[Federal Register Volume 79, Number 190 (Wednesday, October 1, 2014)]
[Rules and Regulations]
[Pages 59140-59150]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-23305]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2014-0042; 4500030113]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List Rio Grande Cutthroat Trout as an Endangered or
Threatened Species
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list the Rio Grande cutthroat trout
(Oncorhynchus clarkii virginalis) as an endangered or threatened
species under the Endangered Species Act of 1973, as amended (Act).
After review of the best available scientific and commercial
information, we find that listing the Rio Grande cutthroat trout is not
warranted at this time, and, therefore, we are removing this species
from our candidate list. However, we ask the public to submit to us any
new information that becomes available concerning the status of the Rio
Grande cutthroat trout at any time.
DATES: The finding announced in this document was made on October 1,
2014.
ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R2-ES-2014-0042. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, New Mexico Ecological Services Field Office,
2105 Osuna Rd NE., Albuquerque, NM 87113. Please submit any new
information, materials, comments, or questions concerning this finding
to the above street address.
FOR FURTHER INFORMATION CONTACT: Wally ``J'' Murphy, Field Supervisor,
New Mexico Ecological Services Field Office (see ADDRESSES); telephone
505-346-2525; or facsimile 505-346-2542. If
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you use a telecommunications device for the deaf (TDD), please call the
Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires
that, for any petition to revise the Federal Lists of Endangered and
Threatened Wildlife and Plants that contains substantial scientific or
commercial information that listing the species may be warranted, we
make a finding within 12 months of the date of receipt of the petition.
In this finding, we will determine that the petitioned action is: (1)
Not warranted, (2) warranted, or (3) warranted, but the immediate
proposal of a regulation implementing the petitioned action is
precluded by other pending proposals to determine whether species are
endangered or threatened, and expeditious progress is being made to add
or remove qualified species from the Federal Lists of Endangered and
Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires
that we treat a petition for which the requested action is found to be
warranted but precluded as though resubmitted on the date of such
finding, that is, requiring a subsequent finding to be made within 12
months. We must publish these 12-month findings in the Federal
Register.
Previous Federal Actions
On February 25, 1998, we received a petition from the Southwest
Center for Biological Diversity requesting that the Rio Grande
cutthroat trout be listed as an endangered or threatened species. We
subsequently published a notice of a 90-day petition finding in the
Federal Register (63 FR 49062) on September 14, 1998, concluding that
the petition did not present substantial information indicating that
listing of the Rio Grande cutthroat trout may be warranted.
On June 9, 1999, the Southwest Center for Biological Diversity sued
the Service in regard to our September 14, 1998, 90-day petition
finding. While this litigation was pending, we received information
(particularly related to the presence of whirling disease in hatchery
fish in the wild) that led us to believe that further review of the
status of the subspecies was warranted. On November 8, 2001, the
Service and the Southwest Center for Biological Diversity entered into
a settlement agreement stipulating that the Service would initiate a
status review for the Rio Grande cutthroat trout; make a determination
on or before June 3, 2002; and shortly thereafter, publish our
determination in the Federal Register. On June 11, 2002, after
reviewing the best available scientific and commercial data, including
data related to the presence of whirling disease, we published a
determination that listing of Rio Grande cutthroat trout was not
warranted (67 FR 39936).
Subsequently, on February 25, 2003, the Center for Biological
Diversity (formerly Southwest Center for Biological Diversity), along
with several other organizations, sued the Service for the 2002
decision that the subspecies did not warrant listing under the Act. On
June 7, 2005, the district court ruled that our finding was not
arbitrary and capricious, but also required that we explain in more
detail our analysis of ``significant portion of the range.'' The court
ordered the Service to provide supplemental briefing discussing in more
detail our analysis of ``significant portion of the range.'' Following
submission of this briefing, on December 22, 2005, the Court ruled in
favor of the Service and upheld our interpretation of ``significant
portion of the range'' and determined that our evaluation of the Rio
Grande cutthroat trout's status under the listing criteria was not
arbitrary and capricious. Plaintiffs appealed this decision.
The appeal was pending with the Tenth Circuit Court of Appeals,
when other courts issued opinions in regard to decisions for other
species that required the Service to reexamine our legal position on
``significant portion of the range.'' On March 16, 2007, the Solicitor
of the Department of the Interior issued a formal legal opinion titled
``The Meaning of In Danger of Extinction Throughout All or a
Significant Portion of Its Range'' (M-37013, U.S. DOI 2007). Because of
this new formal legal opinion and because of our knowledge of changes
in status of some populations that we had previously defined as secure
in our 2002 review, the Service initiated a new status review. We
subsequently published notices seeking new information concerning the
status of Rio Grande cutthroat trout on May 22, 2007 (72 FR 28664) and
August 16, 2007 (72 FR 46030). On May 14, 2008 (73 FR 27900), we found
that the Rio Grande cutthroat trout warranted listing as an endangered
or threatened species under the Act based on threats to the subspecies
related to population fragmentation and isolation, small population
size, nonnative trout, drought, and fire. However, the Service
determined that developing a proposed rule to list the Rio Grande
cutthroat trout as endangered or threatened at that time was precluded
by other, higher priority listing actions. The subspecies became a
candidate for listing at that time.
On September 9, 2011, the Service entered into a settlement
agreement regarding species on the candidate list in multi-district
litigation (MDL settlement agreement; Endangered Species Act Section 4
Deadline Litigation, No. 10-377 (EGS), MDL Docket No. 2165 (D.D.C. May
10, 2011)). Per the MDL settlement agreement, the Service is required
to submit a proposed rule or a not warranted 12-month finding to the
Federal Register for Rio Grande cutthroat trout in Fiscal Year 2014,
which ends September 30, 2014. This 12-month finding fulfills that
requirement of the MDL settlement agreement.
Summary of Biological Status
We completed the Species Status Assessment Report for the Rio
Grande Cutthroat Trout (SSA Report; Service 2014a, entire), which is
available online at http://www.regulations.gov, Docket No. FWS-R2-ES-
2014-0042. The SSA Report documents the results of the comprehensive
biological status review for the Rio Grande cutthroat trout
(Oncorhynchus clarkii virginalis) and provides an account of the
subspecies' overall viability and thus extinction risk through a
forecasting of the number and distribution of surving populations in
the future (Service 2014a, entire). In the SSA Report we summarized the
relevant biological data and a description of past, present, and likely
future risk factors (causes and effects) and conducted a new analysis
of the viability of the subspecies. The SSA Report provides the
scientific basis that informs our regulatory decision regarding whether
this subspecies should be listed as endangered or threatened under the
Act. This decision involves the application of standards within the
Act, its implementing regulations, and Service policies (see Finding).
The SSA Report contains the risk analysis on which this finding is
based, and the following discussion is a summary of the results and
conclusions from the SSA Report.
Rio Grande cutthroat trout (a subspecies of cutthroat trout)
inhabit high-elevation streams in New Mexico and southern Colorado,
where they need clear, cold, highly oxygenated water; clean gravel
substrates; a network of pools and runs; and an abundance of food
(typically aquatic and terrestrial invertebrates) to complete their
life history. The subspecies needs multiple resilient populations
widely distributed across its range to maintain its persistence into
the future and to avoid extinction. Resilient populations require long,
continuous, suitable stream
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habitats to support large numbers of individuals and to withstand
stochastic events; the populations should be free from the impacts of
nonnative trout. The resilient populations (the term resiliency is
defined below) should be distributed in each of the four geographic
management units (GMUs) where the subspecies currently occurs. This
distributional pattern will provide redundancy and representation
(these terms are defined below) to increase the probability that the
subspecies will withstand future catastrophic events and maintain
future adaptive capacity in terms of genetic and ecological diversity
(Service 2014a, Table ES-1). The likelihood of the Rio Grande cutthroat
trout's persistence depends upon the number of populations, its
resilience to threats, and its distribution. As we consider the future
viability of the subspecies, more populations with greater resiliency
and wider geographic distributions are associated with higher overall
subspecies viability.
The Rio Grande cutthroat trout historically occurred in New Mexico
and southern Colorado. Its distribution has been divided into five GMUs
reflecting major hydrologic divisions. The subspecies no longer occurs
in one GMU, the Caballo GMU, where only one population was historically
known. The remaining four GMUs are managed by the States of Colorado
and New Mexico and other agencies as separate units to maintain genetic
and ecological diversity within the subspecies where it exists and to
ensure representation of the subspecies across its historical range.
GMUs were not created to necessarily reflect important differences in
genetic variability, although fish in the Pecos and Canadian GMUs do
exhibit some genetic differentiation from those in the Rio Grande basin
GMUs. From a rangewide perspective, multiple Rio Grande cutthroat trout
populations should be dispersed throughout the various GMUs to maintain
subspecies viability and to reduce the likelihood of extinction.
Currently the subspecies is distributed in 122 populations across
the four GMUs (ranging from 10 to 59 populations per GMU), and most of
the populations are isolated from other populations. The total amount
of currently occupied stream habitat is estimated to be about 11
percent of the historically occupied range. This large decline in
distribution and abundance is primarily due to the impacts of the
introduction of nonnative trout. Nonnative rainbow trout (O. mykiss)
and other nonnative subspecies of cutthroat trout invaded most of the
historical range of the Rio Grande cutthroat trout and resulted in
their extirpation because the nonnative trout readily hybridize with
Rio Grande cutthroat trout. In addition, brown trout (Salmo trutta) and
brook trout (Salvelinus fontinalis) have also displaced Rio Grande
cutthroat trout in some historical habitats through competition and
predation pressures. We evaluated the current condition of the 122
populations and categorized the condition of each population based on
the absence of nonnative trout, the effective population size, and the
occupied stream length. Fifty-five populations were in either the
``best'' or ``good'' condition in this categorization. Table ES-2 in
the SSA Report identifies the number of populations placed in each
category by GMU (see Service 2014a, Chapter 3 for a description of the
categories).
We next reviewed the past, current, and future factors that could
affect the persistence of Rio Grande cutthroat trout populations. Seven
risk factors were evaluated in detail to estimate their individual and
cumulative contributions to the overall risk to the subspecies'
viability. We focused on these seven factors because they were found to
potentially have population-level effects on the subspecies (Service
2014a, Chapter 4, Appendix B, and Appendix C). The seven factors were:
(1) Demographic Risk: Small population sizes are at greater risk
from inbreeding, demographic fluctuations, and reduced genetic
diversity, and they are more vulnerable to extirpation from other risk
factors.
(2) Hybridizing Nonnative Trout: Nonnative rainbow and other
cutthroat trout subspecies have historically been introduced throughout
the range of Rio Grande cutthroat trout for recreational angling, and
they are known to readily hybridize with Rio Grande cutthroat trout.
Climate change may exacerbate this risk factor as warmer waters may
make high-elevation habitats more susceptible to invasion by rainbow
trout.
(3) Competing Nonnative Trout: Brook and brown trout compete with
Rio Grande cutthroat trout for food and space, and larger adults will
prey upon young Rio Grande cutthroat trout.
(4) Wildfire: Ash and debris flows that occur after a wildfire can
eliminate populations of fish from a stream, and wildfires within the
range of Rio Grande cutthroat trout have depressed or eliminated fish
populations. As drought frequency increases due to climate change, dry
forests are more likely to burn and burn hotter than they have in the
past.
(5) Stream Drying: Drying of streams occupied by Rio Grande
cutthroat trout populations may occur as a result of drought or, in a
few cases, water withdrawals. Drought frequency is expected to increase
as a result of climate change due to a combination of increased summer
temperatures and decreased precipitation.
(6) Disease: Whirling disease damages cartilage, killing young fish
or causing infected fish to swim in an uncontrolled whirling motion,
making it impossible to avoid predation or feed.
(7) Water Temperature Changes: Changes in air temperature and
precipitation patterns expected from climate change could result in
elevated stream temperatures that make habitat unsuitable for Rio
Grande cutthroat trout to complete their life history.
We considered other potential factors as well, including hydrologic
changes related to future climate change, effects to habitat related to
land management, and angling. Our review of the best available
information did not demonstrate a relationship between hydrologic
changes and the potential negative effects on the subspecies to allow
for reasonably reliable conclusions; therefore, we did not consider
that factor further. We found that land management activities are not
likely to have a measurable population-level effect on the subspecies,
and angling was also not found to be a substantial factor affecting the
subspecies. Therefore, these factors were not evaluated further in our
analysis (Service 2014a, Chapter 4).
We included future management actions as an important part of our
overall assessment. The Rio Grande Cutthroat Trout Conservation Team
(Conservation Team) is composed of biologists from Colorado Parks and
Wildlife (CPW), New Mexico Department of Game and Fish (NMDGF), U.S.
Bureau of Land Management (BLM), U.S. Forest Service (USFS), National
Park Service (NPS), Mescalero Apache Nation, Jicarilla Apache Nation,
Taos Pueblo, and the Service. The Conservation Team developed the
Conservation Agreement and Strategy in 2013 (revised from the previous
Conservation Agreements in 2003 and 2009), which formalized many
ongoing management actions. The Conservation Agreement and Strategy
includes activities such as stream restorations, barrier construction
and maintenance, nonnative species removals, habitat improvements,
public outreach, and database management. Over the 10-year life of the
Conservation Agreement and Strategy, the Conservation Team has
committed to
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restoration of between 11 and 20 new Rio Grande cutthroat trout
populations to historical habitat. We included these activities in our
analysis of the future status of the subspecies over the next 10 years
(see PECE Analysis, below) and projected various scenarios of active
management beyond that.
We developed a species status assessment model to quantitatively
incorporate the risks of extirpation from the seven risk factors listed
above (including cumulative effects) in order to estimate the future
probability of persistence of each extant population of Rio Grande
cutthroat trout. We used this model to forecast the future status of
the Rio Grande cutthroat trout in a way that addresses viability in
terms of the subspecies' resiliency, redundancy, and representation. As
a result, we developed two distinct modules. Module 1 estimates the
probability of persistence for each Rio Grande trout population by GMU
for three future time periods (2023, 2040, and 2080) under a range of
conditions, and Module 2 estimates the number of surviving populations
by GMU for the three future time periods under several scenarios
related to future management actions and the effects of climate change.
A detailed explanation of the methodology used to develop the model is
provided in Appendix C of the SSA Report (Service 2014a, Appendix C),
and the results are summarized in Chapter 5 (Service 2014a, Chapter 5).
We used the results of this analysis to describe the viability of
the Rio Grande cutthroat trout (viability is the ability of a species
to persist over time and thus avoid extinction; ``persist'' means that
the species is expected to sustain populations in the wild beyond the
end of a specified time period) by characterizing the status of the
subspecies in terms of its resiliency, redundancy, and representation.
Resiliency is having sufficiently large populations for the
subspecies to withstand stochastic events. We measured resiliency at
the population scale for the Rio Grande cutthroat trout by quantifying
the persistence probability of each extant population under a range of
assumed conditions. As expected because of the way the status
assessment model was developed to forecast linearly increasing risks
over time, all of the population persistence probabilities decrease in
our three time periods. Our results do not necessarily mean that any
one population will, in fact, be extirpated by 2080; they simply
reflect the risks that we believe the populations face due to their
current conditions and the risk factors influencing their resiliency.
Rangewide, the resiliency of the subspecies has declined
substantially due to the large decrease in overall distribution in the
last 50 years. In addition, the remnant Rio Grande cutthroat trout
populations are now mostly isolated to headwater streams due to the
fragmentation that has resulted from the historical, widespread
introduction of nonnative trout across the range of Rio Grande
cutthroat trout. Therefore, if an extant population is extirpated due
to a localized event, such as a wildfire and subsequent debris flow,
there is little to no opportunity for natural recolonization of that
population. This reduction in resiliency results in a lower probability
of persistence for the subspecies as a whole. To describe the remaining
resiliency of the subspecies, we evaluated the individual populations
in detail to understand the subspecies' overall capacity to withstand
stochastic events.
Redundancy is having a sufficient number of populations for the
subspecies to withstand catastrophic events. For the Rio Grande
cutthroat trout, we measured redundancy based our forecasting of the
number of populations persisting across the subspecies' range. The
results suggest that, depending on the particular scenario related to
risk factors and restoration efforts, the overall number of populations
may decline to some extent by 2080 (Service 2014a, Table ES-1, Column
4). We are focusing on the estimates for 2080, because if the
subspecies has sufficient redundancy by 2080, it will also have
sufficient redundancy in the more recent time periods. Rangewide there
are currently 122 populations, and we forecast between 50 and 132
populations surviving in 2080 (with an intermediate forecast of 68
populations). The wide range in the estimated number of surviving
populations is due to the various projections of management and climate
change intensity. Some GMUs may decline more than others; for example,
our forecasts suggest the Lower Rio Grande GMU may have the largest
decline. We estimate the current 59 populations in this GMU could be
between 21 and 47 populations by 2080 (with an intermediate forecast of
28 populations). The GMU with the least populations, the Canadian GMU,
is forecasted to change from 10 current populations to between 3 and 14
populations by 2080 (with an intermediate forecast of 6 populations).
Representation is having the breadth of genetic and ecological
diversity of the subspecies to adapt to changing environmental
conditions. For the Rio Grande cutthroat trout, we evaluated
representation based on the extent of the geographical range expected
to be maintained in the future as indicated by the populations
occurring within each GMU for a measure of ecological diversity. For
genetic diversity, there are important genetic differences between the
Rio Grande basin populations and the populations in the Canadian and
Pecos GMUs (though the Pecos and Canadian GMUs are not genetically
different from each other). The variation in persistence probabilities
is distributed across the GMU so that none of the risk is particularly
associated with any particular geographic area within the GMU.
Combined, the Canadian and Pecos GMUs are forecasted to have 8 to 30
populations surviving in 2080 (with an intermediate forecast of 14
populations).
We used the best available information to forecast the likely
future condition of the Rio Grande cutthroat trout. Our goal was to
describe the viability of the subspecies quantitatively in a way that
characterizes the needs of the subspecies in terms of resiliency,
redundancy, and representation. We considered the possible future
condition of the subspecies out to about 65 years from the present (see
discussion regarding foreseeable future, below, in the Threatened
Species Throughout Range section). We considered nine different
scenarios that spanned a range of potential conditions that we believe
are important influences on the status of the subspecies. Our results
describe a range of possible conditions in terms of the probability of
persistence of individual populations across the GMUs and a forecast of
the number of populations surviving in each GMU.
Although we evaluated nine different scenarios in our assessment,
for this finding we report the foreseeable worse case and best case
results that show the full range of outcomes. In each of the relevant
conclusions, we focus on the foreseeable worse case results. Logically,
if the subspecies does not warrant listing under our worst-case
scenario, the eight remaining scenarios will also not warrant listing
the subspecies. We also provide in this finding the best case results
of each scenario for each of the relevant conclusions. This provides a
context for the range of possible outcomes for the future populations
of the subspecies.
Considering the worst case scenario allowed us to view the
viability of the subspecies under conditions of low management and
severe climate change, which are aspects of the model with high
uncertainty. None of our ``worst case scenario'' forecasts results in a
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predicted loss of all of the populations within any of the GMUs.
Therefore, at a minimum, our results suggest the subspecies will have
persisting populations in 2080 across its range. Most of the scenarios
generally show a declining number of populations over time. However,
the rate of this decline, or whether it occurs at all, depends largely
on the likelihood of future management actions occurring, the most
important of which are the future restoration and reintroduction of
populations within the historical range and the control of nonnative
trout. While other factors are important to each population, the future
management efforts will probably determine the future viability of the
Rio Grande cutthroat trout. These conservation efforts were an
important consideration in the SSA analysis.
PECE Analysis
The Service's 2003 Policy for Evaluation of Conservation Efforts
When Making Listing Decisions (PECE) provides guidance on how to
evaluate conservation efforts that have not yet been fully implemented
or have not yet demonstrated effectiveness (68 FR 15100, March 28,
2003). The purpose of PECE is to ensure consistent and adequate
evaluation of recently formalized conservation efforts when making
listing decisions. The policy presents criteria for evaluating the
certainty of implementation and the certainty of effectiveness for such
conservation efforts. We evaluated two formalized conservation efforts
and their specific conservation measures under PECE (see PECE
Evaluation, Service 2014b, entire): the Conservation Agreement and
Strategy and the Vermejo Park Ranch Candidate Conservation Agreement
with Assurances (Vermejo CCAA). We found the specific conservation
measures in each of the formalized conservation efforts to have high
levels of certainty of implementation and effectiveness and both were
considered as part of the basis for our listing determination for the
Rio Grande cutthroat trout. Below is a brief summary of each effort,
and more detail is provided in our separate PECE analysis (Service
2014b, entire).
Conservation Agreement and Strategy
The Conservation Agreement and Strategy for the Conservation of Rio
Grande Cutthroat Trout was signed in 2013 by NMDGF, CPW, USFS, NPS,
BLM, Mescalero Apache Nation, Jicarilla Apache Nation, Taos Pueblo, and
the Service. The 2013 Conservation Agreement and Strategy was a
revision to the Conservation Agreement that was originally signed in
2003. The measures in the Conservation Agreement and Strategy are made
up of cooperative efforts by the parties to develop and implement the
necessary conservation measures for the Rio Grande cutthroat trout to
have sufficient resiliency, representation, and redundancy to provide
for long-term viability. Conservation measures include:
(1) Identify and characterize all Rio Grande cutthroat trout
conservation populations and occupied habitat. Characterization
includes gathering data on Rio Grande cutthroat trout density, length
of occupied habitat, genetic status, and habitat quality.
(2) Secure and enhance conservation populations.
(3) Restore populations.
(4) Secure and enhance watershed conditions.
(5) Public outreach.
(6) Data sharing.
(7) Coordination.
Throughout the 10-year life of the Conservation Agreement and
Strategy, the parties have committed to restoring 11 to 20 new
populations of Rio Grande cutthroat trout rangewide. In our PECE
analysis, we found that the conservation efforts in the Rio Grande
Cutthroat Trout Conservation Agreement and Strategy have a high level
of certainty of implementation and effectiveness because of the
demonstrated ability of the participants in carrying out an effective
conservation program for this subspecies. Therefore, we considered
these efforts as part of the basis for our listing determination for
the Rio Grande cutthroat trout under the Act.
Vermejo CCAA
The goal of the Vermejo CCAA, signed in 2013, is to facilitate and
promote the conservation and restoration of the Rio Grande cutthroat
trout on certain non-Federal lands owned by Vermejo Park Ranch, LLC.
Vermejo Park Ranch consists of 590,823 acres (2,391 square kilometers)
in Costilla County, Colorado, and Taos County, New Mexico, managed for
conservation, hunting, and fishing. Vermejo Park Ranch is implementing
the conservation measures specified in the Vermejo CCAA and has
received assurances from the Service that if the Rio Grande cutthroat
trout is listed under the Act, no further conservation measures will be
required. Conservation measures being implemented by Vermejo Park Ranch
include nonnative trout removal, Rio Grande cutthroat trout
reintroductions, and increasing existing populations so they are
capable of migrating among tributaries. Overall, the project
encompasses the restoration of approximately 190 kilometers (118 miles)
of stream habitat, and to date nearly 100 kilometers (62 miles) of
restoration have been completed and are being monitored. In our PECE
analysis, we found that the conservation efforts in the Vermejo CCAA
have a high level of certainty of implementation and effectiveness
because of the demonstrated ability of the Vermejo Park Ranch for
carrying out effective conservation actions for the subspecies.
Therefore, we considered these conservation efforts as part of the
basis for our listing determination for the Rio Grande cutthroat trout.
Finding
Standard for Review
Section 4 of the Act, and its implementing regulations at 50 CFR
part 424, set forth the procedures for adding species to the Federal
Lists of Endangered and Threatened Wildlife and Plants. Under section
4(b)(1)(a), the Secretary is to make endangered or threatened
determinations required by subsection 4(a)(1) solely on the basis of
the best scientific and commercial data available to her after
conducting a review of the status of the subspecies and after taking
into account conservation efforts by States or foreign nations. The
standards for determining whether a species is endangered or threatened
are provided in section 3 of the Act. An endangered species is any
species that is ``in danger of extinction throughout all or a
significant portion of its range.'' A threatened species is any species
that is ``likely to become an endangered species within the foreseeable
future throughout all or a significant portion of its range.'' Per
section 4(a)(1) of the Act, in reviewing the status of the species to
determine if it meets the definition of endangered or of threatened, we
determine whether any species is an endangered species or a threatened
species because of any of the following five factors: (A) The present
or threatened destruction, modification, or curtailment of its habitat
or range; (B) overutilization for commercial, recreational, scientific,
or educational purposes; (C) disease or predation; (D) the inadequacy
of existing regulatory mechanisms; and (E) other natural or manmade
factors affecting its continued existence.
Until recently the Service has presented its evaluation of
information under the five listing factors in an outline format,
discussing all of the information relevant to any given factor and
providing a factor-specific conclusion before moving to the next
factor. However, the Act does not
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require findings under each of the factors, only an overall
determination as to the species' status (for example, endangered
species, threatened species, or not warranted). Ongoing efforts to
improve the efficiency and efficacy of the Service's implementation of
the Act have led us to present this information in a different format
that we find leads to greater clarity in our understanding of the
science, its uncertainties, and our application of our statutory
framework to that science. Therefore, while the presentation of
information in this document differs from past practice, it differs in
format only. We have evaluated the same body of information that, in
the past, we have discussed under an outline of the five listing
factors. In this analysis, we are applying the same information
standard, and we are applying the same statutory framework in reaching
our conclusions and ultimate determination of the status of the
subspecies under the Act.
Summary of Analysis
The biological information we reviewed and analyzed as the basis
for our findings is documented in the Rio Grande Cutthroat Trout
Species Status Assessment Report (Service 2014a, entire), a summary of
which is provided in the background of this finding. The projections
for the number of future persisting populations are based on the
Species Status Assessment Model (SSA Model; Service 2014a, Chapter 5
and Appendix C), which incorporates the potential risk factors (in
other words, threats) that were found to have possible population-level
effects. The risk factors we evaluated in detail are demographic risk
(Factor E from the Act), nonnative trout (Factors C and E), wildfire
(Factor A), stream drying (Factor A), disease (Factor C), and water
temperature changes (Factor A). For four of the factors (hybridizing
nonnative trout, wildfire, stream drying, and water temperature
changes), we also considered the exacerbating effects of climate
change. We reviewed, but did not evaluate in further detail because of
a lack of population-level effects, the effects of land management
activities and hydrologic changes (Factor A), and recreational angling
(Factor B).
The overall results of the status assessment found that the best
available information indicates that large declines (approximately 89
percent loss) in the distribution and abundance of Rio Grande cutthroat
trout have occurred in the past 50 years or so due mainly to the
impacts from introduced nonnative trout. This declining trend has been
abated in recent years to a large extent due to management efforts to
control nonnative trout and limit new introductions and the spread of
nonnative trout. However, the results of the past impacts have left the
Rio Grande cutthroat trout in a remnant of its former habitat, which is
now primarily high-elevation headwater streams. The purpose of the
status assessment was to characterize the future viability of the
subspecies in the face of this reduced distribution and the ongoing
factors that put populations at risk of extirpation.
In the SSA Report, we described the viability of the Rio Grande
cutthroat trout in terms of redundancy, representation, and resiliency
(Service 2014a, Chapter 5). These characteristics have all been reduced
in the subspecies because of the historical declines in its
distribution and abundance. In addition, the reduction in population
sizes and the isolated nature of most remaining populations makes many
of the potential stressors to the Rio Grande cutthroat trout more
significant than they would have been historically. This is because
small populations are more susceptible to extirpation from negative
events, whether those events are natural or human-caused. In addition,
in the event of a local extirpation due to a negative stochastic event,
isolated populations are unable to be recolonized by natural dispersal
from nearby populations. Therefore, the Rio Grande cutthroat trout has
an overall reduced viability compared to historical conditions.
Our forecasts take into consideration a range of the likely number
of populations that could be restored in the future through work of the
agencies under the multi-agency Conservation Agreement and Strategy.
Numerous conservation efforts are ongoing for Rio Grande cutthroat
trout. The conservation measures for the Conservation Agreement and
Strategy and the Vermejo CCAA are evaluated in the PECE analysis
(Service 2014b) discussed above. The formal agreements extend for 10
years, but in the case of the Conservation Agreement and Strategy, in
particular, we expect efforts to continue further into the future. We
cannot predict the number and type of efforts that will be performed in
the future with as much accuracy as the Conservation Agreement and
Strategy specifies for the next 10 years. However, given the history of
the Conservation Team and the motivation of the States in the
conservation of this subspecies (Service 2014b), we expect management
efforts to continue past the life of the Conservation Agreement and
Strategy, either formally (through renewal of the Conservation
Agreement and Strategy) or informally. As such, we have included
varying levels of conservation efforts in the different scenarios of
our model forecasting.
Application of Analysis to Determinations
Our status assesment characterized Rio Grande cutthroat trout
viability (future persistence) in terms of number and distribution of
populations expected to persist through 2080. These outputs form the
basis for our determinations under the Act. Because of uncertainty,
mainly related to climate change and the level of future conservation
efforts, our forecasts include a variety of scenarios. For these
findings, we refer to our results under the best and worst case
scenarios over two time horizons: 2023 and 2080. The fundamental
question before the Service is whether the projections of extinction
risk, described in terms of the number of future populations and their
distribution (taking into account the risk factors and their effects on
those populations), indicate that the subspecies warrants protection as
endangered or threatened under the Act. The lower the number and
smaller the distribution of the persisting populations, the higher the
extinction risk and lower the overall viability. In making our
determinations, we focused on the worst case scenario because, if the
worst case scenario does not rise to a level for which the subspecies
meets the definition of an endangered or a threatened species, then the
more optimistic forecasts are considerably better and likewise would
not warrant an endangered or threatened conclusion. We also included
the best case scenario outcome in order to provide context of the
likely range of the number of persisting populations of the subspecies.
As described in the determinations below, we first evaluated
whether the Rio Grande cutthroat trout is in danger of extinction
throughout its range now (an endangered species). We then evaluated
whether the subspecies is likely to become in danger of extinction
throughout its range in the foreseeable future (a threatened species).
We considered future voluntary conservation efforts in the information
used in these determinations, consistent with PECE. We finally
considered whether the Rio Grande cutthroat trout is an endangered or
threatened species in a significant portion of its range (SPR).
[[Page 59146]]
Endangered Species Throughout Range
Standard
Under the Act, an endangered species is any species that is ``in
danger of extinction throughout all or a significant portion of its
range.'' Because of the fact-specific nature of listing determinations,
there is no single metric for determining if a species is currently in
danger of extinction. We used the best available scientific and
commercial information to evaluate the viability (and thus risk of
extinction) for the Rio Grande cutthroat trout to determine if it meets
the definition of an endangered species. In this finding, we used a
projection of the number and distribution of populations to measure the
Rio Grande cutthroat trout's viability and then determine the
subspecies' status under the Act.
Evaluation and Finding
Our review found that there are currently 122 existing populations
of the Rio Grande cutthroat trout in four GMUs. We consider each of
these populations genetically pure enough to be Rio Grande cutthroat
trout; that is, each population has 90 percent or more of the native
Rio Grande cutthroat trout genes. To assess the current status of these
populations, we sorted each of them into four categories to consider
their current status, which was based on effective population size,
occupied stream length, presence of competing nonnative trout, and
presence of hybridizing nonnative trout. We categorized 55 of the
populations (45 percent) as currently in the best or good condition of
having no nonative trout, relatively large effective population sizes,
and relatively long occupied stream lengths (Service 2014a, pp. 14-15).
This current number of populations in the best or good condition
existing across the subspecies' range provides resiliency (45 percent
of populations considered sufficiently large to withstand stochastic
events), redundancy (55 populations spread across all four extant GMUs
to withstand catastrophic events), and representation (multiple
populations are persisting across the range of the subspecies to
maintain ecological and genetic diversity).
The Rio Grande cutthroat trout also historically occurred in a
fifth GMU--the Caballo GMU. We only know of one historical population
in this GMU, which was extirpated more than 30 years ago. With only one
population, this area would not have significantly contributed to the
resiliency and redundancy of the subspecies. However, it could have had
some important genetic or ecological diversity that would have
contributed to the adaptive capacity of the subspecies. Losing this
population likely lowered the overall viability of the subspecies but
would not be a substantial enough impact rangewide to meaningfully
increase the overall risk of extinction of the Rio Grande cutthroat
trout.
To further consider the status of the Rio Grande cutthroat trout,
we analyzed the condition of the subspecies over the next 10 years to
evaluate its viability. In 2023, we projected an estimated range of
between 104 and 131 populations will persist under worst case and best
case scenarios, respectively. According to our forecasts, these
populations would be distributed throughout the subspecies' range, with
multiple populations persisting in all four of the currently extant
GMUs (see Service 2014a, pp. 44-45 for complete results). Therefore,
because this worst case estimate of the number and distribution of
populations provides resiliency, representation, and redundancy for the
subspecies, we conclude the subspecies does not meet the definition of
an endangered species under the Act. Although the subspecies has
experienced substantial reduction from its historical distribution, the
number of Rio Grande cutthroat trout populations currently persisting
and expected to persist in the next 10 years across its range does not
put the subspecies in danger of extinction.
Threatened Species Throughout Range
Having found that the Rio Grande cutthroat trout is not an
endangered species throughout its range, we next evaluated whether the
subspecies is a threatened species throughout its range.
Standard
Under the Act, a threatened species is any species that is ``likely
to become an endangered species within the foreseeable future
throughout all or a significant portion of its range.'' The foreseeable
future refers to the extent to which the Secretary can reasonably rely
on predictions about the future in making determinations about the
future conservation status of the species (U.S. Department of Interior,
Solicitor's Memorandum, M-37021, January 16, 2009). A key statutory
difference between a threatened species and an endangered species is
the timing of when a species may be in danger of extinction, either now
(endangered species) or in the foreseeable future (threatened species).
Evaluation and Finding
In considering the foreseeable future, our analysis used two
timeframes to forecast the status of the Rio Grande cutthroat trout as
measured by the number of possible surviving populations based on the
risk factors and conservation efforts the subspecies is facing. We
forecasted out to the years 2040 (about 25 years from present) and 2080
(about 65 years from present). We based these timeframes on the outputs
of downscaled climate forecasting models that often project climate
scenarios to the year 2080. Since potential effects of climate change
were important considerations in our status assessment, it was
necessary to consider a long enough timeframe to adequately evaluate
those potential effects. The 2080 timeframe represents about 13 to 21
Rio Grande cutthroat trout generations and is a reasonably long time to
consider for potential future effects of stressors on populations of
the subspecies. This timeframe also represents our outermost estimate
for forecasting, where our confidence decreases in our ability to
forecast future environmental conditions related to the risk factors
evaluated and to the responses of Rio Grande cutthroat trout
populations.
To assist us in evaluating the status of the subspecies in the
foreseeable future, we considered the risk factors that we found to
have potential population-level effects over time. These future risk
levels were incorporated into our status assessment model to forecast
the number of surviving populations into the foreseeable future. We
increased the risk levels linearly over time to account for the
cumulative increase in the risks of chance events occurring in the
future. In addition, for four risk factors (hybridizing nonnative
trout, wildlife, stream drying, and water temperature) we provided a
further increase in risks over time to account for the potential
effects of climate change. We used our best professional judgment to
estimate the effects of increasing risks due to climate change. In
addition, because of the high uncertainty associated with climate
change we considered a ``moderate'' and a ``severe'' effect of climate
change. For the moderate climate change effect, we increased the risk
function over time by 5 percent for the 2040 forecast and 10 percent
for the 2080 forecast. For the severe climate change effect, we
increased the risk function over time by 20 percent for the 2040
forecast and 40 percent for the 2080 forecast, as explained in greater
detail in our SSA Report. We also included management activities in our
[[Page 59147]]
analysis of the future status of the subspecies over the next 10 years
(see PECE Analysis, above), and projected various scenarios of active
management beyond that.
In 2080, our model forecasted 50 to 132 populations will persist
rangewide under our worst and best case scenarios, respectively, with
multiple populations in all four of the currently extant GMUs (Service
2014a, pp. 44-48). Therefore, because this worst-case forecast of the
number and distribution of populations provides resiliency, redundancy,
and representation for the subspecies, we conclude the subspecies is
not likely to become in danger of extinction in the foreseeable future.
Therefore, we find that the subspecies does not meet the definition of
a threatened species under the Act.
Endangered or Threatened in a Significant Portion of the Range
Having found that the Rio Grande cutthroat trout is not an
endangered or threatened species throughout its range, we next
evaluated whether the subspecies warrants listing based on any
significant portion of the subspecies' range.
Standard
Under the Act and our implementing regulations, a species may
warrant listing if it is an endangered or a threatened species
throughout all or a significant portion of its range. The Act defines
``endangered species'' as any species which is ``in danger of
extinction throughout all or a significant portion of its range,'' and
``threatened species'' as any species which is ``likely to become an
endangered species within the foreseeable future throughout all or a
significant portion of its range.'' The term ``species'' includes ``any
subspecies of fish or wildlife or plants, and any distinct population
segment of any species of vertebrate fish or wildlife which interbreeds
when mature.'' We published a final policy interpretating the phrase
``significant portion of its range'' (79 FR 37578, July 1, 2014). The
final policy states that (1) if a species is found to be an endangered
or a threatened species throughout a significant portion of its range,
the entire species is listed as an endangered or a threatened species,
respectively, and the Act's protections apply to all individuals of the
species wherever found; (2) a portion of the range of a species is
``significant'' if the species is not currently an endangered or a
threatened species throughout all of its range, but the portion's
contribution to the viability of the species is so important that,
without the members in that portion, the species would be in danger of
extinction, or likely to become so in the foreseeable future,
throughout all of its range; (3) the range of a species is considered
to be the general geographical area within which that species can be
found at the time the Service or NMFS makes any particular status
determination; and (4) if a vertebrate species is an endangered or a
threatened species throughout an SPR, and the population in that
significant portion is a valid distinct population segment (DPS), we
will list the DPS rather than the entire taxonomic species or
subspecies.
The SPR policy is applied to all status determinations, including
analyses for the purposes of making listing, delisting, and
reclassification determinations. The procedure for analyzing whether
any portion is an SPR is similar, regardless of the type of status
determination we are making. The first step in our analysis of the
status of a species is to determine its status throughout all of its
range. If we determine that the species is in danger of extinction, or
likely to become so in the foreseeable future, throughout all of its
range, we list the species as an endangered (or threatened) species and
no SPR analysis will be required. If the species is neither an
endangered nor a threatened species throughout all of its range, we
determine whether the species is an endangered or a threatened species
throughout a significant portion of its range. If it is, we list the
species as an endangered or a threatened species, respectively; if it
is not, we conclude that listing the species is not warranted.
When we conduct an SPR analysis, we first identify any portions of
the species' range that warrant further consideration. The range of a
species can theoretically be divided into portions in an infinite
number of ways. However, there is no purpose to analyzing portions of
the range that are not reasonably likely to be significant and either
an endangered or a threatened species. To identify only those portions
that warrant further consideration, we determine whether there is
substantial information indicating that (1) the portions may be
significant and (2) the species may be in danger of extinction in those
portions or likely to become so within the foreseeable future.
Answering these questions in the affirmative is not a determination
that the species is an endangered or a threatened species throughout a
significant portion of its range--rather, it is a step in determining
whether a more detailed analysis of the issue is required. In practice,
a key part of this analysis is whether the threats are geographically
concentrated in some way. If the threats to the species are affecting
it uniformly throughout its range, no portion is likely to warrant
further consideration. Moreover, if any concentration of threats apply
only to portions of the range that clearly do not meet the biologically
based definition of ``significant'' (i.e., the loss of that portion
clearly would not be expected to increase the vulnerability to
extinction of the entire species), those portions will not warrant
further consideration.
If we identify any portions that may be both (1) significant and
(2) endangered or threatened, we engage in a more detailed analysis to
determine whether these standards are indeed met. The identification of
an SPR does not create a presumption, prejudgment, or other
determination as to whether the species in that identified SPR is an
endangered or a threatened species. We must go through a separate
analysis to determine whether the species is an endangered or a
threatened species in the SPR. To determine whether a species is an
endangered or a threatened species throughout an SPR, we will use the
same standards and methodology that we use to determine if a species is
an endangered or a threatened species throughout its range.
Depending on the biology of the species, its range, and the threats
it faces, it may be more efficient to address the ``significant''
question first, or the status question first. Thus, if we determine
that a portion of the range is not ``significant,'' we do not need to
determine whether the species is an endangered or a threatened species
there; if we determine that the species is not an endangered or a
threatened species in a portion of its range, we do not need to
determine if that portion is ``significant.''
Evaluation
Our SSA Report and supporting model (Service 2014a, Appendix C)
evaluated population persistence (i.e., resiliency), incorporating the
threats to the populations, within the four extant GMUs. Additionally,
our description of the viability of the subspecies considered
resiliency, representation, and redundancy in terms of the expected
persistence of future populations at the GMU spatial scale. Therefore,
our existing analysis quantitatively forecasts the future condition of
Rio Grande cutthroat trout in a way that addresses viability in terms
of the subspecies' resiliency, redundancy, and representation. Because
the analysis was conducted by GMU, we are able to use the model's
[[Page 59148]]
output to analyze whether there is a significant portion of the range
that is more vulnerable to extirpation than other parts of the range.
Therefore, the following evaluation first considers whether each of
the four extant GMUs may be significant under our definition of SPR. In
other words, we evaluated whether that GMU's contribution to the
viability of the Rio Grande cutthroat trout is so important that,
without the members in that GMU, the subspecies would be in danger of
extinction, or likely to become so in the foreseeable future,
throughout all of its range. For the GMUs that we determined could meet
this standard of significance, we then considered whether the
forecasted future condition of that GMU, based on our species status
assessment, would be an endangered or a threatened species.
Rio Grande Headwaters GMU--The Rio Grande Headwaters GMU contains
34 percent (41 of 122) of the extant Rio Grande cutthroat trout
rangewide populations. If the populations in this GMU were all
extirpated, the subspecies in the remainder of the range could be an
endangered or threatened species because of the effects to the
subspecies' viability due to a substantial reduction in redundancy
(loss of large number of populations from a large portion of the
range). Therefore, the Rio Grande Headwaters GMU could be significant
according to our definition of SPR under the Act.
We next evaluated whether the Rio Grande Headwaters GMU is
endangered or threatened. Our review found that there are currently 41
existing populations of the Rio Grande cutthroat trout in the Rio
Grande Headwaters GMU. To assess the current status of these
populations, we sorted each of them into four categories to consider
their current status, which was based on effective population size,
occupied stream length, presence of competing nonnative trout, and
presence of hybridizing nonnative trout. We categorized 19 of the 41
populations (46 percent) as currently in the best or good condition
(Service 2014a, pp. 14-15). This number of reasonably resilient
populations within this GMU provides resiliency (46 percent of
populations considered sufficiently large to withstand stochastic
events), redundancy (19 populations in the GMU to withstand
catastrophic events), and representation (multiple populations are
persisting within the GMU to maintain ecological and genetic
diversity).
To consider the current risk of extinction of the Rio Grande
cutthroat trout, we analyzed the condition of this potential SPR over
the next 10 years to evaluate its viability (and thus its risk of
extinction) and considered all threats with possible population-level
effects. In 2023, we projected 41 to 49 populations will persist in the
Rio Grande Headwaters GMU under our worst and best case scenarios,
respectively (Service 2014a, p. 46). Therefore, because the worst case
scenario forecast of the number and distribution of populations
provides resiliency, representation, and redundancy for the subspecies
in the Rio Grande Headwaters GMU, we conclude the subspecies does not
meet the definition of an endangered species under the Act.
Having found that the Rio Grande cutthroat trout is not endangered
in the Rio Grande Headwaters GMU, we next evaluated whether the
subspecies is threatened in this potential SPR. As with the subspecies
rangewide (and for the same reasons), we used about 65 years from
present, the year 2080, as the foreseeable future to consider whether
the potential SPR is likely to become an endangered species. We also
used the same rationale for future forecasting of persisting
populations. In 2080, we forecasted 21 to 55 populations will persist
in the Rio Grande Headwaters GMU under our worst and best case
scenarios, respectively (Service 2014a, p. 46). Therefore, because the
worst case scenario forecast of the number and distribution of
populations provides resiliency, representation, and redundancy for the
subspecies in the Rio Grande Headwaters GMU, we conclude the subspecies
does not meet the definition of a threatened species under the Act.
Lower Rio Grande GMU--The Lower Rio Grande GMU contains 48 percent
(59 of 122) of the extant Rio Grande cutthroat trout rangewide
populations. If the populations in this GMU were all extirpated, the
subspecies in the remainder of the range could be an endangered or
threatened species because of the effects to the subspecies' viability
due to a substantial reduction in redundancy (loss of large number of
populations from a large portion of the range). Therefore, the Lower
Rio Grande GMU could be significant according to our definition of SPR
under the Act.
We next evaluated whether the Lower Rio Grande GMU is endangered or
threatened. Our review found that there are currently 59 existing
populations of the Rio Grande cutthroat trout in the Rio Grande
Headwaters GMU. To assess the current status of these populations, we
sorted each of them into four categories to consider their current
status, which was based on effective population size, occupied stream
length, presence of competing nonnative trout, and presence of
hybridizing nonnative trout. We categorized 28 of the populations (47
percent) as currently in the best or good condition (Service 2014a, pp.
14-15). This number of populations in the best or good condition within
this GMU provides resiliency (47 percent of populations considered
sufficiently large to withstand stochastic events), redundancy (28
populations in the GMU to withstand catastrophic events), and
representation (multiple populations are persisting within the GMU to
maintain ecological and genetic diversity).
To consider the current risk of extinction of the Rio Grande
cutthroat trout, we analyzed the condition of this potential SPR over
the next 10 years to evaluate its viability (and thus its risk of
extinction) and considered all threats with possible population-level
effects. In 2023, we projected 43 to 51 populations will persist in the
Lower Rio Grande GMU under our worst and best case scenarios,
respectively (Service 2014a, p. 46). Therefore, because the worst case
scenario forecast of the number and distribution of populations
provides resiliency, representation, and redundancy for the subspecies
in the Lower Rio Grande Headwaters GMU, we conclude that the subspecies
does not meet the definition of an endangered species under the Act.
Having found that the Rio Grande cutthroat trout is not an
endangered species in the Lower Rio Grande GMU, we next evaluated
whether the subspecies is a threatened species in this potential SPR.
As with the subspecies rangewide (and for the same reasons), we used
about 65 years from present, the year 2080, as the foreseeable future
to consider whether the potential SPR is likely to become an endangered
species. We also used the same rationale for future forecasting of
persisting populations . In 2080, we projected 21 to 47 populations
will persist in the Lower Rio Grande GMU, respectively (Service 2014a,
p. 46). Therefore, because the worst case scenario forecast of the
number and distribution of populations provides resiliency,
representation, and redundancy for the subspecies in the Lower Rio
Grande GMU, we conclude that the subspecies does not meet the
definition of a threatened species under the Act.
Canadian GMU--The Canadian GMU contains a small percentage of the
existing populations: Currently 8 percent (10 of 122) of current Rio
Grande cutthroat trout populations occur in this GMU. If this GMU were
extirpated, there would be a decrease in overall viability of the
subspecies, as
[[Page 59149]]
there would be if any proportion of the populations were extirpated.
However, 112 populations would remain in the rest of the range, and the
subspecies would still have levels of redundancy, resiliency, and
representation for sufficient viability to persist into the future.
Although one GMU would no longer be contributing to the representation
of the subspecies based on ecological diversity, we are not aware of
any particular adaptive capacity of the subspecies represented in that
GMU. While there is unique genetic diversity within the combined
Canadian and Pecos GMUs, the Canadian GMU independently has not been
found to contain unique diversity. Therefore, the lower overall
viability resulting from the potential loss of only the Canadian GMU
would not lead the remaining portion of the subspecies' range to meet
the definition of an endangered or threatened species under the Act. As
such, the Canadian GMU is not found to be significant as we define SPR
under the Act. Therefore, the subspecies is not an endangered or
threatened species in the potential Canadian GMU SPR.
Pecos GMU--The Pecos GMU also contains a small percentage of the
existing populations: 10 percent (12 of 122) of current Rio Grande
cutthroat trout populations occur in this GMU. If the Pecos GMU were
extirpated, there would be a decrease in overall viability of the
subspecies, as there would be if any proportion of the populations were
extirpated. However, 110 populations would remain in the rest of the
range, and the subspecies would still have levels of redundancy,
resiliency, and representation for sufficient viability to persist into
the future. Although one GMU would no longer be contributing to the
representation of the subspecies based on ecological diversity, we are
not aware of any particular adaptive capacity of the subspecies
represented in that GMU. While there is unique genetic diversity within
the combined Canadian and Pecos GMUs, the Pecos GMU independently has
not been found to contain unique diversity. Therefore, the lower
overall viability resulting from the potential loss of only the Pecos
GMU would not lead the remaining portion of the subspecies' range to
meet the definition of an endangered or threatened species under the
Act. As such, the Pecos GMU is not significant as we define SPR under
the Act. Therefore, the subspecies is not an endangered or threatened
species in the potential Pecos GMU SPR.
Pecos and Canadian GMUs Combined--The combined Pecos and Canadian
GMUs contain a moderate percentage of the existing populations:
Currently 18 percent (22 of 122 populations) occur in these GMUs. If
the populations in these GMUs were to be extirpated, the loss of the
unique genetic diversity contained collectively in these two GMUs and
the loss of a sizable portion of the range could cause the subspecies
in the remainder of the range to be endangered or threatened.
Consequently, the Pecos and Canadian GMUs combined could meet the
definition of ``significant'' under the SPR policy. Therefore, we
evaluated whether the Rio Grande cutthroat trout is an endangered or a
threatened species in the potential SPR of the combined Pecos and
Canadian GMUs.
Our review found that there are currently 22 existing populations
of the Rio Grande cutthroat trout in the potential Pecos-Canadian SPR.
To assess the current status of these populations, we sorted each of
them into four categories to consider their current status, which was
based on effective population size, occupied stream length, presence of
competing nonnative trout, and presence of hybridizing nonnative trout.
We categorized eight of the populations (36 percent) as currently in
the best or good condition (Service 2014a, pp. 14-15). This number of
populations in the best or good condition within this potential SPR
provides resiliency (36 percent of populations considered sufficiently
large to withstand stochastic events), redundancy (eight populations
spread across the potential SPR to withstand catastrophic events), and
representation (multiple populations are persisting across the
potential SPR to maintain ecological and genetic diversity).
To consider the current risk of extinction of the Rio Grande
cutthroat trout, we analyzed the condition of this potential Pecos-
Canadian SPR over the next 10 years to evaluate its viability,
considering all threats with possible population-level effects. In
2023, we projected an estimated 19 to 30 populations will persist in
the potential Pecos-Canadian SPR under our worst and best case
scenarios, respectively (Service 2014a, p. 46). Therefore, because this
worst case estimate of the number and distribution of populations
provides resiliency, representation, and redundancy for the subspecies,
we conclude the potential Pecos-Canadian SPR is not in danger of
extinction and does not meet the definition of an endangered species
under the Act.
Having found that the Rio Grande cutthroat trout is not an
endangered species in the potential Pecos-Canadian SPR, we next
evaluated whether the subspecies is a threatened species in this
potential SPR. As with the subspecies rangewide (and for the same
reasons), we used about 65 years from present, the year 2080, as the
foreseeable future to consider whether the potential SPR is likely to
become an endangered species. We also used the same rationale for
future forecasting of persisting populations as discussed above under
the rangewide determinations. In 2080, we forecast 8 to 29 populations
will persist in the potential Pecos-Canadian SPR under worst and best
case scenarios, respectively (Service 2014a, p. 46). Therefore, because
the worst case estimate of the number and distribution of populations
provides resiliency, representation, and redundancy for the subspecies,
we conclude the potential Pecos-Canadian SPR is not likely to be in
danger of extinction in the foreseeable future and does not meet the
definition of a threatened species under the Act.
Rio Grande Headwaters and Lower Rio Grande GMUs Combined--The
combined Rio Grande Headwaters and Lower Rio Grande GMUs contain a
large proportion of the range: Currently 82 percent (100 of 122
populations) occur in these GMUs. If the populations in these GMUs were
to be extirpated, the loss of the unique genetic diversity contained
collectively in these two GMUs and the loss of a large portion of the
range could cause the subspecies in the remainder of the range to be
endangered or threatened. Consequently, this potential SPR could meet
the definition of ``significant'' under the SPR policy. Therefore, we
evaluated whether the Rio Grande cutthroat trout is an endangered or a
threatened species in the potential SPR of the combined Rio Grande
Headwaters and Lower Rio Grande GMUs.
Our review found that there are currently 100 existing populations
of the Rio Grande cutthroat trout in the potential Rio Grande
Headwaters-Lower Rio Grande SPR. To assess the current status of these
populations, we sorted each of them into four categories to consider
their current status, which was based on effective population size,
occupied stream length, presence of competing nonnative trout, and
presence of hybridizing nonnative trout. We categorized 47 of the
populations (47 percent) as currently in the best or good condition
(Service 2014a, p. 14-15). This number of populations in the best or
good condition within this potential Rio Grande Headwaters-Lower Rio
Grande SPR provides resiliency (47 percent of populations considered
sufficiently large to withstand stochastic events), redundancy (47
populations
[[Page 59150]]
spread across the potential SPR to withstand catastrophic events), and
representation (multiple populations are persisting across the
potential SPR to maintain ecological and genetic diversity).
To consider the current risk of extinction of the Rio Grande
cutthroat trout, we analyzed the condition of this potential Rio Grande
Headwaters-Lower Rio Grande SPR over the next 10 years to evaluate its
viability, considering all threats with possible population-level
effects. In 2023, we forecasted 84 to 101 populations will persist in
the potential Rio Grande Headwaters-Lower Rio Grande SPR under our
worst and best case scenarios, respectively (Service 2014a, p. 46).
Therefore, because the worst case scenario for the number and
distribution of populations provides resiliency, representation, and
redundancy for the subspecies, we conclude the potential Rio Grande
Headwaters-Lower Rio Grande SPR is not in danger of extinction and does
not meet the definition of an endangered species under the Act.
Having found that the Rio Grande cutthroat trout is not an
endangered species in the potential Rio Grande Headwaters-Lower Rio
Grande SPR, we next evaluated whether the subspecies is a threatened
species in this potential SPR. As with the subspecies rangewide (and
for the same reasons), we used about 65 years from present, the year
2080, as the foreseeable future to consider whether the potential SPR
is likely to become endangered. We also used the same rationale for
future forecasting of persisting populations as discussed above under
the rangewide determinations. In 2080, we forecasted 42 to 102
populations would persist in this potential SPR under our worst and
best case scenarios, respectively, with multiple populations in each
GMU (Service 2014a, p. 46). Therefore, because the worst case scenario
for the number and distribution of populations provides resiliency,
representation, and redundancy for the subspecies, we conclude the
potential Rio Grande Headwaters-Lower Rio Grande SPR is not likely to
be in danger of extinction in the foreseeable future and does not meet
the definition of a threatened species under the Act.
Finding: Not an Endangered or a Threatened Species Based on a SPR
We found two GMUs (Canadian and Pecos GMUs) did not meet our
definition of significant in the SPR policy. We found four portions of
the range that could meet our definition of significant under the SPR
policy: Rio Grande Headwaters GMU, Lower Rio Grande GMU, Pecos and
Canadian GMUs Combined, and Rio Grande Headwaters and Lower Rio Grande
GMUs Combined. However, none of these portions of the range was found
to meet the definition of an endangered or a threatened species under
the Act. As a result, none of the potential SPR categorizations result
in the subspecies meeting the definition of endangered or threatened
under the Act.
Summary
In conclusion, we find that the Rio Grande cutthroat trout is not
in danger of extinction throughout its range, nor is it likely to
become so in the foreseeable future. We also considered a number of
areas concerning the potential for the subspecies to be an endangered
or threatened species in a significant portion of its range. We found
that four areas could meet our definition of significant; however, none
of the potential SPRs was found to be in danger of extinction now or in
the foreseeable future. Therefore, we determine that the Rio Grande
cutthroat trout is not warranted for listing as an endangered or a
threatened species under the Act throughout its rangewide or in any
significant portion of its range.
We request that you submit any new information concerning the
status of, or threats to, the Rio Grande cutthroat trout to our New
Mexico Ecological Services Field Office (see ADDRESSES) whenever it
becomes available. New information will help us monitor the Rio Grande
cutthroat trout and encourage its conservation. If an emergency
situation develops for Rio Grande cutthroat trout, we will consider an
appropriate response under the Act.
References Cited
A complete list of references cited is available in Appendix D of
the SSA Report (Service 2014a, Appendix D), available online at http://www.regulations.gov, under Docket Number FWS-R2-ES-2014-0042. The
Service's PECE Evaluation (Service 2014b) is also available online at
http://www.regulations.gov, under Docket Number FWS-R2-ES-2014-0042.
Authors
The primary authors of this notice are the staff members of the
Service's New Mexico Ecological Services Field Office and Southwest
Regional Office.
Authority
The authority for this section is section 4 of the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: September 23, 2014.
David Cottingham,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2014-23305 Filed 9-30-14; 8:45 am]
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