreation activities (IDFG 2014, p. 35), 
and the State continues to support the Wolverine-Winter Recreation 
Study. Appendix G in the SSA report provides additional details on 
individual State conservation strategies. Although we do not rely on 
these conservation measures to support our decision on listing status, 
they do provide some protections to address potential impacts to 
wolverine from disturbance from winter recreational activity and 
mortality from roads.
    Based on the studies summarized above, wolverine behavior 
(movement) is potentially affected by winter recreational activity. 
However, wolverines can maintain residency in high winter-recreational 
use areas (Heinemeyer et al. 2017, p. iv; Heinemeyer et al. 2019, p. 
16). Based on the best available scientific and commercial information, 
the effect of winter recreational activity represents a low stressor to 
wolverines in the contiguous United States at the individual and 
population level.
    Other Human Disturbance: Infrastructure, such as pipelines, active 
logging or clearcuts, seismic lines, and activities associated with 
mining (e.g., producing mines, mines under development, mineral 
exploration areas), may also affect individual wolverine behavior 
(e.g., avoidance) or loss or modification of wolverine habitat. In the 
SSA report, we summarize a recently published study of habitat 
selection of wolverines in response to human disturbance in western 
Canadian forested habitat (Service 2018, p. 62). That study found that 
wolverines avoided interior areas of some logged areas, but also found 
that wolverines were attracted to all-season road sections with borrow 
pits (Scrafford et al. 2017, pp. 32-34). The authors concluded that 
wolverine selection patterns relative to industrial activity and 
infrastructure in their study area represented a balance between 
exposure to predators and foraging opportunities (Scrafford et al. 
2017, p. 32). Based on the best available scientific and commercial 
information, we find that these human disturbance effects are likely to 
be small or narrow in scope and scale for wolverines in the contiguous 
United States.
    Effects from Wildland Fire: Wildland fire can produce both direct 
and indirect effects to wildlife. Direct effects include injury and 
mortality as well as escape or emigration movement away from fires 
(Lyon et al. 2000, pp. 17-21). We are unaware of any studies evaluating 
direct effects of wildland fire to wolverines. Wildland fire is likely 
to temporarily displace wolverines, which could affect home range 
dynamics. Given that

[[Page 64638]]

wolverines can travel long distances in a short period of time, 
individuals would be expected to move away from fire and smoke 
(Luensmann 2008, p. 14). In addition, because young wolverines are born 
in underground or otherwise sheltered dens during winter months and in 
locations where wildland fire risk is low due to snow cover or 
increased moisture (Luensmann 2008, p. 14), the potential effects of 
fire at that critical life stage is very low (Luensmann 2008, p. 14). 
Indirect effects of wildland fire can include habitat-related effects 
or effects to prey and competitors/predators; however, we are unaware 
of empirical studies evaluating these potential effects as they relate 
to wolverines.
    Given the diversity of habitats occupied by wolverines, their 
opportunistic foraging habitats and seasonal switching of food sources, 
their occupancy of high elevations, and extensive mobility, wildland 
fire represents a limited indirect and direct stressor, in scope and 
scale, to wolverine habitat and its prey in the contiguous United 
States range (Service 2018, pp. 63-64) such that it would not be 
expected to have population or species-level impacts.
    Disease: We are unaware of comprehensive surveys evaluating the 
prevalence of diseases in wolverines in the contiguous United States. 
Other than a parasitic pneumonia mortality event and a single rabies 
case, we are not aware of any other studies documenting impacts of 
disease to wolverines in North America (Service 2018, p. 65). At this 
time, based on the best available scientific and commercial 
information, we do not find that disease is a population- or species-
level stressor to the wolverine in the contiguous United States 
(Service 2018, pp. 64-65).
    Predation: A number of potential natural predators have been 
identified for wolverines within its North American range, including 
intraspecific predation (Service 2018, p. 65). However, we have no 
information that suggests predation represents a significant stressor 
to the wolverine at the population level. At the individual level, we 
recognize that wolverines likely avoid areas of potential predation 
risk from wolves and other potential predators (Service 2018, p. 65). 
Thus, indirect effects of predators may result in predator avoidance 
behavior of individual wolverines through habitat selection. However, 
the best scientific and commercial information available indicates that 
predation is not a stressor for the wolverine (Service 2018, p. 65).
    Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes: During the late 1800s and early 1900s, the 
wolverine population declined or was extirpated in much of the 
contiguous United States, which has been attributed in large part to 
unregulated persecution (Service 2018, p. 1). Similar range reductions 
and extirpations of some wolverine populations were observed in parts 
of Canada during this time period (van Zyll de Jong 1975, entire; 
COSEWIC 2014, p. iv). However, after unregulated harvest of wolverines 
ceased, the numbers of wolverines in Canada and the contiguous United 
States began to recover from this decline (e.g., Aubry et al., 2007, p. 
2,151; Aubry et al., 2012, entire; Aubry et al. 2016, pp. 14-15; Magoun 
et al. 2013, p. 27).
    In Montana, wolverines were a legally harvested furbearer up until 
2012 (Service 2018, p. 65). There is, however, no evidence to suggest 
that the harvest of wolverines in Montana at historical rates (about 10 
animals per year) was detrimental to wolverine populations (Service 
2018, pap. 65-66 and Appendix G). Furthermore, States within the 
wolverine range in the contiguous United States have adopted protective 
regulations to prevent unauthorized take and are implementing other 
measures to limit incidental mortality of wolverines (Service 2018, p. 
66). There is currently no allowable trapping or harvesting of 
wolverines in the contiguous United States, although incidental 
trapping, shooting, and poisoning mortalities have been documented 
(Service 2018, pp. 65-69).
    In Alaska, wolverine trapping and hunting is controlled by seasons 
and bag limits, with about 550 animals harvested each year (ADF&G 
2017a). This level of harvest has been fairly consistent since 2010 
(Service 2018, Table 7).
    Trapping and harvesting of wolverines occurs over much of the range 
in Canada (COSEWIC 2014, pp. 10, 29-35). Specifically, wolverines are 
harvested in the northern and western territories--Manitoba, 
Saskatchewan, Alberta, British Columbia, Yukon, Northwest Territories, 
and Nunavut (COSEWIC 2014, p. 43). The population of wolverines in 
British Columbia is estimated to be 2,700-4,760 and 1,500-2,000 animals 
in Alberta (COSEWIC 2014, p. 36). In the wolverine SSA report, we 
evaluated trapping of wolverines in British Columbia and Alberta 
regions of southern Canada in an effort to document potential impacts 
to dispersing wolverines along the U.S.-Canada border (Service 2018, 
pp. 68-69). This type of analysis was not conducted for the 2013 
proposed listing rule (78 FR 7864; February 4, 2013) or for our 2014 
withdrawal (79 FR 47522; August 13, 2014). The results of our spatial 
analysis for British Columbia indicates a total of 77 wolverines were 
trapped in wildlife management units within 110 km (68.35 mi) of the 
U.S.-Canada border in the period 2007-2015, or an average of 8.5 
animals per year (Service 2018, pp. 68-69). We used this distance since 
it is similar to both the average maximum distance per dispersal 
movement of 102 km (63 mi) for male wolverines in the Greater 
Yellowstone region of Montana (Inman et al. 2012, p. 784), and a 
reported 100-km (62-mi) dispersal distance for a juvenile male for 
Ontario, Canada (COSEWIC 2014, p. 24, citing unpublished data from 
Dawson et al. 2013). For Alberta, we identified a total of 15 
wolverines harvested by trappers and data presented in other studies 
within 110 km (68.35 mi) of the U.S.--Canada border in the period 1989-
2014 (average of less than 1.0 animal per year) (Service 2018, p. 68).
    Based on this new analysis, legal trapping effort along the U.S.-
Canada border does not represent a barrier to wolverine movement and 
dispersal along the international border. As discussed below and in the 
DPS analysis above, results from genetic analyses provide further 
evidence of movement and dispersal of wolverines across the 
international border (see Genetic Diversity below).
    In summary, overutilization does not currently represent a stressor 
to the wolverine in the contiguous United States at the individual, 
population, or species level. Wolverine populations in the contiguous 
United States are currently protected under several State laws and 
regulations. Regulated hunting and trapping activities for wolverines 
are currently suspended or closed entirely for animals that occupy 
western States of the contiguous United States, though occasional 
incidental trapping can occur. Current trapping in Alaska and Canada 
appears to be sustainable and wolverine populations along the Alaska--
Canada border are continuous with the Yukon region of Canada, which 
suggests a rescue effect (animals from a higher population density area 
moving to areas of lower population density, preventing local 
extirpation) for Canadian populations along this international boundary 
(COSEWIC 2014, p. 37). Trapping or harvesting of wolverines along the 
contiguous U.S.-Canada border does not represent a barrier or stressor 
to wolverines migrating into the contiguous United States at the 
individual or population level.

[[Page 64639]]

    Genetic Diversity: The geographical genetic structure of wolverines 
is believed to be largely structured around the strong female 
philopatry characteristic of this species (Rico et al. 2015, p. 2) and 
the species' polygamous behavior. Results from Scandinavia indicate 
that wolverine population distributions are primarily limited by 
dispersal of the more philopatric sex (females) (Aronsson 2017, p. 13). 
The extensive and often asymmetrical movement of male wolverines from 
core populations to the periphery of their range can result in the 
addition of nuclear genetic material to these edges (Zigouris et al. 
2012, p. 1,553). Thus, the dispersal pattern for male wolverines may 
help explain why allelic richness (i.e., nuclear DNA, which is 
inherited from both parents) can be similar across regions, but 
haplotype richness (mitochondrial DNA, which is maternally inherited) 
is lower at the periphery of the species' range (Zigouris et al. 2012, 
p. 1,553).
    Studies evaluating the genetic structure of wolverines, primarily 
within its core range in North America, were presented in Chappell et 
al. (2004) and Kyle and Strobeck (2001, 2002). Using microsatellite 
markers, Kyle and Strobeck (2002) and Zigouris et al. (2012) found 
greater genetic structure of wolverines toward the eastern and southern 
peripheries of their North American distribution, likely due to a west-
to-east recolonization during the Holocene (Zigouris et al. 2013, p. 
9). Similarly, based on an evaluation of mitochondrial DNA, which is 
used primarily for an evaluation of phylogenetic structure and 
phylogeography, McKelvey et al. (2014, p. 330) concluded that modern 
wolverine populations in the contiguous United States are the result of 
recolonization (following persecution during a period of unregulated 
hunting or trapping and poisoning) from the north.
    Genetic diversity and population genetic structure of a larger 
sample size of wolverines were examined by Cegelski et al. (2006, 
entire) for the southern extent of their North American range using 
both microsatellite markers and mitochondrial DNA. They concluded that 
the wolverine populations in the contiguous United States were not 
sources for dispersing individuals into Canada (Cegelski et al. 2006, 
p. 208). They found that there was significant differentiation between 
most of the populations in Canada and the United States (Cegelski et 
al. 2006, p. 208). However, they cautioned that their statistical 
analysis may not have been able to detect ``effective migrants'' and 
that sample size can affect the detection of dispersers (Cegelski et 
al. 2006, p. 208). They concluded that some migration of wolverines was 
occurring between the Rocky Mountain Front region (northwestern 
Montana) and Canada as well as among wolverine populations in the 
United States, with the exception of Idaho (Cegelski et al. 2006, p. 
208).
    This study also conducted model simulations of the number of 
effective wolverine breeders necessary to maintain genetic variation 
(heterozygosity) in their sampled population of the contiguous United 
States in the absence of gene flow (Cegelksi et al. 2006, p. 201). They 
indicated that two effective migrants from either Canada or Wyoming 
into the Rocky Mountain Front population would be needed (per 
generation, 7.5 years) to maintain the levels of genetic diversity in 
that population, and one effective migrant was needed to maintain 
levels of diversity in the Gallatin, Crazybelt, or Idaho populations 
(Cegelski et al. 2006, p. 209). They also found that to maintain at 
least 95 percent of the genetic variation in the next 100 generations 
(we estimate this to be approximately 750 years, based on generation 
time) 200 to 300 wolverine breeding pairs were needed in the Wyoming 
and Rocky Mountain Front populations, respectively, and 200 breeding 
pairs were needed in the Gallatin, Crazybelts, and Idaho wolverine 
populations (Cegelski et al., 2006, pp. 208-209). The authors concluded 
that migration is essential for maintaining diversity in wolverine 
populations in the contiguous United States since effective population 
size may never be reached due to the naturally low population densities 
of wolverines (Cegelski et al. 2006, p. 209).
    More recently, an analysis of mitochondrial DNA was prepared for 
wolverine samples collected during the winters of 2015-2016 and 2016-
2017 as part of the Western States Wolverine Conservation Project-
Coordinated Occupancy provides further support that all contiguous 
United States historical (pre-1900) and recent wolverine populations 
are likely descendants of immigrants from Canada and suggest continued 
connectivity between the contiguous United States and Canadian 
wolverine populations (Pilgrim and Schwartz 2018, entire).
    Effective population size (Ne) is defined as ``the size 
of an idealized population that would experience the same amount of 
genetic drift and inbreeding as the population of interest. In popular 
terms, Ne is the number of individuals in a population that 
contribute offspring to the next generation'' (Hoffman et al. 2017, p. 
507; see also Service 2018, Box 2). It represents a metric for 
quantifying rates of inbreeding and genetic drift and is often used in 
conservation management to set genetic viability targets (Olsson et al. 
2017, p. 1). It is not the same as the more commonly used metric, 
census population size (N), but is often assumed to represent the 
genetically effective population size.
    In his review of the minimum viable population size concept, Ewens 
(1990, entire) emphasized that the term ``effective population size'' 
is not a meaningful term unless additional context is provided relative 
to which concept of population size is being evaluated (Ewens 1990, p. 
309). He introduced the concept of mutation effective population size, 
defined as the size of population defined by its capacity to maintain 
genetic variation (Ewens 1990, p. 307), which is different than actual 
population size (Ewens 1990, p. 309). Demographic factors such as sex 
ratio, subpopulations, dispersal, and immigration are needed when 
interpreting actual population size from an effective population size; 
thus, there is no justification for a fixed, genetically derived 
minimum viable population size value of `500' as each case is unique 
(Ewens 1990, p. 310). A review of the minimum viable population concept 
by Flather et al. (2011, entire) also found that any ``rule of thumb'' 
used for minimum viable population will likely be a poor estimate for 
that population (Flather et al. 2011, pp. 311, 313). Minimum viable 
population estimates therefore vary considerably both within and among 
species and are sensitive to the timeframe in which data are collected 
(Flather et al. 2011, p. 314).
    An effective population size analysis for wolverines in the 
contiguous United States was presented in Schwartz et al. (2009, p. 
3,225) using wolverine samples from the main part of the Rocky 
Mountains populations (e.g., central and eastern Idaho, Montana, 
northwestern Wyoming). Subpopulations from the Crazy and Belt Mountains 
in Montana were excluded from this analysis based on suggestion by 
Cegelski et al. (2003) that they represented separate groups (Schwartz 
et al. 2009, p. 3,225). The summed effective population size was 
estimated at 35, with credible limits from 28-52, and the summed values 
for the three timeframes was reported as follows: Ne 1989-
1994 = 33, credible limits 27-43; Ne 1995-2000 = 35, 
credible limits 28-57; Ne 2001-2006 = 38, credible limits 
33-59 (Schwartz et al. 2009, p. 3,226). Thus, the two later time-frames 
evaluated indicate an

[[Page 64640]]

(increasing) effective population size with credible limits above 50.
    Of direct relevance to potential gene flow and genetic structure at 
the landscape level, wolverines travel (disperse) through areas outside 
high-elevation, forested habitats. For example, tracked dispersal 
movements of a male wolverine, M56, from Wyoming into Colorado and its 
subsequent discovery in North Dakota, indicate extensive travel outside 
of modeled primary wolverine habitat (i.e., Inman et al. 2013), 
including through arid grasslands and shrubland habitats of the Wyoming 
Basin ecoregion (Packila et al. 2017, entire). This animal's movement 
also supports some level of connectivity (and gene flow) between 
currently occupied habitat (Wyoming) and unoccupied habitat within the 
wolverine's historic range (Colorado) (Packila et al. 2017, p. 404). 
Similarly, wolverines have recently moved from Washington and Idaho 
into British Columbia, and earlier from Montana to British Columbia and 
Alberta (Service 2018, p. 45). Based on genetic analyses, the male 
wolverine currently occupying an area within the Sierra Nevada 
Mountains of California also represents evidence of connectivity 
between wolverine populations of the Rocky and Sierra Nevada Mountain 
Ranges (Moriarty et al. 2009, p. 154). Wolverines have been detected 
making cross-valley movements in the Southwestern Crown of the 
Continent (SWCC) in northwestern Montana, which researchers believe is 
an indication of good connectivity in this region (SWCC Working Group 
2016, pers. comm.).
    It can be difficult to make inferences about the relationship 
between population size and point estimates of genetic diversity 
without continued genetic monitoring and an understanding of the 
demographic history of a species' population (Hoffman et al. 2017, p. 
507), including factors that have historically influenced and continue 
to influence movement patterns and connectivity. Additionally, the 
extensive dispersal movements of both male and female wolverines can 
produce gene flow among diverged populations, making it difficult to 
distinguish, without additional sampling and analysis, between long-
distance dispersal and fragmentation based on the patchy distribution 
of some haplotypes (Zigouris et al. 2013, p. 10). Genetic diversity can 
be a reflection of favorable adaptations (natural selection) and is 
necessary for species to locally adapt to environmental stressors or to 
facilitate range shifts (Zigouris et al. 2012, p. 1,544). Genetic 
distinctiveness in peripheral populations may therefore play a role in 
both maintaining and generating biological diversity for a species 
(Zigouris et al. 2012, p. 1,544; citing results presented in Channell 
and Lomolino 2000, p. 84). Relatedly, genetic variation that is 
adaptive is a better predictor of the long-term success of populations 
as compared to overall genetic variation (Hoffman et al. 2017, p. 510). 
The challenge is to be able to determine whether genetic variation is 
adaptive and is a reflection of remnants of high genetic diversity from 
ancestral populations, or whether that variation is a reflection of 
accumulated deleterious, nonadaptive genes due to genetic drift in 
small populations (Hoffman et al. 2017, p. 509).
    In summary, the currently known spatial distribution of genetic 
variability in wolverines in North America appears to be a reflection 
of a complex history where population abundance has fluctuated since 
the time of the last glaciation and insufficient time has passed since 
human persecution for a full recovery of wolverine densities (Cardinal 
2004, pp. 23-24; Zigouris et al. 2012, p. 1,554). Zigouris et al. 
(2012, p. 1,545) noted that the genetic diversity reported in Cegelski 
et al. (2006) and Kyle and Strobeck (2001, 2002) for the southwestern 
edge of the North American range represented only part of the diversity 
in the northern populations of wolverines. Zigouris et al. (2012, p. 
1,545) posit that the irregular distribution of wolverines in the 
southwestern periphery and the genetic diversity observed in those 
analyses is a result of population bottlenecks that were caused by 
range contractions from a panmictic (random mating) northern core 
population approximately 150 years ago coinciding with human 
persecution. As described here, recent dispersals of wolverines into 
Colorado, California, and Utah provide evidence for connectivity and 
the potential for gene flow between Northern Rocky Mountain populations 
and areas where wolverines were extirpated.
    As noted above in this section (and in the Distinct Population 
Segment section), there is recent evidence of wolverines traveling 
across the international border. Furthermore, our analysis of trapping 
levels in the wolverine SSA report (summarized in Overutilization for 
Commercial, Recreational, Scientific, or Educational Purposes above) 
does not support previous assumptions that trapping in Canada near the 
border acts as a barrier to wolverine movement into the contiguous 
United States. Cegelski et al. (2006, p. 209) determined that very few 
successful migrants are needed per generation to maintain at least 95 
percent of the genetic variation in the next 100 generations 
(approximately 750 years) in the contiguous United States (Cegelski et 
al. 2006, p. 209). We have no reason to believe that this level of 
migration from the north has not already been occurring following the 
end of intense persecution of this species to repopulate previously 
occupied areas within the contiguous United States. This repopulation 
has occurred without human-assisted introductions and with unregulated 
trapping from about the 1930s to 1970 in Montana. Given the recent 
observations of dispersing wolverines moving vast distances over varied 
terrain and movement of wolverines across the U.S.-Canada border, our 
recent assessment of the low levels of trapping mortality in Canada 
near the border, and further confirmation of Canada as the source of 
wolverine genetics present in contiguous United States wolverines, we 
conclude that wolverines in the contiguous United States are not 
separated genetically from the larger population in Canada. 
Furthermore, even if they were separated genetically, the multiple 
generations it would take for genetic isolation to potentially result 
in significantly lower genetic diversity and for the deleterious 
effects of decreased genetic diversity to then manifest into negative 
population-level effects is likely beyond the foreseeable future used 
for this determination (38 to 50 years, see Future Condition section 
below). As such, we conclude that loss of genetic diversity is not a 
stressor for wolverines in the contiguous United States now or within 
the foreseeable future.
    Small Population Effects: As described above in Population 
Abundance and Density, the number of wolverines in the contiguous 
United States is relatively small compared to the remainder of the 
range in Canada and Alaska, in large part due to limited suitable 
habitat and previous persecution and unregulated trapping pressures. As 
described above in Genetic Diversity, we now consider wolverines in the 
contiguous United States to be genetically connected to wolverines in 
Canada (McKelvey et al. 2014; Pilgrim and Schwartz 2018) and wolverines 
in the contiguous United States are not separated from the larger North 
American wolverine population to the North (Canada and Alaska). In 
previous proposed rules and findings, we have discussed small 
population

[[Page 64641]]

size as a vulnerability that places wolverines in the contiguous United 
States at risk of extirpation. However, those assertions were 
predicated on a belief that wolverines in the contiguous United States 
were effectively isolated regionally within the United States and 
isolated from Canada, thereby increasing the risk of deleterious 
genetic effects (countered above in Genetic Diversity) and 
susceptibility to stochastic events and limited rescue effect 
(migrants) from Canada. With further genetic evidence of the 
recolonization of once-extirpated areas of the contiguous United States 
by wolverines from Canada post-unregulated trapping over the last 
approximately 100 years, history has demonstrated the resiliency of the 
North American wolverine population to recover from extreme persecution 
and unprecedented direct mortality. We do not currently foresee any 
stochastic or catastrophic events that could result in a similar 
population-level effect on wolverines in the contiguous United States. 
It is no longer accurate to consider contiguous United States 
wolverines in isolation from the rest of North American wolverines; 
rather, it is more accurate to consider the contiguous United States 
wolverines a portion of a much larger and proven resilient North 
American wolverine population. We conclude that small population 
effects are not a stressor for wolverines in the contiguous United 
States now or within the foreseeable future.
    Climate Change: In the SSA report, included in our discussion of 
future conditions, we provide a summary of current trends related to 
observed climate change effects, such as increased temperatures and 
changes in precipitation patterns, in areas that encompass the current 
potential extent of occurrence for the wolverine. We are not aware of 
any adverse effects of these observed changes to the wolverine in the 
contiguous United States. The potential effects of future climate 
change (projections) are fully considered in our future condition 
analysis in the wolverine SSA report (Service 2018, pp. 73-99). We 
summarize the results of that analysis in the Future Condition section 
of this document below.
Summary of Current Condition
    Wolverine populations in much of North America are still recovering 
from large losses of individuals from intensive hunting and unregulated 
persecution pressures in the late 1880s into the mid-20th century 
(Service 2018, p. 104). The distribution of wolverines within suitable 
habitat provides a more appropriate method for estimating population 
status than using abundance of animals, although there is limited 
rangewide survey information. Based on the best available information, 
wolverines continue to be detected within suitable habitat within the 
western-northwestern contiguous United States including Washington, 
Oregon, Idaho, Montana, and Wyoming (Service 2018, p. 71). Studies are 
currently under way to provide a better assessment of the species' 
current distribution and genetic characteristics of these populations. 
The best available information does not indicate the portion of the 
North American wolverine population in the contiguous United States is 
currently negatively impacted by lower genetic diversity, and there is 
no evidence that wolverine numbers in the contiguous United States are 
declining.
    We prepared a map of the current potential extent of occurrence to 
illustrate the species' current distribution in the contiguous United 
States (Figure 2). We estimate this area represents approximately 3.5 
percent of the wolverine's current potential extent in North America 
(Service 2018, p. 71). We determined that 72 percent of our current 
potential extent of the wolverine in the contiguous United States is 
found on lands owned or managed by the Federal Government (Service 
2018, p. 72 and Appendix D). We also evaluated previously modeled 
wolverine primary habitat in the contiguous United States (Inman et al. 
2013, entire) and estimated that 96 percent of this area is owned or 
managed by Federal agencies and 41 percent of this area is located in 
designated wilderness areas (Service 2018, p. 72). In our SSA report, 
we provide a detailed summary of regulatory mechanisms and conservation 
measures affecting wolverines related to State and Federal land 
management in the contiguous United States (Service 2018, Appendix G).
    We evaluated several potential stressors that may be affecting 
wolverine populations or its habitat, including effects from roads, 
disturbance due to winter recreation and other activities, effects from 
wildland fire, disease and predation, overutilization for (primarily) 
commercial purposes, genetic diversity, and small-population effects.
    We determined that the effects of roads (evaluated by number of 
miles, density, and location) and disturbance represent low-level 
stressors to the wolverine in the contiguous United States. Wildland 
fire was determined to be a short-term stressor to wolverine habitat 
and its prey. Disease and predation, genetic diversity, and small 
population size are not considered stressors to the wolverine.
    Trapping or hunting of wolverines is currently prohibited in the 
contiguous United States. Incidental trapping of wolverines is 
infrequent in the contiguous United States and, in Idaho and Montana, 
education programs are being implemented to reduce this stressor. 
Wolverines are harvested in several Canadian provinces and near the 
U.S.-Canada border with management and monitoring oversight based on 
spatial and temporal elements. We evaluated historical trapping 
information to assess potential impacts to dispersing wolverines into 
the United States. Based on the best available commercial and 
scientific information, overutilization does not represent a stressor 
to the wolverine in the contiguous United States.
    We also determined that the wolverines in the contiguous United 
States are connected to and an extension of the Canadian population 
that is not genetically isolated nor considered a small population that 
may be more vulnerable to stressors.

Future Condition

    The foreseeable future timeframe evaluated in our SSA analysis is 
approximately 38 to 50 years, which captures consideration of the 
projected future conditions related to trapping/harvesting, climate 
change, or other potential cumulative impacts (Service 2018, p. 73). We 
use a timeframe of approximately 38 to 50 years because, beyond this 
range, climate modeling uncertainty increases substantially. We believe 
this is a reasonable timeframe to consider as it includes the potential 
for observing these effects over several generations of the wolverine. 
Evaluations of future conditions for species have an inherent level of 
uncertainty relative to demographic risks, particularly those related 
to climate change projections. After considering the current conditions 
for the wolverine and its habitat, we determine that climate change 
effects (i.e., significantly elevated temperatures resulting in decline 
in snowpack) that may modify suitable habitat, including reproductive 
denning habitat, could also change the scope of the wildland fire 
stressor and is the most likely future scenario to potentially have an 
effect on wolverines at the population level in the contiguous United 
States. Based on our review of the best available information, we 
determined that there were no other plausible future scenarios that 
were likely to have population-level impacts

[[Page 64642]]

to wolverine in the contiguous United States (Service 2018, p. 73). As 
described in detail in the wolverine SSA report (Service 2018, pp. 57-
72), the effects of disease, predation, overutilization (trapping), 
genetic diversity, small-population effects, and effects of wildland 
fire are expected to continue to be at low levels in the future but are 
not expected to result in population-level effects to wolverine.
Climate Change Effects
    In the wolverine SSA report, we considered climate changes that may 
affect environmental conditions upon which the wolverine relies. As 
defined by the Intergovernmental Panel on Climate Change (IPCC), the 
term ``climate'' refers to the mean and variability of different types 
of weather conditions over time (IPCC 2013, p. 1,450). Thus, the term 
``climate change'' refers to a change in the mean or the variability of 
relevant properties, which persists for an extended period, typically 
decades or longer, due to natural conditions (e.g., solar cycles) or 
human-caused changes in the composition of atmosphere or in land use 
(IPCC 2013a, p. 1,450).
    Multiple lines of evidence, not just projections derived from 
quantitative models, should be examined when conducting climate 
vulnerability assessments (Michalak et al. 2017, entire). Thus, we 
evaluated projected effects from climate change in the western United 
States relative to both abiotic (e.g., temperature, precipitation, snow 
cover) and biotic (e.g., phenology, behavior) factors. Refer to the 
wolverine SSA report for a complete discussion of our analysis of the 
effects of climate change to wolverine in the contiguous United States 
(Service 2018, pp. 73-99). We summarize the results of that analysis 
below.
Summary of Future Condition
    Abiotic Factors: Observed trends and future climate model 
projections indicate warming temperatures for much of the western 
United States, including areas within the current potential extent of 
the wolverine (Service 2018, pp. 75-81). The degree of future warming 
varies by region and is dependent upon the future emission scenario 
used during the modeling process. Future precipitation trends are less 
certain for many regions, in part, due to naturally high inter-annual 
variability; some regions are projected to experience greater winter 
precipitation (Service 2018, p. 81). Wolverines have been found to have 
a wide range in their physiological critical temperature depending on 
season and undergo seasonal changes in fur insulation to adapt to 
warmer temperatures in summer (Service 2018, p. 81). Wolverines also 
exhibit changes in behavior, such as moving to higher elevations in 
summer months (Service 2018, p. 81). Wolverines continue to occupy 
areas that have exhibited increases in temperature (e.g., California, 
parts of Montana and Washington) due to effects of climate change; 
however, no empirical studies have evaluated these physiological and 
behavioral adaptations, including sublethal effects, relative to 
warming temperatures (Service 2018, p. 81).
    Biotic Factors: In addition to evaluating changes in abiotic 
factors, biotic interactions should be considered in evaluating 
species' response to climate change (reviewed by Post 2013). Although 
abiotic changes drive ecological processes, the alterations in biotic 
interactions (e.g., competition among conspecifics, interactions with 
competitors, resources, and predators) represent the ecological 
responses that result from those changes (Post 2013, p. 1). Changes in 
certain abiotic factors, such as snow and ice cover, should also be 
considered in an ecological context since they represent habitat for 
many species (Post 2013, p. 11).
    The results presented in the wolverine SSA report indicate biotic 
effects resulting from climate change, varying from phenological 
changes to shifts in vegetation and vegetation succession (Service 
2018, pp. 81-82). We are unaware of studies that have directly 
evaluated these types of effects to the North American wolverine or its 
habitat. Given the relatively large area and varied habitats occupied 
by wolverines in the contiguous United States, the projected shifts in 
vegetation are likely to be relatively narrow in scope and scale 
relative to potential effects to wolverines. Furthermore, we have no 
information to suggest that wolverines selectively use any specific 
vegetation type, and some projected changes in vegetation may be 
advantageous for wolverine prey (Service 2018, p. 82).
Climate Change and Potential for Cumulative Effects
    Threats can work in concert with one another to cumulatively create 
conditions that may impact the wolverine or its habitat beyond the 
scope of each individual threat (Service 2018, p. 82). Given an 
expected increase in temperature in the western United States, the best 
available information indicates that, if there are any cumulative 
impacts in the future, the most likely population-level effects on 
wolverine in the contiguous United States could be: (1) Changes in 
snowpack from the combination of increased temperature and changes in 
precipitation patterns, or (2) changes in snowpack and increase in 
wildland fire potential (Service 2018, p. 83).
    Snowpack/Snow Cover: The effects of climate change on snow 
persistence has been suggested as an important negative impact on 
wolverine habitat and populations by the mid-21st century and was the 
primary basis of our 2013 proposed rule to list the North American 
wolverine in the contiguous United States (78 FR 7864; February 4, 
2013). In light of the court decision remanding our consideration of 
our withdrawal of the 2013 proposed rule relative to climate change 
effects to wolverine, the Service pursued a refined methodology to 
provide insights into the potential impacts of climate change on snow 
persistence (Service 2018, p. 85; Ray et al. 2017, entire).
    The Service engaged the National Oceanic and Atmospheric 
Administration and University of Colorado in Boulder, Colorado, to 
evaluate and model fine-scale persistence of snow in occupied and 
potential wolverine habitat in the contiguous United States. The 
primary objective of this study was to refine spatial and temporal 
scale of snow modeling efforts and improve the scientific understanding 
of the extent of spring snow retention currently and into the future 
under a changing climate (Ray et al. 2017, p. 9). The objectives of the 
study included (Ray et al. 2017, p. 10):
     Use of fine-scale models to analyze the topographic 
effects of snow, including slope and aspect (compass direction that 
slope faces).
     Use of a range of plausible future climate change 
scenarios to assess snow persistence.
     Analysis of extremes and year-to-year variability by 
selecting representative wet, dry, and near normal years (using 
observed conditions) and then modeling changes for those base years 
under several future climate scenarios.
     Assessment of changes in snow persistence by elevation.
    The study was designed to parallel as much as possible and thereby 
refine the previous assessment of snow cover persistence in the western 
United States presented in McKelvey et al. (2011). However, an exact 
replication of the McKelvey et al. (2011) study was not possible given 
the time, funding, and computational constraints needed to develop a 
fine-scale assessment. The current study was limited to two study

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areas (approximately 1,500 to 3,000 km \2\ (579 to 1,158 mi \2\) each) 
in the northern and southern Rocky Mountains (see Service 2018, 
Appendix H). These two National Parks bound the Northern and Southern 
part of the wolverine historic range, and were selected because they 
encompass the latitudinal and elevational range of wolverines within 
the contiguous United States. Glacier National Park is representative 
of a high-latitude and relatively low-elevation area currently occupied 
by wolverines. The Rocky Mountain National Park region is a lower 
latitude and higher elevation area within the wolverine's historical 
range, which was recently occupied by a wolverine from 2009 to at least 
2012. See the wolverine SSA report for a summary of the methods used in 
Ray et al. (2017) (Service 2018, pp. 86-87).
    Comparison with McKelvey et al. (2011): Although the methods used 
in this study have similarities with those presented in McKelvey et al. 
(2011), there are several key differences.
     Ray et al. (2017) used a finer spatial resolution model 
than McKelvey et al. (2011) (0.0625 km\2\ vs. 37 km\2\) (see Service 
2018, Appendix I for a comparison figure) that also incorporated slope 
and aspect.
     The grid cells represented in McKelvey et al. (2011) were 
assumed to be flat (i.e., north-facing slopes treated as identical to 
south-facing slopes).
     McKelvey et al. (2011) focused on May 1 snow depth as a 
proxy for May 15 snow disappearance, while Ray et al. (2017) focused 
directly on May 15 snow disappearance and produced results for the 
presence or absence of deeper snow (nominally greater than or equal to 
0.5 m (20 in) depth) on May 1 and April 15. Ray et al. (2017) 
originally focused on May 15 to compare to the McKelvey et al. (2011) 
study, and June 1 to bracket the snowmelt season. However, the April 15 
and April 30 dates were added to the evaluation of snow-covered areas 
to align with temporal reproductive patterns of the wolverine (see Use 
of Dens and Denning Behavior discussion in the Reproduction and Growth 
section of the wolverine SSA report (Service 2018, pp. 23-28)).
     Because of the increased resolution of this study, Ray et 
al. (2017) were able to consider whether any areas of snow with depth 
greater than 0.5 m (20 in) will persist in these areas in the future at 
time periods encompassing the end of the wolverine denning period. 
Additional comparisons are outlined in the wolverine SSA report 
(Service 2018, p. 88; Table 8) and our rationale supporting the use of 
snow depth greater than 0.5 m (20 in) is documented in the wolverine 
SSA report (Service 2018, p. 87) and in Ray et al. (2017; Table 5-2).
    Interpretation of results and additional analysis relative to 
wolverine den site scale: Recent studies of wolverine populations and 
distribution in Sweden have observed wolverine populations and 
reproductive den sites outside areas modeled with persistent spring 
snow cover (Aronsson and Persson 2016, p. 266; Persson 2017, pers. 
comm.). Another recent study, from Canada, concluded wolverines are 
adaptable and do not require large areas of deep spring snowpack for 
successful reproduction, and may select small areas covered with deep 
snow at a finer scale than can be detected using satellite imagery 
(Webb et al. 2016, p. 1,468). Jokinen et al (2019) reported seven 
wolverine den sites in hollow mounds (caused by the uplifted root 
masses from fallen Black Spruce trees) in the boreal forest of Alberta. 
These areas were largely devoid of spring snow cover (mean distance 
from dens to nearest spring snow cover was 15.2 km) and the authors 
stated wolverines appear to be using ``locally-available denning 
structures in the lowland boreal forest, despite a lack of deep snow, 
persistent spring snow cover, or large boulders documented in other 
studies.'' Regardless as to whether or not wolverines are obligated to 
den in areas of deep snow, the Service was interested in exploring the 
question, ``If snow cover is required for wolverine denning, will there 
be a sufficient amount of significant snow cover in the future in areas 
wolverines have historically used for denning in the contiguous United 
States?'' The Service integrated future Distributed Hydrology Soil 
Vegetation Model projections (2000-2013 averages) of snow-covered area 
(greater than 0.5 m (20 in) depth) on May 1 for Glacier National Park 
and Rocky Mountain National Park with new information obtained from a 
spatial analysis of documented den sites in the contiguous United 
States. This analysis indicated 31 of 34 documented den sites in the 
contiguous United States were located in areas with slopes less than 25 
degrees. Avalanche risk increases significantly in areas with slope 
greater than 25 degrees (Scott 2017, pers. comm.) and thus wolverines 
maybe avoiding these areas for denning due to this risk (Service 2018, 
p. 91).
    The Service calculated areal estimates for future snow covered area 
in both study sites and limited these estimates to elevation bands 
wolverines have used historically for denning and for areas with slopes 
less than 25 degrees. This approach resulted in providing the most 
conservative estimates of future snow covered area in the areas 
wolverines are most likely to use for denning.
    Using the projections prepared by Ray et al. (2017), the wolverine 
SSA report presents the spatial distribution of significant snow-
covered area with slopes less than 25 degrees and within the elevation 
bands expected to be used by wolverines for denning for three future 
climate scenarios in each study area (Service 2018, pp. 92-98). The 
three scenarios for Glacier National Park and Rocky Mountain National 
Park were chosen to span the range of Global Climate Model uncertainty 
regarding temperature and precipitation, and by extension significant 
snow-covered area (Service 2018, p. 93). A detailed description of 
methods describing the process of Global Climate Model selection can be 
found in Ray et al. (2017, pp. 35-38). We found that large portions of 
the study areas meet all three criteria--greater than 0.5 m (20 in) 
snow depth on May 1, at elevation 1,514-2,252 m (4,967-7,389 ft) for 
Glacier National Park or 2,700 to 3,600 m (8,858 to 11,811 ft) for 
Rocky Mountain National Park, and with slopes less than 25 degrees--
across both study sites in the future (See map legends in Figures 10-15 
in the SSA report, (Service 2018, pp. 94-98)).
    We also determined that large tracts (several hundred km\2\/mi\2\) 
of significant snow (greater than 0.5 m (20 in) in depth) are projected 
in close proximity to documented historical den sites across all three 
climate scenarios (Service 2018, pp. 94-95). This analysis is limited 
to Glacier National Park because this is the only area where new snow-
covered area projections and historical den locations were both 
available. Wolverines would not have to travel far, or at all, relative 
to either distance or elevation to reach areas with significant snow-
covered area for denning in the future (Service 2018, pp. 94-95).
    Based on the best available information, we have no reason to 
believe wolverines are confined to previously modeled spring snow 
covered areas. Furthermore, there is no quantitative data documenting 
spring snow patch size or depth to the denning needs of wolverines. 
Even if wolverines must have spring snow for denning, which we do not 
believe to be true, the wolverines in the lower 48 will likely have 
access to areas with significant spring snow cover in the future. Based 
on the new information presented above and in the wolverine SSA report, 
we do not believe wolverines need spring snow cover for denning. 
Nevertheless, new information suggests that spring

[[Page 64644]]

snow cover will not be a limiting resource for wolverines in the 
contiguous United States in the future. Therefore, based on the best 
available information, we do not consider the effects of changes in 
snowpack from the combination of increased temperature and changes in 
precipitation patterns to be a threat to the wolverine.
Wildland Fire
    The wolverine SSA report includes a discussion of available 
information on the relationship of predicted future climate conditions 
on wildland fire projections in the western United States (Service 
2018, pp. 99-100). In summary, based on these projections, wildland 
fire risk is likely to increase in the western United States, with 
future patterns and trends of wildland fire dependent on several 
factors (e.g., degree of warming and drought conditions, fuel and soil 
moisture, wildland fire management practices, elevation) and geographic 
region (Service 2018, p. 100). However, given the diversity of habitats 
occupied by wolverines, their occupancy of high elevations, extensive 
mobility, and the positive effect wildland fire may have on wolverine 
prey species, wildland fire represents a limited stressor, in scope and 
scale, to wolverine habitat and its prey in the contiguous United 
States range (Service 2018, pp. 63-64).
    To summarize, based on the best available information, the 
cumulative effects of wildland fire and climate change (e.g., snowpack) 
will continue to represent a low impact to the wolverine and its 
habitat into the mid-21st century, based on climate change projections 
(Service 2018, p. 100).
Other Cumulative Effects
    Finally, we note here that the effects of climate change on 
snowpack are projected to negatively affect the season lengths for 
winter recreational activities, such as skiing and snowmobiling, 
shortening the winter recreation season (Service 2018, pp. 100-101). A 
shorter winter recreation season would likely decrease the amount of 
winter recreation related disturbance occurring in wolverine habitat 
and fewer effects to wolverines. Alternatively, even though winter 
recreation seasons will be shorter, we could see more winter human 
activity at higher elevations due to snow loss at lower elevations. 
However, even at current levels, we do not consider winter recreational 
activities to be a threat to wolverine in the contiguous United States. 
For further discussion of winter recreational activities see the 
wolverine SSA report (Service 2018, pp. 100-101).
Summary of Future Conditions
    Climate change model projections for the range of the wolverine 
within the contiguous United States indicate increases in temperature 
by the mid-21st century as compared to early to mid-20th century values 
(Service 2018, p. 101). The degree of future warming varies by region; 
area specific discussions are included in the SSA report (Service 2018, 
pp. 73-80). Precipitation patterns into the future are less clear as 
the climate models show significant disagreement in their many regional 
projections. Although drought conditions in the western United States 
are not unusual, drought duration and intensity have the potential to 
be exacerbated by projected temperature increases. Projected 
temperature and precipitation changes will affect future snow cover and 
the persistence of snow on the landscape.
    Snow cover is projected to decline in response to warming 
temperatures and changing precipitation patterns, but this varies by 
elevation, topography, and by geographic region (Service 2018, p. 101). 
Simulations of natural snow accumulation at winter recreation locations 
have found that, overall, higher elevation areas (e.g., Rocky 
Mountains, Sierra Nevada Mountains) are more resilient to projected 
changes in temperature and precipitation as compared to lower 
elevations (Wobus et al. 2017, p. 12). In general, models indicate 
higher elevations will retain more snow cover than lower elevations, 
particularly in early spring (April 30/May 1) (Service 2018, p. 101). 
In the wolverine SSA report, we present results from several recent 
climate models projecting snowpack declines in the western United 
States (Service 2018, pp. 83-100). More specifically, we reviewed a new 
analysis (Ray et al. 2017, entire) that modeled future snow persistence 
for Glacier and Rocky Mountain National Parks (areas that encompass the 
latitudinal and elevational range of the wolverine in the contiguous 
United States) at high spatial resolution and at the den-site scale 
(Service 2018, pp. 85-98). The results indicate large areas (several 
hundred km\2\/mi\2\ for each site) of future snow (greater than 0.5 m 
(20 in) in depth) will persist on May 1 (end of the denning season) at 
elevations currently used by wolverines for denning (Service 2018, pp. 
93-98). This is true, on average, across the range of climate models 
used out to approximately year 2055.
    Within their North American range, wolverines are found in a 
variety of habitats within primarily high-elevation areas of the 
western-northwestern United States, and exhibit wide-ranging movements 
(Service 2018, p. 102). Wolverines select den sites for differing 
characteristics depending on location, and natal den locations are 
generally associated with snow cover; however, many natal dens have 
been observed outside of the circumpolar boundary of the snow model 
presented in Copeland et al. (2010) (Service 2018, p. 103), 
particularly in Scandinavia. In addition, reproductive success of 
wolverines has not been evaluated relative to the depth and persistence 
of snow cover at the den site scale, or in combination with these or 
other important key life-history characteristics, including avoidance 
and/or protection from predators, prey availability, availability of 
food-caching habitat.
    We also considered temperature and precipitation projections from 
climate change models in conjunction with wildland fire risk. This risk 
is likely to increase across the western United States, but patterns 
and trends are dependent on several factors (e.g., degree of warming 
and drought conditions, fuel and soil moisture) and geographic region 
(Service 2018, p. 102) and wildland fire represents a limited stressor, 
in scope and scale, to wolverine habitat and prey as described above in 
Effects from Wildland Fire.
Overall Assessment
    The wolverine's current potential extent of occurrence includes the 
western-northwestern United States (see Figure 2), large areas of 
Canada, and Alaska (Service 2018, p. 16). The wolverine is found in a 
variety of habitats in North America, but generally occurs in high-
elevation, relatively inaccessible locations (Service 2018, p. 102). In 
the contiguous United States, potentially suitable habitat (i.e., 
primary habitat), as determined by the physical and ecological features 
and the ecological needs of the wolverine, is estimated at 164,125 
km\2\ (63,369 mi\2\) (Inman et al. 2013, p. 281). Based on our review 
of available relevant literature, we identified the physical and 
ecological needs of the species as follows: large territories in 
relatively inaccessible landscapes, at high elevation (1,800 to 3,500 m 
(5,906 to 11,483 ft)) within the contiguous United States; access to a 
variety of food resources, that varies with seasons; and reproductive 
behavior linked to both temporal and physical features (Service 2018, 
p. 104). These needs are currently met for wolverines in the contiguous 
United States and are expected to be met in the future (i.e., in 38-50 
years) (Service 2018, p. 104).

[[Page 64645]]

    We recognize there is limited information available for the 
wolverine, including population estimates and abundance trends. In the 
contiguous United States, the structure of the wolverine population is 
represented as a metapopulation, although its genetic structure 
relative to its entire North American range has not been 
comprehensively evaluated (Service 2018, p. 102). Wolverine populations 
in Alaska are considered to be continuous with populations in the Yukon 
and British Columbia provinces of Canada based on genetic studies 
(COSEWIC 2014, p. 37). Similarly, studies of wolverines in the North 
Cascades region have documented recent movement of wolverines from 
Washington into British Columbia (Aubry et al. 2016, pp. 16, 20) and 
from Idaho (Lucid et al. 2016, p. 184) to British Columbia, and earlier 
from Montana to British Columbia and Alberta (e.g., Newby and Wright 
1955, p. 252).
    We present in our SSA report a detailed discussion of wolverine 
reproductive behavior. Based on the best available information, 
wolverines select den sites for different characteristics depending on 
location. Dens located under snow cover may be related to wolverine 
distribution based on other life-history traits, including 
morphological, demographic, and behavioral adaptations that allow them 
to successfully compete for food resources (Inman 2013, pers. comm.). 
Structure (e.g., uprooted trees, boulders and talus fields) appears to 
be an important requirement for natal den sites. However, reproductive 
success of wolverines has not been evaluated relative to the depth and 
persistence of snow cover, or in combination with these or other 
important characteristics, including prey availability and predator 
avoidance. Recent studies of wolverine populations and distribution in 
Sweden have observed wolverine populations and reproductive den sites 
outside areas modeled with persistent spring snow cover (Aronsson and 
Persson 2016; Persson 2017, pers. comm.). Another recent study 
concluded that wolverines are adaptable and do not require large areas 
of deep spring snowpack for successful reproduction, and may select 
small areas covered with deep snow at a finer scale than can be 
detected using satellite imagery (Webb et al. 2016, p. 1,468). Most 
recently, wolverine dens have been documented in boreal Alberta, 
Canada, several kilometers away from spring snow cover, in hollow 
mounds caused by fallen spruce trees (Jokinen et al, 2019). We would 
not expect fallen trees, and the potentially suitable denning sites 
created by them, to be a limiting resource in wolverine habitat.
    We identified several potential stressors that may be affecting the 
species and its habitat currently or in the future, including impacts 
associated with climate change effects. Based on the best available 
information, demographic risks to the species from either known or most 
likely potential stressors (i.e., disturbance due to winter 
recreational activities, other human disturbances, effects of wildland 
fire, disease, predation, overutilization, genetic diversity, small-
population effects, climate change, and cumulative effects) are low 
based on our evaluation of the best available information as it applies 
to current and potential future conditions for the wolverine and in the 
context of the attributes that affect the needs of the species (Service 
2018, p. 103).
    Climate change model projections for the range of the wolverine 
within the contiguous United States indicate increases in temperature 
by the mid-21st century as compared to early to mid-20th century values 
(Service 2018, p. 103). Our evaluation of climate change indicates that 
snow cover is projected to decline in response to warming temperatures 
and changing precipitation patterns, but this varies by elevation, 
topography, and by geographic region (Service 2018, p. 103). In 
general, models indicate higher elevations will retain more snow cover 
than lower elevations, particularly in early spring (April 30/May 1) 
(Service 2018, p. 103). Although the persistence of spring snow has not 
yet been determined to be critical to wolverine survival in North 
America, our review of projected snow persistence (to approximately 
2055) within the Northern and Southern Rocky Mountains, indicates 
several hundred km\2\/mi\2\ of deep snow will persist on May 1 at 
elevations used by the wolverine for denning (Service 2018, p. 103).
    Legal protections of the wolverine in the contiguous United States 
include State listing in California and Oregon (as threatened); 
Colorado (as endangered); candidate species status in Washington; 
protected as a non-game species in Idaho and Wyoming; a species of 
concern and furbearer with a closed season in Montana; and protected 
from collection, importation, and possession in Utah (Service 2018, p. 
107). Trapping or hunting of wolverines is currently prohibited in the 
contiguous United States. Trapping effort along the U.S.-Canada border 
does not represent a barrier to wolverine movement and dispersal along 
the international border (Service 2018, p. 103).
    Management actions for conservation of the wolverine and its 
habitat are included within State Wildlife Action Plans, the Management 
Plan for the Conservation of Wolverines in Idaho (IDFG 2014), and USDA 
Forest Service Land and Resource Management Plans (Service 2018, 
Appendix G). Various provisions of these plans include, but are not 
limited to, winter road closures, fire management, and land acquisition 
or conservation easements. These management measures, currently and in 
the future, will alleviate effects associated with potential impacts 
related to stressors. However, we do not rely on the management 
measures and conservation efforts contained in these plans to support 
our listing decision. In addition, the WAFWA Wildlife Chiefs Wolverine 
Subcommittee is providing a forum for western States to work 
collaboratively with each other and with the Service and other partners 
for conserving wolverines found in the western-northwestern United 
States, and, to date, approximately $1.5 million of funding has been 
applied towards conservation and management actions for the wolverine 
(e.g., Western States Wolverine Conservation Project) (McDonald 2017, 
pers. comm.).

Determination of Species Status

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of ``endangered species'' or 
``threatened species.'' The Act defines an ``endangered species'' as a 
species that is ``in danger of extinction throughout all or a 
significant portion of its range,'' and a ``threatened species'' as a 
species that is ``likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range.'' The Act requires that we determine whether a species meets the 
definition of ``endangered species'' or ``threatened species'' because 
of any of the following 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.

[[Page 64646]]

Determination of Status Throughout All of Its Range in the Contiguous 
United States

    Since the publication of the February 4, 2013, proposed rule (78 FR 
7864) and reinstatement of that proposed rule on October 18, 2016 (81 
FR 71670), we prepared a comprehensive assessment of the current and 
future status of wolverines in the contiguous United States as 
presented in the wolverine SSA report (Service 2018, entire). New 
information from recent surveys and a reevaluation of the species' 
current range, new genetic information, new studies of wolverine 
reproductive behavior and denning habitat, and results from detailed 
modeling of future spring snow persistence are included in the 
wolverine SSA report and contribute to our current understanding of the 
species. The wolverine SSA report also provides a comprehensive summary 
of wolverine life history and ecology, including an assessment of 
wolverine physiology, and an analysis of new information on wolverine 
trapping pressure in Canada near the United States-Canada border, as 
well as analyses of new information relevant to other potential threats 
to the species. We have carefully assessed the best scientific and 
commercial information available regarding the past, present, and 
future threats to North American wolverines in the contiguous United 
States including effects from roads (Factors A and E); disturbance due 
to winter recreational activity (Factors A and E); other human 
disturbance (Factors A and E); effects from wildland fire (Factor A); 
disease (Factor C); predation (Factor C); overutilization (trapping) 
(Factor B); genetic diversity (Factor E); small-population effects 
(Factor E); and climate change (Factors A and E). We also assessed the 
adequacy of existing regulatory mechanisms (Factor D).
    Consideration of Cumulative Effects--Threats can work in concert 
with one another to cumulatively create conditions that may impact the 
wolverine or its habitat beyond the scope of each individual threat. 
See the Climate Change and Potential for Cumulative Effects section 
above and the wolverine SSA report for an in-depth analysis of 
cumulative effects (Service 2018, pp. 82-101). We note that by using 
the SSA framework to guide our analysis of the scientific information 
documented in the SSA report, we have not only analyzed individual 
effects on the species, but we have also analyzed their potential 
cumulative effects. We incorporate the cumulative effects into our SSA 
analysis when we characterize the current and future condition of the 
species. Our assessment of the current and future conditions 
encompasses and incorporates the threats individually and cumulatively. 
Because the SSA framework considers not just the presence of the 
factors, but to what degree they collectively influence risk to the 
entire species, our assessment integrates the cumulative effects of the 
factors.
    Our future-condition analysis in the wolverine SSA report includes 
the potential conditions that the species or its habitat may face, that 
is, the most probable scenario if those conditions are realized in the 
future. This most probable scenario includes consideration of the 
sources that have the potential to most likely impact the species at 
the population or rangewide scales in the future, including potential 
cumulative impacts. Given an expected increase in temperature in the 
western United States, the best available information indicates that, 
if there are any cumulative impacts in the future, the most likely to 
have population-level effects on wolverine in the contiguous United 
States could be: (1) Changes in snowpack from the combination of 
increased temperature and changes in precipitation patterns, or (2) 
changes in snowpack and increase in wildland fire potential (Service 
2018, p. 83). The best available information does not indicate that the 
effects of trapping and mortality from roads will act cumulatively with 
effects of climate change, and those stressors are expected to remain 
low-level impacts into the future. We provide a detailed analysis of 
climate change and the potential for cumulative effects in the 
wolverine SSA report (Service 2018, pp. 82-102). Based on the best 
available information, the cumulative effects of wildland fire and 
climate change (e.g., snowpack) will continue to represent a low impact 
to the wolverine and its habitat into the mid-21st century, based on 
climate change projections.
    Resilience, Representation, and Redundancy--In order to 
characterize a species' viability and demographic risks, we consider 
the concepts of resilience, representation, and redundancy. We also 
consider known and potential stressors that may negatively impact the 
physical and biological features that the species needs for survival 
and reproduction. Stressors are expressed as risks to its demographic 
features such as abundance, population and spatial structure, and 
genetic or ecological diversity. We consider the level of impact a 
stressor may have on a species along with the consideration of 
demographic factors (e.g., whether a species has stable, increasing, or 
decreasing trends in abundance, population growth rates, diversity of 
populations, and loss or degradation of habitat).
    Wolverine populations in much of North America are still recovering 
from large losses of individuals from unregulated hunting and 
persecution pressures in the late 1880s into the mid-20th century 
(Service 2018, p. 104). Surveys conducted in the winter of 2015-2016 
and 2016-2017 continue to document its presence within portions of its 
historical range in the western contiguous United States 
(representation) (Service 2018, p. 104).
    Redundancy, the ability to rebound after stochastic perturbation, 
can be characterized by the distribution and connectivity of 
populations. In considering wolverine in the contiguous United States, 
individuals are found in alpine, boreal, and subalpine habitats, with 
breeding populations in four western States. Additionally, wolverines 
in the contiguous United States are connected to wolverine populations 
in Canada along the U.S.-Canada border, which contributes to current 
and future redundancy (Service 2018, p. 104).
    Resiliency, the ability to withstand stochastic events, can be 
characterized by numbers of individuals and abundance trends. As 
indicated above, actual current population size, growth rate, and 
current population trends are unknown for wolverines in the contiguous 
United States due to the lack of abundance information. However, 
according to recent estimates, Canada's western subpopulation (which is 
connected to wolverines in the contiguous United States) has been 
estimated at 15,688 to 23,830 adult wolverines, with expansion of 
wolverines into historically occupied areas in both Canada and the 
contiguous United States with movement across both international 
borders (Service 2018, pp. 54, 105). The 2014 Committee on the Status 
of Endangered Wildlife in Canada report concluded that a climate-driven 
decline in wolverine populations in North America is not evident at 
this time in much of its range (COSEWIC 2014, p. 22). Wolverine 
populations in Canada are considered stable (Service 2018, p. 105). We 
also note that density estimates indicate no declining trend in 
wolverine populations in Alaska (Service 2018, p. 105). We recognize 
that there is limited information on populations (representation) or 
genetic diversity (resiliency and representation) for the wolverine in 
the contiguous United States, and no comprehensive studies to indicate 
what a viable (or

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minimal) wolverine population size should be across its North American 
range. However, the best available information does not indicate either 
increasing or declining numbers of the wolverine in North America, 
including the contiguous United States. Further, at this time, the best 
available information does not indicate that the species' abundance is 
significantly impacted by the stressors evaluated (singly or 
cumulatively), and this situation is unlikely to change in the future, 
supporting current and future resiliency.
    As discussed in the wolverine SSA report, both direct and 
cumulative effects of climate change (e.g., higher temperatures, loss 
of snow cover, wildland fire) may affect the resilience of the 
wolverine in the future by creating an environment that is less 
favorable to its physiological and ecological needs (Service 2018, p. 
105). We are unaware of studies of the wolverine that have formally 
evaluated the species' responses (e.g., reproductive success or 
survival) to warming temperatures or other climate change effects.
    As described in the wolverine SSA report, the best available 
information indicates confirmed observations of wolverines denning in 
areas with patchy snow cover in Alaska, Canada, and Scandinavia 
(Service 2018, p. 105). Further, using fine-scale snow modeling, we 
estimated that large areas of spring snow (May 1) will remain within 
Glacier National Park, where wolverines are known to den (Service 2018, 
p. 105). Given their high rate of movement, large dispersal distances, 
including travel through areas not covered with snow, and other life-
history traits (e.g., behavioral plasticity) observed in wolverines, we 
do not predict a significant loss of individual and population 
resiliency to the species in the future (i.e., 38-50 years) within its 
North America range, including the contiguous United States (Service 
2018, p. 105).
    Currently, we are unaware of any documented specific risks for the 
wolverine related to a substantial change or loss of diversity in life-
history traits, population demographics, morphology, behavior, or 
genetic characteristics that can be used to characterize species 
representation (the ability to adapt to change). Rates of dispersal or 
gene flow are not known to have changed, and recent evidence supports 
continued connectivity with contiguous United States wolverines and 
wolverines in Canada. Additionally, there is no currently available 
information to indicate that the current abundance of the wolverine 
across its current potential extent in the contiguous United States is 
at a level that is causing inbreeding depression or that loss of 
genetic variation is affecting representation or that would affect 
representation in the future (Service 2018, p. 105). Nor is there any 
information to indicate that this species is unable to adapt or adjust 
to changing conditions (e.g., potential reduction in snow cover). We do 
not expect a reduction in representation of the wolverines in the 
contiguous United States in the future. We have determined that the 
needs of the species are provided within the contiguous United States 
currently and into the future. Thus, after assessing the best available 
information, we conclude that the North American wolverine in the 
contiguous United States is not in danger of extinction throughout all 
of its range (endangered) nor is it likely to become so in the 
foreseeable future (threatened).
    Because we determined that the North American wolverine in the 
contiguous United States is not in danger of extinction or likely to 
become so in the foreseeable future throughout all of its range, we 
will consider whether there are any significant portions of its range 
in which it is in danger of extinction or likely to become so in the 
foreseeable future.

Determination of Status Throughout a Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
in the foreseeable future throughout all or a significant portion of 
its range. Having determined that the wolverine is not in danger of 
extinction or likely to become so in the foreseeable future throughout 
all of its range, we now consider whether it may be in danger of 
extinction or likely to become so in the foreseeable future in a 
significant portion of its range--that is, whether there is any portion 
of the species' range for which it is true that both (1) the portion is 
significant; and, (2) the species is in danger of extinction now or 
likely to become so in the foreseeable future in that portion. 
Depending on the case, it might be more efficient for us to address the 
``significance'' question or the ``status'' question first. We can 
choose to address either question first. Regardless of which question 
we address first, if we reach a negative answer with respect to the 
first question that we address, we do not need to evaluate the other 
question for that portion of the species' range.
    In undertaking this analysis for the North American wolverine in 
the contiguous United States, we choose to address the status question 
first--we consider information pertaining to the geographic 
distribution of both the species and the threats that the species faces 
to identify any portions of the range where the species is endangered 
or threatened.
    For the North American wolverine in the contiguous United States, 
we considered whether the threats are geographically concentrated in 
any portion of the species' range at a biologically meaningful scale. 
We examined the following threats: effects from roads, disturbance due 
to winter recreational activity, other human disturbance, wildland 
fire, disease, predation, overutilization (trapping), genetic 
diversity, small-population effects, climate change, and cumulative 
impacts of these potential threats (Service 2018, entire). All of these 
potential stressors are relatively evenly distributed geographically 
throughout the range of the wolverine in the contiguous United States. 
We found no concentration of threats in any portion of the wolverine's 
range at a biologically meaningful scale. Therefore, no portion of the 
species' range can provide a basis for determining that the species is 
in danger of extinction now or likely to become so in the foreseeable 
future in a significant portion of its range, and we find the species 
is not in danger of extinction now or likely to become so in the 
foreseeable future in any significant portion of its range. This is 
consistent with the courts' holdings in Desert Survivors v. Department 
of the Interior, No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 
24, 2018), and Center for Biological Diversity v. Jewell, 248 F. Supp. 
3d, 946, 959 (D. Ariz. 2017).

Determination of Status

    We have reviewed the best available scientific and commercial 
information regarding the past, present, and future threats to the 
North American wolverine in the contiguous United States and we have 
determined that, if it were to be a listable entity, it does not meet 
the definition of an endangered species or a threatened species in 
accordance with sections 3(6) and 3(20) of the Act. Furthermore, we 
have determined that the population of wolverines in the contiguous 
United States is not a DPS. As a consequence of these determinations, 
we are withdrawing our proposed rule to list the distinct population 
segment of the North American wolverine occurring in the contiguous 
United States as a threatened species.

[[Page 64648]]

References Cited

    A complete list of references cited in this document and the 
wolverine SSA report are available on the internet at http://www.regulations.gov at Docket No. FWS-R6-ES-2016-0106 and upon request 
from the Montana Ecological Services Office (see FOR FURTHER 
INFORMATION CONTACT).

Authors

    The primary authors of this document are the staff members of the 
Montana Ecological Services Office and the Mountain-Prairie Regional 
Office.

Signing Authority

    The Director, U.S. Fish and Wildlife Service, approved this 
document and authorized the undersigned to sign and submit the document 
to the Office of the Federal Register for publication electronically as 
an official document of the U.S. Fish and Wildlife Service. Aurelia 
Skipwith, Director, U.S. Fish and Wildlife Service, approved this 
document on August 10, 2020, for publication.

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

Madonna Baucum,
Regulations and Policy Chief, Division of Policy, Economics, Risk 
Management, and Analytics of the Joint Administrative Operations, U.S. 
Fish and Wildlife Service.
[FR Doc. 2020-19538 Filed 10-9-20; 8:45 am]
BILLING CODE 4333-15-P