[Federal Register Volume 80, Number 66 (Tuesday, April 7, 2015)]
[Proposed Rules]
[Pages 18741-18772]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2015-07766]
[[Page 18741]]
Vol. 80
Tuesday,
No. 66
April 7, 2015
Part III
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; 12-Month Finding on a
Petition To List Humboldt Marten as an Endangered or Threatened
Species; Proposed Rule
Federal Register / Vol. 80 , No. 66 / Tuesday, April 7, 2015 /
Proposed Rules
[[Page 18742]]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R8-ES-2011-0105; 4500030113]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List Humboldt Marten 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 previously classified
subspecies Humboldt marten (Martes americana humboldtensis), or the
(now-recognized) subspecies of Humboldt marten (Martes caurina
humboldtensis), or the Humboldt marten distinct population segment
(DPS) of the Pacific marten (M. caurina) as an endangered or threatened
species under the Endangered Species Act of 1973, as amended (Act). The
petition and this finding also address populations of marten from
coastal Oregon, which recent genetic analyses indicate are likely to be
the same entity as the current classification of Humboldt marten. We
recognize a coastal DPS of the Pacific marten (which includes coastal
Oregon populations of marten and the current classification of Humboldt
marten) and find that this DPS is not warranted for listing at this
time. However, we ask the public to submit to us any new information
that becomes available concerning the stressors that may be impacting
the coastal DPS of Pacific marten or its habitat at any time.
DATES: The finding announced in this document was made on April 7,
2015.
ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R8-ES-2011-0105. 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, Arcata Fish and Wildlife Office, 1655
Heindon Road, Arcata, CA 95521. Please submit any new information,
materials, comments, or questions concerning this finding to the above
street address.
FOR FURTHER INFORMATION CONTACT: Bruce Bingham, Field Supervisor, U.S.
Fish and Wildlife Service, Arcata Fish and Wildlife Office (see
ADDRESSES); by telephone at 707-822-7201; or by facsimile at 707-822-
8411. If you use a telecommunications device for the deaf (TDD), please
call the Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Acronyms and Abbreviations Used in This Document
We use many acronyms and abbreviations throughout this 12-month
finding. To assist the reader, we provide a list of these here for easy
reference:
Act = Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et
seq.)
AR = Anticoagulant Rodenticides
BLM = Bureau of Land Management
CBD = Center for Biological Diversity
CDFG = California Department of Fish and Game (see below)
CDFW = California Department of Fish and Wildlife (formerly CDFG)
CDPR = California Department of Parks and Recreation
CESA = California Endangered Species Act
CEQA = California Environmental Quality Act
CFR = Code of Federal Regulations
DPS = Distinct Population Segment
EPIC = Environmental Protection Information Center
Forest Service = U.S. Forest Service
FR = Federal Register
GIS = Geographic Information System
HCP = Habitat Conservation Plan
HMCG = Humboldt Marten Conservation Group
IPCC = Intergovernmental Panel on Climate Change
IUCN = International Union for Conservation of Nature
LANDFIRE = Landscape Fire and Resource Management Planning Tools
Project
LRMP = Land and Resource Management Plan
MDL = Multi-District Litigation
MOU = Memorandum of Understanding
MTBS = Monitoring Trends in Burn Severity
NMFS = National Marine Fisheries Service
NWFP = Northwest Forest Plan
OAR = Oregon Administrative Rules
ODF = Oregon Department of Forestry
RMP = Resource Management Plan
Service = U.S. Fish and Wildlife Service
SPR = Significant Portion of [a Species'] Range
USDA = U.S. Department of Agriculture
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 suggesting that listing a 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 (``warranted but precluded'').
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 September 28, 2010, we received a petition dated September 28,
2010, from the Center for Biological Diversity (CBD) and the
Environmental Protection Information Center (EPIC), requesting that we
consider for listing the (then-classified) subspecies Humboldt marten
(Martes americana humboldtensis), or the (now-recognized) subspecies
Humboldt marten (M. caurina humboldtensis), or the Humboldt marten DPS
of the Pacific marten (M. caurina). The petitioners further stipulated
that, based on recent genetic analyses indicating that populations of
marten from coastal Oregon (considered members of M. a. caurina) are
more closely related to M. a. humboldtensis than to M. a. caurina in
the Cascades of Oregon (citing Dawson 2008, Slauson et al. 2009a), the
range of the subspecies or DPS of the Humboldt marten should be
expanded to include coastal Oregon populations of martens. In a letter
to the petitioners dated October 22, 2010, we responded that we
reviewed the information presented in the petition and determined that
issuing an emergency regulation temporarily listing the species under
section 4(b)(7) of the Act was not warranted.
On January 12, 2012, we published in the Federal Register a 90-day
finding (77 FR 1900) that the petition presented substantial
information indicating that listing may be warranted and that initiated
a status review. For purposes of the 90-day finding, the common name
Humboldt marten referred to the then-classified American marten (M.
americana) populations in coastal northern California and coastal
Oregon.
On June 23, 2014, we published a scoping notice in the Federal
Register (79 FR 35509) that summarized the uncertainty regarding the
taxonomic classification of the subspecies (based on current genetics
information) and indicated our intent to conduct an evaluation (for the
12-month finding) of
[[Page 18743]]
a potential DPS of martens in coastal northern California and coastal
Oregon relative to the full species classification level.
According to section 3(16) of the Act, we may consider for listing
any of three categories of vertebrate animals: A species, subspecies,
or DPS (see the Service's 1996 DPS Policy at 61 FR 4722). We refer to
each of these categories as a potential ``listable entity.'' We
evaluated three possible listable entities for this 12-month finding
based upon the best available published and unpublished information for
martens in coastal northern California and coastal Oregon (for further
details, please see the Current Taxonomic Description and Listable
Entity Evaluation and Distinct Population Segment Analysis sections,
below):
Subspecies Humboldt marten (Martes americana
humboldtensis): This entity was considered not reasonable for
evaluation because its species-level name is no longer considered
valid. Specifically, Dawson and Cook (2012, entire) split the then-
classified American marten (M. americana) to recognize the Pacific
marten (M. caurina) for all martens occurring west of the Rocky
Mountain crest.
Subspecies Humboldt marten (Martes caurina humboldtensis):
This entity was considered not reasonable for evaluation because its
description is (currently) specifically linked with the extant
population that resides in coastal northern California and does not
include the coastal Oregon populations, which the best available
genetics data indicate are likely the same entity.
DPS of the Pacific marten (Martes caurina): We considered
it reasonable that a DPS of the Pacific marten constitute the listable
entity for our status review based on our evaluations of the best
scientific and commercial data currently available (including
unpublished genetics information), and our consideration of the
Service's February 7, 1996, Policy Regarding the Recognition of
Distinct Vertebrate Population Segments Under the Endangered Species
Act (DPS Policy; 61 FR 4722). As such, we considered in the scoping
notice (79 FR 35509; June 23, 2014) that the DPS include the currently
recognized M. caurina humboldtensis (i.e., Humboldt marten) and the
coastal populations of M. caurina caurina in Oregon (i.e., Oregon Coast
Range group). We solicited information regarding our consideration of
the coastal northern California and coastal Oregon populations of
Pacific marten as a single listable entity. See Listable Entity
Evaluation and Distinct Population Segment Analysis, below, for
additional discussion related to our decision that a coastal DPS of the
Pacific marten (hereafter referred to as ``coastal marten'')
constitutes the listable entity for this status review.
This notice constitutes the 12-month finding on the September 28,
2010, petition to list the (then-classified) subspecies Humboldt marten
(Martes americana humboldtensis), or the (now-recognized) subspecies
Humboldt marten (M. caurina humboldtensis), or the Humboldt marten DPS
of the Pacific marten (M. caurina) as an endangered or threatened
species.
This finding is based upon the Species Report titled ``Coastal
Oregon and Northern Coastal California populations of the Pacific
marten (Martes caurina)'' (Service, 2015) (Species Report), a
scientific analysis of available information prepared by a team of
Service biologists from the Service's Arcata Fish and Wildlife Office,
Oregon Fish and Wildlife Office, Pacific Southwest Regional Office,
Pacific Regional Office, and National Headquarters Office. The purpose
of the Species Report is to provide the best available scientific and
commercial information about the species so that we can evaluate
whether or not the species warrants protection under the Act. In it, we
compiled the best scientific and commercial data available concerning
the status of the coastal Oregon and northern coastal California
populations of Pacific marten, including past, present, and future
threats to these populations. As such, the Species Report, including
the appendix, provides the scientific basis that informs our regulatory
decision in this document, which involves the further application of
standards within the Act and its regulations and policies. The Species
Report can be found on the Internet at http://www.regulations.gov,
Docket No. FWS-R8-ES-2011-0105.
Current Taxonomic Description
The American marten (Martes americana) was originally described as
a single species by Turton (1806, entire), based on specimens from
eastern North America. In 1890, Merriam (1890, entire) considered a new
species, Mustela [=Martes] caurina, to be those martens found west of
the Rocky Mountains. In 1926, the Humboldt [Pine] marten (M. c.
humboldtensis) was described as a subspecies of Martes caurina
(Grinnell and Dixon 1926, entire); historically, this subspecies was
distributed throughout the coastal, fog-influenced coniferous forests
of northern California from northwestern Sonoma County north to the
Oregon border (Grinnell and Dixon 1926, entire). In 1953, Wright (1953,
entire) described one species, the American marten (M. americana),
which included as subspecies both the Humboldt [Pine] marten subspecies
(M. a. humboldtensis), and the former western marten species (M.
caurina), classified as M. a. caurina.
As noted above, at the time of our 90-day finding (77 FR 1900;
January 12, 2012), the Humboldt marten was classified as Martes
americana humboldtensis. Subsequently, Dawson and Cook (2012, entire)
split the American marten, recognizing the Pacific marten (M. caurina)
for all martens occurring west of the Rocky Mountain crest, based on
genetic and morphological differences. Currently, the classification of
the Humboldt marten in coastal northern California is M. c.
humboldtensis, and the marten populations occurring in adjacent coastal
Oregon are M. c. caurina. In addition, as currently recognized,
populations of martens in the Oregon Cascades northward through the
State of Washington and into British Columbia, Canada, are also M. c.
caurina.
Ongoing genetic research indicates uncertainty in the currently
accepted Pacific marten subspecies delineations in California and
Oregon. Specifically, the best available data indicate that the Martes
caurina humboldtensis population in coastal northern California
(Humboldt, Siskiyou, and Del Norte Counties) and the two known M. c.
caurina populations in coastal Oregon (Curry, Coos, coastal portion of
Douglas, coastal portion of Lane, Lincoln, and Tillamook Counties) are
likely a single evolutionary unit (clade) (Slauson et al. 2009a, p.
1,340; Schwartz and Slauson 2015, pers. comm.) (as noted in the scoping
notice that published in the Federal Register on June 23, 2014 (79 FR
35509), and was made available for review at http://www.regulations.gov, Docket No. FWS-R8-ES-2014-0023). Although
questions regarding the taxonomy of marten subspecies in northern
California and Oregon are not new (i.e., both the petition we received
(CBD and EPIC 2010) and our 90-day finding (January 12, 2012; 77 FR
1900) identified ongoing genetic research and taxonomic uncertainty),
the best available information indicate that the original designation
of two separate marten subspecies occurring in coastal northern
California and coastal Oregon is likely invalid (Schwartz and Slauson
2015, pers. comm.).
[[Page 18744]]
Listable Entity Evaluation and Distinct Population Segment Analysis
Based on the September 28, 2010, petition, and information received
both prior and subsequent to our June 23, 2014, scoping notice
regarding the listable entity, we considered whether the potential
coastal DPS of Pacific marten meets the definition of a DPS as
described in the Service's DPS Policy (61 FR 4722; February 7, 1996).
Section 3(16) of the Act defines the term ``species'' to include
``. . . 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 have always understood the phrase
``interbreeds when mature'' to mean that a DPS must consist of members
of the same species or subspecies in the wild that would be
biologically capable of interbreeding if given the opportunity, but all
members need not actually interbreed with each other. A DPS is a subset
of a species or subspecies, and cannot consist of members of a
different species or subspecies. The ``biological species concept''
defines species according to a group of organisms, their actual or
potential ability to interbreed, and their relative reproductive
isolation from other organisms. This concept is a widely accepted
approach to defining species. The Act's use of the phrase ``interbreeds
when mature'' reflects this understanding. Use of this phrase with
respect to a DPS is simply intended to mean that a DPS must be
comprised of members of the same species or subspecies. As long as this
requirement is met, a DPS may include multiple populations of
vertebrate organisms even if they may not actually interbreed with each
other. For example, a DPS may consist of multiple populations of a fish
species separated into different drainages. While these populations may
not actually interbreed with each other, their members are biologically
capable of interbreeding.
The National Marine Fisheries Service (NMFS) and the Service
published a joint Policy Regarding the Recognition of Distinct
Vertebrate Population Segments Under the Endangered Species Act (DPS
Policy on February 7, 1996 (61 FR 4722). According to the DPS Policy,
two elements must be satisfied in order for a population segment to
qualify as a possible DPS: discreteness and significance. If the
population segment qualifies as a DPS, the conservation status of that
DPS is then evaluated to determine whether it is endangered or
threatened.
A population segment of a vertebrate species may be considered
discrete if it satisfies either one of the following conditions: (1) It
is markedly separated from other populations of the same taxon as a
consequence of physical, physiological, ecological, or behavioral
factors; or (2) it is delimited by international governmental
boundaries within which differences in control of exploitation,
management of habitat, conservation status, or regulatory mechanisms
exist that are significant in light of section 4(a)(1)(D) of the Act.
If a population is found to be discrete, then it is evaluated for
significance under the DPS Policy on the basis of its importance to the
taxon to which it belongs. This consideration may include, but is not
limited to, the following: (1) Persistence of the discrete population
segment in an ecological setting unusual or unique to the taxon; (2)
evidence that loss of the discrete population segment would result in a
significant gap in the range of a taxon; (3) evidence that the
population represents the only surviving natural occurrence of a taxon
that may be more abundant elsewhere as an introduced population outside
of its historical range; or (4) evidence that the population differs
markedly from other populations of the species in its genetic
characteristics.
If a population segment is both discrete and significant (i.e., it
qualifies as a potential DPS), its evaluation for endangered or
threatened status is based on the Act's definitions of those terms and
a review of the factors listed in section 4(a) of the Act. According to
our DPS Policy, it may be appropriate to assign different listing
classifications to different DPSs of the same vertebrate taxon.
We were petitioned to list collectively two groups of the Pacific
marten (two populations in Oregon and one in California) that are
currently recognized as belonging to two separate subspecies (as
described above). To ensure that we evaluated the most accurate
listable entity based on the best scientific and commercial data
currently available (including unpublished genetics information), we
published a scoping notice in the Federal Register on June 23, 2014 (79
FR 35509), notifying the public that we considered it reasonable that a
coastal DPS of the Pacific marten constitute the listable entity for
our status review.
We received eight comment letters from six entities in response to
our June 23, 2014, scoping notice. Four entities agreed with our
proposed DPS, one was silent, and one disagreed with our evaluation of
a coastal DPS of the Pacific marten as the listable entity; two
entities commented twice reiterating their same positions. The
commenter who disagreed with the proposed coastal DPS of the Pacific
marten as the listable entity believed more information, including
genetics, would be required and that the entity we proposed would not
be a valid DPS according to Service criteria. Following publication of
the scoping notice in the Federal Register, we received more genetics
information (Schwartz and Slauson 2015, pers. comm.) that supports our
consideration of a coastal DPS of the Pacific marten.
After taking into consideration the comments received and
conducting further evaluation of the best available scientific and
commercial information (including additional genetics information), we
confirm here that this DPS is a listable entity, including the
currently recognized Martes caurina humboldtensis (i.e., Humboldt
marten) and the coastal populations of M. caurina caurina in Oregon
(i.e., Oregon Coast Range group). This entity is reasonable given:
(1) The best available data (e.g., new genetics information,
similar habitat usage) suggest that the coastal northern California
marten population and the coastal Oregon marten populations represent a
single evolutionary entity as opposed to two separate entities
(Schwartz et al., In prep.). In particular, Schwartz et al. (In prep.)
has provided substantive information (with both mitochondrial and
nuclear DNA evaluations) that the marten populations occurring in
coastal northern California and coastal Oregon are unique and more
closely related to each other than to other groups/populations of
Pacific martens, to the extent that they are diagnosably distinct from
all other Pacific martens.
(2) Existing genetics information (Slauson et al. 2009a, entire)
suggests that subspecies-level taxonomy of M. c. humboldtensis, M. c.
caurina, and possibly other subspecies of the Pacific marten as
currently classified may be inaccurate.
(3) The DPS Policy (February 7, 1996; 61 FR 4722) states that the
population segment under consideration must be evaluated for
discreteness and significance in relation to the remainder of the taxon
to which it belongs. Ordinarily, in the present case we would evaluate
the marten populations relative to the subspecies to which they belong,
but the populations in question currently represent two separate
subspecies and there is uncertainty as to the legitimacy of those
subspecies classifications, rendering such an evaluation invalid.
[[Page 18745]]
(4) Uncertainty in the subspecies-level taxonomy of Pacific marten
logically necessitates that we elevate our evaluation of the DPS
relative to the Pacific marten at the full species level. In other
words, we apply the criteria for evaluating a coastal DPS of the
Pacific marten relative to the full species Pacific marten (Martes
caurina) as a whole.
(5) The DPS Policy (February 7, 1996; 61 FR 4722) states that ``In
all cases, the organisms in a population are members of a single
species or lesser taxon.'' Therefore, given (1) through (4) above, an
evaluation at the species level is appropriate. Consequently, for
purposes of this Finding, below we evaluate the Pacific marten
populations that occur in coastal Oregon and coastal northern
California under our DPS Policy.
For this 12-month finding and DPS analysis of the Pacific marten
populations that occur in coastal Oregon and coastal northern
California, we reviewed and evaluated all available published and
unpublished information, including numerous publications, reports, and
other data submitted by the public. Marten distribution in coastal
northern California and coastal Oregon is discussed in detail in the
``Species Distribution'' section of the Species Report titled ``Coastal
Oregon and Northern Coastal California populations of the Pacific
marten (Martes caurina)'' (Service 2015, pp. 28-32), which is available
on the Internet at http://www.regulations.gov, Docket No. FWS-R8-ES-
2011-0105.
Discreteness
Under the DPS Policy, a population segment of a vertebrate taxon
may be considered discrete if it satisfies either one of the following
conditions:
(1) It is markedly separated from other populations of the same
taxon as a consequence of physical, physiological, ecological, or
behavioral factors. Quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation.
(2) It is delimited by international governmental boundaries within
which differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act. As the marten
populations in question here do not transcend an international
boundary, this criterion does not apply.
As described below, the Pacific marten populations that occur in
coastal Oregon and coastal northern California are markedly separated
from other Pacific marten populations by geographical isolation (i.e.,
separated by areas of unsuitable habitat), and marked genetic
differences between those coastal populations (coastal Oregon and
coastal northern California) and other populations of Pacific marten
are evidence of this long-standing separation. The extant population in
coastal northern California is separated from the Sierra marten
subspecies (Martes caurina sierrae) by unsuitable habitat to the east
in the Klamath River canyon. The coastal central Oregon extant
population is separated from Pacific marten populations to the east (in
the Oregon Cascade Mountains) primarily by unsuitable habitat within
the Willamette Valley. Although some suitable habitat occurs between
the coastal southern Oregon extant population area and the southern
Cascades population of Pacific martens to the east, the distance to
large blocks of suitable habitat in the southern Cascade Mountains far
exceeds the mean maximum dispersal distance for martens (see discussion
below). Additionally, martens that occur in coastal Oregon and coastal
northern California occur in areas without significant, persistent
snowpack (Slauson 2003, p. 66; Slauson et al., In prep.). Mountain
ranges to the east that have both unsuitable marten habitat and are
covered by significant, persistent snowpack stand between the coastal
Oregon and coastal northern California populations of Pacific martens
and other Pacific marten populations (e.g., separation of Humboldt and
Sierra Nevada populations), thereby effectively isolating the coastal
marten populations from other Pacific martens. East-west movements that
would potentially connect Pacific marten populations in coastal Oregon
and coastal northern California with inland Pacific marten populations
are likely rare because:
(1) Most juvenile marten dispersal distances (that are published in
literature) in both logged and unlogged forests range from less than or
equal to 5 km (3.1 mi) (Broquet et al. 2006, p. 1,694) to approximately
15 km (9.3 mi) (Phillips 1994, pp. 93-94; Pauli et al. 2012, p. 393).
The distance between the coastal Oregon and coastal northern California
populations of Pacific martens and other Pacific marten populations to
the east exceeds the likely maximum dispersal distance.
(2) Pacific martens within the three extant populations in coastal
Oregon and coastal northern California likely only need to disperse
short distances to establish a home range because there are typically
sufficient amounts of unoccupied suitable habitat available within
their natal area.
(3) Large patches of unsuitable habitat on the eastern edge of the
historical range in this region would likely deter juvenile martens
from moving east. As described below in the section Summary of Species
Information, the coastal Oregon and coastal northern California
populations of Pacific martens require a dense shrub understory
comprised of shade-tolerant shrub species within the conifer-dominated
overstory that they occupy (Zielinski et al. 2001, p. 485; Slauson et
al. 2007, p. 464), and in coastal Oregon and coastal northern
California, this dense shrub layer generally does not occur outside of
the coastal fog-influenced areas. Thus, martens in coastal northern
California and coastal Oregon are functionally isolated from other
marten populations by their dependence on the dense shrub layer found
in the coastal coniferous forests of this region.
The coastal Oregon and coastal northern California populations of
Pacific martens are also markedly separated from other populations of
the Pacific marten as evidenced by quantitative measures of genetic
discontinuity. The Humboldt marten was historically distributed
throughout the coastal coniferous forests of northern California from
northwestern Sonoma County northward to the Oregon border (Grinnell et
al. 1937, pp. 207-210). Recent phylogenetic analyses using
mitochondrial DNA (mtDNA) support the distinctiveness of the Humboldt
marten subspecies, based on the presence of distinct haplotypes shared
by historical museum specimens and martens currently occupying portions
of the historical range in northern coastal California (Slauson et al.
2009a, entire). Marten populations in coastal Oregon, which were
historically described as M. c. caurina, also share these haplotypes,
leading Slauson et al. (2009a, pp. 1338-1339) to suggest that martens
in the Coast Range of Oregon may also be M. c. humboldtensis.
Furthermore, preliminary results of a subspecific genetic evaluation of
the Pacific marten by Schwartz et al. (In prep.)--using nuclear DNA
(nDNA) and samples from substantially more martens than used by Slauson
et al. (2009a)--demonstrate that the coastal Oregon and coastal
northern California populations of Pacific martens are clearly
distinguishable from other populations of Pacific marten on the basis
of their genetic characteristics. Schwartz et al. (In prep.) indicate
that coastal Oregon and northern coastal California marten populations
represent a single evolutionary clade, calling into
[[Page 18746]]
question the separation of the original subspecies range boundaries
(i.e., M. c. humboldtensis in northern coastal California and M. c.
caurina in coastal Oregon) at the California-Oregon border. Although
some low degree of introgression indicates occasional past movement of
individuals between coastal and inland populations, the evidence
suggests this was an infrequent occurrence (Schwartz et al., In prep.);
thus, the coastal Oregon and coastal northern California populations of
Pacific martens are effectively genetically discrete from other
populations of Pacific marten.
In summary, the best available information indicates that Pacific
marten populations in coastal Oregon and coastal northern California
are geographically isolated and genetically discrete from all other
populations of the Pacific marten. Therefore, the marked separation
condition for discreteness under our DPS Policy is met.
Significance
If a population segment is considered discrete under one or more of
the conditions described in the Service's DPS Policy, its biological
and ecological significance will be considered in light of
Congressional guidance that the authority to list DPSs be used
``sparingly'' (see Senate Report 151, 96th Congress, 1st Session) while
encouraging the conservation of genetic diversity. In making this
determination, we consider available scientific evidence of the DPS's
importance to the taxon to which it belongs.
Because precise circumstances are likely to vary considerably from
case to case, the DPS Policy does not describe all the classes of
information that might be used in determining the biological and
ecological importance of a discrete population. However, the DPS Policy
describes four possible classes of information that provide evidence of
a population segment's biological and ecological importance
(significance) to the taxon to which it belongs. This consideration of
the population segment's significance may include, but is not limited
to, the following:
(1) Persistence of the discrete population segment in an ecological
setting unusual or unique to the taxon;
(2) Evidence that loss of the discrete population segment would
result in a significant gap in the range of a taxon;
(3) Evidence that the discrete population segment represents the
only surviving natural occurrence of a taxon that may be more abundant
elsewhere as an introduced population outside its historical range; or
(4) Evidence that the discrete population segment differs markedly
from other populations of the species in its genetic characteristics.
To be considered significant, a population segment needs to satisfy
only one of these conditions. Other classes of information that might
bear on the biological and ecological importance of a discrete
population segment may also be used as appropriate, to provide evidence
for significance, as described in the DPS Policy (61 FR 4722; February
7, 1996). At least two of the significance criteria are met for the
marten populations in coastal Oregon and coastal northern California.
First, we find that populations of Pacific martens in coastal Oregon
and coastal northern California differ markedly from other populations
of the Pacific marten species in their genetic characteristics. As
described above under ``Discreteness,'' the coastal Oregon and coastal
northern California populations of Pacific martens are genetically
distinct from all other populations of Pacific martens (Schwartz et
al., In prep.). As a result, loss of the marten populations from
coastal Oregon and coastal northern California would result in a
reduction in Pacific marten genetic diversity. Second, we find that the
loss of martens from coastal Oregon and coastal northern California
would result in a significant gap in the range for the Pacific marten.
The coastal populations of martens in California and Oregon represent
the only coastal populations of Pacific martens in these States and
inhabit a habitat association unique from other non-coastal marten
populations--that is, areas consisting of occasional, non-persistent
snowpack (below 914 meters (m) (3,000 feet (ft)) with a mesic, shade-
tolerant shrub layer (understory) within coastal coniferous forest
habitat (see ``Life History'' section of the Species Report). The
requirement of this dense (greater than 70 percent cover), shrubby
understory is particularly unusual for martens, and is a unique habitat
association not described elsewhere in the distribution of either
Pacific martens or American martens in North America (Slauson et al.,
In prep.(a)). The coastal Oregon and coastal northern California
populations of Pacific martens are also the only martens known to
utilize coastal serpentine habitat and dune forest habitat distributed
on coastal terraces. These genetic differences and the evidence that a
significant gap in the range of the taxon would result from the loss of
the discrete population segment both individually satisfy the
significance criterion of the DPS Policy. Therefore, under the
Service's DPS Policy, we find that the populations of Pacific martens
in coastal Oregon and coastal northern California are significant to
the taxon to which they belong.
Conclusion of DPS Analysis Regarding Pacific Martens in Coastal Oregon
and Coastal Northern California
As stated above under Current Taxonomic Description, the best
available scientific and commercial information suggests that the
coastal Oregon populations of Pacific marten (Martes caurina caurina)
are likely the same entity as the currently classified Humboldt marten
(M. c. humboldtensis). We find that the coastal Oregon and coastal
northern California populations of Pacific martens collectively
constitute a valid DPS under the Service's DPS Policy because this
population segment is both discrete and significant to the taxon to
which it belongs. We therefore consider the coastal Oregon and coastal
northern California populations of Pacific martens collectively as the
``coastal DPS of the Pacific marten,'' which constitutes the listable
entity for this status review. Throughout this document when we use the
term ``coastal marten,'' we are using this term as shorthand for the
coastal DPS of the Pacific marten.
Summary of Species Information
A thorough review of the taxonomy, life history, biophysical
environment, habitat use, distributions, and population abundance/
trends of the coastal DPS of Pacific marten is presented in the Species
Report (Service 2015, pp. 1-40) available on the Internet at http://www.regulations.gov, Docket No. FWS-R8-ES-2011-0105). A summary of this
information is presented below. We used data specific to coastal marten
populations when they were available; when such information was
lacking, we relied on information regarding North American martens in
general (American or Pacific martens), and have made these distinctions
in the text that follows.
Life History
Two species of marten, divided into 14 total subspecies, inhabit
North America. Collectively, North American martens are characterized
by the long and narrow body type typical of the mustelid family
(Mustelidae; e.g., weasels, minks, otters and fishers), overall brown
pelage (fur) with distinctive coloration on the throat and upper chest
that varies from orange to yellow to cream, large and distinctly
[[Page 18747]]
triangular ears, and a bushy tail that is proportionally equivalent to
about 75 percent of the body length (Clark et al. 1987, p. 2; Powell et
al. 2003, p. 636).
Marten activity patterns coincide with their prey species
availability. Specifically, martens are active year-round and
seasonally adjust their activity patterns to synchronize with those of
their key prey species (Zielinski et al. 1983, pp. 387-388). Overall,
the diet of North American marten species is dominated by mammals, but
birds, insects, and fruits are seasonally important (Martin 1994, pp.
298-301). Diet analysis for the coastal marten is currently limited to
scats collected from the coastal northern California population during
summer and fall, and includes mammals, berries, birds, and reptiles
(Slauson and Zielinski, In prep.). Sciurid (members of the squirrel
family) and cricetid rodents (i.e., New World rats and mice) dominate
the coastal marten's diet, with the most frequent prey species being
chipmunks (Tamias spp.) and red-backed voles (Myodes californicus),
and, to a lesser extent, Douglas squirrels (Tamiasciurus douglasii) and
flying squirrels (Glaucomys sabrinus) (Slauson and Zielinski, In
prep.).
Information on coastal marten reproduction and survivorship is
lacking; therefore our analysis is based on knowledge of North American
martens in general, which are polygamous mammals. Female martens mate
no sooner than 15 months of age and first litters are produced no
sooner than 24 months of age (Strickland et al. 1982, p. 601). Mating
occurs from late June to early August (Markley and Bassett 1942, pp.
606-607), and females give birth in March and April (Strickland et al.
1982, p. 602). Female martens are capable of producing from one to five
kits per litter, but the modal average is two to three (Strickland and
Douglas 1987, p. 602; Mead 1994, p. 410). Information is not available
on the average number of young raised to weaning, the average number of
young recruited into the population per female, or the effects of
annual variation in environmental conditions and prey populations on
kit survival. Regarding longevity, captive Pacific martens are known to
reach 15 years of age (Clark et al. 1987, p. 3); however, data from
American marten individuals in the wild in the Algonquin Region of
Ontario, Canada, indicate that 10 percent (of 2,076 females trapped)
were more than 5 years old (Strickland and Douglas 1987, p. 535).
Finally, age structure of coastal martens has not been studied,
although the best available information from an untrapped population of
Pacific martens in the Sierra Nevada mountains indicates relatively
consistent proportions of yearling and adult age classes (Slauson et
al., In prep.(a)).
Juvenile dispersal of the American marten is generally thought to
occur as early as August, although fall, winter, and spring (the year
after birth) dispersal periods have been reported (Clark and Campbell
1976, p. 294; Slough 1989, p. 993). Juvenile dispersal in coastal
northern California and Sierra Nevada martens has been observed to
occur as early as August and continues at least until the following
summer season (Slauson and Zielinski 2014, unpubl. data). Information
is not available regarding the timing of juvenile dispersal for coastal
martens in Oregon. Pauli et al. (2012, p. 393) found that Pacific and
American martens exhibit similar dispersal distances, averaging 15.5 km
(9 mi). Most studies find that the majority of juvenile martens
disperse relatively short distances to establish home ranges, ranging
from less than or equal to 5 km (3.1 mi) (Broquet et al. 2006, p.
1,694) to approximately 15 km (9.3 mi) (Phillips 1994, pp. 9394; Pauli
et al. 2012, p. 393). However, Broquet et al. (2006, p. 1695) also
describe juvenile martens as capable of covering long distances during
dispersal, up to 82 km (50 mi) in their study. Other researchers have
reported instances of dispersal movements by martens ranging from 40 to
80 km (25 to 50 mi) (Thompson and Colgan 1987, pp. 831-832; Fecske and
Jenks 2002, p. 310), up to 149 km (93 mi) or even 160 km (100 mi) in
distance (Slough 1989, p. 993; Kyle and Strobeck 2003, p. 61). Based on
minimal genetic structuring of marten populations in a heavily
harvested forest landscape, Kyle and Strobeck (2003, pp. 60-61)
suggested that habitat fragmentation may not necessarily impede marten
movement to the degree formerly understood. However, Kyle and Strobeck
(2003, p. 65) also caution that smaller scale disturbances may still
act as partial barriers to marten gene flow. Johnson (2008, pp. 33-36)
found that juvenile martens traveled slower, shorter distances, and
suffered twice the mortality risk in logged versus unlogged landscapes.
Therefore, the best available information suggest that landscape
condition (e.g., the spatial distribution of unlogged and logged
stands) has important effects on dispersal dynamics, affecting both the
distance dispersers can travel and the success rate they have in
establishing home ranges and surviving to adulthood.
Intraguild predation and interspecific competition occurs naturally
within the range of the coastal DPS of Pacific marten. Intraguild
predation refers to killing and eating of potential competitors that
utilize the same prey resources. Interspecific competition is a form of
competition in which individuals of a different species compete for the
same resource in an ecosystem (as opposed to intraspecific competition
that involves organisms of the same species). Martens are susceptible
to predation by larger mammalian and avian predators, typically
habitat-generalist species, including coyote (Canis latrans), red fox
(Vulpes vulpes), bobcat (Felis rufus), fishers (Pekania pennanti), and
great horned owl (Bubo virginianus) (Thompson 1994, p. 276; Lindstrom
et al. 1995, entire; Bull and Heater 2001, p. 4; McCann et al. 2010, p.
11). Marten predators may vary depending on the quality of the habitat.
For example, American marten populations in highly altered forest
landscapes show higher rates of predation by habitat generalist
carnivores (and lower annual survival rates) than those in less-altered
forest landscapes (Thompson 1994, p. 278)). Because marten populations
are strongly influenced by adult and juvenile survivorship (Buskirk et
al. 2012, p. 89), predation of martens can have a meaningful effect on
abundance and population growth rates. Additional discussion on
predation as a stressor on the coastal marten is provided below in
Summary of Information Pertaining to the Five Factors.
Habitat Description
The preferred habitat type for the coastal DPS of Pacific marten
occurs in some of the most productive forests in the world. In
unmanaged, late-seral stages, these forests are typically composed of
long-lived, large trees, with multi-layered canopy structure,
substantial large woody debris (standing and downed), and abundant
ferns, herbs, and shrubs on the forest floor (Sawyer et al. 2000,
entire; Chappell et al. 2001, entire; Sawyer 2007, entire; DellaSala et
al. 2011, entire). The forests are largely coniferous and typically
dominated by coast Douglas-fir (Pseudotsuga menziesii menziesii),
western hemlock (Tsuga heterophylla), and Sitka spruce (Picea
sitchensis) in Oregon, and redwood (Sequoia sempervirens) and coast
Douglas-fir in California (Ricketts et al. 1999, entire; Sawyer 2007,
entire). Higher elevation areas also include sub-dominant conifers such
as western red cedar (Thuja plicata), Port Orford-cedar (Chamaecyparis
lawsoniana), grand fir (Abies grandis), sugar pine (Pinus lambertiana),
and white fir (Abies
[[Page 18748]]
concolor) (Chappell et al. 2001, entire; Sawyer 2007, entire).
Hardwood-dominated stands are uncommon, although hardwood species such
as tanoak (Notholithocarpus densiflorus), golden chinquapin
(Chrysolepis chrysophylla), and Pacific madrone (Arbutus menziesii) are
common canopy subdominants. Red alder (Alnus rubra) can occur as an
early successional overstory dominant in the uplands in some near-coast
locations or post-logging sites. Riparian forests are dominated by
broadleaf species such as red alder, black cottonwood (Populus
trichocarpa), bigleaf maple (Acer macrophyllum), and mesic shrub
species such as vine maple (A. circinatum).
A dense understory of shrubs and herbaceous plants are a key
habitat requirement for the coastal marten (see ``Habitat Use'' section
of the Species Report (Service 2015, pp. 18-27)). Species presence and
dominance is shaped largely by the combination of soil nutrients and
moisture, with herbaceous species such as sword fern (Polystichum
munitum) dominating on nitrogen rich or very moist sites, and evergreen
shrubs such as Pacific rhododendron (Rhododendron macrophyllum) and
salal or wintergreen (Gaultheria sp.) dominating on nutrient poor or
drier sites (Chappell and Kagan 2001, entire). Other dominant or co-
dominant understory shrub species include evergreen huckleberry
(Vaccinium ovatum), salmonberry (Rubus spectabilis), red huckleberry
(Vaccinium parvifolium), and in serpentine habitats (see description
below) dwarf tanbark (Notholithocarpus densiflorus var. echinoides) and
huckleberry oak (Quercus vaccinifolia) (Jimerson et al. 1996, pp. A13-
A15; Sawyer et al. 2000, entire; Chappell et al. 2001, entire). Many of
the dominant shrub species are adapted to fire by having lignotubers,
which are basal swellings at the interface between the roots and shoots
usually just below the soil surface, allowing these species to quickly
sprout after fire kills the shoots and thus maintain site dominance
(Agee 1993, p. 133).
Two additional, rare forest habitats are of particular relevance to
coastal martens: Coastal serpentine and coastal dune forest. Forests in
serpentine habitats are typically open and rocky with stunted trees
that contrast sharply with the dense, rapidly-growing stands on more
productive, non-serpentine soils that surround these sites (Jimerson et
al. 1995, pp. A8-A31). Martens are not known to occupy these more open,
drier, interior areas. However, on the extreme coastal edge of the
serpentine habitats that occur in coastal northern California and
coastal Oregon, increased moisture and summer fog supports dense,
spatially-extensive shrub layers; coastal martens have been found in
this wetter variant of coastal serpentine habitat in both Oregon and
California. The serpentine communities used by coastal martens are
composed of a variety of coniferous trees, such as Douglas-fir, sugar
pine, lodgepole pine (Pinus contorta), western white pine (P.
monticola), Jeffrey pine (P. jeffreyi), knobcone pine (P. attenuatta),
and Port Orford-cedar, and are dominated by mast-producing shrubs such
as dwarf tanbark, huckleberry oak, and red huckleberry (Jimerson et al.
1995, p. C1; Slauson 2003, pp. 5, 9, 13). The coastal dune forest
communities where coastal martens have been found are predominantly in
coastal Oregon and are typically dominated by shore pine (P. contorta
contorta), the coastal form of lodgepole pine, and in some areas co-
dominated by Sitka spruce occurring in stabilized dunes on marine
terraces. Although martens have been found in these less-common habitat
types, it is important to note that the more extensive dominant forest
types (i.e., coastal coniferous forests) support the majority of the
historical marten distribution in coastal Oregon and coastal northern
California.
Coastal martens select habitat at four primary spatial scales:
Micro-scale (resting and denning structures), stand-scale, home range,
and landscape-scale (facilitating movement, occupancy, and population
dynamics).
(1) Micro-scale--Rest structures are used daily by martens between
foraging bouts to provide thermoregulatory benefits and protection from
predators (Taylor and Buskirk 1994, pp. 253-255). Reuse rates for
individual rest structures are low and selection for structure type
changes seasonally to meet thermoregulatory needs (e.g., Spencer 1987),
such that multiple resting structures meeting seasonal requirements are
required across the home range. Large-diameter live trees, snags, and
logs provide the main types of resting structures for martens (Spencer
et al. 1983, pp. 1182-1185; Schumacher 1999, pp. 26-58; Slauson and
Zielinski 2009, pp. 41-42). Denning structures used by female martens
to give birth to kits are called natal dens, and the subsequent
locations where they move their kits are referred to as maternal dens.
Ruggiero et al. (1998, pp. 665-669) found that both the characteristics
of the den structures and the characteristics of the stands in which
they were found influenced den-site selection. This is likely due to
the importance of high-quality foraging habitat in close proximity to
den sites, allowing females to simultaneously maximize the energy they
gain from foraging during lactation and minimize the time spent away
from kits, especially when they are dependent on their mothers for
thermoregulation. The most common den structures used by Pacific and
American martens are large-diameter, live and dead trees with cavities
(Thompson et al. 2012, p. 223).
(2) Stand-scale--Martens select forest stands that provide habitat
structure supporting one or more life history needs that include
foraging, resting, or denning. Coastal martens in California most
strongly selected stands of old-growth, conifer-dominated forests with
dense shrub layers (Slauson et al. 2007, pp. 464-465). Other than the
late-mature developmental stage, which was used in proportion to its
availability, stands in earlier developmental stages were selected
against (Slauson et al. 2007, pp. 462-464). These old-growth and late-
mature stands most often were dominated by Douglas-fir overstory, but
also had mature hardwood understories composed of either tanoak or
golden chinquapin. Shrub layers were dense (greater than 70 percent
cover), spatially extensive, and dominated by evergreen huckleberry,
salal, and rhododendron (Slauson et al. 2007, p. 465). The majority of
detections of martens in coastal southern Oregon share these same stand
characteristics (Zielinski et al. 2001, p. 485).
(3) Home Range--Pacific and American martens exhibit strong habitat
selection at the home range scale, suggesting that this scale of
selection most directly influences an individual's fitness (Thompson et
al. 2012, p. 210). Martens establish home ranges to encompass their
year-round resource needs and, during the breeding season, gain access
to members of the opposite sex. Marten home ranges are often positioned
to maximize high-quality habitat (typically greater than 70 percent
high-quality, late-successional forest (reviewed in Thompson et al.
2012, p. 218)) and to minimize low-quality habitat (e.g., recent clear
cuts, partial harvest) (Phillips 1994, pp. 59-60). Females, due to
their solitary role raising young, have unique needs that require
access to suitable den sites located near reliable and nearby prey
resources to support the energetic demands of lactation and providing
food for kits. In coastal northern California, Slauson and Zielinski
(2014, unpubl. data) found 97 percent (38 of 39) of the female within-
home-range resting and active locations occurred in the core old-growth
and late-mature
[[Page 18749]]
riparian habitat patches. In comparison, 77 percent (30 of 39) of the
male within-home-range resting and active locations occurred in the
core old-growth and late-mature riparian habitat patches (Slauson and
Zielinski 2014, unpubl. data). Also of note is that there is an inverse
relationship between the amount of high-quality habitat and marten home
range size (i.e., as the amount of high-quality habitat decreases, home
range size increases) (Thompson 1994, p. 276; Potvin and Breton 1997,
p. 462; Fuller and Harrison 2005, pp. 715-719).
(4) Landscape-scale--The pattern and composition of habitat at this
scale affects: (a) The ability of martens to successfully disperse and
find suitable home ranges; (b) survival and species occurrence over
time and space; and (c) ultimately, population size and persistence.
Successful dispersal requires the existence of functional habitat
connectivity between patches of habitat suitable for reproduction to
maintain or expand population size and distribution. Also, during
dispersal, martens use a search strategy that is not random or linear,
suggesting they are responding to habitat cues and that landscape
pattern likely influences movement trajectories (Johnson 2008, pp. 27-
29, 36-39). Compared to other species closely associated with late-
successional forest, American and Pacific marten populations, including
the coastal marten, are sensitive to the loss or fragmentation of high-
quality habitat at the landscape scale. For example, martens exhibit a
progression of responses to timber harvest as the proportion of habitat
affected by intensive logging activities increases. Such activities
include, but are not limited to, clear cutting (see review in Thompson
et al. 2012), partial harvest (Potvin et al. 2000, pp. 851-854; Fuller
and Harrison 2005, pp. 715-716; Godbout and Ouellet 2008, pp. 336-338),
and shelterwood cutting (Ellis 1998, p. 41-49). As a result, the
combination of habitat loss and fragmentation of remnant suitable
habitat effectively lowers the density of martens by reducing the
number of home ranges that can be supported (Thompson 1994, p. 276).
Historical and Current Distribution of Coastal Martens and Suitable
Habitat
At the time of European settlement, the coastal marten occurred in
all coastal Oregon counties and the coastal northern counties of
California within late-successional coniferous forests. The majority of
historical (pre-1980) verifiable marten detections (i.e., occurrence
records supported by direct physical evidence such as tracks,
photographs, and carcasses) were within the fog-influenced coastal
coniferous forest as opposed to interior forests (Grinnell and Dixon
1926, p. 413). Specifically, Slauson and Zielinski (2007, p. 241)
reported 83 percent of the coastal northern California marten
historical records occurring less than 25 km (15 mi) from the coast and
no records occurring greater than 35 km (22 mi) from the coast, while
our analysis (see Service 2015, pp. 6, 31) revealed greater than 90
percent of the coastal Oregon marten historical records occurring
closer to the coast than to the interior portions of the coastal
marten's range. Historical abundance of coastal martens is unknown.
However, as is typical of mammalian carnivores, coastal martens likely
never occurred in high densities.
Unregulated fur trapping occurred throughout the coastal marten's
historical range, and by the late 1920s, few marten were captured where
they were once considered relatively abundant (Zielinski and Golightly
1996, entire). A marked decline in the number of coastal marten
harvested in coastal northern California led to the closure of marten
trapping in northwestern California in 1946. In Oregon, marten fur
trapping remains legal Statewide. Historical fur trapping is thought to
have resulted in a significant contraction of coastal marten
distribution and the extirpation of coastal marten from large portions
of its historical range. Although we can make conclusions about the
general historical distribution of coastal martens, information on
historical population size is not available, thus precluding an
accurate assessment of the impact of unregulated trapping on coastal
marten population abundance.
Due to the lack of surveys for coastal martens, little information
is available regarding their current distribution; this is particularly
true for coastal Oregon. We do know, however, that there are at least
three extant populations of coastal martens, one in coastal northern
California, one in coastal southern Oregon, and one in coastal central
Oregon, as described in detail below, and we have information regarding
the extent of suitable habitat that is currently available to coastal
martens throughout their range. It is therefore possible that coastal
martens may occur in any of these areas of suitable habitat that have
not been surveyed, or have been surveyed only sporadically. Here we
briefly describe the areas of suitable habitat available to coastal
martens.
Slauson et al. (In prep.(b)) developed a landscape habitat
suitability model that we used to assess how much suitable habitat is
currently available to coastal martens. The model was developed by
identifying the combination of environmental, topographic, disturbance
history, and vegetation variables that best described the distribution
of marten detection/non-detection survey data. Specifics regarding
model development and variables can be found in the ``Current Landscape
Habitat Suitability'' section of the Species Report (Service 2015, pp.
26-27). The model categorizes the landscape into low, medium, and high
suitability classes representing the relative probability of marten
occupancy of habitat at the landscape scale.
Model results indicate that approximately 41 percent of the coastal
marten's historical range contain suitable habitat (described as low,
medium, and high suitability habitat) for coastal martens (see
``Current Landscape Habitat Suitability'' section of the Species
Report). The model identified approximately 59 percent of the remaining
lands within the historical range of the coastal marten to be
unsuitable, which includes (but is not limited to) forested habitat
that is not utilized by martens (e.g., heavily managed timber lands),
urban and suburban developments, and agricultural lands. However, it is
important to note that, for the purposes of this analysis, we
considered ``low suitability habitat'' as defined in this model to be
``unsuitable'' when examining the current and long-term stressors to
the coastal marten and its habitat into the future. In other words, in
evaluating stressors to the coastal marten and its habitat, we
considered only areas that provide moderate- to high-suitability
habitat as identified by the model. We came to this conclusion based on
feedback from the species experts (Slauson et al., In prep.(a)) who
indicate that these ``low suitability habitat'' areas currently have a
low probability of coastal marten occurrence. Including these areas as
suitable habitat for the purposes of this analysis would bias the
amount of actual suitable habitat present both currently and in the
future.
Much of the coastal marten's historical habitat has been lost.
Extensive logging of old-growth redwood habitat in coastal northern
California began in the late 1800s, and coincided with unregulated fur
trapping. Late-successional coniferous forests in coastal Oregon were
also extensively harvested in the early 1900s. Currently, less than 5
percent of the redwood forests existing at the time of European
settlement remain within the
[[Page 18750]]
historical range of the coastal marten in coastal northern California
(Save the Redwoods League 2015, no page number). Based on the best
available information, much of the coastal coniferous forest habitat in
both States, especially within a few miles of the coast, appears to be
currently owned (in general) by either private industrial timber
companies or smaller land owners, and managed for timber production.
Within the coastal marten's historical range, the majority of
remaining late-successional coniferous forests suitable for the coastal
marten is within national forests, and national and State parks. Where
martens are known to occur, relatively high amounts of moderate- to
high-suitability habitat are still found, and much of this habitat
occurs in areas that are managed for the maintenance or enhancement of
late-successional forest conditions that are beneficial to coastal
martens. For example, approximately 71, 79, and 90 percent of the total
available suitable habitat on Federal lands in the coastal central
Oregon, coastal southern Oregon, and coastal northern California
population areas, respectively, occur within the Northwest Forest Plan
(NWFP) Federal reserve lands, which are designed to retain and
accelerate the development of late seral characteristics. Currently,
the largest contiguous blocks of suitable coastal marten habitat occur
within the Six Rivers National Forest in the extreme northern portion
of the historical range in California, and in the adjacent Siskiyou
portion of the Rogue River-Siskiyou National Forest in the southern
portion of the historical range in Oregon. Large blocks of suitable
habitat also occur in coastal central Oregon on the Siuslaw National
Forest. Little suitable habitat is currently found in the southern half
of the historical range in California. In the coastal northern portion
of the historical range in Oregon, suitable habitat is limited to a
narrow band along the coast. Finally, in the area between the Siskiyou
and Siuslaw National Forests in the historical range in Oregon, there
is some limited amount of suitable habitat on BLM ownership. Habitat
conditions specific to each of the known extant population areas of
coastal martens are discussed below.
Distribution and Abundance of Current Known Extant Populations
There are three known extant populations of coastal martens in
coastal central Oregon, coastal southern Oregon, and coastal northern
California, according to the best available scientific and commercial
data (Figure 1; see section 8.1.2 (Delineation of Extant Population
Areas) of the Species Report (Service 2015, p. 32)). These populations
have been described as disjunct (e.g., Slauson and Zielinski 2009, pp.
35-36). Survey effort has been limited in some portions of the coastal
marten's range, however. Therefore, it is unknown whether additional
coastal martens may be found in areas that have not yet been surveyed.
In addition, a few coastal marten verifiable detections occur outside
these three population areas, but these martens are currently not
considered part of any known viable population (Slauson et al., In
prep.(a)). Surveys for martens have occurred in much of the California
portion of the historical range and suitable interior habitat in
southwestern Oregon, although minimal survey effort has occurred in
coastal central Oregon and no surveys have occurred in coastal northern
Oregon (see Figure 8.2 in the Species Report).
BILLING CODE 4310-55-P
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[GRAPHIC] [TIFF OMITTED] TP07AP15.011
BILLING CODE 4310-55-C
Coastal Central Oregon Extant Population Area
This 4,150-km\2\ (1,602-mi\2\) population area includes all
coastal-draining watersheds from the Umpqua River north to the Yaquina
River in Lincoln, Benton, western Lane, western Douglas, and
northwestern Coos Counties. Lands within this extant population area
are owned/managed by Siuslaw National Forest (41 percent), private
landowners (40 percent), Bureau of Land Management (BLM; 10 percent),
and Oregon Department of Forestry (ODF) and Oregon State Parks (9
percent). A total of approximately 2,348
[[Page 18752]]
km\2\ (907 square miles (mi\2\); 56 percent) of the extant population
area contains moderate- and high-suitability habitat (Service 2015, p.
33) for coastal martens. Of the currently available moderate- and high-
suitability habitat, 23 percent is in private ownership and 71 percent
is in Federal ownership, and 71 percent of the Federal lands are in
Reserves, which are managed for late-seral characteristics (Service
2015, p. 76). The best available information suggests that most of the
private forest land is owned by private, industrial timber companies
(Lettman 2011, p. 33).
This population area comprises approximately 20 percent coastal
marten habitat of high suitability, 36 percent of moderate suitability,
22 percent of low suitability (which has low probability of coastal
marten occurrence currently and into the future), and 21 percent
unsuitable (Slauson et al., In prep.(b)). In total, suitable marten
habitat composes 78 percent of the population area. However, we note
that the model (which used data from northwest California and southwest
Oregon) generated suitable habitat values for this population area that
did not include coastal dune habitat, which is considered suitable for
coastal martens based on visual observations and the presence of
several verifiable marten detections (Slauson et al., In prep.(a)).
Thus the amount of potentially suitable habitat for coastal martens
identified by the habitat model is an underestimate for this population
area.
Population abundance information is not available for the coastal
central Oregon population of coastal martens. Although only a single
station had been surveyed in this population area since the late 1980s,
presence/absence surveys began in this area in the summer of 2014. One
marten was detected in 2014 (Slauson et al. 2014, unpubl. data), and
six more were detected in January and February 2015; as of the time of
this publication, surveys in this area are ongoing (Moriarty 2015,
pers. comm.). The area surveyed represents only about 4 percent of the
currently delineated coastal central Oregon population area described
herein, and 2014 was the first year of survey effort in this area.
Based on the results to date and the availability of suitable habitat
in this area, it is likely that more martens will be detected in this
area as surveys continue.
Abundance or trend information is not available for any populations
of coastal martens in Oregon. Although researchers note that martens in
this area have likely declined relative to their historical condition,
they cite to insufficient historical or contemporary data to allow
evaluation of the status of martens in the coastal mountain ranges of
central and northern Oregon (Zielinski et al. 2001, p. 486). There are
no data available for estimating current population abundance or trend
for the coastal central Oregon population, and although survey efforts
recently began in this area, data from these surveys will only be
informative in terms of establishing presence or absence of coastal
martens. Zielinski et al. (2001, pp. 486-487) could only suggest that
marten numbers may be relatively low on the northern Oregon coast,
based on the absence of reported road kills along coastal Highway 101
in this area, in contrast to several road-killed martens reported from
the same highway in central Oregon. In sum, although coastal martens
have likely declined relative to their historical abundance due to the
past effects of overtrapping and timber harvest (Zielinski et al. 2001,
p. 487), there are no empirical data on which to base an estimate of
either current population abundance or trend of martens on the central
Oregon coast.
Coastal Southern Oregon Extant Population Area
This 4,696-km\2\ (1,813-mi\2\) population area includes Chetco
River, Pistol River, south Fork Rough and Ready Creek, and the North
Fork Smith River watersheds in Curry, western Josephine, and southern
Coos Counties. Lands within this population area are owned/managed by
Rogue River-Siskiyou National Forest (78 percent), private landowners
(13 percent), BLM (8 percent), and ODF (less than 1 percent). A total
of approximately 3,641 km\2\ (1,406 mi\2\; 78 percent) of the extant
population area contains moderate- and high-suitability habitat
(Service 2015, p. 35). As stated above for the coastal central Oregon
population area, present moderate- and high-suitability habitat on
private lands is expected to be harvested or not likely to retain late-
seral characteristics into the future. Of the currently available
moderate- and high-suitability habitat in the coastal southern Oregon
population area, 10 percent is private ownership and 90 percent is
Federal ownership, and 79 percent of the federally managed lands are
Federal Reserves, which are managed for late-seral characteristics
(Service 2015, p. 76). The best available information suggests that
most of the private forest land is owned by private, industrial timber
companies (Lettman et al. 2011, p. 33).
This population area comprises approximately 52 percent coastal
marten habitat of high suitability, 26 percent of moderate suitability,
17 percent of low suitability, and 5 percent unsuitable (Slauson et
al., In prep.(b)). In total, suitable marten habitat composes 95
percent of the population area.
Similar to the situation for the coastal central Oregon population,
described above, population abundance information is not available for
the coastal southern Oregon population of coastal martens. Although
extensive grid-based surveys (which are used to estimate marten
abundance or presence/absence) have not been conducted for this
population, grid-based surveys began in this area in the summer of
2014. No coastal martens were detected in 2014 (Slauson et al. 2015,
unpubl. data), but surveys just beginning at the time of this
publication have yielded a single marten detection (Moriarty 2015,
pers. comm.). The area surveyed represents only a small portion of the
currently delineated coastal southern Oregon population area described
herein, and 2014 represented the first year of survey effort in this
area. At this time, similar to the coastal central Oregon population
area, there are no empirical data on which to base an estimate of
either current population abundance or trend of martens on the southern
Oregon coast.
Coastal Northern California Extant Population Area
This 812-km\2\ (313-mi\2\) population area includes the south Fork
of the Smith River, Blue Creek, Bluff Creek, Camp Creek, Cappell Creek,
Pecwan Creek, Slate Creek, and Rock Creek (Siskiyou County, north of
Orleans, California) watersheds in Del Norte, northern Humboldt, and
western Siskiyou Counties. Lands within this population area are owned/
managed by the U.S. Forest Service (Forest Service) (Klamath National
Forest and Six Rivers National Forest; 65 percent); the Yurok Tribe of
the Yurok Reservation, California (Yurok Tribe; 23 percent); private
landowners, primarily Green Diamond Resource Company (11 percent); and
Redwood National and State Parks (1 percent). A total of approximately
656 km\2\ (253 mi\2\; 81 percent) of the extant population area
contains moderate- and high-suitability habitat (Service 2015, p. 75).
Currently present moderate- and high-suitability habitat on private
lands is expected to be harvested or not likely to retain late-seral
characteristics into the future. Of the currently available moderate-
and high-suitability habitat in the coastal northern California
population area, 11 percent is private ownership and 77
[[Page 18753]]
percent is Federal ownership, and 90 percent of the federally managed
lands are Federal Reserves, which are managed for late-seral
characteristics (Service 2015, p. 75). The best available information
suggests that most of the private land is owned by private, industrial
timber companies (Service 2014, unpubl. data).
This population area comprises approximately 67 percent coastal
marten habitat of high suitability, 14 percent of moderate suitability,
7 percent of low suitability, and 12 percent unsuitable (Slauson et
al., In prep.(b)). In total, suitable marten habitat composes 88
percent of the population area.
As reported in 1996 by Zielinski and Golightly (1996, entire), this
coastal northern California population has apparently recovered from
numbers that were once so low (in the 50 years prior to 1995) that it
was considered to be extremely rare or extinct. Martens in coastal
northern California were first surveyed to estimate abundance in 2000-
2001, and again in 2008 (Slauson et al. 2009b, p.11) and 2012 (Slauson
et al. 2014, unpubl. data). A total of 31.5 martens (95 percent
confidence interval = 24-40) were estimated for 2000-2001, and 20.2
martens (95 percent confidence interval = 11-30) were estimated for
2008, which represents a 42 percent decline in occupancy between those
two time periods (Slauson et al. 2009b, pp. 10, 11). In 2012, all
locations sampled in 2008 were resampled (Slauson et al., In prep.(a)).
Preliminary occupancy estimates for the 2012 sampling were similar to
results from 2008 (Slauson et al., In prep.(a)), suggesting no further
changes in marten population abundance in northern coastal California
between 2008 and 2012. Slauson et al. (2009b, p. 13) advised that these
population estimates should be considered minimum estimates because the
sampling area did not fully cover all potentially occupied habitats;
therefore, they suggested more realistic population estimates should be
doubled (i.e., 60 coastal martens in 2000-2001, and 40 in 2008). Based
on these samples, Slauson et al. (2009b, p. 13) concluded that as of
2008, it was likely that the entire coastal northern California
population of martens contained fewer than 100 individuals. As noted
above, subsequent survey efforts in 2012 indicated no further changes
in estimated population size since that time; therefore, the best
available data (preliminary estimates from surveys in 2012) suggest
that the current population estimate for the coastal northern
California population is similar to the estimate for 2008 (i.e., fewer
than 100 individuals).
Summary of Information Pertaining to the Five Factors
Section 4 of the Act (16 U.S.C. 1533) and implementing regulations
(50 CFR 424) set forth procedures for adding species to, removing
species from, or reclassifying species on the Federal Lists of
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of
the Act, a species may be determined to be an endangered or threatened
species based on 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; or
(E) Other natural or manmade factors affecting its continued
existence.
In making this finding, information pertaining to the coastal DPS
of the Pacific marten in relation to the five factors provided in
section 4(a)(1) of the Act is discussed below. In considering what
factors might constitute threats to a species, we must look beyond the
mere exposure of the species to a particular factor to evaluate whether
the species may respond to that factor in a way that causes actual
impacts to the species. If there is exposure to a factor but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine if that factor rises to
the level of a threat, meaning that it may drive or contribute to the
risk of extinction of the species such that the species warrants
listing as an endangered or threatened species as those terms are
defined in the Act. However, the identification of factors that could
impact a species negatively is not sufficient to compel a finding that
the species warrants listing. The information must include evidence
sufficient to suggest that these factors are operative threats that act
on the species to the point that the species meets the definition of an
endangered or threatened species under the Act.
Potential stressors that may impact coastal martens in coastal
Oregon and coastal northern California include actions that may affect
marten individuals or populations (i.e., trapping (for fur and research
purposes), predation, disease, collision with vehicles, and exposure to
toxicants) and actions that may lead to the loss, degradation, or
fragmentation of suitable marten habitat (i.e., wildfire, climate
change, vegetation management, and development). To provide a temporal
component to our evaluation of potential stressors (i.e., impacts into
the future), we first determined whether we had data available that
would allow us to reasonably predict the likely future impact of each
specific stressor over time. Where such data were available, we made
predictions of future conditions over a period of time specific to that
stressor (i.e., wildfire, climate change, as described below). If we
did not have such stressor-specific data available, we used IUCN's
standard 3-generation timeframe to assess risk (International Union for
Conservation of Nature (IUCN) 2014, pp. 14-21). Using a calculated
marten generation time of 5 years (see the Species Report for more
information on calculating marten generation time), this translated to
a timeframe of 15 years, which we used in analyzing the foreseeable
future for the majority of the stressors discussed below. This time
period allows for analysis of multiple generations of coastal martens
over a reasonable time period, as opposed to examining further into the
future where assumptions or extensive uncertainty would not allow
meaningful projections of potential future impacts.
To assess the stressor of wildfire, we used a longer future period
consisting of 30 years based on more extensive data available regarding
wildfires from the past approximate 30 years. This information was used
to predict the future equivalent level of expected fire frequency,
size, and severity. Using a longer foreseeable future timeframe for
wildfire better incorporates the range of fire-related activity that
may occur within the coastal Oregon and coastal northern California
population areas. To assess the stressor of climate change, we used a
longer foreseeable future period of 40-50 years, which coincides with
the model projection timeframes available for climate change (e.g.,
changes in temperature and precipitation) in coastal Oregon and coastal
northern California. Climate projections beyond this approximate time
period diverge with increasing uncertainty (see, e.g., Lenihan et al.
2008, pp. 16-17), including uncertainties in the magnitude and timing,
as well as regional details, of predicted climate change, especially at
smaller scales (IPCC 2015, no page number), which is why we cannot
reliably project future climate change effects beyond this timeframe.
A thorough review of each of the potential stressors is presented
in the Species Report (Service 2015, pp. 41-78), which is available on
the Internet
[[Page 18754]]
at http://www.regulations.gov, Docket No. FWS-R8-ES-2011-0105. A
summary of this information is presented below.
Each potential stressor was evaluated to determine the likely
impact to coastal martens or their habitat.
A low-level impact indicates: (1) Individual martens in
one or more populations may be impacted, but not at the population
level; or (2) minimal loss, degradation, or fragmentation of suitable
habitat.
A medium-level impact indicates: (1) Individual martens in
one or more populations are being impacted, likely resulting in a
population-level impact; or (2) moderate loss, degradation, or
fragmentation of suitable habitat.
A high-level impact indicates: (1) Individual martens in
one or more populations are being impacted, likely resulting in a
significant population-level impact; or (2) significant loss,
degradation, or fragmentation of suitable habitat.
Factor A--The Present or Threatened Destruction, Modification, or
Curtailment of the Species' Habitat or Range
Wildfire
Wildfire can impact individual coastal martens directly through
mortality (Factor E); however, fires generally kill or injure a
relatively small proportion of animal populations, particularly if they
are mobile (Lyon et al. 2000, pp. 17-20), and the best available data
do not indicate that wildfire is causing loss of individual martens. If
direct mortality of individual martens occurs, we expect the impact to
be discountable because martens are capable of rapid evacuation from an
approaching fire, and adequate suitable habitat likely exists within
their extant population areas to establish a new home range (provided
the majority of the suitable habitat within the extant population area
is not subjected to an overly large, high-severity wildfire).
Wildfire is a major disturbance force of habitat within the range
of the coastal marten in all but the wettest coastal forests and thus
has been analyzed in terms of its effect on coastal marten habitat.
Wildfire can affect the composition and structural characteristics of
the forest communities at multiple spatial and temporal scales. Fire
severity is often expressed in categories of high, medium, or low
severity, as well as mixed severity. High-severity fire, also called
stand-replacing fire, kills all or nearly all vegetation within a stand
and may extend across a landscape (Jain et al. 2012, p. 47). Medium-
severity fire refers to fire that is intermediate in its effects
between high-severity and low-severity fire; for example, a fire may
kill scattered clumps of overstory trees within a stand. Low-severity
fire burns at ground-level and does not kill most overstory trees,
although it may consume understory vegetation and downed woody debris
(Jain et al. 2012, p. 47). Finally, mixed-severity fire includes
patches of low-severity fire and patches of high-severity fire (Jain et
al. 2012, p. 47).
Regional moisture gradients result in wildfires occurring more
frequently with increasing distance from the coast and farther south in
the coastal marten's range. The effect of fire on coastal marten
habitat varies from high-severity fires that consume much or all of the
structural features (e.g., large trees, snags, logs) that are important
elements of suitable coastal marten habitat, requiring centuries to
regrow, to low-severity fires that burn only the dense, shade-tolerant
shrub layer preferred by the coastal marten (Slauson et al. 2009b, p.
11). The shrub layer likely takes 1 to 2 decades to regrow to suitable
size and density, depending on its fire resistance and adaptive
response to disturbances (Slauson 2014, pers. comm.). However, some
low-severity fires may burn ground cover without burning the dense,
shade-tolerant shrub layer preferred by the coastal marten. Wildfires
within the range of the coastal marten often burn at mixed severities
(Landscape Fire and Resource Management Planning Tools Project
(LANDFIRE) 2008a; LANDFIRE 2008b; LANDFIRE undated(a)), with some areas
within the fire perimeter burning at a high severity, resulting in
stand replacement, and other portions burning at low severity,
resulting in the loss of only ground vegetation. Fire effects are
complex; therefore, potential impacts of future wildfires on coastal
marten suitable habitat are difficult to predict.
Historical fire records indicate that, compared to the coastal
central Oregon population area, the coastal northern California and
coastal southern Oregon population areas (including adjacent or
intervening areas) have experienced larger and more severe wildfires
(Monitoring Trends in Burn Severity (MTBS; 2013, entire), both also
experiencing many small (less than 0.4 hectares (ha) (1 acre (ac))
fires. The potential for severe, stand-replacing wildfire has increased
in some areas where fire suppression and regeneration timber harvest
(i.e., the intent to develop a new stand/forest) have played a role in
raising fuel load to levels that place late-successional forest at
increased risk (Forest Service and BLM 1994b, pp. 3, 4-49). Although
fire suppression is known to contribute to the severity of wildfire in
some areas, within at least parts of coastal northern California and
coastal southern Oregon, fire suppression has had little effect on
altering the structure and composition of the dominant forest types and
has not caused an increase in high-severity fire compared to the
historical patterns (Odion et al. 2004, pp. 933-935; Miller et al.
2012, p. 200). In other words, the period of fire suppression may not
be long enough to manifest such effects in coastal forest types where
the return intervals for high-severity, stand-replacing fires are on
the order of centuries (e.g., Veirs 1982, pp. 132-133; Oneal et al.
2006, pp. 82-87).
The best available historical fire information and the more xeric
nature (i.e., environment containing little moisture) of the interior
within the Klamath Ecoregion indicate that future loss, degradation, or
fragmentation of moderate- and high-suitability coastal marten habitat
from wildfires will likely result in a greater impact in the coastal
southern Oregon and coastal northern California populations as compared
to the coastal central Oregon population. However, the more coastal
climate where most martens occur may have an ameliorating effect (e.g.,
increased humidity, reduced temperatures) on fires, reducing the size
of fires in the coastal area compared to those more characteristic of
the rest of the Klamath Ecoregion. Historical data between 1984 and
2012 indicate that wildfires burned approximately 17 percent and 42
percent of the combined moderate- and high-suitability coastal marten
habitat within the coastal northern California and coastal southern
Oregon population areas, respectively, with a few large fires
responsible for the majority of burned suitable habitat (MTBS 2013,
entire). We note that these wildfires burned at varying levels of
severity; in other words, although some suitable habitat was lost as a
result of the wildfires, varying levels of suitable habitat remain
throughout the population areas, with moderate- and high-suitability
habitat remaining within the wildfire perimeters after the fires were
extinguished (Service 2014, unpubl. Geographic Information System (GIS)
analysis).
It is possible that fire frequency, size, and severity may increase
in the future within coastal Oregon (both central and southern) and
coastal northern California, based on projected increases in
temperature and decreased precipitation (see ``Climate Change,''
below), with potentially greater
[[Page 18755]]
increases within coastal southern Oregon and coastal northern
California based on the history of wildfire within these portions of
the coastal marten's range. In contrast, little moderate- and high-
suitability coastal marten habitat has burned (historically, between
1984 and 2012) within and adjacent to the coastal central Oregon
population area (MTBS 2013, entire). Large, stand-replacing fires occur
infrequently (at intervals greater than 200 to 250 years) within
coastal central Oregon (Impara 1997, p. 92; Long et al. 1998, p. 786;
Long and Whitlock 2002, p. 223l; LANDFIRE 2008a). In general, most
fires that have recently occurred within the range of coastal marten
have burned at mixed severity (e.g., LANDFIRE 2008a; LANDFIRE 2008b;
LANDFIRE undated(a)), resulting in some areas burning at a lower
intensity with loss of only ground or shrub understory vegetation, and
retaining of a portion of the moderate- and high-quality habitat within
the fire perimeters.
In our initial development of the Species Report, we identified an
overall low-level impact across the northern portion of the coastal
marten's range, and a medium-level impact across the southern portion
of the coastal marten's range (see section 9.2.3.1 in the Species
Report). These overall impact levels were based on the probability of
occurrence of a wildfire over a 15-year time period. When considering
historical fire data over a 30-year time period to predict the future
equivalent level of expected fire frequency, size, and severity (see
Appendix A in the Species Report), the overall level of impact (i.e.,
probability of occurrence of a wildfire) is potentially the same.
However, this impact level estimate does not take into account the
historical fire data (e.g., LANDFIRE 2008a; LANDFIRE 2008b; LANDFIRE
undated(a)) that show most wildfires burned at low severity and
retained moderate- and high-quality habitat post-fire.
Based on the analysis contained within the Species Report and
summarized above, we expect that within the range of the coastal
marten, the incidence of wildfire in the future will be similar to that
recorded for 1984 to 2012. We note, however, that high-severity fires
have been infrequent in the past and are considered to remain
infrequent, overall, into the future. Our expectation is that fire
frequency, size, and severity in the future will be fairly similar (or
slightly higher in some areas based on climate change predictions).
Based on these 30 years (i.e., 1984-2012) of data, we can reasonably
estimate these effects will continue with the same approximate level of
impact into the next 30 years as has occurred over the previous 30
years (i.e., mixed severity wildfires will likely occur although most
will be low severity and retain some moderate- and high-quality habitat
post-fire); thus, we predict that, overall, these impacts do not rise
to the level of a threat. We base this conclusion on:
(1) The persistence of moderate- and high-quality habitat that has
remained following recent large wildfires (i.e., wildfires that have
burned at mixed severities (LANDFIRE 2008a; LANDFIRE 2008b; LANDFIRE
undated(a)), which have not resulted in extensive stand-replacement
within the coastal marten's range.
(2) The overall continued presence of relatively moist habitat
conditions for coastal marten habitat, primarily along the western
coast, including overall cooler, moist summer conditions that moderate
the dry conditions that promote fire ignition and spread.
(3) Information indicating that parts of coastal northern
California and coastal southern Oregon have experienced fire
suppression with little effect on altering the structure and
composition of the dominant forest types, and no increase in high-
severity fire compared to the historical patterns (Odion et al. 2004,
pp. 933-935; Miller et al. 2012, p. 200).
Climate Change
``Climate'' refers to the mean and variability of weather
conditions over time, with 30 years being a typical period for such
measurements, although shorter or longer periods also may be used
(Intergovernmental Panel on Climate Change [IPCC] 2013, p. 1,450). The
term ``climate change'' thus refers to a change in the mean or
variability of one or more measures of climate (e.g., temperature or
precipitation) that persists for an extended period, typically decades
or longer, whether the change is due to natural variability, human
activity, or both (IPCC 2013, p. 1,450). A recent synthesis report of
climate change and its effects is available from the IPCC (IPCC 2014,
entire).
Changes in climate may have direct or indirect effects on species.
These effects may be positive, neutral, or negative, and they may
change over time, depending on the species and other relevant
considerations, such as interactions of climate with other variables
(e.g., habitat fragmentation, fire frequency) (IPCC 2007, pp. 8-14, 18-
19). Typically, expert judgment and appropriate analytical approaches
are used to weigh relevant information, including uncertainty, in
various aspects of climate change.
Global climate projections are informative, and in some cases, the
only scientific information available. However, projected changes in
climate and related impacts can vary substantially across and within
different regions of the world (e.g., IPCC 2007, pp. 8-12). Therefore,
we use ``downscaled'' projections (see Glick et al. 2011, pp. 58-61,
for a discussion of downscaling) when they are available and have been
developed through appropriate scientific procedures, because such
projections provide higher resolution information that is more relevant
to spatial scales used for analyses of a given taxon. For this analysis
across the range of the coastal marten, downscaled projections are used
in addition to some regional climate models that provide higher
resolution projections using a modeling approach that differs from
downscaling. The geographic region of the projections is the southern
terminus of temperate rainforests of the North American continent,
which encompasses the range of the coastal marten.
Climate throughout the range of the coastal marten is projected
over the next approximately 40 to 50 years to become warmer, and in
particular summers will be hotter and drier, with more frequent heat
waves (Pierce et al. 2013, p. 848; Cayan et al. 2012, p. 10;
Salath[eacute] et al. 2010, p. 69; Tebaldi et al. 2006, pp. 191-200;
Hayhoe et al. 2004, p. 12423). However, the northern portion of the
coastal marten's range will likely experience winters that may become
wetter, although warmer temperatures may result in an overall water
deficit (Pierce et al. 2013, p. 848; Cayan et al. 2012, p. 10;
Salath[eacute] et al. 2010, p. 69; Tebaldi et al. 2006, pp. 191-200;
Hayhoe et al. 2004, p. 12423). The coastal marten's currently suitable
habitat may be affected by climate change to some extent. At this time,
nearly all models for the coastal northern California and coastal
southern Oregon population areas predict shifts in vegetation type over
time from conifer forest to mixed-conifer hardwood forest, as well as
shifts toward woodland and chaparral, with some shifts predicted to be
observable by 2030, but most by the end of the century (roughly 2070
through 2099) (Whitlock et al. 2003, p. 16; Rehfeldt et al. 2006, p.
1143; Lenihan et al. 2008, p. 20; Doppelt et al. 2009, p. 7; Littell et
al. 2011, pp. 11-12; Shafer et al. 2010, pp. 180-181; Littell et al.
2013, pp. 113-115). The predicted extent and nature of these shifts and
the potential rate of change vary greatly, depending on
[[Page 18756]]
potential emissions scenarios, assumptions (for example, in how various
plant species are likely to respond to changes in temperature,
precipitation, and carbon dioxide concentration), and variables
incorporated into the models. Despite these differences, most models
produce qualitatively similar forecasts of the impacts of potential
future climates on ecosystem distribution, function, and disturbances
(Shafer et al. 2010, p. 179). Although climate models have become
increasingly sophisticated, the simulated future response of ecosystems
remains subject to great uncertainty due to a number of factors,
especially over longer timeframes (see, e.g., Lenihan et al. 2008, pp.
16-17). In sum, although there is general agreement in the direction
and nature of changes anticipated, models continue to have limitations
which lead to uncertainties in the magnitude and timing, as well as
regional details, of predicted climate change, especially at smaller
scales (IPCC 2015, no page number) Thus, although we anticipate the
coastal marten's currently suitable habitat may be affected by climate
change to some extent, there is a high level of uncertainty regarding
the nature of any such effects and the likelihood and timing of their
occurrence.
In coastal central and northern Oregon, models also project shifts
by the end of this century in vegetation type from maritime conifer
forest toward mixed conifer-hardwood and deciduous forests, although
models differ in the extent of this change (Whitlock et al. 2003, p.
16; Rehfeldt et al. 2006, p. 1143; Lenihan et al. 2008, p. 20; Doppelt
et al. 2009, p. 7; Littell et al. 2011, pp. 11-12; Shafer et al. 2010,
pp. 180-181; Littell et al. 2013, pp. 113-115). These shifts in future
vegetation type may lead to range shifts for the coastal marten,
although information is not available to indicate how rapidly this may
occur. It is important to note that studies of climate change present a
range of effects including some that indicate conditions could remain
suitable for coastal martens. For example, in areas with stable or
increasing total precipitation, overall warmer temperatures are
expected to result in a decreased snowpack ((Cayan et al. 2012, pp. 20-
21; Littell et al. 2011, p. 60; Salath[eacute] et al. 2010, pp. 66-68;
Hayhoe et al. 2004, p. 12423), which would result in increased
availability of habitat for coastal martens at higher elevations, as
well as increased availability of prey during the winter months
(Service 2015, p. 7). Overall, it is not clear how finer-scale abiotic
factors may shape local climates and influence local vegetation trends
either to the benefit or detriment of coastal martens, nor is the
timeframe clear over which these influences may be realized.
We note that redwood forest habitat within coastal national and
State parks to the west of the coastal northern California population
area may remain suitable for coastal martens even with projected
changes in climate (based on a moderate emissions scenario within 50
years; DellaSala 2013, entire). However, to reach this coastal redwood
habitat, martens would need to traverse many kilometers of unsuitable
habitat (i.e., industrial timberlands). Martens actively select against
these areas that do not have protective overstory cover; however,
limited movement across unsuitable habitat areas may occur. In
contrast, coastal martens currently occurring within the drier,
interior portions of the coastal southern Oregon population area could
migrate into other suitable habitat to the west as climate change
alters the more interior habitat; a natural, westward migration is
possible due to a lack of significant physical barriers to east-west
movements within that region.
Overall, studies of climate change present a range of effects on
vegetation, including some that indicate conditions could remain
suitable for coastal martens in portions of the coastal range;
furthermore, the severity of potential impacts to coastal marten
habitat will likely vary across the range, with effects to coastal
martens potentially ranging from negative, neutral, or beneficial.
Thus, the Species Report described an estimated range of low- to
medium-impact for this stressor for coastal southern Oregon and coastal
northern California (Service 205, pp. 67-72). Modeling projections are
done at a large scale, and effects to species' habitat can be complex,
unpredictable, and highly influenced by local-level biotic and abiotic
factors. Although many climate models generally agree about the changes
in temperature and precipitation, the consequent effects on vegetation
are more uncertain, as is the rate at which any such changes might be
realized. Therefore, it is not clear how or when changes in forest type
and plant species composition will affect the distribution of coastal
marten habitat. How any such changes may in turn affect coastal marten
populations is even more uncertain. Thus, uncertainty exists when
determining the level of impact climate change may have on coastal
marten habitat. Consequently, at this time and based on the analysis
contained within the Species Report and summarized above, we have
determined that we do not have reliable information to indicate that
climate change is a threat to coastal marten habitat now or in the
future, although we will continue to seek additional information
concerning how climate change may affect coastal marten habitat.
Vegetation Management
Vegetation management includes activities such as timber harvest,
thinning, fuels reduction, and habitat restoration, which can result in
the temporary or permanent loss, degradation, or fragmentation of
suitable coastal marten habitat. Once lost, structural elements found
in suitable coastal marten habitat that are required for denning and
resting (such as large diameter live trees, snags, and logs) require
more than a century to develop (Slauson and Zielinski 2009, p. 43).
Slauson (2014, pers. comm.) anticipates that loss of the dense, shade-
tolerant shrub layer required by the coastal marten would take 1 to 2
decades to regrow.
Historically, vegetation management activities (particularly large-
scale harvest of late-successional coniferous forest habitat) reduced
the amount and distribution of suitable coastal marten habitat. At the
present time, although the reduction and fragmentation of some suitable
coastal marten habitat is expected to continue, the majority of
suitable habitat for coastal martens is currently secure and expected
to increase in the future. Habitat loss and degradation is expected to
be realized primarily on private lands, which constitute a relatively
small proportion of the suitable habitat available to martens in the
three extant population areas (23 percent in coastal central Oregon, 10
percent in coastal southern Oregon, and 11 percent in coastal northern
California). In contrast, most suitable marten habitat is in Federal
ownership (71 percent in the coastal central Oregon population area, 90
percent in the coastal southern Oregon population area, and 77 percent
in the coastal northern California population area), and the majority
of those lands are in reserve allocations under the NWFP, which are
managed for the maintenance or development of late-successional forest
characteristics (71 percent of Federal lands in reserves in coastal
central Oregon, 79 percent of Federal lands in reserves in coastal
southern Oregon, and 90 percent of Federal lands in reserves in coastal
northern California). We therefore expect not only the maintenance but
further recruitment of suitable coastal marten
[[Page 18757]]
habitat on Federal reserve lands over time.
Some vegetation management activities (such as thinning, fuels
reduction projects, and habitat restoration) have the potential to
improve habitat suitability for the coastal marten in the long term by
minimizing loss of late-successional stands due to wildfires and
accelerating the development of late-seral characteristics (Zielinski
2013, pp. 419-422). This has been suggested for a similar mustelid, the
fisher, where such activities may be consistent with maintaining
landscapes that support fishers in the long term and sometimes even the
short term, providing treatments retain appropriate habitat structures,
composition, and configuration (Spencer et al. 2008, entire; Scheller
et al. 2011, entire; Thompson et al. 2011, entire; Truex and Zielinski
2013, entire; Zielinski 2013, pp. 17-20). Thus, it is reasonable to
assume that these types of projects could increase the long-term,
overall amount, distribution, and patch size of suitable coastal marten
habitat, although some short-term degradation, loss, or fragmentation
of suitable coastal marten habitat may occur in the interim.
On lands managed for industrial timber harvest, the past and
current practice of managing coastal coniferous forests on a short-
rotation system (40-60 years) to maximize wood production has reduced
the complexity of the shrub and herb layers, which are important
components of suitable marten habitat. These management practices have
also precluded development of late-successional forest characteristics
that are important to the coastal marten (such as large diameter logs,
snags, and trees). Short-rotation forestry is prevalent on private
lands, whereas only a small fraction of forested Federal lands (i.e.,
``matrix'' lands as defined under the NWFP) may be used for timber
harvest.
Due to current and expected future intensive timber-harvesting
activities, we do not anticipate that private lands would support
viable marten populations or maintain important habitat elements in the
future. Instead, the coastal marten relies on (and our analysis
considers) the maintenance of suitable coastal marten habitat on
Federal and State lands as the key element to support the long-term
viability of coastal marten populations. Of the coastal marten suitable
habitat within the three extant population areas, from 71 to 90 percent
is on Federal lands and in reserve status under the NWFP, much of which
is managed specifically for the development of late-successional
characteristics that will be beneficial for coastal martens.
Specifically, and at present:
(1) In the coastal central Oregon extant population area, 79
percent of the habitat is considered suitable for coastal martens (56
percent moderate to high suitability). Approximately 71 percent of the
moderate- to high-suitability habitat occurs within Federal ownership,
and 71 percent of that is Federal Reserve land.
(2) In the coastal southern Oregon extant population area, 95
percent of the habitat is considered suitable for coastal martens (78
percent moderate to high suitability). Approximately 90 percent of the
moderate- to high-suitability habitat is in Federal ownership, and 79
percent of that is Federal Reserve land.
(3) In the coastal northern California extant population area, 87
percent of the habitat is considered suitable habitat for coastal
martens (81 percent moderate to high suitability). Approximately 77
percent of that is in Federal ownership, and 90 percent of that is
Federal Reserve land.
A small proportion of the moderate- and high-suitability habitat
occurs on Federal matrix lands (i.e., lands as defined under the NWFP
that are used for timber harvest). The rate of loss of late-
successional and old-growth forest on Federal lands due to timber
harvest has declined substantially since the implementation of the NWFP
(Mouer et al. 2011, entire). Although the NWFP does not recognize
marten habitat as a forest class or condition, late-successional old
growth forest likely includes a subset of coastal marten habitat (if
the necessary dense shrub layer is present).
Based on the analysis contained within the Species Report and
summarized above, including the proportion of moderate- and high-
suitability coastal marten habitat available and the favorably managed
forested lands (primarily Federal Reserves) within each extant
population area, we consider ongoing vegetation management to have a
low impact on the loss, degradation, or fragmentation of suitable
coastal marten habitat across the range of the DPS both currently and
into the future. We note that loss of suitable habitat (primarily low-
quality suitable habitat) is expected to continue to occur into the
future on private lands within all three population areas, potentially
to a greater extent in the coastal central Oregon population area due
to a larger percentage of privately-owned timber lands within that
population area. For the entire range, we considered vegetation
management as a low-level impact on moderate and high suitability
marten habitat for Federal lands, which constitute a majority of the
extant population areas, have longer harvest rotations, and retain more
structural features on the subset of that area in matrix, or where
habitat will be retained on lands in Federal Reserves. In addition,
because of the extent of Federal reserve land allocations that are
designed to maintain and develop late-successional conditions, an
unquantifiable amount of suitable habitat for coastal martens is
expected to develop in the future. Overall, potential impacts from
vegetation management do not rise to the level of a threat given the
extensive beneficial land management practices expected to continue
into the future (15 years) on public lands.
Development
Some impacts to suitable habitat are expected to occur within the
range of the coastal marten as a result of development activities such
as road building, dam construction and creation of new reservoirs,
conversion of forest habitat for agricultural use, development and
expansion of recreational areas (e.g., golf courses, campgrounds, and
trails), urban expansion, and rural development. Should these types of
disturbances occur, they would likely result in the further loss,
degradation, or fragmentation of suitable habitat. However, if these
activities occur into the future, only a small amount of habitat may be
impacted rangewide based on our evaluation of the best available data
at this time because most of the potential development is expected on
private lands that afford the coastal marten little suitable habitat to
begin with. In addition, many of the areas that provide suitable
habitat for coastal martens are areas of challenging topography that
are not conducive to intensive or large-scale development.
In Oregon, the greatest rates of change from resource land use to
more developed use occurred prior to 1984, before implementation of
county land-use plans and land-use planning laws (Oregon Administrative
Rule 660-015-00) that limit the conversion of designated resource
lands, including forest lands, to other uses (Lettman et al. 2011, p.
16). These laws encourage intensified development in areas already
urbanizing, while limiting development in more rural areas (Lettman et
al. 2009, p. 4; Lettman et al. 2011, p. 9). Consequently, conversion of
non-Federal forest land has been limited in Oregon, with 98 percent of
all non-Federal forest, agricultural, and range
[[Page 18758]]
lands in the State in 1974 remaining in those uses in 2009 (Lettman et
al. 2011, p. 11). Virtually all land-use change during this time
occurred on private land (Lettman et al. 2011, p. 11). However,
development of private land within 1.6 km (1 mi) of Federal forest land
is increasing, which can affect management along the periphery of
adjacent Federal lands, such as increasing the need for fuel treatments
on public lands to protect structures on adjacent private lands
(Lettman et al. 2009, pp. 33-34; Azuma et al. 2013, pp. 1-2).
Development of Federal forest lands in California and Oregon, however,
is expected to be limited given past history (e.g. Lettman et al. 2011,
p. 11 for Oregon) and the management mandates of the land management
agencies.
Based on the analysis contained within the Species Report and
summarized above, and similar to the vegetation management discussion
above, we estimate that development has a low impact on the loss,
degradation, or fragmentation of suitable coastal marten habitat across
the range of the DPS both currently and into the future, and thus does
not rise to the level of a threat. If development occurs, the frequency
and amount of habitat impacted may be greater in the coastal central
Oregon population area as opposed to the other two population areas due
to a larger percentage of privately-owned timber lands within the
coastal central Oregon population area. However, as exhibited over the
past 30 years, any loss is expected to be small.
Factor B--Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Trapping
Trapping for Fur
Historical unregulated fur trapping (prior to the 1930s) of coastal
martens is considered by researchers as the likely cause of the marked
contraction in coastal marten distribution. Legal marten fur trapping
in coastal northern California ended in 1946. However, fur trapping
remains legal and has continued in Oregon, and the number of martens
harvested in coastal Oregon counties has declined since the 1940s
(Zielinski et al. 2001, p. 482), although it is not known whether
trapping effort remained unchanged over this time period. By the 1970s,
martens were considered rare along the Oregon coast (Zielinski et al.
2001, p. 483; Mace 1970, pp. 13-14; Maser et al. 1981, pp. 293-294). A
total of 36 martens were harvested within coastal Oregon counties
between 1969 and 1995 (Verts and Carraway 1998, p. 409). This harvest
level excludes Lane and Douglas Counties because a substantial area of
these counties is outside the DPS and fur trapping is only reported at
the county level. The most recent data indicate that three coastal
martens were trapped within coastal Oregon during the 2013 fur trapping
season (Oregon Department of Fish and Wildlife, unpublished data).
Overall, based on these data, the number of martens trapped in coastal
Oregon has averaged fewer than two animals a year in recent decades.
The fur trapping effort for martens in Oregon is relatively minimal;
the Oregon Department of Fish and Wildlife reports that few trappers,
generally from 4 to 8, trap for marten anywhere in the State in any
given year. Most recent harvests of martens are from the Cascades and
Blue Mountain Ranges; harvest of martens in the Coast Range is
extremely rare (Hiller 2011, p. 17). Any potential population impacts
of removing individual coastal martens as a result of fur trapping are
difficult to estimate due to a lack of population size estimates in
both Oregon population areas. The best available data indicate,
however, that relatively few martens are removed from coastal
populations as a result of fur trapping in Oregon, and we have no
evidence to suggest that these populations may be in decline as a
consequence of fur trapping.
Based on the analysis contained within the Species Report and
summarized above, we consider the legal fur trapping of coastal martens
as having no overall impact to the population in coastal northern
California, as there is no legal fur trapping for martens in that
State. Fur trapping effort for martens in Oregon is relatively minimal,
and most martens harvested are not trapped in the coast ranges. We
estimate a low- to medium-level of impact to the two extant populations
in coastal Oregon, reflecting the uncertainty regarding the size of
those populations. We estimate that the impacts of fur trapping on
coastal martens in Oregon will continue at a similar level, both
currently and into the future, because the best available data do not
suggest that either fur trapping effort or impacts are likely to
change. Additionally, of note for California, we expect that nearly all
coastal martens that are accidentally captured in box traps (body-
gripping traps are illegal in California) set for other furbearer
species, or that are live-trapped for research purposes, will be
released unharmed. As a result of this best available information for
Oregon and California, we have determined that fur trapping, overall,
does not have a significant population-level impact across the DPS's
range and does not rise to the level of a threat.
Trapping for Research Purposes
Based on the analysis contained within the Species Report, we
consider the potential impacts of live-trapping and handling for
research purposes on coastal marten populations as discountable. We
came to this conclusion based on the limited distribution of marten
research projects in the three extant population areas (currently only
a single project in the western half of the coastal northern California
population area where no martens were injured or killed during live-
trapping), and based on the strict trapping and handling protocols that
must be adhered to by coastal marten researchers to ensure the safety
of study animals. Available information does not suggest that there
would be any change to the level of anticipated impacts of live-
trapping and handling for research purposes into the future, and,
therefore, we find that the potential impacts to the coastal marten
from trapping for research purposes do not rise to the level of a
threat.
Factor C--Disease or Predation
Disease
Numerous pathogens (e.g., canine distemper, canine parvovirus,
toxoplasmosis) are known to cause severe disease in mustelids. Infected
domestic dogs that are allowed to roam within an extant marten
population area could expose martens to lethal pathogens. Fur trappers
could capture an infected carnivore (e.g., marten, fisher, gray fox,
bobcat) and inadvertently spread the disease to martens through
contaminated traps. Marten researchers could also transfer lethal
pathogens within and between extant population areas if traps and
track-plate boxes are not disinfected after exposure to any carnivore
species, including coastal martens.
An outbreak of a lethal pathogen within any of the three extant
coastal marten populations could occur. Several serious pathogens have
been detected in the related fisher less than 9 km (5.6 mi) from the
nearest verifiable marten detection within the coastal northern
California population (Brown et al. 2008, entire), suggesting that
martens could be exposed by infected juvenile fishers that disperse
from their natal area into the coastal marten population area. However,
despite possible exposure to pathogens, no outbreaks of
[[Page 18759]]
diseases have been detected in coastal martens, and we have no evidence
to suggest that disease is currently present in any of the coastal
marten populations.
The best available data do not indicate that disease has impacted
coastal martens at any point in time in the past or currently. The
prevalence of past exposure to lethal pathogens within the coastal
northern California population and the coastal Oregon populations has
not been demonstrated through a serosurvey (i.e., a screening test of
the serum of a marten to determine susceptibility to a particular
disease). Additionally, if the known extant populations are disjunct
from one another, as suggested by Slauson and Zielinski (2009, pp. 35-
36), this would be beneficial in terms of reducing the ease of
transmission of disease between the populations, should an outbreak
occur. Thus, at this time, the best available data do not indicate that
a disease outbreak has had, or is likely to have, a significant
population-level effect on coastal martens.
In sum, there are currently no indications of disease in coastal
marten populations. If an outbreak of a serious disease should occur,
it could have a significant impact on the affected population. However,
based upon the best available scientific and commercial data as
presented in the Species Report and summarized here, there is a low
probability that a disease outbreak may occur. We anticipate that if
there should be an outbreak, it will likely have a low effect on all
three coastal marten populations combined, as the distance between them
makes it unlikely that the effects of such an outbreak would spread.
Thus, we have determined that disease has a low-level population impact
across the coastal marten's range and, therefore, does not rise to the
level of a threat currently or into the future.
Predation
Predation is a natural ongoing source of mortality for the coastal
marten and would not be expected to negatively impact the viability of
marten populations in coastal Oregon and coastal northern California
unless annual predation rates, combined with all other mortality
sources, exceed annual juvenile coastal marten recruitment rates
(estimated at 50 percent for the coastal marten; Slauson et al., In
prep.(a)). At this time, the only documented coastal marten predators
are bobcats (Slauson et al. 2014, unpubl. data). However, additional
predator species have been documented for other marten species and
populations:
(1) Strickland et al. (1982, p. 607) summarized reports of American
martens being preyed upon by coyotes, fishers, red foxes, cougars,
golden and bald eagles (Aquila chrysaetos, Haliaeetus leucocephalus),
and great horned owls (Bubo virginianus).
(2) Bull and Heater (2001a, p. 3) conducted a study in northeastern
Oregon and documented 18 martens (i.e., Martes caurina vulpina) killed
by predators: 44 percent by bobcats, 22 percent by raptors, 22 percent
by other martens, and 11 percent by coyotes.
Historical coastal marten predation rates are unknown, although the
historical assemblage of predator species was likely similar to the
current assemblage. It is possible that human-caused changes in
vegetation composition, vegetation distribution, and extensive road
building over time have increased predator densities and distribution
within the range of the coastal marten. These changes in vegetation and
infrastructure provide more access and avenues in which predators can
exploit their prey base, especially in forested areas that were once
undisturbed with extensive shrub cover for prey, such as martens, to
escape or find shelter. For example, in coastal northern California,
fisher and gray fox have both maintained their interior distributions
but appear to have expanded their distributions in coastal redwood
forest habitat concurrently with the dramatic decline in the
distribution of coastal martens (Slauson and Zielinski 2007, p. 242).
Another recent study within coastal northern California suggests that
bobcats and gray foxes frequent roads in forests dominated by redwoods
(Slauson and Zielinski 2010, pp. 77-78); the same is likely true for
other forest types throughout the DPS's historical range in coastal
Oregon and coastal northern California, but has not been confirmed.
Slauson and Zielinski (2010, pp. 77-78) indicate that roads may be
facilitating the presence and abundance of these predator species in
dense-shrub landscapes and increasing the risk of intraguild predation
on coastal martens. Therefore, past logging practices that reduced the
complexity of the herb and shrub layers, in combination with existing
roads, may have facilitated an increase in the distribution of
predators within the range of coastal marten, thus potentially
increasing the likelihood that coastal martens could encounter a
predator.
Predation of coastal martens has been studied recently. Since the
fall of 2012, researchers have radio-tracked up to 23 coastal martens
within the western portion of the coastal northern California extant
population area to determine survival rates and cause of death. Data
indicate a total of nine coastal marten mortalities, all killed by
bobcats (Slauson et al. 2014, unpubl. data). Although these data would
appear to indicate a 39 percent annual mortality rate, the annual
mortality rate was estimated to be 33 percent due to several martens
tracked for more than a year that were later found dead (Slauson et al.
2014, unpubl. data). The mortalities have also occurred within areas
where bobcats are considered more abundant and fishers have been
documented, particularly where extensive logging and road building
within suitable coastal marten habitat have occurred (Slauson 2014,
pers. comm.). No other records of coastal marten predation have been
documented nor conducted, including within coastal Oregon.
Predation is identified as a natural stressor (i.e., part of the
natural condition in which the coastal marten has evolved). Human
activities (such as vegetation management and road building) may
increase the abundance and distribution of predators within coastal
marten home ranges. The preliminary home ranges of all nine dead
coastal martens mentioned above contained relatively large amounts of
recently logged forest, compared with the home ranges of radio-collared
coastal martens that are still alive (Slauson 2014, pers. comm.),
suggesting that disturbed areas may result in greater predation rates
or that undisturbed areas, which harbor suitable habitat features for
escape from predators, are likely preferred. In addition, all nine dead
coastal martens were found within 100 m (328 ft) of a road. As
described in the ``Population Biology and Dynamics'' section of the
Species Report (Service 2015, p. 12), Slauson et al. (In prep.(a))
estimated annual juvenile coastal marten survival at 50 percent, which
suggests that the observed 33 percent annual mortality rate of coastal
martens from predation may be sustainable.
The population-level impact of predation within the three coastal
marten extant population areas is currently unknown. Data are available
only for the coastal northern California population where a sample of
23 individuals were radio-tracked and 9 of those were found predated
upon by bobcats, indicating a 33 percent predation rate (Slauson et al.
2014, unpubl. data). Similar information does not exist for the Oregon
populations. However, the best available scientific and commercial data
indicate that predation is occurring to an unknown
[[Page 18760]]
degree as an ongoing natural process across the range of the DPS.
As noted above, a 33 percent annual predation rate is expected to
be sustainable when compared with an annual juvenile coastal marten
survival rate of 50 percent; thus, predation would not likely result in
a population-level impact. Therefore, based on the best available data,
we find that predation has a low-level population impact for all three
extant coastal marten populations. The best available data indicate
that predation is a natural process and the level of predation is not
expected to increase in the future. Based on the analysis contained
within the Species Report and summarized above, we have determined that
predation does not rise to the level of a threat, given that it is a
natural phenomenon and appears to be occurring at a sustainable level.
Factor D--The Inadequacy of Existing Regulatory Mechanisms
Existing regulatory mechanisms that affect coastal martens include
laws and regulations promulgated by the Federal and individual State
governments. Federal and State agencies manage approximately 31 and 5
percent, respectively, of the lands within the coastal marten's range,
including a total of approximately 57 percent (13,388 km\2\ (5,169
mi\2\)) of the currently available suitable habitat (high, medium, and
low quality) throughout the range of the coastal marten (see Table 8.2
in the Species Report (Service 2015, p. 37)). Tribal governments, as
sovereign entities, have their own system of laws and regulations on
tribal lands. Principal stressors acting on coastal martens for which
governments may have regulatory control include injury or mortality due
to fur trapping, habitat modification or loss, and legal uses of
pesticides, including anticoagulant rodenticides (ARs). These
regulations differ among government entities, are explained in detail
in the Species Report (Service 2015, pp. 78-96), and are summarized
below.
Federal
All Forest Service and BLM lands within the range of the coastal
marten are managed under the NWFP, which was adopted in 1994, to guide
the management of 97,124 km\2\ (37,500 mi\2\) of Federal lands in
portions of western Washington, Oregon, and northwestern California.
The NWFP amends the management plans of National Forests and BLM
Districts within the range of the northern spotted owl (Strix
occidentalis caurina), representing a 100-year strategy intended to
provide the basis for conservation of the northern spotted owl and
other late-successional and old-growth forest-associated species
(Forest Service and BLM 1994a, 1994b). This regional plan provides for
retention and recruitment of older forests, and provides for spatial
distribution of this type of habitat that will benefit late-
successional forest-dependent species, including the coastal marten.
The amount of late-successional coniferous habitat on Federal lands
removed since implementation of the plan is substantially lower than
pre-implementation levels (Kennedy et al. 2012, p. 128). Activities
such as timber harvest and thinning, fuels reduction treatments, and
road construction (see ``Vegetation Management'' and ``Development''
under Factor A, above) may occur in certain areas known as matrix lands
(i.e., limited areas delineated specifically to allow for programmed
future timber harvest), which may result in some reduction of habitat
and habitat connectivity for the coastal marten. However, the future
loss, degradation, or fragmentation of suitable coastal marten habitat
on Federal lands from these activities is expected to be low given the
limited amount of matrix land allocation. Future increases in the
amount and distribution of forest habitat suitable for coastal martens
is expected to occur either through ingrowth in Federal Reserves, or
through forest management activities designed to accelerate the
development of late-seral characteristics within the coastal marten's
range.
The coastal marten is currently treated differently on Federal
lands in Oregon as compared to California. In Oregon, the coastal
marten is not considered a sensitive species on Forest Service and BLM
lands. However, the Forest Service (Region 6) has added the marten to
its draft sensitive species list that is expected to be finalized in
2015 (U.S. Department of Agriculture, Forest Service 2014, p. 5), and
BLM (Medford and Roseburg Districts) is also working to add the marten
to its sensitive species lists (Hughes 2015, pers. comm.). In
California, the coastal marten is a sensitive species on Forest Service
lands, but not on BLM lands. Federal protections afforded the coastal
marten as a sensitive species on Forest Service lands in California
largely depend on best management practices and conservation efforts
outlined in their Land and Resource Management Plans (LRMPs), and on-
site-specific project analyses and implementation.
Potential exposure of coastal martens to ARs has not yet been
studied, but to date we have incidental evidence of sublethal exposure
in at least one individual (see ``Exposure to Toxicants'' under Factor
E, below). The use of rodenticides is regulated under the Federal
Insecticide, Fungicide, and Rodenticide Act of 1947 (7 U.S.C. 136 et
seq.), via the registration of labels by the U.S. Environmental
Protection Agency. Each label describes the permitted use for an
individual rodenticide product and must be supported by rigorously
collected and analyzed efficacy and environmental safety data. However,
it is not clear how well those regulations prevent wildlife (including
coastal martens) exposure to legal uses of these rodenticides. Coastal
martens may also be exposed to rodenticides used illegally in the form
of rodenticide applications on illegal marijuana grow sites. Law
enforcement efforts occur in both Oregon and California in an attempt
to eradicate suspected illegal marijuana grow sites, but it is unknown
how effective such measures are at reducing the exposure of martens to
rodenticides. At this time, as described below, the best available data
do not indicate population- or rangewide-level impacts to coastal
martens from legal or illegal use of rodenticides.
The Forest Service has extensive policy on the use of rodenticides
(Forest Service Manual 2670.32), and the Forest Service Manual (Forest
Service 2005, Chapter 2600) contains legal authorities, objectives,
policies, responsibilities, instructions, and guidance needed on a
continuing basis by Forest Service line officers and primary staff to
plan and execute assigned programs and activities. In addition, BLM
policy (BLM Manual 9011-Chemical Pest Control) regulates the use of
rodenticides and other pesticides on their ownership. Queries to the
BLM and Forest Service in Oregon confirm they do not use anticoagulant
rodenticides on their ownership, although some use of strychnine for
rodent control is employed on Forest Service land (Standley 2013, pers.
comm.; Bautista 2013, pers. comm.).
States of Oregon and California
Forest practice rules vary greatly between Oregon and California,
with no explicitly stated coastal marten protections specified in
either State. However, retention of some number of snags and green
trees in harvest units is a ubiquitous requirement in managed forests
throughout the range of the coastal marten (State, Federal, and private
lands) (e.g., Oregon forest practice rules (Oregon Administrative Rules
(OAR) Chapter 629, Division 600); CAL FIRE forest practice rules (Title
14, California Code of Regulations, Chapters
[[Page 18761]]
4, 4.5, and 10; Forest Service and BLM 1994a, 1994b)). The coastal
marten is not listed under the California Endangered Species Act (CESA)
or as a State ``fully protected'' species and thus does not receive
protections available under those statutory provisions. In terms of
effects to coastal marten habitat or incidental harm to coastal martens
from timber harvesting or other types of land-disturbing projects, the
State of California has existing regulations that act in combination to
disclose, avoid, or mitigate environmental degradation, the latter two
situations of which could potentially result in benefits to coastal
marten habitat. Cumulative effects analyses for listed and non-listed
species, such as coastal marten, are required in both the California
Environmental Quality Act (CEQA) and the California forest practice
rules.
Structures that are retained (e.g., some level of snags and green
trees) under existing forest practice rules typically do not meet the
minimum size used by coastal martens (Schmidt 2014, pers. obs.; Slauson
2014, pers. obs.). Where these features are large enough, they may
provide future denning and resting sites provided they have the
appropriate structural attributes (such as cavities and large limbs)
and the surrounding forest is allowed to develop the necessary canopy
cover, dense shrub understory, and prey base to support coastal martens
in the long term. Short rotations of industrial forest management
rarely allow this to happen, as compared to areas where management is
for longer rotations or designed to develop older stands (e.g., old-
forest structure management on Oregon State Forests) that retain these
legacy features that may facilitate coastal marten habitat development.
Protection measures for riparian areas are also a widespread
standard on managed forests throughout the range of the coastal marten,
with larger buffers and more stringent timber retention requirements
typically provided on Federal and State lands as compared to private
lands. Retention areas to meet other management goals are also found
across ownerships (e.g., anchor habitats on Oregon State Forests,
occupied site buffers on multiple ownerships, Watercourse and Lake
Protection Zones on private land in California). Although many of these
retained areas are not large enough to support a coastal marten home
range, they do provide patches of structural features that may allow
coastal marten movement across the landscape and facilitate dispersal
between larger blocks of coastal marten habitat. This may be
particularly valuable where State lands lie between large blocks of
Federal lands managed as late-seral habitat. Additionally, the Oregon
Department of Forestry calls for managing 30 to 50 percent of their
State Forests in northwest Oregon for layered and old-forest structural
conditions such as larger trees, multiple canopy layers, diverse
understories and shrub layering, and diverse structural features such
as downed wood and snags (ODF 2010, pp. 4-48, C-1 to C-24). These lands
represent a small proportion of currently occupied habitat and are
mostly located outside of existing coastal marten population areas;
however, these areas may benefit coastal martens in the future as they
are allowed to develop into a structural condition more suitable to
martens.
Coastal martens can be legally harvested/trapped for fur in Oregon
but not in California (see ``Trapping'' under Factor B, above). Within
Oregon, coastal martens are listed (by the Oregon Department of Fish
and Wildlife) as a sensitive species in the vulnerable category and as
a species of conservation concern, but neither of these designations
has associated regulatory mechanisms. Rather, these designations are
used to encourage voluntary actions to improve a taxon's status or
prevent population declines. Within California, coastal martens may not
be intentionally harvested or trapped for fur or otherwise killed in
California; although injury or mortality may occur when coastal martens
are incidentally captured in traps set for other species, we expect
incidental captures to be released unharmed. The use of body-gripping
traps is prohibited and enforced in California, but injury or mortality
of coastal martens is likely to occur during illegal fur trapping using
the banned body-gripping traps. The extent of illegal fur trapping and
mortality of coastal martens in Oregon and California is unknown. In
general, legal trapping (such as that for research) is unlikely to
result in injury or mortality to coastal martens because of the
mandatory use of live traps and strict trapping and handling
procedures.
Summary of Factor D
Overall, existing Federal and State land-use plans include some
general conservation measures for northern spotted owl habitat that are
not specific to coastal martens but nonetheless provide a benefit to
the coastal marten, for example through the maintenance and recruitment
of late-successional forest and old-growth habitat. Most management
plans address structural habitat features (e.g., snags or downed wood
retention) or land allocations (e.g., Oregon Department of Forestry's
no-cut riparian buffer; NWFP's protections of a network of late-
successional forest habitat connected by riparian reserves) that
contribute to the coastal marten's habitat. These land-use plans are
typically general in nature and afford relatively broad latitude to
land managers, but with explicit sideboards for directing management
activities. Federal regulatory mechanisms have abated the large-scale
loss of late-seral coniferous forest habitat. Much of the land in
Federal ownership across the range of the coastal marten is managed for
interconnected blocks of late-successional forests that are likely to
benefit martens. Timber harvest has been substantially reduced on
Forest Service and BLM lands within the NWFP area, and existing
management is designed to maintain or increase the amount and quality
of late-successional or old-growth forest that provides marten habitat
and aids in connecting populations. Management of State lands for
scattered parcels of older forest or habitat retention for other late-
successional species may also facilitate coastal marten movements
across the landscape or provide future habitat as some areas are
allowed to develop into older stands. Outside of public (State and
Federal) ownership, forest practice rules provide no explicit
protection for martens and limited protections for habitat of value to
martens. While some structural retention and limited buffers may retain
structural features desirable for martens on private lands, the short
harvest-rotation periods reduce the likelihood that the surrounding
stand will develop to a condition that makes these features suitable
for long-term use by martens.
Based on the analyses contained within the Species Report (Service
2015, pp. 81-94) and summarized above on the existing regulatory
mechanisms for the coastal marten, we conclude that the best available
scientific and commercial information does not indicate that the
existing regulatory mechanisms are inadequate to address impacts to
coastal martens from the identified stressors.
Factor E--Other Natural or Manmade Factors Affecting the Continued
Existence of the Species
Collision With Vehicles
Collision with vehicles is a known source of mortality for coastal
martens currently and is expected to continue into the future, given
the presence of roads within the range of the DPS. A low density of
roads with heavy traffic traveling at high speeds (greater than 45
miles per hour) and infrequent reports of road-killed martens within
all three
[[Page 18762]]
extant population areas suggest that few martens die from vehicle
collisions each year.
No coastal marten road kill mortalities have been reported recently
(since 1980) from within the coastal southern Oregon and coastal
northern California population areas, both of which are areas that do
not contain long segments of heavily used highway (although it is
possible that road kill on any light-use roads in remote areas may not
be discovered by humans before being consumed as carrion). A total of
14 coastal marten mortalities have been documented from vehicle
collision since 1980 (over a 34-year period) within or near the coastal
central Oregon population area, suggesting a low annual mortality rate
from vehicle collisions. Collisions with vehicles were and continue to
be expected within the coastal central Oregon population because of the
presence of U.S. Highway 101 within this population.
We expect that in the future a small number of coastal martens will
be struck by vehicles, especially dispersing juvenile coastal martens
that must reach unoccupied suitable habitat for establishment of a home
range. However, the best available information does not suggest any
significant increases in vehicular traffic or new highways (consistent
with the information available on potential development-related impacts
(see ``Development'' under Factor A, above)) to be built in areas where
martens occur. Therefore, we conclude the impact of vehicle collisions
on coastal martens to continue at similar levels into the future. Any
potential population impacts from individual coastal marten mortalities
as a result of collisions with vehicles are difficult to estimate; we
have no evidence of mortalities due to collisions with vehicles in the
coastal northern California or coastal southern Oregon populations, and
lack any population size estimate for the coastal central Oregon
population area where some mortalities have been documented over an
extended period of time. The best available data indicate, however,
that across the DPS relatively few coastal martens are killed as the
result of collisions with vehicles. Based on the information presented
above and in the Species Report (Service 2015, pp. 52-53), we find that
collision with vehicles presents a low-level impact on all three
coastal marten populations (i.e., impacts to individual coastal martens
as opposed to populations); therefore, this stressor does not rise to
the level of a threat.
Exposure to Toxicants
An emerging stressor to coastal martens is the widespread use of
anticoagulant rodenticides (ARs) and other pesticides (e.g.,
organophosphates, carbamates, or organochlorines) at both legal and
illegal marijuana grow sites, and the potential individual- and
population-level impacts to species, including coastal martens, that
are exposed to toxicants at these sites. We note that recent efforts to
determine the prevalence of ARs in carnivore populations have focused
on fisher populations in California due to the conservation status of
that species and because marijuana grow sites are common in California.
As information specific to coastal martens is largely lacking, for the
purposes of the analysis in our Species Report (Service 2015, pp. 54-
61), we examined this fisher information to help evaluate the potential
impacts ARs might have on coastal marten populations in coastal
northern California and coastal Oregon.
Anticoagulant rodenticides were created to kill small mammals
considered pests, including commensal rodents such as house mice (Mus
musculus), Norway rats (Rattus norvegicus), and black rats (R. rattus)
in and around residences, agricultural buildings, and industrial
facilities, and agricultural pests such as prairie dogs (Cynomys sp.)
and ground squirrels (Spermophilus sp.) in rangeland and near crops.
Anticoagulant rodenticides bind to enzymes responsible for recycling
vitamin K, thus impairing the animal's ability to produce several key
blood clotting factors (Berny 2007, p. 97; Roberts and Reigart 2013,
pp. 173-174).
Anticoagulant rodenticide exposure is manifested by such conditions
as bleeding nose and gums, extensive bruises, anemia, fatigue, and
difficulty breathing. Anticoagulants also damage the small blood
vessels, resulting in spontaneous and widespread hemorrhaging. There is
often a lag time of several days between ingestion and death, if lethal
doses are ingested (Berny 2007, pp. 97-98; Roberts and Reigart 2013,
pp. 174-175). Evidence from laboratory and field studies for several
mammalian and avian species suggests that various pesticide (including
rodenticide) exposures:
(1) Reduce immune system function (Repetto and Baliga 1996, pp. 17-
37; Li and Kawada 2006, entire; Zabrodskii et al. 2012, p. 1);
(2) Are associated with a higher prevalence of infectious disease
(Riley et al. 2007, pp. 1878, 1882; Vidal et al. 2009, p. 270);
(3) Cause transient hypothermia (Ahdaya et al. 1976, entire; Gordon
1984, p. 432; Grue et al. 1991, pp. 158-159), which may contribute to
an increase in mortality rates (Martin and Solomon 1991, pp. 122,126);
or
(4) Possibly impair an animal's ability to recover from physical
injury (Erickson and Urban 2004, pp. 90, 100, 184, 188, 190-191).
Exposure to ARs, resulting in death in some cases, is documented in
many mammalian predators (e.g., Alterio 1996, entire; Shore et al.
1999, entire; Riley et al. 2007, entire; Gabriel et al. 2012, entire;
Quinn et al. 2012, entire), but such information is unavailable for
coastal martens. However, there is wide variability in lethal and
sublethal levels of ARs exhibited among and within taxonomic groups
(Gabriel et al. 2012, p. 11), and it is unknown if stressors or
injuries could predispose all species to elevated mortality rates
(e.g., Gabriel et al. 2012, p. 10 for fishers). In one California study
of two fisher populations, the majority (84 percent) of fishers
(closely related to martens) tested positive for the presence of ARs,
but at sublethal levels (Thompson et al. 2013, p. 6; Gabriel et al.
2012, p. 5). Additionally, several fishers have recently been confirmed
to have died from acute poisoning from ARs on the Hoopa Reservation
(Gabriel et al. 2012), which is located less than 9 km (5.6 mi) south
of the coastal marten's extant population area in coastal northern
California. However, Gabriel et al. (2012, p. 6) determined that AR
exposure was the direct cause of death for only a small proportion (4
of 58 individuals found dead within 2 isolated California populations)
of those fishers examined.
Little information exists specific to coastal marten exposure or
response to ARs. Coastal martens within the California population and
likely the coastal Oregon populations may be exposed to ARs currently
or in the future in those areas where marijuana grow sites are located
(which currently is known to be a fraction of the coastal marten's
range) based on: (1) The proximity of the closely related fisher with
confirmed exposure to ARs, including in areas as close as 9 km (5.6 mi)
from the coastal northern California population; (2) the broad use of
ARs at illegal marijuana cultivation sites, which have been documented
to occur within or adjacent to portions of both the marten's coastal
northern California and coastal southern Oregon population areas; and
(3) the potential continued use of ARs at legal grow sites and other
areas within the range of the coastal marten where agricultural
pesticide use
[[Page 18763]]
occurs. Although the presence or use of ARs is documented in many areas
throughout coastal northern California and into portions of Oregon
(Higley et al. 2013, p. 2; Oregon High Intensity Drug Trafficking Area
2013, entire), to date, only one record of a positive exposure exists
within the range of coastal martens that demonstrates exposure to ARs.
This information was obtained from non-related, coincidental research
occurring in the coastal northern California extant population area in
2014; of six coastal martens assessed, one tested positive for AR
exposure with a sublethal concentration (Slauson 2014, unpubl. data).
The individual that tested positive was confirmed killed by a bobcat.
It is unknown whether the sublethal dose of ARs may have predisposed
that coastal marten to predation. This information about potential
exposure of coastal martens to ARs was collected on private lands and
involved a small sample size (six coastal marten individuals) in one
portion of the coastal northern California extant population area;
thus, it is not necessarily representative of the levels of exposure
throughout other land ownership areas within the remainder of the DPS.
The sublethal AR exposure of this single coastal marten is the only
data available to us regarding potential exposure of coastal martens to
ARs; the best available information does not indicate any population-
or rangewide-level impacts of AR exposure on coastal martens.
Overall, illegal and legal marijuana cultivation sites (and use of
ARs and other pesticides) are present within or near all three coastal
marten populations, although the probability of exposure varies between
them. At this time we estimate that the prevalence of illegal marijuana
cultivation sites (based on data associated with eradicated cultivation
sites) occurs within approximately 5 percent of the coastal central
Oregon population area, 25 percent of the coastal southern Oregon
population area, and 40 percent of the coastal northern California
population area (Service 2014, unpubl. data). However, the incidence of
toxicant exposure that may result for coastal martens and the potential
population-level effects are largely unknown given testing for exposure
to ARs began only recently. We note significant uncertainty as to the
severity of impact that this stressor may have at the population- and
rangewide levels on coastal marten given that the best available data
are minimal regarding potential exposure to this stressor and any
consequent effects on coastal martens at this time, including the lack
of information regarding potential sublethal effects. There are few
samples to fully determine coastal marten exposure rates to ARs, and no
tests on martens to determine sublethal exposure rates and effects. The
recent legalization of marijuana in the State of Oregon adds an
additional element of uncertainty to evaluation of this stressor, as it
is unknown whether or how this may potentially affect exposure rates
(for example, whether there may be a trend toward indoor grow
operations, which would potentially reduce exposure of wildlife to
ARs). Based on the analysis contained within the Species Report and
summarized above, we find the population-level impact from exposure to
toxicants to be low both currently and into the future, although a
higher (medium-level) impact may occur for the coastal northern
California population as a result of higher prevalence of illegal
marijuana cultivation sites. The best available information does not
suggest that these impacts rise to the level of a threat, primarily
based on the available information on levels of known marten exposure
to ARs and lack of evidence that ARs are having a population-level
effect.
Small and Isolated Population Effects
Small, isolated populations are more susceptible to impacts
overall, and relatively more vulnerable to extinction due to genetic
problems, demographic and environmental fluctuations, and natural
catastrophes (Primack 1993, p. 255). That is, the smaller a population
becomes, the more likely it is that one or more stressors could impact
a population, potentially reducing its size such that it is at
increased risk of extinction. We therefore evaluated information
suggesting that the currently known populations of coastal martens may
be small or isolated from one another to the degree that such negative
effects may be realized in the DPS.
The best available data suggest coastal marten distribution has
contracted markedly in California and southern Oregon since the early
20th century. At present there are three known extant populations of
coastal martens in California and Oregon; however, much of coastal
Oregon has not been systematically surveyed. Of these known
populations, the coastal northern California population is the only
population for which size estimates are available. Based on multi-state
occupancy modeling, Slauson et al. (2009b, p. 13) estimated that the
abundance of coastal martens in the coastal northern California
population area is low (i.e., fewer than 100 individuals in 2008).
Comparing areas sampled in 2008 to those sampled in 2000 to 2001,
sample unit occupancy had declined by an estimated 42 percent (Slauson
et al. 2009b, p. 10). Whether this change may have been part of a
natural population fluctuation or was related to human-caused factors
is unknown (Slauson et al. 2009b, p. 14). Although small in size,
preliminary occupancy estimates for 2012 (which are unchanged from
2008) suggest no further changes in marten population abundance
(Slauson et al. 2014, unpubl. data).
The abundance and trend of coastal marten populations in coastal
Oregon is unknown; standardized survey efforts for martens in central
and southern Oregon began in 2014. In the coastal central Oregon
population area, at least one marten was detected in 2014, and six
martens have been detected in 2015 in the first weeks of surveys
(Moriarty 2015, pers. comm.). In addition, surveys just beginning in
southern coastal Oregon have yielded a marten detection (Moriarty 2015,
pers. comm.). Surveys are continuing at the time of publication of this
document.
Slauson and Zielinski (2009, p. 36) describe the three known extant
coastal marten populations as disjunct. Verified marten detections have
clustered into the three extant population areas recognized in this
document, which are geographically separated. The degree of functional
connectivity between the known populations is not well understood due
to insufficient survey effort in many areas, particularly in coastal
Oregon (Service 2015, p. 29). There are some detections of martens
occurring between the coastal northern California and coastal southern
Oregon populations (Service 2015, p. 31, Figure 8.2(B)). Habitat
modeling suggests connectivity of suitable habitat between these
populations (Service 2015, pp. 25-26), and there are no known barriers
to dispersal between them. Suitable habitat is more limited and of
lower quality between the coastal southern Oregon and coastal central
Oregon populations, but not entirely discontinuous (Service 2015, pp.
25-26). Survey efforts have also been more limited in this area to date
(Service 2015, p. 29). Marten surveys are largely lacking from coastal
central and coastal northern Oregon, although habitat modeling suggests
conditions suitable for additional martens that could support the
existing known populations (Service 2015, p. 29-30, 34).
[[Page 18764]]
Surveys designed to determine potential occupancy by coastal
martens (for example, targeting areas of suitable habitat large enough
to support multiple home ranges) may not necessarily detect animals
moving between populations. Although not equivalent in function to
large areas of contiguous habitat, fragmented patches of forest
sufficient to provide corridors for dispersal of individuals can play
an important role in maintaining assemblages of old-growth forest
mammals (Perault and Lomolino 2000, pp. 418-419). The potential habitat
connectivity between known populations of coastal martens and their
capacity to travel long distances at least on occasion suggests that
the geographically disjunct nature of coastal marten populations is not
necessarily a barrier resulting in isolation. As described earlier, the
majority of juvenile martens disperse relatively short distances from
their natal areas, generally less than 15 km (9.3 mi) (Phillips 1994,
pp. 93-94). The distance between known extant coastal marten
populations exceeds the mean maximum juvenile dispersal distance for
martens in general (15 km (9.3 mi); Phillips 1994, pp. 93-94). The
distance between known extant populations exceeds this distance, but is
within the maximum observed dispersal capability of martens, ranging
from 40 to 80 km (25 to 50 mi) (Thompson and Colgan 1987, pp. 831-832;
Broquet et al. (2006, pp. 1690, 1695), up to 149 km (92 mi) or greater
(Slough 1989, p. 993; Kyle and Strobeck 2003, p. 61). The relatively
continuous extent of some limited area of marten habitat, though much
of it is low in quality, and dispersal capabilities of martens
indicates that movement between coastal marten populations is possible,
acknowledging that individuals seeking to traverse areas of
regenerating forest face reduced probability of survivorship (Johnson
et al. 2009, p. 3366). For this reason, areas that may provide for safe
corridors of movement, such as riparian areas retained under State
forest practice rules (see Factor D, above), may play an important role
in facilitating connection between larger areas of suitable habitat for
coastal martens.
In most cases, genetic interchange need occur only occasionally
between populations (a minimum of 1 migrant per generation, possibly up
to 10) to offset the potential negative impacts of inbreeding (e.g.,
Mills and Allendorf 1996, entire; Wang 2004, entire). In addition,
depending on population sizes and the distance between them, the
ability of even a few individuals to move between population areas can
preserve the potential for recolonization or augmentation (Brown and
Kodric-Brown 1977, entire). Genetic evidence from studies of martens in
fragmented landscapes suggests that despite separation of populations
by large distances, up to several hundred kilometers, little genetic
differentiation is observed (Broquet et al. 2006, p. 1690, citing Kyle
and Strobeck 2003, pp. 60-61). Broquet et al. (2006, p. 1690) suggest
this weak genetic structure is indicative of great dispersal capacity
in martens, and their results suggest that a few successful long-
distance dispersers create enough gene flow in marten populations to
significantly reduce genetic differentiation that might otherwise
result from isolation by distance (Broquet et al. 2006, p. 1695).
Based on all of these consideration, despite the relatively
geographically disjunct nature of the known extant marten populations,
we do not have evidence to suggest that the populations are likely
entirely isolated from one another to the degree that we would expect
the manifestation of significant negative effects that could
potentially arise in small, isolated populations, such as inbreeding
depression. We recognize that habitat quality and contiguity could be
improved between the extant population areas, and indications are that
habitat recruitment through management of Federal lands under the NWFP
should contribute to improved connectivity. Despite room for
improvement, at this point in time, the best available information
suggests that the extant population areas are within the dispersal
capabilities of martens and the habitat suitability model indicates
some connectivity between populations, at least sufficient to provide
for occasional genetic interchange. We note that more detailed
information is needed regarding the size and demographics of coastal
marten populations, as well as the capability of intervening areas of
habitat to support dispersing individuals, in order to fully understand
whether the known populations are faced with any challenges as a result
of the present degree of connectivity between them.
Although coastal martens are likely reduced in abundance or
distribution relative to their historical numbers and range, there is
no empirical evidence that any current populations of coastal marten
are in decline. Based upon the analysis contained within the Species
Report and summarized above, the best available information indicates
that the coastal northern California population totals fewer than 100
individuals (Slauson et al. 2009b, p. 13). Although small in size, the
estimated number of individuals that comprise the coastal northern
California population of martens appears to have remained the same in
recent years based on survey data collected since 2008.
Abundance and trend estimates are not available for the two coastal
Oregon populations, so it is unknown whether these populations might be
considered small. Coastal martens have likely been reduced in abundance
relative to their historical numbers, although Zielinski et al. (2001,
p. 487) suggest that out of the three west coast States, coastal
martens are likely most common in Oregon. These researchers note,
however, an inability to evaluate the status of martens in the coastal
mountain ranges of central and northern Oregon due to insufficient
historical or contemporary data (Zielinski et al. 2001, p. 486). Data
from systematic surveys continue to be limited or nonexistent in
coastal northern and coastal central Oregon, leading to an inability to
determine population size, trend, or distribution in these areas at
this time. However, as noted above, recently initiated surveys in
coastal central and coastal southern Oregon did result in seven total
detections of coastal martens in the first weeks of effort in 2015
(Moriarty 2015, pers. comm.), and surveys are continuing at the time of
this publication (Moriarty 2015, pers. comm.).
The three known extant populations of coastal martens are disjunct.
While this characteristic does have some potential negative effects
(e.g., potential impacts from other stressors may be exacerbated),
overall it places the DPS at a diminished risk of extinction due to
small population size effects (known small population for coastal
northern California and unknown for coastal Oregon populations) because
it is unlikely that any stressor will simultaneously affect all three
populations. In addition, although the populations may be
discontinuous, we do not have evidence to suggest that populations are
entirely isolated beyond the potential dispersal range known for
martens such that negative small population effects are likely to be
realized. Therefore, based on the best available data, we have
determined that small or isolated population size effects do not rise
to the level of a threat either currently or in the future.
Cumulative Effects
We estimate the potential impact of each stressor described above
acting alone on coastal marten individuals, populations, and suitable
habitat. However, coastal marten populations and suitable habitat can
also be affected
[[Page 18765]]
by all stressors acting together or some of the identified stressors
acting together (particularly medium-level impacts, as described in
detail in the Species Report and summarized above). The combined
effects of those stressors could impact populations or suitable habitat
in an additive or synergistic manner. Any given stressor could impact
individuals, a portion of a population, or available suitable habitat
to varying degrees or magnitude, and alone, a stressor may not
significantly impact coastal martens or their habitat.
Based on our analysis of all stressors that may be impacting
coastal martens or their habitat, including, to be conservative, taking
into account effects associated with potential small or isolated
populations (noting that the coastal northern California population is
known to be small and information is not available to indicate if the
coastal Oregon populations may be small), it is likely that if any
cumulative impacts occur, they would do so under the following three
scenarios:
(1) A projected increase in the frequency and size of wildfires
within the coastal southern Oregon and coastal northern California
portions of the DPS's range due to climate change model projections of
a warmer, drier climate in the future, which could also change
vegetation structure.
(2) A potential increase in coastal marten mortality rates from
predation, disease, fur trapping in Oregon, and collision with vehicles
due to reduced marten fitness after sublethal exposure to toxicants
found at marijuana grow sites, although levels of exposure remain
unknown.
(3) Increased coastal marten predation rates due to an increased
abundance of intraguild predators (e.g., bobcats, fishers) resulting
from vegetation management activities that improve habitat suitability
for these marten predators by decreasing shrub densities.
Here we consider the impacts of each of these potential cumulative
effect scenarios:
Models of climate change predict potential increases in wildfire
frequency and size within the coastal southern Oregon and coastal
northern California portions of the DPS. As described in our analysis
in ``Wildfire'' under Factor A, above, we expect that wildfire impacts
are likely to occur throughout the range of the coastal marten at a
level similar to the historical impacts that have occurred within each
extant population area between 1984-2012 (roughly 30 years), and we
expect that fire frequency, size, and severity in the future will be
fairly similar or slightly higher in some areas based on climate change
projections. Based on these 30 years of data, we can reasonably
estimate that these effects will continue with the same approximate
level of impact throughout the DPS into the next 30 years, although
they may be slightly higher in the coastal southern Oregon and coastal
northern California population areas. Additionally, we do not have
information that climate change will result in vegetation changes that
will make significant portions of currently occupied coastal marten
habitat unsuitable. Therefore, the best available data at this time do
not suggest that the cumulative effects of wildfire and climate change
rise to the level of a threat to the DPS overall for the following
reasons:
(1) Although climate change models generally predict warmer, drier
conditions in the future, the coastal marten primarily inhabits forests
that are relatively less vulnerable to such changes. The overall
continued presence of relatively moist habitat conditions for coastal
marten habitat, primarily along the western coast, including overall
cooler, moist summer conditions, moderate the dry conditions that
promote fire ignition and spread.
(2) Moderate- and high-quality habitat for coastal martens has
remained following recent large wildfires (i.e., wildfires that have
burned at mixed severities (LANDFIRE 2008a; LANDFIRE 2008b; LANDFIRE
undated(a))); these fires have not resulted in extensive stand-
replacement within the coastal marten's range.
(3) Neither adverse changes to coastal marten habitat through
potential vegetation changes nor the loss of habitat from future
wildfires is expected to be significant, nor is the combined effect of
these two potential stressors.
Sublethal effects of anticoagulant rodenticides have been
demonstrated for many species (see discussion in the Species Report
(Service 2015, p. 57)), and can include reduced blood clotting
abilities and excessive bleeding. Sublethal exposure to ARs has been
shown to make individuals of non-mustelid mammals more susceptible to
environmental stressors such as adverse weather, food shortages, and
predation (Erickson and Urban 2004, p. 99; Jaques 1959, p. 851; Cox and
Smith 1992, p. 169; Brakes and Smith 2005, p. 121; LaVoie 1990, p. 29),
potentially predisposing individuals to death from other causes.
However, there is wide variability in lethal and sublethal levels of
ARs exhibited among and within taxonomic groups (Gabriel et al. 2012,
p. 11), and it is unknown if stressors or injuries could predispose all
species to elevated mortality rates (e.g., Gabriel et al. 2012, p. 10
for fishers). While it is possible that these effects could occur for
coastal martens, the best available data at this time do not support a
conclusion that the cumulative effects of rodenticides (which may occur
at relatively few sites within the extant population areas and thus
reduce likelihood of exposure) combined with other environmental
stressors rise to the level of a threat to the DPS overall. Relatively
few marijuana grow sites have been found within the extant population
areas (which reduce likelihood of exposure), there are too few samples
to determine coastal marten exposure rates to ARs, and no tests have
been conducted on martens to determine sublethal exposure rates and
effects. Furthermore, none of the data available (related to exposure
and potential lethal or sublethal effects) demonstrate an effect
leading to current or future population declines.
Vegetation management activities that reduce the shrub layer that
coastal martens rely on could also provide increased suitable habitat
for marten predators, such as bobcats, resulting in potential increased
levels of predation on coastal martens. In general, however, we expect
such vegetation management activities would be restricted primarily to
private lands. As discussed above (see Summary of Species Information,
above), the majority of the area known to be occupied by coastal
martens is composed of Federal lands, and most of these Federal lands
are in reserves managed under the standards and guidelines of the NWFP.
As these areas are under management for the protection or enhancement
of late-successional forest characteristics, we do not expect extensive
management activities on these lands to reduce shrub densities and thus
potentially result in increased abundance of intraguild predators.
Reduced shrub densities as a result of vegetation management on private
lands may pose an increased risk of predation to individual coastal
martens seeking to disperse through such areas, which poses some
challenges in terms of maintaining or developing connectivity between
populations. Although a potential reduction in the complexity of herb
and shrub layers on these private lands is likely to continue and thus
potentially result in increased suitable habitat for marten predators,
these vegetation changes are expected to be offset by the continued
maintenance and enhancement of significant portions of suitable habitat
on forested reserves throughout the range of the coastal marten. Thus,
at this time, cumulative
[[Page 18766]]
effects of potential vegetation management activities and predation do
not rise to the level of a threat to the DPS overall.
In summary, the best available scientific and commercial data at
this time do not show that combined impacts of the most likely
cumulative impact scenarios are resulting in significant individual- or
population-level effects to the coastal marten, including when taking
into consideration small population size, where known. Although all or
some of the stressors could potentially act in concert as a cumulative
threat to the coastal marten, there is ambiguity in either the
likelihood or level of impacts for the various stressors at the
population or rangewide level, or the data indicate only individual-
level impacts. There is little doubt that coastal marten populations
today are smaller and their range has been reduced compared to
historical conditions, which potentially increases the vulnerability of
the coastal marten to potential cumulative low- or medium-level
impacts. However, the best available information does not provide
reliable evidence to suggest that current coastal marten populations
are experiencing population declines or further reductions in
distribution, which would be indicative of such impacts. Thus, the best
available scientific and commercial data do not indicate that these
stressors (including consideration of effects associated with
potentially small or isolated populations, to be conservative) are
cumulatively causing now or will cause in the future a substantial
decline of the total extant populations of the coastal marten across
its range. Therefore, we have determined that the cumulative impacts of
these potential stressors do not rise to the level of a threat.
Conservation Efforts
The Humboldt Marten Conservation Group (HMCG) was formed in 2011,
with the primary goal of developing a conservation assessment and
strategy for the [then described] Humboldt marten subspecies (Martes
americana humboldtensis) in coastal northern California. A memorandum
of understanding (MOU) was signed on September 26, 2012, between the
Service, Six Rivers National Forest, the U.S. Forest Service Pacific
Southwest Research Station, Redwood National and State Parks,
California Department of Fish and Wildlife (CDFW; formerly California
Department of Fish and Game (CDFG)), California Department of Parks and
Recreation (CDPR), the Yurok Tribe, and the Green Diamond Resource
Company (Service 2012, entire). Each signatory party designated two or
more members to provide input to the conservation assessment and
strategy, and to guide future implementation of priority conservation
actions, irrespective of land ownership. In January 2014, an Oregon
stakeholder group was formed to work with the HMCG to extend
conservation efforts for the coastal marten into Oregon. This informal
group includes participation from Federal, State, timber, and tribal
interests.
The HMCG is cooperatively developing a conservation strategy to
address coastal marten population and habitat needs across its range,
including the goal of increasing the abundance and distribution of
coastal martens through habitat retention, habitat restoration, and
establishment of additional populations within their historical range.
The strategy uses strategic habitat conservation and adaptive
management principles, and will identify necessary permits and
compliance needs well in advance of the need for such authorization.
Each party seeks input and support from scientific and technical
support staff within their agencies or organizations for the entire
HMCG to consider for integration in overall planning, implementation,
analysis, and monitoring efforts collectively found to be necessary for
the conservation of coastal marten and its habitat. It is not the
intent of the conservation strategy to supplant any ongoing and planned
conservation efforts by the individual parties; instead, the
conservation strategy intends to identify opportunities to enhance
those conservation efforts. The HMCG holds quarterly meetings to
facilitate completion and implementation of the conservation strategy.
The California component of the conservation strategy is estimated to
be completed in the spring of 2015, followed by the Oregon component in
late 2015 or early 2016. A final conservation strategy for both states
(as a single coastal marten conservation strategy) is estimated to be
completed in 2016.
Tribes that own or manage lands within the historical range of the
coastal marten (and may or may not have currently suitable coastal
marten habitat on their lands) include: Coquille Indian Tribe;
Confederated Tribes of Grand Ronde Community of Oregon; Confederated
Tribes of Siletz Indians of Oregon (Siletz Indians); Hoopa Valley
Tribe, California; Yurok Tribe of the Yurok Reservation, California
(Yurok Tribe); Wiyot Tribe, California; Karuk Tribe; Elk Valley
Rancheria, California; Smith River Rancheria, California; Resighini
Rancheria, California; Big Lagoon Rancheria, California; Cher-Ae
Heights Indian Community of the Trinidad Rancheria, California; Blue
Lake Rancheria, California; Bear River Band of the Rohnerville
Rancheria, California; Cahto Tribe of the Laytonville Rancheria;
Sherwood Valley Rancheria of Pomo Indians of California; and Manchester
Band of Pomo Indians of the Manchester Rancheria, California.
Although suitable habitat for coastal martens may occur on tribal
lands, our records indicate that none of the tribes in coastal Oregon
or in coastal northern California specifically manage for coastal
marten populations or habitat on their lands. However, the Siletz
Indians manage 1,700 ha (4,300 ac) of forest land for the benefit of
marbled murrelets (Brachyramphus marmoratus) in Oregon, which
coincidentally may also provide suitable habitat for coastal martens,
and the Yurok Tribe is a member of the HMCG and currently owns
approximately 23 percent of the total area of the coastal northern
California population area, most of which is occupied by coastal
martens. The best available information does not identify what the
Yurok Tribe's vegetation management activities or potential impacts may
be to coastal martens and their habitat. However, we will continue to
work with the Yurok Tribe, including through the HMCG, and explore
potential coastal marten conservation actions on their lands. We also
anticipate coordinating with other tribes that may harbor suitable
coastal marten habitat within the range of the coastal marten.
In addition to conservation actions either planned or already being
implemented related to the HMCG and tribal efforts, the Green Diamond
Resource Company's (formerly Simpson Timber Company) 1992 Northern
Spotted Owl Habitat Conservation Plan (HCP) (Simpson Timber Company
1992, entire) covers lands that contain suitable habitat for coastal
marten. This HCP describes how Green Diamond Resource Company
identifies (during planning for timber harvest) ways to retain resource
attributes that provide core habitat for future northern spotted owl
habitat, including retention of: (1) Hardwood and conifer patches, (2)
habitat structure along watercourses, (3) hard and soft snags, (4)
standing live culls (i.e., trees of marketable size that are useless
for all but firewood or pulpwood because of crookedness, rot, injuries,
or damage from disease or insects), and (5) small areas of undisturbed
brush (Simpson Timber Company 1992, entire). These HCP goals
coincidentally will provide a
[[Page 18767]]
benefit to coastal martens that may occur on those lands. However, we
note that the level and extent of resource retention are not defined,
and the current description to retain ``small areas of undisturbed
brush'' is helpful, but not necessarily adequate for the needs of the
coastal marten (i.e., management relies primarily on clear cut
management of timberlands). The Green Diamond Resource Company is in
the initial stages of developing a new HCP for their lands, although
currently the coastal marten is not a covered species. Because 11
percent of the coastal northern California extant population area is on
Green Diamond Resource Company timberlands, we are currently working
with them to incorporate conservation actions into the HCP that would
benefit the coastal marten and its habitat, particularly in those areas
that lie between large suitable tracks of public lands.
Finding
As required by the Act, we considered the five factors in assessing
whether the coastal marten is an endangered or threatened species
throughout all of its range. We examined the best scientific and
commercial data available regarding the past, present, and future
stressors faced by the coastal marten. We reviewed the petition,
information available in our files, and other available published and
unpublished information, and we consulted with recognized marten and
habitat experts, and other Federal, State, and tribal agencies. Listing
is warranted if, based on our review of the best available scientific
and commercial data, we find that the stressors to the coastal DPS of
the Pacific marten are so severe or broad in scope as to indicate that
the coastal marten is in danger of extinction (endangered), or likely
to become endangered within the foreseeable future (threatened),
throughout all or a significant portion of its range.
For the purposes of this evaluation, we are required to consider
potential impacts to coastal martens into the foreseeable future. Based
on the best available scientific and commercial information and to
provide the necessary temporal context for assessing stressors to
coastal martens, we determined 15 years (i.e., 3 marten generations) to
be the foreseeable future for consideration of most of the stressors to
coastal marten, as this period allows for analysis of multiple
generations of coastal martens over a reasonable time period, as
opposed to examining further into the future where assumptions or
extensive uncertainty would not allow meaningful predictions of
potential future impacts. For two stressors, we have defined different
periods: 30 years constitutes the foreseeable future over which we
assessed the stressor of wildfire (based on the expected future
equivalent level of fire frequency, size, and severity as compared to
the past 30 years), and 40-50 years constitutes the foreseeable future
over which we assessed the stressor of climate change (based on model
projections of climate changes for coastal Oregon and coastal northern
California).
We evaluated each of the potential stressors in the Species Report
(Service 2015, entire) for the coastal DPS of Pacific marten, and we
determined that wildfire (Factor A), habitat impacts due to the effects
of climate change (Factor A), vegetation management (Factor A),
development (Factor A), trapping (for fur and research purposes)
(Factor B), disease (Factor C), predation (Factor C), collision with
vehicles (Factor E), exposure to toxicants (Factor E), and small and
isolated population size effects (Factor E) are factors that have
either minimally impacted individuals in one or more of the populations
or that may potentially have impacts on individuals or populations in
the future. Our analysis resulted in the following conclusions for each
of the stressors:
Wildfire impacts are likely to occur throughout the range
of the coastal marten similar to the historical impacts that have
occurred based on the impact level estimates of the prevalence of
wildfires within each extant population area between 1984-2012 (roughly
30 years). Overall, these impacts do not rise to the level of a threat
based on the continued persistence of moderate- and high-quality
habitat following past fires, the continued presence of relatively
moist habitat conditions (overall) that moderate the dry conditions
that promote fire ignition and spread, and little effect of altered
structure or composition of the dominant forest types in areas that
have experienced fire suppression. Thus, we do not anticipate a
significant reduction in suitable habitat for coastal martens as the
result of wildfire.
Climate change modeling predicts a range of potential
effects on vegetation, including some that indicate conditions could
remain suitable for coastal martens in portions of the coastal range.
The severity of potential impacts to coastal marten habitat will likely
vary across the range, with effects to coastal martens potentially
ranging from negative to neutral or potentially beneficial. Although
many climate models generally agree about the changes in temperature
and precipitation, the consequent effects on vegetation are more
uncertain, as is the rate at which any such changes might be realized.
Therefore, it is not clear how or when changes in forest type and plant
species composition will affect the distribution of coastal marten
habitat. There is additional uncertainty as to fine-scale features of
suitable marten habitat that may be affected by climate change, whether
any changes will occur at a scale relevant to the taxon, and how these
changes will be expressed in the coastal marten populations. Overall,
we lack sufficient information to predict with any certainty the future
direct impacts of climate change on coastal marten habitat or
populations. Consequently, we have determined that we do not have
reliable information to suggest that climate change is a threat to
coastal marten habitat now or in the future, although we will continue
to seek additional information concerning how climate change may affect
coastal marten habitat.
Vegetation management is likely to have an overall low
impact on the loss, degradation, or fragmentation of suitable coastal
marten habitat across the range of the DPS both currently and into the
future. Some loss of suitable habitat (primarily low-quality suitable
habitat) is expected to continue to occur into the future on private
lands within all three population areas. However, private lands support
a relatively small proportion of the suitable habitat available for
coastal martens within extant population areas. Federal lands
constitute a majority of the extant population areas, have longer
timber-harvest rotations, and retain more structural features on the
subset of that area in matrix lands. In addition, most of the Federal
lands that provide suitable habitat are in Federal Reserves, which are
managed for the maintenance and recruitment of late-successional
habitat characteristics beneficial for coastal martens; suitable
habitat is thus expected to increase in Federal Reserves. Therefore,
overall potential impacts from vegetation management do not rise to the
level of a threat.
Development has an overall low impact on the loss,
degradation, or fragmentation of suitable coastal marten habitat across
the range of the DPS both currently and into the future, and thus does
not rise to the level of a threat. If development does occur, loss of
suitable habitat is expected to be minimal, as has been the trend over
the past 30 years.
Fur trapping of coastal martens has no impact to the
population in coastal northern California because trapping for martens
is illegal in California. Possible illegal fur trapping in California,
as well as rangewide potential impacts
[[Page 18768]]
associated with livetrapping for research purposes or incidental
trapping of martens (when intentionally trapping for other furbearer
species) is not expected to result in population-level impacts. Some
martens could be trapped in Oregon where fur trapping for martens is
legal, although we estimate that potential impacts will not be
significant at the population- or rangewide level based on the best
available trapping data for Oregon. Additionally, potential impacts
from live-trapping and handling for research purposes on coastal marten
populations is discountable. Thus, impacts from fur trapping and
trapping for research purposes across the coastal marten's range do not
rise to the level of a threat.
Disease has not been documented in the past within coastal
marten populations. The prevalence of possible past exposure to lethal
pathogens within the coastal northern California population and the
coastal Oregon populations has not been determined, and we have no
information to suggest that disease is currently present in any of the
populations. At this point in time, there is a low probability that a
disease outbreak may occur. We anticipate that if there should be an
outbreak, it would likely have a low impact on all three coastal marten
populations combined since the distance between the extant populations
makes it unlikely that an outbreak would spread to all three
populations. Thus, disease does not rise to the level of a threat.
Predation is a natural process and is generally only
considered a threat if it is occurring at unnaturally high levels that
are not sustainable. The population-level impact of predation within
the three coastal marten extant population areas is currently unknown,
although the best available data from one evaluation of predation
indicate a 33 percent annual predation rate for the coastal northern
California population (Slauson et al. 2014, unpubl. data). This level
of predation is expected to be sustainable when compared with the
observed annual juvenile coastal marten survival rate of 50 percent,
and thus predation alone would not likely result in a population-level
impact. Therefore, based on the best available data at this time, we
have determined that predation does not rise to the level of a threat
given that it is a natural phenomenon that appears to be occurring at a
sustainable level.
Collisions with vehicles are rare, but they can be
expected into the future. Known rates of mortality due to collisions
with vehicles have been low for coastal martens, and the best available
information does not suggest any significant increases in vehicular
traffic or new highways to be built in areas where martens occur.
Therefore, it is reasonable to expect the impact of collisions with
vehicles on coastal martens to continue at similar levels into the
future and not rise to the level of a threat.
Illegal and legal marijuana cultivation sites (and use of
ARs and other pesticides) are present within or near all three coastal
marten populations, although the probability of exposure varies between
them. The degree of exposure and the effect of such exposure on coastal
martens, should it occur, is unknown and thus far unstudied. There is
significant uncertainty as to the severity of impact that this stressor
may have on coastal martens at the population- and rangewide levels
given that the best available data are minimal regarding this stressor
and coastal martens at this time, and given the lack of information
regarding potential sublethal effects. Furthermore, it is unclear how
the recent legalization of marijuana in Oregon will affect the amount
or spread of illegal marijuana grow sites. The best available
information does not suggest that these potential impacts rise to the
level of a threat, primarily based on the available information on
levels of known marten exposure to ARs and lack of evidence that ARs
are having a population-level effect.
Small, isolated populations are more susceptible to
impacts, and therefore, we evaluated whether coastal marten populations
are small and isolated such that these negative effects are likely to
be realized. At this time, evidence suggests that coastal marten
distribution has contracted markedly in California and southern Oregon
since the early 20th century. Although the coastal northern California
population abundance declined in the recent past (based on survey data
between 2000 and 2008 (Slauson et al. 2009b, p. 10)), the population
abundance since that time appears to have remained unchanged as
indicated by the most recent preliminary abundance estimates available
from 2012. The abundance and trend of coastal marten populations in
coastal Oregon is unknown, although recent surveys in some areas of
coastal Oregon (which are not yet complete) are documenting the
presence of martens as anticipated. Although the known populations are
disjunct, the dispersal capabilities of martens and habitat modeling
suggest the potential for interchange of individuals between the
populations. In addition, martens may occur between or adjacent to the
known populations in areas where surveys have been limited or absent.
The best available data at this time indicate that although coastal
martens are likely reduced in abundance or distribution relative to
their historical numbers and range, there is no empirical evidence that
any current populations of coastal marten are in decline. Thus, small
or isolated population size effects do not rise to the level of a
threat either currently or in the foreseeable future.
Potential cumulative impacts to the coastal marten from
all stressors combined or some of the stressors are possible; however,
the most likely scenarios for cumulative impacts are likely to only
occur from the following three scenarios: Increased frequency or size
of wildfires associated with potential climate changes; increased
coastal marten mortality rates from predation, disease, or other
factors following a sublethal exposure to toxicants; or possible
increased coastal marten predation rates due to decreased shrub
densities resulting from vegetation management activities. Based on the
best available data at this time and as described above, none of these
possible cumulative impacts are likely to occur currently or into the
foreseeable future to such a degree that the effects are expected to
lead to population- or rangewide-level declines. Therefore, the
cumulative impact of these potential stressors does not rise to the
level of a threat.
We also evaluated existing regulatory mechanisms (Factor D) and did
not determine an inadequacy of existing regulatory mechanisms for
coastal marten. Specifically, we found that multiple Federal land use
plans (e.g., LRMPs, NWFP) or State regulations (e.g., Oregon forest
practice rules) are being implemented, often providing broad latitude
for land managers, but with explicit sideboards for directing
management activities. We also note that significant Federal efforts
have been developed and are being implemented (e.g., NWFP) to abate the
large-scale loss of forested habitat-types deemed essential for coastal
martens. Additional efforts are also underway within the reserve areas
that constitute a majority of the Federal lands in areas occupied by
coastal martens to promote further recruitment of such habitat.
None of these impacts, as summarized above, was found to
individually or cumulatively impact the coastal DPS of Pacific marten
to a degree such that listing is warranted at this time. Based on the
analysis contained within the Species Report (Service 2015, pp. 41-95),
we conclude that the best available scientific and commercial
information indicates that these stressors are not
[[Page 18769]]
singly or cumulatively causing a decline of the DPS or its habitat
currently, nor are the stressors likely to be significant in the
foreseeable future to the degree that they would result in declines of
one or more populations such that the DPS would be in danger of
extinction, or likely to become so within the foreseeable future.
We base our decision on the following:
(1) Although habitat-based impacts may be occurring currently or in
the future primarily as a result of wildfire and vegetation management
(and, to an unknown degree, the effects of climate change), much of the
coastal marten's habitat is not in especially fire-prone forest types,
and vegetation management has significant impacts only on the
relatively small area in private ownership within its range.
Significant amounts of moderate- and high-suitability habitat are
currently available on Federal and State lands within all three
population areas, including approximately 44 percent of the coastal
central Oregon population area, 70 percent of the coastal southern
Oregon population area, and 63 percent of the coastal northern
California population. Moderate- and high-suitability habitat in the
coastal central Oregon population area is a currently undetermined
value greater than 44 percent because the habitat suitability model did
not account for occupied coastal dune habitat that exists as a narrow
coastal strip along the western boundary of that population area.
Overall, the existing moderate- and high-suitability habitat includes
some areas that appear to be either (or both): (a) Resilient to many
high-severity fires due to pronounced levels of precipitation and cool,
moist summer conditions that exist along the coast currently and into
the future; and (b) protected from significantly damaging treatments of
vegetation management (i.e., State and Federal lands such as those
being managed under the NWFP, National Park Service lands, and lands
managed by the Oregon and California Department of Parks and
Recreation), including 77 percent of the moderate- and high-suitability
habitat in the coastal central Oregon population area, 90 percent of
the moderate- and high-suitability habitat in the coastal southern
Oregon population area, and 78 percent of the moderate- and high-
suitability habitat in the coastal northern California population area.
(2) Coastal marten populations throughout their range have likely
experienced declines or significant impacts in the past (i.e.,
harvesting and trapping for fur), which undoubtedly influenced the
current distribution of these populations. The population size of
coastal martens in the coastal northern California population area is
estimated to be fewer than 100, but is no longer in decline as shown by
survey data available from 2000, 2008, and preliminary abundance
estimates from 2012. The abundance and distribution of coastal martens
in coastal Oregon is unknown, coastal northern Oregon is unsurveyed,
and there are no data available on which to estimate any trend in known
populations in coastal central and coastal southern Oregon. We presume
that coastal marten populations may not be especially large or
expansive, given the historical impacts of overtrapping and timber
harvest. However, these past threats have been largely ameliorated, and
we have no evidence to suggest that current stressors are resulting in
any population declines, such that we would consider the DPS of coastal
marten to be on a trajectory toward extinction. We thoroughly evaluated
impacts to the DPS and its habitat with regard to the five listing
factors. Similar to the stressors described in (1) above for potential
impacts to habitat, we found minimal evidence of population-level
impacts.
We recognize a need to continue to monitor the coastal marten
because the populations are disjunct, which in general makes them more
susceptible to stressors than species with larger, more well-connected
populations. There has been relatively little survey effort throughout
much of the range of the DPS, however. In general, the interchange of
only a few individuals is needed to maintain genetic connectivity
between populations over time. As described in this document and the
Species Report (Service 2015, entire), there are stressors that we find
may be having some effect on coastal marten populations, albeit not to
the degree that they currently rise to the level that listing is
warranted. We will continue to monitor the status of the DPS and
evaluate any other information we receive. Additional information will
continue to be accepted on all aspects of the DPS. If at any time data
indicate that protective status under the Act should be provided or if
there are new threats or increasing stressors that rise to the level of
a threat, we can initiate listing procedures, including, if
appropriate, emergency listing pursuant to section 4(b)(7) of the Act.
In conclusion, we acknowledge that the coastal marten population in
California may be reduced in size relative to its historical abundance,
and that coastal martens may be reduced in distribution as compared to
their historical range. A listing determination, however, must be based
on our assessment of the current status of the species--in this case,
the coastal DPS of the Pacific marten--in relation to the five listing
factors under the Act. Section 4 of the Act requires that we make such
a determination based solely on the best scientific and commercial data
available. To this end, we must rely on reasonable conclusions as
supported by the best available science to assess the current and
future status to determine whether the coastal marten meets the
definition of an endangered or threatened species under the Act. Based
on our review of the best available scientific and commercial
information pertaining to the five factors, we find that the stressors
acting upon the coastal DPS of the Pacific marten are not of sufficient
imminence, intensity, or magnitude to indicate that the coastal marten
is in danger of extinction now (endangered), or likely to become
endangered within the foreseeable future (threatened), throughout all
of its range.
Significant Portion of the Range
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 [DPS] of any species of vertebrate fish or wildlife which
interbreeds when mature.'' We published a final policy interpreting the
phrase ``Significant Portion of its Range'' (SPR) (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
[[Page 18770]]
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 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 (``species'' under the Act refers to any listable
entity, including species, subspecies, or DPS) 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 is 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
endangered or threatened. 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. We emphasize that
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.''
We consider the historical range of the coastal marten to include
coastal Oregon from the Columbia River (Clatsop and Columbia counties)
south into northern Sonoma County, California, including suitable
habitat from the coast eastward to an elevation of 1,524 m (5,000 ft).
This range encompasses the coastal central Oregon extant population
area, the coastal southern Oregon extant population area, the coastal
northern California extant population area, and the intervening
habitat. Based on the best available information at this time, these
populations account for the current distribution of the DPS.
In considering any significant portion of the coastal marten's
range, we considered whether the stressors facing the coastal marten
might be different at three locations where the coastal martens have
been found and, thus, geographically concentrated in some portion of
the range of the DPS. In the Summary of Information Pertaining to the
Five Factors analysis above, we identified the most likely potential
differences associated with fur trapping in Oregon, wildfire, climate
change, development and vegetation management (timber harvesting), and
toxicant exposure.
(1) Fur trapping is legal in Oregon, and thus the two Oregon
populations may be affected by this activity. Population-level impacts
of legal coastal marten fur trapping within the two Oregon extant
population areas have not been studied, as the impact of trapping on a
marten population requires an estimate of population abundance, which
is currently unavailable for both extant population areas in coastal
Oregon. Based on the very few individuals removed from this population
over time (36 individuals harvested from trapping over a 26-year
period, between 1969 and 1995--on average fewer than 2 per year), the
best available data indicate that fur trapping is unlikely to result in
population-level impacts.
Fur trapping of martens is illegal in California but legal for
other furbearer species. We expect that nearly all coastal martens that
are accidentally captured in box traps set for other furbearer species
(or that are live-trapped for research purposes) are released unharmed.
Although illegal fur trapping specifically for martens is also a
possibility in California, the best available data at this time do not
indicate that illegal fur trapping or incidental legal live-trapping
for coastal martens for research purposes is resulting in population-
level impacts. Overall, we do not find that the potential impacts from
fur trapping (illegal or legal) and live-trapping for research purposes
are geographically concentrated in any one portion of the range of the
DPS.
(2) The potential impacts from wildfire are slightly greater within
the coastal southern Oregon and coastal northern California populations
as compared to the coastal central Oregon population when considering
historical (between 1984 and 2012) wildfire incidents and the
likelihood that into the foreseeable future (approximately 30 years),
the frequency, intensity, and severity of wildfires are expected to be
similar to the recent past. However, these wildfires in coastal
southern Oregon and coastal northern California have burned at varying
levels of severity and have thus only partially impacted (i.e., not
completely removed) suitable habitat and the adjacent, intervening
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suitable habitat that the coastal marten would need to rely on during
post-fire habitat recovery periods. Surveys of these areas (including
the drier, inland, xeric areas) post-burn indicate that low-, moderate-
, and high-suitability habitat remain within and adjacent to these past
wildfire perimeters. Therefore, although future wildfires are expected
to occur similarly to those documented in the past 30 years throughout
the coastal marten's range (i.e., among all three extant population
areas), and given the potential for increased temperatures and
decreased precipitation over the next 50 years (see ``Climate Change''
under Factor A, above) throughout its entire range, we do not
anticipate a concentration of threats in any one portion of the DPS'
range due to:
(a) The coastal marten's range continuing to occur within a
(generally) fog-influenced coastal zone, and thus the continued
widespread presence of persistent, moist conditions year-round
(including Pacific storms in the winter and cloud cover or coastal fog
in the summer) that likely result in lower severity wildfires than what
would occur in areas without the a moist, coastal influence; and
(b) The anticipated widespread presence of varying levels of
suitable habitat post-fire throughout the coastal marten's range, as
demonstrated by post-burn surveys.
(3) The potential impacts from climate change are slightly greater
within the coastal southern Oregon and coastal northern California
populations, which models indicate could result in a warmer and drier
climate into the foreseeable future (40 to 50 years) as compared to the
coastal central Oregon population. Nearly all models that encompass the
landscape containing these two population areas show shifts in
vegetation type to habitat that may be considered less favorable for
coastal martens. However, most models project these shifts in
vegetation type over time by the end of the century, and the models
predict these same potential vegetation shifts in coastal central and
northern Oregon. Additionally, even if vegetation shifts occur,
suitable habitat for coastal martens is expected to remain in portions
of the coastal southern Oregon and coastal northern California
population areas, to which coastal martens could migrate (see Climate
Change, above). Overall, we do not anticipate a geographic
concentration of threats in any one portion of the DPS' range given the
variety of potential effects from climate change, the high level of
uncertainty regarding the nature and timing of any such effects, and
the likelihood that suitable habitat for coastal martens will remain
available into the foreseeable future throughout the entire range of
the DPS despite potential climate change impacts.
(4) Both development (e.g., road building, dam construction and
creation of new reservoirs, conversion of forest habitat for
agricultural use, development and expansion of recreational areas) and
vegetation management (e.g., timber harvest, thinning, fuels reduction)
are expected to continue on some private lands throughout the range of
the coastal marten. These activities potentially may occur to a greater
extent in the coastal central Oregon population area as compared to the
coastal southern Oregon and coastal northern California population
areas due to the greater percentage of moderate- and high-suitability
marten habitat in private ownership in the coastal central Oregon
population area (i.e., 23 percent as opposed to 10 percent and 11
percent, respectively). However, the best available data do not
indicate that either potential development activities or vegetation
management in one or more of these population areas will occur at a
level greater than any other (i.e., the potential impacts are uniformly
distributed throughout the DPS's range). Additionally, the best
available data do not indicate that any new development or vegetation
management activities (i.e., those that would remove currently suitable
habitat) would occur into the foreseeable future to such a degree that
population-level impacts are likely. We have made this conclusion
primarily based on the extensive amount of Federal lands both within
and adjacent to all three populations where overall beneficial
vegetation management (such as that outlined in the NWFP) would occur,
thus providing an overall conservation benefit to coastal marten
rangewide.
Some vegetation management activities may also occur throughout the
coastal marten's range that may result in short-term impacts to coastal
marten (such as thinning, fuels reduction projects, and habitat
restoration), but eventually result in long-term benefits to coastal
martens and their habitat. In these cases, the long-term benefits
likely outweigh the potential short-term, localized impacts by
improving habitat suitability for the coastal marten in the long-term
through: (a) Minimizing loss of late-successional stands due to
wildfires, and (b) accelerating the development of late-seral
characteristics. Although short-term degradation of suitable habitat
could occur, these types of projects are designed to ultimately
increase the overall amount, distribution, and patch size of suitable
coastal marten habitat.
(5) Potential exposure of coastal martens to toxicants as a result
of illegal marijuana cultivation sites is likely to continue on some
lands within the coastal marten's range. This type of activity could
potentially occur in those areas where marijuana grow sites are located
(which currently is known to be a fraction of the coastal marten's
range). Based on the presence of suitable climate conditions for
marijuana cultivation and data that indicate a greater concentration of
recently eradicated cultivation sites within or near the coastal
northern California population area, these activities may possibly
occur to a greater extent in the coastal northern California population
area as compared to the coastal Oregon population areas. Of note is
that incidence of toxicant exposure and the potential population-level
effects to coastal marten are largely unknown, and there is significant
uncertainty as to the severity of impact (both lethal and sublethal)
that this stressor may have at the population- and rangewide levels on
coastal marten, especially given the recent legalization of marijuana
in Oregon (note that marijuana is not legal in California). The best
available data indicate broad use of ARs at illegal marijuana
cultivation sites, as well as continued use of ARs at legal grow sites,
both of which are found within the range of the DPS, but the degree of
exposure that may result for coastal martens is unknown. To date, only
one record of a positive exposure exists within the range of the
coastal marten that demonstrates exposure to ARs. Therefore, at this
time, the best available data do not indicate that the coastal marten's
exposure to ARs will occur at a level greater than any other in any one
portion of the range of the DPS.
In summary, our evaluation of the best available information
indicates that the overall level of stressors is not geographically
concentrated in one portion of the coastal marten's range, and that the
stressors that have the potential to impact coastal martens are
relatively consistent across its range (Service 2015, entire).
Therefore, it is our conclusion, based on our evaluation of the current
potential threats to the coastal marten (see Summary of Information
Pertaining to the Five Factors section of this finding and the
``Stressors on Coastal Marten Populations and Habitat'' section of the
Species Report (Service 2015, pp. 41-95)), that no portion of the range
of the coastal DPS of Pacific marten warrants
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further consideration of possible endangered or threatened status under
the Act.
Our review of the best available scientific and commercial
information indicates that the coastal marten is not in danger of
extinction (endangered) nor likely to become endangered within the
foreseeable future (threatened), throughout all or a significant
portion of its range. Therefore, we find that listing the coastal DPS
of the Pacific marten as an endangered or threatened species under the
Act is not warranted at this time.
We request that you submit any new information concerning the
status of, or threats to, the coastal marten to our Arcata Fish and
Wildlife Office (see ADDRESSES) whenever it becomes available. New
information will help us monitor coastal martens and encourage their
conservation. If an emergency situation develops for the coastal
marten, we will act to provide immediate protection.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Arcata Fish and
Wildlife Office (see ADDRESSES).
Authors
The primary authors of this document are the staff members of the
Pacific 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: March 30, 2015.
Robert Dreher,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2015-07766 Filed 4-6-15; 8:45 am]
BILLING CODE 4310-55-P