Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Humboldt Marten as Endangered or Threatened, 1900-1908 [2012-479]
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Federal Register / Vol. 77, No. 8 / Thursday, January 12, 2012 / Proposed Rules
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[FR Doc. 2012–447 Filed 1–11–12; 8:45 am]
BILLING CODE 6560–50–P
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; 90-Day Finding on a
Petition To List the Humboldt Marten
as Endangered or Threatened
Fish and Wildlife Service,
Interior.
ACTION: Notice of petition finding and
initiation of status review.
AGENCY:
We, the U.S. Fish and
Wildlife Service (Service), announce a
90-day finding on a petition to list the
Humboldt marten (Martes americana
humboldtensis) as endangered or
threatened and designate critical habitat
under the Endangered Species Act of
1973, as amended (Act). Based on our
review, we find that the petition
presents substantial scientific or
commercial information indicating that
listing the Humboldt marten may be
warranted. Therefore, with the
publication of this notice, we are
initiating a review of the status of the
Humboldt marten to determine if listing
is warranted. To ensure that this status
review is comprehensive, we are
SUMMARY:
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requesting scientific and commercial
data and other information regarding the
Humboldt marten. Based on the status
review, we will issue a 12-month
finding on the petition, which will
address whether the petitioned action is
warranted, as provided in section
4(b)(3)(B) of the Act.
DATES: To allow us adequate time to
conduct this review, we request that we
receive information on or before March
12, 2012. The deadline for submitting an
electronic comment using the Federal
eRulemaking Portal (see ADDRESSES
section, below) is 11:59 p.m. Eastern
Time on this date. After March 12, 2012,
you must submit information directly to
the Field Office (see FOR FURTHER
INFORMATION CONTACT section below).
Please note that we might not be able to
address or incorporate information that
we receive after the above requested
date.
ADDRESSES: You may submit
information by one of the following
methods:
(1) Electronically: Go to the Federal
eRulemaking Portal: https://
www.regulations.gov. In the Enter
Keyword or ID box, enter Docket No.
FWS–R8–ES–2011–0105, which is the
docket number for this action. Then
click on the Search button. You may
submit a comment by clicking on ‘‘Send
a Comment or Submission.’’
(2) By hard copy: Submit by U.S. mail
or hand-delivery to: Public Comments
Processing, Attn: FWS–R8–ES–2011–
0105; Division of Policy and Directives
Management; U.S. Fish and Wildlife
Service; 4401 N. Fairfax Drive, MS
2042–PDM; Arlington, VA 22203.
We will post all information we
receive on https://www.regulations.gov.
This generally means that we will post
any personal identifying information
you provide us (see the Request for
Information section below for more
details).
FOR FURTHER INFORMATION CONTACT:
Nancy J. Finley, Field Supervisor; by
mail at Arcata Fish and Wildlife Office,
1655 Heindon Road, Arcata, CA 95521;
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:
Request for Information
When we make a finding that a
petition presents substantial
information indicating that listing a
species may be warranted, we are
required to promptly review the status
of the species (status review). For the
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status review to be complete and based
on the best available scientific and
commercial information, we request
information on the Humboldt marten
from governmental agencies, Native
American tribes, the scientific
community, industry, and any other
interested parties. We seek information
on:
(1) The Humboldt marten’s biology,
range, and population trends, including:
(a) Habitat requirements for feeding,
breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range,
including distribution patterns;
(d) Historical and current population
levels, and current and projected trends;
and
(e) Past and ongoing conservation
measures for the Humboldt marten, its
habitat, or both.
(2) The factors that are the basis for
making a listing determination for a
species under section 4(a) of the Act
(16 U.S.C. 1531 et seq.), which are:
(a) The present or threatened
destruction, modification, or
curtailment of Humboldt marten habitat
or its 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.
If, after the status review, we
determine that listing the Humboldt
marten is warranted, we will propose
critical habitat (see definition in section
3(5)(A) of the Act) under section 4 of the
Act, to the maximum extent prudent
and determinable at the time we
propose to list the species. Therefore,
we also request data and information
on:
(1) What may constitute ‘‘physical or
biological features essential to the
conservation of the species,’’ within the
geographical range currently occupied
by the species;
(2) Where these features are currently
found;
(3) Whether any of these features may
require special management
considerations or protection;
(4) Specific areas outside the
geographical area occupied by the
species that are ‘‘essential for the
conservation of the species;’’and
(5) What, if any, critical habitat you
think we should propose for designation
if the species is proposed for listing, and
why such habitat meets the
requirements of section 4 of the Act.
Please include sufficient information
with your submission (such as scientific
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journal articles or other publications) to
allow us to verify any scientific or
commercial information you include.
Submissions merely stating support
for or opposition to the action under
consideration without providing
supporting information, although noted,
will not be considered to provide the
best information to support a
determination. Section 4(b)(1)(A) of the
Act directs that determinations as to
whether any species is an endangered or
threatened species must be made
‘‘solely on the basis of the best scientific
and commercial data available.’’
You may submit your information
concerning this status review by one of
the methods listed in the ADDRESSES
section. If you submit information via
https://www.regulations.gov, your entire
submission—including any personal
identifying information—will be posted
on the Web site. If your submission is
made via a hardcopy that includes
personal identifying information, you
may request at the top of your document
that we withhold this personal
identifying information from public
review. However, we cannot guarantee
that we will be able to do so. We will
post all hardcopy submissions on
https://www.regulations.gov.
Information and supporting
documentation that we received and
used in preparing this finding is
available for you to review at https://
www.regulations.gov, or by
appointment, during normal business
hours, at the U.S. Fish and Wildlife
Service, Arcata Fish and Wildlife Office
(see FOR FURTHER INFORMATION CONTACT
section, above).
Background
Section 4(b)(3)(A) of the Act requires
that we make a finding on whether a
petition to list, delist, or reclassify a
species presents substantial scientific or
commercial information indicating that
the petitioned action may be warranted.
We are to base this finding on
information provided in the petition,
supporting information submitted with
the petition, and information otherwise
available in our files. To the maximum
extent practicable, we are to make this
finding within 90 days of our receipt of
the petition and publish our notice of
the finding promptly in the Federal
Register.
Our standard for substantial scientific
or commercial information within the
Code of Federal Regulations (CFR) with
regard to a 90-day petition finding is
‘‘that amount of information that would
lead a reasonable person to believe that
the measure proposed in the petition
may be warranted’’ (50 CFR 424.14(b)).
If we find that substantial scientific or
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commercial information was presented,
we are required to promptly conduct a
species status review, which we
subsequently summarize in our
12-month finding.
Petition History
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 the Humboldt marten (Martes
americana humboldtensis), a subspecies
of the American marten, be listed as
endangered or threatened and that
critical habitat be designated in
accordance with the Act. The document
received clearly identified itself as a
petition and included the requisite
identification information for the
petitioners, as required by 50 CFR
424.14(a). 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. This finding
addresses the petition.
Listable Entity Evaluation
Under section 3(16) of the Act, we
may consider for listing any species or
subspecies of fish, wildlife, or plants, or
any distinct population segment of
vertebrate fish or wildlife which
interbreeds when mature. Such entities
are considered eligible for listing under
the Act (and are, therefore, referred to as
‘‘listable entities’’) should they be
determined to meet the definition of an
endangered or threatened species. The
petition states that genetics research
indicates that the currently recognized
species American marten (Martes
americana) should be divided into two
species—M. americana and M. caurina
(CBD and EPIC 2010, p. 6). The petition
indicates that if marten taxonomy is
changed in the near future, the currently
recognized subspecies Humboldt marten
(M. americana humboldtensis) would
likely be designated a subspecies of the
newly designated species, M. caurina,
and thus would likely be renamed M.
caurina humboldtensis. Therefore, the
petition requested listing as endangered
or threatened one of the following: (1)
The currently recognized Humboldt
marten subspecies, M. americana
humboldtensis; or (2) the Humboldt
marten subspecies that may be
redesignated as M. caurina
humboldtensis; or (3) the Humboldt
marten as a distinct population segment
(DPS) of M. caurina (CBD and EPIC
2010, pp. 2, 6).
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Historically, marten populations in
coastal Oregon have not been included
within the range of the Humboldt
marten (see Taxonomy and Distribution
section, below). The petition indicates,
however, that because recent genetics
research indicates that populations of
American martens in coastal Oregon
(currently Martes americana caurina)
are more closely related to Martes
americana humboldtensis in coastal
northern California than to Martes
americana caurina populations in the
Cascade Range of Oregon (Slauson et al.
2009a, pp. 1339–1340), the petitioned
and listable entity should include all
marten populations in coastal northern
California and coastal Oregon (CBD and
EPIC 2010, pp. 7–10).
The standard of review for a 90-day
petition finding is ‘‘that amount of
information that would lead a
reasonable person to believe that the
measure proposed in the petition may
be warranted.’’ We determine that the
petition has met the threshold for
review in its characterization of
currently designated American marten
(M. americana) populations in coastal
northern California and coastal Oregon
as a potential listable entity. In our
status review, we will thoroughly
review all information relevant to the
taxonomic status of Humboldt martens.
For the purposes of this 90-day finding,
the common name Humboldt marten
refers to currently described American
marten (M. americana) populations in
coastal northern California and coastal
Oregon, based on the rationale provided
in the petition (CBD and EPIC 2010, pp.
2, 6–8, 10) and research by Slauson et
al. (2009a, pp. 1339–1340).
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Species Information
Taxonomy and Distribution
The Humboldt marten (Martes
americana humboldtensis) is a
subspecies of the American marten and
was first described by Grinnell and
Dixon (1926, p. 411). The Humboldt
marten is classified in the mammalian
order Carnivora, family Mustelidae
(weasels, otters, badgers), and subfamily
Mustelinae (martens, fisher, wolverine,
weasels). Clarke et al. (1987, p. 1)
recognized eight subspecies of the
American marten; Wilson and Reeder
(2005, p. 608) recognized 12 subspecies;
and Hall and Kelson (1959, p. 900) and
Hall (1981, pp. 981–985) recognized 14
subspecies. Differences between the
subspecies are based on morphological
and pelage characteristics (Hall and
Kelson 1959, p. 900; Hall 1981, pp. 983–
984) or cranial characters and fossil
history (Clarke et al. 1987, p. 1). The
Humboldt marten is recognized as a
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distinct subspecies of the American
marten by all of the aforementioned
authors.
The American marten occurs
throughout northern North America,
reaching its southjrnmost extent in the
Sierra Nevada of California and the
southern Rocky Mountains of New
Mexico (Gibilisco 1994, p. 66). The
historical range of the Humboldt marten
is based on the catch of licensed
trappers in California for the 5-year
period 1919–1924 (Grinnell and Dixon
1926, p. 415), and includes coastal
northern California, throughout the
coast redwood (Sequoia sempervirens)
zone from the Oregon border south to
Sonoma County (Grinnell and Dixon
1926, p. 415; Grinnell 1933, p. 100;
Grinnell et al. 1937, p. 209).
Historically, M. a. caurina has been
recognized to occur north of the coast
redwood zone in western Oregon,
Washington, and British Columbia
(Bailey 1936, p. 296; Hall 1981, p. 983;
Zielinski et al. 2001, p. 479).
In northwestern California, the
Klamath River separates the historical
range of the Humboldt marten from the
range of the Sierra Nevada marten (M.
a. sierrae), which occurs from the
Salmon-Trinity Mountains in interior
northwestern California, east to the
Cascades, and south throughout the
Sierra Nevada (Hall 1981, p. 983;
Zielinski et al. 2001, p. 479). Slauson
and Zielinski (2004, p. 62) suggest that
the xeric forest types in the river’s
canyon may act as a physical barrier
between these two subspecies.
In 2009, Slauson et al. (2009a, p.
1338) compared mitochondrial DNA
sequence diversity of martens from
extant marten populations within the
described ranges of M. a.
humboldtensis, M. a. caurina, and M. a.
sierrae, with a 1927 museum specimen
of M. a. humboldtensis. Martens from
coastal northern California share a
haplotype with the 1927 museum
specimen, supporting the hypothesis
that the existing population in coastal
northern California represents
descendants of the historical population
of Humboldt martens described by
Grinnell and Dixon in 1926 (Slauson et
al. 2009a, p. 1337). However, this same
haplotype also occurs in coastal Oregon
populations of M. a. caurina, but is
absent from the Oregon Cascades
population of M. a. caurina and from M.
a. sierrae, indicating that martens of
coastal Oregon are genetically more
similar to martens from coastal northern
California than they are to martens in
the Oregon Cascades (Slauson et al.
2009a, p. 1340). The results further
suggest that the historically defined
range boundary between M. a.
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humboldtensis and M. a. caurina at the
Oregon-California border may not be
valid, and that coastal Oregon martens
are part of the same taxonomic group as
Humboldt martens in coastal northern
California (Slauson et al. 2009a,
p. 1340). Slauson et al. (2009a, p. 1340)
concluded that, even though the coastal
northern California and coastal Oregon
marten populations share a common
haplotype, due to small sample sizes,
additional genetic analyses are
necessary to confirm the genetic
relationship. Slauson et al. (2009a,
p. 1337) noted that there are no known
contemporary or historical
biogeographic barriers to prevent northsouth movement of martens between
coastal northern California and coastal
Oregon. Therefore, a genetic
relationship between coastal marten
populations in northern California and
Oregon would not be unexpected. As
described above in Listable Entity
Evaluation, for the purposes of this
90-day finding, we conclude that
substantial information was provided in
the petition indicating that M.
americana populations in coastal
northern California and coastal Oregon
may constitute a valid listable entity.
We will evaluate all relevant
information on genetics and taxonomy
in our status review.
Population Status
Zielinski and Golightly (1996)
reviewed all published and unpublished
historical information on the Humboldt
marten, and the results of contemporary
(1989–1995) field surveys conducted
within its historical range, to determine
the status of the subspecies in the
redwood zone of California (redwoods
also occur in adjacent Curry County,
Oregon). They concluded that the
marten population in the northern Coast
Ranges of California significantly
declined during the 20th century and
that the last verifiable record was 50
years old, suggesting the subspecies was
very rare, if not extinct. However, in
1996 and 1997, martens were detected
at two survey stations in northwestern
California on the Six Rivers National
Forest (Zielinski et al. 1998, p. 1). These
1996–1997 presence-absence marten
surveys were conducted within
presumed suitable habitat, throughout
the historical range of the Humboldt
marten in northwestern California as
well as in extreme southern coastal
Oregon. Besides the marten detections
in northwestern California, martens
were also detected at survey stations
within 3 of the 19 sample units placed
in southern coastal Oregon (Zielinski et
al. 1998, p. 2). The southern-most
Oregon detection is over 50 miles (mi)
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(80 kilometers (km)) from the nearest
California detection. Much of the habitat
in this intervening area is suitable for
martens, but presumably unoccupied as
of the late 1990s.
The coastal northern California
marten population rediscovered in 1996
and 1997 is located in the north-central
portion of the described range for M. a.
humboldtensis (Grinnell and Dixon
1926, p. 413; Slauson et al. 2009a,
p. 1338). Based on results of a 2000–
2001 grid-based survey of the single
marten population rediscovered in
coastal northern California in 1996,
Slauson et al. (2009b, p. 13) concluded
that the entire Humboldt marten
population in California likely consists
of fewer than 100 individuals. The
Humboldt marten appears to have been
extirpated from greater than 95 percent
of the range it occupied in California in
the early 1900s (Grinnell et al. 1937, p.
209), with the single known extant
population occupying an estimated area
of only 170,000 acres (ac) (68,797
hectares (ha)) (Service 2010, p. 34).
Further, the Humboldt marten
population in California is estimated to
have undergone a 42 percent decline in
occupancy between grid-based surveys
conducted in 2000–2001 and 2008
(Slauson et al. 2009b, p. 10).
Martens in coastal Oregon are
currently known from only two disjunct
populations—one in central coastal
Oregon and one in southern coastal
Oregon—both of which are believed to
be in decline based mainly on a
reduction in the number of martens
trapped and anecdotal observations over
time (Zielinski et al. 2001, p. 478;
Slauson and Zielinski 2009, p. 36). No
systematic grid-based surveys have been
conducted on, nor population estimates
made for, the two populations of
martens in coastal Oregon. Concerns
about the viability of the two known
marten populations in coastal Oregon
have been expressed (Slauson et al.
2009a, p. 1340).
Published literature on the Humboldt
marten largely deals with distribution,
habitat selection, home range, diet, and
genetics. Little is known about
Humboldt marten reproductive biology,
demographics, disease, or predation.
Where data specific to the Humboldt
marten are lacking, we present
published information for other
American marten subspecies, with the
supposition that all subspecies of the
American marten share certain
characteristics and behaviors.
Biology
The American marten has a long,
slender body with relatively large
rounded ears, short limbs, and bushy
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tail (Clark et al. 1987, p. 1). American
martens have triangular faces with
muzzles less pointed than those of
foxes. The tail constitutes about onethird of the total body length (Powell et
al. 2003, p. 636). Each well-furred paw
includes five toes (Powell et al. 2003, p.
636). Total length of American martens
is between 19.7 and 26.8 inches (in) (50
and 68 centimeters (cm)) and adults
weigh 1.1 to 3.1 pounds (lb) (0.5 to 1.4
kilograms (kg)), depending on sex and
subspecies (Buskirk and McDonald
1989, p. 999); males are 20 to 40 percent
larger than females (Buskirk and
Zielinski 1997, p. 17). The color of the
long, silky, dense fur ranges from pale
yellowish buff to tawny brown to almost
black (Clark et al. 1987, p. 1). The color
of the head is usually lighter than the
body, and the legs and tail are darker
(Clark et al. 1987, p. 1).
Compared to the Sierra Nevada
marten, the other subspecies of
American marten that occurs in
California, the Humboldt marten is
reported to be darker, with a richer
golden tone, and to have less orange and
yellow in the throat patch, a smaller
skull (Grinnell and Dixon 1926, p. 411),
and smaller and less crowded premolars
and molars (Buskirk and Zielinski 1997,
p. 17). Grinnell et al. (1937, p. 207)
added that the Humboldt marten had
‘‘* * * far less orange-yellow color on
the throat and chest, and the usual area
of this color is much broken up by
coarse spots and marblings of body
brown.’’ Hagmeier (1961, p. 124)
describes the Humboldt marten as a
very small marten, perhaps the smallest
subspecies of American marten.
Sexual maturity for American martens
occurs by 1 year of age, but effective
breeding may not occur before 2 years
of age (Powell et al. 2003, p. 638).
Mating occurs in July or August and the
gestation period varies from 220 to 276
days (Strickland et al. 1982, p. 602).
Birth occurs in late March or April, due
to delayed implantation in which the
embryos remain in a state of arrested
development (Strickland et al. 1982, p.
602). Kits are completely dependent at
birth and weaned at about 42 days
(Buskirk and Ruggiero 1994, p. 17). The
male apparently takes no part in rearing
the young, which disperse in late
summer or autumn (Strickland et al.
1982, p. 603). American martens
produce an average of slightly less than
three young per female with one litter
per year (Strickland et al. 1982, p. 602).
For a mammal of their size, American
martens have relatively low
reproductive rates, but are long-lived
(up to 15 years in captivity and 14.5
years in the wild) (Strickland and
Douglas 1987, p. 535), suggesting a
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relatively slow potential recovery rate
from population-level impacts (Buskirk
and Ruggiero 1994, p. 16).
Slauson and Zielinski (2007a, p. 55)
characterized the diet of Humboldt
martens by scat analysis and found that
mammals (in 93 percent of scats) and
berries (in 85 percent of scats) were the
most frequently occurring items,
followed by birds (in 21 percent of
scats), insects (in 20 percent of scats),
and reptiles (in 7 percent of scats).
Sciurid rodents (especially Tamias
species (spp.)) and Murid voles
(Clethrionomys californicus and
Arborimus spp.) were the most common
mammal species found in Humboldt
marten scats (Slauson and Zielinski
2007a, p. 55). The frequency of berries
in the diet of the Humboldt marten was
the highest reported in diet studies of
the American marten; the frequency of
birds was also among the highest
reported (Slauson and Zielinski 2007a,
p. 55).
Strickland et al. (1982, p. 607)
summarized reports of American
martens being preyed upon by coyotes
(Canis latrans), fishers (Martes
pennanti), red foxes (Vulpes vulpes),
cougars (Puma concolor), eagles (Aquila
chrysaetos and Haliaeetus
leucocephalus), and great horned owls
(Bubo virginianus). Bull and Heater
(2001, p. 3), in their northeastern
Oregon study area, documented 18
American martens killed by predators: 8
by bobcats (Lynx rufus), 4 by raptors, 4
by other American martens, and 2 by
coyotes.
Slauson and Zielinski (2006, p. 65)
estimated seasonal (summer–fall) home
range size for Humboldt martens in
California using the 100 percent
minimum convex polygon method (a
polygon created by drawing a line
connecting the outer locations). Adult
male home ranges averaged 1,322 ac
(535 ha); the home range for a single
adult female with one kit was 315 ac
(127 ha). Juvenile female home ranges
averaged 1,491 ac (603 ha); the single
juvenile male home range was 453 ac
(183 ha).
Habitat
Historical records of the distribution
of Humboldt martens in California
suggest that the subspecies was closely
tied to coastal old-growth redwood
forests (Slauson et al. 2003, p. 3).
However, the one known remnant
Humboldt marten population in
California occurs in the north-central
portion of the described range in an area
dominated by Douglas-fir (Pseudotsuga
menzesii) and tanoak (Lithocarpus
densiflora) forest associations (Slauson
et al. 2007, p. 459). This population uses
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two structurally distinct, fog-influenced
forest types, one on serpentine (a
mineral or rock consisting of a hydrous
magnesium silicate and usually having
a dull green color and often a mottled
appearance) soils and one on more
productive non-serpentine soils
(Slauson 2003, p. 59; Slauson et al.
2009b, p. 3). The non-serpentine
habitats contain old-growth Douglas-fir
forests, and the serpentine types contain
mixed conifer forests that include
Douglas-fir, sugar pine (Pinus
lambertiana), western white pine (P.
monticola), and lodgepole pine (P.
contorta) (Slauson et al. 2009b, p. 3).
At the home range scale, Humboldt
martens in California select the largest
available patch sizes of old-growth, oldgrowth and late-mature (i.e., latesuccessional), and serpentine habitat
(Slauson et al. 2007, p. 466). Slauson et
al. (2009b, p. 12) found that the biggest
difference between sites in California
with stable Humboldt marten
occupancy versus unstable occupancy is
patch size of old-growth forest, with
sites with more stable Humboldt marten
occupancy associated with larger
patches of old-growth forest. The
probability that a Humboldt marten is
detected increases as the following
home range characteristics increase in
size: largest contiguous patch of latesuccessional forest; total amount of latesuccessional forest; and total area of
serpentine habitat (Slauson 2003, p. 67).
In non-serpentine habitats, coniferdominated, late-successional stands
with dense shrub cover in patches
greater than or equal to 445 ac (180 ha)
are estimated to be a minimum criterion
to identify potential Humboldt marten
home range areas (Slauson 2003, p. 70).
Compared to martens in the Sierra
Nevada and Cascade mountains,
Humboldt martens occupy lowelevation areas with little or no snowfall
and select forest habitats with some
distinctly different features, such as
dense, extensive shrub cover (Slauson et
al. 2009b, p. 3). Serpentine habitats
occupied by Humboldt martens have
open tree canopies, dense shrub cover,
and an abundance of boulder piles,
while non-serpentine sites have closed,
multi-layered tree canopies, dense shrub
cover, and older age-class stands
(Slauson 2003, p. 59). Serpentine sites
sometimes lack trees, suggesting that
dense shrub layers may provide the
necessary overhead cover (Slauson
2003, pp. 60–61). In addition, prey
species, such as chipmunks (Tamias
spp.) and golden-mantled ground
squirrels (Spermophilus lateralis), may
use boulder-sized surface rocks for
escape cover in serpentine sites where
trees are sparse (Slauson 2003, p. 61).
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Recent Humboldt marten population
monitoring suggests that serpentine
areas may represent lower quality
habitat than late-successional Douglasfir forest (Slauson et al. 2009b, p. 12).
In non-serpentine habitats, Humboldt
martens use old-growth stands much
more than expected based on
availability, use late-mature stands
commensurate with availability, and
make little or no use of all other seral
stages (Slauson et al. 2007, p. 462). All
earlier seral stages are selected against,
probably because of the lack of one or
more key structural features (Slauson
2003, p. 62). Dense shrub cover is the
most consistent habitat feature at sites
selected by Humboldt martens in both
serpentine and non-serpentine habitats
(Slauson et al. 2007, p. 465). Humboldt
martens show the strongest selection for
conifer stands with greater than 80
percent shrub cover and select against
stands with less than 60 percent shrub
cover (Slauson and Zielinski 2007b, p.
242). Plant species dominating the
shrub layers are shade-tolerant, longlived, mast- and berry-producing
species, including salal (Gaultheria
shallon), evergreen huckleberry
(Vaccinium ovatum), Pacific
rhododendron (Rhododendron
macrophyllum), and shrub oaks
(huckleberry oak (Quercus vaccinifolia)
and bush tanoak (Lithocarpus
densiflorus var. echinoides)) (Slauson
and Zielinski 2009, p. 42). In contrast,
Humboldt martens do not use
disturbance-associated species of
shrubs, such as Ceanothus spp. (Slauson
and Zielinski 2009, p. 42). Dense stands
of mature shrubs provide refuge from
predators, cover for prey species, and
mast (berries and acorns) for prey
species and Humboldt martens, and
such stands may also deter largerbodied competitors, such as fisher and
gray fox (Urocyon cinereoargenteus), by
limiting their foraging abilities (Slauson
and Zielinski 2009, p. 42). Shrubs also
contribute to the formation of some
resting locations and resting structures
(Slauson and Zielinski 2009, p. 42).
During the late summer and fall,
Humboldt martens in California used
cavities, den chambers, and broken tops
of standing dead trees for 87 percent of
their resting locations, and branch
platforms, ground sites, and basal
hollows for the remainder of their
resting locations (Slauson and Zielinski
2009, p. 39). Large snags were the most
frequently used resting structure with
mean diameter-at-breast-height (dbh) for
conifers of 36.6 in (93 cm) (Slauson and
Zielinski 2009, p. 40). Conifer logs used
as resting structures had a mean
diameter of 29.5 in (75 cm) (Slauson and
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Zielinski 2009, p. 40). Forty-two percent
of the resting structures used in
serpentine habitats were located in rock
and shrub clumps (Slauson and
Zielinski 2009, p. 40). All resting sites
in serpentine and non-serpentine
habitats had dense shrub cover (Slauson
and Zielinski 2009, p. 42).
Availability of denning habitat is
essential to successful recruitment and
persistence of American marten
populations (Ruggiero et al. 1998, p.
663). American marten natal dens, used
by mothers and neonatal young, are
typically located in cavities in very large
logs, snags, or live trees, while maternal
dens, used by mothers and older but
still dependent young, tend to be in less
specialized structures similar to resting
sites (Ruggiero et al. 1998, p. 663).
Slauson and Zielinski (2009, p. 40)
observed one adult female Humboldt
marten with a single kit at three
maternal den structures: (1) A 26-in (66cm) dbh live chinquapin (Chrysolepis
chrysophylla), (2) the broken top of a
44.5-in (113-cm) dbh live Douglas-fir,
and (3) in a 45.3-in (115-cm) dbh
Douglas-fir snag.
Evaluation of Information for This
Finding
Section 4 of the Act (16 U.S.C. 1533)
and its implementing regulations at 50
CFR part 424 set forth the procedures
for adding a species to, or removing a
species from, the Federal Lists of
Endangered and Threatened Wildlife
and Plants. A species may be
determined to be an endangered or
threatened species due to one or more
of the five factors described in section
4(a)(1) of the Act:
(A) The present or threatened
destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial,
recreational, scientific, or educational
purposes;
(C) Disease or predation;
(D) The inadequacy of existing
regulatory mechanisms; or
(E) Other natural or manmade factors
affecting its continued existence.
In considering what factors might
constitute threats, we must look beyond
the mere exposure of the species to the
factor to determine whether the species
responds to the 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 how
significant a threat it is. If the threat is
significant, it may drive or contribute to
the risk of extinction of the species,
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such that the species may warrant
listing as endangered or threatened as
those terms are defined by the Act. This
does not necessarily require empirical
proof of a threat. The combination of
exposure and some corroborating
evidence of how the species is likely
impacted could suffice. The mere
identification of factors that could
impact a species negatively may not be
sufficient to compel a finding that
listing may be warranted. The
information must contain evidence
sufficient to suggest that these factors
may be operative threats that act on the
species to the point that the species may
meet the definition of endangered or
threatened under the Act.
In making this 90-day finding, we
evaluated whether information
regarding threats to the Humboldt
marten, as presented in the petition and
in other information available in our
files, is substantial, thereby indicating
that the petitioned action may be
warranted. Our evaluation of this
information is presented below.
A. The Present or Threatened
Destruction, Modification, or
Curtailment of Habitat or Range
The petition states that the primary
cause of population decline and
extirpation of martens in coastal
northern California and coastal Oregon
is loss of old-growth coniferous forest
habitat due to logging (CBD and EPIC
2010, p. 20). According to the petition,
logging threatens Humboldt marten
populations because martens require
large areas of unfragmented, old-growth
forest to survive and because logging
reduces the amount of available habitat
and key Humboldt marten habitat
structural elements, such as large
standing and dead conifers, down
woody debris, and a dense understory of
shade-tolerant shrubs (CBD and EPIC
2010, pp. 20–23).
Zielinski et al. (2001, p. 487)
postulated that timber harvest in the
redwood region was the most plausible
reason for the continued absence of
Humboldt martens from most of the
coastal range of northwestern California.
Zielinski et al. (2001, p. 487) concluded
that because martens typically are
associated with old forests with a
diversity of large structural features, it is
likely that the intensity of timber
harvest, especially on private lands, has
reduced the habitat value over much of
the coastal northern California region.
Large areas of the Humboldt marten’s
range in California and Oregon are
located on private commercial
timberlands (Zielinski et al. 2001, pp.
478, 484; CBD and EPIC 2010, pp. 23,
32). Most of the areas within the
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Humboldt marten’s range in California
and Oregon not located on private lands
are located on U.S. Forest Service
(Forest Service) lands, but timber
harvesting occurs on most of these
Forest Service lands (CBD and EPIC
2010, pp. 23, 29–32).
The petition also states that over the
long-term, wildfire plays a role in
developing the habitat components on
which martens depend, but because the
Humboldt marten’s habitat has been so
severely reduced by logging, wildfires
are now a threat to the subspecies (CBD
and EPIC 2010, p. 24). Slauson and
Zielinski (2004, p. 63) reported that, due
to the subspecies’ critically low
population size and restricted range in
northwestern California, fire threatens
the Humboldt marten with short-term
loss and fragmentation of suitable
habitat. Fires in 1998 and 2008 burned
approximately 28 percent of the range
currently occupied by Humboldt marten
in northwestern California (Service
2010, p. 19). The Biscuit Fire, one of
Oregon’s largest fires in recorded
history, burned a total area of
approximately 500,000 ac (202,343 ha)
(Forest Service 2009), part of which
overlapped the range of the
southernmost population of Humboldt
marten in coastal Oregon. Fifty percent
of the total burn area burned very hot,
with more than 75 percent of the
vegetation killed (Forest Service 2009).
Post-fire site visits to some of the areas
burned in northwestern California in
2008 showed that the dense shrub
understory was removed, likely
reducing the suitability and increasing
fragmentation of these areas for the
Humboldt marten over the short term
(Slauson et al. 2009b, p. 11). In the cool,
moist coastal forests of northern
California, fires pose a relatively low
risk to the Humboldt marten and its
habitat. However, the habitat of the
current Humboldt marten population in
northwestern California occurs
primarily in the relatively warm and dry
Douglas-fir-tanoak communities farther
inland and at higher elevations and,
thus, is more vulnerable to lightningignited fires. Further, even low-intensity
fires can remove the dense shrub
understory that is important to
Humboldt martens, reducing habitat
quality and increasing fragmentation of
suitable habitat.
The petition states that recreational
activities, including off-highway
vehicles, snowmobiles, dirt bikes, and
camping could degrade marten habitat,
interfere with marten behavior, and
cause martens to shift to less suitable
habitat (CBD and EPIC 2010, p. 24). The
petition recognizes that threats posed to
Humboldt marten populations by
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recreation are unknown, and that due to
the remoteness of Humboldt marten
habitat and dense shrub cover preferred
by the subspecies, the threat posed by
recreation is likely low (CBD and EPIC
2010, p. 25). While certain recreational
activities may have localized impacts on
marten habitat, information in the
petition and in our files does not
indicate that recreational activities are
having population-level impacts that
threaten the Humboldt marten.
Summary for Factor A
In summary, we find that the
information provided in the petition, as
well as other information readily
available in our files, presents
substantial scientific or commercial
information indicating that the
petitioned action may be warranted due
to the present or threatened destruction,
modification, or curtailment of the
Humboldt marten’s habitat or range
from timber harvesting and fire. We will
review the possible effects of these
threats to Humboldt marten more
thoroughly in our status review.
B. Overutilization for Commercial,
Recreational, Scientific, or Educational
Purposes
The petition states that historical
trapping was the primary contributor to
the decline of martens in California,
including the portions of Humboldt, Del
Norte, and Siskiyou Counties where the
small extant population of the
Humboldt marten occurs (CBD and EPIC
2010, p. 25). In 1946, the California Fish
and Game Commission closed the
marten trapping season in all or parts of
Del Norte, Humboldt, Siskiyou, and
Trinity Counties due to declining
harvests (Twining and Hensley 1947,
p. 136). However, Humboldt marten
populations in coastal northern
California have not recovered, despite
decades of protection from trapping
(Slauson and Zielinski 2004, p. 61).
While trapping of martens as
furbearers in California is no longer
legal, the petition states that the threat
posed to Humboldt martens by
accidental capture and poaching in
California is magnified by other threats
such as small population size,
population isolation, and habitat
fragmentation from logging and fire
(CBD and EPIC 2010, p. 25). In
California, it is legal to trap other
mammals that may occur in Humboldt
marten habitat, including bobcats and
gray fox (California Code of Regulations,
Title 14, Sections 461 and 478), and
Humboldt martens may be captured
incidentally in traps set for these
species. Body-gripping traps (such as
steel-jawed leghold, padded leghold,
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conibear, and snares) were banned in
California in 1998 (California Fish and
Game Code Section 3003.1). Only nonbody-gripping traps, such as cage and
box live traps, are legal in California. No
information was provided in the
petition, nor is any information
available in our files, to determine the
extent of incidental trapping-related
injury or mortality from non-bodygripping traps. However, the use of box
or cage live traps suggests that, if
trapped, Humboldt martens are more
likely to be released alive and unharmed
than if body-gripping or other lethal trap
types were allowed. Due to the remote
location of habitat occupied by the
Humboldt marten and the above
restrictions, current mortalities and
injuries from incidental capture of
Humboldt martens in northwestern
California are likely rare.
Additionally, current scientific survey
techniques use nonlethal methods, such
as track-plates, camera stations, and live
traps, and are thus not likely to result
in population-level impacts to the
Humboldt marten. While injury from
accidental capture and poaching may
affect individual Humboldt martens in
California, neither information in the
petition nor information in our files
indicates that accidental capture and
poaching in California are likely to have
a population-level effect or threaten the
Humboldt marten.
Martens are still legally trapped as
furbearers in Oregon, and the petition
states that trapping remains a threat to
martens in coastal Oregon (CBD and
EPIC 2010, p. 25). The petition states
that the threat posed to Humboldt
martens by legal trapping in Oregon is
magnified by other threats such as small
population size, population isolation,
and habitat fragmentation from logging
and fire (CBD and EPIC 2010, p. 25).
Information in the petition indicates
that martens can be trapped throughout
Oregon between November 1 and
January 31 with the purchase of a
furtakers’ license (CBD and EPIC 2010,
p. 25). Although trapping mortality of
martens is a potential concern because
marten populations in coastal Oregon
are considered small and isolated (see
Population Status section), most
martens trapped in Oregon are taken
from the Cascade Range and Blue
Mountains, and trapping harvest of
martens in the Oregon Coast Range is
rare (Oregon Department of Fish and
Wildlife 2010). We therefore conclude
that information presented in the
petition and available in our files does
not indicate that furbearer trapping in
Oregon is a threat to Humboldt marten.
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Summary for Factor B
In summary, we find that the
information provided in the petition, as
well as other information readily
available in our files, does not present
substantial scientific or commercial
information indicating that the the
petitioned action may be warranted due
to overutilization. However, we will
review the possible effects of furbearer
trapping in Oregon on Humboldt marten
more thoroughly in our status review.
C. Disease or Predation
Disease
The petition recognizes that disease in
the Humboldt marten has not been
studied, but states that the Humboldt
marten is potentially threatened by
disease given the subspecies’ extremely
small population size (CBD and EPIC
2010, p. 26). Numerous pathogens are
known to cause severe disease in
mustelids (Brown et al. 2008, pp. 5–6),
but disease exposure in the Humboldt
marten has not been studied. Strickland
et al. (1982, p. 607) noted that American
martens in their study area in central
Ontario, Canada, tested positive for
toxoplasmosis, Aleutian disease (a
carnivore parvovirus), and leptospirosis;
however, none of these was known to be
a significant mortality factor. Brown et
al. (2008) determined rates of pathogen
exposure for the congeneric (member of
the same genus, Martes) fisher in
northwestern California on the Hoopa
Valley Indian Reservation—located less
than 6.2 mi (10 km) south of the nearest
Humboldt marten verified detection—
and demonstrated that fishers were
exposed to several serious pathogens
including canine distemper virus,
canine parvovirus, and West Nile virus.
Of the 15 radio-collared fishers found
dead on the Hoopa Valley Indian
Reservation during the pathogen study,
2 had been exposed to canine distemper
virus and 6 to canine parvovirus (Brown
et al. 2008, p. 3). Evidence of canine
distemper virus infection has been
reported in all families of terrestrial
carnivores, including the family
Mustelidae that includes martens and
fishers (Deem et al. 2000, p. 441). In
fact, mustelids are among the species
most susceptible to canine distemper
disease (Deem et al. 2000, p. 443). For
example, black-footed ferrets (Mustela
nigripes) are highly susceptible to
natural canine distemper infection and
have a fatality rate close to 100 percent
(Bernard et al. 1984). Because canine
distemper is highly contagious, and
viral shedding may follow infection for
60–90 days (Greene and Appel 1990), it
is reasonable to assume that infected
fishers on the Hoopa Valley Indian
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Reservation, especially dispersing
juveniles, could infect the nearby
Humboldt marten population. Even at
low exposure rates, canine distemper
has the potential to be a threat to one
or more of the small extant Humboldt
marten populations.
Research cited in the petition and
information in our files indicates that
fishers located in close proximity to
Humboldt marten occurrences in
northwestern California have been
exposed to canine distemper, a disease
that can be transmitted between
different species of carnivores and that
can cause high levels of mortality in
carnivores, including species within the
Mustelidae family. Estimated size of the
northwestern California Humboldt
marten population is small, so an
outbreak of canine distemper or other
lethal carnivore disease could have a
population-level impact and pose a
threat to this population.
Predation
The petition states that predation is a
significant threat to the Humboldt
marten, especially because the
subspecies is highly vulnerable to
mortality events and further population
decline due to its small population size
(CBD and EPIC 2010, p. 25). Timber
harvesting practices that result in
reduced shrub layers may result in
increased vulnerability of Humboldt
martens to predation by larger
carnivores, such as fishers and gray
foxes. Fishers and gray foxes typically
occupy forest types where shrub
densities are naturally lower and are
rarely detected in coastal forest with
extensive shrub cover (Slauson and
Zielinski 2007b, p. 242). Dense,
spatially extensive shrub layers may
provide smaller-bodied Humboldt
martens an advantage over other largerbodied carnivores (Slauson et al. 2007,
p. 466), so that the removal of these
layers may put the Humboldt marten at
risk of increased predation. Although
there may be associations between
shrub cover and risk of predation in
forests where Humboldt martens occur,
we did not find information in the
petition or in our files indicating that
elevated predation rates may be a threat
to the continued existence of Humboldt
martens.
The petition states that recreational
activities, including off-highway
vehicles, dirt bikes, hiking, and
camping, could affect Humboldt marten
behavior, possibly exposing the
Humboldt marten to increased
predation. The petition acknowledges
that the level of the threat from these
recreational activities is unknown, but
likely low due to the remoteness of the
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currently occupied range of the
Humboldt marten. We conclude that
information in the petition and
information in our files does not
support the assertion in the petition that
predation is a threat to Humboldt
marten.
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Summary of Factor C
In summary, we find that the
information provided in the petition, as
well as other information readily
available in our files, presents
substantial scientific or commercial
information indicating that the
petitioned action may be warranted due
to disease as a result of the threat posed
by canine distemper or other lethal
carnivore diseases on Humboldt marten.
We will review the possible effects of
these threats to Humboldt marten more
thoroughly in our status review.
D. The Inadequacy of Existing
Regulatory Mechanisms
The petition states that existing
regulatory mechanisms do not
adequately protect the Humboldt marten
on Federal, State, tribal, or private lands
(CBD and EPIC 2010, pp. 28–33). The
petition further states that martens are
still legally trapped in coastal Oregon
and that existing regulatory mechanisms
are inadequate to protect habitat for the
martens in coastal northern California
and coastal Oregon (CBD and EPIC
2010, p. 28).
The petition states that large areas of
the Humboldt marten’s historical range
and current range occur on privately
owned commercial timberlands where
existing regulatory mechanisms do not
protect Humboldt martens from habitat
loss and degradation due to timber
harvesting (CBD and EPIC 2010, p. 29).
As mentioned in the Factor A section
above, large areas of the Humboldt
marten’s current range in coastal
northern California and coastal Oregon
occur on private commercial
timberland. Information in our files
supports the assertion that forest
management practices on these private
commercial timberlands may not be
compatible with habitat management for
martens (see Factor A; Zielinski et al.
2001, pp. 483–488).
The petition also states that existing
regulatory mechanisms on Federal
Forest Service lands are not adequate to
protect Humboldt martens from habitat
loss and degradation due to timber
harvesting (CBD and EPIC 2010, pp. 28–
29). The petition acknowledges that the
American marten is recognized as a
Forest Service sensitive species in
California, but not in Oregon (CBD and
EPIC 2010, p. 29); however, the petition
goes on to state that the sensitive
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species status in California does not
provide nondiscretionary protections
and thus is not considered an adequate
regulatory mechanism (CBD and EPIC
2010, p. 29). The petition also states that
large areas of the Humboldt marten’s
current range on Forest Service lands
are designated as matrix lands under the
Northwest Forest Plan (NWFP), and that
timber harvesting that may be
incompatible with Humboldt marten
habitat management is allowed on
matrix lands (CBD and EPIC 2010, pp.
29–30). The NWFP was adopted in 1994
to guide the management of 37,500 sq
mi (97,125 sq km) of Federal lands in
portions of western Washington and
Oregon, and northwestern California.
Implementation of the NWFP was
intended to provide, over time, a
network of large blocks of latesuccessional forest habitat connected by
riparian reserves. However, even with
NWFP implementation, timber harvest,
fuels reduction projects, and road
construction may continue to result in
the loss and fragmentation of occupied
and suitable but unoccupied Humboldt
marten habitat throughout a substantial
portion of its range in coastal Oregon
and northwestern California. Protections
for late-successional forest habitats
provided for species such as the
northern spotted owl (Strix occidentalis
caurina) and marbled murrelet
(Brachyramphus marmoratus), which
are listed as threatened under the Act,
provide certain protections for marten
habitat but may not provide sufficient
protections for certain habitat elements
known to be important for Humboldt
martens, such as shade-tolerant shrub
cover.
Summary of Factor D
In summary, we find that the
information provided in the petition, as
well as other information readily
available in our files, presents
substantial scientific or commercial
information indicating that the
petitioned action may be warranted due
to the inadequacy of existing regulatory
mechanisms that address habitat threats
associated with timber harvesting and
forest management. We will review the
possible effects of these threats on
Humboldt marten more thoroughly in
our status review.
E. Other Natural or Manmade Factors
Affecting Its Continued Existence
The petition states that several other
factors threaten the continued existence
of the Humboldt marten, including
small population size effects; mortality
from vehicle strikes, poisoning, and
starvation; and global climate change
(CBD and EPIC 2010, pp. 27–28).
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The petition states that widespread
timber harvesting has resulted in
drastically reduced suitable habitat for
Humboldt marten, and that existing
populations in California and coastal
Oregon are small and isolated (CBD and
EPIC 2010, p. 27). The smaller a
population becomes, the more
susceptible it is to stochastic (random)
demographic and environmental
variation and to genetic factors that tend
to reduce population size even more
and that may push the population to
extinction (Primack 1993, p. 274).
Primack (1993, p. 335) found that
population size was the best predictor of
extinction probability. Slauson et al.
(2009b, p. 5) used multi-season
occupancy modeling to estimate the
probability of extinction and
colonization (probability that Humboldt
martens in northwestern California
would reoccupy currently unoccupied
suitable habitat) and found that the
probability of extinction was higher
than the probability of colonization
(Slauson et al. 2009b, p. 10). As
mentioned in the Species Information
section, for a mammal of its size,
American martens—and presumably
Humboldt martens—have a relatively
low reproductive rate, suggesting a slow
recovery from population-level impacts.
Species with low rates of population
increase are often unable to rebuild their
populations fast enough to avoid
extinction following habitat loss
(Primack 1993, p. 102). As mentioned in
the Population Status section, it is
estimated that the extant Humboldt
marten population in coastal northern
California contains fewer than 100
individuals and is believed to be
declining, and the two coastal Oregon
populations are also considered to be
small and in decline. Information in our
files supports the assertion in the
petition that current Humboldt marten
populations in coastal northern
California and coastal Oregon are
vulnerable to extinction processes due
to small and isolated populations
(Slauson et al. 2007, p. 458; Slauson et
al. 2009b, p. 13).
The petition states that the Humboldt
marten is threatened by several sources
of mortality including vehicle strikes,
poisoning, and starvation (CBD and
EPIC 2010, p. 28). Zielinski et al. (2001,
p. 484) noted that 10 marten road kills
had been reported from coastal central
Oregon between 1980 and 1998, while
no marten road kills had been reported
in coastal California. We acknowledge
that Humboldt martens are occasionally
killed by vehicles along highways, but
we do not consider the numbers
reported by Zielinski et al. (2001, p.
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484) to be sufficiently great to threaten
the continued existence of the
Humboldt marten, nor do we have
information in our files indicating that
mortality from vehicle collisions
threatens martens in coastal northern
California and coastal Oregon. The
petition also states that martens are
vulnerable to mortality from starvation
and poisoning, although the petition
acknowledges that the extent of the
threat of these factors to the Humboldt
marten has not been quantified (CBD
and EPIC 2010, p. 28). We conclude that
information in the petition and in our
files does not indicate that mortality
from poisoning or starvation threatens
the continued existence of martens in
coastal northern California and coastal
Oregon. However, we will evaluate
these potential threats more thoroughly
in our 12-month finding.
The petition further states that global
climate change threatens the Humboldt
marten (CBD and EPIC 2010, p. 28).
According to the petition, vegetation
changes resulting from climate change
could cause changes in the type and
availability of prey for martens and
could affect availability of resting and
denning sites, shrub cover, and canopy
cover. The petition also states that
climate change could lead to tree
mortality from insect infestation,
disease, and drought. While we
acknowledge that climate change will
result in a variety of environmental
changes including changes in vegetation
composition and structure, information
presented in the petition is too general
and speculative to determine whether
climate change effects may threaten the
continued existence of the Humboldt
marten, and we do not have specific
information available in our files
indicating that climate change threatens
the continued existence of the
Humboldt marten.
Summary of Factor E
In summary, we find that the
information provided in the petition, as
well as other information readily
available in our files, presents
substantial scientific or commercial
information indicating that the
petitioned action may be warranted due
to other natural or manmade factors
affecting its continued existence,
specifically small population effects. We
will review threats posed by small
population effects more thoroughly
during our status review.
Finding
On the basis of our determination
under section 4(b)(3)(A) of the Act, we
determine that the petition presents
substantial scientific or commercial
VerDate Mar<15>2010
14:14 Jan 11, 2012
Jkt 226001
information indicating that listing the
Humboldt marten throughout all or a
significant portion of its range may be
warranted. This finding is based on
substantial information provided in the
petition and in our files for Factor A,
Factor C, Factor D, and Factor E. We
determine that the information provided
under Factor B is not substantial.
Because we have found that the
petition presents substantial
information indicating that listing the
Humboldt marten may be warranted, we
are initiating a status review to
determine whether listing the Humboldt
marten under the Act is warranted.
Because ongoing genetics research may
result in changes to American marten
taxonomy, we will examine whether the
purported subspecific designation of
Humboldt marten is appropriate during
our status review. If the Humboldt
marten does not maintain its status as a
subspecies, we will examine during our
status review whether the Humboldt
marten meets criteria for designation as
a distinct population segment under our
February 7, 1996, DPS policy (61 FR
4722).
The ‘‘substantial information’’
standard for a 90-day finding differs
from the Act’s ‘‘best scientific and
commercial data’’ standard that applies
to a status review to determine whether
a petitioned action is warranted. A 90day finding does not constitute a status
review under the Act. In a 12-month
finding, we will determine whether a
petitioned action is warranted after we
have completed a thorough status
review of the species, which is
conducted following a substantial 90day finding. Because the Act’s standards
for 90-day and 12-month findings are
different, as described above, a
substantial 90-day finding does not
mean that the 12-month finding will
result in a warranted finding.
References Cited
A complete list of references cited is
available on the Internet at https://
www.regulations.gov and upon request
from the Arcata Fish and Wildlife Office
(see FOR FURTHER INFORMATION CONTACT
section).
Authors
The primary authors of this document
are the staff members of the Arcata Fish
and Wildlife Office (see FOR FURTHER
INFORMATION CONTACT section).
Authority
The authority for this action is the
Endangered Species Act of 1973, as
amended (16 U.S.C. 1531 et seq.).
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Dated: December 30, 2011.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife
Service.
[FR Doc. 2012–479 Filed 1–11–12; 8:45 am]
BILLING CODE 4310–55–P
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
50 CFR Part 622
RIN 0648–AY74
Fisheries of the Caribbean, Gulf of
Mexico, and South Atlantic; SnapperGrouper Fishery Off the Southern
Atlantic States; Amendment 20A
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice of availability; request
for comments.
AGENCY:
NMFS announces that the
South Atlantic Fishery Management
Council (Council) has submitted
Amendment 20A to the Fishery
Management Plan (FMP) for the
Snapper-Grouper Fishery of the South
Atlantic Region (Amendment 20A) for
review, approval, and implementation
by NMFS. Amendment 20A proposes
actions for the wreckfish individual
transferable quota (ITQ) program,
including actions to define and revert
inactive wreckfish quota shares,
redistribute reverted quota shares to
remaining shareholders, establish a cap
on the number of wreckfish quota shares
a single entity may own, and establish
an appeals process for redistribution of
reverted wreckfish quota shares. The
actions contained in Amendment 20A
are intended to help achieve the
optimum yield (OY) from the wreckfish
commercial sector in accordance with
the Magnuson-Stevens Fishery
Conservation and Management Act
(Magnuson-Stevens Act).
DATES: Written comments must be
received on or before March 12, 2012.
ADDRESSES: You may submit comments
on the amendment identified by
‘‘NOAA–NMFS–2011–0277’’ by any of
the following methods:
• Electronic submissions: Submit
electronic comments via the Federal eRulemaking Portal: https://
www.regulations.gov. Follow the
instructions for submitting comments.
• Mail: Nikhil Mehta, Southeast
Regional Office, NMFS, 263 13th
Avenue South, St. Petersburg, FL 33701.
SUMMARY:
E:\FR\FM\12JAP1.SGM
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]]>Agencies
[Federal Register Volume 77, Number 8 (Thursday, January 12, 2012)]
[Proposed Rules]
[Pages 1900-1908]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-479]
=======================================================================
-----------------------------------------------------------------------
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; 90-Day Finding on
a Petition To List the Humboldt Marten as Endangered or Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of petition finding and initiation of status review.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day finding on a petition to list the Humboldt marten (Martes
americana humboldtensis) as endangered or threatened and designate
critical habitat under the Endangered Species Act of 1973, as amended
(Act). Based on our review, we find that the petition presents
substantial scientific or commercial information indicating that
listing the Humboldt marten may be warranted. Therefore, with the
publication of this notice, we are initiating a review of the status of
the Humboldt marten to determine if listing is warranted. To ensure
that this status review is comprehensive, we are requesting scientific
and commercial data and other information regarding the Humboldt
marten. Based on the status review, we will issue a 12-month finding on
the petition, which will address whether the petitioned action is
warranted, as provided in section 4(b)(3)(B) of the Act.
DATES: To allow us adequate time to conduct this review, we request
that we receive information on or before March 12, 2012. The deadline
for submitting an electronic comment using the Federal eRulemaking
Portal (see ADDRESSES section, below) is 11:59 p.m. Eastern Time on
this date. After March 12, 2012, you must submit information directly
to the Field Office (see FOR FURTHER INFORMATION CONTACT section
below). Please note that we might not be able to address or incorporate
information that we receive after the above requested date.
ADDRESSES: You may submit information by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Enter Keyword or ID box, enter Docket No.
FWS-R8-ES-2011-0105, which is the docket number for this action. Then
click on the Search button. You may submit a comment by clicking on
``Send a Comment or Submission.''
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R8-ES-2011-0105; Division of Policy and
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax
Drive, MS 2042-PDM; Arlington, VA 22203.
We will post all information we receive on https://www.regulations.gov. This generally means that we will post any
personal identifying information you provide us (see the Request for
Information section below for more details).
FOR FURTHER INFORMATION CONTACT: Nancy J. Finley, Field Supervisor; by
mail at Arcata Fish and Wildlife Office, 1655 Heindon Road, Arcata, CA
95521; 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:
Request for Information
When we make a finding that a petition presents substantial
information indicating that listing a species may be warranted, we are
required to promptly review the status of the species (status review).
For the
[[Page 1901]]
status review to be complete and based on the best available scientific
and commercial information, we request information on the Humboldt
marten from governmental agencies, Native American tribes, the
scientific community, industry, and any other interested parties. We
seek information on:
(1) The Humboldt marten's biology, range, and population trends,
including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the Humboldt marten,
its habitat, or both.
(2) The factors that are the basis for making a listing
determination for a species under section 4(a) of the Act (16 U.S.C.
1531 et seq.), which are:
(a) The present or threatened destruction, modification, or
curtailment of Humboldt marten habitat or its 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.
If, after the status review, we determine that listing the Humboldt
marten is warranted, we will propose critical habitat (see definition
in section 3(5)(A) of the Act) under section 4 of the Act, to the
maximum extent prudent and determinable at the time we propose to list
the species. Therefore, we also request data and information on:
(1) What may constitute ``physical or biological features essential
to the conservation of the species,'' within the geographical range
currently occupied by the species;
(2) Where these features are currently found;
(3) Whether any of these features may require special management
considerations or protection;
(4) Specific areas outside the geographical area occupied by the
species that are ``essential for the conservation of the species;''and
(5) What, if any, critical habitat you think we should propose for
designation if the species is proposed for listing, and why such
habitat meets the requirements of section 4 of the Act.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Submissions merely stating support for or opposition to the action
under consideration without providing supporting information, although
noted, will not be considered to provide the best information to
support a determination. Section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or threatened
species must be made ``solely on the basis of the best scientific and
commercial data available.''
You may submit your information concerning this status review by
one of the methods listed in the ADDRESSES section. If you submit
information via https://www.regulations.gov, your entire submission--
including any personal identifying information--will be posted on the
Web site. If your submission is made via a hardcopy that includes
personal identifying information, you may request at the top of your
document that we withhold this personal identifying information from
public review. However, we cannot guarantee that we will be able to do
so. We will post all hardcopy submissions on https://www.regulations.gov.
Information and supporting documentation that we received and used
in preparing this finding is available for you to review at https://www.regulations.gov, or by appointment, during normal business hours,
at the U.S. Fish and Wildlife Service, Arcata Fish and Wildlife Office
(see FOR FURTHER INFORMATION CONTACT section, above).
Background
Section 4(b)(3)(A) of the Act requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted. We are to base this finding on
information provided in the petition, supporting information submitted
with the petition, and information otherwise available in our files. To
the maximum extent practicable, we are to make this finding within 90
days of our receipt of the petition and publish our notice of the
finding promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly conduct a species status review, which we subsequently
summarize in our 12-month finding.
Petition History
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 the
Humboldt marten (Martes americana humboldtensis), a subspecies of the
American marten, be listed as endangered or threatened and that
critical habitat be designated in accordance with the Act. The document
received clearly identified itself as a petition and included the
requisite identification information for the petitioners, as required
by 50 CFR 424.14(a). 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. This finding addresses the petition.
Listable Entity Evaluation
Under section 3(16) of the Act, we may consider for listing any
species or subspecies of fish, wildlife, or plants, or any distinct
population segment of vertebrate fish or wildlife which interbreeds
when mature. Such entities are considered eligible for listing under
the Act (and are, therefore, referred to as ``listable entities'')
should they be determined to meet the definition of an endangered or
threatened species. The petition states that genetics research
indicates that the currently recognized species American marten (Martes
americana) should be divided into two species--M. americana and M.
caurina (CBD and EPIC 2010, p. 6). The petition indicates that if
marten taxonomy is changed in the near future, the currently recognized
subspecies Humboldt marten (M. americana humboldtensis) would likely be
designated a subspecies of the newly designated species, M. caurina,
and thus would likely be renamed M. caurina humboldtensis. Therefore,
the petition requested listing as endangered or threatened one of the
following: (1) The currently recognized Humboldt marten subspecies, M.
americana humboldtensis; or (2) the Humboldt marten subspecies that may
be redesignated as M. caurina humboldtensis; or (3) the Humboldt marten
as a distinct population segment (DPS) of M. caurina (CBD and EPIC
2010, pp. 2, 6).
[[Page 1902]]
Historically, marten populations in coastal Oregon have not been
included within the range of the Humboldt marten (see Taxonomy and
Distribution section, below). The petition indicates, however, that
because recent genetics research indicates that populations of American
martens in coastal Oregon (currently Martes americana caurina) are more
closely related to Martes americana humboldtensis in coastal northern
California than to Martes americana caurina populations in the Cascade
Range of Oregon (Slauson et al. 2009a, pp. 1339-1340), the petitioned
and listable entity should include all marten populations in coastal
northern California and coastal Oregon (CBD and EPIC 2010, pp. 7-10).
The standard of review for a 90-day petition finding is ``that
amount of information that would lead a reasonable person to believe
that the measure proposed in the petition may be warranted.'' We
determine that the petition has met the threshold for review in its
characterization of currently designated American marten (M. americana)
populations in coastal northern California and coastal Oregon as a
potential listable entity. In our status review, we will thoroughly
review all information relevant to the taxonomic status of Humboldt
martens. For the purposes of this 90-day finding, the common name
Humboldt marten refers to currently described American marten (M.
americana) populations in coastal northern California and coastal
Oregon, based on the rationale provided in the petition (CBD and EPIC
2010, pp. 2, 6-8, 10) and research by Slauson et al. (2009a, pp. 1339-
1340).
Species Information
Taxonomy and Distribution
The Humboldt marten (Martes americana humboldtensis) is a
subspecies of the American marten and was first described by Grinnell
and Dixon (1926, p. 411). The Humboldt marten is classified in the
mammalian order Carnivora, family Mustelidae (weasels, otters,
badgers), and subfamily Mustelinae (martens, fisher, wolverine,
weasels). Clarke et al. (1987, p. 1) recognized eight subspecies of the
American marten; Wilson and Reeder (2005, p. 608) recognized 12
subspecies; and Hall and Kelson (1959, p. 900) and Hall (1981, pp. 981-
985) recognized 14 subspecies. Differences between the subspecies are
based on morphological and pelage characteristics (Hall and Kelson
1959, p. 900; Hall 1981, pp. 983-984) or cranial characters and fossil
history (Clarke et al. 1987, p. 1). The Humboldt marten is recognized
as a distinct subspecies of the American marten by all of the
aforementioned authors.
The American marten occurs throughout northern North America,
reaching its southjrnmost extent in the Sierra Nevada of California and
the southern Rocky Mountains of New Mexico (Gibilisco 1994, p. 66). The
historical range of the Humboldt marten is based on the catch of
licensed trappers in California for the 5-year period 1919-1924
(Grinnell and Dixon 1926, p. 415), and includes coastal northern
California, throughout the coast redwood (Sequoia sempervirens) zone
from the Oregon border south to Sonoma County (Grinnell and Dixon 1926,
p. 415; Grinnell 1933, p. 100; Grinnell et al. 1937, p. 209).
Historically, M. a. caurina has been recognized to occur north of the
coast redwood zone in western Oregon, Washington, and British Columbia
(Bailey 1936, p. 296; Hall 1981, p. 983; Zielinski et al. 2001, p.
479).
In northwestern California, the Klamath River separates the
historical range of the Humboldt marten from the range of the Sierra
Nevada marten (M. a. sierrae), which occurs from the Salmon-Trinity
Mountains in interior northwestern California, east to the Cascades,
and south throughout the Sierra Nevada (Hall 1981, p. 983; Zielinski et
al. 2001, p. 479). Slauson and Zielinski (2004, p. 62) suggest that the
xeric forest types in the river's canyon may act as a physical barrier
between these two subspecies.
In 2009, Slauson et al. (2009a, p. 1338) compared mitochondrial DNA
sequence diversity of martens from extant marten populations within the
described ranges of M. a. humboldtensis, M. a. caurina, and M. a.
sierrae, with a 1927 museum specimen of M. a. humboldtensis. Martens
from coastal northern California share a haplotype with the 1927 museum
specimen, supporting the hypothesis that the existing population in
coastal northern California represents descendants of the historical
population of Humboldt martens described by Grinnell and Dixon in 1926
(Slauson et al. 2009a, p. 1337). However, this same haplotype also
occurs in coastal Oregon populations of M. a. caurina, but is absent
from the Oregon Cascades population of M. a. caurina and from M. a.
sierrae, indicating that martens of coastal Oregon are genetically more
similar to martens from coastal northern California than they are to
martens in the Oregon Cascades (Slauson et al. 2009a, p. 1340). The
results further suggest that the historically defined range boundary
between M. a. humboldtensis and M. a. caurina at the Oregon-California
border may not be valid, and that coastal Oregon martens are part of
the same taxonomic group as Humboldt martens in coastal northern
California (Slauson et al. 2009a, p. 1340). Slauson et al. (2009a, p.
1340) concluded that, even though the coastal northern California and
coastal Oregon marten populations share a common haplotype, due to
small sample sizes, additional genetic analyses are necessary to
confirm the genetic relationship. Slauson et al. (2009a, p. 1337) noted
that there are no known contemporary or historical biogeographic
barriers to prevent north-south movement of martens between coastal
northern California and coastal Oregon. Therefore, a genetic
relationship between coastal marten populations in northern California
and Oregon would not be unexpected. As described above in Listable
Entity Evaluation, for the purposes of this 90-day finding, we conclude
that substantial information was provided in the petition indicating
that M. americana populations in coastal northern California and
coastal Oregon may constitute a valid listable entity. We will evaluate
all relevant information on genetics and taxonomy in our status review.
Population Status
Zielinski and Golightly (1996) reviewed all published and
unpublished historical information on the Humboldt marten, and the
results of contemporary (1989-1995) field surveys conducted within its
historical range, to determine the status of the subspecies in the
redwood zone of California (redwoods also occur in adjacent Curry
County, Oregon). They concluded that the marten population in the
northern Coast Ranges of California significantly declined during the
20th century and that the last verifiable record was 50 years old,
suggesting the subspecies was very rare, if not extinct. However, in
1996 and 1997, martens were detected at two survey stations in
northwestern California on the Six Rivers National Forest (Zielinski et
al. 1998, p. 1). These 1996-1997 presence-absence marten surveys were
conducted within presumed suitable habitat, throughout the historical
range of the Humboldt marten in northwestern California as well as in
extreme southern coastal Oregon. Besides the marten detections in
northwestern California, martens were also detected at survey stations
within 3 of the 19 sample units placed in southern coastal Oregon
(Zielinski et al. 1998, p. 2). The southern-most Oregon detection is
over 50 miles (mi)
[[Page 1903]]
(80 kilometers (km)) from the nearest California detection. Much of the
habitat in this intervening area is suitable for martens, but
presumably unoccupied as of the late 1990s.
The coastal northern California marten population rediscovered in
1996 and 1997 is located in the north-central portion of the described
range for M. a. humboldtensis (Grinnell and Dixon 1926, p. 413; Slauson
et al. 2009a, p. 1338). Based on results of a 2000-2001 grid-based
survey of the single marten population rediscovered in coastal northern
California in 1996, Slauson et al. (2009b, p. 13) concluded that the
entire Humboldt marten population in California likely consists of
fewer than 100 individuals. The Humboldt marten appears to have been
extirpated from greater than 95 percent of the range it occupied in
California in the early 1900s (Grinnell et al. 1937, p. 209), with the
single known extant population occupying an estimated area of only
170,000 acres (ac) (68,797 hectares (ha)) (Service 2010, p. 34).
Further, the Humboldt marten population in California is estimated to
have undergone a 42 percent decline in occupancy between grid-based
surveys conducted in 2000-2001 and 2008 (Slauson et al. 2009b, p. 10).
Martens in coastal Oregon are currently known from only two
disjunct populations--one in central coastal Oregon and one in southern
coastal Oregon--both of which are believed to be in decline based
mainly on a reduction in the number of martens trapped and anecdotal
observations over time (Zielinski et al. 2001, p. 478; Slauson and
Zielinski 2009, p. 36). No systematic grid-based surveys have been
conducted on, nor population estimates made for, the two populations of
martens in coastal Oregon. Concerns about the viability of the two
known marten populations in coastal Oregon have been expressed (Slauson
et al. 2009a, p. 1340).
Published literature on the Humboldt marten largely deals with
distribution, habitat selection, home range, diet, and genetics. Little
is known about Humboldt marten reproductive biology, demographics,
disease, or predation. Where data specific to the Humboldt marten are
lacking, we present published information for other American marten
subspecies, with the supposition that all subspecies of the American
marten share certain characteristics and behaviors.
Biology
The American marten has a long, slender body with relatively large
rounded ears, short limbs, and bushy tail (Clark et al. 1987, p. 1).
American martens have triangular faces with muzzles less pointed than
those of foxes. The tail constitutes about one-third of the total body
length (Powell et al. 2003, p. 636). Each well-furred paw includes five
toes (Powell et al. 2003, p. 636). Total length of American martens is
between 19.7 and 26.8 inches (in) (50 and 68 centimeters (cm)) and
adults weigh 1.1 to 3.1 pounds (lb) (0.5 to 1.4 kilograms (kg)),
depending on sex and subspecies (Buskirk and McDonald 1989, p. 999);
males are 20 to 40 percent larger than females (Buskirk and Zielinski
1997, p. 17). The color of the long, silky, dense fur ranges from pale
yellowish buff to tawny brown to almost black (Clark et al. 1987, p.
1). The color of the head is usually lighter than the body, and the
legs and tail are darker (Clark et al. 1987, p. 1).
Compared to the Sierra Nevada marten, the other subspecies of
American marten that occurs in California, the Humboldt marten is
reported to be darker, with a richer golden tone, and to have less
orange and yellow in the throat patch, a smaller skull (Grinnell and
Dixon 1926, p. 411), and smaller and less crowded premolars and molars
(Buskirk and Zielinski 1997, p. 17). Grinnell et al. (1937, p. 207)
added that the Humboldt marten had ``* * * far less orange-yellow color
on the throat and chest, and the usual area of this color is much
broken up by coarse spots and marblings of body brown.'' Hagmeier
(1961, p. 124) describes the Humboldt marten as a very small marten,
perhaps the smallest subspecies of American marten.
Sexual maturity for American martens occurs by 1 year of age, but
effective breeding may not occur before 2 years of age (Powell et al.
2003, p. 638). Mating occurs in July or August and the gestation period
varies from 220 to 276 days (Strickland et al. 1982, p. 602). Birth
occurs in late March or April, due to delayed implantation in which the
embryos remain in a state of arrested development (Strickland et al.
1982, p. 602). Kits are completely dependent at birth and weaned at
about 42 days (Buskirk and Ruggiero 1994, p. 17). The male apparently
takes no part in rearing the young, which disperse in late summer or
autumn (Strickland et al. 1982, p. 603). American martens produce an
average of slightly less than three young per female with one litter
per year (Strickland et al. 1982, p. 602). For a mammal of their size,
American martens have relatively low reproductive rates, but are long-
lived (up to 15 years in captivity and 14.5 years in the wild)
(Strickland and Douglas 1987, p. 535), suggesting a relatively slow
potential recovery rate from population-level impacts (Buskirk and
Ruggiero 1994, p. 16).
Slauson and Zielinski (2007a, p. 55) characterized the diet of
Humboldt martens by scat analysis and found that mammals (in 93 percent
of scats) and berries (in 85 percent of scats) were the most frequently
occurring items, followed by birds (in 21 percent of scats), insects
(in 20 percent of scats), and reptiles (in 7 percent of scats). Sciurid
rodents (especially Tamias species (spp.)) and Murid voles
(Clethrionomys californicus and Arborimus spp.) were the most common
mammal species found in Humboldt marten scats (Slauson and Zielinski
2007a, p. 55). The frequency of berries in the diet of the Humboldt
marten was the highest reported in diet studies of the American marten;
the frequency of birds was also among the highest reported (Slauson and
Zielinski 2007a, p. 55).
Strickland et al. (1982, p. 607) summarized reports of American
martens being preyed upon by coyotes (Canis latrans), fishers (Martes
pennanti), red foxes (Vulpes vulpes), cougars (Puma concolor), eagles
(Aquila chrysaetos and Haliaeetus leucocephalus), and great horned owls
(Bubo virginianus). Bull and Heater (2001, p. 3), in their northeastern
Oregon study area, documented 18 American martens killed by predators:
8 by bobcats (Lynx rufus), 4 by raptors, 4 by other American martens,
and 2 by coyotes.
Slauson and Zielinski (2006, p. 65) estimated seasonal (summer-
fall) home range size for Humboldt martens in California using the 100
percent minimum convex polygon method (a polygon created by drawing a
line connecting the outer locations). Adult male home ranges averaged
1,322 ac (535 ha); the home range for a single adult female with one
kit was 315 ac (127 ha). Juvenile female home ranges averaged 1,491 ac
(603 ha); the single juvenile male home range was 453 ac (183 ha).
Habitat
Historical records of the distribution of Humboldt martens in
California suggest that the subspecies was closely tied to coastal old-
growth redwood forests (Slauson et al. 2003, p. 3). However, the one
known remnant Humboldt marten population in California occurs in the
north-central portion of the described range in an area dominated by
Douglas-fir (Pseudotsuga menzesii) and tanoak (Lithocarpus densiflora)
forest associations (Slauson et al. 2007, p. 459). This population uses
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two structurally distinct, fog-influenced forest types, one on
serpentine (a mineral or rock consisting of a hydrous magnesium
silicate and usually having a dull green color and often a mottled
appearance) soils and one on more productive non-serpentine soils
(Slauson 2003, p. 59; Slauson et al. 2009b, p. 3). The non-serpentine
habitats contain old-growth Douglas-fir forests, and the serpentine
types contain mixed conifer forests that include Douglas-fir, sugar
pine (Pinus lambertiana), western white pine (P. monticola), and
lodgepole pine (P. contorta) (Slauson et al. 2009b, p. 3).
At the home range scale, Humboldt martens in California select the
largest available patch sizes of old-growth, old-growth and late-mature
(i.e., late-successional), and serpentine habitat (Slauson et al. 2007,
p. 466). Slauson et al. (2009b, p. 12) found that the biggest
difference between sites in California with stable Humboldt marten
occupancy versus unstable occupancy is patch size of old-growth forest,
with sites with more stable Humboldt marten occupancy associated with
larger patches of old-growth forest. The probability that a Humboldt
marten is detected increases as the following home range
characteristics increase in size: largest contiguous patch of late-
successional forest; total amount of late-successional forest; and
total area of serpentine habitat (Slauson 2003, p. 67). In non-
serpentine habitats, conifer-dominated, late-successional stands with
dense shrub cover in patches greater than or equal to 445 ac (180 ha)
are estimated to be a minimum criterion to identify potential Humboldt
marten home range areas (Slauson 2003, p. 70).
Compared to martens in the Sierra Nevada and Cascade mountains,
Humboldt martens occupy low-elevation areas with little or no snowfall
and select forest habitats with some distinctly different features,
such as dense, extensive shrub cover (Slauson et al. 2009b, p. 3).
Serpentine habitats occupied by Humboldt martens have open tree
canopies, dense shrub cover, and an abundance of boulder piles, while
non-serpentine sites have closed, multi-layered tree canopies, dense
shrub cover, and older age-class stands (Slauson 2003, p. 59).
Serpentine sites sometimes lack trees, suggesting that dense shrub
layers may provide the necessary overhead cover (Slauson 2003, pp. 60-
61). In addition, prey species, such as chipmunks (Tamias spp.) and
golden-mantled ground squirrels (Spermophilus lateralis), may use
boulder-sized surface rocks for escape cover in serpentine sites where
trees are sparse (Slauson 2003, p. 61). Recent Humboldt marten
population monitoring suggests that serpentine areas may represent
lower quality habitat than late-successional Douglas-fir forest
(Slauson et al. 2009b, p. 12). In non-serpentine habitats, Humboldt
martens use old-growth stands much more than expected based on
availability, use late-mature stands commensurate with availability,
and make little or no use of all other seral stages (Slauson et al.
2007, p. 462). All earlier seral stages are selected against, probably
because of the lack of one or more key structural features (Slauson
2003, p. 62). Dense shrub cover is the most consistent habitat feature
at sites selected by Humboldt martens in both serpentine and non-
serpentine habitats (Slauson et al. 2007, p. 465). Humboldt martens
show the strongest selection for conifer stands with greater than 80
percent shrub cover and select against stands with less than 60 percent
shrub cover (Slauson and Zielinski 2007b, p. 242). Plant species
dominating the shrub layers are shade-tolerant, long-lived, mast- and
berry-producing species, including salal (Gaultheria shallon),
evergreen huckleberry (Vaccinium ovatum), Pacific rhododendron
(Rhododendron macrophyllum), and shrub oaks (huckleberry oak (Quercus
vaccinifolia) and bush tanoak (Lithocarpus densiflorus var.
echinoides)) (Slauson and Zielinski 2009, p. 42). In contrast, Humboldt
martens do not use disturbance-associated species of shrubs, such as
Ceanothus spp. (Slauson and Zielinski 2009, p. 42). Dense stands of
mature shrubs provide refuge from predators, cover for prey species,
and mast (berries and acorns) for prey species and Humboldt martens,
and such stands may also deter larger-bodied competitors, such as
fisher and gray fox (Urocyon cinereoargenteus), by limiting their
foraging abilities (Slauson and Zielinski 2009, p. 42). Shrubs also
contribute to the formation of some resting locations and resting
structures (Slauson and Zielinski 2009, p. 42).
During the late summer and fall, Humboldt martens in California
used cavities, den chambers, and broken tops of standing dead trees for
87 percent of their resting locations, and branch platforms, ground
sites, and basal hollows for the remainder of their resting locations
(Slauson and Zielinski 2009, p. 39). Large snags were the most
frequently used resting structure with mean diameter-at-breast-height
(dbh) for conifers of 36.6 in (93 cm) (Slauson and Zielinski 2009, p.
40). Conifer logs used as resting structures had a mean diameter of
29.5 in (75 cm) (Slauson and Zielinski 2009, p. 40). Forty-two percent
of the resting structures used in serpentine habitats were located in
rock and shrub clumps (Slauson and Zielinski 2009, p. 40). All resting
sites in serpentine and non-serpentine habitats had dense shrub cover
(Slauson and Zielinski 2009, p. 42).
Availability of denning habitat is essential to successful
recruitment and persistence of American marten populations (Ruggiero et
al. 1998, p. 663). American marten natal dens, used by mothers and
neonatal young, are typically located in cavities in very large logs,
snags, or live trees, while maternal dens, used by mothers and older
but still dependent young, tend to be in less specialized structures
similar to resting sites (Ruggiero et al. 1998, p. 663). Slauson and
Zielinski (2009, p. 40) observed one adult female Humboldt marten with
a single kit at three maternal den structures: (1) A 26-in (66-cm) dbh
live chinquapin (Chrysolepis chrysophylla), (2) the broken top of a
44.5-in (113-cm) dbh live Douglas-fir, and (3) in a 45.3-in (115-cm)
dbh Douglas-fir snag.
Evaluation of Information for This Finding
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations at 50 CFR part 424 set forth the procedures for adding a
species to, or removing a species from, the Federal Lists of Endangered
and Threatened Wildlife and Plants. A species may be determined to be
an endangered or threatened species due to one or more of the five
factors described in section 4(a)(1) of the Act:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
In considering what factors might constitute threats, we must look
beyond the mere exposure of the species to the factor to determine
whether the species responds to the 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 how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species,
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such that the species may warrant listing as endangered or threatened
as those terms are defined by the Act. This does not necessarily
require empirical proof of a threat. The combination of exposure and
some corroborating evidence of how the species is likely impacted could
suffice. The mere identification of factors that could impact a species
negatively may not be sufficient to compel a finding that listing may
be warranted. The information must contain evidence sufficient to
suggest that these factors may be operative threats that act on the
species to the point that the species may meet the definition of
endangered or threatened under the Act.
In making this 90-day finding, we evaluated whether information
regarding threats to the Humboldt marten, as presented in the petition
and in other information available in our files, is substantial,
thereby indicating that the petitioned action may be warranted. Our
evaluation of this information is presented below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Habitat or Range
The petition states that the primary cause of population decline
and extirpation of martens in coastal northern California and coastal
Oregon is loss of old-growth coniferous forest habitat due to logging
(CBD and EPIC 2010, p. 20). According to the petition, logging
threatens Humboldt marten populations because martens require large
areas of unfragmented, old-growth forest to survive and because logging
reduces the amount of available habitat and key Humboldt marten habitat
structural elements, such as large standing and dead conifers, down
woody debris, and a dense understory of shade-tolerant shrubs (CBD and
EPIC 2010, pp. 20-23).
Zielinski et al. (2001, p. 487) postulated that timber harvest in
the redwood region was the most plausible reason for the continued
absence of Humboldt martens from most of the coastal range of
northwestern California. Zielinski et al. (2001, p. 487) concluded that
because martens typically are associated with old forests with a
diversity of large structural features, it is likely that the intensity
of timber harvest, especially on private lands, has reduced the habitat
value over much of the coastal northern California region. Large areas
of the Humboldt marten's range in California and Oregon are located on
private commercial timberlands (Zielinski et al. 2001, pp. 478, 484;
CBD and EPIC 2010, pp. 23, 32). Most of the areas within the Humboldt
marten's range in California and Oregon not located on private lands
are located on U.S. Forest Service (Forest Service) lands, but timber
harvesting occurs on most of these Forest Service lands (CBD and EPIC
2010, pp. 23, 29-32).
The petition also states that over the long-term, wildfire plays a
role in developing the habitat components on which martens depend, but
because the Humboldt marten's habitat has been so severely reduced by
logging, wildfires are now a threat to the subspecies (CBD and EPIC
2010, p. 24). Slauson and Zielinski (2004, p. 63) reported that, due to
the subspecies' critically low population size and restricted range in
northwestern California, fire threatens the Humboldt marten with short-
term loss and fragmentation of suitable habitat. Fires in 1998 and 2008
burned approximately 28 percent of the range currently occupied by
Humboldt marten in northwestern California (Service 2010, p. 19). The
Biscuit Fire, one of Oregon's largest fires in recorded history, burned
a total area of approximately 500,000 ac (202,343 ha) (Forest Service
2009), part of which overlapped the range of the southernmost
population of Humboldt marten in coastal Oregon. Fifty percent of the
total burn area burned very hot, with more than 75 percent of the
vegetation killed (Forest Service 2009). Post-fire site visits to some
of the areas burned in northwestern California in 2008 showed that the
dense shrub understory was removed, likely reducing the suitability and
increasing fragmentation of these areas for the Humboldt marten over
the short term (Slauson et al. 2009b, p. 11). In the cool, moist
coastal forests of northern California, fires pose a relatively low
risk to the Humboldt marten and its habitat. However, the habitat of
the current Humboldt marten population in northwestern California
occurs primarily in the relatively warm and dry Douglas-fir-tanoak
communities farther inland and at higher elevations and, thus, is more
vulnerable to lightning-ignited fires. Further, even low-intensity
fires can remove the dense shrub understory that is important to
Humboldt martens, reducing habitat quality and increasing fragmentation
of suitable habitat.
The petition states that recreational activities, including off-
highway vehicles, snowmobiles, dirt bikes, and camping could degrade
marten habitat, interfere with marten behavior, and cause martens to
shift to less suitable habitat (CBD and EPIC 2010, p. 24). The petition
recognizes that threats posed to Humboldt marten populations by
recreation are unknown, and that due to the remoteness of Humboldt
marten habitat and dense shrub cover preferred by the subspecies, the
threat posed by recreation is likely low (CBD and EPIC 2010, p. 25).
While certain recreational activities may have localized impacts on
marten habitat, information in the petition and in our files does not
indicate that recreational activities are having population-level
impacts that threaten the Humboldt marten.
Summary for Factor A
In summary, we find that the information provided in the petition,
as well as other information readily available in our files, presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted due to the present or threatened
destruction, modification, or curtailment of the Humboldt marten's
habitat or range from timber harvesting and fire. We will review the
possible effects of these threats to Humboldt marten more thoroughly in
our status review.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The petition states that historical trapping was the primary
contributor to the decline of martens in California, including the
portions of Humboldt, Del Norte, and Siskiyou Counties where the small
extant population of the Humboldt marten occurs (CBD and EPIC 2010, p.
25). In 1946, the California Fish and Game Commission closed the marten
trapping season in all or parts of Del Norte, Humboldt, Siskiyou, and
Trinity Counties due to declining harvests (Twining and Hensley 1947,
p. 136). However, Humboldt marten populations in coastal northern
California have not recovered, despite decades of protection from
trapping (Slauson and Zielinski 2004, p. 61).
While trapping of martens as furbearers in California is no longer
legal, the petition states that the threat posed to Humboldt martens by
accidental capture and poaching in California is magnified by other
threats such as small population size, population isolation, and
habitat fragmentation from logging and fire (CBD and EPIC 2010, p. 25).
In California, it is legal to trap other mammals that may occur in
Humboldt marten habitat, including bobcats and gray fox (California
Code of Regulations, Title 14, Sections 461 and 478), and Humboldt
martens may be captured incidentally in traps set for these species.
Body-gripping traps (such as steel-jawed leghold, padded leghold,
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conibear, and snares) were banned in California in 1998 (California
Fish and Game Code Section 3003.1). Only non-body-gripping traps, such
as cage and box live traps, are legal in California. No information was
provided in the petition, nor is any information available in our
files, to determine the extent of incidental trapping-related injury or
mortality from non-body-gripping traps. However, the use of box or cage
live traps suggests that, if trapped, Humboldt martens are more likely
to be released alive and unharmed than if body-gripping or other lethal
trap types were allowed. Due to the remote location of habitat occupied
by the Humboldt marten and the above restrictions, current mortalities
and injuries from incidental capture of Humboldt martens in
northwestern California are likely rare.
Additionally, current scientific survey techniques use nonlethal
methods, such as track-plates, camera stations, and live traps, and are
thus not likely to result in population-level impacts to the Humboldt
marten. While injury from accidental capture and poaching may affect
individual Humboldt martens in California, neither information in the
petition nor information in our files indicates that accidental capture
and poaching in California are likely to have a population-level effect
or threaten the Humboldt marten.
Martens are still legally trapped as furbearers in Oregon, and the
petition states that trapping remains a threat to martens in coastal
Oregon (CBD and EPIC 2010, p. 25). The petition states that the threat
posed to Humboldt martens by legal trapping in Oregon is magnified by
other threats such as small population size, population isolation, and
habitat fragmentation from logging and fire (CBD and EPIC 2010, p. 25).
Information in the petition indicates that martens can be trapped
throughout Oregon between November 1 and January 31 with the purchase
of a furtakers' license (CBD and EPIC 2010, p. 25). Although trapping
mortality of martens is a potential concern because marten populations
in coastal Oregon are considered small and isolated (see Population
Status section), most martens trapped in Oregon are taken from the
Cascade Range and Blue Mountains, and trapping harvest of martens in
the Oregon Coast Range is rare (Oregon Department of Fish and Wildlife
2010). We therefore conclude that information presented in the petition
and available in our files does not indicate that furbearer trapping in
Oregon is a threat to Humboldt marten.
Summary for Factor B
In summary, we find that the information provided in the petition,
as well as other information readily available in our files, does not
present substantial scientific or commercial information indicating
that the the petitioned action may be warranted due to overutilization.
However, we will review the possible effects of furbearer trapping in
Oregon on Humboldt marten more thoroughly in our status review.
C. Disease or Predation
Disease
The petition recognizes that disease in the Humboldt marten has not
been studied, but states that the Humboldt marten is potentially
threatened by disease given the subspecies' extremely small population
size (CBD and EPIC 2010, p. 26). Numerous pathogens are known to cause
severe disease in mustelids (Brown et al. 2008, pp. 5-6), but disease
exposure in the Humboldt marten has not been studied. Strickland et al.
(1982, p. 607) noted that American martens in their study area in
central Ontario, Canada, tested positive for toxoplasmosis, Aleutian
disease (a carnivore parvovirus), and leptospirosis; however, none of
these was known to be a significant mortality factor. Brown et al.
(2008) determined rates of pathogen exposure for the congeneric (member
of the same genus, Martes) fisher in northwestern California on the
Hoopa Valley Indian Reservation--located less than 6.2 mi (10 km) south
of the nearest Humboldt marten verified detection--and demonstrated
that fishers were exposed to several serious pathogens including canine
distemper virus, canine parvovirus, and West Nile virus. Of the 15
radio-collared fishers found dead on the Hoopa Valley Indian
Reservation during the pathogen study, 2 had been exposed to canine
distemper virus and 6 to canine parvovirus (Brown et al. 2008, p. 3).
Evidence of canine distemper virus infection has been reported in all
families of terrestrial carnivores, including the family Mustelidae
that includes martens and fishers (Deem et al. 2000, p. 441). In fact,
mustelids are among the species most susceptible to canine distemper
disease (Deem et al. 2000, p. 443). For example, black-footed ferrets
(Mustela nigripes) are highly susceptible to natural canine distemper
infection and have a fatality rate close to 100 percent (Bernard et al.
1984). Because canine distemper is highly contagious, and viral
shedding may follow infection for 60-90 days (Greene and Appel 1990),
it is reasonable to assume that infected fishers on the Hoopa Valley
Indian Reservation, especially dispersing juveniles, could infect the
nearby Humboldt marten population. Even at low exposure rates, canine
distemper has the potential to be a threat to one or more of the small
extant Humboldt marten populations.
Research cited in the petition and information in our files
indicates that fishers located in close proximity to Humboldt marten
occurrences in northwestern California have been exposed to canine
distemper, a disease that can be transmitted between different species
of carnivores and that can cause high levels of mortality in
carnivores, including species within the Mustelidae family. Estimated
size of the northwestern California Humboldt marten population is
small, so an outbreak of canine distemper or other lethal carnivore
disease could have a population-level impact and pose a threat to this
population.
Predation
The petition states that predation is a significant threat to the
Humboldt marten, especially because the subspecies is highly vulnerable
to mortality events and further population decline due to its small
population size (CBD and EPIC 2010, p. 25). Timber harvesting practices
that result in reduced shrub layers may result in increased
vulnerability of Humboldt martens to predation by larger carnivores,
such as fishers and gray foxes. Fishers and gray foxes typically occupy
forest types where shrub densities are naturally lower and are rarely
detected in coastal forest with extensive shrub cover (Slauson and
Zielinski 2007b, p. 242). Dense, spatially extensive shrub layers may
provide smaller-bodied Humboldt martens an advantage over other larger-
bodied carnivores (Slauson et al. 2007, p. 466), so that the removal of
these layers may put the Humboldt marten at risk of increased
predation. Although there may be associations between shrub cover and
risk of predation in forests where Humboldt martens occur, we did not
find information in the petition or in our files indicating that
elevated predation rates may be a threat to the continued existence of
Humboldt martens.
The petition states that recreational activities, including off-
highway vehicles, dirt bikes, hiking, and camping, could affect
Humboldt marten behavior, possibly exposing the Humboldt marten to
increased predation. The petition acknowledges that the level of the
threat from these recreational activities is unknown, but likely low
due to the remoteness of the
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currently occupied range of the Humboldt marten. We conclude that
information in the petition and information in our files does not
support the assertion in the petition that predation is a threat to
Humboldt marten.
Summary of Factor C
In summary, we find that the information provided in the petition,
as well as other information readily available in our files, presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted due to disease as a result of the
threat posed by canine distemper or other lethal carnivore diseases on
Humboldt marten. We will review the possible effects of these threats
to Humboldt marten more thoroughly in our status review.
D. The Inadequacy of Existing Regulatory Mechanisms
The petition states that existing regulatory mechanisms do not
adequately protect the Humboldt marten on Federal, State, tribal, or
private lands (CBD and EPIC 2010, pp. 28-33). The petition further
states that martens are still legally trapped in coastal Oregon and
that existing regulatory mechanisms are inadequate to protect habitat
for the martens in coastal northern California and coastal Oregon (CBD
and EPIC 2010, p. 28).
The petition states that large areas of the Humboldt marten's
historical range and current range occur on privately owned commercial
timberlands where existing regulatory mechanisms do not protect
Humboldt martens from habitat loss and degradation due to timber
harvesting (CBD and EPIC 2010, p. 29). As mentioned in the Factor A
section above, large areas of the Humboldt marten's current range in
coastal northern California and coastal Oregon occur on private
commercial timberland. Information in our files supports the assertion
that forest management practices on these private commercial
timberlands may not be compatible with habitat management for martens
(see Factor A; Zielinski et al. 2001, pp. 483-488).
The petition also states that existing regulatory mechanisms on
Federal Forest Service lands are not adequate to protect Humboldt
martens from habitat loss and degradation due to timber harvesting (CBD
and EPIC 2010, pp. 28-29). The petition acknowledges that the American
marten is recognized as a Forest Service sensitive species in
California, but not in Oregon (CBD and EPIC 2010, p. 29); however, the
petition goes on to state that the sensitive species status in
California does not provide nondiscretionary protections and thus is
not considered an adequate regulatory mechanism (CBD and EPIC 2010, p.
29). The petition also states that large areas of the Humboldt marten's
current range on Forest Service lands are designated as matrix lands
under the Northwest Forest Plan (NWFP), and that timber harvesting that
may be incompatible with Humboldt marten habitat management is allowed
on matrix lands (CBD and EPIC 2010, pp. 29-30). The NWFP was adopted in
1994 to guide the management of 37,500 sq mi (97,125 sq km) of Federal
lands in portions of western Washington and Oregon, and northwestern
California. Implementation of the NWFP was intended to provide, over
time, a network of large blocks of late-successional forest habitat
connected by riparian reserves. However, even with NWFP implementation,
timber harvest, fuels reduction projects, and road construction may
continue to result in the loss and fragmentation of occupied and
suitable but unoccupied Humboldt marten habitat throughout a
substantial portion of its range in coastal Oregon and northwestern
California. Protections for late-successional forest habitats provided
for species such as the northern spotted owl (Strix occidentalis
caurina) and marbled murrelet (Brachyramphus marmoratus), which are
listed as threatened under the Act, provide certain protections for
marten habitat but may not provide sufficient protections for certain
habitat elements known to be important for Humboldt martens, such as
shade-tolerant shrub cover.
Summary of Factor D
In summary, we find that the information provided in the petition,
as well as other information readily available in our files, presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted due to the inadequacy of existing
regulatory mechanisms that address habitat threats associated with
timber harvesting and forest management. We will review the possible
effects of these threats on Humboldt marten more thoroughly in our
status review.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
The petition states that several other factors threaten the
continued existence of the Humboldt marten, including small population
size effects; mortality from vehicle strikes, poisoning, and
starvation; and global climate change (CBD and EPIC 2010, pp. 27-28).
The petition states that widespread timber harvesting has resulted
in drastically reduced suitable habitat for Humboldt marten, and that
existing populations in California and coastal Oregon are small and
isolated (CBD and EPIC 2010, p. 27). The smaller a population becomes,
the more susceptible it is to stochastic (random) demographic and
environmental variation and to genetic factors that tend to reduce
population size even more and that may push the population to
extinction (Primack 1993, p. 274). Primack (1993, p. 335) found that
population size was the best predictor of extinction probability.
Slauson et al. (2009b, p. 5) used multi-season occupancy modeling to
estimate the probability of extinction and colonization (probability
that Humboldt martens in northwestern California would reoccupy
currently unoccupied suitable habitat) and found that the probability
of extinction was higher than the probability of colonization (Slauson
et al. 2009b, p. 10). As mentioned in the Species Information section,
for a mammal of its size, American martens--and presumably Humboldt
martens--have a relatively low reproductive rate, suggesting a slow
recovery from population-level impacts. Species with low rates of
population increase are often unable to rebuild their populations fast
enough to avoid extinction following habitat loss (Primack 1993, p.
102). As mentioned in the Population Status section, it is estimated
that the extant Humboldt marten population in coastal northern
California contains fewer than 100 individuals and is believed to be
declining, and the two coastal Oregon populations are also considered
to be small and in decline. Information in our files supports the
assertion in the petition that current Humboldt marten populations in
coastal northern California and coastal Oregon are vulnerable to
extinction processes due to small and isolated populations (Slauson et
al. 2007, p. 458; Slauson et al. 2009b, p. 13).
The petition states that the Humboldt marten is threatened by
several sources of mortality including vehicle strikes, poisoning, and
starvation (CBD and EPIC 2010, p. 28). Zielinski et al. (2001, p. 484)
noted that 10 marten road kills had been reported from coastal central
Oregon between 1980 and 1998, while no marten road kills had been
reported in coastal California. We acknowledge that Humboldt martens
are occasionally killed by vehicles along highways, but we do not
consider the numbers reported by Zielinski et al. (2001, p.
[[Page 1908]]
484) to be sufficiently great to threaten the continued existence of
the Humboldt marten, nor do we have information in our files indicating
that mortality from vehicle collisions threatens martens in coastal
northern California and coastal Oregon. The petition also states that
martens are vulnerable to mortality from starvation and poisoning,
although the petition acknowledges that the extent of the threat of
these factors to the Humboldt marten has not been quantified (CBD and
EPIC 2010, p. 28). We conclude that information in the petition and in
our files does not indicate that mortality from poisoning or starvation
threatens the continued existence of martens in coastal northern
California and coastal Oregon. However, we will evaluate these
potential threats more thoroughly in our 12-month finding.
The petition further states that global climate change threatens
the Humboldt marten (CBD and EPIC 2010, p. 28). According to the
petition, vegetation changes resulting from climate change could cause
changes in the type and availability of prey for martens and could
affect availability of resting and denning sites, shrub cover, and
canopy cover. The petition also states that climate change could lead
to tree mortality from insect infestation, disease, and drought. While
we acknowledge that climate change will result in a variety of
environmental changes including changes in vegetation composition and
structure, information presented in the petition is too general and
speculative to determine whether climate change effects may threaten
the continued existence of the Humboldt marten, and we do not have
specific information available in our files indicating that climate
change threatens the continued existence of the Humboldt marten.
Summary of Factor E
In summary, we find that the information provided in the petition,
as well as other information readily available in our files, presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted due to other natural or manmade
factors affecting its continued existence, specifically small
population effects. We will review threats posed by small population
effects more thoroughly during our status review.
Finding
On the basis of our determination under section 4(b)(3)(A) of the
Act, we determine that the petition presents substantial scientific or
commercial information indicating that listing the Humboldt marten
throughout all or a significant portion of its range may be warranted.
This finding is based on substantial information provided in the
petition and in our files for Factor A, Factor C, Factor D, and Factor
E. We determine that the information provided under Factor B is not
substantial.
Because we have found that the petition presents substantial
information indicating that listing the Humboldt marten may be
warranted, we are initiating a status review to determine whether
listing the Humboldt marten under the Act is warranted. Because ongoing
genetics research may result in changes to American marten taxonomy, we
will examine whether the purported subspecific designation of Humboldt
marten is appropriate during our status review. If the Humboldt marten
does not maintain its status as a subspecies, we will examine during
our status review whether the Humboldt marten meets criteria for
designation as a distinct population segment under our February 7,
1996, DPS policy (61 FR 4722).
The ``substantial information'' standard for a 90-day finding
differs from the Act's ``best scientific and commercial data'' standard
that applies to a status review to determine whether a petitioned
action is warranted. A 90-day finding does not constitute a status
review under the Act. In a 12-month finding, we will determine whether
a petitioned action is warranted after we have completed a thorough
status review of the species, which is conducted following a
substantial 90-day finding. Because the Act's standards for 90-day and
12-month findings are different, as described above, a substantial 90-
day finding does not mean that the 12-month finding will result in a
warranted finding.
References Cited
A complete list of references cited is available on the Internet at
https://www.regulations.gov and upon request from the Arcata Fish and
Wildlife Office (see FOR FURTHER INFORMATION CONTACT section).
Authors
The primary authors of this document are the staff members of the
Arcata Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT
section).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: December 30, 2011.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2012-479 Filed 1-11-12; 8:45 am]
BILLING CODE 4310-55-P
