Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for North American Wolverine, 83726-83772 [2023-26206]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 88, Number 229 (Thursday, November 30, 2023)]
[Rules and Regulations]
[Pages 83726-83772]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-26206]



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Vol. 88

Thursday,

No. 229

November 30, 2023

Part IV





 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; Threatened Species 
Status With Section 4(d) Rule for North American Wolverine; Final and 
Interim Rule

Federal Register / Vol. 88 , No. 229 / Thursday, November 30, 2023 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R6-ES-2023-0216; FF09E21000 FXES11110900000 245]
RIN 1018-BH27


Endangered and Threatened Wildlife and Plants; Threatened Species 
Status With Section 4(d) Rule for North American Wolverine

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule and interim rule with request for comments.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
threatened species status under the Endangered Species Act of 1973 
(Act), as amended, for the distinct population segment (DPS) of the 
North American wolverine (Gulo gulo luscus) occurring in the contiguous 
United States. This rule adds the contiguous U.S. DPS of the North 
American wolverine to the Federal List of Endangered and Threatened 
Wildlife. We are also issuing an interim rule under the authority of 
section 4(d) of the Act (an ``interim 4(d) rule'') that provides the 
prohibitions, and exceptions to those prohibitions, necessary and 
advisable for the conservation of the contiguous U.S. DPS of the North 
American wolverine.

DATES: 
    Effective date: This rule is effective January 2, 2024.
    Comments due: Comments on the interim 4(d) rule must be received or 
postmarked by January 29, 2024.

ADDRESSES: 
    Written comments on the interim 4(d) rule: You may submit comments 
on the interim 4(d) rule by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Search box, enter FWS-R6-ES-2023-0216, 
which is the docket number for this rulemaking. Then click on the 
Search button. On the resulting page, in the panel on the left side of 
the screen, under the Document Type heading, click on the Rules box to 
locate this document. You may submit a comment by clicking on 
``Comment.''
    (2) By hard copy: U.S. mail: Public Comments Processing, Attn: FWS-
R6-ES-2023-0216; U.S. Fish and Wildlife Service; MS: PRB/3W; 5275 
Leesburg Pike; Falls Church, VA 22041-3803.
    We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see Public Comments Solicited on the Interim 4(d) Rule, below, for 
more information).
    Availability of supporting materials: This document is available on 
the internet at https://www.regulations.gov and at https://ecos.fws.gov/ecp/species/5123. Supporting materials we used in 
preparing this rule, including the 2018 species status assessment (SSA) 
report and the 2023 addendum to the SSA report, are available on the 
Service's website at https://ecos.fws.gov/ecp/species/5123, at https://www.regulations.gov at Docket No. FWS-R6-ES-2023-0216, or both.

FOR FURTHER INFORMATION CONTACT: Jodi Bush, U.S. Fish and Wildlife 
Service, Pacific Region, 911 NE 11th Ave., Portland, OR 97232; 
telephone: (503) 231-6131. Individuals in the United States who are 
deaf, deafblind, hard of hearing, or have a speech disability may dial 
711 (TTY, TDD, or TeleBraille) to access telecommunications relay 
services. Individuals outside the United States should use the relay 
services offered within their country to make international calls to 
the point-of-contact in the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

Final Rule To List the Contiguous U.S. DPS of the North American 
Wolverine

    Why we need to publish a rule. The Act (16 U.S.C. 1531 et seq.) 
defines ``species'' as any subspecies of fish or wildlife or plants, 
and any distinct population segment (DPS) of any species of vertebrate 
fish or wildlife which interbreeds when mature. Under the Act, a 
species warrants listing if it meets the definition of an endangered 
species (in danger of extinction throughout all or a significant 
portion of its range) or a threatened species (likely to become an 
endangered species within the foreseeable future throughout all or a 
significant portion of its range). If we determine that a species 
warrants listing, we must list the species promptly and designate the 
species' critical habitat to the maximum extent prudent and 
determinable. We have determined that the DPS of the North American 
wolverine occurring in the contiguous United States (the ``contiguous 
U.S. DPS'') meets the Act's definition of a threatened species; 
therefore, we are listing it as such. Listing a species as an 
endangered or threatened species can be completed only by issuing a 
rule through the Administrative Procedure Act rulemaking process (5 
U.S.C. 551 et seq.).
    What this document does. This document is both (1) a final rule 
listing the contiguous U.S. DPS of the North American wolverine as a 
threatened species under the Act; and (2) an interim rule issued under 
the authority of section 4(d) of the Act (an ``interim 4(d) rule'') 
providing the prohibitions, and exceptions to those prohibitions, that 
are necessary and advisable to provide for the conservation of the 
contiguous U.S. DPS of the North American wolverine.
    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 contiguous U.S. DPS of 
the North American wolverine is a threatened species due primarily to 
the ongoing and increasing impacts of climate change and associated 
habitat degradation and fragmentation.
    Section 4(a)(3) of the Act requires the Secretary of the Interior 
(Secretary) to designate critical habitat concurrent with listing to 
the maximum extent prudent and determinable. We have not yet obtained 
the necessary economic information needed to develop a proposed 
critical habitat designation for the contiguous U.S. DPS of the North 
American wolverine. Therefore, we find that designation of critical 
habitat for the DPS is currently not determinable.

Interim 4(d) Rule

    The need for the regulatory action and how the action will meet 
that need. Consistent with section 4(d) of the Act, this interim 4(d) 
rule provides measures that are tailored to our current understanding 
of the conservation needs of the North American wolverine.
    Under section 4(d) of the Act, the Secretary of the Interior has 
discretion to issue such regulations as she deems necessary and 
advisable to provide for the conservation of the species. The Secretary 
also has the discretion to prohibit by regulation with respect to a 
threatened species, any act prohibited by section 9(a)(1) of the Act.
    Summary of the major provisions of the regulatory action. This 
interim 4(d) rule will provide for the conservation of the contiguous 
U.S. DPS of the North American wolverine by prohibiting the following 
activities, unless they fall

[[Page 83727]]

within the specific identified exceptions or are otherwise authorized 
or permitted: importing or exporting; take; possession and other acts 
with unlawfully taken specimens; delivering, receiving, carrying, 
transporting, or shipping in interstate or foreign commerce in the 
course of commercial activity; or selling or offering for sale in 
interstate or foreign commerce.
    The interim 4(d) rule will also provide for the conservation of the 
species by allowing exceptions to the general prohibitions against 
``take'' of the species in support of conservation actions and 
otherwise lawful activities that could take wolverines but at minimal 
levels not likely to have a negative impact on the species' 
conservation. The exceptions include take due to scientific research 
conducted on wolverines by a Federal or Tribal biologist in the course 
of their official duties, incidental take resulting from forest 
management activities for the purposes of reducing the risk or severity 
of wildfire, and incidental take resulting from legal trapping 
conducted consistent with State and Tribal trapping rules or guidelines 
that contain steps to minimize the potential for capture of wolverine.

Supporting Documents

    A team prepared a species status assessment (SSA) for the North 
American wolverine (Gulo gulo luscus) (Service 2018, entire) (hereafter 
referred to as the wolverine SSA report). The SSA team was composed of 
U.S. Fish and Wildlife Service (Service) biologists, who consulted with 
other species experts. The wolverine SSA report represented a 
compilation of the best scientific and commercial data available (known 
at that time) concerning the status of the North American wolverine, 
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.
    More recently, the Service prepared an SSA addendum for the North 
American wolverine (Gulo gulo luscus) (Service 2023, entire) (hereafter 
referred to as the wolverine SSA report addendum). The wolverine SSA 
report addendum contains a synthesis of relevant new information that 
has become available since the 2018 wolverine SSA report. The wolverine 
SSA report addendum 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 addendum also underwent technical review by State, 
Federal, and Tribal biologists.
    The wolverine SSA report, the wolverine SSA report addendum, and 
other materials relating to this rulemaking can be found at the 
Service's website at https://ecos.fws.gov/ecp/species/5123, and at 
https://www.regulations.gov at Docket No. FWS-R6-ES-2023-0216.

Previous Federal Actions

    On February 4, 2013, we published in the Federal Register (78 FR 
7864) a proposed rule to list the DPS of the North American wolverine 
occurring in the contiguous United States as a threatened species under 
the Act, with a proposed rule under section 4(d) of the Act that 
outlined the prohibitions, and exceptions to those prohibitions, 
necessary and advisable for the conservation of the wolverine. Please 
refer to that February 4, 2013, proposed rule (78 FR 7864) for a 
detailed description of previous Federal actions concerning the 
wolverine prior to 2013. We published a separate proposed rule in the 
Federal Register on February 4, 2013 (78 FR 7890), 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. 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 available climate change 
information used to determine the extent of threats to the contiguous 
U.S. DPS of the North American wolverine. Based on this substantial 
disagreement regarding the sufficiency or accuracy of the available 
data relevant to the proposed listing, on February 5, 2014, we 
announced in the Federal Register (79 FR 6874) a 6-month extension of 
the final determination of whether to list the contiguous U.S. DPS of 
North American wolverine as a threatened species under the Act. That 
document reopened the comment period on the February 4, 2013, proposed 
listing rule for an additional 90 days.
    On August 13, 2014, we published in the Federal Register (79 FR 
47522) a document withdrawing both proposed rules published on February 
4, 2013: (1) the proposed rule to list the contiguous U.S. DPS of the 
North American wolverine as a threatened species under the Act, 
including the provisions proposed under section 4(d) of the Act; and 
(2) the proposed NEP designation under section 10(j) of the Act for the 
North American wolverine in the Southern Rocky Mountains of Colorado, 
northern New Mexico, and southern Wyoming. These withdrawals were based 
on our conclusion that the factors affecting the DPS as identified in 
the listing proposed rule were not as significant as believed at the 
time of that proposed rule's publication in 2013.
    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 February 4, 2013, proposed rule to 
list the contiguous U.S. DPS of the North American wolverine. Numerous 
parties intervened in the litigation. These three cases were 
consolidated, and on April 4, 2016, the court issued a decision. The 
court granted plaintiffs' 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 the range policy to the wolverine. As a result 
of the court order, the August 13, 2014, withdrawal (79 FR 47522) of 
the February 4, 2013, proposed listing rule was vacated and remanded to 
the Service for further consideration consistent with the order.
    In effect, the court's action returned the process to the proposed 
rule stage, and the status of the contiguous U.S. DPS of the North 
American 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 in the Federal Register (81 FR 71670) a document 
reopening the comment period on the February 4, 2013, proposed rule to 
list the DPS of the North American wolverine occurring in the 
contiguous United States as threatened under the Act (78 FR 7864). The 
October 18, 2016, publication also requested new information and 
announced that we were initiating 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

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whether the species is not warranted for listing. Both new and updated 
information and analyses presented in the wolverine 2018 SSA report, 
along with public comments, prompted us to reevaluate our previous 
assessment of the DPS (presented in our 2013 proposed listing rule (78 
FR 7864), which in turn relied on the DPS analysis completed in our 
2010 12-month finding (75 FR 78030)) with respect to the North American 
wolverine in the contiguous United States.
    On October 13, 2020, we published in the Federal Register (85 FR 
64618) another document withdrawing the February 4, 2013, proposed rule 
to list the DPS of the North American wolverine occurring in the 
contiguous United States as threatened under the Act. Our 2020 
withdrawal decision was based on our conclusion that the factors 
affecting the North American wolverine occurring in the contiguous 
United States as identified in the 2013 proposed listing rule were not 
as significant as believed at the time of the proposed rule's 
publication in 2013. We also found that the North American wolverines 
occurring in the contiguous United States did not qualify as a DPS.
    The Center for Biological Diversity and WildEarth Guardians filed 
lawsuits in the District Court for the District of Montana challenging 
the Service's 2020 decision to withdraw the February 4, 2013, proposal 
to list the contiguous U.S. DPS of the North American wolverine. The 
cases were consolidated, and the State of Idaho's motion to intervene 
was granted. On February 4, 2022, the Service filed a motion asking the 
court to voluntarily return (remand) the 2020 withdrawal decision to 
the Service to allow the Service to re-examine the decision in light of 
the intervening decision in Center for Biological Diversity v. Haaland, 
998 F.3d 1061 (9th Cir. 2021) (``Pacific Walrus Decision'') and to 
reevaluate the decision in light of new scientific information that had 
become available since the completion of the 2018 SSA. The Service also 
requested that the 2020 withdrawal decision remain in effect pending 
that reevaluation. On May 26, 2022, the court granted the Service's 
request for a voluntary remand of the 2020 withdrawal decision, but the 
court decided to vacate the withdrawal decision (Ctr. for Biological 
Diversity v. Haaland, No. CV 20-181-M-DWM (D. Mont. May 26, 2022)).
    The court's May 26, 2022, action returned the listing process for 
the North American wolverine to the proposed rule stage. On November 
23, 2022, the Service published in the Federal Register (87 FR 71557) a 
document soliciting new information on the North American wolverine and 
notifying the public that the February 4, 2013, proposed rule to list 
the contiguous U.S. DPS of the North American wolverine as threatened 
under the Act (78 FR 7864) had been reinstated. As of May 26, 2022, for 
purposes of consultation under section 7 of the Act, the North American 
wolverine was again a species proposed for listing and subject to 
conferencing requirements.
    The Service then completed the wolverine SSA report addendum 
(Service 2023, entire), which contains a synthesis of all relevant new 
information that has become available since the 2018 wolverine SSA 
report to inform this final listing rule and the associated interim 
4(d) rule.

Peer Review

    Our assessment of the status of the North American wolverine 
contained in this document is supported by information in both the 2018 
SSA report (Service 2018, entire) and the 2023 wolverine SSA report 
addendum (Service 2023, entire). In accordance with our joint policy on 
peer review published in the Federal Register on July 1, 1994 (59 FR 
34270), and our August 22, 2016, memorandum updating and clarifying the 
role of peer review in listing actions under the Act, we solicited 
independent scientific review of the information contained in the 2018 
wolverine SSA report. We sent the SSA report to four independent peer 
reviewers and received four responses; we incorporated the results of 
that review into the SSA report, as appropriate. More recently, we 
solicited independent scientific review of the 2023 wolverine SSA 
report addendum. We sent the wolverine SSA report addendum to six peer 
reviewers and received three responses; we incorporated the results of 
the peer review into the wolverine SSA report addendum, as appropriate. 
The peer reviews on the wolverine SSA report and the wolverine SSA 
report addendum can be found at https://www.regulations.gov.

Summary of Changes

    Since the publication of the February 4, 2013, proposed listing 
rule (78 FR 7864), the development of the 2018 SSA report (Service 
2018, entire), and the publication of the October 13, 2020, withdrawal 
document (85 FR 64618), a substantial number of new studies have become 
available, refining our understanding of wolverine biology and threats 
affecting North American wolverines in the contiguous United States. We 
incorporated this new information into the 2023 wolverine SSA report 
addendum. We summarize the information most salient to our 
determination in this final rule below. We also discuss these changes 
where appropriate in the remainder of the document to provide further 
detail and context.

Ecological Requirements

    The snow model used in the climate change analysis in the 2018 SSA 
report and October 13, 2020, withdrawal document (85 FR 64618) 
projected snow loss out to year 2050 in only two modeling domains 
(Glacier National Park and the central Rocky Mountains) (Service 2018, 
p. 88). Results indicated a decline in spring snow in these areas due 
to climate change was likely, but we were unable to extrapolate those 
projections across the remainder of the North American wolverine's 
breeding range in the contiguous United States. Persistent spring snow 
(greater than or equal to 1 meter on May 1; see Climate Change, below) 
was not identified as an ecological requirement for wolverines, and we 
assumed that if snow was necessary for denning, there would be enough 
spring snowpack in the future to fulfill denning needs.
    Our updated climate analysis reported in the 2023 wolverine SSA 
report addendum projects snow loss out to 2100 across five modeling 
domains that cover a much larger extent of the breeding range in the 
contiguous United States when compared to the 2018 SSA report. In our 
2023 wolverine SSA report addendum, we found declines in spring snow 
due to climate change are likely across the North American wolverine's 
range and predicted losses will be greater in 2100 than in 2050. In 
general, when compared to historical amounts of snow cover, nearly 
every area modeled (except for the Mid-Rockies) sees a decrease in snow 
cover and that decrease becomes larger over time. In the Mid-Rockies, 
snow cover increases in the short term, but as with the other areas, it 
decreases over time.
    New research indicates that areas characterized by persistent 
spring snow are likely important for wolverine survival (e.g., caching 
food) in addition to denning and reproduction. One new study reported 
wolverines cache food year-round, indicating that warmer temperatures 
could impact the ability of wolverines to store food resources by 
decreasing the shelf-life (usability) of cached food, and increasing 
competition from pilferers that benefit from a warmer climate (van der 
Veen et al. 2020, p. 1). Another study found evidence to support a 
functional

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relationship between North American wolverines and persistent spring 
snow that could be explained by the distribution of food, disturbance, 
or mortality risk (Kortello et al. 2019, p. 8).

Connectivity With Canada

    Connectivity with Canada is essential to the long-term viability of 
North American wolverines in the contiguous United States (Cegelski et 
al. 2006, p. 209). In the 2018 SSA report and October 13, 2020, 
withdrawal document (85 FR 64618), we assumed that wolverines could 
move freely between Canada and the United States (Service 2018, p. 
104). We also concluded that trapping of wolverines did not represent a 
barrier to wolverine movement and dispersal along the international 
border (Service 2018, p. 69). Additionally, we concluded that major 
highways did not represent a barrier to wolverine movement (Service 
2018, p. 60).
    In the 2023 wolverine SSA report addendum, we affirm that 
connectivity with Canada is essential to the long-term viability of 
North American wolverines in the lower 48 States. However, our 
understanding of the ability of wolverines to move between Canada and 
the United States in the Rocky Mountains has changed. New research 
found an estimated 41 percent decline in the wolverine population from 
2011-2020 in a portion (7,583,417 acres (ac) (30,689 square kilometers 
(km\2\))) of the southern Canadian Rockies, Purcell Mountains, and 
Selkirk Mountains important for wolverine connectivity with the United 
States; this decline could be attributed to one or more of the 
following causes: trapping, backcountry recreation, human development, 
and food availability (Barrueto et al. 2022, p. 4). In addition, new 
transboundary genetic research indicates the Trans-Canada Highway in 
southern British Columbia is impeding female dispersal from Canada to 
the United States, thereby limiting gene flow and the ability of 
dispersing wolverines to supplement the contiguous U.S. DPS (Sawaya et 
al. 2023, pp. 12, 17).

Genetic Diversity and Adaptive Capacity

    In the October 13, 2020, withdrawal document (85 FR 64618), we 
found there was no available information to indicate that the current 
abundance of the North American wolverine across its range in the 
contiguous United States was at a level that was causing inbreeding 
depression or loss of genetic variation that would affect its ability 
to adapt to changing conditions.
    New transboundary genetic research shows a sharp decline in genetic 
diversity and increasing population fragmentation at the southern 
extent of the North American wolverine's range in western North America 
(Sawaya et al. 2023, p. 17). As a result, there is potential for 
inbreeding given the relatively small population sizes and low levels 
of genetic diversity of wolverines in the contiguous United States, 
especially in the Cascade Mountains of Washington and southern British 
Columbia (Sawaya 2023, pers. comm.); however, inbreeding depression has 
not been observed. New analysis of the North American wolverine's 
adaptive capacity shows that their specialized habitat associations, 
low genetic diversity and population size, narrow ecological niche, low 
tolerance for human disturbance, and slow reproductive rate all 
contribute to the wolverine's relative difficulty in adapting in-place 
to future environmental change (Service 2023, p. 66).

Roads and Development

    We analyzed the effects of roads and development (human 
disturbance) to North American wolverines in the 2018 SSA report 
(Service 2018, p. 62) and determined in our October 13, 2020, 
withdrawal document (85 FR 64618) that impacts to wolverines are small 
and narrow in scope and scale. We did not consider roads and 
development to be an impediment to wolverine movement and gene flow.
    New habitat and landscape genetic research indicates multi-lane 
roads and human development in valley bottoms between core habitats may 
limit dispersal and population connectivity to some extent, especially 
for female wolverines. Connectivity among wolverine habitats appears to 
be particularly sensitive to housing developments (Balkenhol et al. 
2020, p. 797). Also, new research indicates that human disturbance 
(road density) and food availability are major drivers of wolverine 
distribution in winter (Kortello et al. 2019, p. 1). Wolverine density 
and detection probability declined in areas with more human development 
(Barrueto et al. 2022, p. 4). Human development may also have cascading 
impacts of increasing competition from other mesocarnivores that are 
less affected by human disturbance (Frey et al. 2020, pp. 1136-1138; 
Chow-Fraser et al. 2022, p. 6; Milanesi et al. 2022, pp. 10-11).

Winter Recreation

    In our 2018 SSA report and October 13, 2020, withdrawal document 
(85 FR 64618), we concluded that winter recreation is a low-level 
stressor for wolverines in the contiguous United States (Service 2018, 
p. 62). The limited research available at the time indicated some 
avoidance behavior exhibited by wolverines in areas with backcountry 
winter recreation, but not to the extent that we had concerns about 
population-level impacts.
    In the 2023 wolverine SSA report addendum, we provide an updated 
assessment of the effects of winter recreation based on new studies. 
Research indicates winter recreation is negatively associated with 
North American wolverine habitat use, and that winter recreation is 
likely to increase and become more concentrated in the future as snow-
covered areas decline due to climate change (Heinemeyer et al. 2019, p. 
1). A large multi-State analysis of winter recreation impacts in the 
Northern Rocky Mountains was published in 2019, indicating greater 
concern for impacts to wolverines than we found in 2018 and showing a 
negative functional response to the level of recreation exposure within 
their home ranges (Heinemeyer et al. 2019a, pp. 13-14, 17-18). 
Additionally, new research found an incremental loss of wolverines in 
portions of central Idaho where winter recreation impacts are 
increasing (Mack and Hagan 2022, p. 13). Furthermore, forest roads used 
by snowmobilers in the Canadian Rockies were found to have a strong 
negative correlation with wolverine distribution (Kortello et al. 2019, 
p. 10). Wolverine detection probability in protected and non-protected 
habitat of southwestern Canada was found to be strongly and negatively 
correlated with nonmotorized recreation in summer and winter (Barrueto 
et al. 2022, p. 5).

Trapping

    In our 2018 SSA and the October 13, 2020, withdrawal document (85 
FR 64618), we concluded that overutilization does not currently 
represent a stressor to the North American wolverine in the contiguous 
United States at the individual, population, or species level. We also 
concluded that trapping in Canada has been and appears to be 
sustainable, and trapping or harvesting of wolverines along the 
contiguous U.S.-Canada border does not represent a stressor to 
wolverines migrating into the contiguous United States and does not 
represent a barrier to wolverine movement and dispersal along the 
international border (Service 2018, p. 71).
    Legal trapping of wolverines has not occurred in the contiguous 
United States in the past 10 years, and lethal

[[Page 83730]]

incidental trapping of wolverines has been minimal (Service 2023, p. 
38). We expect recent changes to wolf trapping regulations in Idaho and 
Montana to have little effect on wolverines at a population level, as 
long as trapping is done in a manner to limit wolverine bycatch (Idaho 
Department of Fish and Game (IDFG) 2023, in litt., p. 1; IDFG 2022, p. 
40; Montana Fish, Wildlife and Parks (MFWP) 2023, in litt., p. 1; MFWP 
2022, entire). Below, under Overutilization for Commercial, 
Recreational, Scientific, or Educational Purposes, we provide an 
assessment of incidental trapping and the measures States are taking to 
reduce incidental trapping of wolverines.
    Recent research on wolverine trapping in Southern Canada indicates 
that trapping may be having more of a negative effect on wolverine 
populations in Canada than previously thought (Kortello et al. 2019, 
pp. 1, 10; Mowat et al. 2020, entire; Barrueto et al. 2020, p. 296; 
Barrueto et al. 2022, entire). Unsustainable trapping levels in Canada 
could limit dispersal of individuals into the contiguous United States, 
where the dispersal of wolverines from Southern Canada is vital to the 
genetic and demographic health of the U.S. population (Sawaya 2023, 
pers. comm.).

Summary of Comments and Recommendations

Comments on the 2013 Proposed Listing Rule

    Upon publication of our February 4, 2013, proposed rule to list the 
DPS of North American wolverine occurring in the contiguous United 
States as a threatened species (78 FR 7864), we opened a 90-day public 
comment period, ending May 6, 2013. After we withdrew the proposed 
rule, on October 18, 2016 (81 FR 71670), we again opened a public 
comment period on our 2013 proposed listing rule; that comment period 
was open for 30 days, ending November 17, 2016. At both times, we 
contacted appropriate Federal and State agencies, scientific experts 
and organizations, Tribes, and other interested parties and invited 
them to comment on the 2013 proposed listing rule. Many of the comments 
we received from State agencies during our 2016 reopened comment period 
(81 FR 71670) were similar to those we received during the initial 2013 
public comment period (78 FR 7864). All substantive information 
provided during both comment periods on our 2013 proposed listing rule 
has either been incorporated directly into this final determination or 
is addressed below.
    Below, we present the comments received on the 2013 proposed 
listing rule and a summary of our responses as presented in the October 
13, 2020, withdrawal document (85 FR 64618). We also provide updated 
responses to several of the comments based on new information presented 
in the 2023 wolverine SSA report addendum and this final rule. Comments 
are numbered below as they were numbered in the October 13, 2020, 
withdrawal document (85 FR 64618). Several of the comments and 
responses from the October 13, 2020, withdrawal document did not 
require revision, and they are incorporated here by reference; those 
comments with responses that remain the same are comments 6, 7, 9, 11, 
13, 20, 21, 22, 23, and 24 (85 FR 64618 at 64622-64626).

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 snowpack.
    Our 2020 Response Summarized: Our climate assessment in the 2018 
wolverine SSA report and October 13, 2020, withdrawal document focused 
on the impact of climate change to denning conditions for wolverines. 
We stated 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. 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 (on April 30/May 1). We 
referenced a climate analysis that included two regions, Glacier 
National Park and Rocky Mountain National Park. Details of this climate 
analysis are presented in Ray et al. (2017) and are summarized in the 
2018 SSA report. Climate models in Ray et al. (2017) 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). Model projections from Ray et al. (2017) 
indicate significant areas (several hundred square kilometers (km\2\)/
square miles (mi\2\) for each study area) of future snow (greater than 
0.5 meters (m) (20 inches (in)) in depth) are likely 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.
    Our 2023 Response: Our assessment of climate change impacts to 
North American wolverines in the 2023 wolverine SSA report addendum, 
and applied in this final rule, evaluates the impact of climate warming 
and changes in snowpack on various aspects of wolverine ecology, not 
just denning habitat (see Climate Change, below). We now consider 
habitats characterized by the presence of persistent spring snow for 
survival and reproduction to be a physical and ecological requirement 
for wolverines in the contiguous United States (see Life-History Needs, 
below). New evidence from around the world reinforces that snow--
especially persistent spring snow--is an important predictor of broad-
scale wolverine distribution and density (Aubry et al. 2023, pp. 15-16; 
Carroll et al. 2020, p. 8; Fisher et al. 2022, p. 10; Glass et al. 
2021, entire; Mowat et al. 2020, p. 220). Snow cover appears to 
influence wolverine dispersal and resulting genetic structure 
(Balkenhol et al. 2020, pp. 798-799). Warming future conditions could 
make caching food more difficult for wolverines year-round (Van der 
Veen et al. 2020, pp. 8-10). Climate change also has the potential to 
exacerbate the impacts of other stressors, including effects from 
roads, winter recreational activity, development, low genetic 
diversity, and small populations (see Threats, below). Wolverines have 
denned outside of spring snowpack in the boreal forests of Canada and 
Scandinavia; however, the importance of spring snow for denning may 
vary among areas depending on the abundance of alternative den site 
structures, competitors, and food resources (Persson et al. 2023, p. 
5810). Furthermore, there is no evidence that North American wolverines 
have denned in areas outside of spring snowpack in their alpine 
habitats in the contiguous United States. In light of this, we do not 
expect North American wolverines to continue to have the same or better 
resiliency in the contiguous United States in the future when cold and 
snowy conditions are expected to decrease, with spring snowpack 
decreasing as much as 50 percent in some areas. Although we are not 
seeing deleterious effects of climate change on the contiguous U.S. 
population of North American wolverines currently, we expect future 
impacts at the population level. For further detail, see the discussion 
under Climate Change, below.
    (2) Comment: We received several public comments during our request 
for

[[Page 83731]]

information claiming that low population size (and small effective 
population size) warrant listing of the North American wolverine as 
threatened or endangered.
    Our 2020 Response Summarized: We stated that 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 that time (and still today), 
the only estimate of the number of wolverines that currently occupy the 
contiguous United States is the often-cited population estimate of 318 
wolverines (range: 249-926) in the contiguous United States. This 
estimate was derived from habitat modeling presented in Inman et al. 
(2013). That publication also provided a modeled estimate of potential 
wolverine capacity in the contiguous United States of 644 wolverines 
(range: 506-1881). We also reported the preliminary results from the 
Western States Wolverine Conservation Project (WSWCP) occupancy study 
in four western States (Idaho, Montana, Washington, and Wyoming) and 
from a pilot occupancy study in Wyoming (2015-2016) (Service 2018, 
appendix B). Preliminary analysis of the study results indicated an 
average estimated probability of occupancy of 0.42, suggesting that 
wolverines used nearly half of all sites during the study period (MFWP 
2017, pers. comm.). Although the sum of these reports cannot confirm 
the previous estimate 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.
    We also discussed the estimated effective population size 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). We stated that the analysis missed two wolverine 
subpopulations as well as individuals, which would underestimate the 
results for this type of analysis. We went on to discuss the apparent 
connectivity between wolverines in the contiguous United States and 
Canada, and we considered the contiguous United States to be 
genetically continuous with wolverines in adjacent Canadian provinces. 
We concluded that 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.
    Our 2023 Response: The best available estimate of effective 
population size for the wolverine in the Northern Rocky Mountains 
continues to be 35 (credible interval = 28-52) (Schwartz et al. 2009, 
p. 3226). We estimated the effective population size of wolverines in 
the North Cascades to be four (Service 2023, p. 27). Overall, the 
effective population size estimates of wolverines in the contiguous 
United States are small compared to conservation guidelines, and the 
contiguous U.S. DPS of North American wolverines appear to be 
vulnerable to inbreeding and loss of genetic diversity when considered 
in isolation. However, only one or two effective migrants per 
generation (i.e., the number of migrants that reproduce at the same 
rate as residents) are likely needed to achieve genetic population 
connectivity and maintain existing levels of genetic diversity 
(Cegelski et al. 2006, p. 209).
    At the time we published the October 13, 2020, withdrawal document 
(85 FR 64618), we considered the contiguous U.S. population to be 
genetically continuous with Canada. We now know that wolverine 
populations in southern British Columbia and Alberta near the 
transboundary interface are less genetically connected to the 
contiguous United States than we found in our 2018 SSA. New information 
has revealed that female wolverines appear to avoid crossing major 
roadways, including the Trans-Canada Highway (Highway 1) and the 
Crowsnest Highway (Highway 3) in southern British Columbia (Sawaya et 
al. 2023, pp. 11-14). Substantially lower mitochondrial DNA diversity 
in the United States, as compared to mitochondrial DNA diversity in 
Canada, is consistent with the nuclear DNA signals of limited 
contemporary female gene flow between the countries and the wolverine's 
relatively recent recolonization at the southern edge of their range 
(Sawaya et al. 2023, p. 17). See ``Gene Flow Between the United States 
and Canada'' and ``Population Structure and Gene Flow Within Canada,'' 
below, for more detail. Given the new information on limited gene flow 
with Canada and the potential impacts of climate change to future 
dispersal, the low effective population size in the contiguous U.S. 
population of North American wolverines is a concern to future 
population viability.
    (3) Comment: We received several public comments during our request 
for information claiming that the North American wolverine faces 
threats from indiscriminate trapping in the contiguous United States, 
or are negatively impacted by incidental trapping.
    Our 2020 Response Summarized: In our October 13, 2020, withdrawal 
document (85 FR 64618), we stated that trapping or hunting of 
wolverines was not allowed in any State within the range of the 
wolverine in the contiguous United States, and we presented the legal 
protections afforded to wolverines in each State. We summarized what we 
knew at the time about incidental trapping. In the wolverine SSA 
report, we provided 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. We noted that regulated trapping and 
hunting of wolverines occurs in parts of Alaska and Canada, and appears 
to be sustainable based on population and density estimates.
    Our 2023 Response: Legal trapping of wolverines has not occurred in 
the contiguous United States in the past 10 years. Wolverine trapping 
remains closed throughout the western United States, and wolverines 
have retained various protected status designations in the States 
within their current U.S. range (Service 2023, table 10). Therefore, 
legal direct trapping is no longer a stressor on wolverines in the 
contiguous United States. In the past 10 years, lethal incidental 
trapping of wolverines has been minimal (approximately 1 to 2 animals 
per year or fewer), primarily occurring in Idaho and Montana (see 
Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes, below). New information suggests that recent 
overharvest from trapping has occurred in southern Canada in areas that 
could provide dispersing individuals to the contiguous United States 
(Mowat et al. 2020, entire). Trapping in southern Canada appears to 
have had a more negative effect on wolverine populations in Canada than 
previously thought. Legacy effects of recent unsustainable trapping 
levels in a portion of the southern Rocky Mountains of Canada could 
limit dispersal of individuals into the contiguous United States in an 
area where wolverine connectivity between the United States and 
southern Canada is vital to the genetic and demographic health of the 
U.S. wolverine population. See Overutilization for Commercial, 
Recreational, Scientific, or Educational Purposes and Provisions of the 
Interim 4(d) Rule, below, for further details.

[[Page 83732]]

    (4) Comment: We received several public comments identifying 
potential threats to wolverines from winter recreation activities, such 
as snowmobiling and backcountry skiing.
    Our 2020 Response Summarized: When we published our October 13, 
2020, withdrawal document (85 FR 64618), there was little information 
on the effect of winter recreation on wolverines. We received a final 
report of a multiyear study on the effects of winter recreation on 
wolverines (Heinemeyer et al. 2017, entire) in mid-December 2017, and 
the results of this study were published (Heinemeyer et al. 2019a, 
entire) prior to the publication of our 2020 withdrawal document. The 
study found that wolverines were displaced from habitat by winter 
recreation but 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. 2019a, p. 16). 
The study described habitat selection as complex for female wolverines 
and stated that habitat selection 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. 2019a, p. 
16). This study did not assess demographic effects, fitness effects, or 
population-level effects of winter recreation on wolverines (Heinemeyer 
et al. 2019a, pp. 17, 19).
    Our 2023 Response: There are multiple recent studies that indicate 
wolverines are negatively affected and displaced (at least temporarily) 
by various types of backcountry winter recreation (Barrueto et al. 
2022, entire; Heinemeyer et al. 2019a, entire; Heinemeyer et al. 2019b, 
entire; Kortello et al. 2019, entire; Mack and Hagen 2022, entire; 
Regan et al. 2020, entire). The effect of winter recreation activity 
(of concern due to potential impacts to denning and survival), in 
isolation, represents a low threat to wolverines in the contiguous 
United States at the population level. However, in combination with 
other threats, including decreased snow availability (see Climate 
Change, below) and increased overlap with winter recreationalists in 
the future due to climate change, winter recreation could negatively 
affect wolverine population resilience in the future. See Disturbance 
Due to Winter Recreational Activity, below, for further details.
    (5) Comment: We received public comments claiming that wolverines 
are dependent on deep snow for survival and expressing concern for 
future changes in snowpack due to the effects of climate change.
    Our 2020 Response Summarized: Our response to this comment in our 
October 13, 2020, withdrawal document (85 FR 64618) focused on snow 
availability for denning and the wolverine's ability to cope with 
changing snow conditions in the denning context. We stated 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 the contiguous United States in areas where 
wolverines are known to den at levels that will continue to support 
wolverines. 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.
    In our evaluation of the effects of climate change to snowpack (see 
Service 2018, pp. 73-99), 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. 
These dates are more relevant to the North America wolverine's life-
history needs. We also modeled the depth of ``significant'' snow (0.5 m 
(20 in)) on these dates. We found that large areas (several hundred 
km\2\/mi\2\ for each study area) of future snow cover (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.
    Our 2023 Response: As discussed above in our response to (1) 
Comment, the wolverine is a snow-adapted species that utilizes cold and 
snowy habitats for multiple aspects of its life history. To inform our 
assessment of the wolverine's status in the contiguous United States, 
we updated our previous climate change analysis, the details of which 
are summarized in the wolverine SSA report addendum (Service 2023, pp. 
47-60). Our analysis focuses on the expected loss of snowpack out to 
2100 in five modeling domains that overlap with occupied and potential 
wolverine habitat in the contiguous United States across latitudinal, 
longitudinal, and elevation gradients. The Service chose a snow depth 
threshold of greater than or equal to 1 m (3.3 ft) to represent 
significant snow cover on May 1, which provides a more conservative 
estimate than was used in the 2018 SSA (i.e., greater than or equal to 
0.5 m (20 in.) on May 1). This updated analysis shows that cold and 
snowy conditions at high elevations are expected to decrease, with 
spring snowpack at denning elevations decreasing as much as 50 percent 
in some areas. As a result, we expect wolverine population resiliency 
in the contiguous United States to decrease in the future. For more 
information see Climate Change, below.
    (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 2020 Response Summarized: We acknowledged that some members of 
the public supported our decision to withdraw our proposed rule to list 
the North American wolverine occurring in the contiguous United States 
as a threatened species under the Act. In the wolverine SSA report 
(Service 2018, appendix G), we provided 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. Trapping or hunting of wolverines was prohibited in the 
contiguous United States when our October 13, 2020, withdrawal document 
(85 FR 64618) published.
    Our 2023 Response: We appreciate the regulatory protections and 
management measures our State wildlife agency partners and Federal 
resource management agencies have enacted to conserve the North 
American wolverine and its habitat (Service 2018, appendix G). However, 
we have determined that the contiguous U.S. DPS of North American 
wolverine meets the Act's definition of a threatened species as 
described in this rule due to future threats, including the reduction 
in spring snowpack from climate change. This determination is not a 
reflection on the adequacy of State management or the capability of 
States to manage the species but rather an acknowledgement of the 
serious threat posed to the species

[[Page 83733]]

by climate change. Along with the listing, we are finalizing an interim 
4(d) rule that will promote conservation of the contiguous U.S. DPS of 
North American wolverine by encouraging management of the landscape by 
our partners in ways that meet the conservation needs of the wolverine. 
The provisions of this 4(d) rule provide one of many tools we will use 
to promote the conservation of the contiguous U.S. DPS of North 
American wolverine.
    (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 restricted 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 
associated roads, and effects of snowmobile traffic (habitat 
fragmentation and pollution, and change in behavior).
    Our 2020 Response Summarized: We found that 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) were low based on our evaluation of the 
best available information at the time in relation to current and 
potential future conditions for the North American wolverine occurring 
in the contiguous United States and in the context of the attributes 
that affect the needs of the DPS (Service 2018, p. 103). Thus, we 
determined that the North American wolverine in the contiguous United 
States did not meet the definition of an endangered species or a 
threatened species under the Act.
    Our 2023 Response: Our 2018 wolverine SSA report and 2023 SSA 
report addendum provide a thorough assessment of the threats affecting 
the North American wolverine in the contiguous United States. New 
information related to the threats affecting the contiguous U.S. DPS of 
the North American wolverine have led us to a different conclusion than 
the one we presented in our October 13, 2020, withdrawal document (85 
FR 64618). In this final rule, we examine the best available 
information about threats to the wolverine, including effects from 
roads, disturbance due to winter recreational activity, other human 
disturbance, effects from wildland fire, disease, predation, 
overutilization (trapping), genetic diversity, small population 
effects, and climate change, including the cumulative effects of these 
threats. See Summary of Biological Status and Threats, below, for a 
complete discussion of threats affecting the DPS. After assessing the 
best available information, we conclude that the contiguous U.S. DPS of 
the North American wolverine is not currently in danger of extinction 
but is likely to become in danger of extinction within the foreseeable 
future throughout all of its range.
    (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 2020 Response Summarized: We reevaluated wolverines occurring 
in the contiguous United States under our Policy Regarding the 
Recognition of Distinct Vertebrate Population Segments Under the 
Endangered Species Act (DPS policy; 61 FR 4722, February 7, 1996). See 
Distinct Population Segment in the October 13, 2020, withdrawal 
document (85 FR 64618 at 64628-64631) for more information. We provided 
our analysis of the status of wolverines in the contiguous United 
States under Determination of Species Status in the October 13, 2020, 
withdrawal document (85 FR 64618 at 64645-64647). The topic of denning 
behavior is discussed in the wolverine SSA report (see ``Use of Dens 
and Denning Behavior'' under Reproduction and Growth in the wolverine 
SSA report (Service 2018, pp. 23-28)). For our analysis of the effects 
of climate change to North American wolverines and denning habitat, see 
``Climate Change and Potential for Cumulative Effects'' in the October 
13, 2020, withdrawal document (85 FR 64618 at 64642-64644).
    Our 2023 Response: In this final rule, we provide our revised 
evaluation of discreteness and significance under our DPS policy of the 
segment of the North American wolverine occurring in the contiguous 
United States considering new information available since the 
publication of our October 13, 2020, withdrawal document (85 FR 64618). 
We also explain how new information has led us to a different 
determination from previous DPS analyses. The analysis contained in 
this rulemaking supersedes and replaces any previous DPS analysis for 
the segment of the North American wolverine occurring in the contiguous 
United States. We conclude that the population of wolverines in the 
contiguous United States is discrete and significant in relation to the 
remainder of the species in North America. For more information, see 
Distinct Population Segment Analysis for Wolverine in the Contiguous 
United States, below.
    The wolverine population in the contiguous United States is 
expected to decrease in resiliency, redundancy, and representation in 
the foreseeable future. The best available information suggests that 
habitat loss as a result of climate change, and the resulting 
exacerbating effect on other stressors, are likely to decrease the 
viability of wolverines in the contiguous United States within this 
century (see ``Summary of Future Condition'' and Determination of North 
American Wolverine's Status, below). Our review of the best scientific 
and commercial data available indicates that the contiguous U.S. DPS of 
the North American wolverine meets the Act's definition of a threatened 
species.
    We acknowledge the precise causal mechanism(s) for the apparent 
association of wolverine distribution with persistent spring snow are 
not yet clear. The association could involve the importance of snow for 
denning or other aspects of the species' biology and ecology. We 
address uncertainties under Areas of Uncertainty for Wolverine Habitat 
Needs, below. That said, we know that wolverines are a species that is 
adapted to, and has a strong preference for, cold and snowy conditions 
and that these conditions will be reduced in the future. The commenter 
is accurate in that climate models do not predict a complete loss of 
snow within the North American wolverine's range in the contiguous 
United States. However, we expect climate change to reduce snowpack in 
areas used by wolverines by as much as 50 percent in some places (see 
our analysis under Climate Change, below). We conclude increasing 
temperatures and decreasing snowpack have the

[[Page 83734]]

largest potential to influence the population viability of the 
contiguous U.S. DPS of the North American wolverine in the future.
    Regarding winter recreation, new information supports our 
understanding that some forms of winter recreation, backcountry 
motorized recreation especially, have the potential to negatively 
impact wolverines. See our response to (4) Comment, above, and 
Disturbance Due to Winter Recreational Activity, below, for further 
details.

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 Act's 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 2020 Response Summarized: 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 studies of 
wolverines.
    We used the best available scientific information to provide a 
detailed description of the North American wolverine's life history and 
ecology, including a detailed discussion of wolverine denning habitat 
and behavior. We conducted an analysis to assess the current population 
status. Conservation measures and regulatory mechanisms relative to the 
North American wolverine were also provided in the wolverine SSA 
report. This information was used to evaluate the current and future 
conditions of the DPS. We evaluated results from a fine-scale analysis 
of the potential effects of climate change to future snowpack 
conditions and found significant areas of snow (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 did not 
warrant listing as threatened or endangered under the Act in 2020.
    Our 2023 Response: We appreciate the commitment of the Tribal 
nations to further our knowledge of this unique species. We have 
gathered the best available information on North American wolverines 
and used this information to assess the current and future population 
status of wolverines in the contiguous United States.
    Regarding winter recreation, see our response to (4) Comment, 
above, and Disturbance Due to Winter Recreational Activity, below, for 
further details.
    Regarding the effects of climate change to North American 
wolverines, see our response to (1) Comment, above, and Climate Change, 
below. We conclude that the contiguous U.S. DPS of the North American 
wolverine is not currently in danger of extinction but is likely to 
become in danger of extinction within the foreseeable future throughout 
all of its range.
    (15) Comment: We received comments from one Tribe whose 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 2020 Response Summarized: We appreciate the perspective 
provided regarding the importance of the North American 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. The best available scientific 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 DPS. Based on the best available information, we 
determined that the North American wolverine in the contiguous United 
States did not warrant listing as endangered or threatened under the 
Act in 2020.
    Our 2023 Response: Information previously provided by the Tribe was 
considered in the 2018 SSA report. We include new and updated 
scientific information in the 2023 wolverine SSA report addendum, 
including information on the current conditions (i.e., potential 
stressors, including winter recreation) and future conditions (e.g., 
effects of climate change) of the DPS. Based on the best available 
information, we now determine that the contiguous U.S. DPS of the North 
American wolverine meets the Act's definition of a threatened species.

State Agency Comments

    In our October 13, 2020, withdrawal document (85 FR 64618), we also 
addressed the extensive comments from several western States, including 
previously submitted comments in response to the February 4, 2013, 
proposed listing rule (78 FR 7864) as well as additional comments 
submitted in response to our October 18, 2016, document that reopened 
the public comment period on the 2013 proposed listing rule (81 FR 
71670). 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 February 4, 
2013, proposed listing 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 February 4, 
2013, proposed listing rule.
    Our 2020 Response Summarized: In preparing the 2018 SSA report for 
the North American wolverine, our foundational science document for 
informing the October 13, 2020, withdrawal (85 FR 64618), we reviewed 
available reports and peer-reviewed literature, incorporated survey 
information for the purpose of preparing updated maps of the known 
current and historical occurrences of the North American wolverine, and 
contacted species experts to collect additional unpublished 
information. We evaluated the appropriate analytical tools to

[[Page 83735]]

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 2018 SSA report, the draft wolverine SSA 
report was submitted for peer review to four independent peer reviewers 
and submitted to our Federal, State, and Tribal partners for scientific 
review. We incorporated the results of these reviews in the 2018 
wolverine SSA report, as appropriate.
    We recognized that climate trends and future (2055 and later) 
climate model projections indicated warming temperatures for much of 
western North America, and changes to snowpack conditions. Our 
assessment of climate change impacts indicated 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) would persist on May 1 at 
elevations currently used by wolverines for denning. This was true, on 
average, across the range of climate models used out to approximately 
year 2055.
    Our 2023 Response: In the 2023 wolverine SSA report addendum, we 
expanded upon our climate analysis from the 2018 SSA report. Both SSA 
documents went through an independent, scientific peer review process. 
The assessment of the climate modeling results, presented below under 
Climate Change, and applied in the ``Summary of Future Condition'' 
discussion, replaces and supersedes the analysis of modeling results 
presented in the February 4, 2013, proposed listing rule (78 FR 7864) 
and the October 13, 2020, withdrawal document (85 FR 64618). We 
acknowledge there are uncertainties around the nature of the 
wolverine's relationship with cold and snowy conditions (see Areas of 
Uncertainty for Wolverine Habitat Needs, below). Cold and snowy 
conditions at high elevations favored by wolverines in the contiguous 
United States are expected to decrease, with spring snowpack at denning 
elevations decreasing as much as 50 percent in some areas.
    (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 2020 Response Summarized: In the October 13, 2020, withdrawal 
document (85 FR 64618), we referred to our response to (2) Comment for 
a discussion of effective population size (85 FR 64618 at 64620). 
Regarding recent occurrences of wolverines in the contiguous United 
States, we noted that wolverines had recently been found in areas where 
they were once extirpated in the contiguous United States. See 
``Population Abundance and Density'' in the October 13, 2020, 
withdrawal document (85 FR 64618 at 64634-64636) for more information.
    Our 2023 Response: The best available estimate of effective 
population size for the Northern Rocky Mountains continues to be that 
provided by Schwartz et al. 2009 (p. 3226): 35 (credible interval = 28-
52). We estimated the effective population size of wolverines in the 
North Cascades to be four (Service 2023, p. 27). We are not aware of 
any other estimates of the effective population size of North American 
wolverines in the contiguous United States. See also our response to 
(2) Comment, above, and Effective Population Size in the Contiguous 
United States, below, for more information.
    We have gathered updated occurrence information in our 2023 
wolverine SSA report addendum (Service 2023, figure 2). We acknowledge 
that there are recent occurrences of wolverines in the western United 
States in areas where they have not been reported for years or very 
rarely (California, Colorado, Oregon, and Utah). These occurrences 
outside of the known breeding distribution are encouraging, but there 
is no evidence of breeding population expansion into California, 
Colorado, Oregon, and Utah.
    (18) Comment: We received comments from several western States 
presenting clarifications or updates to incidental trapping events and 
trapping regulations.
    Our 2020 Response Summarized: We noted that trapping or hunting of 
wolverines was not allowed in any western State (with the exception of 
Alaska, which was not included in the DPS in our February 4, 2013, 
proposed listing rule (78 FR 7864)). Legal protections for wolverines 
are codified in western State laws and regulations concerning hunting 
and trapping. Since 2013, there has been a zero quota for trapping or 
harvest of wolverines in Montana. We described the documentation of 
incidental trapping of wolverines in the contiguous United States (as 
recently as December 2017) and noted that not all events resulted in 
mortality. We acknowledged that both Idaho and Montana are implementing 
trapper education programs to minimize nontarget wolverine captures.
    Our 2023 Response: We gathered updated information from States 
within the North American wolverine's range about incidental trapping, 
trapping regulations, and measures taken by States to prevent 
incidental trapping of wolverines. Lethal incidental trapping of 
wolverines has been minimal (1 to 2 animals per year), primarily 
occurring in Idaho and Montana. In the Overutilization for Commercial, 
Recreational, Scientific, or Educational Purposes discussion, below, we 
provide an assessment of incidental trapping and the measures States 
are taking to reduce incidental trapping of wolverines.
    (19) Comment: Several States provided comments in response to our 
February 4, 2013, proposed listing rule (78 FR 7864) and our October 
18, 2016, reopening of the public comment period (81 FR 71670) 
indicating their disagreement with our determination of a wolverine DPS 
for the contiguous United States. Specifically, some commenters stated 
that the criteria of significance should be reevaluated, noting that 
the February 4, 2013, proposed listing 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 February 4, 2013, 
proposed listing 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. The commenter pointed out that 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. The commenter 
asserted that our characterization in the February 4, 2013, proposed 
listing rule of ``liberal''

[[Page 83736]]

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.
    Our 2020 Response Summarized: In light of the updated analysis and 
new information included in the 2018 wolverine SSA report, we 
reevaluated wolverines in the contiguous United States under our DPS 
policy. We concluded that the population of wolverines in the 
contiguous United States was not discrete in relation to the remainder 
of the species in North America. As a result, in 2020, the population 
of wolverines in the contiguous United States was not a listable entity 
under section 3(16) of the Act. See Distinct Population Segment in the 
October 13, 2020, withdrawal document (85 FR 64618 at 64627-64631) for 
more information.
    Our 2023 Response: As stated above, in this final rule we provide 
our revised evaluation of discreteness and significance under the DPS 
policy of the segment of the North American wolverine occurring in the 
contiguous United States considering new information. We also explain 
how new information has led us to different conclusions from previous 
DPS analyses. The analysis contained in this rulemaking supersedes and 
replaces any previous DPS analysis for the segment of the North 
American wolverine occurring in the contiguous United States.
    Regarding the commenter's concern with the significance analysis, 
we have determined, as we did in the February 4, 2013, proposed listing 
rule, that there is evidence that the loss of the wolverine in the 
contiguous United States would result in a significant gap in the range 
of the taxon. Based upon the loss of approximately 58,998,140 acres 
(238,757 km\2\) of high-quality wolverine habitat from the southern 
extent of the range and the adaptive potential that part of the range 
provides against oncoming climate change impacts, and the 12-degree 
latitudinal gap in the wolverine's range that would result if the U.S. 
population was lost, we determine that the loss of the contiguous U.S. 
wolverine population would result in a significant gap in the range of 
the taxon. Thus, the DPS meets the definition of significant in our DPS 
policy. For more information see Analysis of Significance, below.
    Regarding the commenter's assertion that wolverines in the 
contiguous United States are connected to Canada, which relates to the 
discreteness analysis of our DPS policy, we do not consider wolverines 
in the contiguous United States to be genetically or morphologically 
discontinuous from wolverines in Canada (McKelvey et al. 2014, entire; 
Pilgrim and Schwartz 2018, entire; Sawaya et al. 2023, entire). 
Therefore, wolverines in the contiguous United States are not discrete 
based on marked separation from other populations of the same taxon. 
However, we determined that the wolverine meets the discreteness 
criterion in our DPS policy (61 FR 4722; February 7, 1996), as 
delimited by the international boundary with Canada and given 
differences in control of exploitation, conservation status, and 
regulatory mechanisms that are significant in light of section 
4(a)(1)(D) of the Act. See Analysis of Discreteness, below, for more 
information.
    Finally, regarding the commenter's point about our characterization 
in the February 4, 2013, proposed listing rule of trapping in Canada 
versus the contiguous United States, we have considered updated 
trapping information in our DPS analysis. New information available 
since the publication of our October 13, 2020, withdrawal document (85 
FR 64618) indicates that overharvest from trapping in Canada was likely 
causing more of an impact than previously thought. Recent studies show 
that harvest levels in portions of southeastern British Columbia and 
southwestern Alberta were unsustainable and causing population declines 
(Mowat et al. 2020, entire; Barrueto et al. 2022, entire) and could 
negatively impact movement of individuals from Canada to the contiguous 
United States (Sawaya 2023, pers. comm.). We now conclude that the 
differences between Canada and the United States in control of 
exploitation are significant in light of section 4(a)(1)(D) of the Act 
and the wolverine population in the contiguous United States meets the 
DPS policy's standard for ``discreteness.'' See Analysis of 
Discreteness, below, for more information.
    We conclude that the population of wolverines in the contiguous 
United States is discrete and significant in relation to the remainder 
of the species in North America. For our complete DPS analysis, see 
Distinct Population Segment Analysis for Wolverine in the Contiguous 
United States, below.

Comments Received in Response to Our November 23, 2022, Publication

    As stated above, on November 23, 2022, we published a document in 
the Federal Register (87 FR 71557) soliciting new information to update 
the wolverine SSA so that we could reevaluate whether the North 
American wolverine occurring in the contiguous United States is a 
distinct population segment and, if so, whether the distinct population 
segment meets the definition of an endangered or threatened species 
under the Act. This document also notified the public that the February 
4, 2013, proposed listing rule (78 FR 7864) had been reinstated as a 
result of court action. In response to the November 23, 2022, 
publication, we received additional information including survey 
results, reports, documented mortalities, management efforts, and 
recent wolverine literature that we evaluated and incorporated as 
appropriate into our wolverine SSA report addendum. Although not 
requested, we also received comments from submitters on topics related 
to determinations regarding wolverine, including whether the wolverine 
should or should not be listed as an endangered or threatened species 
under the Act. The comments we received are similar to those we present 
and respond to above.

Peer Reviewer Comments on the 2023 Wolverine SSA Report Addendum

    We received comments from three peer reviewers on the draft 
wolverine SSA report addendum. We reviewed all comments we received 
from the peer reviewers for substantive issues regarding the 
information contained in the wolverine SSA report addendum, as well as 
any new information. The peer reviewers generally provided additional 
references, clarifications, and suggestions, including further 
definitions of some of the terms used in the wolverine SSA report 
addendum. We updated the wolverine SSA report addendum based on the 
peer reviewers' comments, including revising some of our adaptive 
capacity scores, clarifying specific points where appropriate, and 
adding additional details and suggested references where needed. Peer 
reviewer comments are addressed in the following summary.
    (PR1) Comment: Regarding our climate change analysis, one peer 
reviewer did not agree with our initial characterization of the shared 
socioeconomic pathway (SSP) 5-8.5 emissions scenario as worst case, and 
stated there are possible scenarios that could be more extreme. They 
also recommended the wolverine SSA report addendum more clearly point 
out the uncertainty around the climate models and emissions scenarios 
by stating the scenarios are representative of a large

[[Page 83737]]

portion of plausible outcomes, but not all.
    Our Response: We addressed the peer reviewer's concern by removing 
mention of likelihood when discussing specific emissions scenarios. We 
also modified the text to include the latest guidance from the White 
House Office of Science and Technology Policy on Selecting Climate 
Information to Use in Climate Risk and Impact Assessments (OSTP 2023, 
entire), which recommends using SSP5-8.5 as an upper bounding scenario. 
We applied SSP5-8.5 as the upper bound to estimate future snow cover 
available for wolverines within the selected domains.
    (PR2) Comment: A peer reviewer questioned why we used the SSP2-4.5 
and SSP5-8.5 emissions scenarios for our future condition analysis. 
They suggested we use SSP1-1.9 instead of SSP2-4.5 since it is the 
opposite extreme of SSP5-8.5.
    Our Response: For our future analysis, we used SSP2-4.5 because 
that emissions scenario is closest to the current emissions trajectory 
we are on now, which provides a plausible lower boundary estimate of 
future snow cover available for North American wolverines. The 
Intergovernmental Panel on Climate Change (IPCC) has recently deemed 
our ability to limit warming to 1.5 [deg]C (2.7 [deg]F) (SSP1-1.9) as 
``impossible'' with no or limited overshoot in its 2022 gap analysis 
(Riahi et al. 2022, p. 298). Scenario SSP5-8.5 reflects a no-emissions 
mitigation policy, which provides a plausible upper boundary estimate 
of available future snow cover.
    (PR3) Comment: A peer reviewer was concerned that the wolverine SSA 
report addendum did not list snow as an important attribute when 
studies have shown dens are concordant with spring snow coverage. The 
peer reviewer disagreed with our reasoning for excluding snow, which 
was because we do not know how it impacts survival and reproduction, 
and stated we should also remove food habits, physical features, and 
home range size since it is not clear how any of these impact survival 
and reproduction. They believe the case for snow is much stronger than 
any of these other factors.
    Our Response: We considered the information provided and addressed 
the peer reviewer's concern by updating the wolverine SSA report 
addendum to include snow as an important attribute of wolverine 
habitat.
    (PR4) Comment: One peer reviewer was concerned about the use of 
spring snow cover for distribution. They questioned our use of the term 
``persistent spring snow'' and the May 15 end date that is often 
associated with the term. The peer reviewer recommended analyzing snow 
cover between February and March, when young are newborn and most in 
need of thermal cover in natal dens. The reviewer believed that any 
analysis of climate change effects at those more critical times for 
denning would not likely show impacts.
    Our Response: We used the term ``persistent spring snow'' in the 
wolverine SSA report addendum because it is a term frequently used in 
the scientific literature for wolverines and appears to be correlated 
to the wolverine's circumpolar distribution. Snow model outputs for May 
1 are presented in the 2023 wolverine SSA report addendum. May 1 was 
used based on previous studies documented in the 2018 SSA (Service 
2018, p. 26), indicating wolverine den site abandonment generally 
occurs before May 1. We acknowledge that young kits are in natal dens 
usually from mid-February to mid-March, so the use of May 1 snow 
projections is a conservative approach, but one which is consistent 
with the literature.
    As described in the wolverine SSA report addendum, there are a 
number of hypotheses for why wolverines prefer cold and snowy habitats, 
and not all of them are limited to denning (i.e., easier to get food, 
more food caching sites, etc.). These things could be important for 
adults throughout the breeding cycle or for juveniles as they become 
more independent from their mothers. We also discuss the possibility of 
other factors that are correlated to persistent spring snow, such as 
low temperatures (also analyzed in Copeland et al. 2010, entire), being 
the causal mechanisms for the observed relationship. In the wolverine 
SSA report addendum, we acknowledge wolverines have been documented 
denning in areas without persistent spring snow (Aronsson and Persson 
2017, p. 266; Copeland et al. 2010, pp. 240-242; Fisher et al. 2022, p. 
8; Jokinen et al. 2019, pp. 6-8; Persson et al. 2023, entire; Webb et 
al. 2016, pp. 1466-1467); however, this phenomenon appears to be 
associated with cold, high-latitude boreal or arctic forests rather 
than the alpine habitats used by wolverines in the contiguous United 
States. In the contiguous United States, there is no evidence that 
wolverines have denned in areas without persistent spring snow.
    (PR5) Comment: One peer reviewer recommended including potential 
ways wolverines could adapt their denning behavior or use smaller or 
shallower patches of snow for denning in response to effects from 
climate change.
    Our Response: We added language to the wolverine SSA report 
addendum to address this comment and we also included additional text 
that snow may be important for more than just denning. As stated above, 
there is no evidence that wolverines have denned in areas without 
persistent spring snow in the contiguous United States.
    (PR6) Comment: A peer reviewer pointed out that future recreation 
will not just increase due to an increase in the human population, but 
also because snow-dependent recreational activities will be constrained 
to a smaller area that still contains quality snow in the future.
    Our Response: We included text in the wolverine SSA report addendum 
reflecting the reviewer's comment.
    (PR7) Comment: One peer reviewer suggested adding Colorado's 
wolverine reintroduction plan to the wolverine SSA report addendum as a 
voluntary conservation measure.
    Our Response: We updated the wolverine SSA report addendum to 
include a description of Colorado Parks and Wildlife's previous 
consideration of reintroducing wolverines to Colorado as a nonessential 
experimental population (see 78 FR 7890, February 4, 2013). We also 
describe how this proposal was subsequently withdrawn in 2014 (see 79 
FR 47522, August 13, 2014), when we withdrew the February 4, 2013, 
proposed listing rule (78 FR 7864), and that there is currently no 
formal proposal to reintroduce wolverines to Colorado.
    (PR8) Comment: Two peer reviewers provided additional documentation 
regarding roads acting as a barrier to wolverine dispersal. Both 
provided different situations where at least one wolverine was seen 
crossing roadways, including a multiple-lane highway. One peer reviewer 
also mentioned regularly seeing wolverine tracks crossing roadways.
    Our Response: We updated the wolverine SSA report addendum to 
reflect these observations and modified the text to clarify that 
highways can limit female gene flow in some situations, but they are 
not complete barriers to wolverine movements.
    (PR9) Comment: One peer reviewer questioned how the artificial 
cutoff of the U.S.-Canada international border influenced the results 
of the 2009 effective population size analysis (Schwartz et al. 2009, 
entire).
    Our Response: The effective population size estimate was only for 
the U.S. portion of the Northern Rockies, and there were no samples 
taken from Canada. As we stated in the wolverine SSA report addendum, 
connectivity to larger source

[[Page 83738]]

populations can alleviate the adverse effects of small effective 
population sizes (Frankham et al. 2014, entire). We also added a 
paragraph to the wolverine SSA report addendum to explain that because 
effective population size estimates for wolverine are small, 
connectivity with populations in Canada to allow for migration and gene 
flow is crucial to maintaining genetic diversity.
    (PR10) Comment: One peer reviewer was concerned that current data 
for the wolverine are not being compared to what is known historically. 
They specifically called out the comparison of population sizes, the 
distribution and abundance of wolverines in the contiguous United 
States, and the results of genetic studies.
    Our Response: As the peer reviewer mentioned, there is a lack of 
historical data to compare to current conditions. However, our 
assessment is a forward-looking one, based on current and future 
conditions, and not the change from historical conditions to current 
conditions.
    (PR11) Comment: One peer reviewer questioned the 40 percent decline 
in wolverine abundance within a national park complex in southwestern 
Canada (Mowat et al. 2020, entire; Barrueto et al. 2022, entire).
    Our Response: The Barrueto et al. (2022) effort is a decade-long 
research project that was peer reviewed and published in a scientific 
journal. We note that the initial population estimate was approximately 
50 wolverines at the start of the study, so a 40 percent decline over 
10 years results in the loss of approximately 15-20 wolverines. The 
wolverine SSA report addendum has been updated to provide this 
additional detail.
    (PR12) Comment: A peer reviewer suggested including additional 
detail on how species-specific trapping and snaring reduce the 
likelihood of incidentally capturing a wolverine.
    Our Response: We updated the wolverine SSA report addendum to 
include how trappers use pan tension, site selection, and snare height 
to reduce the likelihood of incidental capture. We also included 
additional information we received from the States on their efforts to 
reduce incidental trapping of wolverines.
    (PR13) Comment: One peer reviewer suggested that the median and 
quartiles presented in our modeling may not accurately capture the 
variability in environmental conditions. The reviewer suggested that in 
addition to calculating the lower-quartile, median, and upper-quartile 
at each individual grid cell and timestep, we should also calculate the 
maximum and minimum bracketing response.
    Our Response: We did not conduct the additional suggested analysis. 
The additional analysis would require significant work and time, and we 
conclude our approach includes the majority of plausible future 
outcomes and incorporates the best available information to inform our 
listing determination.

I. Final Listing Determination

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) and wolverine SSA report addendum 
(Service 2023, entire). 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 feet (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, which includes 
weasel, 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). In 
North America, wolverines 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 was most likely the result of unregulated 
trapping and predator poisoning campaigns. Following regulation of 
trapping and restrictions on the use of poison, the wolverine 
population rebounded to some extent, and their distribution expanded to 
refill a portion of their previously extirpated range. In the 
contiguous United States, wolverines are known to reproduce in 
Washington, Idaho, Montana, and Wyoming (Service 2023, figure 3). 
Solitary individuals or lone dispersing individuals have been observed 
in other western States (Oregon, Colorado, Utah, and California), but 
there is no evidence of reproduction in the contiguous United States 
outside of the Northern Rocky Mountains in Idaho, Montana, and Wyoming 
and the Cascade Mountains of Washington.

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and the implementing 
regulations in title 50 of the Code of Federal Regulations set forth 
the procedures for determining whether a species is an endangered 
species or a threatened species, issuing protective regulations for 
threatened species, and designating critical habitat for endangered and 
threatened species. In 2019, jointly with the National Marine Fisheries 
Service, the Service issued a final rule that revised the regulations 
in 50 CFR part 424 regarding how we add, remove, and reclassify 
endangered and threatened species and the criteria for designating 
listed species' critical habitat (84 FR 45020; August 27, 2019). On the 
same day, the Service also issued final regulations that, for species 
listed as threatened species after September 26, 2019, eliminated the 
Service's general protective regulations automatically applying to 
threatened species the prohibitions that section 9 of the Act applies 
to endangered species (84 FR 44753; August 27, 2019).
    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

[[Page 83739]]

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 species' expected response 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 we 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 the 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 wolverine SSA report and SSA report addendum document the 
results of our comprehensive biological review of the best scientific 
and commercial data regarding the status of the North American 
wolverine, including an assessment of the potential threats to the 
subspecies occurring in the contiguous United States. The wolverine SSA 
report and SSA report addendum do not represent our decision on whether 
the North American wolverine should be listed as an endangered or 
threatened species under the Act. However, they do 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.
    To assess viability of the North American wolverine occurring in 
the contiguous United States, we used the three conservation biology 
principles of resiliency, redundancy, and representation (Shaffer and 
Stein 2000, pp. 306-310). Briefly, resiliency is the ability of the 
species to withstand environmental and demographic stochasticity (for 
example, wet or dry, warm or cold years); redundancy is the ability of 
the species to withstand catastrophic events (for example, droughts, 
large pollution events), and representation is the ability of the 
species to adapt to both near-term and long-term changes in its 
physical and biological environment (for example, climate conditions, 
pathogen). In general, species viability will increase with increases 
in resiliency, redundancy, and representation (Smith et al. 2018, p. 
306). Using these principles, we identified the subspecies' ecological 
requirements for survival and reproduction at the individual, 
population, and species levels, and described the beneficial and risk 
factors influencing the subspecies' viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated the individual subspecies' life-
history needs. The next stage involved an assessment of the historical 
and current condition of the subspecies' 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 subspecies' responses to positive and negative 
environmental and anthropogenic influences. Throughout all of these 
stages, we used the best available information to characterize 
viability as the ability of a species (which, under the Act, includes 
any subspecies of fish or wildlife or plants, and any DPS of any 
species of vertebrate fish or wildlife which interbreeds when mature) 
to sustain populations in the wild over time. We use this information 
to inform our regulatory decision.
    Later in this document, we present a summary of the key results and 
conclusions from the 2018 wolverine SSA report and 2023 wolverine SSA 
report addendum; the full SSA report and SSA report addendum can be 
found at Docket No. FWS-R6-ES-2023-0216 on https://www.regulations.gov 
and at https://ecos.fws.gov/ecp/species/5123.

Distinct Population Segment

    Pursuant to the Act, we must consider for listing any species, 
subspecies, or, for vertebrates, any DPS of these taxa, if there is 
sufficient information to indicate that such action may be warranted. 
To interpret and implement the DPS provision of the Act and 
Congressional guidance, the Service and the National Marine Fisheries 
Service published, on February 7, 1996, an interagency Policy Regarding 
the Recognition of Distinct Vertebrate Population Segments under the 
Act (DPS policy; 61 FR 4722, February 7, 1996). The DPS policy 
addresses the recognition of DPSs for potential listing actions. The 
DPS 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 Lists 
of Endangered and Threatened Wildlife and Plants (Lists), 
reclassification, and removal from the Lists. They are: (1) 
Discreteness of the

[[Page 83740]]

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.
    We have conducted several DPS analyses of wolverines in the 
contiguous United States since 2010 in response to new information and 
legal challenges. We first found that the population qualified as a DPS 
in our 2010 12-month finding (75 FR 78030; December 14, 2010) on a 
petition to list the population as a DPS. We reaffirmed and summarized 
this finding in our February 4, 2013, proposed listing rule (78 FR 
7864). In 2020, we reversed our previous finding, based on information 
at the time which suggested the population was not discrete from 
wolverine populations in Canada (85 FR 64618; October 13, 2020). Below, 
we provide our revised evaluation of discreteness and significance 
under the DPS policy of the segment of the North American wolverine 
occurring in the contiguous United States. Where necessary and 
appropriate below, we explain how new information has led us to 
different conclusions from previous DPS analyses. The analysis 
contained in this rulemaking supersedes and replaces any previous DPS 
analysis for the segment of the North American wolverine occurring in 
the contiguous United States. We determined that the contiguous U.S. 
population of the North American wolverine meets the discreteness 
criterion in our DPS policy; it is delimited by the international 
boundary with Canada, and there are differences between the United 
States and Canada regarding control of exploitation, conservation 
status, and regulatory mechanisms that are significant in light of 
section 4(a)(1)(D) of the Act. We then determined that the North 
American wolverine population occurring in the contiguous United States 
is significant because its loss would result in a significant gap in 
the range of the taxon.

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 find marked separation from other populations to support 
discreteness of the contiguous U.S. wolverine population. We also did 
not find marked separation to support discreteness in our October 13, 
2020, withdrawal (85 FR 64618). Our review of the new information 
presented in the 2023 wolverine SSA report addendum has not altered 
that conclusion; we continue to find 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 
or morphologically discontinuous from wolverines in Canada based on 
genetic information that supports that Canadian wolverines repopulated 
the contiguous United States over the past several decades and there 
are no unique haplotypes in the contiguous U.S. population (McKelvey et 
al. 2014, entire; Pilgrim and Schwartz 2018, entire; Sawaya et al. 
2023, entire). Therefore, wolverines in the contiguous United States 
are not discrete based on marked separation from other populations of 
the same taxon.
    We next evaluate whether the wolverine population in the contiguous 
United States is discrete based on the international boundary with 
Canada. We separately consider below whether there is discreteness 
based on differences between the two countries in terms of control of 
exploitation, management of habitat, conservation status, or regulatory 
mechanisms that are 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 Control 
of Exploitation
    In our 2010 12-month finding (75 FR 78030; December 14, 2010) and 
2013 proposed listing rule (78 FR 7864; February 4, 2013), we noted 
that differences in control of exploitation exist between the United 
States and Canada, but concluded those differences did not result in 
discreteness because the differences favored the contiguous U.S. 
population, the population that is at risk. In the wolverine 2018 SSA 
report, we noted that trapping or hunting of wolverines is currently 
prohibited in the contiguous United States and is allowed in Canada 
(Service 2018, pp. 68-69). In that 2018 SSA report, we included an 
analysis of trapping efforts in southern Canada and trapping effort 
along the U.S.-Canada border, and based on that analysis, we found 
trapping to be limited. We again concluded in our October 13, 2020, 
withdrawal document (85 FR 64618) that the differences in exploitation 
were not significant in light of section 4(a)(1)(D) of the Act 
(inadequacy of existing regulatory mechanisms).
    However, new information available since the publication of the 
October 13, 2020, withdrawal document indicates that trapping in Canada 
was likely causing more of an impact than previously thought. Recent 
studies show that harvest levels in portions of southeastern British 
Columbia and southwestern Alberta were unsustainable and causing 
population declines (Mowat et al. 2020, entire; Barrueto et al. 2022, 
entire). The areas evaluated are close enough to the international 
border that dispersing individuals would be likely to provide important 
genetic diversity and demographic rescue to the population in the 
contiguous United States. Harvest levels in Canada could negatively 
impact movement of individuals from Canada because, with reduced 
populations in Canada, there is less pressure on individuals to move 
south to areas in the United States to find suitable vacant home ranges 
(Sawaya

[[Page 83741]]

2023, pers. comm.). Furthermore, female wolverines appear less likely 
to disperse long distances or across major roadways compared to males 
(Sawaya et al. 2019, pp. 621-23). According to the latest genetic 
analyses, virtually all of the recent movement of wolverines from 
Canada to the United States appears to be by males (Sawaya et al. 2023, 
pp. 12-14, 17). Although there is now a trapping moratorium in 
southeastern British Columbia (British Columbia 2022, p. 76), it is 
unclear how long the moratorium will be in place or what the legacy 
effects of recent overharvest in southern British Columbia will be. In 
addition, trapping continues to be allowed in portions of southern 
Alberta. We conclude that harvest in Canada will continue to be an 
impediment to effective dispersal of wolverines into the United States. 
This, in turn, is likely to impact future genetic integrity of the 
population in the contiguous United States and limit the ability for 
demographic rescue should wolverines decline in number within the 
contiguous United States. Thus, we now conclude, based on new 
information, that the differences between Canada and the United States 
in control of exploitation are significant in light of section 
4(a)(1)(D) of the Act. Existing regulations in Canada have been 
inadequate to address this exploitation. Alberta continues to allow 
trapping in areas important for potential dispersing wolverines, and 
there is uncertainty on the length and effectiveness of the trapping 
moratorium in British Columbia and the long-term population effects of 
the recent overharvest there. As a result, we conclude the wolverine 
population in the contiguous United States meets the standard of 
``discreteness'' and we use the international border between the United 
States and Canada to define the northern boundary of the contiguous 
U.S. wolverine discrete population.
Discreteness Based on the International Border--Differences in 
Management of Habitat
    In the 2013 proposed listing rule (78 FR 7864; February 4, 2013) 
and October 13, 2020, withdrawal document (85 FR 64618), we stated that 
management activities (e.g., timber harvest, wildland firefighting, 
prescribed fire, and silviculture) can modify wolverine habitat, but 
this species appears to be little affected by changes to the vegetative 
characteristics of its habitat. However, recent research in Canada 
indicates that wolverines and other carnivores can be displaced from 
habitat that is subject to human disturbance that includes harvest cut-
blocks in forested habitat (Frey et al. 2020, entire). That said, most 
wolverine habitat in the contiguous United States occurs at high 
elevations in rugged terrain that is not usually conducive to intensive 
forms of silviculture and timber harvest. Although recent information 
indicates wolverines may be affected by disturbance from some types of 
habitat management, these disturbances occur in both the contiguous 
United States and southern Canada, where forested alpine habitats are 
managed in relatively similar ways and are relatively limited in scope 
and scale in wolverine habitat. Therefore, there are no significant 
differences in management of habitat between the United States and 
Canada pursuant to 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 
summarized 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 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 contiguous 
U.S. range appear to be at numbers so low that their continued 
existence could be at risk, especially in light of the threats to the 
subspecies. In the 2010 12-month 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 patches separated by unsuitable habitat. As a result, we 
concluded that the contiguous U.S. population of the wolverine met the 
discreteness criterion in our DPS policy. Consequently, we used the 
international border between the United States and Canada to define the 
northern boundary of the contiguous U.S. DPS of the North American 
wolverine in our December 14, 2010, 12-month finding (75 FR 78030) and 
our February 4, 2013, proposed listing rule (78 FR 7864).
    In our October 13, 2020, withdrawal document (85 FR 64618), based 
on new information at the time, we concluded there were not significant 
differences in control of exploitation, conservation status, and 
management of habitat, nor other threats to the wolverine requiring 
regulatory mechanisms to address them, and we concluded that there are 
no differences in regulatory mechanisms between the United States and 
Canada that are significant in light of section 4(a)(1)(D) of the Act. 
As a result, we concluded that the contiguous U.S. population of the 
North American wolverine did not meet the discreteness criterion in our 
DPS policy. Below, we revisit discreteness based on the international 
border and differences in conservation status considering new 
information presented in the wolverine SSA report addendum.
    Small Total Population Size--Wolverine population densities vary 
across North America and have been described as naturally low (van Zyll 
de Jong 1975, p. 434) given the species' large home range, wide-ranging 
movements, and solitary characteristics (Service 2018, p. 56). There 
are far fewer wolverines in the contiguous United States (around 300) 
than there are in Canada (more than 15,000) and Alaska (likely in the 
thousands) (Committee on the Status of Endangered Wildlife in Canada 
(COSEWIC) 2014, pp. 36, 47; Inman et al. 2013, p. 282; Service 2018, p. 
71), but this is largely 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. 
Even if wolverines occupied all available habitat in the contiguous 
United States, their populations would still be relatively small 
compared to Canada (i.e., the population capacity estimate was 644 (95% 
confidence interval (CI) = 506-1881) (Inman et al. 2013, p. 282). A 
small population in the contiguous United States would be less of a 
conservation concern if there were greater connectivity with the larger 
populations in Canada.
    Recent genetic information indicates wolverines from Canada have 
slowly repopulated the contiguous United States over the past century 
since the era of unregulated predator removal (Service 2018, pp. 45-50; 
Sawaya 2023, pers. comm.). We stated in the December 14, 2010, 12-month 
finding (75 FR 78030) that differences in population sizes between the 
contiguous United States and Canada were reflective of a difference in 
conservation status. In our October 13, 2020, withdrawal document (85 
FR 64618), based on new information, we concluded that the contiguous 
U.S. wolverines represent a peripheral

[[Page 83742]]

population at the southern extent of the North American wolverine's 
range. Thus, we considered the small population size of wolverines in 
the United States to be a natural result of the limited habitat 
available and not reflective of a difference in conservation status. 
Our 2020 determination on this point was made with the understanding 
that there was sufficient connectivity with Canada such that dispersing 
wolverines could bolster the small population in the contiguous United 
States. However, new information on wolverine dispersal and genetic 
connectivity indicates that wolverines appear to be impacted by recent 
overharvest in Canada, barriers to female wolverine dispersal, and 
development in dispersal corridors between suitable habitat (Barrueto 
et al. 2022, p. 4; Sawaya et al. 2023, pp. 12-14; Balkenhol et al. 
2020, p. 799). Because of this, the small population in the contiguous 
United States is more at risk from future threats impacting population 
resiliency. We now conclude that the difference in population size on 
the contiguous U.S. side of the international border is 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--In our December 14, 2010, 12-month 
finding (75 FR 78030) and February 4, 2013, proposed listing rule (78 
FR 7864), in support of our conclusion that differences in conservation 
status between the United States and Canada exist that are significant 
in light of section 4(a)(1)(D) of the Act, we discussed the difference 
in wolverine effective population size between the contiguous United 
States and Canada. The 2013 proposed listing 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 provided in 
our SSA report (Service 2018, pp. 46-47), effective population sizes 
(Ne) are typically smaller than census population sizes. 
Ne is the number of individuals in a population that would 
result in the same loss of genetic diversity, inbreeding, and genetic 
drift, if they behaved in the manner of an idealized population (equal 
sex ratio, random mating, all adults producing offspring, equal numbers 
of offspring per parent, and a constant number of breeding individuals 
across generations) (Frankham 1995, p. 96). The concept of effective 
population size relates to population viability because, as a general 
rule, closed populations with random mating that have effective 
population sizes (1) below 50 are at higher risk of inbreeding 
depression, and (2) below 500 are more likely to lose genetic variation 
important to maintaining long-term evolutionary potential. In addition, 
small, isolated populations are more vulnerable to extinction through 
interactions between environmental, genetic, and demographic factors 
(Caughley 1994, pp. 221-227). Importantly, the concept and guidelines 
for genetically effective population size were developed for a single, 
isolated population (Laikre et al. 2016, p. 280). Fragmentation can 
further exacerbate inbreeding depression and genetic loss, while 
connectivity to larger source populations can alleviate the adverse 
effects of small effective population sizes (Frankham et al. 2014, p. 
60).
    In our October 13, 2020, withdrawal document (85 FR 64618), we 
acknowledged the low effective population size of wolverines in the 
contiguous United States but found this was not a concern given the 
evidence of genetic connectivity between the United States and Canada. 
We stated the currently known spatial distribution of genetic 
variability in wolverines in North America appeared 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) 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. We stated 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 concluded that this 
level of migration from the north had already been occurring following 
the end of intense predator removal campaigns that affected this 
subspecies. Given observations of wolverines moving vast distances over 
varied terrain and across the U.S.-Canada border, our 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 U.S. wolverines, we believed that wolverines in the 
contiguous United States were not separated genetically from the larger 
population in Canada. In our October 13, 2020, withdrawal document (85 
FR 64618), we concluded that wolverines in the contiguous United States 
exhibit genetic and phenotypic similarities with wolverines in Canada 
that implied connectivity with Canada. As such, we concluded in that 
withdrawal document that it was not biologically appropriate to 
consider the low effective population size of wolverines on the 
contiguous U.S. 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.
    In our 2023 wolverine SSA report addendum, we summarized our 
evaluation of the available information related to the effective 
population size of wolverines in the contiguous United States, recent 
trapping/harvest in Canada, and genetic connectivity of wolverines 
between the United States and Canada. We are not aware of any new 
estimates of effective population size for wolverines in the contiguous 
United States; therefore, the Ne estimate of the wolverine 
population in the Northern Rocky Mountains (35) provided by Schwartz et 
al. (2009) represents the best available scientific information 
regarding effective population sizes in the U.S. portion of the 
Northern Rocky Mountains (Service 2023, p. 27). In the 2023 wolverine 
SSA report addendum, we estimated the effective population size of the 
wolverine population in the North Cascade Mountains, resulting in an 
estimate of Ne = 4 (Service 2023, p. 27). When viewed in 
isolation, the overall effective population sizes for wolverines in the 
contiguous United States are under the conservation thresholds for 
short- and long-term genetic health (50 and 500, respectively). New 
information suggests recent trapping harvest in southwestern Canada 
resulted in population declines in some areas that may be important 
sources of dispersing individuals to the contiguous United States 
(Service 2023, pp. 41-42). Furthermore, new information shows that 
female wolverine movement is influenced by major transportation 
corridors and that the Trans-Canada Highway could be an impediment to 
female movement (Service 2023, p. 28). Overall, the effective 
population size estimates of wolverines in the contiguous United States 
are small

[[Page 83743]]

compared to conservation rules-of-thumb and presumably smaller than the 
effective population size of wolverines in Canada. Only one or two 
migrants per generation are likely needed to achieve genetic population 
connectivity (Cegelski et al. 2006, p. 13); however, based on new 
information on gene flow and dispersal, we cannot assume this level of 
immigration from Canada is occurring. The contiguous U.S. population 
may be at risk of impacts from low effective population size without 
sufficient gene flow with Canada. We now conclude that the difference 
in effective population size on the U.S. side of the international 
border results in a significant difference in conservation status in 
light of section 4(a)(1)(D) of the Act as it applies to discreteness.
    Habitat Fragmentation--In our December 14, 2010, 12-month finding 
(75 FR 78030) and February 4, 2013, proposed listing rule (78 FR 7864), 
we stated that wolverine habitat in the contiguous United States 
consists of small, isolated areas 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 connectivity between subpopulations, and this also 
makes them more vulnerable to external threats (75 FR 78030; December 
14, 2010). This was used to support our justification for discreteness.
    The breeding range of wolverines in the contiguous United States 
largely exists in high-elevation alpine forested habitats. Those alpine 
areas with established wolverine home ranges are separated by expanses 
of lower elevation valley habitats that are not conducive to wolverine 
home range establishment but do provide varying levels of connectivity 
between home ranges or subpopulations. In Canada and Alaska, habitats 
are more contiguous and much less fragmented than wolverine habitat in 
the contiguous United States. The fragmented nature and distribution of 
wolverine habitat in the contiguous United States puts wolverines 
occurring in the contiguous United States at higher risk of impacts 
from climate change and other stressors compared to wolverines 
occurring in Canada and Alaska. We conclude that the difference in 
habitat fragmentation on the contiguous U.S. side of the international 
border results in a significant 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
    Wolverines are currently protected under various State regulatory 
designations in the States where the species occurs in the western 
United States (Service 2023, table 10). In Canada, provincial 
designations for the wolverine include endangered in Labrador, and 
threatened in Ontario and Qu[eacute]bec (``threatened'' is equivalent 
to endangered in Qu[eacute]bec), with the remaining provincial 
designations ranging from no ranking to sensitive or special concern to 
the Vancouver Island population's designation as imperiled (COSEWIC 
2014, p. 44).
    Current regulatory mechanisms prohibit trapping or harvest of 
wolverines in the contiguous United States, while trapping is legal in 
Canada and occurs in parts of the range that could be a source of 
important dispersers to the contiguous United States. We acknowledge 
that there is currently a trapping moratorium in a portion of British 
Columbia resulting from studies showing population declines in that 
area related to trapping (Service 2023, pp. 44-45). However, that 
moratorium is temporary and only covers a portion of the Canadian range 
(e.g., it does not include Alberta). As discussed above, there are 
significant differences in control of exploitation that may be impeding 
movement of wolverines, from Canada to the contiguous United States. We 
conclude that there are differences in regulatory mechanisms related to 
control of exploitation between the United States and Canada that are 
significant in light of section 4(a)(1)(D) of the Act.
Discreteness Conclusion
    Based on our updated analysis described above and supported by 
information in the wolverine SSA report and the wolverine SSA report 
addendum, the contiguous U.S. population of the North American 
wolverine meets the discreteness criterion in our DPS policy (61 FR 
4722; February 7, 1996). It is delimited by the international boundary 
with Canada, given differences in control of exploitation, conservation 
status, and regulatory mechanisms that are significant in light of 
section 4(a)(1)(D) of the Act. After determining that a vertebrate 
population is discrete, we are required to complete an analysis to 
determine if the population in question is significant according to our 
DPS policy; that analysis follows.

Analysis of Significance

    If we determine a population segment is discrete, its biological 
and ecological significance will then be considered in light of 
Congressional guidance that the authority to list DPSs be used 
sparingly while encouraging the conservation of genetic diversity. In 
carrying out this examination, we consider available scientific 
evidence of the population's importance to the taxon to which it 
belongs (i.e., the North American wolverine). Our DPS policy states 
that this consideration may include, but is not limited to: (1) 
persistence of the discrete population segment in an ecological setting 
unusual or unique for the taxon; (2) evidence that loss of the discrete 
population segment would result in a significant gap in the range of 
the taxon; (3) evidence that the discrete population segment represents 
the only surviving natural occurrence of a taxon that may be more 
abundant elsewhere as an introduced population outside its historical 
range; or (4) evidence that the discrete population segment differs 
markedly from other populations of the species in its genetic 
characteristics. Below, we address considerations 1, 2, and 4. 
Consideration 3 does not apply to the continental U.S. wolverine 
population because North American wolverines are distributed widely 
across Alaska and Canada.
    In our December 14, 2010, 12-month finding (75 FR 78030), we 
conducted an exhaustive analysis of the significance of the contiguous 
U.S. population of the North American wolverine; this analysis was 
incorporated by reference into our February 4, 2013, proposed listing 
rule (78 FR 7864). In the analysis, we concluded that the wolverine 
population in the contiguous United States is significant because its 
loss would result in a significant gap in the range of the taxon. In 
our October 13, 2020, withdrawal document (85 FR 64618), we did not 
present an assessment of significance under the DPS policy because, at 
that time, we determined that the wolverine population in the 
contiguous United States was not discrete, and thus there was no need 
to assess significance. Because we have now determined the wolverine 
population in the contiguous United States is discrete, we reviewed and 
present an update to our 2010 and 2013 assessment of the significance 
of the wolverine population occurring in the contiguous United States 
using the best available information.

[[Page 83744]]

Unusual or Unique Ecological Setting
    Wolverines occupy a variety of habitats within North America, 
including Arctic tundra, subarctic-alpine tundra, boreal forest, mixed 
forest, redwood forest, and coniferous forest (Banci 1994, p. 114). 
Wolverines in the contiguous United States exist in an ecosystem that 
includes high-elevation, remote, rugged, alpine forested terrain and 
non-forested habitats around the tree line that retain snowpack into 
the spring. The ecoregions inhabited by wolverines in the contiguous 
United States are also present in large portions of their occupied 
range in Canada and Alaska (Service 2018, appendix A).
    Wolverines in the contiguous United States appear to use habitat 
attributes that are similar to wolverine populations in Canada and 
Alaska, where wolverines also use alpine habitats, and do not appear to 
exist in an unusual or unique ecological setting. Thus, we again do not 
rely on this factor when determining that the wolverine in the 
contiguous United States is significant to the taxon as a whole.
Significant Gap in the Range of the Taxon
    Wolverines once lived throughout the North American Rocky Mountains 
from Alaska and Canada, south through Colorado and into New Mexico, and 
in the North Cascades of Washington and the Sierra Nevada Range of 
California. During the late 1800s and early 1900s, the wolverine 
population declined or was extirpated in much of the contiguous United 
States (Service 2018, p. 1). Wolverines have since recolonized parts of 
the contiguous United States, and the current breeding range includes 
the Southern Rocky Mountains of Idaho, Montana, and Wyoming and the 
Cascades of Washington (Service 2023, figure 3). Individual wolverines 
have been documented in California, Colorado, Oregon, and Utah; 
however, breeding populations are not known to exist in these areas. 
The contiguous United States represents the southernmost extent of the 
wolverine's range in North America.
    Our significance determination in the December 14, 2010, 12-month 
finding (75 FR 78030) concluded that the loss of wolverines in the 
contiguous United States would result in a significant gap in the range 
of the taxon. This determination was based on an estimate of the 
historical range (not current range) of wolverine in the contiguous 
United States. This relied on a latitudinally-based interpretation of 
historical range in the contiguous United States, the majority of which 
was unoccupied at the time the estimation was made and remains 
unoccupied by wolverines. We stated in 2010 that the loss of the 
population in the contiguous United States would be significant because 
it would substantially curtail the range of the wolverine by moving the 
southern range terminus approximately 15 degrees latitude to the north 
(or approximately 40 percent of the presumed latitudinal extent of the 
wolverine's range in North America). For reference, the U.S. border 
with Canada is 49 degrees North latitude. Fifteen degrees south of the 
border (at 34 degrees North latitude), the assumed 15-degree gap in 
latitude (49 degrees North minus 34 degrees North) presented in the DPS 
analysis in the December 14, 2010, 12-month finding (75 FR 78030), 
lands on 34 degrees North latitude, which runs through western States, 
including southern California and approximately the middle of Arizona 
and New Mexico, significantly south of the currently occupied range of 
wolverine in United States.
    During the development of our 2018 wolverine SSA report and 2023 
SSA report addendum, we conducted an extensive analysis of the recent 
and historical occurrence records for wolverines in the contiguous 
United States (Service 2018, pp. 12-16; Service 2023, pp. 3-14). Our 
updated significance analysis is based on an updated, spatially 
explicit assessment of the current range of wolverines in the 
contiguous United States. We used the current range (Service 2023, 
figure 2) to provide a more accurate reflection of the range currently 
being used by populations of wolverines in the contiguous United States 
supported by the best available information. By focusing on the current 
range, and not the historical range, we avoid including large sections 
of the western United States that do not have high-quality wolverine 
habitat (southern California and northern Arizona and New Mexico) in 
our significance analysis, and thus we are able to better assess the 
significance of the population in the contiguous United States relative 
to the larger taxon. The current range of wolverines in the contiguous 
United States covers approximately 58,998,140 acres (238,757 km\2\) of 
high-quality wolverine habitat with recent wolverine occurrences (from 
2009-2023) (Service 2023, figure 2), the loss of which would move the 
southern range terminus approximately 12 degrees latitude to the north.
    Furthermore, the southernmost portion of the range may be important 
for conservation, as it may allow for unique adaptive potential in the 
face of a changing global climate and future reduction in cold and 
snowy conditions. Populations on the periphery of species' ranges tend 
to be given lower conservation priority because they are thought to 
exist in low-quality habitats and are also thought to be the 
populations that are least likely to survive a reduction in range (Wolf 
et al. 1996, p. 1147). However, this tendency presumes that the 
ultimate cause of the species' extinction will be one that operates by 
eroding away the species' range beginning at the periphery and 
progressing to the center. This presumption is based on biogeographical 
information that habitat and population densities of species are 
highest near the center of the species' range and decline near the edge 
(Brown and Lomolino 1998, figure 4.16). Data from documented range 
collapses of species from around the world, however, illustrate that 
species' ranges tend to collapse to peripheral areas rather than to the 
center of their historical ranges (Lomolino and Channell 1995, p. 342; 
Channell and Lomolino 2000, pp. 84-86). Of 96 species whose last 
remnant populations were found either in the core or periphery of their 
historic ranges (rather than some in both core and periphery), 91 (95 
percent) of the species were found to exist only in the periphery, and 
5 (5 percent) existed solely in the center (Channell and Lomolino 2000, 
p. 85). Available scientific data support the importance of peripheral 
populations for conservation (Fraser 1999, entire; Lesica and Allendorf 
1995, entire).
    Based upon the loss of approximately 58,998,140 acres (238,757 
km\2\) of high-quality wolverine habitat from the southern extent of 
the range and the adaptive potential that part of the range may provide 
against oncoming climate change impacts, and a 12 degree latitudinal 
gap in the North American wolverine's range that would result if the 
U.S. population was lost, we determine that the loss of the contiguous 
U.S. wolverine population would result in a significant gap in the 
range of the taxon. Thus, the DPS meets the definition of significant 
in our DPS policy.
Marked Genetic Differences
    In the contiguous United States, small, isolated wolverine 
populations are likely dependent on gene flow from Canada for 
population persistence (Cegelski et al. 2006, pp. 208-209; McKelvey et 
al. 2014, entire). In the Northern Rocky Mountains, the best available 
genetic data indicate genetic

[[Page 83745]]

structuring of populations despite some dispersal (Cegelski et al. 
2006, pp. 204-205, 208; Sawaya et al. 2023, pp. 12-14). Genetic 
structuring reflects the amount of interbreeding between different 
groups of an organism where more structure indicates less interaction 
between groups, increased genetic isolation, increased potential for 
inbreeding, and lower genetic diversity. Given the relatively recent 
recolonization of wolverines in the contiguous United States from 
Canada (within the last 60-70 years), nuclear genetic diversity was 
lower in the southern periphery of the subspecies' range in the south 
(Sawaya et al. 2023, pp. 9-11). Nuclear DNA analyses indicated 
differences in allele frequencies between the United States and Canada 
along the Rocky Mountains, with some areas of overlap in wolverine 
populations straddling the border due to male-mediated gene flow. 
Females appear to be segregated near the international border due to 
their higher rates of philopatry (the tendency of an animal to remain 
in or return to the area of its birth) than males and their apparently 
greater tendencies to avoid crossing major roadways, including the 
Trans-Canada Highway (Highway 1) and the Crowsnest Highway (Highway 3) 
in southern British Columbia (Sawaya et al. 2023, pp. 12, 17). Both 
highways were opened in the 1960s (British Columbia Ministry of 
Transportation and Highways 2001, pp. 16, 20). Since then, they have 
been widened in many areas, and traffic volumes have substantially 
increased (British Columbia Ministry of Transportation and Highways 
2001, pp. 7-11, 16-21). Mitochondrial DNA patterns in the Rocky 
Mountains showed no unique contemporary maternal lineages detected 
south of the international border, which is consistent with 
observational data indicating that wolverines recolonized the 
contiguous United States from Canada within the last 60-70 years 
(Sawaya et al. 2023, pp. 2, 16-17). Substantially lower mitochondrial 
DNA diversity in the United States, as compared to mitochondrial DNA 
diversity in Canada, is consistent with the nuclear DNA signals of 
limited contemporary female gene flow between the countries along the 
Northern Rocky Mountain range and the wolverine's relatively recent 
recolonization at the southern edge of their range (Sawaya et al. 2023, 
p. 17).
    In the North Cascades, global positioning system (GPS) tracking 
data show that wolverines in western Washington and southern British 
Columbia form a small transboundary population (Aubry et al. 2023, p. 
4). Preliminary results from a large population genetics study of this 
transboundary population show that wolverines in the North Cascades are 
genetically isolated from other wolverine populations in the United 
States and Canada and likely went through a genetic bottleneck with few 
founders (Sawaya 2023, pers. comm.). The population has low 
heterozygosity (less than 0.5) and could be experiencing some level of 
inbreeding (Sawaya 2023, pers. comm.). However, there are no 
indications or evidence that individuals or population dynamics are 
being adversely affected by inbreeding depression (Sawaya 2023, pers. 
comm.).
    As part of the multi-State wolverine occupancy surveys in 2016-
2017, researchers obtained 240 wolverine DNA samples (Lukas et al. 
2020, p. 846). These samples represented 26 unique females and 24 
unique males (Lukas et al. 2020, p. 846). Analyses of the mitochondrial 
DNA control region revealed regional structuring (i.e., regional 
grouping), with all of the samples in Idaho, Montana, and Wyoming 
assigned to Haplotype Wilson A (the most abundant haplotype in North 
America) and all of the samples in Washington assigned to Haplotype 
Wilson C (Lukas et al. 2020, p. 846). These results are consistent with 
the latest genetic analysis from the large transboundary study (Sawaya 
et al. 2023, entire) and previous mitochondrial DNA studies showing 
that the Northern Rocky Mountains and North Cascades do not appear to 
share any contemporary haplotypes (McKelvey et al. 2014, p. 328).
    The genetic differences between the contiguous United States and 
Canada consist of lower genetic diversity in the United States, a 
difference that is a reflection of the recent recolonization of 
wolverines into the contiguous United States from Canada over the last 
century. There are no unique haplotypes present in contiguous U.S. 
wolverines that are not already present in larger populations in Canada 
and Alaska. As we noted in our analysis in the December 14, 2010, 12-
month finding (75 FR 78030), this is not the kind of genetic difference 
that would lead us to conclude that a population is significant under 
our DPS policy. The DPS policy is designed to ensure the protection of 
important components of a species' evolutionary legacy rather than 
populations that simply have lower genetic diversity due to recent 
recolonization from a larger source population. Therefore, as in our 
2010 analysis, we do not find marked genetic differences as a basis for 
determining significance for this DPS.
Summary for Significance
    We evaluated whether the discrete population segment of wolverines 
in the contiguous United States is also significant, considering 
factors such as whether the population segment is in an ecological 
setting unusual or unique for the taxon; whether the loss of the 
discrete population segment would result in a significant gap in the 
range of a taxon; whether the discrete population segment represents 
the only surviving natural occurrence of a taxon that may be more 
abundant elsewhere as an introduced population outside its historical 
range; or whether the discrete population segment differs markedly from 
other populations of the species in its genetic characteristics. We 
conclude that the wolverine population in the contiguous United States 
is significant because its loss would result in a significant gap in 
the range of the taxon.

DPS Conclusion

    Based on the best available information, we conclude that the 
population of wolverines in the contiguous United States is discrete 
and significant in relation to the remainder of the subspecies in North 
America. As a result, the population of wolverines in the contiguous 
United States is 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. We have determined 
that wolverines in the contiguous United States qualify as a DPS and, 
therefore, are a listable entity. Below, we provide a status 
determination of the wolverine DPS in the contiguous United States.

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of the DPS 
and its resources, and the threats that influence the DPS's current and 
future condition, in order to assess the DPS's overall viability and 
the risks to that viability.
    In preparing the 2018 wolverine SSA report and the 2023 SSA report 
addendum, we reviewed available reports and peer-reviewed literature, 
incorporated survey information, and

[[Page 83746]]

contacted species experts to collect additional unpublished information 
for the North American subspecies (Gulo gulo luscus). We identified 
uncertainties and data gaps in our assessment of the current and future 
status of the subspecies. We also evaluated the appropriate analytical 
tools to address these gaps, consulted with species experts, prepared 
updated maps of the known subspecies' distribution and breeding range 
in the contiguous United States, and evaluated new models of spring 
snow. In some instances, we used publications and other reports 
(primarily from Fenno-Scandinavia) of the Eurasian subspecies (G. g. 
gulo) as a surrogate in completing our status assessment.
    Since the publication of the October 13, 2020, withdrawal document 
(85 FR 64618), more than 180 new publications have been issued (see 
list of citations in the 2023 wolverine SSA report addendum). This is a 
substantial amount of new information for a difficult-to-study animal 
like the wolverine and has added significantly to our understanding of 
wolverine biology. This new information has also highlighted new 
insights into the subspecies' biological needs, threats, and the 
wolverine's interactions with abiotic and biotic habitat features.
    We also conducted an updated geospatial analysis to map verified 
wolverine occurrences and approximate breeding ranges in the contiguous 
United States. This was informed by recent multi-State monitoring data 
(Lukas et al. 2020, entire; Mosby et al. 2023, entire).
    Our updated analyses, since the publication of the October 13, 
2020, withdrawal document, of the current and predicted future 
condition for the wolverine is presented in the wolverine SSA report 
addendum and summarized here. Our future-condition analysis includes 
the potential conditions that the subspecies or its habitat may face in 
the future. This includes consideration of threats most likely to 
impact the subspecies at the population or rangewide scales in the 
future, including potential cumulative impacts. The spatial expansion 
to our climate analysis is a major improvement from the snow 
projections used in our 2018 SSA report, which focused only on Rocky 
Mountain National Park (Colorado) and Glacier National Park (Montana). 
We now focus on five modeling domains that overlap with occupied and 
potential wolverine habitat in the contiguous United States across 
latitudinal, longitudinal, and elevation gradients. These include: (1) 
Cascades (Washington); (2) Northern Rocky West (Washington, Idaho, and 
Montana); (3) Northern Rocky (Idaho and Montana); (4) Mid-Rocky (Idaho, 
Montana, and Wyoming); and (5) Southern Rocky (Colorado and New Mexico) 
(Service 2023, p. 49). In our updated climate assessment, we use a 
timeframe out to end of century for assessing future effects to North 
American wolverine viability from climate change and other threats. 
Beyond 2100, climate modeling uncertainty increases substantially. Our 
previous assessment considered in the October 13, 2020, withdrawal 
document (85 FR 64618) looked at a timeframe 50 years into the future. 
We conclude that end of century is a reasonable timeframe, 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 
subspecies needs to maintain viability by characterizing the status of 
the subspecies in terms of resiliency, redundancy, and representation 
(Wolf et al. 2015, entire). Resiliency is having sufficiently large 
populations for the subspecies 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 
subspecies 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 subspecies. The 
greater the number of populations a subspecies has distributed over a 
larger landscape, the better it can withstand catastrophic events.
    Representation is having the breadth of genetic makeup of the 
subspecies 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 
subspecies' range. The more representation, or diversity, a subspecies 
has, the more it is capable of adapting to changes (natural or human-
caused) in its environment. In the absence of subspecies-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

    Wolverine populations are characterized by naturally low densities. 
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 and activities. 
The wolverine is a snow-adapted, cold-climate animal in its physiology 
and morphology (Telfer and Kelsall 1984, p. 1830); phylogeography 
(historical processes that may be responsible for past and present 
geographic distributions of genealogical lineages); and behavior and 
habits (Fisher et al. 2022, p. 7).
    Wolverines consume a variety of food resources, and seasonal 
switching of prey is commonly observed. Unlike wolverine populations in 
Eurasia, wolverines in the contiguous United States rarely prey on 
livestock. During our extensive literature review in preparing the 2023 
wolverine SSA report addendum, we discovered only two instances of 
wolverine depredation in the United States since our 2018 SSA report; 
one wolverine that had depredated sheep in Utah, and another that was 
caught in a chicken coop in Washington (Service 2023, pp. 10, 38).
    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 (only observed in snow in the contiguous 
United States), and several additional months of maternal care (Service 
2018, p. 22). 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.
    In our 2018 wolverine SSA report, we defined the physical and 
ecological requirements of wolverine in the contiguous United States 
(see (1), (2), and (3), below). In light of new information regarding 
wolverine habitat associations that provides support for the 
wolverine's strong preference for areas with cold and snowy conditions, 
we have added a fourth ecological requirement (see (4), below). The 
requirements are:
    (1) Large territories in relatively inaccessible landscapes, at 
high elevation (1,800 to 3,500 m (5,906 to 11,483 ft));

[[Page 83747]]

    (2) Access to a variety of food resources that vary with seasons;
    (3) Physical/structural features (e.g., talus slopes, rugged 
terrain) linked to reproductive behavioral patterns; and
    (4) Habitats characterized by the presence of persistent spring 
snow (of greater than or equal to 1 meter on May 1) for survival and 
reproduction.
    Our 2023 wolverine SSA report addendum affirms these requirements 
and the species characterization in our 2018 SSA report.
Habitat
    Research published since our 2018 wolverine SSA report confirms 
that broad-level habitat selection (subspecies' range, individual home 
range) at the southern edge of the wolverine's distribution can be 
accurately predicted using a small number of high-elevation variables 
and terrain features (Carroll et al. 2021a, pp. 1470-1471; Aubry et al. 
2023, p. 7). New evidence from around the world reinforces that snow--
especially persistent spring snow--is an important predictor of broad-
scale wolverine distribution and density (Aubry et al. 2023, pp. 15-16; 
Carroll et al. 2020, p. 8; Fisher et al. 2022, p. 10; Glass et al. 
2021, entire; Mowat et al. 2020, p. 220). Within home ranges, the 
precise nature of the relationship between wolverine space-use and snow 
is complex, involving multiple snow characteristics (e.g., density, 
depth, and melt), various phases of the wolverine lifecycle (e.g., 
denning, feeding and food caching, within-territory movements, and 
dispersal) and sex-specific habitat selection (Carroll et al. 2021, p. 
1469; Glass et al. 2021, entire; Heinemeyer et al. 2019, p. 16). While 
wolverines appear capable of occupying and reproducing in areas without 
persistent spring snow in some ecological contexts, at a continent-wide 
scale, wolverine dens outside of areas with persistent spring snow have 
thus far only been documented to occur in colder boreal or arctic 
environments in Canada and Alaska (Aronsson and Persson 2017, p. 266; 
Copeland et al. 2010, pp. 240-242; Fisher et al. 2022, p. 8; Jokinen et 
al. 2019, pp. 6-8; Webb et al. 2016, pp. 1466-1467).
    In the Greater Yellowstone Ecosystem, distance to high-elevation 
talus, snow water equivalent (a surrogate for snow depth), and 
latitude-adjusted elevation were the most important environmental 
factors explaining selection of wolverine home ranges and habitats 
within home ranges (Service 2023, p. 16). These habitat variables are 
also known to be important in defining the wolverine's distribution 
(Inman et al. 2013, p. 278).
    Results from dispersal suitability models developed for wolverines 
indicate that isolation by landscape resistance (areas that individuals 
are less likely to traverse due to high energy, mortality, or other 
biological costs) explained more of the variation in wolverine genetic 
differences than did isolation by distance (Balkenhol et al. 2020, pp. 
795-797). This means that wolverines are moving non-randomly across the 
landscape in association with specific landscape features. Snow depth 
(average 1-year snow depth at 1-km\2\ resolution), terrain ruggedness 
(measure of how jagged or flat the terrain is on average), and housing 
density (census block housing density per 1 km\2\) best predicted gene 
flow in wolverines (Balkenhol et al. 2020, pp. 795-797). Snow depth was 
the most important variable for explaining variation in genetic 
differences overall (Balkenhol et al. 2020, p. 790). At broad spatial 
scales, housing density and terrain ruggedness were the most important 
factors, where wolverines avoided areas of high housing density and 
preferred areas of terrain ruggedness, which explains the variation in 
wolverine genetic differences (Balkenhol et al. 2020, p. 790).
    In the Cascade Range in southern British Columbia and Washington, 
three climatic variables (proximity to the transitional zone near the 
alpine tree line, number of frost-free days per year, and annual 
precipitation as snow) were correlated with wolverine location data 
(Aubry et al. 2023, p. 10). Wolverine distribution in the Cascades is 
constrained by climatic conditions; snowy, cold environments delimit 
the areas that are ``overwhelmingly associated with resident 
wolverines'' (Aubry et al. 2023, p. 16). The highest-use areas were on 
the eastern side of the Cascades, where alpine habitats had fewer 
frost-free days (Aubry et al. 2023, p. 15). This is consistent with 
other models, indicating that wolverines rely on the transitional zone 
between the tree line, below which environmental conditions become too 
warm, and upper elevations of permanent ice and snow, where there is 
insufficient food and cover to support basic life-history requirements 
for wolverines (Aubry et al. 2023, pp. 13-14).
    A study using GPS location data on 38 wolverines from 2001 to 2010 
analyzed wolverine home range habitat selection across the western 
United States by identifying landscape variables that were highly 
correlated with wolverine home ranges (Carroll et al. 2020, entire). 
The resource selection function model included landform (e.g., ridges 
and peaks), vegetation classification, distance to high-elevation 
talus, latitude-adjusted elevation, average monthly snow water 
equivalent, and human modification (Carroll et al. 2020, p. 8). Core 
areas were identified, and connectivity was assessed, between these 
core areas using a landscape resistance model, validated with GPS 
location data from dispersing wolverines (Service 2023, figure 3). 
Results showed that resident wolverines in core habitats are far more 
sensitive to low-quality habitat than are dispersing individuals, but 
that dispersers still follow lower-resistance pathways that connect 
higher quality core habitats (Carroll et al. 2020, p. 9). Another study 
modeled within-home range habitat selection by wolverines in areas of 
the Northern Rocky Mountains with high amounts of winter backcountry 
recreation and found significant differences in male and female habitat 
selection (Heinemeyer et al. 2019a, p. 9). The best model for male 
wolverines included distance to roads and proportion of lower elevation 
grass and shrub cover, while the best model for female wolverines 
included talus, persistent spring snow cover (defined in the cited 
studies as snow cover present between April 24 and May 15), and forest 
edge-to-area covariates (Heinemeyer et al. 2019a, p. 9). Best models 
for both sexes included covariates for topographic position index, 
quadratic form of slope, distance to forest edge, solar insulation, and 
percentage cover of forest, riparian, and montane open cover types. 
This study also showed that wolverines are negatively affected by 
winter recreation (see Disturbance Due to Winter Recreational Activity, 
below).
    Multiple recent studies in Canada have provided further evidence of 
the influence of snow cover and human development/disturbance on 
wolverine distribution. Wolverine density in and around a national park 
complex in the southern Canadian Rocky Mountains was three times higher 
within these national parks than outside them, increased with spring 
snow cover, and decreased with increasing night light intensity (a 
measure of human development) (Barrueto et al. 2022, p. 4). Along the 
Front Range of the Canadian Rocky Mountains, wolverines selected areas 
with natural land-cover and high snow cover and avoided anthropogenic 
features and heterospecific competitors (Heim et al. 2019, pp. 2499-
2502). In the Rocky Mountains of Alberta, wolverine occurrence in space 
and time was best explained by coyote (Canis latrans) occurrence and 
the density of linear

[[Page 83748]]

disturbance features (e.g., roads, pipelines, seismic lines, motorized 
and nonmotorized recreational trails), with both of these factors 
decreasing the likelihood of wolverine occurrence (Chow-Fraser et al. 
2022, pp. 4-5). In the southern Canadian Rockies, wolverine density was 
found to be positively correlated with the number of years of 
persistent spring snow cover and negatively correlated with road 
density (Clevenger 2019, p. 62; Mowat et al. 2020, pp. 218-219). Female 
densities in areas with more cumulative years of persistent spring snow 
were higher than male densities, which suggests there may be a 
preference for snowy areas when denning. An additional study, also in 
the Canadian Rockies, found that food availability and human 
disturbance were major drivers of wolverine distribution in winter 
(Kortello et al. 2019, p. 7). Persistent spring snow was an important 
factor in explaining the variation in female wolverine distribution in 
winter and overall wolverine distribution at coarse scales (Kortello et 
al. 2019, p. 8). The researchers concluded that their results ``do not 
reject the hypothesis that wolverine occurrence is constrained by an 
obligate association with persistent spring snow'' (Aubry et al. 2007, 
p. 2154; Copeland et al. 2010, p. 244), ``but do suggest the 
alternative explanation that the relationship between spring snow and 
wolverine distribution could be functionally related to the 
distribution of food, disturbance or mortality risk'' (Kortello et al. 
2019, p. 8). We agree with their assessment and acknowledge the precise 
causal mechanism(s) for the apparent association of wolverine 
distribution and persistent spring snow are not yet clear. There may be 
a number of factors acting in concert to drive the wolverine's 
preference for cold and snowy conditions, and we have attempted to 
account for this in our analysis presented in this rule.
    A habitat selection study of 21 adult, non-denning wolverines (11 
female, 10 male) fitted with GPS collars in the Alaskan Arctic found 
that wolverines generally selected more rugged areas closer to streams, 
rivers, and lakes (Glass et al. 2021, p. 893). This study also showed 
that snow characteristics are important to wolverines for reasons other 
than solely creating reproductive dens. Specifically, they found that 
non-denning wolverines select deeper, denser snow, but only when that 
snow is not undergoing melt (Glass et al. 2021, pp. 894-895). The 
wolverine's observed preference for denser snow might be a function of 
both ease of movement across the surface, as well as the ability of 
denser snow to maintain snow cavities and tunnels (Glass et al. 2021, 
p. 895).
    Denning Habitat--Denning habitat has been a focus for wolverine 
conservation because wolverines have naturally low reproductive rates. 
Impacts to denning habitat could have important consequences for 
demographic rates (Fisher et al. 2022, p. 8). There is growing evidence 
that wolverines rely on subnivean space (the environment between snow 
and terrain) for thermoregulation, to escape predation risk, and/or to 
cache food (van der Veen et al. 2020, pp. 8-10; Fisher et al. 2022, p. 
10). Although wolverines have been documented denning in areas without 
persistent spring snow (Fisher et al. 2022, p. 8; Persson et al. 2023, 
entire), this phenomenon appears to be associated with cold, high-
latitude boreal or arctic forests rather than the alpine habitats used 
by wolverines in the contiguous United States. In the contiguous United 
States, there is no evidence that wolverines have denned in areas 
without persistent spring snow.
    Den-shifting behavior represents a tradeoff between moving--and 
risking potential energy loss and harm to offspring--versus staying in 
the original den site and risking exposure to disturbance or changed 
conditions, such as melting snow, that might make the original den site 
unsuitable (Heeres 2020, p. 9). In a study in northern Sweden focusing 
on 18 adult female wolverines fitted with GPS collars over an 11-year 
period and occupying 271 den sites, Heeres (2020, p. 15) determined 
that a female used an average of 12 den sites during a single denning 
season (range: 4-28; median: 10). Additionally, female wolverines had a 
higher probability of shifting den sites in forested habitats, compared 
to alpine habitats, which is likely a result of earlier snow melt in 
forests that may make den sites uninhabitable early in the season 
(Heeres 2020, p. 20). Other factors related to den-shifting behavior 
included the level of denning experience of the female wolverine, which 
was quantified as the number of previous reproductive attempts by an 
individual (lower den-shift probability), temperature (higher den-shift 
probability in the warmer forested habitats; nonsignificant den-shift 
probability in alpine habitat), food resource availability (higher den-
shift probability, which could be related to accessing food or 
increased human presence), and cub age (more shifting as cubs mature 
and are able to move to food resources) (Heeres 2020, pp. 20-22).
    In certain ecological contexts, individual wolverines and 
reproductive dens can exist in areas without substantial spring 
snowpack (Persson et al. 2023, p. 10; Jokinen et al. 2019, pp. 4-9). 
For example, Jokinen et al. (2019, pp. 6, 10) observed seven of eight 
wolverine dens (three primary and five secondary dens) in hollows of 
uprooted trees and not in snow; however, the researchers acknowledged 
that sample sizes were small and limited their ability to draw robust 
conclusions. Jokinen et al. (2019, p. 12) speculated that wolverines, 
in the absence of spring snow in Alberta, were able to meet their 
physiological needs through locally available features such as the 
cavity created by partially uplifted root masses, the thermal 
properties of thick moss, and the caching opportunities provided by 
deep peat accumulations. Wolverines are resourceful and may be more 
flexible in their denning requirements than documented by studies in 
other landscapes (Persson et al. 2023, p. 10; Jokinen et al. 2019, p. 
12; Glass et al. 2021, entire); however, it is also apparent that 
boreal forest communities have a series of unique properties conducive 
to wolverine denning, including cold spring temperatures and dense peat 
layers that might aid in insulating the den (Jokinen et al. 2019, p. 
12).
    At present, it remains uncertain whether the alpine ecosystems in 
the contiguous United States contain environmental conditions that 
would allow wolverines to switch denning behavior or use smaller or 
shallower patches of snow in response to changes in future snow under a 
changing climate. Even if they were able to make this shift, snow may 
be important to wolverines for more than just denning.
    Food Caching--Wolverines are physiologically and behaviorally 
adapted to caching perishable food in snow, boulders, and peat bogs for 
short- or long-term storage (van der Veen et al. 2020, pp. 2-3). In 
Scandinavia, wolverines cached food all year from scavenging and 
predation events, with the locations of food caches widely distributed 
across their home ranges (van der Veen et al. 2020, pp. 6-8). When 
caching, wolverines selected steep and rugged terrain in unproductive 
habitat types (habitats with fewer plants and animals) or in forest, 
indicating a preference for less-exposed sites that can provide cold 
storage or protection against pilferage. The observed year-round 
investment in caching by wolverines suggests that food predictability 
is important for their

[[Page 83749]]

survival and reproductive success. Increasing temperatures caused by 
climate change may provide new challenges for wolverines in at least 
two ways: (1) by decreasing the shelf-life of cached food, and (2) by 
increasing competition from pilferers that benefit from a warmer 
climate (van der Veen et al. 2020, pp. 8-10).

Areas of Uncertainty for Wolverine Habitat Needs

    The precise causal mechanism(s) for the apparent association of 
wolverine distribution and persistent spring snow are not yet clear. 
Hypotheses for this association include the importance of snow to 
create dens (Copeland et al. 2010, entire), the advantages of snow for 
catching prey within a wolverine's metabolic limits (Young et al. 2012, 
pp. 224-226), competitive advantages over other scavengers and 
predators in snow-covered areas (Service 2018, p. 6), thermoregulation 
(Service 2018, pp. 7-8), food storage and refrigeration (Inman et al. 
2012, p. 640), or some combination of these factors. The interplay of 
temperature and persistence of spring snow and the point at which 
temperature becomes limiting is also unknown.
    There is presumably some limit in appropriate habitat availability 
at which wolverines will not cross certain habitats or traverse certain 
barriers, but that threshold is not known. Understanding this threshold 
for females is particularly important because they often disperse 
shorter distances than males and appear to be more affected by 
potential barriers to movement, such as large multi-lane highways 
(e.g., Sawaya et al. 2019, pp. 621-623).
    Recent studies from Canada and Alaska have shown that apex 
predators and sympatric mesocarnivores (small to mid-sized carnivores 
that occur in the same area) can influence wolverine space use (e.g., 
Heim et al. 2019, pp. 2499-2504; Frey et al. 2020, pp. 1133-1137; Bell 
2021, pp. 46-47; Klauder et al. 2021, p. 569; Chow-Fraser et al. 2022, 
p. 4). In addition, it is possible that competitors such as coyotes 
that thrive within human-dominated landscapes could potentially 
displace wolverines in areas with substantial anthropogenic disturbance 
(Chow-Fraser et al. 2022, pp. 4-5). However, the influence of apex 
predators and intraguild competition on wolverine distribution, 
abundance, and dispersal in the contiguous United States remains 
largely unstudied.

Threats

    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. 
Threats evaluated for the wolverine in the contiguous United States 
include climate change (Factors A and E), 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), 
and small population effects (Factor E). We found that habitat loss as 
a result of climate change is the primary threat to the wolverine's 
future viability in the contiguous United States. We expect climate 
change to exacerbate effects from multi-lane roads, backcountry winter 
recreation, and human development, all of which could then impact 
genetic diversity and small population dynamics. A summary of the 
threats affecting the North American 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) and the 2023 wolverine SSA report addendum 
(Service 2023, pp. 30-47).
    Climate Change: The wolverine's evolutionary and phylogeographic 
history suggest a species adapted to cold and snowy climate conditions 
(Fisher et al. 2022, p. 7; Service 2023, pp. 24-25). The wolverine is a 
snow-adapted, cold climate animal in its physiology, morphology (Telfer 
and Kelsall 1984, p. 1,830), behavior, and habits. Wolverines have been 
classified as a ``chionphile'' or those animals with adaptations for 
snow (e.g., increased surface area on feet, pelt characteristics) (see 
definitions in Pruitt 1959, p. 172; Cathcart 2014, p. 22). We find that 
impacts from climate change (increasing temperatures and decreasing 
snowpack) have the largest potential to influence the North American 
wolverine's population viability in the future.
    To inform our assessment of the North American wolverine's status 
in the contiguous United States, we updated our previous climate change 
analysis, the details of which are summarized in the wolverine SSA 
report addendum (Service 2023, pp. 47-59). The spatial expansion to our 
climate change analysis is a major improvement from the snow 
projections used in our 2018 SSA report, which focused only on Rocky 
Mountain National Park (Colorado) and Glacier National Park (Montana). 
We now focus on five modeling domains that overlap with occupied and 
potential wolverine habitat in the contiguous United States across 
latitudinal, longitudinal, and elevation gradients: (1) Cascades 
(Washington); (2) Northern Rocky West (Washington, Idaho, and Montana); 
(3) Northern Rocky (Idaho and Montana); (4) Mid-Rocky (Idaho, Montana, 
and Wyoming); and (5) Southern Rocky (Colorado and New Mexico) (Service 
2023, p. 49). Central Idaho was not modeled due to constraints of time 
and resources. In our updated climate assessment, we use a timeframe 
out to year 2100 for assessing future effects to the North American 
wolverine's viability from climate change and other threats. Beyond 
2100, climate modeling uncertainty increases substantially due to the 
inability to predict human behavior, policy changes, and, by extension, 
future greenhouse gas emissions. Our previous assessment in the October 
13, 2020, withdrawal document (85 FR 64618) looked at a timeframe of 38 
to 50 years into the future. We find that end of century is a 
reasonable timeframe to consider, as it includes the potential for 
observing these effects and the wolverine's responses over several 
generations of the wolverine.
    Two scenarios were chosen from the Intergovernmental Panel on 
Climate Change (IPCC) Sixth Assessment Report to bracket the 
uncertainty regarding future greenhouse gas emission scenarios (Tebaldi 
et al. 2021, p. 258). The two emission scenarios used in the analyses 
are referred to as SSP2-4.5 and SSP5-8.5; SSPs replace representative 
concentration pathways (RCPs) from prior IPCC reports. The numerical 
suffixes (e.g., 2-4.5 and 5-8.5) represent the approximate level of 
radiative forcing (the change in energy flux in the atmosphere caused 
by natural or anthropogenic factors of climate change) in 2100 
(compared to preindustrial levels) in units of watts per meter squared 
(W/m\2\). The SSP2-4.5 pathway (modest mitigation) used in this 
analysis is similar to the RCP 4.5 scenario used in past reports, 
whereas the SSP5-8.5 pathway represents one of the most pessimistic 
estimates of future greenhouse gas emissions, a future with no 
mitigation policy. The SSP5-8.5

[[Page 83750]]

pathway was included in this analysis to provide a lower-boundary 
estimate of future snow cover available for wolverines within the 
selected domains (OSTP 2023, p. 11). We chose a snow depth threshold of 
greater than or equal to 1 m (40 inches) to represent persistent spring 
snow cover on May 1 based on published literature, our prior analyses 
in the 2018 SSA, and studies indicating that den site abandonment 
generally occurs before May 1 (see the Use of Dens and Denning Behavior 
discussion in the Reproduction and Growth section of the 2018 SSA 
(Service 2018, pp. 25-27). There is no known snow depth threshold for 
successful wolverine denning on any date. However, based on historical 
den site melt-out dates (when there was no snow at the den sites) and 
hindcasted (historical) snow models for Glacier National Park, the 2018 
SSA used greater than 0.5 m (20 inches) on May 1. We received criticism 
from some wolverine researchers that the use of the 0.5-m snow depth 
threshold on May 1 was not conservative enough based on prior studies 
(e.g., Copeland et al. 2010, entire; McKelvey et al. 2011, entire) that 
considered snow depth out to June. Others would argue (based on the 
importance of snow for denning) that snow depth at May 1 is not as 
important since young wolverine kits are usually out of their natal 
dens by mid-March (Inman 2023, pers. comm.). To address the criticism, 
and to acknowledge that snow is likely important to the wolverine for 
more life behaviors than just denning, for our updated analysis we 
increased the snow depth measure representing persistent snow cover to 
greater than or equal to 1 m (3.3 ft) but retained the May 1 end date. 
This provides a reasonable but more conservative estimate than we used 
in the 2018 SSA.
    Results from this updated climate change analysis are consistent 
with earlier studies predicting greater snow loss at lower elevations 
across all domains. Similar elevational patterns were reported for 
Rocky Mountain and Glacier National Parks with greater reductions in 
future snow cover at lower elevations (Barsugli et al. 2020, pp. 8-10). 
This is partially explained by a greater percentage of future 
precipitation falling as rain due to higher temperatures, earlier 
snowmelt onset, and warmer conditions. Snowpack in the high country is 
not as affected by projected temperature increases but is likely more 
strongly controlled by projected precipitation changes (Barsugli et al. 
2020, pp. 6-11; Scalzitti et al. 2016, p. 5367; Sospedra-Alfonso et al. 
2015, p. 4429).
    The elevational distribution of historical den sites varies by 
latitude, with a general trend of dens being found at higher elevations 
the farther south they are found. For example, dens in the Northern 
Rocky domain are found at elevations ranging from approximately 1,500-
2,400 m (4,921-7,874 ft) (Service 2023, figure 12), while dens in the 
Mid-Rocky domain are found from approximately 2,400-3,000 m (7,874-
9,843 ft) (Service 2023, figure 13). Additional den sites outside of 
the modeling domains could expand these elevational bands. The majority 
of historical dens across the domains are located in elevational bands 
that are predicted to experience relatively small decreases in future 
snow cover at the higher denning elevations and moderate decreases for 
lower denning elevations. The percentage change in future snow depth 
threshold (greater than or equal to 1 m (3.3 ft)) on May 1 (median) for 
SSP2-4.5 (2076-2095) for the upper denning elevations in Northern Rocky 
West, Northern Rocky, and Mid-Rocky domains is predicted to be a less 
than 10 percent decrease, whereas the percentage change for the 
Cascades domain is predicted to be a less than 25 percent decrease. The 
percentage change in future snow depth threshold (greater than or equal 
to 1 m (3.3 ft)) on May 1 (median) for SSP2-4.5 (2076-2095) for the 
lower denning elevations in Northern Rocky is predicted to be a 10-50 
percent decrease, and for Mid-Rocky is predicted to be a 10-25 percent 
decrease, while the percentage change for the Cascades domain is 
predicted to be a less than 25 percent decrease.
    Elevations above historical den elevations are predicted to have 
small decreases (less than 10 percent) in the future area with snow 
depth exceeding the threshold (greater than or equal to 1 m (3.3 ft)) 
on May 1 (median) for SSP2-4.5 (2076-2095) across the domains and in 
some cases (e.g., Northern Rocky and Mid-Rocky domains), there are 
increases in predicted future area with snow exceeding the greater than 
or equal to 1 m (3.3 ft) May 1 threshold. This is driven by the 
increases in future precipitation expected in all five domains, and 
elevations with temperatures sufficiently cold enough to sustain 
snowfall, even with future warming. The lowest elevation areas within 
all domains (the lowest approximately 500 m (1,640 ft) of domains 
modeled) are predicted to have the greatest decreases in the future 
snow depth threshold (greater than or equal to 1 m (3.3 ft)) on May 1. 
For example, the Northern Rocky domain is predicted to experience 
decreases of 50 to 100 percent at 1,000-1,500 m (3,281-4,921 ft) of 
elevation (Service 2023, figure 13). Similar patterns are seen in the 
other four domains, including predicted changes (mostly negative) in 
the future snow depth threshold (greater than or equal to 1 m (3.3 ft)) 
on May 1. While decreases are projected across the domains, the 
specific thresholds that could impact wolverine persistence at the 
population level are not known.
    Central to our assessment of future conditions is the degree to 
which changes in persistent spring snow, other snow dynamics (e.g., 
volume, duration, condition, spatial and temporal variability, etc.), 
and other climate-related factors will impact wolverines at the 
population level in the contiguous United States. Key uncertainties 
that remain regarding these relationships include: (1) the extent to 
which wolverine population connectivity and gene flow will be affected 
by these changes; (2) the impacts of climate change on ecosystem 
drivers of wolverine persistence (i.e., changes in community dynamics, 
including prey availability and competition with other predators that 
might impact wolverine demographic rates); (3) the volume and duration 
of snow required for wolverines to successfully acquire and cache food 
for future use; (4) the impacts of climate change on the ability of 
wolverines to thermoregulate, and whether wolverines might experience 
any sublethal effects from changes in temperature (e.g., impacts to 
reproduction) (see Thiel et al. 2019, entire); (5) whether the observed 
associations of the wolverine's distribution with snowy and cold 
environments are driven by reproductive denning needs, other ecological 
requirements, or physiological constraints (Aubry et al. 2023, p. 16); 
(6) the adaptive capacity of wolverines to move to higher elevations 
for denning given predicted snow loss at lower elevations within their 
historical denning range (assuming snow is required for denning); and 
(7) the importance of snow and the impact of decreases in future snow 
within historical denning elevations on reproductive success. In 
summary, specific thresholds regarding snow dynamics and how changes in 
these factors will impact wolverines in the future at the population 
level remain uncertain.
    That said, we know that wolverines are a species that is adapted 
to, and has a strong preference for, cold and snowy conditions and that 
these conditions occur in the contiguous United States at high 
elevations. As explained before,

[[Page 83751]]

there are uncertainties as to the exact mechanism(s) by which spring 
snowpack is important to wolverines or when it may become limiting. 
Although wolverines have been shown to den outside of spring snowpack 
in Canada and Scandinavia, we continue to have no evidence of this 
behavioral ability in the contiguous United States. Furthermore, new 
research on wolverine habitat use continues to reinforce that cold and 
snowy conditions are a strong predictor of wolverine occurrence on the 
landscape (Aubry et al. 2023, pp. 15-16; Carroll et al. 2020, p. 8; 
Fisher et al. 2022, p. 10; Glass et al. 2021, entire; Mowat et al. 
2020, p. 220). Furthermore, deep, persistent snow cover has been shown 
to be an important predictor of successful wolverine dispersal and 
resulting genetic structure (Balkenhol et al. 2020, pp. 798-799). New 
research on food caching indicates that warming future conditions could 
make caching food, a year-round behavior, more difficult for wolverines 
(Van der Veen et al. 2020, pp. 8-10). As climate change reduces the 
preferred habitat conditions for wolverine, it has the potential to 
exacerbate other stressors discussed above including effects from 
roads, winter recreational activity, effects from development, low 
genetic diversity, and small population effects. When taken together, 
we have no reason to conclude that wolverines will somehow continue to 
have the same or better resiliency in the contiguous United States in 
the future when those cold and snowy conditions at high elevations are 
expected to decrease, with spring snowpack at denning elevations 
decreasing as much as 50 percent in some areas. Although we are not 
seeing deleterious effects of climate change on the contiguous U.S. DPS 
of North American wolverines currently, we expect future impacts at the 
population level.
    Effects from Roads: In our 2018 SSA and the October 13, 2020, 
withdrawal document (85 FR 64618), we concluded that roads present a 
low stressor to wolverines at the individual and population level in 
most of the wolverine's current area of occupancy within the contiguous 
United States. New information on the effects of roads on the North 
American wolverine's distribution, density, reproduction, and 
connectivity and gene flow are presented below.
    Since 2018, we were made aware of four wolverine mortalities from 
collisions with vehicles in the contiguous United States, at least 
three of which were males (Service 2023, p. 30). Overall, young, 
inexperienced male wolverines have a greater risk of road mortality 
during dispersal compared to adults and immature females that are less 
prone to long-distance dispersal (e.g., Krebs et al. 2004, pp. 497-
498). The small number of mortalities observed since 2018, if biased 
toward males, are unlikely to have substantial impacts to the 
resiliency of the DPS overall.
    New studies available in southwestern Canada and the western United 
States since the 2018 SSA have found that North American wolverine 
distribution and density are negatively related to road density 
(Service 2023, pp. 31-32). In southwestern Canada, consistency of 
spring snow and road density are the two most important variables 
correlated with wolverine density (Clevenger 2019, p. 52; Mowat et al. 
2020, p. 220). Wolverine population estimates derived from models based 
on snow and road density predicted that wolverine abundance would be 44 
percent higher without the depressing effect of the road covariate 
(Clevenger 2019, p. 52; Mowat et al. 2020, p. 220). As most roads are 
concentrated in areas of human development at lower elevations with 
less snow, correlations between wolverine distribution and road density 
can be confounded by other collinear variables (Copeland et al. 2007, 
pp. 2210-2211). In southeastern British Columbia, the density of forest 
roads that extended into high-elevation wolverine habitat was a strong 
negative predictor of wolverine distribution in winter, especially for 
females (Kortello et al. 2019, p. 10). The most likely explanation for 
this negative relationship is the use of these high-elevation forest 
roads by snowmobilers, rather than predator avoidance or trapping 
pressure (Kortello et al. 2019, p. 10). Other possible explanations are 
increased trapping access or less abundant food resources near roads 
(Mowat et al. 2020, p. 224). While the statistical significance of the 
relationship between roads and wolverine densities has been 
demonstrated in some areas, the mechanisms behind this relationship 
require further study (Mowat et al. 2020, p. 224).
    Large transportation corridors (e.g., multi-lane highways with 
substantial traffic volume) can have a significant impact on wolverine 
population connectivity and gene flow. The mechanisms for reducing 
connectivity and gene flow are road mortality and reduced habitat 
permeability (avoidance of crossing roads). Mitochondrial and nuclear 
DNA measures of genetic population structure found that the Trans-
Canada Highway corridor in the Canadian Rockies, as well as other 
natural and anthropogenic barriers to movement, fragmented the North 
American wolverine population by restricting female movement (Sawaya et 
al. 2019, pp. 621-622). This restricted movement resulted in male-
biased dispersal and gene flow (Sawaya et al. 2019, pp. 621-622). This 
highway is approximately 150 miles north of the U.S.-Canada border, and 
the study area for analyzing wolverine movement across the Trans-Canada 
Highway was in the lower Bow River Valley, which is a human-dominated 
landscape containing the Trans-Canada Highway, a town with 
approximately 10,000 residents, a golf course, three ski areas, the 
Canadian Pacific Railway, and a secondary highway. This transportation 
corridor was not an absolute barrier to female movement (4 of 20 female 
wolverines crossed the highway during the study); however, females 
traversing the transportation corridor did not translate to gene flow 
(Sawaya et al. 2019, p. 622). The differences between male and female 
dispersal across this highway were likely due to the exacerbating 
effects of linear anthropogenic barriers on the strong natural 
tendencies for female wolverine philopatry (tendency to return to or 
remain near a particular area or site) (Sawaya et al. 2019, p. 623). 
(See Genetic Diversity, below, for more discussion of the effects of 
roads on gene flow and genetics of wolverines within the contiguous 
United States and genetic connectivity to Canada).
    Wildlife crossing structures spanning the Trans-Canada Highway 
along the crest of the Continental Divide may improve wolverine 
connectivity across this highway. Evidence suggests that female 
wolverines may be starting to use wildlife crossings to cross the 
Trans-Canada Highway (Service 2023, p. 32). However, the efficacy of 
these structures in restoring gene flow has not yet been measured 
(Sawaya et al. 2019, p. 623). There are few wildlife crossing 
structures spanning major highways in the contiguous United States; a 
series of three under-crossings and one dedicated wildlife overpass on 
I-90 in the Washington Cascades (connecting the northern and southern 
Cascades) were completed in 2019 (Sugiarto 2022, p. 9). To date, 
however, no wolverines have been detected using these relatively new 
crossings.
    Habitats in the contiguous United States outside of the known 
breeding distribution of wolverines, including the Sierra Nevada in 
California and the central Rocky Mountains in Colorado, are separated 
from occupied habitats by

[[Page 83752]]

large expanses of high-resistance habitats, anthropogenic features, and 
highways (e.g., Carroll et al. 2020, pp. 9-10; Bjornlie et al. 2021, 
pp. 116-117). While highways are not an absolute barrier to movement 
(wolverines have been documented crossing multi-lane highways), they 
can apparently limit female wolverine gene flow in some situations 
(e.g., Sawaya et al. 2019, pp. 621-622). The wolverine's capacity to 
traverse large expanses of high-resistance habitats, anthropogenic 
features, and highways and naturally recolonize and establish a 
population in some relatively isolated habitats in the contiguous 
United States (e.g., Oregon Cascades, Sierra Nevada, and central Rocky 
Mountains) remains unclear.
    Based on the best available scientific and commercial information, 
the effect of roads, in isolation, represents a relatively low threat 
to wolverines in the contiguous United States at the population level, 
although some individuals are affected. However, in combination with 
other threats discussed below, roads, in particular multi-lane, high-
traffic roads, and high road density in core habitats could negatively 
affect the North American wolverine's population resilience, 
distribution, and gene flow in the future.
    Disturbance Due to Winter Recreational Activity: In our 2018 SSA 
and October 13, 2020, withdrawal document (85 FR 64618), we concluded 
that the effect of winter recreational activity represents a low 
stressor to wolverines in the contiguous United States at the 
individual and population levels. New information on winter recreation 
impacts on North American wolverines is presented below and adds 
significantly to our understanding of this factor as highly relevant to 
the DPS.
    The response of North American wolverines to various levels of 
backcountry winter recreation (motorized and nonmotorized) was recently 
studied in four areas in Idaho, Montana, and Wyoming (Heinemeyer et al. 
2019a, p. 8). The study found that wolverines temporarily avoided areas 
within their home range where winter recreation (motorized and 
nonmotorized) was occurring (Heinemeyer et al. 2019a, p. 16). 
Wolverines increasingly avoided these areas as the amount of off-road 
winter recreation increased, resulting in indirect habitat loss or 
functional degradation of moderate- or high-quality habitats in winter 
(Heinemeyer et al. 2019a, p. 16). However, wolverines did demonstrate 
the ability to maintain multi-year home ranges despite the presence of 
winter recreation activity within those home ranges. Some resident 
animals had more than 40 percent of their home range within the 
footprint of winter recreation, suggesting that, at some scale, 
wolverines tolerate winter recreation (Heinemeyer et al. 2019a, p. 16).
    Dispersed or off-road winter recreation appears to elicit more of 
an avoidance response than recreation along roads and groomed routes 
with females showing more sensitivity than males (Heinemeyer et al. 
2019a, p. 15). Females exhibited more of a negative response to 
motorized recreation, which occurred at higher intensity across a 
larger footprint than did nonmotorized recreation.
    In a study evaluating the strength of aerial survey metrics in 
predicting wolverine responses to motorized and nonmotorized 
backcountry winter recreation, higher recreation intensity showed 
stronger avoidance coefficients and were the most important modelled 
predictors of female wolverine absence (Heinemeyer et al. 2019b, pp. 
18-20). Given the likelihood that, under climate change, both 
wolverines and backcountry winter recreation will be impacted by 
declining snow extent and depth and an abbreviated snow season, there 
is the potential for increased overlap between winter recreation and 
wolverine distribution (Heinemeyer et al. 2019a, p. 18).
    The impacts of motorized and nonmotorized backcountry winter 
recreation on wolverines in the Nez Perce-Clearwater, Sawtooth National 
Recreation Area, and Salmon-Challis National Forests of Idaho were 
recently evaluated (Regan et al. 2020, entire). Preliminary results 
showed that recreational impacts, in both area and intensity, are 
increasing over time. In the Sawtooth-Boulder White Cloud Mountains, 
researchers compared the current extent of winter recreation with known 
historical wolverine home ranges and found that most of these home 
ranges contained little or no backcountry recreation at this time 
(Regan et al. 2020, p. 4). In contrast, recent surveys on the Payette 
National Forest in central Idaho revisited a portion of a previous 
winter recreation study and found that there had been an incremental 
loss of resident wolverines from 2010 to 2014, and that previously 
documented territories appeared to be vacant (Mack and Hagen 2022, p. 
13). The authors suggest that ``what was considered to be a stable core 
subpopulation area could, in fact, be more tenuous'' and ``that the 
change in wolverine abundance in this area might be attributed to 
changes in habitat quality from direct or indirect influences including 
dispersed recreation,'' although the cause for the decline in wolverine 
abundance requires further study (Mack and Hagen 2022, p. 13).
    Both motorized and nonmotorized recreation can affect wolverine 
habitat use. Forest roads that are used by snowmobilers appear to have 
a strong negative correlation with wolverine distribution (Kortello 
2019, p. 10). Nonmotorized recreation can also impact wolverines. 
Remote camera-based surveys from 2011-2020 in protected and non-
protected habitat in southwestern Canada found that wolverine detection 
probability was strongly negatively correlated with the amount of 
nonmotorized human recreation (Barrueto et al. 2022, pp. 4-8). This 
pattern was consistent in both winter and summer, and mirrored the 
findings of Heinemeyer et al. (2019a, p. 18). Further research is 
necessary to determine the specific causal mechanisms most responsible 
for these declines (Barrueto et al. 2022, p. 8).
    In the winter recreation studies we considered, winter recreation 
activities varied in the number of recreationists and types of 
recreation, and each study area had a unique combination of backcountry 
recreation including snowmobile, skiing (including snowboards), 
snowmobile-accessed ski/snowboard, cat-ski, heli-ski, yurt-supported 
skiing, and snowshoeing. Backcountry motorized and nonmotorized winter 
recreation that occurs in areas that do not overlap with wolverine home 
ranges is not expected to impact the DPS. Additionally, developed ski 
slopes and resorts that are already on the landscape and other 
developed winter recreation sites that do not occur in the backcountry 
are not expected to be a concern for wolverines, as wolverines are 
likely already avoiding these areas. Backcountry winter recreational 
activities that do occur in wolverine home ranges could negatively 
impact wolverines by displacing them from high-quality habitat. 
Developed ski resorts that allow for backcountry or out-of-bounds 
skiing in areas that overlap wolverine home ranges may also displace 
wolverines. Backcountry areas where wolverines reside in winter are 
largely difficult for recreationalists to access without snowmobiles or 
forest roads that facilitate access, and the intensity of recreational 
activity is correlated with accessibility.
    Based on the best available scientific and commercial information, 
the effect of winter recreation activity (of greatest concern because 
of potential to impact denning), in isolation, represents a low

[[Page 83753]]

threat to North American wolverines in the contiguous United States at 
the population level, although some individuals are affected. However, 
in combination with other threats, including decreased snow 
availability (see Climate Change, above) and increased overlap with 
winter recreationalists in the future of climate change, winter 
recreation could negatively affect wolverine population resilience in 
the future.
    Other Human Disturbance and Development: In our 2018 SSA and 
October 13, 2020, withdrawal document (85 FR 64618), we concluded that 
human infrastructure may affect individual wolverine behavior (e.g., 
avoidance) or result in the loss or modification of wolverine habitat. 
We further stated these effects are small or narrow in scope and scale 
and appear to represent a trade-off between foraging opportunities in 
areas that provide minimal risk of predation and avoidance of open 
areas and/or higher predation risk. We discuss below new information 
related to the impacts of human disturbance and development on North 
American wolverine populations.
    North American wolverine density in and around a national park 
complex in the southern Canadian Rocky Mountains was three times higher 
within these national parks than outside them, increased with spring 
snow cover, and decreased with increasing night light intensity (a 
measure of human development) (Barrueto et al. 2022, p. 4). An 
approximately 40 percent decline in wolverine abundance was observed 
between 2011 and 2020, likely from one or more of the following causes: 
trapping, backcountry recreation, human development, and food 
availability (Barrueto et al. 2022, pp. 4, 6-8). This pattern is 
consistent with telemetry-based data that wolverines avoid 
infrastructure (May et al. 2006, entire; Scrafford et al. 2018, 
entire). Along the Front Range of the Canadian Rocky Mountains, 
wolverines selected areas with natural land-cover and high snow cover, 
and avoided anthropogenic features and heterospecific competitors (Heim 
et al. 2019, pp. 2499-2502). It is thought that competition from other 
carnivores that more readily exploit anthropogenic change may 
exacerbate the habitat loss and displacement impacts of such changes on 
North American wolverines (Heim et al. 2019, pp. 2503-2504).
    Connectivity among North American wolverine habitats appears to be 
particularly sensitive to housing developments and other human impacts 
in rugged areas located between typical wolverine habitats (Balkenhol 
et al. 2020, p. 799). Housing density was found to be an important 
predictor of long-distance wolverine dispersal and population structure 
in the Northern Rocky Mountains (Balkenhol et al. 2020, p. 799). Even 
if areas between wolverine primary alpine habitats are not typically 
inhabited by wolverines, they may be used during dispersal and can, 
therefore, offer crucial pathways for gene flow across broad spatial 
scales (Balkenhol et al. 2020, p. 799).
    The extent of the impacts of human presence and actions on the 
landscape have been collectively called ``the human footprint'' (Janzen 
1998, entire). In an analysis of the human footprint in the western 
United States, Leu et al. (2008, p. 1125) found that the physical 
effect area of 14 anthropogenic features they analyzed (human 
habitation, interstate highways, Federal and State highways, secondary 
roads, railroads, irrigation canals, powerlines, linear feature 
densities, agricultural land, campgrounds, highway rest stops, 
landfills, oil and gas development, and human-induced fires) covered 13 
percent of the land area in the western United States. Accounting for 
the indirect effects radiating out from the direct human footprint, Leu 
et al. (2008, p. 1125) categorized 52 percent of the western United 
States as having medium- or high-intensity impacts from the human 
footprint (both direct and indirect impacts), while low-intensity 
impact areas covered the remaining 48 percent of the landscape (Leu et 
al. 2008, pp. 1125-1127). When modeled North American wolverine core 
areas are overlaid across the western United States with the human 
footprint, less than 1 percent was in the high-intensity category, 12 
percent in the medium-intensity category, and 88 percent in the low-
intensity category. We also overlaid the current breeding distribution 
of the North American wolverine with the human footprint map and found 
that only 1 percent of the current breeding range was within the high-
intensity category, 31 percent in the medium-intensity category, and 68 
percent in the low-intensity category (Service 2023, figure 4). As 
expected, wolverine core areas are concentrated in high-elevation areas 
with little human infrastructure (Service 2023, figure 4). However, 
within their current breeding distribution in the contiguous United 
States, wolverines must navigate across lower elevation areas with 
greater amounts of human infrastructure to disperse from one habitat 
core to another (Service 2023, figure 4).
    In addition to effects on wolverine density and connectivity, human 
infrastructure can also affect wolverines through shifts in community 
dynamics that precipitate from changes in the behavior and temporal use 
of habitats by apex predators. Wolverines and other carnivores may 
shift their daily behavior patterns in response to the presence of 
human landscape disturbance (Frey et al. 2020, pp. 1133-1138). Indirect 
effects can also include range expansion of other carnivores into 
wolverine habitat facilitated by human infrastructure. While wolverine 
and coyotes are generally segregated, the probability of co-occurrence 
increases with the proportion of linear disturbance features (Chow-
Fraser et al. 2022, p. 4). Using a study area in Alberta (Frey et al. 
2020, p. 1130), the authors found that while wolverines favored areas 
of low disturbance (low proportion of linear features) and coyotes 
favored areas of high disturbance (high proportion of linear features), 
co-occurrence probability increased 3 times for each increase of linear 
feature unit (Chow-Fraser et al. 2022, p. 4). Modeling showed that 
competition exhibited the strongest effect on wolverine distribution, 
with wolverine occurrence best explained by coyote occurrence at the 
same sites (Chow-Fraser et al. 2022, p. 4). These results suggest that 
anthropogenic disturbance and resulting coyote range expansion may be 
contributing to wolverine population declines in the Canadian Rocky 
Mountains (Chow-Fraser et al. 2022, p. 6).
    A recent study estimated the independent and cumulative effects of 
landscape features, human disturbance (distance to human settlements 
and roads, night light brightness, human population density), and prey 
availability on wolverines and other large carnivore occurrences in 
Fennoscandia (region in Europe that includes the Scandinavian 
peninsula, the Kola Peninsula, mainland Finland, and Karelia) (Milanesi 
et al. 2022, entire). Contrary to the other carnivores they evaluated, 
variation in the ``permanent'' occurrence of wolverines was best 
explained by human disturbance and the shared effect between landscape 
attributes and human disturbance. This same relationship was observed 
for ``sporadic'' wolverine occurrences, but with a considerably lower 
level of explained variance. The researchers concluded that, ``the 
wolverine showed higher sensitivity to human disturbance compared to 
the other large carnivores, and spatial segregation patterns between 
wolverines and humans were found, as large carnivore home ranges are 
usually at high elevation (often covered by

[[Page 83754]]

snow), far from the lowlands where density of human settlements and 
roads is high'' (Milanesi et al. 2022, p. 10). It appears that 
wolverines select den sites mainly away from infrastructure, indicating 
that successful reproduction may be influenced by human activities. 
However, wolverines also appear to be able to cross artificial barriers 
to some degree. Therefore, wolverines appear to have a relatively low 
tolerance of human disturbance, with an ability to exhibit more 
flexible behavior during dispersal in some circumstances.
    Human disturbance and development effects are limited in scope and 
scale within the wolverine DPS's core habitats and breeding range in 
the contiguous United States. However, in lower elevations and valleys 
bottoms between core habitats, wolverines must traverse through areas 
of human disturbance and infrastructure to maintain connectivity in the 
contiguous United States, where habitat is often fragmented. Wolverines 
have shown avoidance of disturbed areas and human infrastructure and a 
preference for habitats devoid of these features. Based on the best 
available scientific and commercial information, we find that human 
disturbance and development, especially coupled with major roads (see 
Effects from Roads, above), could limit wolverine connectivity and 
dispersal in the future.
    Effects from Wildland Fire: In our 2018 SSA and October 13, 2020, 
withdrawal document (85 FR 64618), we found that wildland fire was 
neither a population- nor species-level stressor to North American 
wolverines in the contiguous United States. Our assessment of wildland 
fire effects to wolverines has not changed. 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). Wildland fire is likely to 
temporarily displace wolverines, which could affect home range 
dynamics. Given that 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 their extensive mobility, 
wildland fire does not represent a stressor to North American 
wolverines in the contiguous U.S. range (Service 2018, pp. 63-64) and 
is not expected to have population-level impacts.
    Disease and Predation: In our 2018 SSA, we found that disease and 
predation were neither population- nor species-level stressors to the 
North American wolverine in the contiguous United States. Our 
assessment of these stressors has not changed.
    There has been considerable localized research on diseases and 
parasites in wolverines since the 2018 SSA was published; however, we 
lack data on the specific effects to wolverine populations. It is 
conceivable that disease-induced mortality could contribute to 
population declines, but this remains understudied south of the Arctic 
(Fisher et al. 2022, p. 9). The types of bacteria or parasites that 
could lead to disease in wolverines are still unknown (Watson 2020, pp. 
62, 65). Many authors have discovered new viruses in the United States 
and Canada, some of which were previously unrecognized species of 
parasites (Sharma et al. 2020, p. 277; 2021, p. 1; Watson et al. 2020, 
p. 43; Bandoo et al. 2021, p. 1). This new information pertains to how 
wolverines act as primary hosts for some parasites, such as Trichinella 
spp., and how those parasites could increase infection risk to humans 
and other vertebrates (Sharma et al. 2021, pp. 1, 7). Considering the 
global coronavirus pandemic in recent years and instances of human-
animal cross-infections, researchers are beginning to use genomic data 
to evaluate the wolverine's susceptibility to these pathogens (Lok et 
al. 2022, pp. 16-18). Although no coronavirus cases have been reported 
in wolverines, and an initial evaluation of the wolverine's genome to 
determine susceptibility to coronaviruses was inconclusive, there is 
potential risk of infection from their prey or from researchers 
handling captured wolverines that they release back into the wild (Lok 
et al. 2022, pp. 16, 18, 20).
    Since our 2018 SSA, we found no substantive new information on 
predation. In North America, there was one new report of two wolverines 
being predated upon in the boreal ecosystem of Canada. One was the 
result of wolf predation, and the other was the result of an unknown 
predator (Scrafford et al. 2021, p. 9).
    Based on the best available scientific and commercial information, 
disease and predation are not threats to North American wolverines in 
the contiguous United States at the individual or population level.
    Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes: In our 2018 SSA and October 13, 2020, withdrawal 
document (85 FR 64618), we concluded that overutilization does not 
currently represent a stressor to the wolverine in the contiguous 
United States at the individual, population, or species level. We also 
concluded that trapping in Canada had been and appeared to be 
sustainable, and trapping or harvesting of wolverines along the 
contiguous U.S.-Canada border did not represent a barrier to wolverine 
movement and dispersal along the international border (Service 2018, p. 
71). Below, we present new information on incidental captures of 
wolverines in the contiguous United States, where regulated wolverine 
trapping remains closed (Service 2018, pp. 70-72), and new information 
on the effects of trapping mortality on wolverine populations in 
southwestern Canada. New information suggests that wolverine trapping 
in southwestern Canada has impacted connectivity across the 
international border.
    Since 2012, there have been 10 nontarget wolverine captures 
(average = fewer than 1 per year (1/year)) in Montana, resulting in 3 
mortalities (1 in a conibear (a body gripping trap), 1 in a foothold, 
and 1 in a snare); the remainder were released (MFWP 2023, in litt., p. 
1). In Idaho, 14 nontarget captures (0.7/year) of wolverines have 
occurred during licensed trapping activities, with no demonstratable 
trend in capture rates over the past 20 years (IDFG 2022, in litt., p. 
3). Nine wolverines were incidentally trapped in Idaho between November 
2017 and August 2022, with two resulting in known mortalities (IDFG 
2022, in litt., pp. 5, 16-22).
    The Idaho legislature revised the Idaho Code (IC) in 2021 to: (1) 
authorize a year-round trapping season for wolves on private property 
(IC 36-201(3)); (2) authorize additional methods of take previously 
prohibited (inclusive of the use of snares in 97 out of 99 management 
units) (IC 36-201(2)); (3) remove any limit to the number of wolf tags 
an individual may purchase (IC 36-408(1)); (4) allow a livestock or 
domestic animal owner to use a private contractor to kill wolves (IC 
36-1107(c)); (5) allow the Idaho Wolf Depredation Control

[[Page 83755]]

Board to enter into agreements with private contractors, in addition to 
State and Federal agencies, to implement the provisions of Idaho Senate 
Bill 1211 (IC 22-5304(2)); and (6) direct wolf control assessments 
($110,000 annually) collected from the Idaho livestock industry to be 
combined with $300,000 the State will transfer from the IDFG fund 
annually beginning on July 1, 2021 (IC 22-5306).
    In Montana, new laws were also passed in 2021 to reduce the wolf 
population through, among other things: (1) authorizing the use of 
snares to take wolves by licensed trappers (Montana Code Annotated 
(MCA) 87-1-901(2)(b)); (2) allowing the Montana Fish, Wildlife, and 
Parks (MFWP) Commission authority to extend trapping season dates (MCA 
87-1-304(8)); and, (3) allowing the reimbursement of costs incurred to 
harvest a wolf or wolves in Montana (MCA 87-6-214(1)(d)).
    These regulation changes may increase the amount of wolf trapping 
and the risk of incidental trapping of wolverines because of the use of 
snares, extended trapping seasons, and financial incentives. However, 
because wolverines differ from wolves in size, distribution, and 
behavior, trappers use pan tension, site selection, and snare height to 
reduce the likelihood of incidental capture. In addition, year-round 
wolf trapping seasons in Idaho are limited to private lands, where 
there is very little core wolverine habitat. Although the wolf trapping 
regulations have been in effect for a limited time, we do not 
anticipate a significant increase in wolverine incidental trapping due 
to the measures Idaho and Montana are taking to limit wolverine 
capture. Across the contiguous U.S. range, wolverine mortality from 
incidental trapping has historically been very low, and States within 
the DPS's range are actively taking measures to limit incidental 
capture and mortality. Below, we present a summary of incidental 
trapping risk and measures to limit wolverine capture for each State 
within the current range in the contiguous United States.
California
    The wolverine is listed as both a threatened species and as a fully 
protected mammal in California; these designations provide wolverines 
broad protection from being trapped, killed, or otherwise taken in the 
State (CDFW 2023, in litt., p. 2). Recent detections of lone animals 
have indicated the occasional presence of wolverines in the State (CDFW 
2023, in litt., p. 2). Recreational and commercial trapping of fur-
bearing and nongame animals has been illegal in California since 2019 
(CDFW 2023, in litt., p. 2). While furbearers and nongame species can 
be trapped for other reasons (e.g., the protection of property), 
existing regulations likely preclude the serious injury or mortality of 
incidentally captured wolverines (CDFW 2023, in litt., p. 2). The use 
of snares, conibear-type traps, and deadfall traps is prohibited in 
large areas of the State, including in the most recently estimated 
historical range of the wolverine (CDFW 2023, in litt., p. 2). The use 
of steel-jawed leghold traps is prohibited throughout the State (CDFW 
2023, in litt., p. 2). All traps must be checked daily, and all 
captured animals that are not legal to trap should be immediately 
released (CDFW 2023, in litt., p. 2).
Colorado
    Recreational trapping of wildlife in Colorado is limited to live 
cage traps (CPW 2023, in litt., p. 1), and any wolverines incidentally 
trapped could be released unharmed. However, there are currently no 
wolverines known to be present in Colorado, and, therefore, there 
should be no incidental trapping of wolverines occurring (CPW 2023, in 
litt., p. 1).
Idaho
    IDFG has multiple guidelines that are shared with the trapping 
community to reduce the nontarget capture of wolverine (IDFG 2023, in 
litt.; IDFG 2022, p. 40). The guidelines, developed with the assistance 
of technical experts familiar with the wolverine, include 
recommendations on the types of traps used, trap tension, trap 
placement, avoiding areas with wolverine tracks observed, selecting 
habitats less likely to have wolverines, and contacting IDFG or a local 
sheriff's office to assist with the safe release of wolverines 
incidentally trapped. These guidelines help minimize nontarget 
wolverine captures (IDFG 2023, in litt., p. 3). Capture rates of 
wolverine during trapping activities for other species are low. In 
Idaho, 14 nontarget captures (0.7/year) of wolverines have occurred 
during licensed trapping activities, with no demonstratable trend in 
capture rates over the past 20 years (IDFG 2022, in litt., p. 3). 
Between November 2017 and August 2022, IDFG reported that nine 
wolverines were incidentally trapped, with two resulting in mortalities 
(IDFG 2022, in litt., pp. 5, 16-22).
Montana
    Montana FWP has multiple trapping regulations that help mitigate 
the nontarget capture of wolverines by recreational trappers (MFWP 
2023, in litt., p. 1). The regulations include requirements for 
trappers to take an education course, that wolf traps must be checked 
every 48 hours, and that wolf trap tension and snare height are set to 
limit wolverine capture (MFWP 2023, in litt., p. 1). There are also a 
number of regulations required to mitigate the nontarget capture of the 
federally listed Canada lynx (Lynx canadensis) that are also applicable 
to wolverines, including the prohibition of wolf snares on public lands 
in lynx protected zones, which overlap much of the wolverine habitat in 
Montana (MFWP 2023, in litt., p. 5).
    The last legal harvest season for wolverines in Montana was in 2012 
(MFWP 2023, in litt., p. 1). The nontarget capture of a wolverine is 
very rare, and these incidents do not pose any population-level effects 
on wolverines (MFWP 2023, in litt., p. 1). There have been 10 nontarget 
wolverine captures (average = less than 1/year), resulting in 3 
mortalities in Montana (MFWP 2023, in litt., p. 1). This also provides 
evidence of the efficacy of the trapping regulations in place to 
mitigate the nontarget capture of wolverines and other animals (MFWP 
2023, in litt., p. 1).
Oregon
    There is no open season for wolverine (or other protected species), 
and any incidental capture or other take of wolverines must be reported 
to the Oregon Department of Fish and Wildlife (ODFW) within 48 hours 
(ODFW 2023, in litt., p. 4). Regulations that also reduce any 
incidental captures or take include a 48-hour trap check (which limits 
the ability for traps to be set in the wolverine's range and allows for 
prompt trap set modification or removal if signs of wolverine presence 
are detected) and a prohibition on medium-sized and larger body-grip 
traps (such as the conibear trap) being set on land (ODFW 2023, in 
litt., p. 4). In practice, other traps successfully deployed for the 
capture of wolverines simply are not used by Oregon trappers (ODFW 
2023, in litt., p. 4). For example, foothold traps (#4 coil springs, 
Minnesota Brand 750s) used for wolverine in Canada and Alaska are too 
large for targeted Oregon species like bobcats (Lynx rufus) and coyotes 
(ODFW 2023, in litt., p. 4). No wolverines have been incidentally 
captured by licensed furtakers in Oregon over the last half-century 
(ODFW 2023, in litt., p. 4).
Utah
    There are no regulations specific to wolverines in Utah, but the 
Utah Division of Wildlife Resources (UDWR)

[[Page 83756]]

regulates trapping and the use of trapping devices to reduce the 
capture of nontargeted protected species (UDWR 2023, in litt., p. 2). 
Any protected wildlife found alive in a trapping device must be 
immediately released unharmed (UDWR 2023, in litt., p. 2). UDWR also 
provides trappers with multiple recommendations that can help avoid 
catching nontarget species in traps set for bobcats and other 
furbearers, including recommendations on the type of traps used, 
placement of traps, and baits used (UDWR 2023, in litt., p. 2).
Washington
    Information on the wolverine is in Washington's trapping education 
manual, and all trappers must pass a trapper education test (or a 
similar one in another State) prior to obtaining their first license 
(Washington Department of Fish and Wildlife (WDFW) 2023, in litt., p. 
2). Due to Washington's trap-type regulations banning body gripping 
traps, the likelihood of accidental capture of a wolverine is very 
unlikely, and injury or death from these traps even more unlikely (WDFW 
2023, in litt., p. 2). In Washington, the most commonly trapped animal 
in habitats that wolverines occupy is the marten (Martes americana) but 
marten traps are too small for wolverines (even young wolverines) to be 
captured (WDFW 2023, in litt., p. 2). Larger cage traps that are used 
for bobcat and other larger animals could potentially capture a 
wolverine, but these are not commonly set in areas that wolverines 
occupy, and if a wolverine were incidentally captured, it could be 
released from the trap unharmed (WDFW 2023, in litt., p. 3). The past 
several years of trapper reports (2017-2022) do not show any records of 
a wolverine being trapped.
Wyoming
    The Wyoming Game and Fish Department (WGFD) addresses the 
incidental capture of animals classified as protected, like wolverines, 
in their Furbearing Animal Hunting or Trapping Seasons Brochure (WGDF 
2023, in litt., p. 4). All protected animals that are trapped shall be 
released unharmed and mortalities reported to the WGFD (WGDF 2023, p. 
14). Large areas of Wyoming within the distribution of wolverines are 
closed to trapping, including Yellowstone National Park and Grand Teton 
National Park.
    The WGFD is not aware of any wolverines trapped incidentally in 
Wyoming in recent history (WGDF 2023, in litt., p. 1). Trap types with 
the potential to capture wolverines are largely restricted to private 
lands, must be partially submerged in water (where there would be low 
likelihood of wolverine capture), or are required to have break-away 
devices to limit bycatch (WGDF 2023, in litt., p. 2). Trapping that 
occurs in areas that overlap with wolverine habitat in Wyoming is 
primarily by marten trappers that use smaller cubby trap sets, and it 
is unlikely these would capture a wolverine (WGDF 2023, in litt., p. 
2).
    Since our 2018 SSA, there is substantial evidence demonstrating 
that direct trapping of wolverines has impacted wolverine densities in 
southern British Columbia and Alberta over the last decade (e.g., 
Kortello et al. 2019, pp. 1, 10; Mowat et al. 2020, entire; Barrueto et 
al. 2020, p. 296; Barrueto et al. 2022, entire). In addition, there 
appear to be edge effects from trapping, with impacts to wolverine 
densities extending into protected areas in southern Canada (Barrueto 
et al. 2020, p. 296; Barrueto et al. 2022, p. 4). In the most expansive 
study of wolverine trapping and density to date--and encompassing 
southern British Columbia and Alberta's zone of connectivity with the 
Northern Rocky Mountains of the United States--wolverine trapping 
mortality was found to be unsustainably high at approximately 8.4 
percent per year (Mowat et al. 2020, p. 221). Kill rates were higher in 
the southern British Columbia portion of the study area, with the best 
estimate of trapping mortality there approaching 10 percent per year 
(Mowat et al. 2020, p. 223). This contrasts with the maximum 
sustainable harvest of approximately 8 percent after accounting for the 
influence of higher trap vulnerability of juveniles and males and 
stochasticity in juvenile recruitment rates (Mowat et al. 2020, p. 
221). Uncertainties in the stochasticity of reproduction, however, had 
large effects on the estimates of maximum sustainable harvest, causing 
it to vary between 0 and 8.1 percent (Mowat et al. 2020, p. 221). Based 
on their analyses, Mowat et al. (2020, p. 224) recommended reducing 
trapping mortality to no more than 4 percent per year (and perhaps even 
lower than that for an interim period) across their study area to 
promote wolverine population recovery. In response to the emerging 
information that trapping rates were unsustainable in southern British 
Columbia, the British Columbia Ministry of Forests, Lands, Natural 
Resource Operations and Rural Development closed a portion of the 
province along the U.S.-Canada border to wolverine trapping in 2020. 
New research published since that closure has confirmed population 
declines of approximately 40 percent (approximately 20 individuals) in 
the wolverine population in a portion of the Canadian Rocky Mountains 
over the decade before the closure (Barrueto et al. 2022, p. 6).
    Legal trapping of wolverines has not occurred in the contiguous 
United States in the past 10 years, and lethal incidental trapping of 
wolverines has been minimal (1 to 2 animals per year across the 
contiguous United States). As described above, States within the 
wolverine's range have implemented measures to limit the incidental 
trapping of wolverines during legal trapping of other wildlife. We 
expect that, as long as trapping is done in a manner to limit wolverine 
bycatch, recent changes to wolf trapping regulations in Idaho and 
Montana will have little effect on wolverines at a population level.
    Based on a recent analysis of an area in Canada that was 
experiencing population declines related to overharvest, Mowat et al. 
(2020, p. 224) recommended reducing direct trapping mortality to no 
more than 4 percent per year across their study area to promote 
wolverine population recovery. In the contiguous United States, where 
there is no direct trapping, incidental trapping rates have been well 
below this recommended rate. If we assume there are approximately 300 
wolverines in the contiguous United States and assume 2 wolverine 
mortalities per year from incidental trapping (a conservative estimate 
from the incidental trapping mortalities we know of since 2012), that 
would amount to only 0.67 percent of the population per year. This 
minimal level of loss will not significantly impact the contiguous U.S. 
population of North American wolverines and will not inhibit 
conservation of the DPS.
    As noted, trapping in southern Canada appears to be having more of 
a negative effect on wolverine populations in Canada than previously 
thought. Unsustainable trapping levels in Canada could limit dispersal 
of individuals into the contiguous United States, where the dispersal 
of wolverines from southern Canada is vital to the genetic and 
demographic health of the U.S. wolverine population. Based on the best 
available scientific and commercial information, the effect of 
overutilization (trapping) in the contiguous United States is not a 
threat to wolverines at the population level because there is no 
trapping of wolverine allowed, and the incidence of bycatch of 
wolverine resulting from other lawful trapping activities is small

[[Page 83757]]

and not expected to impact the DPS's population levels. However, in 
combination with other threats that limit dispersal (roads, 
infrastructure development, climate change), overharvest of wolverines 
in southern Canada could negatively affect the wolverine's population 
resilience, distribution, and gene flow in the contiguous United States 
in the future.
    Genetic Diversity: In our October 13, 2020, withdrawal document (85 
FR 64618), we conclude that loss of genetic diversity is not a threat 
for wolverines in the contiguous United States now or within the 
foreseeable future. Since our 2018 SSA and October 13, 2020, withdrawal 
decision, new genetic research has become available. Below, we assess 
new information on genetics relevant to our status assessment of 
wolverines in the contiguous United States, including estimates of 
effective population size and measures of gene flow and population 
connectivity.
Effective Population Size in the Contiguous United States
    As reported in our SSA report (Service 2018, pp. 46-47), effective 
population sizes (Ne) are typically smaller than census 
population sizes. Scientists use the Ne concept as the 
number of individuals in a population that would result in the same 
loss of genetic diversity, inbreeding, and genetic drift if they 
behaved in the manner of an idealized population (equal sex ratio, 
random mating, all adults producing offspring, equal numbers of 
offspring per parent, and a constant number of breeding individuals 
across generations) (Frankham 1995, p. 96). The concept of effective 
population size relates to population viability because, as a general 
rule, closed populations with random mating that have effective 
population sizes (1) below 50 are at higher risk of inbreeding 
depression, and (2) below 500 are more likely to lose genetic variation 
important to maintaining long-term evolutionary potential. 
Fragmentation can further exacerbate inbreeding depression and genetic 
loss, while connectivity to larger source populations can alleviate the 
adverse effects of small effective population sizes (Frankham et al. 
2014, p. 60). In addition, small, isolated populations are more 
vulnerable to extinction through interactions between environmental, 
genetic, and demographic factors (Caughley 1994, pp. 221-227).
    The only available estimate of effective population size in 
wolverines in the contiguous United States is from the Northern Rocky 
Mountains (inclusive of the Greater Yellowstone Ecosystem, Idaho, and 
Montana). This is where the bulk of the wolverine population in the 
contiguous United States resides (Service 2023, table 4). In 2009, the 
Ne estimate for the Northern Rocky Mountains was 35 
(credible interval = 28-52), and Ne did not change 
significantly from 1989-2006 (Schwartz et al. 2009, p. 3226). There are 
no published estimates of effective population size for wolverines in 
the North Cascades. Therefore, we estimated the effective population 
size of wolverines in the North Cascades, and the result was an 
estimate of Ne = 4 for the North Cascades (Service 2023, p. 
27).
    Overall, the effective population size estimates of wolverines 
occurring in the contiguous United States are small compared to 
conservation guidelines. Therefore, wolverines in the contiguous United 
States appear to be vulnerable to inbreeding and loss of genetic 
diversity when considered in isolation. However, only one or two 
migrants per generation are likely needed to achieve genetic population 
connectivity (Cegelski et al. 2006, p. 13). If populations were 
connected with a sufficient level of gene flow to offset the random 
loss of genetic variation in small populations, it would be more 
appropriate to evaluate the effective population size of the 
transboundary, interconnected population for the purposes of using 
conservation genetic rules-of-thumb.
Gene Flow Between the United States and Canada
    In the contiguous United States, small, isolated wolverine 
populations are likely dependent on gene flow from Canada for 
population persistence (Cegelski et al. 2006, pp. 208-209; McKelvey et 
al. 2014, entire). Based on simulation analyses of gene loss, a census 
population of approximately 2,400 adult wolverines in the Northern 
Rocky Mountains and Greater Yellowstone Ecosystem would be needed to 
maintain 95 percent of the genetic variation over 100 wolverine 
generations (Cegelski et al. 2006, pp. 12-13). Because there is not 
likely sufficient habitat for that number of wolverines in the entire 
contiguous United States (Inman et al. 2013, p. 282), gene flow on the 
order of one or two wolverines per generation from Canada is critical 
to maintaining genetic diversity in wolverines in the contiguous United 
States (Cegelski et al. 2006, p. 13).
    The best available genetic data indicate genetic structuring of 
populations despite some dispersal in the Northern Rocky Mountains 
(Cegelski et al. 2006, pp. 204-205, 208; Sawaya et al. 2023, pp. 12-
14), indicating reduced gene flow. Nuclear genetic diversity was lower 
in the southern periphery of the subspecies' range where the recent 
recolonization from Canada occurred (Sawaya et al. 2023, pp. 9-11). 
Differences in allele frequencies between the United States and Canada 
along the Rocky Mountains are observed, with some areas of overlap in 
wolverine populations straddling the border due to male-mediated gene 
flow. Females appear to be segregated near the international border due 
to their higher rates of philopatry than males, and their apparently 
greater tendencies to avoid crossing major roadways, including major 
highways (Highway 1 and 3) in southern British Columbia (Sawaya et al. 
2023, p. 12, 17). Traffic volumes have substantially increased since 
these highways were opened in the 1960s (British Columbia Ministry of 
Transportation and Highways 2001, pp. 7-11, 16-21).
    No unique contemporary maternal lineages have been detected south 
of the international border, which is consistent with wolverines 
recolonizing the contiguous United States from Canada within the last 
60-70 years (Sawaya et al. 2023, pp. 2, 16-17). Substantially lower 
mitochondrial DNA diversity in the United States, compared to Canada, 
is consistent with limited contemporary female gene flow between the 
countries along the Northern Rocky Mountain range and the North 
American wolverine's relatively recent recolonization at the southern 
edge of their range (Sawaya et al. 2023, p. 17).
    Wolverines in western Washington and southern British Columbia form 
a small transboundary population in the North Cascades (Aubry et al. 
2023, p. 4). Wolverines in the North Cascades are isolated from other 
wolverine populations in the United States and Canada and likely went 
through a genetic bottleneck with few founders (Sawaya 2023, pers. 
comm.). The population has low heterozygosity (less than 0.5) and is 
likely experiencing some level of inbreeding (Sawaya 2023, pers. 
comm.). However, there are currently no indications of inbreeding 
depression (Sawaya 2023, pers. comm.).
Population Structure and Gene Flow Within Canada
    In our 2018 SSA, we stated that wolverines in Canada are considered 
to occur as a single large group because they are easily able to move 
between areas of good habitat and because wolverine habitat is 
relatively contiguous. New scientific information now shows that 
certain anthropogenic

[[Page 83758]]

features (e.g., multi-lane highways) limit gene flow in southwestern 
Canada and supports previous research showing a pattern of decreasing 
genetic diversity in wolverines from north to south (e.g., Sawaya et 
al. 2019, pp. 621-623; Sawaya 2023, pers. comm.). Human infrastructure 
and other anthropogenic and natural barriers also have the potential to 
impede dispersal and affect wolverine population distribution and gene 
flow in Canada (Lofroth and Ott 2007, pp. 2194-2195). These impediments 
are more prevalent in the southern portions of Canada (e.g., Lofroth 
and Ott 2007, p. 2194). Additionally, the best available genetic data 
indicate substantial female population genetic isolation in wolverines 
(McKelvey et al. 2014, pp. 328-332; Schwartz et al. 2009, appendix A; 
Zigouris et al. 2012, pp. 1520-1522; Sawaya et al. 2023, p. 17), with 
the possibility that the Trans-Canada Highway represents a 
``continental barrier to female wolverine movement'' (Sawaya et al. 
2019, p. 623). There is also new information that Highway 3 in southern 
British Columbia likely limits female wolverine gene flow (Sawaya et 
al. 2023, pp. 17). Therefore, wolverine populations in southern British 
Columbia and Alberta near the transboundary interface are less 
genetically connected to the contiguous United States than we found in 
our 2018 SSA.
Gene Flow Within the Contiguous United States
    Previous studies found wolverines have a strong association with 
areas that have persistent spring snow cover (Copeland et al. 2010, 
entire). Snow depth was the most important variable for predicting 
genetic structure overall in a new landscape genetics study in the 
Northern Rockies and at smaller spatial scales (up to about 230 km 
between genetic samples); however, at broad spatial scales (more than 
430 km between genetic samples), housing density and terrain ruggedness 
explained the most variability in wolverine population genetic 
structure (Balkenhol et al. 2020, p. 799). These data highlight the 
importance of maintaining dispersal corridors for wolverines outside of 
core habitats, as they represent critical pathways for gene flow across 
broad spatial scales (Balkenhol et al. 2020, p. 799).
    Analyses of the mitochondrial DNA revealed regional structuring 
(i.e., regional grouping), with all of the samples collected in Idaho, 
Montana, and Wyoming assigned to Haplotype Wilson A (the most abundant 
haplotype in North America) and all of the samples in Washington 
assigned to Haplotype Wilson C (Lukas et al. 2020, p. 846). Haplotypes 
are groups of genes within an organism that are inherited together from 
a single parent. These results are consistent with the latest 
transboundary genetic analysis (Sawaya et al. 2023, entire) and 
previous mitochondrial DNA studies showing that the Northern Rocky 
Mountains and North Cascades do not appear to share any contemporary 
haplotypes (McKelvey et al. 2014, p. 328). New information also 
suggests that wolverines in the Greater Yellowstone Ecosystem have 
relatively low genetic diversity and high genetic distance from other 
wolverine populations in Idaho and Montana (Sawaya et al. 2023, pp. 8-
9, 15-16).
    The low effective population size and low genetic diversity present 
is likely the result of the recent colonization of the contiguous 
United States by wolverines from Canada. Relatively few migrants per 
generation would be needed to maintain the genetic health of wolverines 
in the contiguous United States. New genetic information indicates that 
gene flow across the landscape has been impeded by various barriers to 
wolverine (particularly female) movement. There is currently no 
evidence of inbreeding depression or any deleterious genetic effects in 
the contiguous U.S. population. Based on the best available scientific 
and commercial information, the low genetic diversity present in the 
contiguous United States is not currently a threat to the contiguous 
U.S. DPS of North American wolverine at the population level. However, 
in combination with other threats that limit dispersal of wolverines 
(roads, infrastructure development, climate change, trapping in 
Canada), the gene flow from Canada that is critical to maintaining 
genetic diversity in wolverines in the contiguous United States could 
be compromised and lead to future deleterious genetic effects to the 
contiguous U.S. DPS of North American wolverine.
    Small Population Effects: The number of North American 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 habitat and previous persecution and unregulated trapping 
pressures. In our 2018 finding and October 13, 2020, withdrawal 
document (85 FR 64618), we considered wolverines in the contiguous 
United States to be genetically connected to wolverines in Canada, and 
that wolverines in the contiguous United States were not separated from 
the larger North American wolverine population to the North (Canada and 
Alaska). We concluded that small population effects are not a stressor 
for wolverines in the contiguous United States now or within the 
foreseeable future.
    Wolverine populations in the contiguous United States are small, 
fragmented, and relatively isolated from larger populations in Canada 
(Sawaya 2023, pers. comm.). Although male-mediated dispersal shows some 
level of wolverine population connectivity between the United States 
and Canada along the Rocky Mountains, female wolverines appear to have 
virtually no recent population connectivity based on genetic analyses 
(Sawaya 2023, pers. comm.). Small, isolated populations are more 
vulnerable to extinction through interactions of environmental, 
genetic, and demographic factors (Caughley 1994, pp. 221-227). 
Stochasticity in demographic rates at small population sizes causes 
outsized impacts to vital rates, even in a constant environment, which 
can greatly increase extinction risk. The repopulation of wolverines in 
the contiguous United States from Canada post-unregulated trapping over 
the last approximately 100 years 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. 
However, the resiliency of the contiguous U.S. population to future 
catastrophic events is predicated on the ability of dispersing 
wolverines from Canada to repopulate the contiguous United States. As 
discussed above, connectivity with Canada is more limited than 
previously thought, especially considering the lack of female 
dispersal, which would be necessary for continued repopulation. Based 
on the best available scientific and commercial information, the small 
population size present in the contiguous United States is not 
currently a threat to wolverines at the population level. However, in 
combination with other threats, the small population size of wolverines 
in the contiguous United States could lead to a reduced ability of the 
population to withstand catastrophic events in the future.

Conservation Efforts and Regulatory Mechanisms

Federal Regulatory Mechanisms
    Management of the wolverine and its habitat on Federal lands is 
crucial to

[[Page 83759]]

wolverine conservation, as Federal lands make up approximately 96 
percent of modeled wolverine habitat, the majority of which are U.S. 
Forest Service lands (Service 2018, p. 103). The U.S. Forest Service 
manages the National Forest System lands in accordance with local land 
and resource management plans (Forest Plans). In 2012, the U.S. Forest 
Service published rules for revising Forest Plans (see 77 FR 21162, 
April 9, 2012, and 36 CFR part 219). The 2012 planning rule adopts a 
complementary ecosystem (coarse filter) and species-specific (fine 
filter) approach to maintaining the diversity of plant and animal 
communities and the persistence of native species in the plan area, 
within U.S. Forest Service authority and consistent with the inherent 
capability of the plan area (36 CFR 219.9). This complementary approach 
includes ecosystem and species-specific plan components.
    In our 2018 SSA, we identified Forest Plans as important ``federal 
mechanisms'' that, in combination with State wildlife action plans, 
``will alleviate effects associated with potential impacts related to 
stressors discussed in this report.'' However, in our 2018 SSA, we 
reviewed only four Forest Plans and did not identify in those plans any 
specific standards (mandatory constraints on project and activity 
decision-making) for wolverines.
    For the wolverine SSA report addendum, we conducted a more 
comprehensive review of the latest Forest Plans for 20 National Forests 
within the current breeding range of the contiguous U.S. DPS of North 
American wolverine. We found a complex array of plan components aimed 
at achieving the 2012 planning rule's complementary ecosystem and 
species-specific approach, while balancing the U.S. Forest Service's 
multiple-use mandate. Some plans provided wolverine-specific 
guidelines, objectives, and direction to minimize effects of roads, 
winter recreation, and other sources of human disturbance, but we did 
not identify any wolverine-specific standards. The focus of wolverine-
specific plan components, when they were included, was most often 
limited to protection of known den sites and maternal habitat during 
the denning season.
    Course-filter protections of habitat-types and ecosystems contained 
in the plans will undoubtably provide some conservation benefits to 
wolverines. For example, generally wolverines will benefit from 
wilderness area protections (calculated as 18 percent of the extent of 
wolverine occurrence and 41 percent of core wolverine habitats in the 
western United States (Service 2018, p. 103)); limitations on 
development and road construction; limitations on road densities in 
certain areas for the grizzly bear (Ursus arctos horribilis) or other 
species; and restrictions on over-snow travel. However, quantifying 
these benefits outside of wilderness areas is challenging given the 
variability in Forest Plan standards and conservation measures across 
the U.S. range of the wolverine.
    U.S. Forest Service regulations require National Forests to 
designate roads, trails, and off-road areas that are open and closed to 
motor vehicle use (36 CFR 212.5). In 2015, the U.S. Forest Service 
published a final rule indicating that it will also designate roads, 
trails, and areas open or closed to over-snow motor vehicle use (80 FR 
4500; January 28, 2015). These designations are done on a Forest-by-
Forest basis, resulting in variability in the amount of wolverine 
habitat impacted by these designations. For example, a recent draft 
environmental assessment for the Idaho Panhandle National Forests 
proposed to increase the area available to motorized over-snow use, 
resulting in projected increased impacts to primary wolverine habitat 
(from 39 percent currently to 52 percent under the proposed action) and 
maternal denning habitat (from 44 percent currently to 52 percent under 
the proposed action) (U.S. Forest Service 2023, p. 67). Conversely, the 
Gallatin National Forest reduced the amount of area open to over-snow 
use from 42 percent of wolverine denning habitat on the Forest to 25 
percent (U.S. Forest Service 2006, chapter 3-623). This variability, 
and the lack of a rangewide assessment that overlays the areas of U.S. 
Forest Service over-snow vehicle use closures and wolverine habitat, 
make it difficult to characterize the effects of over-snow travel 
management planning on wolverines in the contiguous United States.
    Several large National Parks contain core habitat for wolverines, 
including Yellowstone, Grand Teton, Glacier, North Cascades, and Mount 
Rainer National Parks. These areas are largely protected from 
development, although they may be impacted by winter recreation to 
varying degrees.
    Although the Bureau of Land Management (BLM) manages relatively 
little land within wolverine core habitats, they do manage some of the 
valley bottoms between these core habitats. The wolverine is listed as 
a special status species by the following BLM offices: Montana/Dakotas 
(revision 2020), Idaho (revision 2022), and Oregon/Washington (revision 
2021). The objectives of the BLM's special-status species policy are: 
(1) to conserve and/or recover species listed under the Act and the 
ecosystems on which they depend so that the protections of the Act are 
no longer needed for these species; and (2) to initiate proactive 
conservation measures that reduce or eliminate threats to BLM sensitive 
species to minimize the likelihood of and need for listing of these 
species under the Act. We did not identify any wolverine-specific 
standards in BLM resource management plans.
State and Provincial Regulatory Mechanisms
    Wolverine trapping remains closed throughout the western United 
States and wolverines have retained various protected status 
designations in these States (Service 2023, table 10). Therefore, legal 
trapping is no longer an active direct stressor on wolverines in the 
contiguous United States. Nevertheless, the legacy effects of recent 
overharvest in southern Canada could negatively affect the wolverine's 
population resilience, distribution, and gene flow in the contiguous 
United States in the future (see Overutilization for Commercial, 
Recreational, Scientific or Educational Purposes, above).
    In response to studies showing that wolverine harvest was 
unsustainable in southeastern British Columbia (Mowat et al. 2020, 
entire), the provincial government closed Resource Management Region 4 
(Kootenay) in the southeastern portion of British Columbia to wolverine 
trapping and imposed a more intensive mortality recording system in 
that region in the fall of 2020 (British Columbia 2022, p. 76). Regions 
2 (Lower Mainland) and 8 (Okanagan) remain closed to wolverine trapping 
under a temporary moratorium; therefore, the entire area of British 
Columbia along the U.S.-Canada border is now closed to wolverine 
trapping (British Columbia 2022, p. 76). Wolverine trapping remains 
open seasonally in British Columbia Resource Management Units 3, 5, 7A, 
7B, and portions of Unit 6 (British Columbia 2022, p. 76), as well as 
in the Rocky Mountain region of southwestern Alberta (Alberta 
Environment and Parks 2022, pp. 14-15).
    Resource management units in southern British Columbia remain open 
to trapping for several other furbearers, and incidental trapping of 
two wolverines has been documented following the closure in the 
Kootenay Resource Management Unit to wolverine trapping (Vander Vennen 
2020, in litt.). Given the likelihood that there is some noncompliance 
with reporting incidental captures, the

[[Page 83760]]

precise number of wolverines incidentally trapped in Canada is not 
known (Vander Vennen 2022, in litt.). We note here that we have no 
indication that noncompliance with reporting incidental captures is a 
concern in the contiguous United States. There are many State 
regulations and guidelines in place to limit incidental wolverine 
trapping, and we have gathered the most up-to-date information on 
incidental captures from States within the range for inclusion in this 
rule (see Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes, above).
    Aside from regulated taking of wolverines, regulatory mechanisms 
available to States for conserving wolverines are largely related to 
maintaining habitat conditions that support wolverine connectivity. 
This is because the majority of the primary habitat cores for 
wolverines in the contiguous United States are on lands managed by the 
U.S. Forest Service. We are not aware of any other State regulatory 
mechanisms specific to wolverines that limit development, winter 
recreation, or other human disturbances in areas important to wolverine 
connectivity in the contiguous United States. Several States and other 
organizations, however, are implementing a number of voluntary 
monitoring or conservation measures for wolverines (see below).
Voluntary Conservation Measures
    Western States continue to invest in monitoring wolverine 
occupancy. A notable effort includes that of the Western Association of 
Fish and Wildlife Agencies (WAFWA) Western States Wolverine Working 
Group, now referred to as the Forest Carnivore Sub-Committee. The 
purpose of this subcommittee is to develop a ``statistically 
defensible'' multi-State monitoring plan for States where wolverine 
populations exist (Wyoming, Montana, Idaho, and Washington), to seek 
funding to implement the monitoring plan, to coordinate development of 
individual State wolverine conservation plans for States with suitable 
wolverine habitat, and to coordinate and prioritize research efforts 
(WAFWA 2022, p. 1).
    In 2020, the Wyoming Game and Fish Department (WGFD) developed a 
wolverine management plan for the State of Wyoming that includes 
management and conservation strategies in Wyoming. Its goals are to: 
(1) promote long-term wolverine viability, (2) support expansion of 
wolverines into suitable habitat, (3) support multi-State monitoring 
efforts, and (4) support management of the wolverine as a protected 
animal (WGFD 2020, p. 2).
    Since 2018, Montana Fish, Wildlife and Parks has completed 10 
habitat conservation projects in wolverine habitat that conserve 59,725 
acres through fee title acquisition or perpetual conservation easement. 
A spatial toolset is now available for western Montana to help 
prioritize these types of acquisitions and easements (Carroll et al. 
2021b, entire). Other tools such as the Crucial Areas Planning System 
(CAPS), a web-based landscape-scale planning tool, have also been put 
in place to help guide future developments that can impact wolverine 
habitat (MFWP 2022, in litt., p. 6).
    In January 2023, the Idaho Fish and Game Commission (IFGC) adopted 
a revised management plan for the conservation of fisher (Pekania 
pennanti), wolverine, and Canada lynx. This plan provides updated 
guidance and identifies management priorities for the conservation of 
this suite of species over the next 6 years in Idaho. These priorities 
include four objectives and step-down actions related to connectivity, 
climate, incidental trapping, and increasing our knowledge of the 
relationship of wolverine denning and snow. Under the objective of 
addressing connectivity, IFGC proposes to continue contributing to the 
transboundary landscape genetics study, to develop products to support 
project planning and review, to develop voluntary partnerships to 
facilitate protections of important areas for movement and dispersal, 
to provide technical assistance to licensing and permitting 
authorities, and to maintain and to conserve wolverine populations and 
habitats through cooperative agreements. For the climate change 
objective, IFGC intends to improve modeling and monitoring. For the 
incidental trapping objective, IFGC intends to continue providing 
guidance and mandatory training to minimize nontarget capture of 
wolverines in traps. Lastly, to fill knowledge gaps, IFGC proposes to 
identify denning sites and will, if feasible, develop a model to 
predict denning areas to inform land management planning efforts.
    The Utah Wildlife Migration Initiative, founded in 2017, identifies 
and protects connective corridors that allow fish and wildlife to 
migrate to necessary habitat areas around the State. The mission is to 
document, preserve, and enhance wildlife movement for species 
throughout Utah using state-of-the-art tracking and data management 
technologies, strong collaborative partnerships, and compelling 
outreach. The Migration Initiative and its partners are mapping the 
movements of wildlife, including wolverines, so crossing structures can 
be placed in areas that coincide with movement corridors. Similar work 
is being conducted in other States and is coordinated between States.
    Colorado Parks and Wildlife had previously considered reintroducing 
wolverines to Colorado as a nonessential experimental population to 
further their conservation (see 78 FR 7890; February 4, 2013). However, 
that proposal was withdrawn in 2014, when we withdrew our proposed 
listing rule (see 79 FR 47522; August 13, 2014). There is currently no 
formal proposal to reintroduce wolverines to Colorado.
    Since 2019, Woodland Park Zoo has been coordinating the Washington 
Wolverine Research and Monitoring Group, a coalition of researchers and 
conservationists who lead wolverine projects in Washington (Woodland 
Park Zoo 2022, in litt.). The goal of this group is to help advance 
North American wolverine research and monitoring in Washington by 
strengthening communication and collaboration among wolverine projects 
Statewide. This group meets several times a year to discuss research 
efforts, share results and insights, and strategize around wolverine 
research and conservation in Washington.
Summary of Conservation Efforts and Regulatory Mechanisms
    The various Federal, State, and provincial regulatory mechanisms 
and voluntary conservation efforts described above are expected to 
provide some benefit to North American wolverine conservation in the 
contiguous United States. However, these mechanisms and efforts are 
inadequate to protect the subspecies from the impacts of climate change 
in the future when the cold and snowy conditions this subspecies is 
adapted to are expected to decrease.

Summary of Current Condition

    Currently, in the contiguous United States, North American 
wolverines are distributed in five primary core areas (identified as 
management regions in Inman et al. 2013), including the Northern 
Cascades in Washington; the Salmon-Selway in central Idaho, including 
the Wallowa Mountains of northeastern Oregon; the northern Continental 
Divide in northwest Montana; the Central Linkage region of Idaho and 
Montana; and the Greater Yellowstone Ecosystem (Service 2023, figure 
14). Although long-distance dispersers (primarily males) occasionally 
reach potentially suitable habitat in other regions, known breeding

[[Page 83761]]

populations are currently limited to these core regions.
    The precise size of the wolverine populations in the contiguous 
United States are currently unknown but may be small due in part to 
their large territories and the limited amount of available habitat in 
the contiguous United States. Estimates based on extrapolations of 
densities and suitable habitat suggest there could have been 
approximately 318 wolverines (95 percent CI = 249-926) in the 
contiguous United States more than a decade ago (Inman et al. 2013, p. 
282). The best available estimates of effective population size of 
wolverines in the contiguous U.S. portions of the Northern Rocky 
Mountains and North Cascades are likely fewer than 50 combined 
(Schwartz et al. 2009, p. 3226).
    We 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). Within Idaho, Montana, Washington, and Wyoming, non-
spatial occupancy model estimates were slightly lower in 2021-2022 
(mean occupancy = 0.33; 95 percent CI 0.21-0.34) compared to 2016-2017 
(mean occupancy = 0.27, 95 percent CI 0.27-0.39), but with overlapping 
confidence intervals (Mosby et al. 2023, p. 4; Service 2023, table 2). 
Despite overlapping confidence intervals, Bayesian analysis revealed an 
85 percent chance that the occupancy estimate from 2021-2022 was 
outside the 95 percent CI of the 2016-2017 occupancy estimate (Mosby et 
al. 2023, p. 4). The percentage of surveyed cells that were occupied 
decreased between the sampling periods in Montana (43.7 to 17.0 
percent) and Washington (34.6 to 12.5 percent), increased in Wyoming 
(11.5 to 25.5 percent), and remained relatively unchanged in Idaho 
(33.8 to 34.5 percent) (Service 2023, table 2). Spatial occupancy 
models by geographic area showed substantial differences between the 
sampling periods, with both lower and higher occupancy probabilities 
depending on the geographic area (Service 2023, table 3; Mosby et al. 
2023, pp. 4-7). Although no wolverines were detected during the 2021-
2022 survey in the sampled cells of Oregon, Utah, or Colorado (Service 
2023, table 2), recent wolverine detections from other research efforts 
or incidental observations have been reported in Oregon, Utah, and 
California (Service 2023, p. 6). Despite differences between the 
sampling periods, Mosby et al. (2023, p. 7) indicate that 
interpretations of the relationship between the two estimates be 
considered cautiously, and that repeated surveys into the future will 
be helpful in ultimately interpreting any trends in occupancy 
estimates. The reasons for the observed changes in occupancy by 
geographic region are not yet clear, and could be sampling anomalies, a 
real shift in distribution, or some combination of factors (Mosby et 
al. 2023, p. 7). This aligns with our analysis of wolverine 
observations from State wildlife agencies, the U.S. Forest Service, the 
National Park Service, Tribes, researchers, and others in the western 
United States from 2009-2022, which shows wolverines continue to occupy 
much of the core habitat within their breeding range in the contiguous 
United States (Service 2023, figure 2).
    Contiguous U.S. contemporary wolverine populations are most likely 
descendants of immigrants from Canada (Service 2018, p. 49). Wolverine 
genetic diversity in the contiguous United States is relatively low, 
and there are no known unique mitochondrial DNA haplotypes present in 
contiguous U.S. wolverine populations (Sawaya et al. 2023, pp. 10-11). 
Due to the limited amount of potential wolverine habitat in the United 
States, connectivity and gene flow with Canada is necessary for the 
long-term genetic health and viability of wolverines in the western 
United States. In the North Cascades, new GPS tracking information 
shows that wolverines in western Washington and southern British 
Columbia form a small transboundary population (Aubry et al. 2023, p. 
4), although they are isolated from other wolverine populations in the 
United States and Canada (Sawaya et al. 2023, pp. 9-13, 16). In the 
Northern Rocky Mountains, the best available data indicate genetic 
differences between populations despite some (mostly male-mediated) 
gene flow (Cegelski et al. 2006, pp. 204-205, 208; Sawaya et al. 2023, 
pp. 12, 17). Measurable differences have been reported in mitochondrial 
DNA haplotype diversity and nuclear microsatellite DNA allele 
frequencies between the U.S. Rocky Mountain populations and Canada 
populations (Cegelski et al. 2006, p. 203, Sawaya et al. 2023, pp. 12, 
17). There is currently no evidence of inbreeding depression in 
wolverine populations in the contiguous United States; however, there 
is potential for inbreeding given the relatively small population sizes 
of wolverines here, especially in the Cascades (Sawaya 2023, pers. 
comm.).
    Wolverine populations in much of North America are still recovering 
from large losses of individuals from intensive hunting and unregulated 
predator control in the late 1880s into the mid-20th century (Service 
2018, p. 104). Trapping and poisoning from the late 1800s/early 1900s 
contributed to extirpation in the contiguous United States during that 
time, but individuals have come back (from Canada) over the years 
since. Trapping or hunting of wolverines remains prohibited in the 
United States, and mortality from incidental trapping is currently 
rare. Over the past century, there has been enough connectivity with 
Canada for wolverines to repopulate the contiguous United States. New 
genetic research provides further evidence of this recolonization via 
dispersers from Canada (Service 2023, pp. 27-28). However, connectivity 
in recent years is less certain.
    In our October 13, 2020, withdrawal document (85 FR 64618), we 
determined that wolverines in the contiguous United States were 
connected to and an extension of the Canadian population. We now know 
that there are potential barriers to recent movement of wolverines to 
and from the contiguous United States, as evidenced by the genetic 
profile of wolverines in the contiguous United States (Sawaya et al. 
2023, entire). Trapping in Canada near the international border was 
thought to be occurring at sustainable levels at the time we published 
our October 13, 2020, withdrawal document (85 FR 64618). In a portion 
of southwestern Canada encompassing a Rocky Mountain National Park 
complex and surrounding unprotected lands, the wolverine population 
declined approximately 40 percent (approximately 15-20 wolverines) from 
2011-2020, likely due largely to overharvest through trapping (Barrueto 
et al. 2022, p. 4). This area may be an important source of dispersing 
individuals, and overharvest could reduce pressure for surplus 
wolverines, particularly females, to disperse south towards the 
contiguous United States. In addition, genetic analysis shows that 
recent dispersing individuals from Canada have been exclusively male 
wolverines and major highways in Southern Canada appear to limit female 
dispersal (Sawaya et al. 2023, pp. 12-14, 17). Also, various studies 
that have come available since the 2018 SSA report reinforce the 
understanding that wolverines avoid areas of significant human 
development and that development may inhibit dispersal of wolverines 
between home ranges and

[[Page 83762]]

habitat patches (Service 2023, pp. 34-36). Even though there is low 
genetic diversity in the contiguous U.S. population, the population is 
relatively small, and habitat is somewhat fragmented, there is no 
current evidence of inbreeding depression in contiguous U.S. wolverines 
and the population appears stable from an occupancy perspective.
    We evaluated several threats that may be affecting wolverine 
populations or their habitats, including effects from roads, 
disturbance due to winter recreational activities, human disturbance 
and development, effects from wildland fire, disease and predation, 
overutilization, genetic diversity, small population effects, and 
climate change. Although these threats may affect individual 
wolverines, none of these threats is currently impacting wolverine 
resiliency (the subspecies' ability to rebound from environmental 
stochasticity) in the contiguous United States at a population level. 
In the future, the synergistic effect of some of these threats coupled 
with the impact of climate change (increased temperatures and decreased 
spring snowpack) could reduce resiliency of the contiguous U.S. 
population (see Summary of Future Condition, below), although climate 
change is not currently impacting the DPS. Currently, the contiguous 
U.S. population appears resilient because despite the potential threats 
analyzed, the population continues to show stability and wolverines 
occupy a large portion of the available habitat in the western United 
States, providing redundancy to withstand potential catastrophes. 
Wolverine breeding populations in the western United States are 
currently distributed across four unique ecoregions (Service 2023, 
figure 16). This ecoregion variation can correlate with species-wide 
evolutionary potential, providing representation (the ability to adapt 
to changes in the biological and physical environment). The North 
American wolverine's wide distribution across multiple ecoregions and 
differential exposure to various stressors also affords the DPS 
redundancy against catastrophic events. Overall, the current 
resiliency, redundancy, and representation of the contiguous U.S. 
population of wolverines supports current DPS viability.

Summary of Future Condition

    In the wolverine SSA report addendum, we provide a comprehensive 
analysis of the future condition of wolverines in the contiguous United 
States, which we summarize here (Service 2023, pp. 61-69). Wolverine 
habitat in the contiguous United States is projected to decrease and 
become more fragmented by the end of the century as a result of climate 
changes that result in increasing temperatures, earlier spring 
snowmelt, and loss of deep, persistent spring snowpack, primarily at 
lower elevations (see Climate Change, above). Winter recreation, which 
has been shown to negatively influence wolverine behavior during an 
important time of year when females are denning and raising young, in 
these diminished habitats may increase as human populations increase 
(U.S. Forest Service 2016, pp. 12-14). In addition, snow-dependent 
recreation that was formerly distributed over a wider elevation 
gradient will be constrained to that part of the gradient that contains 
quality snow into the future. Concurrently, human development may 
continue to expand in areas between core habitats that are important 
for maintaining wolverine population connectivity. While wolverines are 
capable of crossing areas with some human disturbance during dispersal, 
they also have shown some sensitivity to human development and other 
human impacts in rugged areas located between typical core wolverine 
habitats (Balkenhol et al. 2020, p. 799; Barrueto et al. 2022, p. 4). 
Increased human development, infrastructure, and associated 
anthropogenic disturbance are expected to have direct and indirect 
effects to wolverine populations in the contiguous United States, 
including reducing the number of wolverines that can be supported by 
available habitat, reducing the ability of wolverines to travel between 
patches of suitable habitat, and reducing potential dispersers from 
Canada. A reduction in population size and connectivity within the 
contiguous United States and with Canada may affect metapopulation 
dynamics, making it more difficult for subpopulations to recolonize 
currently extirpated areas and augment the genetics or demographics of 
adjacent subpopulations. We expect wolverine resiliency and redundancy 
in the contiguous United States to decline in the future.
    We have identified significant uncertainties that hamper our 
ability to predict the scope, scale, and timing of future demographic 
outcomes for wolverines in the contiguous United States. These include 
uncertainties in mechanistic habitat relationships; census and 
effective population sizes; and the cumulative impact of multiple 
stressors on population connectivity, survival, and reproduction. 
Nevertheless, habitat loss through climate change, combined with other 
stressors, is likely to negatively impact wolverines in the contiguous 
United States over the next century by reducing resiliency, redundancy, 
and representation. Moreover, there are few actions that are reasonably 
certain to occur in the future that would compensate for these negative 
impacts.
    We evaluated the contiguous U.S. DPS of North American wolverine's 
ability to respond to environmental change in two ways. First, we 
examined core attributes of the contiguous U.S. DPS of North American 
wolverine's adaptive capacity in relation to standardized attributes to 
characterize the likelihood that wolverines in the western United 
States will be able to adapt to changed conditions (representation) 
(Thurman et al. 2020, entire; Service 2023, figure 15). Second, we 
evaluated the current and potential distribution of wolverines across 
ecological regions of the western United States given that ecological 
changes may vary across space and that wolverines in different 
ecological contexts may have dissimilar responses to these changes.
    The contiguous U.S. DPS of North American wolverine's ability to 
adapt to climate change and other environmental changes, its adaptive 
capacity (representation), is key to reducing its vulnerability to 
these changes. Our qualitative adaptive capacity analysis for the 
contiguous U.S. DPS of North American wolverine was based on life-
history characteristics and shows that several intrinsic factors make 
North American wolverines susceptible to negative outcomes from future 
environmental change (Service 2023, pp. 66-69). Their specialized 
habitat associations, low genetic diversity and population size, narrow 
ecological niche, low tolerance for human disturbance, and slow 
reproductive rate all contribute to the contiguous U.S. DPS of North 
American wolverine's relative difficulty in adapting in-place to future 
environmental change (Service 2023, table 14). Factors that may 
partially mitigate the contiguous U.S. DPS of North American 
wolverine's low adaptive capacity are their ability to disperse long 
distances, their relatively wide distribution in the Northern Rocky 
Mountains and in the North Cascades (albeit in a narrow climactic 
niche), and their flexible diet (Service 2023, table 14). Stressors 
that lessen the ability of North American wolverines to disperse, or 
that decrease their distribution, are likely to also degrade their 
adaptive capacity (redundancy), leaving them more vulnerable to 
environmental change.

[[Page 83763]]

    Maintaining a species, or in this case a subspecies, across its 
full breadth of ecological variation can reduce extinction risk 
(Forester et al. 2022, p. 512). To further assess the contiguous U.S. 
DPS of North American wolverine's future evolutionary potential, we 
examined the DPS's current distribution across different ecoregion 
provinces. Ecoregion provinces incorporate temperature, precipitation, 
and vegetation data, and therefore represent landscapes with similar 
environmental traits (Bailey 2016, entire). Wolverine breeding 
populations in the western United States currently exist in 4 of 10 
ecoregions where there is potential wolverine core habitat (Service 
2023, figure 16). Outside of the area with known wolverine breeding, 
several ecoregions in the western United States contain only a 
relatively small area of potential wolverine core habitat. Except for 
the Sierran Steppe-Forest-Alpine ecoregion, wolverine breeding 
populations currently inhabit all the ecoregions of the western United 
States with large contiguous blocks of potential wolverine core habitat 
(Service 2023, figure 16).
    Despite their relatively wide distribution among ecoregions, 
wolverines in the contiguous United States have low genetic diversity 
compared to Canadian populations and are unlikely to have evolved 
specialized adaptations to southern climates given their recent 
recolonization following extirpation (McKelvey et al. 2014, p. 332). 
The historical population of wolverines in the Sierra Nevada may have 
possessed unique evolutionary potential given the distinct genetic and 
taxonomic characteristics of historical museum samples; however, the 
wolverines in the Sierras were extirpated in the early 1900s, and their 
matrilines were eliminated from North America (McKelvey et al. 2014, p. 
332). Nevertheless, the DPS's distribution across multiple ecoregions 
means that parts of their range may have less exposure to future 
stressors. Expansion into unoccupied ecoregions where there is suitable 
habitat could further decrease their risk of exposure to future 
stressors.
    Wolverine populations in the contiguous United States are currently 
small, fragmented, and relatively isolated from larger populations in 
Canada (Cegelski et al. 2006, pp. 206-207, 210; Sawaya 2023, pers. 
comm.). Although male-mediated dispersal shows some level of wolverine 
population connectivity between the United States and Canada along the 
Rocky Mountains, female wolverines appear to have virtually no recent 
population connectivity based on recent genetic analyses (Sawaya 2023, 
pers. comm.). Small, isolated populations are more vulnerable to 
extinction through interactions between environmental, genetic, and 
demographic factors (Caughley 1994, pp. 221-227). Stochasticity in 
demographic rates at small population sizes causes outsized impacts to 
vital rates, even in a constant environment, which can greatly increase 
extinction risk. Small, isolated populations also lose genetic 
diversity over time, primarily through inbreeding and genetic drift, 
which can exacerbate extinction risk if demographic rates are further 
degraded through inbreeding depression (Benson et al. 2016, p. 8). Low 
genetic diversity can also reduce future adaptive capacity and 
evolutionary potential, reducing representation.
    Although historical wolverine populations were likely naturally 
small and distributed among patches of high-elevation alpine habitats 
in the contiguous United States, core wolverine habitats in the 
contiguous United States are projected to become smaller and more 
fragmented in the future as a result of climate change and human 
disturbance. These changes may degrade the DPS's resiliency and 
redundancy over time, although there are uncertainties in the precise 
amount of degradation, how much this degradation will affect wolverine 
viability in the contiguous United States, or the time period over 
which the degradation would happen. Despite their current distribution 
across several ecological regions of the West, the core attributes 
related to adaptive capacity exhibited by wolverines may limit the 
ability of this DPS to adapt and persist in the face of projected 
environmental change. Long-distance dispersal and recolonization of 
some of the larger areas outside of the current breeding range of the 
contiguous U.S. DPS of North American wolverine (e.g., Sierra Nevada 
and central Rocky Mountains) could partially mitigate their 
susceptibility to environmental change. Dispersal between currently 
occupied core habitats may become more difficult in the future with 
anticipated increases in human development between the alpine core 
areas and increased backcountry winter recreation in core habitats. 
However, wolverine dispersal could be maintained or improved by human 
intervention (e.g., conserving wildlife corridors between alpine 
habitats, constructing highway crossing structures for wildlife).
    Overall, the wolverine population in the contiguous United States 
is expected to decrease in resiliency, redundancy, and representation 
in the future. We acknowledge that new information suggests populations 
in the contiguous United States may be less secure in the future than 
we described in our 2018 SSA and October 13, 2020, withdrawal document 
(85 FR 64618). We also acknowledge that uncertainty remains around gene 
flow between the United States and Canada, core habitats and key 
dispersal corridors among core areas of the contiguous United States, 
and the effective population size in the contiguous United States. 
Nevertheless, the best available information suggests that habitat loss 
as a result of climate change, and the resulting exacerbating effect on 
other stressors, is likely to decrease the viability of wolverines in 
the contiguous United States over the next century.
    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the wolverine SSA report and 
SSA report addendum, we have analyzed the cumulative effects of 
identified threats and conservation actions on the DPS. To assess the 
current and future condition of the DPS, we evaluate the effects of all 
the relevant factors that may be influencing the DPS, including threats 
and conservation efforts. Because the SSA framework considers not just 
the presence of the factors, but to what degree they collectively 
influence risk to the entire DPS, our assessment integrates the 
cumulative effects of the factors and replaces a standalone cumulative 
effects analysis.

Determination of North American Wolverine's 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 an endangered species or a 
threatened species. The Act defines an ``endangered species'' as a 
species in danger of extinction throughout all or a significant portion 
of its range, and a ``threatened species'' as a species 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 83764]]

Status Throughout All of Its Range

    In our 2018 SSA and October 13, 2020, withdrawal document (85 FR 
64618), we noted that during the late 1800s and early 1900s, the 
wolverine population declined or was extirpated in much of the 
contiguous United States. This decline and range contraction has been 
attributed to unregulated trapping and habitat degradation (Hash 1987, 
p. 583). However, given the high-elevation core habitats of wolverines 
in the contiguous United States, direct mortality through predator 
poisoning campaigns and unregulated trapping were likely the primary 
culprits.
    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 
climate change (Factors A and E); 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); and small 
population effects (Factor E). We also assessed the adequacy of 
existing regulatory mechanisms (Factor D).
    After evaluating threats that may be currently affecting wolverines 
in the contiguous United States, we have determined that although these 
threats may affect individual wolverines, there are no threats 
currently impacting wolverines in the contiguous United States at a 
population level. In the future, the synergistic effect of some threats 
coupled with the impacts of climate change (increased temperatures and 
decreased spring snowpack) are expected to reduce resiliency of the 
contiguous U.S. population, although climate change is not currently 
impacting wolverines occurring in the United States. Currently, the 
contiguous U.S. population appears resilient, as wolverines continue to 
consistently occupy a large portion of the available habitat in the 
western United States. Furthermore, wolverine breeding populations in 
the western United States are currently distributed across four 
ecoregions, which affords the DPS redundancy against catastrophic 
events. This ecoregion variation influences representation by 
potentially providing evolutionary potential to adapt to changes in the 
biological and physical environment. Thus, wolverines in the contiguous 
United States are not currently in danger of extinction throughout 
their range.
    We expect wolverine populations in the contiguous United States to 
decrease in resiliency, redundancy, and representation within the 
foreseeable future. We consider 2100 to be the foreseeable future in 
this case. The main threat to wolverines is the effect of climate 
change on spring snow. We were able to reliably model changes in spring 
snow out to 2100 in our climate change analysis, and we are able to 
reasonably determine the wolverine's response to this threat is likely 
in the foreseeable future. Wolverine populations in the contiguous 
United States are small, fragmented, and relatively isolated from 
larger populations in Canada (Cegelski et al. 2006, pp. 206-207, 210; 
Sawaya et al. 2023, entire). Although male-mediated dispersal shows 
some level of wolverine population connectivity between the United 
States and Canada along the Rocky Mountains, female wolverines appear 
to have virtually no recent population connectivity based on recent 
genetic analyses (Sawaya et al. 2023, pp. 12-14, 17). Small, isolated 
populations are more vulnerable to extinction through interactions 
between environmental, genetic, and demographic factors (Caughley 1994, 
pp. 221-227). Stochasticity in demographic rates at small population 
sizes causes outsized impacts to vital rates, even in a constant 
environment, which can greatly increase extinction risk. Small, 
isolated populations also lose genetic diversity over time, primarily 
through inbreeding and genetic drift, which can exacerbate extinction 
risk if demographic rates are further degraded through inbreeding 
depression (Benson et al. 2016, p. 8). Low genetic diversity can also 
reduce adaptive capacity and evolutionary potential.
    Although historical North American wolverine populations were 
likely naturally small and distributed among patches of high-elevation 
alpine habitats in the contiguous United States, core wolverine 
habitats in the United States are projected to become smaller and more 
fragmented in the future as the result of climate change and human 
disturbance. These changes are expected to degrade wolverine resiliency 
and redundancy over time, although there are uncertainties in the 
precise amount of degradation, how much this degradation will affect 
wolverine viability in the contiguous United States, and the precise 
time period over which the degradation would happen. Despite these 
uncertainties, the best available information indicates the impacts are 
such that the DPS's viability will decrease within the foreseeable 
future. Although wolverines are currently distributed across several 
ecological regions of the U.S. West, the core attributes related to 
their adaptive capacity may limit the ability of this DPS to adapt and 
persist in the face of projected environmental change. Long-distance 
dispersal and recolonization of some of the larger areas outside of the 
current breeding range of North American wolverines (e.g., Sierra 
Nevada and central Rocky Mountains) could partially mitigate their 
susceptibility to environmental change. However, natural dispersal 
between currently occupied core habitats is expected to become more 
difficult in the future with anticipated increases in human development 
between the alpine core areas and increased backcountry winter 
recreation in core habitats.
    After evaluating threats to the DPS and assessing the cumulative 
effect of the threats under the Act's section 4(a)(1) factors, we find 
that wolverine populations in the contiguous United States are less 
secure in the future than we described in our 2018 SSA and October 13, 
2020, withdrawal document (85 FR 64618). The best available information 
suggests that habitat loss as a result of climate change and impacts 
from other stressors are likely to negatively impact the viability of 
wolverines in the contiguous United States over the next century. Thus, 
after assessing the best available information, we conclude that the 
contiguous U.S. DPS of North American wolverine in is not currently in 
danger of extinction but is likely to become in danger of extinction 
within the foreseeable future throughout all of its range.

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 
within the foreseeable future throughout all or a significant portion 
of its range. The court in Center for Biological Diversity v. Everson, 
435 F. Supp. 3d 69 (D.D.C. 2020) (Everson), vacated the provision of 
the Final Policy on Interpretation of the Phrase ``Significant Portion 
of Its Range'' in the Endangered Species Act's Definitions of 
``Endangered Species'' and ``Threatened Species'' (Final Policy; 79 FR 
37578; July 1, 2014) that provided if the Service determines that a 
species is threatened throughout all of its range, the Service will not 
analyze whether the species is endangered in a significant portion of 
its range.
    Therefore, we proceed to evaluating whether the species is 
endangered in a

[[Page 83765]]

significant portion of its range--that is, whether there is any portion 
of the species' range for which both (1) the portion is significant; 
and (2) the species is in danger of extinction 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.
    Following the court's holding in Everson, we now consider whether 
there are any significant portions of the North American wolverine's 
range in the contiguous United States where the DPS is in danger of 
extinction now (i.e., endangered). In undertaking this analysis for the 
DPS, we choose to address the status question first--we consider 
information pertaining to the geographic distribution of both the DPS 
and the threats that the DPS faces to identify portions of the range 
where the DPS may be endangered.
    We evaluated the range of the contiguous U.S. DPS of North American 
wolverine to determine if the DPS is in danger of extinction now in any 
portion of its range. The range can theoretically be divided into 
portions in an infinite number of ways. We focused our analysis on 
portions of the range that may meet the Act's definition of an 
endangered species. For this DPS, we considered whether the threats or 
their effects on the DPS are greater in any biologically meaningful 
portion of the range than in other portions such that the DPS is in 
danger of extinction now in that portion.
    We examined the following threats: climate change (Factors A and 
E); 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); and small population effects (Factor 
E), including cumulative effects.
    The North Cascades portion of the DPS's range is the only 
biologically meaningful portion that we identified that could 
potentially have a different status than the remainder of the range. It 
is largely isolated by an expanse of unsuitable habitat from the larger 
Rocky Mountains portion of the range. All of the threats affecting 
wolverines are ubiquitous throughout the contiguous U.S. range; 
however, the low genetic diversity of the Cascades population could 
potentially affect this portion more so than the rest of the range due 
to the apparent lack of recent genetic connectivity with Canada in that 
portion (Sawaya 2023, pers. comm.). The North Cascades wolverines are 
isolated from other wolverine populations in the United States and 
Canada and likely went through a genetic bottleneck with few founders 
(Sawaya 2023, pers. comm.). The effective population size of the North 
Cascades population is estimated at Ne = 4, and the 
population may be vulnerable to inbreeding and loss of genetic 
diversity when considered in isolation. Recent genetic research shows 
the population has low heterozygosity (less than 0.5) and may be 
experiencing some level of inbreeding (Sawaya 2023, pers. comm.). 
However, there is currently no indication that individuals or 
population dynamics are being negatively affected by inbreeding 
depression (Sawaya 2023, pers. comm.) or that wolverines in this 
portion are currently being more severely or differently affected by 
any other threats. Gene flow with wolverines in Canada in the future is 
important to the long-term genetic health of the North Cascades 
population, but this portion is not currently in danger of extinction, 
as the population is currently showing stability in occupancy and not 
expressing any deleterious effects of inbreeding.
    We found no biologically meaningful portion of the DPS's range 
where threats are impacting individuals differently from how they are 
affecting the DPS elsewhere in the range, or where the biological 
condition of the DPS differs from its condition elsewhere in the range 
such that the status of the DPS in that portion differs from any other 
portion of the DPS's range.
    Therefore, no portion of the DPS's range provides a basis for 
determining that the DPS is in danger of extinction in a significant 
portion of its range, and we determine that the DPS is likely to become 
in danger of extinction within the foreseeable future throughout all of 
its range. This does not conflict with the courts' holdings in Desert 
Survivors v. U.S. Department of the Interior, 321 F. Supp. 3d 1011, 
1070-74 (N.D. Cal. 2018) and Center for Biological Diversity v. Jewell, 
248 F. Supp. 3d 946, 959 (D. Ariz. 2017) because, in reaching this 
conclusion, we did not apply the aspects of the Final Policy, including 
the definition of ``significant'' that those court decisions held to be 
invalid.

Determination of Status

    Our review of the best scientific and commercial data available 
indicates that the contiguous U.S. DPS of the North American wolverine 
meets the Act's definition of a threatened species. Therefore, we are 
listing that DPS as a threatened species in accordance with sections 
3(20) and 4(a)(1) of the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition as a listed 
species, planning and implementation of recovery actions, requirements 
for Federal protection, and prohibitions against certain practices. 
Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies, private 
organizations, and individuals. The Act encourages cooperation with the 
States and other countries and calls for recovery actions to be carried 
out for listed species. The protection required by Federal agencies, 
including the Service, and the prohibitions against certain activities 
are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Section 4(f) of the Act calls for the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The goal of this process is to restore listed 
species to a point where they are secure, self-sustaining, and 
functioning components of their ecosystems.
    The recovery planning process begins with development of a recovery 
outline made available to the public soon after a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions while a recovery plan is being developed. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) may be 
established to develop and implement recovery plans. The recovery 
planning process involves the identification of actions that are 
necessary to halt and reverse the species' decline by addressing the 
threats to its survival and recovery. The recovery plan identifies 
recovery criteria for review of when a species may be ready for 
reclassification from endangered to threatened (``downlisting'') or 
removal from protected status (``delisting''), and methods for 
monitoring recovery progress. Recovery plans also establish

[[Page 83766]]

a framework for agencies to coordinate their recovery efforts and 
provide estimates of the cost of implementing recovery tasks. Revisions 
of the plan may be done to address continuing or new threats to the 
species, as new substantive information becomes available. The recovery 
outline, draft recovery plan, final recovery plan, and any revisions 
will be available on our website as they are completed (https://www.fws.gov/program/endangered-species), or from our Ecological 
Services Program, Pacific Region (see FOR FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    Once this DPS is listed, funding for recovery actions will be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the 
academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the States of California, Colorado, 
Idaho, Montana, Oregon, Utah, Washington, and Wyoming will be eligible 
for Federal funds to implement management actions that promote the 
protection or recovery of the North American wolverine. Information on 
our grant programs that are available to aid species recovery can be 
found at: https://www.fws.gov/service/financial-assistance.
    Please let us know if you are interested in participating in 
recovery efforts for the contiguous U.S. DPS of the North American 
wolverine. Additionally, we invite you to submit any new information on 
this DPS whenever it becomes available and any information you may have 
for recovery planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7 of the Act is titled, ``Interagency Cooperation,'' and it 
mandates all Federal action agencies to use their existing authorities 
to further the conservation purposes of the Act and to ensure that 
their actions are not likely to jeopardize the continued existence of 
listed species or adversely modify critical habitat. Regulations 
implementing section 7 are codified at 50 CFR part 402.
    Section 7(a)(2) states that each Federal action agency shall, in 
consultation with the Secretary, ensure that any action they authorize, 
fund, or carry out is not likely to jeopardize the continued existence 
of a listed species or result in the destruction or adverse 
modification of designated critical habitat. Each Federal agency shall 
review its action at the earliest possible time to determine whether it 
may affect listed species or critical habitat. If a determination is 
made that the action may affect listed species or critical habitat, 
formal consultation is required (see 50 CFR 402.14(a)), unless the 
Service concurs in writing that the action is not likely to adversely 
affect listed species or critical habitat. At the end of a formal 
consultation, the Service issues a biological opinion, containing its 
determination of whether the Federal action is likely to result in 
jeopardy or adverse modification.
    Examples of discretionary actions for the contiguous U.S. DPS of 
the North American wolverine that may be subject to consultation 
procedures under section 7 are land management or other landscape-
altering activities on Federal lands administered by the U.S. Forest 
Service, National Park Service, and Bureau of Land Management, as well 
as actions on State, Tribal, local, or private lands that require a 
Federal permit (such as a permit from the U.S. Army Corps of Engineers 
under section 404 of the Clean Water Act (33 U.S.C. 1251 et seq.) or a 
permit from the Service under section 10 of the Act) or that involve 
some other Federal action (such as funding from the Federal Highway 
Administration, Federal Aviation Administration, or Federal Emergency 
Management Agency). Federal actions not affecting listed species or 
critical habitat--and actions on State, Tribal, local, or private lands 
that are not federally funded, authorized, or carried out by a Federal 
agency--do not require section 7 consultation. Federal agencies should 
coordinate with the local Service Field Office (see FOR FURTHER 
INFORMATION CONTACT) with any specific questions on section 7 
consultation and conference requirements.
    It is the policy of the Service, as published in the Federal 
Register on July 1, 1994 (59 FR 34272), to identify to the extent known 
at the time a species is listed, specific activities that will not be 
considered likely to result in violation of section 9 of the Act. To 
the extent possible, activities that will be considered likely to 
result in violation will also be identified in as specific a manner as 
possible. The intent of this policy is to increase public awareness of 
the effect of a listing on proposed and ongoing activities within the 
range of the species. Although most of the prohibitions in section 9 of 
the Act apply to endangered species, sections 9(a)(1)(G) and 9(a)(2)(E) 
of the Act prohibit the violation of any regulation, including any 
regulation issued under section 4(d) of the Act, pertaining to any 
threatened species of fish or wildlife, or threatened species of plant, 
respectively. Section 4(d) of the Act directs the Secretary to 
promulgate protective regulations that are necessary and advisable for 
the conservation of threatened species. As a result, we interpret our 
policy to mean that, when we list a species as a threatened species, to 
the extent possible, we identify activities that will or will not be 
considered likely to result in violation of the protective regulations 
under section 4(d) for that species.
    The following activities could potentially result in a violation of 
section 9 of the Act; this list is not comprehensive: Unauthorized 
collecting, handling, possessing, selling, delivering, carrying, or 
transporting of the listed subspecies, including import or export 
across State lines and international boundaries, except for properly 
documented antique specimens of these taxa at least 100 years old, as 
defined by section 10(h)(1) of the Act.
    Questions regarding whether specific activities will constitute 
violation of section 9 of the Act should be directed to the Service's 
Pacific Regional Office (see FOR FURTHER INFORMATION CONTACT).

II. Interim Rule Issued Under Section 4(d) of the Act

Background

    Section 4(d) of the Act contains two sentences. The first sentence 
states that the Secretary shall issue such regulations as she deems 
necessary and advisable to provide for the conservation of species 
listed as threatened species. The U.S. Supreme Court has noted that 
statutory language similar to the language in section 4(d) of the Act 
authorizing the Secretary to take action that she ``deems necessary and 
advisable'' affords a large degree of deference to the agency (see 
Webster v. Doe, 486 U.S. 592, 600 (1988)). Conservation is defined in 
the Act to mean the use of all methods and procedures which are 
necessary to bring any endangered species or threatened species to the 
point at which the measures provided pursuant to the Act

[[Page 83767]]

are no longer necessary. Additionally, the second sentence of section 
4(d) of the Act states that the Secretary may by regulation prohibit 
with respect to any threatened species any act prohibited under section 
9(a)(1), in the case of fish or wildlife, or section 9(a)(2), in the 
case of plants. Thus, the combination of the two sentences of section 
4(d) provides the Secretary with wide latitude of discretion to select 
and promulgate appropriate regulations tailored to the specific 
conservation needs of the threatened species. The second sentence 
grants particularly broad discretion to the Service when adopting one 
or more of the prohibitions under section 9.
    The courts have recognized the extent of the Secretary's discretion 
under this standard to develop rules that are appropriate for the 
conservation of a species. For example, courts have upheld, as a valid 
exercise of agency authority, rules developed under section 4(d) that 
included limited prohibitions against takings (see Alsea Valley 
Alliance v. Lautenbacher, 2007 WL 2344927 (D. Or. 2007); Washington 
Environmental Council v. National Marine Fisheries Service, 2002 WL 
511479 (W.D. Wash. 2002)). Courts have also upheld 4(d) rules that do 
not address all of the threats a species faces (see State of Louisiana 
v. Verity, 853 F.2d 322 (5th Cir. 1988)). As noted in the legislative 
history when the Act was initially enacted, ``once an animal is on the 
threatened list, the Secretary has an almost infinite number of options 
available to [her] with regard to the permitted activities for those 
species. [She] may, for example, permit taking, but not importation of 
such species, or [s]he may choose to forbid both taking and importation 
but allow the transportation of such species'' (H.R. Rep. No. 412, 93rd 
Cong., 1st Sess. 1973).
    The provisions of this 4(d) rule will promote conservation of the 
contiguous U.S. DPS of the North American wolverine by encouraging 
management of the landscape in ways that meet the conservation needs of 
the wolverine. The provisions of this rule are one of many tools that 
we will use to promote the conservation of the DPS.
    As mentioned previously in Available Conservation Measures, section 
7(a)(2) of the Act requires Federal agencies, including the Service, to 
ensure that any action they authorize, fund, or carry out is not likely 
to jeopardize the continued existence of any endangered species or 
threatened species or result in the destruction or adverse modification 
of designated critical habitat of such species.
    These requirements are the same for a threatened species with a 
species-specific 4(d) rule. For example, as with an endangered species, 
if a Federal agency determines that an action is ``not likely to 
adversely affect'' a threatened species that has a species-specific 
4(d) rule, the agency will still need to informally consult with the 
Service and obtain the Service's written concurrence (50 CFR 
402.13(c)). Similarly, if a Federal agency determines that an action is 
``likely to adversely affect'' a threatened species, the action will 
require formal consultation and the formulation of a biological opinion 
(50 CFR 402.14(a)). The Service will take into account the exceptions 
of any 4(d) rule when issuing a biological opinion and any associated 
incidental take statement, but a 4(d) rule does not eliminate the 
Federal agency's obligation to consult under section 7(a)(2) of the 
Act.
    We proposed a 4(d) rule along with our proposed listing rule for 
the contiguous U.S. DPS of the wolverine in 2013 (78 FR 7864; February 
4, 2013). In the proposed 4(d) rule, we stated that we would prohibit 
take of any wolverine in the contiguous United States when associated 
with or related to trapping, hunting, shooting, collection, capturing, 
pursuing, wounding, killing, and trade. We further stated that, in this 
context, any activity where wolverines are attempted to be, or are 
intended to be, trapped, hunted, shot, captured, or collected, in the 
contiguous United States, would be prohibited. Additionally, we said 
that it would also be prohibited to incidentally trap, hunt, shoot, 
capture, pursue, or collect wolverines in the course of otherwise legal 
activities. We also clarified that all otherwise legal activities 
involving wolverines and their habitat that are conducted in accordance 
with applicable State, Federal, Tribal, and local laws and regulations 
would not be considered to be take under the proposed 4(d) rule. We 
identified several risk factors for the U.S. DPS of the wolverine that, 
in concert with climate change, may result in reduced habitat value for 
the DPS. These risk factors included human activities like dispersed 
recreation, land management activities by Federal agencies and private 
landowners, and infrastructure development. However, in 2013, we 
considered these risk factors to be small in scope and scale, and 
ultimately not a concern for the conservation of the DPS. As a result, 
we did not propose to prohibit take associated with these activities.
    New information on the threats to this DPS and how these threats 
may affect the future condition of wolverines in the contiguous United 
States (see Summary of Biological Status and Threats, above) has 
changed our understanding of what provisions are appropriate for the 
contiguous U.S. DPS of the North American wolverine. We are now 
tailoring the provisions of this interim 4(d) rule informed by new 
information. This is an interim rule, meaning that it will go into 
effect on the effective date specified above under DATES, but we are 
also accepting public comments on the 4(d) rule (see DATES and 
ADDRESSES, above). We will assess any comments we receive on the 4(d) 
rule and publish either an affirmation of this interim rule or a 
revised final rule for the 4(d) rule.

Provisions of the Interim 4(d) Rule

    Exercising the Secretary's authority under section 4(d) of the Act, 
we have developed a rule that is designed to address the contiguous 
U.S. DPS of the North American wolverine's conservation needs. As 
discussed previously in Summary of Biological Status and Threats, we 
have concluded that the DPS is likely to become in danger of extinction 
within the foreseeable future primarily due to habitat loss as a result 
of climate change and the cumulative impacts of other, lower-level 
stressors, including winter recreation, development, and major roads. 
Section 4(d) requires the Secretary to issue such regulations as she 
deems necessary and advisable to provide for the conservation of each 
threatened species and authorizes the Secretary to include among those 
protective regulations any of the prohibitions that section 9(a)(1) of 
the Act prescribes for endangered species. We find that the 
protections, prohibitions, and exceptions in this 4(d) rule as a whole 
satisfy the requirement in section 4(d) of the Act to issue regulations 
deemed necessary and advisable to provide for the conservation of the 
DPS.
    The protective regulations for the contiguous U.S. DPS of the North 
American wolverine incorporate prohibitions from section 9(a)(1) to 
address the threats to the DPS. Section 9(a)(1) prohibits the following 
activities for endangered wildlife: importing or exporting; take; 
possession and other acts with unlawfully taken specimens; delivering, 
receiving, carrying, transporting, or shipping in interstate or foreign 
commerce in the course of commercial activity; or selling or offering 
for sale in interstate or foreign commerce. This interim 4(d) rule 
includes all of these prohibitions, with limited exceptions, for the 
DPS. With these general protective prohibitions in

[[Page 83768]]

place, the 4(d) rule reinforces the preservation of the DPS's 
populations by prohibiting activities that would incentivize the 
killing of wolverines for commercial gain.
    As noted, this 4(d) rule generally prohibits the ``take'' of 
wolverines in the DPS. Under the Act, ``take'' means to harass, harm, 
pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to 
attempt to engage in any such conduct. Some of these provisions have 
been further defined in regulation at 50 CFR 17.3. Take can result 
knowingly or otherwise, by direct and indirect impacts, intentionally 
or incidentally. Regulating take will help preserve the DPS's remaining 
populations and decrease the effects to wolverines from the 
synergistic, negative effects from other ongoing or future threats. 
Therefore, we are prohibiting take of wolverines in the DPS, except for 
take resulting from those actions and activities specifically excepted 
by the 4(d) rule.
    Exceptions to the prohibition on take include all of the general 
exceptions to the prohibition on take of endangered wildlife, as set 
forth in 50 CFR 17.21(c) and (d), and additional exceptions, as 
described below.
    The interim 4(d) rule also provides for the conservation of the DPS 
by establishing exceptions to the general prohibition against ``take'' 
of wolverines in the DPS in support of conservation actions and 
otherwise lawful activities that could incidentally take a wolverine 
but at minimal levels not likely to have a negative impact on the DPS's 
conservation. We considered a variety of exceptions and determined that 
not all were necessary (e.g., we do not include an exception for take 
of depredating wolverines because wolverines rarely take livestock) or 
would provide conservation benefits (e.g., we do not include exceptions 
for backcountry winter recreation because recreating in these areas can 
be detrimental to wolverines). The exceptions to these prohibitions, 
described in further detail below, include certain standard exceptions, 
as well as purposeful take due to scientific research on wolverines, 
take incidental to forest management activities for the purposes of 
reducing the risk or severity of wildfire, and take incidental to legal 
trapping of species other than the wolverine that is conducted 
consistent with State trapping laws and regulations and that contains 
steps to minimize the potential for capture of wolverines.
    Nothing in this interim 4(d) rule will change in any way the 
recovery planning provisions of section 4(f) of the Act, the 
consultation requirements under section 7 of the Act, or the ability of 
the Service to enter into partnerships for the management and 
protection of the wolverine. However, interagency cooperation may be 
further streamlined through planned programmatic consultations for the 
species between Federal agencies and the Service.

Standard Exceptions

    We may, under certain circumstances, issue permits to carry out one 
or more of the otherwise prohibited activities. These include permits 
issued for the following purposes: for scientific research and 
conservation purposes (for an activity that would not fall within the 
research exception for incidental take in the 4(d) rule, as described 
below); to enhance propagation or survival; for economic hardship; for 
zoological exhibition; for educational purposes; for incidental taking 
(for an activity not already excepted in the 4(d) rule); or for special 
purposes consistent with the purposes of the Act (see 50 CFR 17.32). 
The Act also contains certain exemptions from the prohibitions, which 
are found in sections 9 and 10 of the Act.
    We recognize the special and unique relationship with our State 
natural resource agency partners in contributing to conservation of 
listed species. State agencies often possess scientific data and 
valuable expertise on the status and distribution of endangered, 
threatened, and candidate species of wildlife and plants. State 
agencies, because of their authorities and their close working 
relationships with local governments and landowners, are in a unique 
position to assist us in implementing all aspects of the Act. In this 
regard, section 6 of the Act provides that we cooperate to the maximum 
extent practicable with the States in carrying out programs authorized 
by the Act. Therefore, any qualified employee or agent of a State 
conservation agency that is a party to a cooperative agreement with us 
in accordance with section 6(c) of the Act, who is designated by his or 
her agency for such purposes, will be able to conduct activities 
designed to conserve the contiguous U.S. DPS of the North American 
wolverine that may result in otherwise prohibited take without 
additional authorization.

Scientific Research

    Future scientific research on North American wolverines in the 
contiguous United States will aid conservation and recovery by leading 
to a better understanding of the biology and ecology of this elusive 
and hard-to-study species. 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 
(Service 2018, p. 52). 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 (Service 2018, p. 52). Activities 
associated with scientific research may include capture, anesthesia, 
collaring, tracking, genetic sampling, the use and baiting of camera 
and DNA traps, den monitoring, and aerial surveying. State agencies 
with approved cooperative agreements (see cooperative agreements 
discussion above for additional information) and the Service will not 
be required to obtain separate ESA permits for take associated with 
these actions, as we are including the exceptions at 50 CFR 17.31(b) in 
the 4(d) rule. To facilitate Federal agencies or federally recognized 
Tribes to participate in and assist with these activities, we are also 
including an exception that allows biologists, acting in an official 
capacity, from other Federal agencies or federally recognized Tribes to 
take wolverine for scientific or research purposes that are associated 
with wolverine conservation efforts, as identified by the Service, 
provided such taking does not result in death or permanent injury to 
the wolverine(s) involved. Taking that results in death or permanent 
injury must be reported to the appropriate U.S. Fish and Wildlife 
Service law enforcement office and to appropriate State and Tribal 
authorities.

Forest Management Activities for the Purposes of Reducing the Risk or 
Severity of Wildfire

    As discussed in the February 4, 2013, proposed listing rule (78 FR 
7864) and October 13, 2020, withdrawal document (85 FR 64618), 
management activities (e.g., timber harvest, wildland firefighting, 
prescribed fire, and silviculture) can modify wolverine habitat, but 
this generalist species appears to be affected little by changes to the 
vegetative characteristics of its habitat. In addition, most wolverine 
breeding habitat in the contiguous United States occurs at high 
elevations in rugged terrain that is not conducive

[[Page 83769]]

to intensive forms of silviculture and timber harvest. Forest 
management activities for the purposes of reducing the risk or severity 
of wildfire are generally not a threat to wolverines in the contiguous 
United States.
    Under this interim 4(d) rule, incidental take caused by forest 
vegetation management for the purpose of wildfire mitigation that 
promotes the long-term stability and diversity of forests will not be 
prohibited. Broadly, the forest vegetation and fire management 
activities referred to above may include, but are not limited to, 
silviculture practices and forest-management activities that address 
fuels management; insect and disease impacts; vegetation management in 
existing utility rights-of-way; and wildlife-habitat management, 
including planting seedlings or sowing seeds, mechanical cuttings as a 
restoration tool in stands experiencing advancing succession, full or 
partial suppression of fires, allowing fires to burn, and survey and 
monitoring of forest health. Because no forest vegetation management 
activities for the purposes of reducing the risk or severity of 
wildfire pose any threat to the North American wolverine at the DPS 
level, we purposefully do not specify in detail what types of these 
activities are included in this exception, or how, when, or where they 
must be conducted, as long as they are conducted in accordance with 
applicable law; these activities may also vary in how they are 
conducted across the DPS' wide range. Therefore, this interim 4(d) rule 
will facilitate the continuation of forest vegetation management 
activities because these activities pose no or minimal threats to the 
North American wolverine at the DPS level and result in only de minimis 
forms of take. Forest management can also contribute to the DPS's 
conservation into the future by maintaining overall forest health in 
and adjacent to wolverine habitat. This exception, and any relevant 
future section 7 consultations with Federal agencies, also allow for 
flexibility to accommodate specific physical conditions, resource 
needs, and constraints across the DPS's range.
Incidental Trapping
    Wolverines are occasionally incidentally trapped and killed in the 
contiguous United States in the course of legal trapping for other 
species, typically wolf trapping. This occurs at low levels in a 
portion of the wolverine's breeding range (mainly Idaho and Montana) 
and does not currently represent a stressor to the wolverine in the 
contiguous United States at the population or subspecies level. Since 
2012, there have been 10 nontarget wolverine captures (average = fewer 
than 1/year) resulting in 3 mortalities in Montana (MFWP 2023, in 
litt., p. 1). In Idaho, 14 nontarget captures (0.7/year) of wolverines 
have occurred during licensed trapping activities, with no demonstrable 
trend in capture rates over the past 20 years (IDFG 2022, in litt., p. 
3). Between November 2017 and August 2022, IDFG reported that nine 
wolverines were incidentally trapped, with two resulting in mortalities 
(IDFG 2022, in litt., pp. 5, 16-22). We have no recent reports of 
wolverines incidentally trapped in other States within the range during 
the course of legal trapping activities.
    In 2021, in both Idaho and Montana, laws and regulations were 
enacted that may increase the amount of wolf trapping and the risk of 
incidental trapping of wolverines because of the use of snares, 
extended trapping seasons, and financial incentives (Service 2023, p. 
39). However, because wolverines differ from wolves in size, 
distribution, and behavior, and State laws and guidelines influence 
trappers to use trap tension, site selection, and snare height to 
reduce the likelihood of incidental capture, we expect minimal effects. 
In addition, year-round wolf trapping seasons in Idaho are limited to 
private lands, where there is very little core wolverine habitat, 
further reducing the potential for incidental taking through trapping.
    As discussed above under Overutilization for Commercial, 
Recreational, Scientific, or Educational Purposes, States within the 
North American wolverine's range in the contiguous United States have 
enacted multiple regulations and recommendations to limit incidental 
trapping mortality of wolverines. Additionally, the legal trapping that 
occurs for other species, like bobcat and marten, does not lend itself 
to wolverine incidental trapping due to the types of traps used, 
placement of those traps, and habitat in which they would be deployed. 
We expect incidental trapping of wolverines to continue to be very 
limited throughout the DPS's range.
    Incidental trapping mortality of wolverines in the contiguous 
United States is minimal and does not impact wolverines at a population 
or species level. Mowat et al. (2020, p. 221) concluded the maximum 
sustainable harvest rate for wolverines is about 8 percent. Based on a 
recent analysis of an area in Canada that was experiencing population 
declines related to overharvest, Mowat et al. (2020, p. 224) 
recommended reducing direct trapping mortality to no more than 4 
percent per year across their study area to promote wolverine 
population recovery. In the contiguous United States, where there is no 
direct trapping, incidental trapping rates have been well below this 
recommended rate. If we assume there are approximately 300 wolverines 
in the contiguous United States and assume 2 wolverine mortalities per 
year from incidental trapping (a conservative estimate from the 
incidental trapping mortalities we know of since 2012), that would be 
only 0.67 percent of the population per year. This minimal level of 
loss will not significantly impact the contiguous U.S. population of 
North American wolverines and will not inhibit conservation of the DPS. 
We conclude that the overall impact of incidental trapping that is 
conducted in accordance with State or Tribal trapping laws and 
regulations and in a manner that uses best practices to minimize 
capture and mortality of wolverines, is not expected to negatively 
affect conservation and recovery efforts for the contiguous U.S. DPS of 
the North American wolverine. Therefore, take due to this type of 
trapping will not be prohibited. Take due to trapping that is not in 
compliance with applicable State or Tribal laws or regulations and that 
results in the incidental trapping of a wolverine is prohibited and 
subject to penalties under section 9 of the Act. Any take of wolverine 
from incidental trapping should be reported to the nearest U.S. Fish 
and Wildlife Service law enforcement office and to the appropriate 
State wildlife agency or Tribal wildlife authorities within 5 days of 
occurrence. Unharmed individuals are to be released immediately.
    We anticipate that the additional take excepted by this interim 
4(d) rule will only have a minimal impact on wolverine habitat and 
individuals in the contiguous United States. The activities associated 
with scientific research, forest management for the purposes of 
reducing the risk or severity of wildfire, and legal trapping of other 
species in a manner that reduces risk to wolverines are expected to 
result in low levels of take of individuals given the limited scope and 
scale of these activities.
    We conclude that take of wolverines excepted by this interim 4(d) 
rule will be small and will not pose a significant impact on the 
conservation of the DPS as a whole. However, we recognize that there is 
some uncertainty regarding the level of take that may result and that 
there are other approaches and additional conservation measures that 
could improve the overall conservation outcome of this interim 4(d) 
rule. We

[[Page 83770]]

are seeking public comments on this interim 4(d) rule (see Public 
Comments Solicited on the Interim 4(d) Rule, below), and we will 
publish either an affirmation of this interim rule or a final revised 
rule after we fully consider all comments we receive.

Need for Interim Rule

    We initially proposed a 4(d) rule for the wolverine in 2013, in 
association with our proposal to classify the wolverine as a threatened 
species (78 FR 7864; February 4, 2013). We accepted comments on that 
2013 proposed 4(d) rule and have considered the comments we received 
regarding the proposed 4(d) rule in developing this interim 4(d) rule. 
Thus, we engaged in notice-and-comment rulemaking, and we could have 
issued the 4(d) rule as a final rule rather than as an interim rule 
with an additional comment period. However, we have elected to issue 
the 4(d) rule as an interim rule and to accept public comments to 
ensure a robust opportunity for the public to consider the prohibitions 
and exceptions prescribed, while providing protections for the 
threatened DPS and complying with our court-ordered deadline to 
finalize the listing determination.
    The Service considered segregating the 4(d) rule from the listing 
determination and issuing a revised proposed rule for notice and 
comment before finalizing the 4(d) rule. However, under 5 U.S.C. 
553(b)(3)(B) of the Administrative Procedure Act (APA), we find good 
cause to proceed without reproposing the 4(d) rule and undertaking 
notice and comment before finalizing the 4(d) rule. If the Secretary 
were to repropose a 4(d) rule and finalize it through the standard 
rulemaking process, we would be unable to finalize the protective 
regulations set forth in this interim 4(d) rule concurrently with the 
final listing rule for the DPS. This would result in no protections for 
the DPS until we complete a process to repropose and finalize a 4(d) 
rule. That outcome would be contrary to the public interest in this 
case because immediate implementation of the interim 4(d) rule when the 
species' listing is effective (see DATES, above) has the advantage of 
providing a conservation benefit to the North America wolverine in the 
contiguous United States. Under this interim 4(d) rule, the DPS will be 
protected by the general section 9(a)(1) prohibitions, with the 
aforementioned exceptions. Alternatively, another option left to the 
agency's discretion would be to have no prohibitions for a species 
determined to be threatened under the Act. However, as stated, we think 
that it is appropriate to provide some protection for this DPS now so 
that wolverines in the United States have the best chance of surviving 
in the face of climate change impacts and other threats. We find that 
this interim 4(d) rule provides appropriate protections to promote the 
conservation of the DPS across its range while providing the 
flexibility for certain otherwise lawful activities to occur without 
significantly impacting the DPS or its habitat. The final rule listing 
the contiguous U.S. DPS of the North American wolverine as a threatened 
species under the Act is published as a part of this document and is 
effective on the date specified in DATES, above. To avoid any confusion 
arising from varying effective dates, and because we cannot establish a 
4(d) rule for a species that is not yet listed, this interim 4(d) rule 
will also be effective on the date specified in DATES, above, to 
coincide with the effective date of the listing.

Public Comments Solicited on the Interim 4(d) Rule

    We request comments or information from other concerned Federal and 
State agencies, Tribes, the scientific community, or any other 
interested party concerning the interim 4(d) rule. With regard to the 
interim 4(d) rule, we particularly seek comments regarding:
    (1) Whether the 4(d) rule as a whole is necessary and advisable to 
provide for the conservation of the contiguous U.S. DPS of the North 
American wolverine.
    (2) Information concerning the extent to which we should include 
any of the section 9 prohibitions in the 4(d) rule.
    (3) Whether we should consider any additional exceptions from the 
prohibitions, such as take as a result of other categories of 
activities beyond those described, and, if so, under what conditions 
and with what conservation measures, if any.
    (4) Additional provisions the Service may wish to consider for a 
revision to the interim 4(d) rule in order to conserve, recover, and 
manage the DPS.
    Our determination to affirm or revise the interim 4(d) rule will 
take into consideration all written comments and any additional 
information we receive. Please note that comments merely stating 
support for or opposition to the interim 4(d) rule without providing 
supporting information, although noted, will not be considered. Our 
final 4(d) rule may differ from this interim 4(d) rule, based on our 
review of all information we receive during this rulemaking proceeding. 
We may change the parameters of the prohibitions or the exceptions to 
those prohibitions in the 4(d) rule if we conclude it is appropriate in 
light of comments and new information received. For example, we may 
expand the prohibitions if we conclude that the protective regulations, 
including those additional prohibitions, are necessary and advisable to 
provide for the conservation of the species. Conversely, we may 
establish additional exceptions to the prohibitions in the final rule 
if we conclude that the activities would facilitate or are compatible 
with the conservation and recovery of the species.
    Our intent is to issue an affirmation of this interim 4(d) rule or 
issue a revised 4(d) rule for the contiguous U.S. DPS of the North 
American wolverine by December 2024.
    As we state above under DATES, we are opening a 60-day public 
comment period on the interim 4(d) rule. You may submit your comments 
and materials concerning the interim 4(d) rule by one of the methods 
listed in ADDRESSES. We request that you send comments only by the 
methods described in ADDRESSES. If you submit information via https://www.regulations.gov, your entire submission--including any personal 
identifying information--will be posted on the website.
    If your submission is made via a hardcopy that includes personal 
identifying information, you may request at the top of your document 
that we withhold this information from public review. However, we 
cannot guarantee that we will be able to do so. We will post all 
hardcopy submissions on https://www.regulations.gov. Please include 
sufficient information with your comments to allow us to verify any 
scientific or commercial information you include.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this rule, will be available for 
public inspection on https://www.regulations.gov, or by appointment, 
during normal business hours, at the Pacific Region Ecological Services 
Program (see FOR FURTHER INFORMATION CONTACT).

III. Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species, and
    (b) Which may require special management considerations or 
protection; and

[[Page 83771]]

    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.

Critical Habitat Determinability

    Our regulations at 50 CFR 424.12(a)(2) state that critical habitat 
is not determinable when one or both of the following situations exist:
    (i) Data sufficient to perform required analyses are lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to identify any area that meets the definition of ``critical 
habitat.''
    When critical habitat is not determinable, the Act allows the 
Service an additional year to publish a critical habitat designation 
(16 U.S.C. 1533(b)(6)(C)(ii)).
    We reviewed the available information pertaining to the biological 
needs of the contiguous U.S. DPS of the North American wolverine and 
habitat characteristics where the DPS is located. A careful assessment 
of the economic impacts that may occur due to a critical habitat 
designation has yet to occur, and we will be working to acquire the 
complex information needed to perform that assessment. Therefore, due 
to the current lack of data sufficient to perform required analyses, we 
conclude that the designation of critical habitat for the DPS is not 
determinable at this time in accordance with 50 CFR 424.12(a)(2)(i). 
The Act allows the Service an additional year to publish a critical 
habitat designation that is not determinable at the time of listing (16 
U.S.C. 1533(b)(6)(C)(ii)).

Required Determinations

Clarity of the Rule

    We are required by E.O.s 12866 and 12988 and by the Presidential 
Memorandum of June 1, 1998, to write all rules in plain language. This 
means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in ADDRESSES. To better help us 
revise the rule, your comments should be as specific as possible. For 
example, you should tell us the numbers of the sections or paragraphs 
that are unclearly written, which sections or sentences are too long, 
the sections where you feel lists or tables would be useful, etc.

National Environmental Policy Act (42 U.S.C. 4321 et seq.)

    Regulations adopted pursuant to section 4(a) of the Act are exempt 
from the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et 
seq.) and do not require an environmental analysis under NEPA. We 
published a notice outlining our reasons for this determination in the 
Federal Register on October 25, 1983 (48 FR 49244). This includes 
listing, delisting, and reclassification rules, as well as critical 
habitat designations and species-specific protective regulations 
promulgated concurrently with a decision to list or reclassify a 
species as threatened. The courts have upheld this position (e.g., 
Douglas County v. Babbitt, 48 F.3d 1495 (9th Cir. 1995) (critical 
habitat); Center for Biological Diversity v. U.S. Fish and Wildlife 
Service, 2005 WL 2000928 (N.D. Cal. Aug. 19, 2005) (concurrent 4(d) 
rule)).

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), E.O. 13175 (Consultation and Coordination 
with Indian Tribal Governments), and the Department of the Interior's 
manual at 512 DM 2, we readily acknowledge our responsibility to 
communicate meaningfully with federally recognized Tribes on a 
government-to-government basis. In accordance with Secretary's Order 
3206 of June 5, 1997 (American Indian Tribal Rights, Federal-Tribal 
Trust Responsibilities, and the Endangered Species Act), we readily 
acknowledge our responsibilities to work directly with Tribes in 
developing programs for healthy ecosystems, to acknowledge that Tribal 
lands are not subject to the same controls as Federal public lands, to 
remain sensitive to Indian culture, and to make information available 
to Tribes. During the development of the wolverine SSA report addendum, 
we asked for information and concerns from all the federally recognized 
Tribes in the contiguous U.S. range of the North American wolverine in 
California, Colorado, Idaho, Montana, Oregon, Utah, Washington, and 
Wyoming. While we did not receive any information regarding the 
wolverine from any Tribe specific to the SSA report addendum, we remain 
committed to engaging with interested Tribes regarding the interim 4(d) 
rule, future proposed critical habitat designation, and future recovery 
planning for the contiguous U.S. DPS of the North American wolverine.

References Cited

    A complete list of references cited in this rulemaking is available 
on the internet at https://www.regulations.gov and upon request from 
the Pacific Region Ecological Services Program (see FOR FURTHER 
INFORMATION CONTACT).

Authors

    The primary authors of this rule are the staff members of the Fish 
and Wildlife Service's Species Assessment Team and the Pacific Region 
Ecological Services Program.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Plants, 
Reporting and recordkeeping requirements, Transportation, Wildlife.

Regulation Promulgation

    Accordingly, we amend part 17, subchapter B of chapter I, title 50 
of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, 
unless otherwise noted.


0
2. Amend Sec.  17.11, in paragraph (h), by adding an entry for 
``Wolverine, North American [Contiguous U.S. DPS]'' to the List of 
Endangered and Threatened Wildlife in alphabetical order under MAMMALS 
to read follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

[[Page 83772]]



----------------------------------------------------------------------------------------------------------------
                                                                                              Listing citations
           Common name              Scientific name        Where listed          Status        and  applicable
                                                                                                    rules
----------------------------------------------------------------------------------------------------------------
             MAMMALS
 
                                                  * * * * * * *
Wolverine, North American         Gulo gulo luscus...  Where found within                T   88 FR [INSERT
 [Contiguous U.S. DPS].                                 the contiguous                        FEDERAL REGISTER
                                                        U.S.A.                                PAGE WHERE THE
                                                                                              DOCUMENT BEGINS],
                                                                                              11/30/2023; 50 CFR
                                                                                              17.40(u).\4d\
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


0
3. Amend Sec.  17.40 by adding paragraph (u) to read as follows:


Sec.  17.40  Special rules--mammals.

* * * * *
    (u) North American wolverine (Gulo gulo luscus), contiguous U.S. 
DPS.
    (1) Prohibitions. The following prohibitions that apply to 
endangered wildlife also apply to the contiguous U.S. distinct 
population segment (DPS) of the North American wolverine. Except as 
provided under paragraph (u)(2) of this section and Sec. Sec.  17.4 and 
17.5, it is unlawful for any person subject to the jurisdiction of the 
United States to commit, to attempt to commit, to solicit another to 
commit, or cause to be committed, any of the following acts in regard 
to this DPS:
    (i) Import or export, as set forth at Sec.  17.21(b) for endangered 
wildlife.
    (ii) Take, as set forth at Sec.  17.21(c)(1) for endangered 
wildlife.
    (iii) Possession and other acts with unlawfully taken specimens, as 
set forth at Sec.  17.21(d)(1) for endangered wildlife.
    (iv) Interstate or foreign commerce in the course of a commercial 
activity, as set forth at Sec.  17.21(e) for endangered wildlife.
    (v) Sale or offer for sale, as set forth at Sec.  17.21(f) for 
endangered wildlife.
    (2) Exceptions from prohibitions. In regard to this DPS, you may:
    (i) Conduct activities as authorized by a permit under Sec.  17.32.
    (ii) Take, as set forth at Sec.  17.21(c)(2) through (c)(4) for 
endangered wildlife.
    (iii) Take, as set forth at Sec.  17.31(b).
    (iv) Possess and engage in other acts with unlawfully taken 
wildlife, as set forth at Sec.  17.21(d)(2) for endangered wildlife.
    (v) Take caused by scientific or research activities for wolverine 
undertaken by a biologist from a Federal agency other than the U.S. 
Fish and Wildlife Service, or a federally recognized Tribe, when acting 
in the course of their official duties, provided that such taking does 
not result in the death or permanent injury to the wolverine(s) 
involved and that the taking is reported to the nearest U.S. Fish and 
Wildlife Service law enforcement office and to the appropriate State 
wildlife agency or Tribal wildlife authorities. Activities associated 
with scientific research may include capture, anesthesia, collaring, 
tracking, genetic sampling, the use and baiting of camera and DNA 
traps, den monitoring, and aerial surveying.
    (vi) Take incidental to an otherwise lawful activity caused by:
    (A) Forest vegetation management activities for the purpose of 
reducing the risk or severity of wildfire.
    (B) Trapping of species other than wolverine, provided that the 
trapping is conducted in accordance with State or Tribal trapping laws 
and regulations, the trapping is conducted in a manner that uses best 
practices to minimize the potential for capture and mortality of 
wolverines, and any take of wolverine is reported to the nearest U.S. 
Fish and Wildlife Service law enforcement office and to the appropriate 
State wildlife agency or Tribal wildlife authorities within 5 days of 
occurrence. Unharmed individuals are to be released immediately.

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-26206 Filed 11-29-23; 8:45 am]
BILLING CODE 4333-15-P