[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