[Federal Register Volume 88, Number 166 (Tuesday, August 29, 2023)]
[Rules and Regulations]
[Pages 59698-59727]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17675]



[[Page 59697]]

Vol. 88

Tuesday,

No. 166

August 29, 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; Foothill Yellow-Legged 
Frog; Threatened Status With Section 4(d) Rule for Two Distinct 
Population Segments and Endangered Status for Two Distinct Population 
Segments; Final Rule

  Federal Register / Vol. 88 , No. 166 / Tuesday, August 29, 2023 / 
Rules and Regulations  

[[Page 59698]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2021-0108; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BE90


Endangered and Threatened Wildlife and Plants; Foothill Yellow-
Legged Frog; Threatened Status With Section 4(d) Rule for Two Distinct 
Population Segments and Endangered Status for Two Distinct Population 
Segments

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
endangered status for two distinct population segments (DPSs) and 
threatened status for two DPSs of the foothill yellow-legged frog (Rana 
boylii), a stream-dwelling amphibian from Oregon and California. After 
review of the best scientific and commercial information available, we 
have determined endangered status for the South Sierra and South Coast 
DPSs and threatened status for the North Feather and Central Coast DPSs 
of the foothill yellow-legged frog under the Endangered Species Act of 
1973 (Act), as amended. This rule adds the four DPSs to the List of 
Endangered and Threatened Wildlife and extends the Act's protections to 
these DPSs. We also finalize rules under the authority of section 4(d) 
of the Act for the North Feather and Central Coast DPSs that provide 
measures that are necessary and advisable to provide for the 
conservation of these two DPSs. We have determined that designation of 
critical habitat for the four DPSs is not determinable at this time.

DATES: This rule is effective September 28, 2023.

ADDRESSES: This final rule is available on the internet at https://www.regulations.gov under Docket No. FWS-R8-ES-2021-0108. Comments and 
materials we received, as well as supporting documentation we used in 
preparing this rule, are available for public inspection at https://www.regulations.gov at Docket No. FWS-R8-ES-2021-0108.

FOR FURTHER INFORMATION CONTACT: Michael Fris, Field Supervisor, U.S. 
Fish and Wildlife Service, Sacramento Fish and Wildlife Office, 2800 
Cottage Way, Sacramento, CA 95825; telephone 916-414-6700. 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

    Why we need to publish a rule. 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 endangered 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 
South Sierra and South Coast DPSs of the foothill yellow-legged frog 
both meet the definition of an endangered species and the North Feather 
and Central Coast DPSs of the foothill yellow-legged frog both meet the 
definition of a threatened species; therefore, we are listing them as 
such. We have determined that designation of critical habitat for the 
four DPSs is not determinable at this time. Listing a species or DPS 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 rule lists the South Sierra and South 
Coast DPSs of the foothill yellow-legged frog as endangered and lists 
the North Feather and Central Coast DPSs of the foothill yellow-legged 
frog as threatened with rules issued under section 4(d) of the Act 
(``4(d) rules'').
    The basis for our action. Under the Act and our 1996 DPS policy (61 
FR 4722; February 7, 1996), we may determine that a species or DPS is 
endangered or threatened 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 following threats are driving the status of the foothill 
yellow-legged frog within the areas occupied by the DPSs: altered 
hydrology (Factor A; largely attributable to dams, water diversions, 
channel modifications), nonnative species (Factors C and E), and the 
effects of climate change (Factor E; exacerbating drought, high-
severity wildfire, extreme flood conditions). Other threats currently 
impacting the species include disease and parasites, agriculture 
(including pesticide drift), mining, urbanization (including 
development and roads), and recreation.
    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. Due to our statutory 
requirements to complete a final determination within 12 months of 
issuing a proposed rule, we have not yet been able to obtain the 
necessary economic information needed to develop a proposed critical 
habitat designation for the four DPSs of the foothill yellow-legged 
frog. Therefore, we find that designation of critical habitat for the 
four DPSs is currently not determinable. Once we obtain the necessary 
economic information, we will propose critical habitat designations for 
the four DPSs.

Previous Federal Actions

    On December 28, 2021, we published in the Federal Register (86 FR 
73914) a proposed rule to list the North Feather and Central Coast DPSs 
of the foothill yellow-legged frog as threatened and the South Sierra 
and South Coast DPSs of the foothill yellow-legged frog as endangered 
under the Act (16 U.S.C. 1531 et seq.). In that proposed rule, we also 
completed not-warranted 12-month findings for the North Coast and North 
Sierra DPSs of the foothill yellow-legged frog. The proposed rule 
opened a 60-day comment period, ending February 28, 2022. On February 
28, 2022, in response to a request we received during the comment 
period, we published in the Federal Register (87 FR 11013) a document 
extending the comment period on the December 28, 2021, proposed rule 
for an additional 30 days, ending March 30, 2022. Please refer to the 
December 28, 2021, proposed rule for information regarding the status 
of the North Coast and North Sierra DPSs, as well as other previous 
Federal actions concerning the foothill yellow-legged frog.

Peer Review

    A species status assessment (SSA) team prepared an SSA report for 
the foothill yellow-legged frog. The SSA team was composed of Service 
biologists, in consultation with other species experts. The SSA report

[[Page 59699]]

represents a compilation of the best scientific and commercial data 
available concerning the biological status of the species and the four 
DPSs we are listing, including the impacts of past, present, and future 
factors (both negative and beneficial) affecting them.
    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 of 
listing actions under the Act, we solicited independent scientific 
review of the information contained in the foothill yellow-legged frog 
SSA report. We received peer review from three appropriate specialists 
regarding the SSA. The peer reviews can be found at https://www.regulations.gov. In preparing the proposed rule, we incorporated 
the results of these reviews, as appropriate, into the SSA report, 
which was the foundation for the proposed rule and this final rule. A 
summary of the peer review comments and our responses can be found in 
the Summary of Comments and Recommendations below. The peer review 
comments as well as a copy of the most current SSA report (Service 
2023, entire) and other materials relating to this rule can be found on 
https://www.regulations.gov at Docket No. FWS-R8-ES-2021-0108.

Summary of Changes From the Proposed Rule

    In preparing this final rule, we reviewed and fully considered the 
comments we received during the comment period on our December 28, 
2021, proposed rule (see 86 FR 73914, December 28, 2021; 87 FR 11013, 
February 28, 2022). This final rule reflects minor, nonsubstantive 
changes to the SSA report and clarification of threat information based 
on the comments we received, as discussed below under Summary of 
Comments and Recommendations. However, the information we received 
during the comment period did not change our determinations for the 
four DPSs: we found in the December 28, 2021, document that the North 
Coast and North Sierra DPSs are not warranted for listing under the 
Act.

Summary of Comments and Recommendations

    In the proposed rule published in the Federal Register on December 
28, 2021 (86 FR 73914), we requested that all interested parties submit 
written comments on the proposal by February 28, 2022. On February 28, 
2022, we published in the Federal Register (87 FR 11013) a document 
extending the comment period by 30 days, until March 30, 2022. We also 
contacted appropriate Federal and State agencies, Tribes, scientific 
experts and organizations, and other interested parties and invited 
them to comment on the proposal. Newspaper notices inviting general 
public comment were published throughout the range of the species in 
the Monterey Herald, Oregonian, Sacramento Bee, San Luis Obispo 
Tribune, Santa Barbara News-Press, and Ventura County Star. We did not 
receive any requests for a public hearing. All substantive information 
regarding the four DPSs received during the comment period has either 
been incorporated directly into the SSA or this final determination as 
appropriate. A summary of the substantive comments is outlined below.

Peer Reviewer Comments

    As discussed in Peer Review above, we received comments from three 
peer reviewers on the draft SSA report. We reviewed all comments we 
received from the peer reviewers for substantive issues and new 
information regarding the information and analysis contained in the SSA 
report. The peer reviewers generally concurred with our information, 
methods, and conclusions, and they provided additional information, 
clarifications, and suggestions to improve the SSA report. Peer 
reviewer comments addressed issues related to the effects of disease, 
mining, wildfire, climate change, and watershed impairment on the 
species, as well as its preferred hydraulic conditions, potential for 
species hybridization, breeding conditions, metapopulation dynamics, 
and elevational range. All substantive peer review comments were 
incorporated into version 2.11 of the SSA report (Service 2023, entire) 
as appropriate. A summary of the peer review comments is outlined 
below.
    (1) Comment: A peer reviewer commented that there was insufficient 
evidence to claim that threats to the species from the disease 
chytridiomycosis primarily affects populations in the [Central Coast, 
South Coast, and South Sierra DPSs] because of a lack of studies of 
chytridiomycosis in the species in the more northern DPSs.
    Our Response: We have changed the latest draft of the SSA to remove 
reference to chytridiomycosis as primarily affecting populations in the 
Central Coast, South Coast, and South Sierra DPSs.
    (2) Comment: A peer reviewer commented that tributary habitat is 
not necessarily ``non-breeding'' because the species can use also use 
tributary habitat for breeding, depending on environmental conditions 
at the time, such as in the Sierra Nevada Mountains.
    Our Response: We have changed the latest draft of the SSA to 
reflect that tributary habitat can also be used as breeding habitat 
when environmental conditions are favorable. Specifically, we updated 
the Upland and Tributary (Nonbreeding) Habitat Section (Section 4.8) to 
note that tributary habitat can be used as breeding habitat in 
favorable environmental conditions.
    (3) Comment: A peer reviewer commented that the conclusions from 
Dever et al. (2007) are not necessarily applicable for use in 
delineating metapopulations. Specifically, Dever et al. (2007) found 
genetic differentiation between subpopulations along the Eel River at 
distances of 10 kilometers (km) between subpopulations. The peer 
reviewer commented that they had observed genetic connectivity between 
populations at distances greater than 10-km along the North Fork of the 
American River and thus using a 10-km distance as a benchmark distance 
for genetic differentiation may not be accurate.
    Our Response: We have changed the latest draft of the SSA to 
reflect that a metapopulation can maintain genetic cohesion with 
distances greater than 10-km between populations. Specifically, we 
removed discussions of using the 10-km distance observed by Dever et 
al. (2007) to delineate metapopulations from the Metapopulation 
Structure (Section 2.9) and Metapopulation Connectivity (Section 5.5) 
Sections.
    (4) Comment: A peer reviewer commented that Figure 33, a diagram of 
the interactions between drying and drought on habitat elements and 
demographic and distribution parameters, should reflect that drought 
has a direct effect on the abundance of the species.
    Our Response: We changed Figure 33 during revisions from v1.0 to v 
2.0 of the SSA to reflect this relationship between drying and drought 
and species abundance.

Federal Agency Comments

    (5) Comment: The U.S. Forest Service (Sierra National Forest) 
commented that they had performed surveys for the species in the Jose 
and Mill Creek basin following the 2020 Creek Fire and that they 
detected the species in only one survey reach of Mill Creek, Fresno 
County, California. In addition, the Plumas National Forest informed us 
that a foothill yellow-legged frog observation in their Natural 
Resource Information Strategy Project (NRIS) Aquatic Survey

[[Page 59700]]

database located in the disjunct eastern portion of the North Feather 
DPS was erroneous and should not be used to inform the geographic 
extent of the species in the North Feather DPS.
    Our Response: The current version of the SSA report (version 2.0) 
reflects the presence of the species in Mill Creek based on information 
provided to us. For the North Feather DPS, we reviewed and concurred 
with the California Department of Fish and Wildlife (CDFW) assessment 
of the DPS's range based on multiple observations of the DPS prior to 
1969 (CDFW 2019b, p. 32), and thus we did not use the Forest Service's 
NRIS database entry to inform our delineation of the DPS's range or the 
DPS boundary.

Comments From Local Government

    (6) Comment: The Tulare County Board of Supervisors commented that 
they were opposed to the designation of the South Sierra DPS as 
endangered because of their concern that management of the DPS would 
reduce water availability for agriculture. They stated that the South 
Sierra DPS has not been adequately surveyed, and, therefore, the DPS 
may be more abundant. The board recommended addressing wildfire 
management and removing invasive species as an alternative to listing 
the South Sierra DPS.
    Our Response: At this time, we have no information to indicate that 
listing or management of the South Sierra DPS would reduce water 
availability for agriculture or other purposes. We acknowledge the 
importance of water availability and delivery for both agricultural and 
municipal purposes throughout the San Joaquin Valley and California, 
and we will cooperate and assist water management and delivery entities 
as they meet the water needs of the public. With regard to the 
sufficiency of occurrence data available for determining the status of 
the South Sierra DPS, the Act requires our listing determinations to be 
based solely on the best scientific and commercial information 
available at the time of our rulemaking; using that information, we 
determine whether the listable entity meets the Act's definition of an 
endangered or a threatened species. In our efforts to determine the 
status of the species and DPSs (including the South Sierra DPS), we 
contacted numerous Federal, State, and academic researchers and species 
experts, as well as other land management entities, and requested 
occurrence information, survey information, and information regarding 
threats impacting the foothill yellow-legged frog and its habitat. We 
have determined that the information we have received is the best 
scientific and commercial information available at this time regarding 
occurrence information for the DPSs, including the South Sierra DPS. 
With regard to alternative management strategies as opposed to listing 
the DPS under the Act, both wildfires and invasive species are 
identified as threats to the South Sierra DPS, but they are only two of 
many threats currently impacting the DPS and its habitat. We have 
determined that listing the South Sierra DPS as endangered will provide 
the regulatory protections needed to prevent further decline of the DPS 
and its habitat.

Public Comments

    (7) Comment: A commenter requested the Service work with water 
management agencies to ensure that water management practices are 
beneficial to the foothill yellow-legged frog. Specifically, the 
commenter was concerned that current dam relicensing efforts on the 
Stanilaus River have not engaged stakeholders and will not consider the 
needs of the species. The commenter requested the Service create 
guidelines for water management practices by dam licensees, formulate 
mitigation requirements for water projects, require water agencies to 
fund recovery efforts, prioritize removal of nonnative invasive 
predators of the species, include protective measures for the species 
in existing National Forest Plans, and engage the State Water Board in 
``formal consultation'' regarding suction dredging activities.
    Our Response: While we are not the lead government agency or have 
the decision-making authority for the actions that were referenced in 
this comment, as part of our mission to conserve and protect sensitive 
species and their habitats, we are required to coordinate with Federal 
regulatory and land management agencies such as the Federal Energy 
Regulatory Commission (responsible for licensing privately owned dams), 
U.S. Army Corps of Engineers (regulation authorized by the Clean Water 
Act (33 U.S.C. 1251 et seq.)), the U.S. Forest Service (Forest 
Service), Bureau of Land Management (BLM), and the National Park 
Service (NPS). Part of this coordination is to provide recommendations 
for the types of actions identified by the commenter. These Federal 
entities are also required under sections 2 and 7 of the Act to use 
their authorities to conserve endangered and threatened species and 
their habitats and to consult with us on their activities. Federally 
approved, authorized, or funded activities that may adversely affect 
listed species or jeopardize a listed species' continued existence 
require formal consultation under section 7 of the Act. We also 
coordinate with our State partners, such as the California Department 
of Fish and Wildlife and the State Water Resource Control Board, to 
assist in protecting and conserving listed and sensitive species and 
their habitats. Suction dredging activities within streams by 
nonfederal entities are managed by the State, unless Federal 
authorization, funding, or permitting is required, at which point we 
would coordinate with the Federal entity on such activities.
    (8) Comment: Several commenters disagreed with our proposed 
determinations for the Central Coast and North Feather DPSs and 
recommended endangered rather than threatened status. The commenters' 
reasoning included information from the SSA report that states the 
Central Coast DPS has substantially reduced resiliency because of poor 
occupancy, poor connectivity, and a relatively high risk of decline, 
and that the DPS faces substantial threats. The commenters also note 
that the SSA identifies a reduction in resiliency under the mean change 
scenario, which would put the Central Coast DPS at risk of functional 
extirpation or extirpation within 40 years. The commenters also state 
that the SSA report and proposed rule include discussion of the 
beneficial effects of two habitat conservation plans (HCPs) (East 
Contra Costa HCP and Santa Clara Valley HCP) that provide conservation 
for the Central Coast DPS despite the DPS appearing to be absent from 
one of the HCP planning areas (East Contra Costa HCP). The commenters 
reference foothill yellow-legged frog information in the 2006 Contra 
Costa HCP that states the species had not been documented in the 
planning area (Jones & Stokes 2006, appendix D). The commenters' 
rationale for endangered status for the North Feather DPS is that the 
CDFW determined that the DPS is endangered under the California 
Endangered Species Act (CESA), and, therefore, a Federal listing under 
the Act should be endangered as well.
    Our Response: In making our status determinations for the Central 
Coast and North Feather DPSs of the foothill yellow-legged frog, we 
used the best scientific and commercial data available; we conclude 
that our threatened determinations continue to be appropriate based on 
whether the factors influencing each DPS's status and the DPS's 
response are occurring now or in the future. In the proposed rule and 
this final rule, we outline our

[[Page 59701]]

reasoning for our threatened status determinations for the Central 
Coast and North Feather DPSs of the foothill yellow-legged frog. One 
aspect in determining whether a species or DPS is considered either 
endangered or threatened under the Act is whether the threats facing 
the entity are influencing the current or future conditions of the DPS 
to the extent that we find that the entity requires listing under the 
Act. A threatened determination reflects that the threats may act on 
the species' future condition such that it is likely to become 
endangered in the foreseeable future throughout all or a significant 
portion of its range; an endangered determination means that the 
species is in danger of extinction now, throughout all or a significant 
portion of its range.
    We acknowledge the commenter's characterization from the SSA report 
for the Central Coast DPS's current and future condition. The 
population size and abundance for the Central Coast DPS has 
historically been and continues to be small, and this population 
information did influence our characterization of the DPS's resiliency. 
However, we do not agree with the commenter's conclusions that the 
Central Coast DPS should be listed as endangered under the Act. Mainly 
The Central Coast DPS currently sustains numerous populations and 
habitat distributed throughout the DPS's range with the populations in 
the southern portion of its range largely intact and having limited or 
no development pressure and those populations in the northern part of 
the DPS's range are located in areas not associated with largescale 
urbanization and have conservation measures in place to protect the 
species or its habitat. The northern populations have been impacted by 
development; however, these impacts are associated mostly with past and 
not current development pressure. In our determination of the current 
and future condition of the Central Coast DPS, we consider not only the 
resiliency of the DPS but also its redundancy and resiliency (all 3R's) 
as outlined in our guidance for assessing the status of a species 
(Service 2016, entire). Although the modeling identified in the SSA 
report identified the resiliency of the Central Coast DPS as reduced, 
this reduction would be occurring in the future, which is consistent 
with our threatened determination. Because the current threats facing 
the DPS are not influencing the current status of existing populations 
of the DPS to the degree that it is currently in danger of extinction, 
we do not find that the DPS warrants endangered status. However, based 
on our projections of future occupancy, modeled future risk of decline, 
and the increased threats from future drought conditions and increasing 
water demands, as well as increased wildfire frequency and intensity 
due to future climate change conditions, we continue to find that the 
appropriate listing status under the Act for the Central Coast DPS is 
threatened.
    We also acknowledge that the East Contra Costa County HCP planning 
document does state that occupancy of the foothill yellow-legged frog 
in the HCP's planning area is unknown (Jones & Stokes 2006, appendix 
D). However, the document also cites older survey information and 
concludes that there are potential occurrences that are concentrated 
around the Mount Diablo area (Jennings and Hayes 1994, pp. 66-69). In 
2019, the CDFW's status assessment of the species for State listing 
does not rule out occupancy in and around Mount Diablo (CDFW 2019b, p. 
42, figure 16). Based on this information, we included the East Contra 
Costa County HCP in our discussion regarding conservation actions being 
implemented for the Central Coast DPS of the foothill yellow-legged 
frog (see East Contra Costa County HCP (Jones & Stokes 2006, chapter 
5)).
    In our analysis of the status of the North Feather DPS, we looked 
at the currently known occurrence records from the 2010-2020 timeframe, 
the current implementation of modified flow regime measures to mimic 
more natural hydrograph, the effects of the modified flows on improving 
current habitat conditions, and the current efforts of in-situ and ex-
situ rearing efforts on enhancing populations of the North Feather DPS. 
All these factors informed our decision that the current condition of 
the DPS, although reduced, still exhibits sufficient resiliency, 
redundancy, and representation and would provide for, at a minimum, 
pockets of favorable conditions that allow the North Feather DPS to 
currently sustain its existing populations in the wild. Therefore, the 
current condition of the North Feather DPS has not been reduced to such 
a degree to consider it in danger of extinction throughout its range. 
However, the impacts from future effects of climate change related to 
changes in snowpack, precipitation timing, and drought (intensity, 
frequency, and duration), and from the climate-related impacts to 
wildfire severity, led us to conclude that the DPS will likely become 
in danger of extinction in the future and is appropriately identified 
as a threatened species under the Act. The State's determination of 
endangered under CESA looks at the species within California, and an 
endangered status under CESA, although similar, does not equate to the 
standards set forth for determining an entity to be endangered under 
the Act.
    (9) Comment: Several commenters assert that we did not consider the 
effects of the invasive algae Didymosphenia geminata on the foothill 
yellow-legged frog. The commenters also cited to CDFW's determination 
that the North Sierra (Northeast/Northern Sierra) DPS is threatened 
under CESA in support of their view that the North Sierra and North 
Coast DPSs should be listed as threatened under the Act.
    Our Response: While we did not specifically discuss the effects of 
the invasive aquatic diatom Didymosphenia geminata, commonly known as 
didymo or rock snot, in the SSA report, we did discuss the importance 
of having healthy ecosystems with suitable macroalgae communities and 
rock substrate that provide unaltered aquatic habitat for appropriate 
foraging opportunities for the foothill yellow-legged frog as part of 
the species' needs (see SSA report (Service 2023, chapter 4, pp. 52-
66)). In our SSA report, we referenced research specific to D. geminata 
(Furey et al. 2014, entire) in relation to regulated and unregulated 
stream reaches associated with dams. This study examined the potential 
impacts of how altered hydrologic conditions may change the composition 
of the algae community and how these changes may limit growth of 
foothill yellow-legged frog tadpoles. Moreover, as a result of the 
comment, we reviewed the information and updated our SSA report to 
reflect specific information on D. geminata and how it was used in our 
analysis and status determinations.
    In response to the comment that we should follow the State's 
listing determination, we note that under the Act, we are required to 
use the best scientific and commercial information available when 
making a listing determination. For our listing determination we use 
information on occurrences, occupancy, abundance, and population trends 
and worked with U.S. Geological Survey (USGS) researchers to complete a 
rangewide population viability analysis (PVA) for the foothill yellow-
legged frog (Rose et al. 2020, entire). We used the information from 
the PVA to inform each DPS's current condition (Service 2023, chapter 
8, pp. 127-172) and potential future condition (Service 2023, chapter 
9, pp. 173-199). The PVA and

[[Page 59702]]

associated modeling was completed in 2020, and thus was not available 
at the time the State made its listing determination under the CESA in 
2019. In addition, the processes and criteria used to determine the 
listing status of a species under the CESA and the Act, although 
similar, are not completely interchangeable as regulatory mechanisms. 
The Service must conduct its independent analysis regarding threats in 
order to make its determination under the Act. It would not be 
appropriate for the Service to simply adopt the State's determination 
of threatened status for the North Sierra DPS without providing 
specific information regarding threats or conducting an analysis.
    Our determination of status of the North Coast DPS is contained in 
the December 28, 2021, 12-month finding and proposed rule (86 FR 73936-
73938).
    (10) Comment: A commenter stated that the Service is required to 
designate critical habitat at the time a species is proposed for 
listing if such designation is prudent and determinable. The commenter 
contends that the Service's justification of not having completed an 
economic analysis should not impede the Service from designation of 
critical habitat for the species. The commenter stated that a delay in 
designation will further hamper conservation of the foothill yellow-
legged frog.
    Our Response: We acknowledge our responsibilities to determine 
critical habitat for a species or DPS at the time of listing if such 
designation is both prudent and determinable. As we stated in our 
proposed listing rule (see 86 FR 73942) and below (see Critical Habitat 
Determinability), a careful assessment of the economic impacts that may 
occur due to a critical habitat designation is still ongoing. Under our 
regulations at 50 CFR 424.19 and policies for designating critical 
habitat, we are required to complete an economic analysis of the 
incremental costs related to the designation and whether those costs 
exceed certain thresholds and make that draft economic analysis 
available for public comment at the time of the proposed rule to 
designate critical habitat. The economic analysis is not a 
discretionary action we can avoid completing prior to issuing a 
proposed rule to designate critical habitat. We will publish a proposed 
critical habitat designation following completion of our draft economic 
analysis.
    (11) Comment: Several commenters requested the Service develop a 
section 4(d) rule under the Act to exempt timber harvest practices if 
the timber harvest activities follow the California Forest Practice 
Rules. The commenters indicated that the beneficial effect of these 
California Forest Practice Rules is indicated by the continued presence 
of the species within timber harvest areas.
    Our Response: The 4(d) rules excepting certain activities from 
section 9 prohibitions against take for the North Feather and Central 
Coast DPSs promote conservation of the species by encouraging 
management of the species' stream habitat and landscape in ways that 
meet both resource management considerations and the conservation needs 
of the species. Specifically, the 4(d) rules we are making final in 
this document (see Regulation Promulgation, below) except wildfire 
prevention and suppression activities, fuels reduction activities 
related to forest management, and habitat restoration efforts that 
benefit the DPSs and their habitats. Such activities are often 
identified in timber harvest plans required under the California Forest 
Practice Rules. However, because the habitat and condition of the DPSs 
being listed are variable and timber harvest or other timber management 
activities are usually site-specific, we have determined that an 
exception to all activities that follow the California Forest Practice 
Rules is not appropriate for conservation of the North Feather and 
Central Coast DPSs and that the current 4(d) exceptions will provide 
sufficient regulatory relief for forest management and fire prevention 
activities that benefit the species and their habitats and allow for 
conservation of the two threatened DPSs.
    (12) Comment: A commenter provided information on current 
management efforts for riparian areas on the Stanislaus River in 
Tuolumne County and stated that these efforts are sufficient to protect 
the species in this area.
    Our Response: We acknowledge that the habitat restoration and 
current management efforts identified along the Stanislaus River 
presented by the commenter may benefit the South Sierra DPS and its 
habitat. However, we are listing the South Sierra DPS due to the 
numerous and persistent threats across multiple drainages throughout 
the range of the DPS. We will take into consideration the management 
efforts along the Stanislaus River during any consultation on 
activities occurring in the area under our section 7 process, permit 
activities occurring under section 10 of the Act, or through other 
mechanisms such as our safe harbor process.
    (13) Comment: A commenter presented breeding information from the 
North Fork of the Mokelumne River and requested the Service place 
guidelines on hydroperiods and require conservation measures as part of 
the hydropower licensing process, update rangeland management 
guidelines, and encourage research on the effect of hydroperiod regimes 
on species recovery.
    Our Response: The breeding information presented by the commenter 
contributed to our understanding of the species' oviposition sites in 
the Mokelumne River watershed, and we added this information to the SSA 
report (Service 2023, pp. 16 and 55). However, the information does not 
change our position on the South Sierra DPS' status regarding listing. 
While we are not the lead government agency or have the decision-making 
authority for hydropower licenses or rangeland management, we will use 
our authorities under the Act to encourage Federal agencies and others 
(e.g., Federal Energy Regulatory Commission, U.S. Forest Service, 
Bureau of Land Management, nonprofit land management entities, local 
water management entities) to include measures in their decisions that 
will promote the recovery of the species.
    (14) Comment: Several commenters provided additional foothill 
yellow-legged frog occurrence information for the Tuolumne and South 
Fork American River watersheds in the range of the South Sierra DPS of 
the foothill yellow-legged frog and stated that the additional records 
were evidence that foothill yellow-legged frog populations are 
increasing in the watersheds following voluntary implementation of a 
flow management regime intended to reduce impacts on aquatic species 
and recommended we take this information into consideration in our 
listing determination for the South Sierra DPS.
    Our Response: The provided survey information extends our 
understanding of the distribution of the foothill yellow-legged frog in 
the Lumsden Reach of the Tuolumne River by about one-half of a river 
mile and our knowledge of abundance of foothill yellow-legged frogs in 
both the identified areas of the Tuolumne River and South Fork of the 
American River. As discussed in the SSA report and in our proposed rule 
and this final rule, alterations of stream hydrology and flows can have 
a large negative influence on foothill yellow-legged frog distribution, 
abundance, and metapopulation dynamics (Hayes et al. 2016, pp. 24-25; 
Yarnell et al. 2020, entire; Service 2023, figure 21, p. 77, section 
7.1). We also stated that measures taken on regulated streams to 
account for the foothill yellow-legged frog and its ecological needs 
have

[[Page 59703]]

improved foothill yellow-legged frog habitat and persistence in some 
areas; however, modified flow regimes are not the only threat facing 
the South Sierra DPS. Other factors, including, but not limited to, the 
effects of climate change, habitat alteration, and nonnative predators, 
also are impacting the DPS and its habitat. Due to the increased 
attention by researchers, land and water managers, and the public to 
the State listing of the foothill yellow-legged frog and now this final 
listing rule, we expect additional information to become available 
regarding the distribution of the foothill yellow-legged frog, which 
will increase our knowledge of the status of the species. However, 
based on the abundance of past and current research regarding the 
species, we do not anticipate that this information will represent a 
significant change to the distribution of the species or DPSs such that 
it would change our determinations regarding listing. Therefore, given 
the range of threats impacting the South Sierra DPS of foothill yellow-
legged frog and its habitat now and info the future, we continue to 
find that listing the DPS under the Act is warranted and finalize those 
determinations in this rule.
    (15) Comment: A commenter expressed concerns that the geographic 
division between the North Sierra DPS and South Sierra DPS was based on 
insufficient data and that habitat on the North Fork American River in 
the range of the North Sierra DPS should not be split from the South 
Fork American River in the range of the South Sierra DPS based on 
presumed historical genetic connectivity between these forks of the 
American River.
    Our Response: We identified geographic boundaries between the North 
Sierra DPS and South Sierra DPS along the North Fork and South Fork 
American Rivers. The extend and boundaries of each DPS was based on the 
CDFW's final status review of the species (A Status Review of the 
Foothill Yellow-Legged Frog (Rana Boylii) in California (CDFW 2019b, 
entire)), except for the area for the North Coast DPS in Oregon 
(Service 2023, section 2.6 ``Genetic Clades'') since the State's 
responsibility only includes California. The information used to 
determine the boundaries of each DPS included genetic information from 
researchers that divided the species into numerous clades (McCartney-
Melstad et al. 2018, entire; Peek 2018, entire). The clades in both 
studies were found to be deeply divergent and geographically cohesive. 
We used the best scientific and commercial information available to 
determine the location and extent of the areas for each DPS identified. 
Additionally, the Service reviewed the best available scientific and 
commercial data and concurred with the State's geographic boundaries. 
The Act provides for revision of listing and critical habitat rules 
upon receipt of new scientific information. If the Service receives new 
scientific information regarding the contemporary genetic relationships 
or other relevant factors between populations in the North Fork and 
South Fork of the American River, then we will review this information 
and revise DPS geographic boundaries as appropriate.
    (16) Comment: A commenter stated that our proposed 4(d) rule was 
arbitrary and capricious because we did not assess the costs and 
benefits of the rule and, therefore, did not establish that the 
proposed 4(d) rule was necessary and advisable. Additionally, the 
commenter stated that the proposed 4(d) rule requires analysis under 
the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.) 
and Regulatory Flexibility Act (5 U.S.C. 601 et seq.). An additional 
commenter stated that the proposed 4(d) rules for the North Feather DPS 
and Central Coast DPS should also exempt actions in compliance with 
California Forest Practice Rules and CDFW's lake and streambed 
alteration permits, as well as livestock grazing. The commenter was 
concerned that listing of the species would affect timber harvest 
activities, water management, and pesticide applications for 
agriculture. The commenter stated that doing so would benefit the 
species.
    Our Response: In 1982, Congress amended the Act to add the 
requirement that listing determinations are to be made solely on the 
basis of the best scientific and commercial data available. In the 
Conference Report for the 1982 amendments to the Act, Congress 
specifically stated that economic considerations are not to be 
considered in determinations regarding the status of species and that 
the economic analysis requirements of Executive Order 12291 and such 
statutes as the Regulatory Flexibility Act do not apply to any phase of 
determining the listing status of an entity under the Act. If we 
determine that a species or DPS is threatened under the Act, part of 
our consideration for completing the listing process is to consider 
what options are necessary and advisable to provide for the 
conservation of the species or DPS under section 4(d) of the Act. As a 
result, a cost benefit analysis is not part of the process required to 
propose or finalize a section 4(d) rule.
    We are also not required to complete a NEPA analysis for section 
4(d) rules promulgated at the time the species or DPS is concurrently 
being considered for listing, or listed, under the Act. This is because 
NEPA would conflict with the requirement in section 4(b) of the Act 
that classification decisions be made solely on the basis of the best 
scientific and commercial data available regarding the five factors set 
out in section 4(a)(1) of the Act. Applying NEPA to a concurrent 
section 4(d) rule could cause a similar conflict with the requirement 
in section 4(d) that we issue for threatened species such regulations 
as we deem necessary and advisable to provide for the conservation of 
such species. We published a notice outlining our reasons for this 
determination in the Federal Register on October 25, 1983 (48 FR 
49244).
    In establishing exceptions to regulations under a 4(d) rule, our 
guidance states that we should identify and incentivize known 
beneficial actions for the species, as well as rules that remove the 
regulatory burden on forms of take that are considered inconsequential 
to the conservation of the species and put in place protections that 
will both prevent the species from becoming endangered and promote the 
recovery of species. Although the State's Forest Practice Rules and 
streambed alteration permitting processes may include measures to 
conserve foothill yellow-legged frog habitat, the activities 
undertaken, in some cases, may also involve more than minimal impacts 
on the DPSs by removing habitat or having direct or indirect impacts on 
individuals. As a result, we do not consider including these measures 
as part of our species specific 4(d) rule appropriate for the two DPSs. 
We find that the section 4(d) rules for the North Feather and Central 
Coast DPSs are necessary to provide significant benefits for 
conservation of the species and are not arbitrary and capricious. In 
the proposed rule and this final rule to list the North Feather and 
Central Coast DPSs as threatened, we outline our rationale and 
establish our reasoning on why the 4(d) rules are necessary and 
advisable to provide for the conservation of the two DPSs (see December 
28, 2021, proposed rule at 86 FR 73939-73941 and Determination of 
Status for the Foothill Yellow-Legged Frog, below).
    (17) Comment: A commenter stated that existing protections for the 
species under CESA are sufficient to protect the species and, 
therefore, regulations under the Act are not necessary.

[[Page 59704]]

    Our Response: We were petitioned to determine the listing status of 
the foothill yellow-legged frog under the Act. Once we are petitioned 
to list a species, we are required to complete our regulatory processes 
regardless of any State listing determination. Although the regulations 
implementing protections for listed species under the CESA and the Act 
are similar, we cannot defer to any State listing. Under requirements 
of the Act, we must conduct the required analysis and list the species 
if it is found to be warranted.

I. Final Listing Determination

Background

    Below is a brief description of the foothill yellow-legged frog, 
its habitat, distribution, and information regarding our determination 
of DPSs under our 1996 DPS policy (61 FR 4722; February 7, 1996); for a 
thorough discussion of the ecology and life history of the species, the 
species' biological and ecological needs, as well as factors 
influencing those needs, please see the SSA report (Service 2023, 
chapter 2, pp. 15-34).

Distinct Population Segment Conclusion

    Our DPS policy directs us to evaluate whether populations of a 
species are separate from each other to the degree they qualify as 
discrete segments and whether those segments are significant to the 
remainder of the species to which it belongs. Based on an analysis of 
the best available scientific and commercial data, including recent 
genetic information and research (McCartney-Melstad et al. 2018, 
entire; Peek 2018, entire), we conclude that the North Feather, South 
Sierra, Central Coast, and South Coast clades of the foothill yellow-
legged frog's range are each discrete due to their marked genetic 
separation. Furthermore, we conclude that each of the four clades of 
the foothill yellow-legged frog's range being listed are significant, 
based on evidence that a loss of any of the population segments would 
result in a significant gap in the range of the taxon and on evidence 
that the discrete population segments differ markedly from other 
populations of the species in their genetic characteristics. Therefore, 
we conclude that the four clades within the foothill yellow-legged 
frog's range being listed are both discrete and significant under our 
DPS policy and are, therefore, unique entities under the Act. For 
additional information regarding taxonomy, genetic information, and our 
DPS determinations according to our 1996 DPS policy (61 FR 4722; 
February 7, 1996), see the December 28, 2021, proposed rule (86 FR 
73916-73920).

Species Information

    The foothill yellow-legged frog is a small- to medium-sized stream-
dwelling frog with fully webbed feet and rough pebbly skin. Coloring of 
the foothill yellow-legged frog is highly variable but is usually light 
and dark mottled gray, olive, or brown, with variable amounts of brick 
red. The foothill yellow-legged frog is a stream-obligate species. 
Stream habitat for the species is highly variable and keyed on flow 
regimes. The current distribution of the four DPSs of the foothill 
yellow-legged frog generally follows the historical distribution of the 
species except with range contractions in the southern California Coast 
Range and southern Sierra Nevada. A map of the distribution of the four 
DPSs we are listing as well as the remainder of the species' range is 
provided in the figure below.

[[Page 59705]]

[GRAPHIC] [TIFF OMITTED] TR29AU23.000

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

[[Page 59706]]

    (E) Other natural or manmade factors affecting its continued 
existence.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the 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 the 
Service can reasonably determine that both the future threats and the 
species' responses to those threats are likely. In other words, the 
foreseeable future is the period of time in which we can make reliable 
predictions. ``Reliable'' does not mean ``certain''; it means 
sufficient to provide a reasonable degree of confidence in the 
prediction. Thus, a prediction is reliable if it is reasonable to 
depend on it when making decisions.
    It is not always possible or necessary to define foreseeable future 
as a particular number of years. Analysis of the foreseeable future 
uses the best scientific and commercial data available and should 
consider the timeframes applicable to the relevant threats and to the 
species' likely responses to those threats in view of its life-history 
characteristics. Data that are typically relevant to assessing the 
species' biological response include species-specific factors such as 
lifespan, reproductive rates or productivity, certain behaviors, and 
other demographic factors.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data regarding 
the status of the species, including an assessment of the potential 
threats to the species. The SSA report does not represent our decision 
on whether the species should be listed as an endangered or threatened 
species under the Act. However, it does 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 the viability of the four DPSs of the foothill yellow-
legged frog (North Feather, South Sierra, Central Coast, and South 
Coast), 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 each DPS to withstand 
environmental and demographic stochasticity (for example, wet or dry, 
warm or cold years), redundancy is the ability of each DPS to withstand 
catastrophic events (for example, droughts, large pollution events), 
and representation is the ability of each DPS to adapt over time to 
both near-term and long-term changes in its physical and biological 
environment (for example, climate conditions, pathogens). In general, 
DPS viability will increase with increases in resiliency, redundancy, 
and representation (Smith et al. 2018, p. 306). Using these principles, 
we identified each DPS's ecological requirements for survival and 
reproduction at the individual, population, and DPS level, and 
described the beneficial and risk factors influencing each DPS's 
viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated each individual DPS's life-history 
needs. The next stage involved an assessment of the historical and 
current condition of each DPS's demographics and habitat 
characteristics, including an explanation of how each of the DPSs 
arrived at its current condition. The final stage of the SSA involved 
making predictions about each DPS's response 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 the DPSs to sustain themselves in the wild 
over time. We use this information to inform our regulatory decisions.
    The following is a summary of the key results and conclusions from 
the SSA report; the full SSA report can be found at Docket FWS-R8-ES-
2021-0108 on https://www.regulations.gov and from the Sacramento Fish 
and Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of each of 
the four DPSs (North Feather, South Sierra, Central Coast, and South 
Coast) and their resources, and the influences on viability for each of 
the four DPS's current and future condition, in order to assess each of 
the four DPS's overall viability and the risks to that viability.
    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report, we have not 
only analyzed individual effects on each of the four DPSs, but we have 
also analyzed their potential cumulative effects. We incorporate the 
cumulative effects into our SSA analysis when we characterize the 
current and future condition of each of the four DPSs. To assess the 
current and future condition of each of the four DPSs, we undertake an 
iterative analysis that encompasses and incorporates the threats 
individually and then accumulates and evaluates the effects of all the 
factors that may be influencing each of the four DPSs, 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 each of the four DPSs in their entirety, 
our assessment integrates the cumulative effects of the factors and 
replaces a standalone cumulative effects analysis.

[[Page 59707]]

Species Needs

Stream Habitat
    The foothill yellow-legged frog is a stream-obligate species and is 
primarily observed in or along the edges of streams (Zweifel 1955, p. 
221; Kupferberg 1996a, p. 1339). Most foothill yellow-legged frogs 
breed along mainstem water channels and overwinter along smaller 
tributaries of the mainstem channel (Kupferberg 1996a, p. 1339; GANDA 
2008, p. 20). Habitat within the stream includes rocky substrate mostly 
free of sediments with interstitial spaces to allow for predator 
avoidance. Stream morphology is a strong predictor of breeding habitat 
because it creates the microhabitat conditions required for successful 
oviposition (i.e., egg-laying), hatching, growth, and metamorphosis. 
Foothill yellow-legged frogs that overwinter along tributaries often 
congregate at the same breeding locations along the mainstem each year 
(Kupferberg 1996a, p. 1334; Wheeler and Welsh 2008, p. 128). During the 
nonbreeding season, the smaller tributaries, some of which may only 
flow during the wet winter season, provide refuge while the larger 
breeding channels may experience overbank flooding and high flows 
(Kupferberg 1996a, p. 1339). Habitat elements that provide both refuge 
from winter peak flows and adequate moisture for foothill yellow-legged 
frogs include pools, springs, seeps, submerged root wads, undercut 
banks, and large boulders or debris at high-water lines (van Wagner 
1996, pp. 74-75, 111; Rombough 2006b, p. 159).
    The streams occupied by foothill yellow-legged frogs occur in a 
wide variety of vegetation types including valley-foothill hardwood, 
valley-foothill hardwood-conifer, valley-foothill riparian, ponderosa 
pine, mixed conifer, mixed chaparral, and wet meadow (Hayes et al. 
2016, p. 5). The extensive range of habitat types used by the foothill 
yellow-legged frog demonstrates the species' non-specificity in regard 
to vegetation type and macroclimate of the species' terrestrial habitat 
component. While habitat conditions can be vastly different among these 
stream sizes, and across the species' geographic range, only a narrow 
range of abiotic conditions are tolerated by early life stages (i.e., 
eggs, tadpoles, and metamorphs) (Kupferberg 1996a, p. 1336; Bondi et 
al. 2013, p. 101; Lind et al. 2016, p. 263; Catenazzi and Kupferberg 
2018, pp. 1044-1045). The abiotic conditions that directly influence 
the success of early life stages are those associated with stream 
velocity, water depth, water temperature, and streambed substrate. 
Foothill yellow-legged frogs also require stream flow regimes to have 
or mimic natural flow patterns, which includes high winter flows with a 
slowly diminishing hydrograph with increasing water temperature and 
decreasing flows into the spring and summer. Higher winter flows can 
maintain and/or increase breeding habitat by widening and diversifying 
channel morphology, improving rocky substrate conditions, and 
increasing sunlight (Lind et al. 1996, pp. 64-65; Lind et al. 2016, p. 
269; Power et al. 2016, p. 719). The reduction in flows and increasing 
water temperatures are also cues to initiate breeding. As a result, 
foothill yellow-legged frogs rely on natural, predictable changes 
during the hydrological cycle to optimize early life-stage growth and 
survival (Kupferberg 1996a, p. 1332; Bondi et al. 2013, p. 100).
Food Resources
    During their lifecycle, foothill yellow-legged frogs feed on a 
variety of plants and animals. During early development, food sources 
include algae, diatoms, and detritus that are scraped from submerged 
rocks and vegetation (Ashton et al. 1997, p. 7; Fellers 2005, p. 535). 
Juvenile and adult foothill yellow-legged frogs prey upon many types of 
aquatic and terrestrial invertebrates including snails, moths, flies, 
water striders, beetles, grasshoppers, hornets, and ants (Nussbaum et 
al. 1983, p. 165).
Migration/Dispersal Routes and Connectivity
    Adult foothill yellow-legged frogs primarily use waterway corridors 
to migrate or disperse (Bourque 2008, p. 70) and make their movements 
over multiple days (GANDA 2008, p. 22). While most foothill yellow-
legged frogs are found in, or very close to, water, juveniles and 
adults have also been observed moving through upland areas along 
intermittent drainages or in moist habitat outside of riparian 
corridors (Service 2023, section 4.8 ``Upland and Tributary 
(Nonbreeding) Habitat'', pp. 64-65). The habitat characteristics needed 
by foothill yellow-legged frogs for migration and dispersal are largely 
the same as they are for upland and tributary habitat. However, 
movement routes do not need to be moist for extended periods. Routes 
need to connect breeding areas and overwintering habitat without 
exposing frogs to large physical barriers (e.g., roads, development, 
reservoirs) or a high risk of predation. These migration and dispersal 
routes provide for metapopulation connectivity and allow for ease of 
mobility (for post-metamorphic frogs) within a metapopulation and 
between different metapopulations. Both breeding/rearing and 
overwintering sites need to be distributed across the metapopulation 
area. Foothill yellow-legged frog occupancy (i.e., presence of breeding 
adults in a given area) must also be well distributed, such that 
dispersers are able to repopulate extirpated areas of the 
metapopulation. A sufficiently resilient foothill yellow-legged frog 
metapopulation should have a network of quality breeding/rearing sites 
(often on or near the mainstem channel) and overwintering sites (often 
on tributaries of the mainstem) that are connected by habitat suitable 
for migration and dispersal (Service 2023, p. 65). An in-depth 
discussion of habitat and population elements required for the foothill 
yellow-legged frog is in the SSA report (Service 2023, chapters 4 and 
5, pp. 52-70).

Threats Influencing Current and Future Condition

    Below are summary evaluations of the threats analyzed in the SSA 
report for the foothill yellow-legged frog. The discussion focuses on 
those threats impacting the North Feather, South Sierra, Central Coast, 
and South Coast DPSs. The specific threats associated with each DPS we 
identified for listing under the Act are identified in the status 
discussion for each appropriate DPS below and in the SSA report 
(Service 2023, chapter 7, pp. 74-126).
    Those threats having the greatest impacts on the species or its 
habitat include: Altered stream hydrology and flow regimes (Factor A) 
associated with dams, surface water diversions, and channel 
modifications or alterations and their impact on the species and its 
habitat; predation and resource competition from nonnative species 
(Factor C and Factor E, respectively), such as American bullfrogs 
(Lithobates catesbeianus), smallmouth bass (Micropterus dolomieu), and 
crayfish species (Pacifastacus spp.); disease (Factor C); habitat 
degradation, loss, and fragmentation associated with wildfire (Factor 
A); the effects of climate change, including increased temperatures, 
drying and drought, and extreme flood events (Factor E); habitat 
modification and altered hydrology as a result of conservation efforts 
for salmonid species (colder water temperatures, timing and intensity 
of water flows) (Factor E); other habitat loss, degradation, and 
fragmentation (Factor A) or direct negative effects to individuals 
(Factor E) from nonnative fauna (i.e., invasive algae such as 
Didymosphenia geminata) or other

[[Page 59708]]

anthropogenic activities such as agriculture, mining, urbanization, 
roads, and recreation. Within our threat discussion, we also evaluate 
existing regulatory mechanisms (Factor D) and ongoing conservation 
measures that may ameliorate threat impacts on the four DPSs.
    Livestock grazing and timber harvest were discussed as potential 
threats and potential beneficial influences in the recent status 
assessment for the foothill yellow-legged frog in California 
(California Department of Fish and Wildlife (CDFW) 2019b, pp. 64-65, 
67). These activities were also considered in the conservation 
assessment developed by the Forest Service and BLM as part of their 
sensitive species program for the species in Oregon (Olson and Davis 
2009, pp. 18-20). While there is potential for harm to the species 
(e.g., when grazing and timber practices cause excessive erosion and 
sedimentation into streams), there are also potential positive benefits 
to foothill yellow-legged frog habitat from these practices (Olson and 
Davis 2009, pp. 18-20; CDFW 2019b, pp. 64-65, 67). We captured and 
evaluated the potential negative impacts associated with grazing and 
timber harvest (e.g., water impoundments for cattle, erosion, logging 
roads) in our assessment of altered hydrology, sedimentation, and 
roads. For full descriptions of all threats and how they impact the 
species, please see the SSA report (Service 2023, pp. 74-126).
Altered Stream Hydrology and Flow Regimes
    Foothill yellow-legged frog ecology and habitat needs are closely 
tied to the natural hydrological cycle of the streams they inhabit. 
Foothill yellow-legged frog breeding and recruitment are dependent upon 
specific stream morphologies and upon predictable hydrological patterns 
that are synchronized with other climatic cues for foothill yellow-frog 
populations to be successful (Kupferberg 1996a, p. 1337). Strong stream 
flow events typical during winter under natural flow regimes help 
maintain and create foothill yellow-legged frog breeding habitat by 
widening and diversifying channel morphology, improving rocky substrate 
conditions, removing sediment and algal growth from rocky substrate, 
and increasing sunlight by limiting vegetation encroachment (Lind et 
al. 1996, pp. 64-65; Lind et al. 2016, p. 269; Power et al. 2016, p. 
719; GANDA 2018, pp. 37-38). Dams, water management, and other waterway 
modifications alter the hydrology, timing, temperature, and morphology 
of foothill yellow-legged frog stream habitat (Service 2023, pp. 76-
80). Alterations to flow regimes also occur for hydropeaking (for 
energy production) and recreational activities, such as spring and 
summer releases for whitewater boating (Kupferberg et al. 2012, p. 518) 
(see Recreational Activities, below). These pulse flows are generally 
much greater in frequency and intensity as compared to other flow 
fluctuations and, during spring and summer, can detrimentally affect 
early life stages of foothill yellow-legged frog during breeding and 
rearing season (Greimel et al. 2018, p. 92, Kupferberg et al. 2009c, p. 
ix; Kupferberg et al. 2011b, p. 144). Therefore, alterations of stream 
hydrology and flows can have a large influence on foothill yellow-
legged frog distribution and metapopulation dynamics (Hayes et al. 
2016, pp. 24-25; Service 2023, figure 21, p. 77).
    The effects of altered streams also impede foothill yellow-legged 
frog dispersal and metapopulation connectivity, which can prevent 
recolonization of extirpated areas and cause genetic bottlenecks (Peek 
2010, p. 44; Peek 2012, p. 15). Genetic comparisons among 
subpopulations demonstrated that gene flow is decreased in regulated 
river systems, even when the amount of regulation is low (Peek 2012, p. 
15; Peek et al. 2021, p. 14).
    Many population declines across the foothill yellow-legged frog's 
range have been attributed to the altered flow regimes and habitat 
fragmentation associated with water storage and hydropower dams 
(Kupferberg et al. 2009c, p. ix). Where populations of foothill yellow-
legged frogs persist in these areas, breeding population densities were 
more than five times smaller below dams than in free-flowing rivers 
(based on breeding populations in the North Coast DPS, North Feather 
DPS, and Central Coast DPS) (Kupferberg et al. 2012, p. 520). Dams and 
impoundments have also presumably caused localized extirpations of the 
species and altered stream characteristics in some locations (Miller 
2010, pp. 14, 61-63, 70-71, table 2.9; Linnell and Davis 2021, not 
paginated, figures 6 and 7).
    Some measures have been implemented to reduce the threat of altered 
flow regimes on regulated streams. In 2001, the Federal Energy 
Regulatory Commission (FERC) issued an order to the licensee 
responsible for flow regulation on the Cresta and Poe reaches of the 
North Feather River (Rock Creek-Cresta Hydroelectric Project (FERC 
Project No. 1962) Pacific Gas and Electric Company (PG&E)). The order 
requires PG&E to develop a plan to ensure recreational and pulse flow 
releases do not negatively impact the foothill yellow-legged frog. The 
order also requires the establishment of an Ecological Resources 
Committee (ERC) to evaluate effects of flows and provide adaptive 
management strategies if flows had a negative impact on the foothill 
yellow-legged frog populations within the two reaches. In 2006, flow 
releases for recreational boating were discontinued on the Cresta reach 
due to possible impacts from flows resulting in low foothill yellow-
legged frog egg masses that year. In 2009 and again in 2014, modified 
flow programs were implemented to mimic natural flow regimes by 
reducing flows in spring and summer (April through the foothill yellow-
legged frog's breeding season) (GANDA 2018, pp. 1-2). We expect these 
measures to continue in accordance with the adaptive management 
strategies implemented under the ERC based on ongoing monitoring of the 
two reaches. As a result, there are some signs of improved abundance 
since 2018 in at least the Cresta reach of the North Feather River 
following the above-described modifications of the regulated flow 
regime to more natural conditions.
    Altered flow regimes and water diversions (as well as several 
anthropogenic activities, such as mining, agriculture, overgrazing, 
timber harvest, and poorly constructed roads), as described in greater 
detail below, can cause or increase sedimentation in breeding habitat 
for the foothill yellow-legged frog (Moyle and Randall 1998, pp. 1324-
1325). Increased sedimentation can increase turbidity, impact algae and 
other food resources, or impede foothill yellow-legged frog egg mass 
attachment to substrate (Cordone and Kelley 1961, pp. 191-192; Ashton 
et al. 1997, p. 13). Fine sediments can also fill interstitial spaces 
between rocks, which provide shelter from high velocity flows, cover 
from predators, and sources of aquatic invertebrate prey (Harvey and 
Lisle 1998, pp. 12-14; Olson and Davis 2009, p. 11; Kupferberg et al. 
2011b, pp. 147-149). The nonnative algae (Didymosphenia geminata) has 
also been associated with areas below dams and causes impacts to food 
resources and alters habitat conditions by forming thick algal mats on 
rocky substrate within foothill yellow-legged frog habitat (Spaulding 
and Elwell 2007, entire; Furey et al. 2014, pp. 8-10).
Predation
    Foothill yellow-legged frogs can be negatively affected by several 
native and

[[Page 59709]]

nonnative animal species. The American bullfrog, native and nonnative 
fish, and nonnative crayfish have all been linked to impacting 
populations of foothill yellow-legged frogs (Olson and Davis 2009, pp. 
17-18; Hayes et al. 2016, pp. 49-51). The following discussion provides 
details on how these predatory species affect the foothill yellow-
legged frog at various life stages through predation and competition.
    American bullfrogs: American bullfrogs are considered a threat to 
all four DPSs. Bullfrogs affect foothill yellow-legged frog populations 
in several ways because they are simultaneously competitors, predators, 
and disease vectors, and they impact life stages from tadpoles to 
adults (see figure 23 in the SSA report, Service 2023, p. 81). 
Bullfrogs impact foothill yellow-legged frogs by direct predation 
(Crayon 1998, p. 232; Hothem et al. 2009, pp. 279-280) and indirectly 
by reducing survival. In one experiment, the presence of bullfrog 
tadpoles reduced foothill yellow-legged frog tadpole survival by 48 
percent and mass at metamorphosis by 24 percent (Kupferberg 1997, p. 
1736). Additionally, the algal and macroinvertebrate assemblages 
available to foothill yellow-legged frogs were significantly reduced 
due to the presence of bullfrog tadpoles (Kupferberg 1996b, p. 2; 
Kupferberg 1997, p. 1736), which would negatively affect food sources 
for foothill yellow-legged frog tadpoles, juveniles, and adults. The 
spread of bullfrogs is facilitated by altered hydrology, land-use 
change, drought, and increasing water temperatures (Moyle 1973, p. 21; 
Fuller et al. 2011, pp. 210-211; Adams et al. 2017a, p. 13).
    Fish: Fish such as smallmouth bass, green sunfish (Lepomis 
cyanellus), mosquitofish (Gambusia affinis), and trout (Oncorhynchus, 
Salmo, and Salvelinus spp.) are predators of foothill yellow-legged 
frogs and may also potentially compete with them for invertebrate food 
resources (Hayes et al. 2016, p. 51). However, of these fish, 
smallmouth bass are the greatest threat to foothill yellow-legged 
frogs. Adult smallmouth bass consume amphibian tadpoles (Kiesecker and 
Blaustein 1998, pp. 776-787), as well as foothill yellow-legged frog 
tadpoles and adults (Rombough 2006a, unpaginated; Paoletti et al. 2011, 
p. 166). The distribution of smallmouth bass in California includes the 
entire South Coast DPS, lower elevation areas of the South Sierra and 
North Feather DPSs in the Central and Sacramento Valleys, and areas in 
the Central Coast DPS's range in the Salinas and Santa Clara Valleys.
    Nonnative crayfish: Several nonnative crayfish species prey upon 
early life stages of foothill yellow-legged frog. The signal crayfish 
(Pacifastacus leniusculus) has been introduced into several areas 
within the coast ranges of northern California and the Sierra Nevada 
(Wiseman et al. 2005, p. 162; Pintor et al. 2009, p. 582; CDFW 2019b, 
p. 56). The signal crayfish preys upon foothill yellow-legged frog egg 
masses, and likely contributes to dislodging egg masses from substrate, 
potentially allowing them to be transported to unsuitable habitat 
(Rombough and Hayes 2005, p. 163; Wiseman et al. 2005, p. 162). Signal 
crayfish also prey on foothill yellow-legged frog tadpoles in 
laboratory settings (Kerby and Sih 2015, p. 266), and observations of 
tail injuries in wild tadpoles suggest crayfish predation also occurs 
in the wild (Rombough and Hayes 2005, p. 163; Wiseman et al. 2005, p. 
162).
Disease
    Foothill yellow-legged frogs can be negatively affected by 
amphibian chytrid fungus (Batrachochytrium dendrobatidis (Bd)), 
parasitic copepods, and Saprolegnia fungus (see figure 24 in the SSA 
report, Service 2023, p. 84).
    Bd is implicated in the declines or presumed extinctions of 
hundreds of amphibian species (Scheele et al. 2019, p. 1). The spread 
of Bd in the range of the foothill yellow-legged frog is presumably 
linked to increased human use of habitat and the introduction of 
nonnative bullfrogs, which are Bd reservoir hosts (Huss et al. 2013, p. 
341; Adams et al. 2017b, pp. 10225-10226; Yap et al. 2018, pp. 1-2; 
Byrne et al. 2019, p. 20386). The southern California precipitation 
regime (i.e., alternation of extreme droughts and floods) may increase 
the likelihood of disease outbreaks by causing favorable habitat 
conditions for bullfrogs, warmer water temperatures, and increased 
stress on foothill yellow-legged frogs (Adams et al. 2017b, p. 10228). 
Bullfrog presence is a positive predictor of Bd prevalence and load in 
foothill yellow-legged frogs (Adams et al. 2017a, p. 1). The Bd 
pathogen has been documented within all four DPSs (Yap et al. 2018, p. 
5, figure 1), and evidence of Bd prevalence suggests that Bd played a 
role in the precipitous decline of the foothill yellow-legged frog in 
southern California. Bd has been implicated in the decline of the 
foothill yellow-legged frog in both the Central Coast DPS and South 
Coast DPS (Adams et al. 2017b, p. 10224). Bd may also have sublethal 
effects on foothill yellow-legged frogs. Foothill yellow-legged frogs 
that tested positive for Bd had lower body mass to length ratios, 
although the frogs showed no other signs of infection (Lowe 2009, pp. 
180-181). Tadpole susceptibility experiments with other western anurans 
documented species-specific effects of Bd exposure such as tadpole 
lethargy (motionless at bottom of tank), disorientation, weak response 
to prodding, and increased incidence of tadpole mouthpart deformities 
(Blaustein et al. 2005, pp. 1464-1466).
    Parasitism of foothill yellow-legged frogs by the Eurasian copepod, 
Lernaea cyprinacea, is linked to malformations in tadpole and juvenile 
foothill yellow-legged frogs (Kupferberg et al. 2009a, p. 529). In 
addition to malformations, this parasite likely has other sublethal 
effects on foothill yellow-legged frogs, such as stunted growth 
(Kupferberg et al. 2009a, p. 529). Although direct foothill yellow-
legged frog mortality from this parasite has not been documented in the 
wild, copepod parasitism may be responsible for mortality of tadpoles 
in captivity (Kupferberg 2019, entire; Oakland Zoo 2019, p. 1; Rousser 
2019, entire). The changes predicted by climate change models (i.e., 
increased summer water temperatures and decreased daily discharge) may 
promote outbreaks of this parasite throughout the foothill yellow-
legged frog's range (Kupferberg et al. 2009a, p. 529).
    The water fungus (Saprolegnia sp.) causes egg mortality in 
amphibians of the Pacific Northwest (Blaustein et al. 1994, p. 251). 
Fungal infections of foothill yellow-legged frog egg masses, 
potentially from Saprolegnia but not confirmed, have been observed in 
the mainstem Trinity River (North Coast DPS) (Ashton et al. 1997, pp. 
13-14), in approximately 25 percent of egg masses during a study in the 
South Fork Eel River (North Coast DPS) (Kupferberg 1996a, p. 1337), and 
in 14 percent of egg masses during 2002 and nearly 50 percent of egg 
masses during 2003 in the Cresta reach of the North Fork Feather River 
(North Feather DPS) (GANDA 2004, p. 55). While fungal infections are 
not a major source of mortality for foothill yellow-legged frogs, this 
threat has had a strong effect in other amphibian populations 
(Blaustein et al. 1994, pp. 251-253).
Habitat Loss, Degradation, and Fragmentation
    Habitat loss, degradation, and fragmentation occurs throughout the 
species' range and is attributed to numerous factors including 
agricultural activities, mining, urbanization, roads, recreation, and 
wildfire.

[[Page 59710]]

    Agriculture/Pesticides: Agriculture is a source of threats to the 
foothill yellow-legged frog because of agriculture's role in habitat 
degradation, the contribution of pesticides and pollutants to the 
environment, and its role as a driver of other threats such as altered 
hydrology and spread of nonnative species (see figure 26 in the SSA 
report, Service 2023, p. 89). Agricultural land uses have been linked 
to declines in foothill yellow-legged frog populations due to the 
impacts described above (Davidson et al. 2002, p. 1597; Lind 2005, pp. 
19, 51, 62, table 2.2; CDFW 2019b, p. 58). Foothill yellow-legged frog 
presence is negatively associated with agriculture within 5 kilometers 
(km) (3.1 miles (mi)) (Olson and Davis 2009, pp. 15, 22; Linnell and 
Davis 2021, not paginated, figures 6 and 7).
    The proximity of foothill yellow-legged frog habitat downwind of 
the San Joaquin Valley (greatest use of airborne pesticides) suggests 
that foothill yellow-legged frog declines in the South Sierra unit may 
be linked to agricultural pesticide use (Davidson et al. 2002, p. 1594; 
Davidson 2004, pp. 1900-1901; Bradford et al. 2011, p. 690). Water 
samples from low elevations in the Sierra Nevada have had 
concentrations of pesticides that were within the lethal range for 
foothill yellow-legged frogs (Bradford et al. 2011, p. 690). Foothill 
yellow-legged frog tadpoles are especially vulnerable to pesticides, 
especially if pesticide exposure occurs in the presence of other 
threats, such as competition or predation (Davidson et al. 2007, 
entire; Sparling and Fellers 2007, entire; Sparling and Fellers 2009, 
entire; Kerby and Sih 2015, entire). Impacts from pesticides include 
reduced body size, slower development rate, and increased time to 
metamorphosis, as well as decreased development of natural anti-
microbial skin peptides (presumably a defense against the disease, 
chytridiomycosis) (Davidson et al. 2007, p. 1774; Sparling and Fellers 
2009, pp. 1698, 1701; Kerby and Sih 2015, pp. 255, 260).
    Trespass Cannabis Cultivation: Trespass cannabis cultivation 
(illegally establishing largescale cannabis farms) occurs throughout 
the species' range, but the Central Coast and South Coast DPSs may be 
most at risk from this threat (CDFW 2019b, pp. 61-62). These 
unregulated activities impact the foothill yellow-legged frog by 
destroying or degrading habitat, increasing water diversion, increasing 
sedimentation, and introducing pesticides and other chemicals that 
reduce water quality and impact the species (Bauer et al. 2015, entire; 
National Marijuana Initiative 2020, pp. 50-60, 68-75).
    Mining Activities: Mining activities, including aggregate, hard-
rock, and suction-dredge mining, are sources of threats to the foothill 
yellow-legged frog habitat because of their role in habitat destruction 
and degradation, pollution, and expansion of nonnative species (Hayes 
et al. 2016, pp. 52-54; Service 2023, figure 29, p. 96). Hydraulic 
mining, although outlawed, has had and continues to have long-lasting 
legacy effects and is still affecting aquatic ecosystems in California, 
with the North Feather DPS being the most impacted (Hayes et al. 2016, 
pp. 52-54; CDFW 2019b, pp. 57-58). The immediate and legacy effects and 
extent of mining practices are outlined in table 8 of the SSA report 
(Service 2023, pp. 93-96), and include habitat destruction and 
alteration, sedimentation, changes in stream morphology, decreased 
stream heterogeneity, creation of ponded habitat (that supports 
nonnative species), decreased water quality, and contamination. A 
moratorium of suction-dredging in streams is currently in place for 
California. However, the State is currently developing new guidance and 
permitting processes for potentially reinitiating suction-dredging 
activities (State Water Resources Control Board 2020, entire).
    Urbanization: Urbanization (development and roads) can affect 
foothill yellow-legged frogs and their habitat through direct mortality 
and from habitat destruction, degradation, and fragmentation. 
Urbanization can also contribute to increased occurrence of pesticides 
and pollutants being introduced to the environment, contribute to 
increases in other threats such as altered hydrology and introduction 
and spread of nonnative species, and assist in disease transmission 
(see figure 30 in the SSA report, Service 2023, p. 97). Conversion or 
alteration of natural habitats for urban land uses has been linked to 
declines in foothill yellow-legged frog populations (Davidson et al. 
2002, p. 1597; Lind 2005, pp. 19, 51, 62, table 2.2). Foothill yellow-
legged frog presence is negatively associated with cities and road 
density (Davidson et al. 2002, p. 1594; Olson and Davis 2009, p. 22). 
Increases in urbanization and roads have been reportedly associated 
with foothill yellow-legged frog extirpations in the South Coast DPS, 
possibly by facilitating the spread of Bd and nonnative species (Adams 
et al. 2017b, p. 10227).
    Recreational Activities: Some recreational activities can affect 
foothill yellow-legged frogs in a variety of ways, depending on the 
region and type of recreation. Impacts from recreation can be 
localized, such as trampling or dislodging of egg masses, while others 
are greater in extent or contribute to other threats. These greater 
threats include off-highway vehicle use causing habitat degradation and 
increased sedimentation (Olson and Davis 2009, p. 23), nonnative 
sportfish stocking of smallmouth bass (see ``Predation,'' above) (CDFW 
2019a, entire), and altered hydrology due to whitewater boating 
(Borisenko and Hayes 1999, pp. 18, 28; Kupferberg et al. 2012, p. 518). 
Some dam operations include planned, short pulse flows during the 
spring and summer to specifically provide recreation opportunities for 
whitewater boaters (Kupferberg et al. 2012, p. 518). As with other 
impacts associated with water management, the timing of these strong 
unseasonal flows has coincided with the foothill yellow-legged frog 
breeding and rearing season, leading to negative population-level 
impacts in the North Feather DPS (Kupferberg et al. 2012, pp. 518, 520-
521, figure 3b).
    Wildfire: Wildfire is a natural phenomenon throughout the range of 
the foothill yellow-legged frog, and its occurrence and severity are 
positively influenced by urbanization, roads, recreation, and the 
effects of climate change. The effects on foothill yellow-legged frogs 
from wildfire and its suppression are not well understood and have not 
been directly studied (Hayes et al. 2016, p. 35, table 6; CDFW 2019b, 
p. 71). The impacts of wildfire are also a function of the severity and 
intensity of the wildfire, which can be extremely variable across the 
landscape depending on topography and vegetation. Anecdotally, foothill 
yellow-legged frog populations have survived low- to moderate-severity 
wildfires (Lind et al. 2003, p. 27; CDFW 2019b, p. 71), and it is 
suspected that low-severity fires do not have adverse effects on the 
foothill yellow-legged frog (Olson and Davis 2009, p. 24). In fact, 
wildfires may benefit habitat quality by decreasing canopy cover and 
increasing habitat heterogeneity (Pilliod et al. 2003, pp. 171, 173; 
Olson and Davis 2009, p. 24). Direct mortality from scorching is 
unlikely, given the species' aquatic nature and the sightings of 
foothill yellow-legged frogs immediately after wildfires (CDFW 2019b, 
p. 71). In contrast, high-severity wildfires can greatly alter water 
and habitat quality, remove all vegetative canopy, and reduce habitat 
heterogeneity by burning vegetative and woody debris that foothill 
yellow-legged frogs use for shelter. Short- and long-term effects of 
severe wildfires include potentially harmful changes in water chemistry 
and

[[Page 59711]]

increased erosion and sedimentation from flooding (CDFW 2019b, pp. 71-
72), which can destroy or degrade breeding habitat and interstitial 
spaces. Furthermore, the use of fire retardants and suppressants during 
wildland firefighting can affect amphibians by harming water quality 
and by direct toxicity to amphibians and their food sources (Pilliod et 
al. 2003, pp. 174-175; Service 2018, pp. 42-44). See the SSA report for 
additional information regarding trends and impacts of wildfire 
(Service 2023, section 7.9, pp. 103-113).
Effects of Climate Change
    The effects of climate change are already having impacts in the 
areas occupied by the four DPSs in California (Bedsworth et al. 2018, 
p. 13; Mote et al. 2019, p. ii, summary). Overall trends in climate 
conditions across the foothill yellow-legged frog's range include 
increasing temperatures; greater proportion of precipitation falling as 
rain instead of snow; earlier snowmelt (influencing streamflow); and 
increased frequency, duration, and severity of extreme events such as 
droughts, heat waves, wildfires, and floods (Public Policy Institute of 
California 2020, not paginated). A rangewide study of occupancy found 
that foothill yellow-legged frog presence is negatively related to the 
frequency of dry years and to precipitation variability, suggesting 
that the species may already be declining due to the effects from 
climate change (Lind 2005, p. 20).
    Projected increases in temperature are likely to affect foothill 
yellow-legged frogs differently in different parts of the range. 
Warming temperatures are likely to have some positive effects in areas 
where stream temperatures are typically colder, allowing for greater 
foothill yellow-legged frog population growth rates and early life 
stage survival (Kupferberg et al. 2011a, p. 72; Rose et al. 2020, p. 
41). However, researchers observed an unexpected die-off (unknown 
cause) of late-stage tadpoles that coincided with maximum daily 
temperatures exceeding 25 degrees Celsius ([deg]C) (77 degrees 
Fahrenheit ([deg]F)) (Kupferberg et al. 2011a, pp. 14, 58; Catenazzi 
and Kupferberg 2018, pp. 43-44, figure 2). Temperatures greater than 
the preferred thermal range may also have lethal or sublethal effects 
on tadpoles and metamorphs from parasites (Kupferberg et al. 2009a, p. 
529; Kupferberg et al. 2011a, p. 15). There may be additional negative 
consequences to rising stream temperatures, even where temperatures are 
currently cold. Increasing temperatures may facilitate colonization by 
nonnative species (Fuller et al. 2011, pp. 210-211; Kiernan et al. 
2012, pp. 1480-1481). Bd prevalence in bullfrogs was also found to be 
greater when water temperature was warmer than 17 [deg]C (63 [deg]F) 
(Adams et al. 2017a, pp. 12-13).
    In California, a 25 to 100 percent increase in the frequency of 
extreme dry-to-wet precipitation events (such as that of the 2012-2016 
drought followed by the extremely wet winter of 2016-2017) is projected 
during the 21st century (Swain et al. 2018, p. 427). This information 
indicates that the threats of drought and extreme flood events may 
increase by 25 to 100 percent in California. In order to assess future 
conditions, including future climatic conditions for the foothill 
yellow-legged frog, we developed a population viability analysis (PVA) 
(Rose et al. 2020, entire) that used climate and habitat change 
information consistent with current emission estimates such as those 
identified as representative concentration pathway (RCP) 4.5 and RCP 
8.5 (see ``Population Viability Analysis,'' below).
    The projected changes in temperature, precipitation, and climate 
variability may exacerbate the effects of other threats on the foothill 
yellow-legged frog (Service 2023, figure 46, p. 120). The potential 
interactions (between climate change effects and other threats) that 
can negatively affect the foothill yellow-legged frog include:
     An increased risk to human safety from flooding and 
increased risk of water shortages may necessitate more hydrological 
alterations (e.g., dams, surface-water diversions, changes to water 
releases, and channel modifications). By mid-century, the projected 
increases in watersheds experiencing climate-induced water stress in 
California ranges from 5 to 30 percent, with the South Sierra DPS 
experiencing the greatest amount of change (Averyt et al. 2013, p. 7, 
figure 7).
     Increased frequency of drought, decreased spring/summer 
streamflow, and warmer water temperature may benefit nonnative 
predators and competitors such as bullfrogs and nonnative fish (Brown 
and Ford 2002, pp. 332, 338-340, figure 3; Fuller et al. 2011, pp. 210-
211; Adams et al. 2017a, p. 13).
     Increased summer water temperatures and/or decreased daily 
stream discharge and other increases in climate variability are 
expected to increase copepod parasitism in foothill yellow-legged frogs 
(Kupferberg et al. 2009a, p. 529) or exacerbate the effects of disease 
outbreaks (Raffel et al. 2013, p. 147; Adams et al. 2017b, p. 10228).
     Observed and projected trends toward warmer and drier 
wildfire seasons in the western United States are likely to continue 
the trend toward higher-severity wildfires and larger burn areas (Parks 
and Abatzoglou 2020, pp. 1, 5-6). This would result in additional loss, 
degradation, fragmentation, and alteration of habitat, and secondary 
impacts from increased sedimentation and flooding for the foothill 
yellow-legged frog across its range.
Competing Conservation Interests
    Many of the conservation activities that support native salmonid 
fishes (e.g., natural flow management, prevention of sedimentation) 
have positive influences on foothill yellow-legged frog habitat, 
connectivity, and juvenile and adult survival (Service 2023, section 
7.12, figure 45, p. 117). However, some measures that are taken to 
improve habitat for cold-water salmonid fishes reduce habitat quality 
for the foothill yellow-legged frog by decreasing stream temperature 
and increasing tree canopy cover over streams which negatively 
influence breeding conditions (such as delaying breeding cues or 
shortening breeding season) and potentially slow maturation rates for 
tadpoles. One of the management techniques used to support salmonid 
recruitment is to release high volumes of cold water from dams in the 
spring (to trigger spawning runs or to flush smolts out to the ocean) 
(Kupferberg 1996a, p. 1342; Kiernan et al. 2012, p. 1474). The timing 
of such flow events can negatively affect foothill yellow-legged frog 
breeding and recruitment (Kupferberg 1996a, pp. 1336-1337, 1342).

Current and Future Condition Analysis

    In our analysis of the current and future condition, we assessed 
resiliency for each of the four DPSs of the foothill yellow-legged frog 
by evaluating the health and number of metapopulations for each DPS. A 
healthy metapopulation is defined in terms of its abundance, level of 
reproduction and recruitment, juvenile and adult survival, and 
connectivity between populations. To assess the current representation 
for the foothill yellow-legged frog, we considered the current 
diversity of ecological conditions and the genetic makeup of each DPS 
as a proxy for the DPS's adaptive capacity. Redundancy for the foothill 
yellow-legged frog was measured by the quantity and spatial 
distribution of metapopulations that have been identified as having 
sufficient resiliency (based on breeding information) across each DPS's 
range. Generally speaking, the greater the number of healthy 
metapopulations that

[[Page 59712]]

are distributed (and connected) across the landscape, the greater the 
DPS's ability to withstand catastrophic events and, thus, the greater 
the DPS's overall viability.
Population Structure
    Foothill yellow-legged frog distributions and movements across the 
species' range and within each DPS exhibit the characteristics of 
metapopulations (Lind 2005, p. 49; Kupferberg et al. 2009b, p. 132). A 
metapopulation consists of a network of spatially separated population 
units, or subpopulations, that interact at some level. Subpopulations 
are subject to periodic extirpation from demographic or environmental 
stochasticity, but then are naturally repopulated via colonization from 
nearby subpopulations. Numerous metapopulations may occur within a 
single stream reach or watershed depending on whether the 
subpopulations are interacting with each other. Each DPS is made up of 
numerous metapopulations. In our analysis for determining the range of 
each DPS, we considered this metapopulation structure when determining 
whether certain populations or segments interacted with each other and 
helped define boundaries for the DPSs, especially where some other 
natural or manmade barrier was not evident.
Current Distribution, Occupancy, Abundance, and Population Trends
    The current distribution of the foothill yellow-legged frog 
generally follows its historical distribution (see the SSA report 
(Service 2023, pp. 15-19) and December 28, 2021, proposed rule (see 86 
FR 73926-73927) for discussion of the historical distribution of the 
foothill yellow-legged frog) except with range contractions in the 
southern and, to a lesser extent, northern parts of the species' range. 
Within areas currently occupied, foothill yellow-legged frog 
distribution is currently in a declining trend in several parts of the 
species' range with the species having disappeared from more than half 
of its historically occupied locations (Lind 2005, pp. 38, 61, table 
2.1).
    There has not been any rangewide occupancy or population abundance 
survey effort for the species, and some areas are more heavily surveyed 
than others. Because of this variation in the available data, we use 
presence in stream segments as an indicator of occupancy and spatial 
connectivity of populations. In our review of occupancy, distribution, 
and abundance, we used information from the California Natural 
Diversity Database (CNDDB) (CDFW 2020, foothill yellow-legged frog 
information) and other survey information obtained from Federal and 
other academic and private resource entities throughout the species' 
range. The factors we analyzed to determine the condition of a 
population are (1) spatial and temporal trends in occupancy and reports 
of population abundance where available, (2) connectivity and isolation 
among occupied areas, (3) modeled risk of population decline that 
incorporates demographic and environmental information, and (4) status 
of threats and their effects (see chapter 8 of the SSA report, Service 
2023, pp. 127-172).
    Foothill yellow-legged frog occupancy varies widely, with generally 
greater occupancy in the northern half of the range. Proportions of 
presumed occupied stream segments were lowest in the South Coast DPS, 
followed by the South Sierra DPS, Central Coast DPS, and North Feather 
DPS (see table 10 in the SSA report, Service 2023, p. 130).
    Based on current occurrence data (Element Occurrences) for 
California (CDFW 2020, entire) from the time period between 2000-2020, 
70 percent of all known occurrence locations are presumed to be 
occupied by the foothill yellow-legged frog in the North Feather DPS 
(Service 2023, table 10, p. 130). However, looking at a more recent 
timeframe (2010-2020) the occupancy of foothill yellow-legged frogs in 
the North Feather DPS's range has been reduced to 42 percent (Service 
2023, table 10, figure 49, pp. 130, 137). In the South Sierra DPS the 
number of occupied locations is 43 percent, the Central Coast DPS is 42 
percent, and the South Coast DPS is 8 percent (Service 2023, table 10, 
p. 130). Based on patterns of current occupancy by decade of most 
recent detections (Service 2023, figures 47-53, pp. 133-145), occupied 
areas are declining in parts of each of the four DPSs. There are large 
regions in the South Sierra DPS, Central Coast DPS, and South Coast DPS 
that have not had any reported observations of foothill yellow-legged 
frogs for two or more decades. Foothill yellow-legged frogs are mostly 
extirpated in the South Coast DPS and currently occur only in two 
streams.
Population Viability Analysis
    In addition to our assessments of occupancy, abundance, and trends, 
using occurrence information, we worked with USGS researchers to 
complete a rangewide population viability analysis (PVA) for the 
foothill yellow-legged frog (Rose et al. 2020, entire). We used the 
information from the PVA to inform both the species' current condition 
(Service 2023, chapter 8, pp. 127-172) and potential future condition 
(Service 2023, chapter 9, pp. 173-199). The methods and information 
used for developing the models used in the PVA are described in section 
8.4 of the SSA report (Service 2023, pp. 152-159). The results of the 
PVA focus on identifying patterns in risk attributed to areas having a 
greater than or equal to 50 percent decline within and between DPSs 
(analysis units) and characterize this as the ``risk of decline.''
    The ``risk of decline'' results from the PVA reflect many of the 
geographical patterns that we described above for occupancy data 
(Service 2023, section 8.2, pp. 128-145). A summary of the PVA results 
for the current condition of foothill yellow-legged frog populations 
within the boundaries of the four DPSs combined with our analysis of 
occupancy information is discussed below.
    The North Feather DPS has a medium-high average relative risk of 
decline and an intermediate proportion of occupied stream segments 
(relative to potential stream segments). The southern DPSs (Central 
Coast, South Coast, and South Sierra DPSs) exhibit the strongest 
patterns of declining occupancy, with all stream segments within each 
DPS having either a medium or high relative risk of decline.
    Chapter 9 of the SSA report (Service 2023, pp. 173-199) discusses 
the potential change in magnitude and extent of threats and the 
species' response to those threats into the future. We have determined 
that the effects of climate change and its impact on increasing 
temperatures, changes to precipitation and hydrology, and influence on 
wildfire and drought, as well as the continued regulated flows from 
managed streams, will affect its status into the future. The timeframe 
of our analysis for these threats is approximately 40 years. This 
period represents our best understanding of the projected future 
environmental conditions related to threats associated with climate 
change that would impact the species (increasing temperatures; greater 
proportion of precipitation falling as rain instead of snow; earlier 
snowmelt (influencing streamflow); and increased frequency, duration, 
and severity of extreme events such as droughts, heat waves, wildfires, 
and floods). The 40-year timeframe was also used in our PVA as part of 
its analysis on determining risk for the species into the future (Rose 
et al. 2020, entire). Although we possess climate and habitat change 
projections that go out beyond 40 years, there is greater

[[Page 59713]]

uncertainty between these model projections in the latter half of the 
21st century and how the effects of the modeled changes will affect the 
species' response when projected past 40 years. Accordingly, we 
determined that the foreseeable future extends only 40 years for the 
purpose of this analysis, and we rely upon projections out to 
approximately 2060 for predicting changes in the species' conditions. 
This timeframe allows us to be more confident in assessing the impact 
of climate and habitat changes on the species. Therefore, based on the 
available climate and modeling projections and information we have on 
the species, we have determined 2060 as the foreseeable future 
timeframe for the foothill yellow-legged frog.
    Our assessment of future condition interprets the effects that the 
future changes to threats would potentially have on foothill yellow-
legged frog resiliency, representation, and redundancy. In order to 
accomplish our review, three plausible future scenarios were considered 
and each DPS's future resiliency, redundancy, and representation under 
each scenario was assessed. As discussed above, we used information 
from a PVA (Rose et al. 2020, pp. 22-27) to assist us in determining 
the potential condition of foothill yellow-frog populations into the 
future. Although there are an infinite number of possible future 
scenarios, the chosen scenarios (i.e., lower change scenario, mean 
change scenario, and higher change scenario) reflect a range of 
reasonable scenarios based on the current understanding of climate 
change models, threats, and foothill yellow-legged frog ecology. The 
environmental conditions in each future scenario are plausible in that 
they are not meant to represent the lowest and highest projections of 
what is possible. Rather, the lower change and higher change scenarios 
are at the lower and upper ends of confidence intervals from climate 
change projections, land cover models, and stream temperature models 
(Rose et al. 2020, pp. 22-23). Environmental conditions for the three 
future scenarios are based on published studies that used ensembles of 
global climate models (Isaak et al. 2017, p. 9188; Swain et al. 2018, 
p. 427; Sleeter et al. 2019, p. 3336). For the projections of spatially 
explicit covariates (i.e., land cover and stream temperature), 
downscaled regional climate model data were used (Isaak et al. 2017, p. 
9186; Sleeter et al. 2019, p. 3339). The information from these studies 
reflects the best scientific and commercial information available for 
projections of land cover (Sleeter et al. 2019; Sleeter and Kreitler 
2020, unpublished data), stream temperature (Isaak et al. 2017), and 
climate variability (Swain et al. 2018) within the range of the 
foothill yellow-legged frog.
    Descriptions of each scenario and the anticipated effects of each 
scenario on resiliency, representation, and redundancy for each 
foothill yellow-legged frog DPS are provided in the SSA report (Service 
2023, table 17, sections 9.3-9.5, pp. 177, 180-199) and are summarized 
below.
Resiliency
    Resiliency is the ability of a species (or DPS) to sustain 
populations through the natural range of favorable and unfavorable 
conditions. For the foothill yellow-legged frog, we determined that 
resiliency is a function of metapopulation health and the distribution 
and connectivity among metapopulations and subpopulations. To determine 
if foothill yellow-legged frog populations are sufficiently resilient, 
we first assessed spatial and temporal trends in occupancy and 
abundance. We then assessed structural and functional connectivity 
among occupied areas. We also evaluated results from a study that 
modeled the risk of greater than or equal to 50 percent decline in 
occupied stream segments using demographic and environmental 
information. Finally, we related our results to information from 
scientific literature, reports, and species experts. The table below 
summarizes the current condition and future conditions of resiliency 
for each of the four foothill yellow-legged frog DPSs. The current 
condition column reflects the current resiliency of the DPS. The 
current resiliency of each of the four DPSs was characterized as having 
an intact, reduced, substantially reduced, or extensively reduced 
condition. Under each future scenario, we assessed how the following 
resiliency measures would change from current condition: (1) occupancy 
and abundance, (2) connectivity, (3) modeled risk of population 
decline, and (4) status of threats. Because changes to environmental 
conditions under the future scenarios were reflected by environmental 
covariates in the PVA (see Service 2023, section 9.2 (Scenarios) and 
table 17), we were able to forecast the magnitudes of changes in 
resiliency by comparing the modeled risk of decline (Rose et al. 2020, 
entire) under current conditions to modeled risk under the three future 
scenarios. The lower, mean, and higher change scenario columns 
represent any changes from each DPS's current resiliency. For this 
analysis, ``functional extirpation'' is defined as such extensive 
reduction in condition that extirpation of the entire unit is likely to 
eventually occur as remnant populations experience normal environmental 
and demographic fluctuations. For additional details on current and 
future conditions of the DPSs, see the SSA report (Service 2023, 
chapters 8 and 9, pp. 127-199).

                         Table--Resiliency of the Four Foothill Yellow-Legged Frog DPSs
----------------------------------------------------------------------------------------------------------------
                                                         Lower change         Mean change        Higher change
   Distinct population segment     Current condition       scenario            scenario            scenario
----------------------------------------------------------------------------------------------------------------
North Feather DPS...............  Reduced resiliency  No change.........  Markedly reduced    Greatly reduced
                                                                           from current.       from current.
                                                                          Risk of functional  Risk of functional
                                                                           extirpation.        extirpation or
                                                                                               extirpation.
South Sierra DPS................  Substantially       Slightly reduced    Markedly reduced    Greatly reduced
                                   reduced             from current.       from current.       from current.
                                   resiliency.
                                                                          Risk of functional  Risk of functional
                                                                           extirpation or      extirpation or
                                                                           extirpation.        extirpation.
Central Coast DPS...............  Substantially       Slightly reduced    Markedly reduced    Greatly reduced
                                   reduced             from current.       from current.       from current.
                                   resiliency.
                                                                          Risk of functional  Risk of functional
                                                                           extirpation or      extirpation or
                                                                           extirpation.        extirpation.
South Coast DPS.................  Extensively         Slightly reduced    Markedly reduced    Greatly reduced
                                   reduced             from current.       from current.       from current.
                                   resiliency.

[[Page 59714]]

 
                                                      Risk of             Risk of             Risk of
                                                       extirpation.        extirpation.        extirpation.
----------------------------------------------------------------------------------------------------------------

Representation
    Representation describes the ability of a species or DPS to adapt 
to changing environmental conditions. This includes both near-term and 
long-term changes in its physical (e.g., climate conditions, habitat 
conditions, habitat structure, etc.) and biological (e.g., pathogens, 
competitors, predators, etc.) environments. This ability of a species 
or DPS to adapt to these changes is often referred to as ``adaptive 
capacity.'' To assess the current condition of representation for the 
four DPSs of the foothill yellow-legged frog, we considered the current 
diversity of ecological conditions and of genetic material throughout 
the range of each of the DPSs.
    There are considerable ranges of ecological conditions under which 
the four DPSs occur. As discussed in the SSA report (Service 2023, pp. 
23, 37-51), there are substantial differences in latitude, elevation, 
precipitation, average temperature, and vegetative community across the 
areas occupied by the four DPSs' ranges. The areas occupied by the four 
DPSs also differ in terms of species composition and in hydrology 
(rain-fed versus snow-fed systems). Exemplary of these different 
ecological conditions, foothill yellow-legged frog tadpoles from snow-
fed Sierra Nevada populations (North Feather and South Sierra DPSs) 
have higher intrinsic growth rates than tadpoles from rain-fed coastal 
populations (Central Coast and South Coast DPSs), likely due to their 
constraint to a shorter rearing season in the Sierra Nevada (Catenazzi 
and Kupferberg 2017, pp. 1255, 1260-1261).
    As described in the SSA report (Service 2023, pp. 20-23), two 
rangewide assessments of foothill yellow-legged frog genomic datasets 
revealed that this taxon is extremely differentiated following 
biogeographical boundaries (McCartney-Melstad et al. 2018, p. 112; Peek 
2018, p. 76). The clades that are most genetically divergent (i.e., 
South Sierra, Central Coast, and South Coast clades), and thus could 
contribute most to the overall adaptive capacity of this taxon 
(McCartney-Melstad et al. 2018, p. 120; Peek 2018, p. 77), are also the 
clades with the lowest levels of population resiliency. The South 
Sierra and Central Coast clades have substantially reduced resiliency 
and the South Coast clade has extensively reduced resiliency (Service 
2023, pp. 167-170). The reduced resiliency in these clades means that 
the foothill yellow-legged frog is especially vulnerable to loss of 
this genetic diversity. The Central Coast and South Coast clades are 
the most genetically divergent, indicating that a significant amount of 
the taxon's overall genetic diversity would be lost if either clade 
were extirpated. The Central Coast and South Coast clades are also 
ecologically unique because they have lower annual precipitation and 
higher mean annual temperatures than elsewhere in the range of the 
species (PRISM Climate Group 2012, 30-year climate dataset; Service 
2023, pp. 47-51) and the region hosts the highest freshwater endemism 
of anywhere in the species' California range (Howard et al. 2013, p. 
5).
    While the foothill yellow-legged frog clearly has a range of 
genetically divergent populations, it has likely already lost diversity 
due to large extirpations in the southern DPSs. The loss of diversity 
for the four DPSs is at further risk amidst trends toward decreasing 
occupancy and decreasing connectivity (McCartney-Melstad et al. 2018, 
pp. 120-121; Peek 2018, p. 74).
    The trend of decreasing genetic diversity in the foothill yellow-
legged frog may be leading to losses in adaptive capacity (i.e., 
ability to adapt to change). Loss of adaptive capacity lowers a 
species' viability because the decrease in ability to adapt to change 
increases extinction risk in the face of future changes. For foothill 
yellow-legged frog conservation, researchers strongly recommended that 
each of the major genetic groups be managed as independent recovery 
units (McCartney-Melstad et al. 2018, p. 122) and that conservation 
actions should prioritize protecting foothill yellow-legged frogs in 
the Central Coast, South Coast, and South Sierra clades because they 
are simultaneously the most distinct, divergent, and at-risk 
populations (Peek 2018, p. 77).
Redundancy
    Redundancy describes the ability of a species to withstand 
catastrophic events. To assess redundancy for each of the four DPSs, we 
considered the (1) quantity of occupied stream segments (proxy for 
subpopulations) (see table 10 of the SSA report (Service 2023, p. 
130)), (2) spatial distribution of occupied stream segments (see figure 
55 of the SSA report (Service 2023, p. 157)), and (3) population-level 
factors such as connectivity, relative risk of decline, and level of 
threats. These factors were assessed in terms of their potential 
influence on the ability of foothill yellow-legged frog metapopulations 
to survive and recover after a plausible catastrophic event. For 
example, isolation of occupied stream segments or lack of functional 
connectivity in a DPS could prevent recolonization of extirpated areas 
after a massive die-off or temporary habitat destruction.
    The North Feather DPS occupies a relatively small area and several 
streams or occurrences have been extirpated from past impacts (eastern 
portion of range, southwestern area near Lake Oroville, and some 
occurrences in northern Butte County) (CDFW 2020, dataset, entire; 
Service 2023, figure 49, p. 137). The North Feather DPS also has the 
highest average relative risk of population decline with only 16 (15 
percent) of the 109 analyzed stream segments in the low risk category 
and 34 stream segments (31 percent) in the high risk category. Overall 
abundance of foothill yellow-legged frogs for the North Feather DPS is 
largely unknown, but egg mass densities are very low in the two 
regulated stream reaches that have long-term monitoring (Rose et al. 
2020, pp. 63-64, table 1). For example, sections of the Cresta reach of 
the North Feather River that historically had relatively high numbers 
of foothill yellow-legged frog egg masses did not have egg masses or 
were extremely reduced for several years (2006-2017) (CDFW 2019b, p. 
31; Dillingham 2019, p. 7). As a result, redundancy is limited in the 
North Feather DPS. The North Feather DPS is not only the smallest 
clade, but its occupied stream segments are not well-distributed over 
the geographical area (see figure 55 of the SSA report (Service 2023, 
p. 157)). The extant North Feather populations occupy an area small 
enough that a large catastrophic event, such as a high-severity 
wildfire or drought, could

[[Page 59715]]

result in functional extirpation. Furthermore, the North Feather DPS 
has reduced resiliency because of poor occupancy and relatively high 
risk of population decline.
    Redundancy is poor in the South Sierra and Central Coast clades. 
Both the South Sierra and Central Coast clades have substantially 
reduced resiliency because of poor occupancy, poor connectivity, 
relatively high risk of decline, and substantial threats. A single 
catastrophic event would be unlikely to extirpate the entirety of 
either unit, but the patchy distribution of occurrences (see figure 55 
of the SSA report (Service 2023, p. 157)) and limited connectivity 
would make it extremely unlikely that extirpated areas would be 
recolonized naturally.
    Redundancy within the South Coast clade is nearly zero. Not only is 
the resiliency in this clade extensively reduced, but there are only 
two known populations (see section 8.2 of the SSA report (Service 2023, 
pp. 128-145)) in the South Coast clade. These two populations 
(comprised of seven stream segments) are also very close in proximity 
(see figure 55 of the SSA report (Service 2023, p. 157)). These streams 
are located close to one another, but the foothill yellow-legged frog 
populations within them appear to have lost genetic connectivity. 
Although the stream flows are not regulated by dams, the risk of 
population decline continues to be medium or high under current 
conditions due to the combination of threats identified above altering 
habitat and impacting the DPS. Furthermore, the close proximity of the 
stream segments to each other makes the South Coast DPS especially 
vulnerable to extirpation from a single catastrophic event.
Overall Current and Future Condition
    As discussed above, we used the information from the PVA to inform 
both the current condition (Service 2023, chapter 8, pp. 127-172) and 
potential future condition (Service 2023, chapter 9, pp. 173-199) of 
the four DPSs. The PVA assessed how the following measures would change 
from current condition: (1) occupancy and abundance, (2) connectivity, 
(3) modeled risk of population decline, and (4) status of threats under 
each future scenario. Because changes to environmental conditions under 
the future scenarios were reflected by environmental covariates in the 
PVA (see Service 2023, section 9.2 (Scenarios), pp. 176-180, and table 
17), we were able to forecast the magnitudes of changes in resiliency 
by comparing the modeled risk of decline (Rose et al. 2020, entire) 
under current conditions to modeled risk under the three future 
scenarios. The results of the analysis showed that the average risk of 
population decline for each of the four DPSs increased under the three 
future scenarios (Rose et al. 2020, p. 39). Under current conditions 
and all future scenarios, the average relative risk of decline was 
highest in the South Sierra and Central Coast units (Service 2023, 
tables 18 and 19, pp. 184 and 186). Under the lower change scenario, 
decreases in resiliency, compared to current conditions, were small. 
However, decreases in resiliency were more dramatic under the mean and 
higher change scenarios. These declines in resiliency put the four DPSs 
at risk of extirpation or functional extirpation in the future (i.e., 
such extensive reduction in condition that extirpation of the entire 
unit is likely to eventually occur as remnant populations experience 
normal environmental and demographic fluctuations) under the mean and 
higher change scenarios (see table 19 of the SSA report (Service 2023, 
p. 186)). The South Coast DPS is at risk of extirpation under all three 
of the future scenarios due to its low population numbers.

Conservation Efforts and Regulatory Mechanisms

    Several initiatives and conservation efforts are in place and being 
implemented for foothill yellow-legged frog conservation, including 
measures for rearing (headstarting), nonnative species removal, 
development of reintroduction feasibility studies, and habitat 
conservation planning for the species (Service 2023, table 9, pp. 122-
125). The headstarting (hatching eggs and rearing into releasable 
frogs) program has just been started on the North Feather River in a 
portion of the range of the North Feather DPS (GANDA 2018, pp. 1-3, 13, 
table 2; Dillingham 2019, pp. 7-9; Rose et al. 2020, pp. 63-64, 76, 
table 1, figure 4). The Forest Service has noted habitat improvements 
in breeding areas where these in-situ and ex-situ rearing efforts have 
taken place (Dillingham 2019, pp. 7-9). Also benefitting the species 
(through regulatory protection) is the State of California's listing 
under the CESA for each of the four DPSs in 2020 (Commission 2020, p. 
1). Another regulatory benefit that applies to breeding and rearing 
habitat is the 2009 moratorium on suction-dredge mining in California. 
However, benefits to the foothill yellow-legged frog from the 
moratorium have not been studied, and permitting processes are in 
development so that the moratorium may be lifted (State Water Resources 
Control Board 2020, entire).
    The foothill yellow-legged frog is listed as a sensitive species by 
the BLM and the Forest Service under their Sensitive Species Programs 
(BLM 2014a, entire; USFS 2013, entire). These agencies define sensitive 
or at-risk species as those species that require special management 
consideration to promote their conservation and reduce the likelihood 
and need for future listing under the Act. Any actions conducted by 
these agencies would take into consideration impacts to sensitive 
species and, if possible, implement best management practices to limit 
impacts to the species or its habitat.
    As discussed above, FERC issues licenses for the operation of non-
Federal hydropower projects. Within the range of the foothill yellow-
legged frog, numerous hydropower projects require FERC licensing to 
operate. Part of the licensing process includes consideration of 
recommendations for the protection of fish and wildlife. Some FERC 
license requirements have included measures to help protect and 
conserve foothill yellow-legged frogs, such as collection of data, 
implementation of modified flow regimes to mimic more natural 
conditions, and other standard best management practices.
    Two joint Federal and State habitat conservation plans (HCPs) and 
California State natural community conservation plans (NCCPs) (Santa 
Clara Valley HCP/NCCP and East Contra Costa HCP/NCCP) have been 
approved and implemented for the foothill yellow-legged frog as a 
covered species and assist in local population and habitat conservation 
and restoration (Jones & Stokes 2006, entire; ICF International 2012, 
entire). Both HCP/NCCPs are in the northern portion of the Central 
Coast DPS's range.
    Due to the limited nature of existing conservation efforts and no 
rangewide planning or coordination, the current conservation efforts 
are localized. In addition, several ongoing efforts are preliminary 
steps to on-the-ground conservation (e.g., feasibility research) and 
other efforts have not had enough time to verify long-term success 
(e.g., population headstarting) or determine if and how the condition 
of a foothill yellow-legged frog population may have improved (e.g., 
bullfrog removal) (Service 2023, section 7.15, pp. 121-126). Therefore, 
large-scale conservation efforts currently being implemented are not 
known to be ameliorating any of the threats described above for the 
four DPSs but may reduce some effects at the individual or smaller 
localized population levels.

[[Page 59716]]

Determination of Status for the Foothill Yellow-Legged Frog

    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 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.
    In determining potential future threats facing the North Feather, 
South Sierra, Central Coast, and South Coast DPSs, we evaluated various 
future conditions based on projections of changes in threats. Our 
timeframe for review looked out approximately 40 years based on the 
effects of climate change and information developed for the PVA. This 
was our timeframe for our threats analysis of future conditions for the 
four DPSs to determine if they were likely to become endangered within 
the foreseeable future (i.e., if they meet the Act's definition of 
``threatened species'') throughout their ranges.

Status of the South Sierra DPS and the South Coast DPS of the Foothill 
Yellow-Legged Frog Throughout All of Their Ranges

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the South Sierra and South Coast DPSs of the foothill yellow-legged 
frog and their habitats. Below, we summarize our assessment of status 
of the South Sierra DPS and South Coast DPS under the Act.
South Sierra DPS
    Threats are numerous and severe for the South Sierra DPS and 
include altered hydrology (Factor A), agriculture (including airborne 
pesticide drift) (Factor A), illegal cannabis cultivation (Factor A), 
predation by nonnative species (Factor C), disease and parasites 
(Factor C), mining (Factor A), urbanization (including development and 
roads) (Factor A), recreation (Factor E), severe wildfire (Factor A), 
drought (Factor E), extreme flooding (Factor E), and the effects of 
climate change (e.g., increased temperatures, variability in 
precipitation events, increased drought frequency) (Factor E). Existing 
regulatory mechanisms are not sufficient to ameliorate the identified 
threats (Factor D). After evaluating threats to the DPS and assessing 
the cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we conclude that under current conditions, resiliency, 
redundancy, and representation are substantially reduced due to 
existing range contractions and the DPS's extensive extirpations and 
patchy distribution within and between stream segments. Both structural 
and functional connectivity are also poor in the South Sierra DPS. 
Populations within the DPS are relatively small and isolated, and are 
impacted by numerous threats that are of such great extent and 
magnitude that they are making the South Sierra DPS more susceptible to 
loss from stochastic or catastrophic events. The South Sierra DPS also 
has a high average risk of decline with no stream segments in lower 
risk categories under current conditions. As a result, we find that the 
magnitude and imminence of threats facing the South Sierra DPS of the 
foothill yellow-legged frog place the DPS in danger of extinction now, 
and therefore a threatened status is not appropriate. Thus, after 
assessing the best scientific and commercial information available, we 
determine that the South Sierra DPS of the foothill yellow-legged frog 
is in danger of extinction throughout all of its range.
South Coast DPS
    There are numerous, severe threats to the South Coast DPS of the 
foothill yellow-legged frog, including altered hydrology (Factor A), 
drought (Factor E), nonnative species (Factor C), disease and parasites 
(Factor C), urbanization (including development and roads (Factor A) 
and recreation (Factor E)), illegal cannabis cultivation (Factor A), 
extreme floods (Factor E), severe wildfire (Factor A), the effects of 
climate change (e.g., increased temperatures, precipitation 
variability, and increased drought frequency and duration) (Factor E). 
Existing regulatory mechanisms are not sufficient to ameliorate the 
identified threats (Factor D). After evaluating threats to the DPS and 
assessing the cumulative effect of the threats under the Act's section 
4(a)(1) factors, we conclude that under current conditions, resiliency, 
redundancy, and representation are poor for the South Coast DPS. 
Foothill yellow-legged frogs are mostly extirpated in this DPS and 
currently occur only in two streams. These streams are located close to 
one another, but the foothill yellow-legged frog populations within 
them appear to have lost genetic connectivity. Although the stream 
flows are not regulated by dams, the risk of population decline 
continues to be medium or high under current conditions due to the 
combination of threats identified above altering habitat and impacting 
the DPS. Furthermore, the close proximity of the stream segments to 
each other makes the South Coast DPS especially vulnerable to 
extirpation from a single catastrophic event. The area associated with 
the South Coast DPS is subject to reduced precipitation and drying, 
which (1) shortens the hydroperiod and negatively affects habitat 
elements that are hydrology-dependent; (2) limits recruitment, 
survival, and connectivity; and (3) exacerbates the effects of other 
threats, such as predation and wildfire. In addition, the current 
occupancy within the DPS is extremely low and the threats acting on the 
DPS are of such extent and magnitude to result in significant declines. 
As a result, we find that the magnitude and imminence of threats facing 
the South Coast DPS of the foothill yellow-legged frog place the DPS in 
danger of extinction now, and therefore a threatened status is not 
appropriate. Thus, after assessing the best scientific and commercial 
information available, we determine that currently the South Coast DPS 
of the foothill yellow-legged frog is in danger of extinction 
throughout all of its range.

Status of the South Sierra DPS and South Coast DPS Throughout a 
Significant Portion of Their Ranges

    Under the Act and our implementing regulations, a species or DPS 
may warrant listing if it is in danger of extinction or likely to 
become so in the foreseeable future throughout all or a significant 
portion of its range. We have determined that the South Sierra DPS and 
the South Coast DPS of the foothill yellow-legged frog are in danger of 
extinction throughout all of their ranges, and accordingly we did not 
undertake an analysis of any significant portion of the range for these 
two DPSs. Because both DPSs warrant listing as endangered throughout 
all of their ranges, our determination does not conflict with the 
decision in Center for Biological Diversity v. Everson, 435 F. Supp. 3d 
69 (D.D.C. 2020) (Everson), which vacated the provision of the Final 
Policy on

[[Page 59717]]

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) 
providing that if the Services determine that a species is threatened 
throughout all of its range, the Services will not analyze whether the 
species is endangered in a significant portion of its range.

Determination of Status for the South Sierra DPS and South Coast DPS

    Our review of the best available scientific and commercial 
information indicates that the South Sierra DPS and the South Coast DPS 
meet the Act's definition of endangered species. Therefore, we are 
listing the South Sierra DPS and the South Coast DPS of the foothill 
yellow-legged frog as endangered species in accordance with sections 
3(6) and 4(a)(1) of the Act.

Status of the North Feather DPS and Central Coast DPS of the Foothill 
Yellow-Legged Frog Throughout All of Their Ranges

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the North Feather and Central Coast DPSs of the foothill yellow-
legged frog and their habitats. Below, we summarize our assessment of 
status of the North Feather DPS and Central Coast DPS under the Act.
North Feather DPS
    Numerous threats are currently acting on the North Feather DPS. The 
North Feather DPS is within the most hydrologically altered part of the 
foothill yellow-legged frog's range (Factor A) and potentially is among 
the most impacted by the latent effects from historical mining (Hayes 
et al. 2016, pp. 53-54) (Factor A). Other threats to the DPS include 
nonnative species (bullfrogs and crayfish) (Factor C), impacts to 
habitat (agriculture, urbanization, severe wildfire) (Factor A), 
recreation (Factor E), the effects of climate change (Factor E). 
Existing regulatory mechanisms are not sufficient to ameliorate the 
identified threats (Factor D). After evaluating threats to the DPS and 
assessing the cumulative effect of the threats under the Act's section 
4(a)(1) factors, we conclude that under current conditions, resiliency, 
redundancy, and representation for the North Feather DPS are reduced.
    The North Feather DPS occupies a relatively small area and several 
streams or occurrences have been extirpated from past impacts (eastern 
portion of range, southwestern area near Lake Oroville, and some 
occurrences in northern Butte County) (CDFW 2020, dataset, entire; 
Service 2023, figure 49, p. 137). The North Feather DPS also has the 
highest average relative risk of population decline with only 16 (15 
percent) of the 109 analyzed stream segments in the low risk category 
and 34 stream segments (31 percent) in the high risk category. Overall 
abundance of foothill yellow-legged frogs for the North Feather DPS is 
largely unknown, but egg mass densities are very low in the two 
regulated stream reaches that have long-term monitoring (Rose et al. 
2020, pp. 63-64, table 1). For example, sections of the Cresta reach of 
the North Feather River that historically had relatively high numbers 
of foothill yellow-legged frog egg masses did not have egg masses or 
were extremely reduced for several years (2006-2017) (CDFW 2019b, p. 
31; Dillingham 2019, p. 7).
    Under current conditions, resiliency in the North Feather DPS has 
been reduced based on recent occupancy information, largely because of 
the DPS's occupation of a small geographic area, range contraction, the 
relatively high risk of the DPS's decline, and the area's high degree 
of hydrological alteration. However, the North Feather DPS still 
currently contains a relatively high proportion of occurrence records 
with 42 percent of all known occurrences being from the 2010-2020 
timeframe (Service 2023, table 10, figure 49, pp. 130, 137). In 
addition, conservation measures to improve flow regimes to more natural 
conditions and rearing efforts to augment foothill yellow-legged frog 
populations have reduced some current impacts and improved occupancy in 
some areas and as a result have assisted in improving the DPS's current 
condition in these areas. As a result, we consider the current 
occupancy for the North Feather DPS to be stable, based on a majority 
of records being within the 2000-2020 timeframe, but recognize 
population monitoring indicates that the DPS has low abundance and 
limited distribution. Current redundancy is limited in the North 
Feather DPS. The North Feather DPS not only occupies the smallest area, 
but its occupied stream segments are not well-distributed over the 
geographical area it occupies. Current representation of the DPS is 
most likely reduced due to past loss of populations.
    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the section 4(a)(1) factors, we 
have determined that, even with the current condition of the DPS being 
reduced, the population and habitat factors used to determine the 
resiliency, representation, and redundancy for the DPS have not been 
reduced to such a degree to consider the North Feather DPS currently in 
danger of extinction throughout its range.
    However, threat conditions in the future are likely to 
substantially impact populations of the North Feather DPS. Because of 
the current cold stream temperatures, future climatic conditions that 
may increase stream temperatures may potentially benefit many of the 
North Feather DPS populations; however, the negative effects of 
increases in streamflow variability due to climate change (i.e., 
drought/flood events, snow/rain events) and residual environmental 
stochasticity likely outweigh the benefit of any warmer stream 
temperatures. Increased water demand and anticipated additional 
regulation to an already highly regulated hydrologic condition of the 
DPS's habitat will further limit the DPS's capability to maintain 
adequate population sizes to support the DPS's metapopulation 
structure. Nonnative species (bullfrogs and crayfish) will continue to 
impact the DPS, and their impacts may increase as temperatures warm, 
allowing for spread of warm water species such as bullfrogs and 
smallmouth bass. Trends indicate that the amount of area severely 
burned annually by wildfires has been growing sharply in the range of 
the North Feather DPS (Service 2023, figures 38 and 39, pp. 109-110), 
and negative consequences from wildfire-related sedimentation to 
foothill yellow-legged frog reproduction have been documented in this 
DPS (Service 2023, pp. 103-113). The populations of the North Feather 
DPS occupy an area small enough that a large catastrophic event, such 
as a severe wildfire or prolonged drought, could result in a severe 
reduction in population size and extent for the DPS. In the SSA report 
we identified three future scenarios to assist in evaluating the future 
resiliency of the DPSs. These included a lower change scenario, a 
higher change scenario, and a mean change scenario. All three of these 
scenarios took into account each DPSs current resiliency and provided 
information on any changes from the DPSs current resiliency. For the 
North Feather DPS, the DPS's current resiliency is considered reduced. 
Under the lower change scenario the DPS is continued to have reduced 
resiliency, under the mean change scenario the DPS is expected to have 
a markedly reduced resiliency and be at risk of functional extirpation, 
and under the higher change scenario the DPS is

[[Page 59718]]

expected to have a greatly reduced resiliency and be at risk of 
functional extirpation or be extirpated. Based on this information, we 
have determined that the future resiliency for the North Feather DPS 
will be markedly reduced as a result of the increases in threats and 
increases in the synergistic effects of threat interactions on the DPS, 
as well as the DPS's response to the threats as identified above. Thus, 
the projected increases in average relative risk of decline under 
future conditions under the mean change scenario are likely to decrease 
occupancy, abundance, and connectivity, with resiliency being markedly 
reduced from the DPS's current condition within 40 years.
    As a result of the DPS having a large percentage (70 percent) of 
stream segments occupied (since 2000) with a large proportion of those 
segments (42 percent) being occupied since 2010, and implementation of 
conservation measures to reduce the effects of altered stream hydrology 
and provide for an increase in populations, we have determined that the 
current condition of the DPS, although reduced, still exhibits 
sufficient resiliency, redundancy, and representation and provide for, 
at a minimum, areas of favorable conditions that allow the North 
Feather DPS to currently sustain its existing populations. However, 
future impacts from the threats facing the DPS are likely to cause 
declines in the DPS's population size and distribution. Thus, after 
assessing the best available information, we conclude that the North 
Feather DPS of the foothill yellow-legged frog 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.
Central Coast DPS
    Numerous threats are currently acting on the Central Coast DPS, 
including altered hydrology (Factor A), disease (Factor C), drought 
(Factor A), nonnative bullfrogs (Factor C), impacts to habitat 
(urbanization (including development and roads), agriculture, trespass 
cannabis cultivation, extreme floods, and wildfire) (Factor A), 
recreation (Factor E), the effects of climate change (Factor E). 
Existing regulatory mechanisms are not sufficient to ameliorate the 
identified threats (Factor D). Human land use and population (urban 
development) in the northern portions of the DPS's range are high, and 
the proportion of forest and shrub cover across the DPS's range is low, 
with large areas being made up of lower elevation open oak woodlands or 
foothill grassland habitats. Seasonal precipitation within the range of 
the Central Coast DPS is extremely variable year-to-year, making stream 
habitat for the Central Coast DPS subject to drying. This, in turn, 
shortens the breeding season; negatively affects habitat elements that 
are hydrology-dependent; limits recruitment, survival, and 
connectivity; and exacerbates the effects of other threats (e.g., 
wildfire, drought, nonnative predators, disease, and the effects of 
climate change). However, this variability has also resulted in the 
Central Coast area of California (including the area occupied by the 
Central Coast DPS) containing a high number of freshwater species that 
have evolved adaptations to their environment (Howard et al. 2013, p. 
5). Below, we summarize the resiliency, redundancy, and representation 
of the Central Coast DPS.
    The Central Coast DPS has undergone historical range contraction in 
portions of its northern (Contra Costa, Alameda, San Mateo, and 
northern Santa Cruz Counties) and central (southern Santa Clara and 
northern San Benito Counties) regions. Currently, two clusters of 
stream segments have had recent (2000-2020) detections of the species, 
one cluster in the southern part and one cluster in the northern part 
of the DPS's range (Service 2023, figure 52, p. 143). Population size 
and abundance for the Central Coast DPS have been historically and 
continue to be small, with those populations in unregulated streams 
being larger and more productive (Service 2023, pp. 142-143). The 
southern cluster appears to have functional connectivity and therefore 
have the ability to share genetic material between populations 
(McCartney-Melstad et al. 2018, p. 117, figure 3 (2C)), which assists 
in maintaining the cluster's metapopulation integrity. The southern 
cluster also has fewer human-caused threats (e.g., urbanization, 
recreation) due to its distance away from highly human-populated areas 
and its location on public lands (BLM's Clear Creek Management Area 
(CCMA)). Populations within the CCMA in San Benito and Fresno Counties 
are being monitored and managed by BLM, and currently appear to be 
self-sustaining (BLM 2014b, pp. 4-77, 99-100). The northern cluster is 
proximate to highly urbanized areas of the south San Francisco Bay area 
and San Jose, California. The northern cluster exhibits some genetic 
differentiation among subpopulations, indicating that the DPS has a 
lack of functional connectivity (McCartney-Melstad et al. 2018, p. 117, 
figure 3 (4B)). However, two HCP/NCCPs (East Contra Costa and Santa 
Clara Valley) (Jones & Stokes 2006, entire; ICF International 2012, 
entire) that identify the foothill yellow-legged frog as a covered 
species have been approved and implemented. These plans assist in 
ameliorating the current threats acting on the northern populations of 
the Central Coast DPS and help conserve the DPS and its habitat within 
their jurisdictional boundaries.
    Current resiliency of the Central Coast DPS is substantially 
reduced due to past impacts limiting connectivity between populations 
and existing populations having smaller population abundance and 
breeding (Rose et al. 2020, p. 63, table 1). The average risk of 
population decline for the Central Coast DPS is considered high and 
numerous threats (altered hydrology, drought, nonnative species, 
disease, and urbanization) are currently acting on the DPS. The current 
overall redundancy for the Central Coast DPS is considered adequate to 
guard against catastrophic events. This is because the Central Coast 
DPS has numerous occupied stream segments that are spatially 
distributed across the DPS's range, and those stream segments exhibit 
variable environmental conditions providing for, at a minimum, refugia 
for the population. As a result of this distribution, the likelihood 
that a single catastrophic event would impact a significant proportion 
of the Central Coast DPS's populations to the point of extirpation or 
functional extirpation is extremely small. Current representation for 
the Central Coast DPS is considered sufficient to maintain its adaptive 
capacity. The Central Coast DPS has evolved in an area with high 
climatic variability and is most likely adapted to environmental 
changes. The Central Coast DPS is also one of the most genetically 
divergent for the foothill yellow-legged frog, indicating that the DPS 
still contains a significant amount of the taxon's overall genetic 
diversity.
    In the future, the average risk of decline for the existing 
populations is expected to increase by 14 percent and the number of 
populations at high risk of decline are expected to increase by 69 
percent, under the mean change scenario. The lower change scenario 
identified resiliency as slightly reduced from the DPSs current reduced 
resiliency and the high change scenario identified the resiliency for 
the DPS to be greatly reduced with a risk of functional extirpation or 
extirpation due to its reduced ability to withstand stochastic events. 
These changes are a result of increases in threats such as climate-
induced demand for surface waters that is projected to increase by 5 to 
20 percent (from 1900-1970 levels)

[[Page 59719]]

by mid-century (2050) (Averyt et al. 2013, p. 7, figure 7). Future 
increases in severe wildfires are expected. Despite wildfire trends in 
the Central Coast DPS being stable between 1950 and 2018 (Service 2023, 
figure 38, p. 109), recent events such as the fires in 2020 in the San 
Mateo-Santa Cruz Unit (CZU) (35,009 hectares (ha) (86,509 acres (ac)) 
(Santa Cruz and San Mateo Counties) and Santa Clara Unit (SCU) (160,508 
ha (396,624 ac)) (Santa Clara, Alameda, and Stanislaus Counties) 
Lightning Complex are examples of expected increasing trends in 
wildfire activity in the future (CALFIRE 2021, entire). Under the lower 
change scenario, the Central Coast DPS's resiliency would be slightly 
reduced. Under the mean change scenario, resiliency would be markedly 
reduced from current condition due to reductions in population numbers 
and distribution (reduction in redundancy). This reduction in 
resiliency under the mean change scenario would put the Central Coast 
DPS at risk of functional extirpation or extirpation within 40 years.
    After evaluating threats to the Central Coast DPS and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we find that the Central Coast DPS of the foothill yellow-
legged frog currently sustains numerous populations and contains 
habitat distributed throughout the DPS's range (redundancy). These 
widely distributed populations provide for the genetic and ecological 
representation for the DPS across its range. Therefore, the current 
resiliency, redundancy, and representation are sufficient to prevent 
the current threats acting on the Central Coast DPS from causing it to 
be in danger of extinction currently. Thus, the Central Coast DPS of 
the foothill yellow-legged frog is not currently in danger of 
extinction throughout its range, and, therefore, the Central Coast DPS 
does not meet the Act's definition of an endangered species. However, 
based on our projections of future occupancy, modeled risk of decline 
assessments from the PVA, and the existing and increased threats in the 
future on the DPS from increasing water demand, increases in wildfire 
frequency and intensity due to climate change conditions will further 
impact abundance and connectivity of populations and cause the DPS's 
habitat to become increasingly less able to support foothill yellow-
legged frog populations into the future. Thus, after assessing the best 
information available, we conclude that the Central Coast DPS of the 
foothill yellow-legged frog is likely to become in danger of extinction 
within the foreseeable future throughout all of its range.

Status of the North Feather DPS and Central Coast DPS of the Foothill 
Yellow-Legged Frog Throughout a Significant Portion of Their Ranges

    Under the Act and our implementing regulations, a species or DPS 
may warrant listing if it is in danger of extinction or likely to 
become so in the foreseeable future throughout all or a significant 
portion of its range. 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'' 
(herein after ``Final Policy''; 79 FR 37578, July 1, 2014) that 
provided if the Services determine that a species or DPS is threatened 
throughout all of its range, the Services will not analyze whether the 
species or DPS is endangered in a significant portion of its range.
    Therefore, we proceed to evaluating whether the North Feather DPS 
or Central Coast DPS is endangered in a significant portion of its 
range--that is, whether there is any portion of either DPS's 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 either 
DPS's range.
    Following the court's holding in Everson, we now consider whether 
there are any significant portions of either of the two DPSs' ranges 
where either DPS is in danger of extinction now (i.e., endangered). In 
undertaking this analysis for the North Feather DPS and Central Coast 
DPS, we choose to address the status question first--we consider 
information pertaining to the geographic distribution of both the 
species and the threats that the two DPSs face to identify any portions 
of either DPS's range where either is endangered. Below we provide our 
significant portion of the range analysis for the North Feather DPS and 
Central Coast DPS.

North Feather DPS

    We evaluated the range of the North Feather DPS to determine if the 
DPS is in danger of extinction now in any portion of its range. The 
range of a species can theoretically be divided into portions in an 
infinite number of ways. We focused our analysis on portions of the 
species' range that may meet the definition of an endangered species. 
For the North Feather DPS, due to its relatively small distribution, we 
considered whether the threats or their effects on the species are 
greater in any biologically meaningful portion of the species' range 
than in other portions such that the species is in danger of extinction 
now in that portion.
    For the North Feather DPS, we examined the following major threats: 
altered stream hydrology or other habitat impacts, nonnative species, 
severe wildfire, recreation, and the effects of climate change, 
including cumulative effects.
    The current resiliency of the North Feather DPS is considered 
reduced when compared to conditions prior to the year 2000, with 
approximately 70 percent of locations being occupied over the 2000-2020 
timeframe. However, the DPS still has a relatively high proportion of 
presumed occupied and well distributed stream segments relative to the 
number of potential stream segments. Most of the recent records of the 
DPS are distributed within two major stream segments and their 
tributaries within the DPS's range. The major driving threats 
identified above are currently acting uniformly within these stream 
segments and tributaries. The implementation of conservation efforts 
such as reintroductions and stream flow management on regulated streams 
have assisted in maintaining and reducing the current threats for the 
DPS. The major driving threats associated with severe wildfire, altered 
hydrology, and the effects of climate change are all expected to 
increase in the future but we expect the DPS to have sufficient 
resiliency, redundancy, and representation to maintain populations in 
the wild as based on occupancy over the last 20 years. The current 
threat conditions and impacts from those threats on the North Feather 
DPS across its range are relatively uniform as based on the modeling 
efforts used to determine the species current conditions (Service 2023, 
table 19, p. 186). This information regarding the DPS's current 
condition, risk of decline, and uniformity and timing of threats all 
confirm our determination that the DPS currently meets the definition 
of threatened and that there are no portions of its range where the DPS 
is currently endangered.
    We found no biologically meaningful portion of the North Feather 
DPS's range where threats are impacting individuals

[[Page 59720]]

differently from how they are affecting the DPS elsewhere in its range, 
or where the biological condition of the DPS differs from its condition 
elsewhere in its 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 North Feather 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.

Central Coast DPS

    We evaluated the range of the Central Coast DPS to determine if the 
DPS is in danger of extinction now in any portion of its range. The 
range of a species or DPS can theoretically be divided into portions in 
an infinite number of ways. We focused our analysis on portions of the 
DPS's range that may meet the definition of an endangered species. For 
the Central Coast DPS, we considered whether the threats or their 
effects on the species are greater in any biologically meaningful 
portion of the species' range than in other portions such that the 
species is in danger of extinction now in that portion.
    The statutory difference between an endangered species and a 
threatened species is the timeframe in which the species or DPS becomes 
in danger of extinction; an endangered species is in danger of 
extinction now while a threatened species is not in danger of 
extinction now but is likely to become so in the foreseeable future. 
Thus, we reviewed the best scientific and commercial data available 
regarding the time horizon for the threats that are driving the Central 
Coast DPS to warrant listing as a threatened species throughout all of 
its range. We then considered whether these threats or their effects 
are occurring (or may imminently occur) in any portion of the species' 
range with sufficient magnitude such that the DPS is in danger of 
extinction now in that portion of its range. We examined the following 
threats: altered hydrology, drought, nonnative bullfrogs, Bd (disease), 
agriculture (especially illegal cannabis cultivation), mining, 
urbanization (including roads and recreation), extreme flood events, 
and the effects of climate change, including cumulative effects. For 
the Central Coast DPS, we have determined that urbanization and 
associated human impacts (roads and recreation) most likely have 
disproportional impacts in certain areas in the northern portion of the 
DPS's range.
    In the northern portion of the Central Coast DPS's range at lower 
elevation in highly urbanized areas (such as San Francisco and East 
Bay), impacts from threats associated with development and human land 
use are particularly high (Service 2023, figure 55, p. 157). This 
corresponds to an observed pattern of historical decline of the Central 
Coast DPS's occupancy in this northern portion of its range where few 
recent (i.e., 2000-2020) records exist directly south or directly east 
of the San Francisco Bay (Service 2023, figure 52, p. 143). According 
to the PVA, the stream segments in this northern portion were also 
identified as having the highest risks of decline when compared to 
stream segments in other parts of the Central Coast DPS's range 
(Service 2023, figure 55, p. 157). This pattern of elevated risk 
suggests that extirpations of the foothill yellow-legged frog in the 
northern portion of the Central Coast DPS's range are more likely to 
occur. However, within this northern portion currently the Central 
Coast DPS is still well distributed with approximately 50 percent of 
records since between 2000 and 2020 being confirmed over the 2010-2020 
timeframe. In addition, foothill yellow-legged frog populations within 
this northern portion are located in streams and watersheds outside the 
lower elevation areas and are not currently subject to widespread or 
significant threats from urban development. In addition, current 
conservation efforts in the northern portion associated with the East 
Contra Costa HCP and the Santa Clara Valley HCP are currently being 
implemented to protect and conserve foothill yellow-legged frogs and 
their habitat and we expect that these efforts will reduce the level of 
threats and provide benefits to the DPS's habitat in this northern 
portion.
    Although within the northern portion of the Central Coast DPS's 
range, some threats to the DPS are impacting individuals differently 
from how they are affecting the species elsewhere in its range, the 
best scientific and commercial data available do not indicate that the 
threats, or the DPS's responses to the threats, are such that the 
Central Coast DPS is in danger of extinction now in the northern 
portion of its range. Therefore, we determine, that the species is 
likely to become in danger of extinction within the foreseeable future 
throughout all of its range.
    Therefore, no portions of the North Feather DPS or Central Coast 
DPS ranges provides a basis for determining that either DPS is in 
danger of extinction in a significant portion of its respective range, 
and we determine that the DPSs are likely to become in danger of 
extinction within the foreseeable future throughout all of their 
ranges. 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 for the North Feather DPS and Central Coast DPS 
of the Foothill Yellow-Legged Frog

    Our review of the best scientific and commercial information 
available indicates that the North Feather DPS and Central Coast DPS of 
the foothill yellow-legged frog are likely to become endangered species 
within the foreseeable future throughout their ranges and thus meet the 
Act's definition of threatened species. Therefore, we are listing the 
North Feather DPS and Central Coast DPS of the foothill yellow-legged 
frog as threatened species in accordance with sections 3(20) and 
4(a)(1) of the Act.

Available Conservation Measures

    Conservation measures provided to species or DPSs 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-

[[Page 59721]]

sustaining, and functioning components of their ecosystems.
    Recovery planning consists of preparing draft and final recovery 
plans, beginning with the development of a recovery outline and making 
it available to the public within 30 days of a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions and describes the process to be used to 
develop a recovery plan. Revisions of the plan may be done to address 
continuing or new threats to the species, as new substantive 
information becomes available. The recovery plan also 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 a framework 
for agencies to coordinate their recovery efforts and provide estimates 
of the cost of implementing recovery tasks. Recovery teams (composed of 
species experts, Federal and State agencies, nongovernmental 
organizations, and stakeholders) are often established to develop 
recovery plans. When completed, the recovery outline, draft recovery 
plan, and the final recovery plan will be available on our website 
(https://www.fws.gov/program/endangered-species), or from our 
Sacramento Fish and Wildlife Office (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 species 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 State of California will be 
eligible for Federal funds to implement management actions that promote 
the protection or recovery of the DPSs. 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 foothill yellow-legged frog. Additionally, we 
invite you to submit any new information on this species whenever it 
becomes available and any information you may have for recovery 
planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their 
actions with respect to any species that is proposed or listed as an 
endangered or threatened species and with respect to its critical 
habitat, if any is designated. Regulations implementing this 
interagency cooperation provision of the Act are codified at 50 CFR 
part 402. Section 7(a)(2) of the Act requires Federal agencies to 
ensure that activities they authorize, fund, or carry out are not 
likely to jeopardize the continued existence of any endangered or 
threatened species or destroy or adversely modify its critical habitat. 
If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with the Service.
    Examples of Federal agency actions within the species' habitat 
within the DPSs that may require conference or consultation or both, as 
described in the preceding paragraph, include, but are not limited to, 
management and any other landscape-altering activities on Federal lands 
administered by the U.S. Fish and Wildlife Service, Forest Service, 
BLM, and National Park Service; issuance of section 404 Clean Water Act 
(33 U.S.C. 1251 et seq.) permits by the U.S. Army Corps of Engineers; 
construction and maintenance of roads, bridges, or highways by the 
Federal Highway Administration; water management and conveyance 
activities by the Bureau of Reclamation; and licensing for hydropower 
and safety of dams by the FERC.

South Sierra DPS and South Coast DPS--Endangered Status

    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to endangered wildlife. 
The prohibitions of section 9(a)(1) of the Act, codified at 50 CFR 
17.21, make it illegal for any person subject to the jurisdiction of 
the United States to take (which includes harass, harm, pursue, hunt, 
shoot, wound, kill, trap, capture, or collect; or to attempt any of 
these) endangered wildlife within the United States or on the high 
seas. In addition, it is unlawful to import; export; deliver, receive, 
carry, transport, or ship in interstate or foreign commerce in the 
course of commercial activity; or sell or offer for sale in interstate 
or foreign commerce any species listed as an endangered species. It is 
also illegal to possess, sell, deliver, carry, transport, or ship any 
such wildlife that has been taken illegally. Certain exceptions apply 
to employees of the Service, the National Marine Fisheries Service, 
other Federal land management agencies, and State conservation 
agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations 
governing permits are codified at 50 CFR 17.22. With regard to 
endangered wildlife, a permit may be issued for the following purposes: 
For scientific purposes, to enhance the propagation or survival of the 
species, and for incidental take in connection with otherwise lawful 
activities. The statute also contains certain exemptions from the 
prohibitions, which are found in sections 9 and 10 of the Act.
    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify to the maximum extent practicable at 
the time a species is listed, those activities that would or would not 
constitute a violation of section 9 of the Act. The intent of this 
policy is to increase public awareness of the effect of a final listing 
on proposed and ongoing activities within the range of the listed 
species.
    Because activities being implemented in the range of the species 
are variable and have variable impacts depending on the nature of the 
project, we are unable at this time to identify any specific activities 
within the range of the species that would not constitute a violation 
of section 9, as effects of any actions on the species are fact-pattern 
specific. However, actions whose effects do not extend into foothill 
yellow-legged frog habitat are unlikely to result in section 9 
violations.
    Based on the best available information, the following activities 
that the Service believes could potentially harm the foothill yellow-
legged frog and result in ``take'' and, therefore, may result in a 
violation of section 9 of the Act if they are not authorized in 
accordance with applicable law include, but are not limited to:
    (1) Unauthorized handling or collecting of the species;
    (2) Destruction/alteration of the species' habitat by discharge of 
fill material, draining, ditching, tiling, pond construction, stream 
channelization or

[[Page 59722]]

diversion, or diversion or alteration of surface or ground water flow;
    (3) Inappropriate livestock grazing that results in direct or 
indirect destruction of riparian habitat;
    (4) Pesticide applications in violation of label restrictions;
    (5) Introduction of nonnative species that compete with or prey 
upon foothill yellow-legged frogs, such as the introduction of 
nonnative bullfrogs or nonnative fish; and
    (6) Modification of the channel or water flow of any stream or 
removal or destruction of vegetation or stream substrate in any body of 
water in which the foothill yellow-legged frog is known to occur.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Sacramento 
Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

North Feather DPS and Central Coast DPS--Threatened Status

    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify to the maximum extent practicable at 
the time a species is listed, those activities that would or would not 
constitute a violation of section 9 of the Act. The intent of this 
policy is to increase public awareness of the effect of a final listing 
on proposed and ongoing activities within the range of the listed 
species. The discussion below regarding protective regulations under 
section 4(d) of the Act for the North Feather DPS and Central Coast 
DPS, which we are listing as threatened in this rule, complies with our 
policy.

II. Final Rules Issued Under Section 4(d) of the Act for the North 
Feather DPS and the Central Coast DPS of the Foothill Yellow-Legged 
Frog

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. The U.S. Supreme Court has noted that statutory 
language like ``necessary and advisable'' demonstrates a large degree 
of deference to the agency (see Webster v. Doe, 486 U.S. 592 (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 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 the prohibitions under section 9 for any particular threatened 
species or DPS.
    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 rules 
developed under section 4(d) as a valid exercise of agency authority 
where they prohibit take of threatened wildlife or include a limited 
taking prohibition (see Alsea Valley Alliance v. Lautenbacher, 2007 
U.S. Dist. Lexis 60203 (D. Or. 2007); Washington Environmental Council 
v. National Marine Fisheries Service, 2002 U.S. Dist. Lexis 5432 (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 of 
the Act, ``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 [she] 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).
    Exercising this authority under section 4(d), we have developed 
rules that are designed to address the conservation needs of the North 
Feather DPS and Central Coast DPS of the foothill yellow-legged frog. 
Although the statute does not require us to make a ``necessary and 
advisable'' finding with respect to the adoption of specific 
prohibitions under section 9, we find that these rules 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 
North Feather DPS and Central Coast DPS of the foothill yellow-legged 
frog. As discussed above under Summary of Biological Status and 
Threats, we have concluded that the North Feather DPS and Central Coast 
DPS of the foothill yellow-legged frog are likely to become in danger 
of extinction within the foreseeable future throughout their respective 
ranges primarily due to threats associated with altered stream 
hydrology, nonnative species, impacts to habitat (agriculture, mining, 
urbanization, roads, recreation), disease, drought, extreme floods, 
high-severity wildfire, and the exacerbation of threats from the 
effects of climate change. The provisions of these 4(d) rules will 
promote conservation of the North Feather DPS and Central Coast DPS of 
the foothill yellow-legged frog by encouraging management of each of 
the DPS's stream habitat and landscape in ways that meet both resource 
management considerations and the conservation needs of the DPSs. The 
provisions of these rules are one of many tools that we will use to 
promote the conservation of the North Feather DPS and Central Coast DPS 
of the foothill yellow-legged frog. For these reasons, we find the 4(d) 
rules as a whole are necessary and advisable to provide for the 
conservation of the North Feather and Central Coast DPSs of the 
foothill yellow-legged frog.
    Section 7(a)(2) of the Act requires Federal agencies, including the 
Service, to ensure that any action they fund, authorize, 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.
    If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with the Service. Examples of actions that are subject to 
the section 7 consultation process are 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, a license from the FERC under the Federal Power Act (16 U.S.C. 
791a 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 
the 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.
    This obligation does not change in any way for a threatened species 
with a species-specific 4(d) rule. Actions that result in a 
determination by a Federal

[[Page 59723]]

agency of ``not likely to adversely affect'' continue to require the 
Service's written concurrence and actions that are ``likely to 
adversely affect'' a species require formal consultation and the 
formulation of a biological opinion.

Provisions of the 4(d) Rules for the North Feather DPS and the Central 
Coast DPS of the Foothill Yellow-Legged Frog

    The 4(d) rules will provide for the conservation of the North 
Feather DPS and Central Coast DPS of the foothill yellow-legged frog by 
prohibiting the following activities, except as otherwise authorized or 
permitted: import or export; take; possession and other acts with 
unlawfully taken specimens; delivery, receipt, carriage, 
transportation, or shipment in interstate or foreign commerce in the 
course of commercial activity; or sale or offer for sale in interstate 
or foreign commerce. These prohibitions mirror those prohibitions 
afforded to endangered species under section 9(a)(1) of the Act.
    In addition to the prohibited activities identified above, we also 
provide standard and other exceptions to those prohibitions for certain 
activities as described below.
    We note that the long-term viability of the North Feather DPS and 
Central Coast DPS of the foothill yellow-legged frog, as with many 
wildlife species, is intimately tied to the condition of their habitat. 
As described in our analysis of the species' status, one of the major 
threats to the North Feather DPS and Central Coast DPS of the foothill 
yellow-legged frog's continued viability is habitat loss, degradation, 
and fragmentation resulting from past or current anthropogenic impacts 
or from catastrophic wildfires. The potential for an increase in 
frequency and severity of catastrophic wildfires from the effects of 
climate change subsequently increases the risk to the DPSs posed by 
this threat. An additional threat is the occurrence of nonnative 
species that may predate upon and compete for resources with the 
foothill yellow-legged frog.
    We have determined that actions taken by forest management entities 
in the range of the North Feather DPS and Central Coast DPS of the 
foothill yellow-legged frog for the purpose of reducing the risk or 
severity of catastrophic wildfires and protecting stream habitat, even 
if these actions may result in some short-term or low level of 
localized negative effect to the North Feather DPS and/or Central Coast 
DPS of the foothill yellow-legged frog, will further the goal of 
reducing the likelihood of either DPS becoming endangered, and will 
also likely contribute to their conservation and long-term viability. 
This includes measures to conduct wildfire prevention activities, non-
emergency suppression activities, and other silviculture best 
management practices that are in accordance with an established forest 
or fuels management plan that follow current State of California Forest 
Practice Rules, State fire codes, or local fire codes/ordinances as 
appropriate.
    In addition, habitat restoration efforts that specifically provide 
for the habitat needs of the North Feather DPS and Central Coast DPS of 
the foothill yellow-legged frog and include measures that minimize 
impacts to the species and its habitat are an exception to the 
prohibitions. These efforts must be carried out in accordance with 
finalized conservation plans or strategies specifically identified for 
the foothill yellow-legged frog and include measures that minimize 
impacts to the North Feather and Central Coast DPSs. These activities 
will most likely have some limited short-term impacts but overall will 
provide for conservation of the two DPSs.
    Removal and restoration of trespass cannabis cultivation sites are 
also excepted from prohibitions. These activities will benefit the 
foothill yellow-legged frog, especially in the Central Coast DPS area. 
Trespass cannabis cultivation sites cause several issues for the 
foothill yellow-legged frog, including water diversion, pollution, 
sedimentation, and introduction of pesticides and fertilizers to 
streams occupied by the foothill yellow-legged frog. When these sites 
are found, they often require reclamation (waste cleanup and removal of 
fertilizers, pesticides, and debris) and restoration to precultivation 
conditions. Cleanup of these sites may involve activities that may 
cause localized, short-term disturbance to the North Feather DPS and 
Central Coast DPS of the foothill yellow-legged frog. However, the 
removal of pesticides and other chemicals that can affect the North 
Feather DPS or Central Coast DPS of the foothill yellow-legged frog and 
the surrounding environment is encouraged. Removal and restoration of 
trespass cannabis cultivation sites is expected to have long-term 
benefits for resiliency of the North Feather DPS and Central Coast DPS.
    Nonnative species removal will significantly increase the viability 
of the foothill yellow-legged frog. As discussed above, bullfrogs, 
nonnative fish, and nonnative crayfish contribute to foothill yellow-
legged frog predation and increase competition for resources. Bullfrogs 
also are vectors for disease that affects the foothill yellow-legged 
frog. Actions with the primary or secondary purpose of removing 
nonnative animal species that compete with, predate upon, or degrade 
the habitat of the foothill yellow-legged frog that are conducted in 
unoccupied habitat are provided as an exception to the prohibitions. 
Actions that disturb habitat, involve the use of chemicals, or are 
conducted in occupied stream segments are not included.
    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 
regulations 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 species' remaining populations, slow their 
rate of decline, and decrease synergistic, negative effects from other 
ongoing or future threats.
    We may issue permits to carry out otherwise prohibited activities, 
including those described above, involving threatened wildlife under 
certain circumstances. Regulations governing permits are codified at 50 
CFR 17.32. With regard to threatened wildlife, a permit may be issued 
for the following purposes: For scientific purposes, to enhance 
propagation or survival, for economic hardship, for zoological 
exhibition, for educational purposes, for incidental taking, or for 
special purposes consistent with the purposes of the Act. The statute 
also contains certain exemptions from the prohibitions, which are found 
in sections 9 and 10 of the Act and are included as standard exceptions 
in the 4(d) rule.
    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 the Service in implementing all aspects of the Act. 
In this regard, section 6 of the Act provides that the Service shall 
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 the Service in accordance with section 6(c) 
of the Act, who is designated by his or her

[[Page 59724]]

agency for such purposes, will be able to conduct activities designed 
to conserve the foothill yellow-legged frog, that may result in 
otherwise prohibited take, without additional authorization.
    Nothing in these 4(d) rules 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 foothill yellow-
legged frog. However, interagency cooperation may be further 
streamlined through planned programmatic consultations for the species 
between Federal agencies and the Service, where appropriate.

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 provisions of 
section 4 of this 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
    (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.

Prudency Determination

    Section 4(a)(3) of the Act, as amended, and implementing 
regulations (50 CFR 424.12) require that, to the maximum extent prudent 
and determinable, the Secretary shall designate critical habitat at the 
time the species is determined to be an endangered or threatened 
species. Our regulations (50 CFR 424.12(a)(1)) state that the Secretary 
may, but is not required to, determine that a designation would not be 
prudent in the following circumstances:
    (i) The species is threatened by taking or other human activity and 
identification of critical habitat can be expected to increase the 
degree of such threat to the species;
    (ii) The present or threatened destruction, modification, or 
curtailment of a species' habitat or range is not a threat to the 
species, or threats to the species' habitat stem solely from causes 
that cannot be addressed through management actions resulting from 
consultations under section 7(a)(2) of the Act;
    (iii) Areas within the jurisdiction of the United States provide no 
more than negligible conservation value, if any, for a species 
occurring primarily outside the jurisdiction of the United States;
    (iv) No areas meet the definition of critical habitat; or
    (v) The Secretary otherwise determines that designation of critical 
habitat would not be prudent based on the best scientific data 
available.
    As discussed earlier in this document, we did not identify an 
imminent threat of collection or vandalism identified under Factor B 
for this species, and identification and mapping of critical habitat is 
not expected to initiate any such threat. In our SSA report and this 
final listing determination for the four DPSs of the foothill yellow-
legged frog, we determined that the present or threatened destruction, 
modification, or curtailment of habitat or range (Factor A) is a threat 
to the four DPSs and that the Factor A threats in some way can be 
addressed by the Act's section 7(a)(2) consultation measures. The four 
DPSs occur wholly in the jurisdiction of the United States, and we are 
able to identify areas that meet the definition of critical habitat. 
Therefore, because none of the circumstances enumerated in our 
regulations at 50 CFR 424.12(a)(1) have been met and because the 
Secretary has not identified other circumstances for which this 
designation of critical habitat would be not prudent, we have 
determined that the designation of critical habitat is prudent for the 
four DPSs of the foothill yellow-legged frog.

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.''
    We reviewed the available information pertaining to the biological 
needs of the four DPSs of the foothill yellow-legged frog and habitat 
characteristics where the four DPSs are located. A careful assessment 
of the economic impacts that may occur due to a critical habitat 
designation is still ongoing, and we are in the process of working with 
the State and other partners in acquiring 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 four DPSs of the foothill 
yellow-legged frog is not determinable at this time. 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

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), Executive Order 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. We solicited information from all of 
the Tribes within the entire range of the foothill yellow-legged frog 
to inform the development of the SSA report, and we notified Tribes of 
our proposed and this final listing determination. We also

[[Page 59725]]

provided these Tribes the opportunity to review a draft of the SSA 
report and provide input prior to making our determination on the 
status of the foothill yellow-legged frog, but we did not receive any 
responses. We will continue to coordinate with Tribal entities 
throughout the recovery and critical habitat designation processes for 
the foothill yellow-legged frog.

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 Sacramento Fish and Wildlife Office (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 Field Office staff 
in the Sacramento Fish and Wildlife Office and Ventura Fish and 
Wildlife Office in California.

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. In Sec.  17.11, amend paragraph (h) by adding entries for ``Frog, 
foothill yellow-legged [Central Coast DPS]'', ``Frog, foothill yellow-
legged [North Feather DPS]'', ``Frog, foothill yellow-legged [South 
Coast DPS]'', and ``Frog, foothill yellow-legged [South Sierra DPS]'' 
to the List of Endangered and Threatened Wildlife in alphabetical order 
under AMPHIBIANS to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                           Listing citations and
          Common name              Scientific name       Where listed         Status         applicable rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                   Amphibians
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Frog, foothill yellow-legged     Rana boylii........  California (All     T               88 FR [Insert Federal
 [Central Coast DPS].                                  foothill yellow-                    Register page where
                                                       legged frogs in                     the document begins],
                                                       the Central Coast                   8/29/2023; 50 CFR
                                                       Range south of                      17.43(g).\4d\
                                                       San Francisco Bay
                                                       to San Benito and
                                                       Fresno Counties).
Frog, foothill yellow-legged     Rana boylii........  California (All     T               88 FR [Insert Federal
 [North Feather DPS].                                  foothill yellow-                    Register page where
                                                       legged frogs in                     the document begins],
                                                       the North Feather                   8/29/2023; 50 CFR
                                                       River watershed                     17.43(g).\4d\
                                                       largely in Plumas
                                                       and Butte
                                                       Counties).
Frog, foothill yellow-legged     Rana boylii........  California (All     E               88 FR [Insert Federal
 [South Coast DPS].                                    foothill yellow-                    Register page where
                                                       legged frogs in                     the document begins],
                                                       the Coast Range                     8/29/2023.
                                                       from Coastal
                                                       Monterey County
                                                       south to Los
                                                       Angeles County).
Frog, foothill yellow-legged     Rana boylii........  California (All     E               88 FR [Insert Federal
 [South Sierra DPS].                                   foothill yellow-                    Register page where
                                                       legged frogs in                     the document begins],
                                                       the Sierra Nevada                   8/29/2023.
                                                       Mountains south
                                                       of the American
                                                       River sub-basin
                                                       south to the
                                                       Transverse Range
                                                       in Kern County).
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


0
3. Amend Sec.  17.43 by adding a paragraph (g) to read as follows:


Sec.  17.43  Special rules--amphibians.

* * * * *
    (g) Foothill yellow-legged frog (Rana boylii), Central Coast 
Distinct Population Segment (DPS) and North Feather DPS.
    (1) Location. The Central Coast DPS and North Feather DPS of the 
foothill yellow-legged frog are shown on the map that follows:


[[Page 59726]]


Figure 1 to paragraph (g)
[GRAPHIC] [TIFF OMITTED] TR29AU23.001

    (2) Prohibitions. The following prohibitions that apply to 
endangered wildlife also apply to the Central Coast DPS and North 
Feather DPS of the foothill yellow-legged frog. Except as provided 
under paragraph (g)(3) 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 
species:
    (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 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.
    (3) Exceptions from prohibitions. In regard to the Central Coast 
DPS and North Feather DPS of the foothill yellow-legged frog, you may:
    (i) Conduct activities as authorized by a permit under Sec.  17.32.

[[Page 59727]]

    (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) Take incidental to an otherwise lawful activity caused by:
    (A) Forest management activities for the purposes of reducing the 
risk or severity of catastrophic wildfire, which include fuels 
reduction activities, non-emergency firebreak establishment or 
maintenance, and other non-emergency wildfire prevention and 
suppression activities that are in accordance with an established 
forest or fuels management plan that follow current State of California 
Forest Practice Rules, State fire codes, or local fire codes/ordinances 
as appropriate.
    (B) Habitat restoration efforts that are specifically designed to 
provide for the conservation of the foothill yellow-legged frog. These 
efforts must be part of and carried out in accordance with finalized 
conservation plans or strategies specifically identified for the 
foothill yellow-legged frog and include measures that minimize impacts 
to the North Feather DPS or Central Coast DPS. Habitat restoration 
efforts for other species that may not share habitat requirements 
(e.g., salmonid species) are not included in this exception.
    (C) Efforts to remove and clean up trespass cannabis cultivation 
sites and related water diversion infrastructure and restore areas to 
precultivation conditions.
    (D) Removal or eradication of nonnative animal species including, 
but not limited to, American bullfrogs, smallmouth bass, and nonnative 
crayfish species occurring within stream reaches unoccupied by the 
foothill yellow-legged frog within the range of the Central Coast DPS 
or North Feather DPS. Actions involving habitat disturbance or the use 
of chemical treatments are not included.
    (v) Possess and engage in other acts with unlawfully taken 
wildlife, as set forth at Sec.  17.21(d)(2) for endangered wildlife.

Wendi Weber,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-17675 Filed 8-28-23; 8:45 am]
BILLING CODE 4333-15-P