Endangered and Threatened Wildlife and Plants; Emergency Rule To List the Columbia Basin Distinct Population Segment of the Pygmy Rabbit (Brachylagus idahoensis) as Endangered

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: November 30, 2001 (Volume 66, Number 231)]
[Rules and Regulations]
[Page 59734-59749]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30no01-28]

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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1080-AI17

Endangered and Threatened Wildlife and Plants; Emergency Rule To
List the Columbia Basin Distinct Population Segment of the Pygmy Rabbit
(Brachylagus idahoensis) as Endangered

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Emergency rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), exercise our
authority under the Endangered Species Act of 1973, as amended (Act),
to emergency list the Columbia Basin distinct population segment of the
pygmy rabbit (Brachylagus idahoensis) as endangered. This population
segment consists of a single, wild colony totaling fewer than 50
individuals in Douglas County, central Washington, and a small captive
population.
The Columbia Basin pygmy rabbit is imminently threatened by a
recent significant decrease in population that has caused it to be
susceptible to the combined influence of catastrophic environmental
events, habitat or resource failure, disease, predation, and loss of
genetic heterogeneity. We find that these threats constitute an
immediate and significant risk to the well-being of the Columbia Basin
pygmy rabbit. Because of the need to make protective measures afforded
by the Act immediately available to this species, we find that an
emergency rule action is justified. This emergency rule provides
Federal protection pursuant to the Act for a period of 240 days. A
proposed rule to list the Columbia Basin pygmy rabbit as endangered is
published concurrently with this emergency rule in the proposed rule
section of this issue of the Federal Register.

DATES: This emergency rule becomes effective immediately on November
30, 2001, and expires July 29, 2002.

ADDRESSES: The complete file for this emergency rule is available for
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Upper Columbia Fish and Wildlife Office,
11103 East Montgomery Drive, Spokane, Washington 99206.

FOR FURTHER INFORMATION CONTACT: Christopher Warren at the address
listed above (telephone 509/891-6839; facsimile 509/891-6748;
electronic mail: chris_warren@fws.gov).

SUPPLEMENTARY INFORMATION:

Background

The pygmy rabbit (Brachylagus idahoensis) is a member of the family
Leporidae, which includes hares and rabbits. The species has been
placed in a number of genera since it was first described in 1891
(Washington Department of Fish and Wildlife (WDFW) 1995), when it was
classified as Lepus idahoensis. In 1904, it was reclassified and placed
in the genus Brachylagus, and in 1930, it was again reclassified and
placed in the genus Sylvilagus (WDFW 1995). More recent examination of
dentition (Hibbard 1963) and analysis of blood proteins (Johnson 1968)
suggests that the pygmy rabbit differs significantly from species
within either the Lepus or Sylvilagus genera. The pygmy rabbit is now
generally considered to be within the monotypic genus Brachylagus, and
again classified as B. idahoensis (Green and Flinders 1980a; WDFW
1995). There are no recognized subspecies of the pygmy rabbit (Dalquest
1948; Green and Flinders 1980a).
The pygmy rabbit is the smallest Leporid in North America, with
mean adult weights from 375 to 462 grams (0.83 to 1.02 pounds), and
lengths from 23.5 to 29.5 centimeters (cm) (9.3 to 11.6 inches (in))
(Orr 1940; Janson 1946; Wilde 1978; Gahr 1993; WDFW 1995). Females tend
to be slightly larger than males. The overall color of pygmy rabbits is
slate-gray tipped with brown. Their legs, chest, and nape are tawny
cinnamon-brown, their bellies are whitish, and the entire edges of
their ears are pale buff. Their ears are short (3.5 to 5.2 cm (1.4 to
2.0 in)), rounded, and thickly furred inside and out. Their tails are
small (1.5 to 2.4 cm (0.6 to 0.9 in)), uniform in color, and nearly
unnoticeable in the wild (Orr 1940; Janson 1946; WDFW 1995). The pygmy
rabbit is distinguishable from other Leporids by its small size, short
ears, gray color, small hind legs, and lack of white on the tail.
Pygmy rabbits typically are found in areas of tall, dense sagebrush
(Artemisia spp.) cover, and are highly dependent on sagebrush to
provide both food and shelter throughout the year (Orr 1940; Green and
Flinders 1980a; WDFW 1995). The winter diet of pygmy rabbits is
composed of up to 99 percent sagebrush (Wilde 1978), which is unique
among Leporids (White et al. 1982). During spring and summer, their
diet consists of roughly 51 percent sagebrush, 39 percent grasses
(particularly native bunch-grasses, such as Agropyron spp. and Poa
spp.), and 10 percent forbs (Green and Flinders 1980b). There is
evidence that pygmy rabbits preferentially select native grasses as
forage during this period in comparison to other available foods. In
addition, total grass cover relative to forbs and shrubs may be reduced
within pygmy rabbit colonies as a result of its use as a food source
during spring and summer (Green and Flinders 1980b).
The pygmy rabbit is believed to be one of only two Leporids in
North America that digs its own burrows (Nelson 1909; Green and
Flinders 1980a; WDFW 1995), the other being the volcano rabbit
(Romerolagus diazi) found in central Mexico (Durrell and Mallinson
1970). Pygmy rabbit burrows typically are found in relatively deep,
loose soils of wind-borne (i.e., loess) or water-borne (e.g., alluvial
fan) origin. Pygmy rabbits occasionally make use of burrows abandoned
by other species, such as the yellow-bellied marmot (Marmota
flaviventris) or badger (Taxida taxus) (Wilde 1978; Green and Flinders
1980a; WDFW 1995) and may occur in areas of shallower or more compact
soils that support sufficient shrub cover (Bradfield 1974). During
winter, pygmy rabbits make extensive use of snow burrows to access
sagebrush forage (Bradfield 1974; Katzner and Parker 1997).
Pygmy rabbits, especially juveniles, likely use their burrows as
protection from predators and inclement weather (Bailey 1936; Bradfield
1974). The burrows frequently have multiple entrances, some of which
are concealed at the base of larger sagebrush plants (WDFW 1995).
Burrows are relatively simple and shallow, often no more than 2 meters
(m) (6.6 feet (ft)) in length and usually less than 1 m (3.3 ft) deep
with no distinct chambers (Bradfield 1974; Green and Flinders 1980a;
Gahr 1993). Burrows typically are dug into gentle slopes or mound/
inter-mound areas of more level or dissected topography (Wilde 1978;
Kehne 1991; Gahr 1993). In general, the number of active burrows in a
colony increases over the summer as the number of juveniles increases.
However, the number of active burrows may not be directly related to
the number of individuals in a given colony because some individual
pygmy rabbits appear to maintain multiple burrows, while some
individual burrows are used by multiple individuals (Gahr 1993; WDFW
1995).
Pygmy rabbits begin breeding in their second year and, in
Washington, breeding occurs from February through July (WDFW 1995).
Females may have up to three litters per year and average six young per
litter (Green 1978; Wilde

[[Page 59735]]

1978). Breeding appears to be highly synchronous in a colony, and
juveniles are often identifiable to cohorts (Wilde 1978). No evidence
of nests, nesting material, or lactating females with young has been
found in burrows (Bradfield 1974; Gahr 1993; WDFW 1995). Individual
juveniles have been found under clumps of sagebrush, although it is not
known precisely where the young are born in the wild or if they may be
routinely hidden at the bases of scattered shrubs or within burrows
(Wilde 1978).
Recent information on captive pygmy rabbits indicates that females
may excavate specialized ``natal'' burrows for their litters in the
vicinity of their regular burrows (P. Swenson, Oregon Zoo, pers. comm.,
2001; L. Shipley, Washington State University (WSU), pers. comm.,
2001). Apparently, females begin to dig and supply nesting material
(e.g., grass clippings) to these burrows several days prior to giving
birth and may give birth and nurse their young at the ground surface in
a small depression near the burrow's entrance. After nursing, the young
return to the burrow and the female refills the burrow entrance with
loose soil and otherwise disguises the immediate area to avoid
detection. Other ``dead-end'' burrows that females construct nearby
apparently are associated with the natal burrows. Females may also
alter their defecation and latrine habits while pregnant and nursing
(P. Swenson, pers. comm., 2001). Further work with captive and wild
pygmy rabbits should shed additional light on the details of their
reproductive strategy.
Pygmy rabbits may be active at any time of the day or night and
appear to be most active during mid-morning (Bradfield 1974; Green and
Flinders1980a; Gahr 1993). Pygmy rabbits maintain a low stance, have a
deliberate gait, and are relatively slow and vulnerable in more open
areas. They can evade predators by maneuvering through the dense shrub
cover of their preferred habitats, often along established trails, or
by escaping into their burrows (Bailey 1936; Severaid 1950; Bradfield
1974).
Pygmy rabbits tend to have relatively small home ranges during
winter, remaining within roughly 30 m (98 ft) of their burrows (Orr
1940; Janson 1946; Gahr 1993; Katzner and Parker 1997), although some
snow burrows may extend outward up to 100 m (328 ft) (Bradfield 1974).
They have larger home ranges during spring and summer (Orr 1940; Janson
1946; Gahr 1993; Katzner and Parker 1997). During the breeding season
in Washington, females tend to make relatively short movements within a
small core area and have home ranges covering roughly 2.7 hectares (ha)
(6.7 acres (ac)); males tend to make longer movements, traveling among
a number of females, resulting in home ranges covering roughly 20.2 ha
(49.9 ac) (Gahr 1993). These home range estimates in Washington are
considerably larger than for pygmy rabbit populations in other areas of
their historic range (WDFW 1995; Katzner and Parker 1997). Pygmy
rabbits may travel up to 1.2 kilometers (km) (0.75 miles (mi)) from
their burrows (Gahr 1993), and there are a few records of apparently
dispersing individuals moving up to 3.5 km (2.17 mi) (Green and
Flinders 1979; Katzner and Parker 1998).
The annual mortality rate of adult pygmy rabbits may be as high as
88 percent, while over 50 percent of juveniles apparently die within
roughly 5 weeks of their emergence (Wilde 1978; WDFW 1995). However,
the mortality rates of adult and juvenile pygmy rabbits can vary
considerably between years, and even between juvenile cohorts within
years (Wilde 1978). Predation is the main cause of pygmy rabbit
mortality (Green 1979). Potential predators include badgers (Taxidea
taxus), long-tailed weasels (Mustela frenata), coyotes (Canis latrans),
bobcats (Felis rufus), great horned owls (Bubo virginianus), long-eared
owls (Asio otus), ferruginous hawks (Buteo regalis), and northern
harriers (Circus cyaneus) (Janson 1946; Gashwiler et al. 1960; Green
1978; Wilde 1978; WDFW 1995).
Population cycles are not known in pygmy rabbits, although local,
relatively rapid population declines have been noted in several States
(Bradfield 1974; Weiss and Verts 1984; WDFW 1995). After initial
declines, pygmy rabbit populations may not have the same capacity for
rapid increases in numbers as other Leporids due to their close
association with specific components of sagebrush ecosystems (Wilde
1978; Green and Flinders 1980b; WDFW 1995).

Distribution and Status

The historic distribution of the pygmy rabbit included much of the
semi-arid, shrub steppe region of the Great Basin and adjacent
intermountain zones of the conterminous western United States (Green
and Flinders 1980a), and likely included portions of Montana, Idaho,
Wyoming, Utah, Nevada, California, Oregon, and Washington (Figure 1).
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Currently, pygmy rabbits are not distributed continuously across
their range, nor were they historically. Rather, they are found in
areas within their broader distribution where sagebrush cover is
sufficiently tall and dense, and where soils are sufficiently deep and
loose to allow burrowing (Bailey 1936; Green and Flinders 1980a; Weiss
and Verts 1984; WDFW 1995). The local distribution of these habitat
patches, and thus pygmy rabbits, likely shifts across the landscape in
response to various sources of disturbance (e.g., fire, flooding,
grazing, and crop production) combined with long- and short-term
weather patterns. Historically, more dense vegetation along permanent
and intermittent stream corridors, alluvial fans, and sagebrush plains
probably provided travel corridors or dispersal habitat for pygmy
rabbits between appropriate use areas (Green and Flinders 1980a; Weiss
and Verts 1984; WDFW 1995). Since European settlement of the western
United States, more dense vegetation associated with human activities
(e.g., fence rows, roadway shoulders, crop margins, and abandoned
fields) also may have acted as avenues of dispersal between local
populations of pygmy rabbits (Green and Flinders 1980a; Pritchett et
al. 1987).

Prehistoric Distribution

The population segment of the pygmy rabbit within the Columbia
Basin, a geographic area that extends from northern Oregon through
eastern Washington (Quigley et al. 1997), is believed to have been
disjunct from the remainder of the species' range since at least the
early Holocene (10,000 to 7,000 years before present (BP)), as
suggested by fossil records (Grayson 1987; Lyman 1991). This separation
is in contrast to the relatively short-term, local patterns of
isolation, extirpation, and recolonization that likely occur throughout
pygmy rabbit range (above). The pygmy rabbit has been present in the
Columbia Basin for at least 100,000 years and had a broader
distribution during the mid-Holocene (roughly 7,000 to 3,000 years BP)
(Lyman 1991). Gradual climate change affecting the distribution and
composition of sagebrush communities is thought to have resulted in a
reduction of pygmy rabbit range within the Columbia Basin during the
late Holocene (3,000 years BP to present) (Grayson 1987; Lyman 1991).

Historic and Current Distribution

Pygmy rabbits have been considered rare for many years, with local
areas of occurrence in Washington (Dalquest 1948), although there is
little comprehensive information available regarding their historic
distribution and abundance in the State (WDFW 1995). Museum specimens
and reliable sight records indicate that, during the first half of the
1900s, pygmy rabbits probably occurred in at least five Washington
counties, including Douglas, Grant, Lincoln, Adams, and Benton (Figure
2). Once thought to be extirpated from the State, pygmy rabbits were
again located in Washington in 1979. Intensive surveys in 1987 and 1988
discovered five small colonies of pygmy rabbits in southern Douglas
County; three occurred on State lands and two on private lands (WDFW
1995). With the exception of a single site record from Benton County in
1979, pygmy rabbits have been found only in southern Douglas and
northern Grant Counties since 1956 (WDFW 2000a). The Washington
Wildlife Commission designated the pygmy rabbit as a State threatened
species in 1990 and reclassified it as endangered in 1993 (WDFW 1995).
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The number of pygmy rabbit colonies and active burrows in
Washington has declined over the past decade (WDFW 2001a). Four of the
five colonies located in 1987 and 1988 were very small, with fewer than
100 active burrows (WDFW 1995); the largest colony (at the State-owned
Sagebrush Flat site in Douglas County) contained roughly 588 active
burrows in 1993, when it was estimated to support fewer than 150
rabbits (Gahr 1993). While an additional colony was discovered on
private land in northern Grant County in 1997, three of the small
colonies originally located became extirpated during the 1990s, leaving
just three known colonies in 1999 (WDFW 2001a).
One of the three remaining sites experienced a catastrophic fire in
1999 and declined to three active burrows, while the newly discovered
site declined for unknown reasons to two active burrows following the
winter of 1999-2000 (WDFW 2001a). These two colonies are now thought to
be extirpated (WDFW 2001b; D. Hays and T. McCall, WDFW, pers. comm.,
2001). In addition, during the winter of 1997-1998, the number of
active pygmy rabbit burrows at Sagebrush Flat declined by approximately
50 percent, and has continued to decline each year since (WDFW 2001a).
The entire wild pygmy rabbit population in Washington is now considered
to consist of fewer than 50 individuals, possibly from just one known
colony at Sagebrush Flat in Douglas County (T. McCall, pers. comm.,
2001).
Although habitat loss and fragmentation likely have played a
primary role in the long-term prehistoric and historic decline of the
pygmy rabbit in Washington, it is unlikely that these factors have
directly influenced the post-1995 declines at Sagebrush Flat and the
extirpations of some of the smaller populations (WDFW 2001a). Once
populations decrease below a certain threshold, they become at risk of
extirpation from a number of sources, including disease, predation,
catastrophic event (e.g., fire), and random environmental events (e.g.
extreme weather) (WDFW 2001a). The remaining wild population of pygmy
rabbits in Washington is currently at such risk and without immediate
intervention, it likely will become extirpated within the near future.

Previous Federal Action

We added the pygmy rabbit to our candidate species list on November
21, 1991, as a category 2 species (56 FR 58804). A category 2 species
was one for which we possessed information indicating that a proposal
to list it as threatened or endangered under the Act was possibly
appropriate, but for which conclusive data on biological vulnerability
and threats was not available to support a proposed rule. On February
28, 1996, we discontinued the designation of category 2 species as
candidates for listing under the Act (61 FR 7596). Species that were
formerly category 2 candidates currently are watched, managed, and
protected by the States they occupy and by the Service field offices in
those States, but have no Federal regulatory status. We are currently
planning a status review of the pygmy rabbit range-wide to determine if
further Federal regulatory protection for the species is appropriate.
The processing of this emergency rule conforms with our updated
Listing Priority Guidance, published in the Federal Register on October
22, 1999 (64 FR 57114). The guidance clarifies the order in which we
process rule-makings. Highest priority is given to processing emergency
listing rules for any species determined to face a significant risk to
its well-being. Second priority is the processing of final
determinations on proposed additions to the lists of endangered and
threatened wildlife and plants. Third priority is processing new
proposals to add species to the lists. The processing of administrative
petition findings (petitions filed under section 4 of the Act) is the
fourth priority.

Current Management Actions

The WDFW has undertaken a variety of conservation actions for pygmy
rabbits in Washington since 1979 (WDFW 1995; WDFW 2001a). These actions
have included population surveys, habitat inventories, land
acquisitions, habitat restoration, land management agreements,
initiation of studies on the effects of grazing, and emergency predator
control. Some of these efforts have been partially funded by the
Bonneville Power Administration. As funding sources and staffing levels
allow, WDFW efforts to conserve pygmy rabbits in the wild will continue
(D. Hays, pers. comm., 2001).
During the fall of 2000, in cooperation with the Oregon Zoo, the
WDFW initiated a study of husbandry techniques for pygmy rabbits (WDFW
2001a). This study used five pygmy rabbits captured in Idaho and was
undertaken to improve the information base for proposed captive rearing
and release efforts for Washington's pygmy rabbits. Due to the
continuing decline of pygmy rabbit colonies and active burrows in
Washington, the WDFW, in cooperation with WSU, expedited their captive
rearing efforts for pygmy rabbits in Washington during the spring of
2001 (WDFW 2001b; D. Hays, pers. comm., 2001).
The immediate goal of the effort for pygmy rabbits in Washington is
to capture up to 20 animals to establish a captive breeding stock. The
actual number and type (gender, age, family unit) of pygmy rabbits
taken from the wild will be based partly on information from the
ongoing husbandry study, and partly on estimates of what is needed to
allow for appropriate manipulation of genetic lineages to better manage
this population's unique genetic profile. Pygmy rabbits that are not
considered essential to the captive rearing effort will be left in the
wild, and ongoing management to protect this wild portion of the
population will continue.
During the spring and early summer of 2001, eleven pygmy rabbits
(seven female, four male) were captured from the Washington population
as an initial source for captive breeding efforts (D. Hays, pers.
comm., 2001). One male subsequently died, and the cause of its death is
being investigated. The ten remaining rabbits appear to have adjusted
well to the captive-rearing facilities and reproductive behavior has
been observed, including the birth of a litter of five offspring (two
female, three male) that was conceived in the wild (L. Shipley, pers.
comm., 2001; D. Hays, pers. comm., 2001). The intent is to capture
additional animals this year that will complement the genetic profiles
and potential breeding scenarios of those already in captivity (D.
Hays, pers. comm., 2001).
Ultimately, the goal of the captive rearing effort is to release
Washington's pygmy rabbits back into wild habitats within the State
where viable colonies can become re-established and the wild population
can be recovered (WDFW 2001b; D. Hays, pers. comm., 2001). The number
and size of the wild colonies necessary for recovery is yet to be
determined. Pygmy rabbits within captive propagation facilities will
not be counted toward recovery of the species; the captive propagation
program affords an opportunity to protect and maintain the Columbia
Basin pygmy rabbit until environmental conditions become more favorable
to the survival of the species in the wild through natural cycles and
as a result of habitat protection and enhancement. The timing and
objectives for the release phase of the program will be further
developed as the captive-rearing effort becomes established. The WDFW
will remain the lead agency for these efforts, and has developed a
Science Advisory Group to provide recommendations and technical
oversight for the conservation program.

[[Page 59740]]

The group currently comprises State and Federal agency personnel,
public zoo and university experts, representatives from non-
governmental organizations, and private individuals with interests in
the conservation of Washington's pygmy rabbits.
The Nature Conservancy (TNC), a non-governmental natural resource
advocacy organization, has acquired, or obtained easements on, portions
of the remaining shrub steppe habitat in southern Douglas and northern
Grant Counties, including a recent acquisition of approximately 6,900
ha (17,000 ac) adjacent to the WDFW's Sagebrush Flat site. As
appropriate, TNC lands in central Washington will be managed to support
the conservation efforts for pygmy rabbits (C. Warner, TNC, pers.
comm., 2001).
Portions of the remaining shrub steppe habitat in southern Douglas
and northern Grant Counties are under the jurisdiction of the U.S.
Bureau of Land Management (BLM) and the Washington Department of
Natural Resources. Conservation measures for pygmy rabbits are also
considered in the management of these agency lands (N. Hedges, BLM,
pers. comm., 2001; D. Hays, pers. comm., 2001). Many of the existing
and future land acquisitions and management actions of the TNC, BLM,
and State agencies in this area are targeted at sites recently used by
pygmy rabbits and at providing connectivity of appropriate habitats
between these sites.
Large areas of privately owned lands in Douglas County are
currently withdrawn from crop production and, under the 1985 Federal
Conservation Reserve Program (CRP) (U.S. Department of Agriculture
1998), are planted to native and non-native vegetation. These lands,
some of which have been set aside since the late 1980s, provide grass
and shrub cover that may improve the habitat conditions of areas
potentially occupied or used as dispersal corridors by pygmy rabbits.
New and re-signed program contracts completed in 1998 increased the
acreage of CRP lands in Douglas County. However, contracts extend for
just 10 years and new standards for CRP lands are being implemented
that require replanting of significant acreage under existing contracts
(USDA 1998; Schroeder, WDFW, pers. comm., 2001). Presently, it is
unclear what effects the CRP lands and recent changes to the program
may have on pygmy rabbits in Washington.
Currently, we are assisting private landowners and their
conservation districts with development of a county-wide Habitat
Conservation Plan (HCP) for agricultural lands in Douglas County,
Washington. When completed, the Foster Creek HCP will include measures
to protect pygmy rabbits and will complement other, ongoing
conservation efforts in Douglas County.

Distinct Vertebrate Population Segment

Pursuant to the Act, we must consider for listing any species,
subspecies, or, for vertebrates, any distinct population segment (DPS)
of these taxa if there is sufficient information to indicate that such
action may be warranted. To implement the measures prescribed by the
Act and Congressional guidance, the Service and National Marine
Fisheries Service developed a joint policy in 1996 that addresses the
recognition of DPSs for potential listing actions (61 FR 4722). The
policy allows for more refined application of the Act that better
reflects the biological needs of the taxon being considered, and avoids
the inclusion of entities that do not require its protective measures.
Under our DPS policy, three elements are considered in a decision
regarding the status of a possible DPS as endangered or threatened
under the Act. Two of these elements are used to assess whether a
population segment under consideration for listing constitutes a DPS;
these elements are (1) the population segment's discreteness from the
remainder of the taxon, and (2) the population segment's significance
to the taxon to which it belongs. A systematic application of the above
elements is appropriate, with discreteness criteria applied first,
followed by significance analysis. If we determine that a population
segment being considered for listing represents a DPS, then the third
element, the status of the population in relation to the Act's
standards for listing (i.e., is the population segment, when treated as
if it were a species, endangered or threatened), is evaluated based on
the five listing factors established by the Act.

Discreteness

Discreteness may be demonstrated by either, or both, of the
following: (1) Physical, physiological, ecological, behavioral,
morphological, or genetic discontinuity between population segments, or
(2) international governmental boundaries between which differences in
regulatory mechanisms exist that are significant with regard to
conservation of the taxon. The pygmy rabbit does not occur outside of
the lower 48 conterminous United States and, therefore, the
international boundary criterion does not apply to this emergency rule.
The population segment of the pygmy rabbit occupying the Columbia
Basin has been physically discrete from the remainder of the taxon for
several millennia (see Distribution and Status, above). In addition,
there is recent evidence that the Columbia Basin population segment is
ecologically and genetically discrete from the remainder of the taxon
(see Significance, below). Based on this information, we find that the
population segment of the pygmy rabbit within the Columbia Basin is
discrete from the remainder of the taxon pursuant to the Act. Behavior,
morphological, or physiological differences between pygmy rabbits of
the Columbia Basin DPS and those from the remainder of the range are
not known at this time, but given the genetic distinction and length of
temporal separation, such differences would not be considered
anomalous.

Significance

Our DPS policy provides several examples of the types of
information that may demonstrate the significance of a discrete
population segment to the remainder of its taxon, including, but not
limited to (1) persistence of the population segment in an ecological
setting unusual or unique for the taxon; (2) evidence that the
population segment differs markedly from other population segments in
its genetic characteristics; and (3) evidence that loss of the
population segment would result in a significant gap in the range of
the taxon. The following significance factors, presented in order of
their significance, have bearing on the population segment of the pygmy
rabbit that remains in central Washington.
Markedly different genetic characteristics. Several studies have
been initiated to investigate the pygmy rabbit's genetic profile (WDFW
2000c; WDFW 2001a; Cegelski and Waits, undated). To date, the genetics
analyses include recent (c. 1990 to present) samples from Washington,
Idaho, and Montana, and museum specimens (c. 1900s to 1970s) from
Washington, Montana, Idaho, Oregon, with a median date of 1949 (K.
Warheit, WDFW, pers. comm., 2001; WDFW 2001c). Analyses have included
both mitochondrial DNA and nuclear DNA markers (WDFW 2001c).
Results from recent genetic analyses indicate that the Washington
population of the pygmy rabbit (the Columbia Basin population segment)
is distinct and only distantly related to the other pygmy rabbit
populations (WDFW 2001c; K. Warheit, pers. comm., 2001). In analyses of
both mitochondrial and nuclear DNA indices, a single haplotype found to
be

[[Page 59741]]

present in Washington pygmy rabbits was also found to be distinct from
the three haplotypes shared by Oregon, Idaho, and Montana pygmy
rabbits. These differences are consistent between recent (WA versus ID
and MT) and museum (WA versus OR, ID, and MT) samples. The data also
indicate that the Washington pygmy rabbit population diverged (i.e.,
was genetically isolated) from the Montana and Idaho populations
approximately 40,000 to 115,000 years ago, although a more conservative
estimate would indicate 10,000 to 25,000 years of isolation (WDFW
2001c). These genetic differences more likely than not are similar to
subspecific differences recognized in other mammals; exact taxonomic
resolution will require additional study (WDFW 2001c).
The Columbia Basin population segment also exhibits significantly
less genetic diversity compared to the other pygmy rabbit populations--
a likely result of long-term isolation. Peripheral and isolated
populations may experience increased directional selection due to
marginal or varied habitats or species compositions at range
peripheries, exhibit adaptations specific to these differing selective
pressures, demonstrate genetic consequences of reduced gene flow
dependent on varying levels of isolation, or have different responses
to anthropogenic influences (Levin 1970; MacArthur 1972; Morain 1984;
Lacy 1987; Hengeveld 1990; Saunders et al. 1991; Hoffmann and Blows
1994; Furlow and Armijo-Prewitt 1995; Garcia-Ramos and Kirkpatrick
1997). In addition, the level of genetic diversity found in tissue
samples collected in Washington in the 1990s showed a continued and
accelerated reduction in genetic variability, which may be associated
with a recent rapid decline in population size and health (WDFW 2001c).
Data showing a reduced within-individual genetic diversity suggest that
the Washington population segment also may be experiencing a small
degree of inbreeding (WDFW 2001c).
Based upon the above results of genetic analyses, it is clear that
(1) the unique characteristics of the Columbia Basin population segment
of pygmy rabbits represent an important component in the evolutionary
legacy of the species and, therefore, a genetic resource worthy of
conservation; and (2) efforts should be undertaken to address the
recent decline in genetic diversity within this population segment (K.
Warheit, pers. comm., 2001).
Persistence in an unusual or unique ecological setting. With regard
to the historic distribution of the pygmy rabbit, several studies have
defined and mapped landscape-level ecosystem components of Washington
and Oregon and, to varying degrees, address the management of natural
resources within these regional ecosystems (Daubenmire 1988; Franklin
and Dyrness 1988; Keane et al. 1996; Quigley et al. 1997; Wisdom et al.
1998). There are a number of differences between these studies,
however, the ecosystem mapping units that result are relatively
consistent. This landscape level approach is important in determining
if the population segment of the pygmy rabbit that remains in central
Washington may occupy an unusual or unique ecological setting. In
addition, its utility is valuable for determining the bounds of any
potential DPS in the region, as required by our DPS policy.
During the early 1900s, the pygmy rabbit populations in Washington
and Oregon (Figure 2) occurred in five ecosystems identified by the
above studies. For the purposes of this DPS analysis, we refer to these
ecosystems as the Columbia Basin, High Lava Plains, Northern Great
Basin, Owyhee Uplands, and Modoc Plateau (after Quigley et al. 1997).
The Columbia Basin occurs in Washington and northern Oregon; the other
four ecosystems occur in central and southern Oregon (Figure 3). These
ecosystems are interspersed to varying degrees with forested habitats
of the Southern and Eastern Cascades ecosystems to the west, Okanogan
Highlands to the north, and the Bitterroot and Blue Mountains to the
east; and steppe (grassland) habitats of the Palouse Prairie to the
east.
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The population segment of the pygmy rabbit in central Washington
occurs entirely within the Columbia Basin, and has been the only
representation of the taxon within this ecosystem for thousands of
years. During the early 1900s, the population segment of the pygmy
rabbit in central and southern Oregon was apparently locally dispersed
across the High Lava Plains, Northern Great Basin, Owyhee Uplands, and
Modoc Plateau (cf. Figures 2 and 3). The distribution of the pygmy
rabbit in Oregon has likely declined during the last century (Weiss and
Verts 1984; WDFW 2000b) and, currently, occurs primarily within the
Northern Great Basin ecosystem.
A number of significant differences are found between the Columbia
Basin and the balance of pygmy rabbit range in central and southern
Oregon (Table 1). In general, the Columbia Basin is lower in elevation,
contains soils of varying origin, and has been influenced by different
geological processes. These structural differences, combined with
regional climatic conditions, significantly influence the broad plant
associations found within each ecosystem (Daubenmire 1988; Franklin and
Dyrness 1988). Historically, transitional steppe habitats were much
more prevalent in the Columbia Basin than in the ecosystems of central
and southern Oregon. In contrast, juniper (Juniperus spp) woodlands and
salt-desert shrub habitats were much more common in central and
southern Oregon. Finally, there are significant differences in the type
and distribution of sagebrush taxa among the ecosystems (Table 1).
Table 1.--Differences in ecosystem elements between regions occupied by
the extant population segments of the pygmy rabbit in Washington and
Oregon (after Winward 1980, Daubenmire 1988, Franklin and Dyrness 1988,
McNab and Avers 1994, Dobler et al. 1996, and Quigley et al. 1997).

Ecosystem Elements: Geologic, Edaphic, and Transitional Habitats
--------------------------------------------------------------------------------------------------------------------------------------------------------
Channeled Internally- Juniper Salt-desert
Population segment Elevations Soils scablands drained playas Steppe woodland shrub
--------------------------------------------------------------------------------------------------------------------------------------------------------
Columbia Basin............... 3,000 ft........ Deep/Loamy Prominent Rare/Absent..... Abundant (east) Rare/Absent.... Rare/Absent.
Glacial/Eolian. (north).
Central/Southern Oregon...... >3,500 ft....... Thin/Rocky Rare/Absent..... Prominent (NGB, Rare/Absent.... Abundant (HLP) Abundant (NGB,
Volcanic (HLP) OU). Present (NGB, OU).
Deep/Alluvial OU).
(NGB, OU) \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Ecosystem Elements: Sagebrush (Artemsia) Taxa \2\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Population segment Basin ssp Wyoming ssp Mountain ssp Low Three-tip Stiff Early Silver Black
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Columbia Basin................ Dominant........ Present (west).. Rare/Absent..... Rare/Absent..... Abundant (north) Abundant........ Rare/Absent..... Rare/Absent..... Rare/Absent.
Central/Southern Oregon....... Rare/Absent..... Dominant........ Abundant........ Abundant........ Present (OU).... Present......... Present (HLP)... Present (NGB, Present (NGB,
OU). OU).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Element primarily applies to the ecosystems noted: HLP--High Lava Plains; NGB--Northern Great Basin; OU--Owyhee Uplands.
\2\ Big Sagebrush (A. tridentata) Subspecies (ssp): Basin--A.t. tridentata, Wyoming--A.t. wyomingensis, Mountain--A.t. vaseyana; Low--A. arbuscula; Three-tip--A. tripartita; Stiff--A. rigida;
Early--A. longiloba; Silver--A. cana; Black--A. nova.

There are a number of broad habitat associations in common between
the Columbia Basin and the ecosystems of central and southern Oregon
(Daubenmire 1988; Franklin and Dyrness 1988). However, even within
these common habitat associations, notable differences exist. In
general, the composition of forb species differs considerably between
the Columbia Basin and the ecosystems in central and southern Oregon
(cf Daubenmire 1988 and Franklin and Dyrness 1988). Even when the same
forb species may be present, the two regions typically support
different subspecies or varieties of these taxa (Hitchcock and
Cronquist 1973).
Currently, it is unclear if pygmy rabbits occupying the Columbia
Basin are different behaviorally or morphologically from other pygmy
rabbits throughout the remainder of their historic range. However,
based on the above information and the pygmy rabbit's close association
with sagebrush ecosystems, we conclude that the Columbia Basin
represents a unique ecological setting for the taxon due to its
different geologic, climatic, edaphic (soil), and plant community
components. The unique elements of the Columbia Basin respectively hold
unique management implications for pygmy rabbits within this ecosystem
(see Table 1).
Conclusion of DPS Evaluation. Based on the above consideration of
the Washington population of the pygmy rabbit's discreteness and
significance to the remainder of the species, we find that the
population segment does represent a DPS. The population's discreteness
is due to both its spatial and temporal separation from the remainder
of the species. These separations are translated into ecological,
physical, and genetic differences that account for the population's
discreteness. The population segment's significance to the remainder of
the taxon is due to (1) The unique genetic characteristics it
possesses, (2) the significant gap in the historic range of the taxon
that its loss would represent, and (3) the unique ecological setting of
the Columbia Basin in which it persists.
As required by our DPS policy, we have determined that the bounds
of this DPS are conterminous with the historic distribution of the
pygmy rabbit within the Columbia Basin ecosystem (Figure 2). We refer
to this population segment as the Columbia Basin pygmy rabbit for the
remainder of this emergency rule and the accompanying proposed rule.

Status

After a thorough review and consideration of all available
information, we have determined that the Columbia Basin pygmy rabbit is
a DPS. To determine if the DPS should be listed as threatened or
endangered, we

[[Page 59744]]

evaluate on the five factors described in section 4(a)(1) of the Act.
These factors and their application to the Columbia Basin pygmy rabbit
follows.

Summary of Factors Affecting the Species

After a thorough review and consideration of all available
information, we have determined that the Columbia Basin pygmy rabbit
warrants classification as an endangered species. We followed
procedures found in section 4 of the Act and regulations promulgated to
implement the listing provisions of the Act (50 CFR part 424). We may
determine a species to be endangered or threatened due to one or more
of the five factors described in section 4(a)(1). These factors and
their application to the Columbia Basin pygmy rabbit follows.
A. Present or threatened destruction, modification, or curtailment
of habitat or range. Reduction of the shrub steppe habitat of the
Columbia Basin that is required by the pygmy rabbit began in the
historic past and currently threatens extant populations of the
species. During the first half of the 1900s, large portions of more
mesic (moist) shrub steppe habitats on deeper soils within the Columbia
Basin were converted for dryland crop production (Daubenmire 1988;
Franklin and Dyrness 1988; WDFW 1995). During the mid-1900s, large-
scale irrigation projects led to further conversion of more xeric (dry)
shrub steppe habitats on deeper soils within the Columbia Basin for
irrigated agriculture (WDFW 1995; Franklin and Dyrness 1988; U.S.
Department of Interior (USDI) 1998). While currently at reduced levels,
conversion of shrub steppe habitats to both dryland and irrigated crop
production within the Columbia Basin continues. In addition, urban and
rural developments (e.g., housing, industrial facilities,
transportation corridors) in central Washington permanently remove
native shrub steppe habitats.
In 1994, it was estimated that approximately 60 percent of the
original shrub steppe habitat in Washington had been converted for
human uses (Dobler 1994). The Columbia Basin pygmy rabbit can not
occupy these converted sites. Due to the small home ranges and
relatively restricted movements of pygmy rabbits, conversion of native
habitats in the Columbia Basin also removes or severely limits their
dispersal corridors between suitable habitats.
A number of other, often interacting, influences affect the
remaining native shrub steppe habitat within the Columbia Basin,
including altered fire frequencies, invasion by non-native species,
recreational activities, and grazing. Sagebrush is easily killed by
fire and, when it occurs at increased frequencies, can remove sagebrush
from the vegetation assemblage (Daubenmire 1988). In the absence of a
sufficient seed source, sagebrush can not readily reinvade sites where
it has been removed, and it may be many years before it can become
reestablished (WDFW 1995). Due to a variety of factors (see below), the
fire frequency has increased over portions of the remaining shrub
steppe habitat within the Columbia Basin. Because of their close
association with tall, dense stands of sage brush, pygmy rabbits are
precluded from occupying frequently burned areas.
Various non-native, invasive plant species, such as cheatgrass and
knapweed (Centauria spp), have become well established throughout the
Columbia Basin (Daubenmire 1988; Franklin and Dyrness 1988). Areas with
dense cover of cheatgrass are apparently avoided by pygmy rabbits
(Weiss and Vert 1984). In addition, these newly established plant
communities often provide fine fuels that can carry a fire. Combined
with widespread unimproved road access and informal recreational
activities that provide multiple sources of ignition, the establishment
of non-native species increases the risk of fire and further reduces
the security of areas that could potentially support the Columbia Basin
pygmy rabbit (WDFW 1995).
Land managed for grazing is often cleared of sagebrush to increase
the production of grasses and forbs as forage for cattle (WDFW 1995;
Rauscher 1997). Clearing large areas of sagebrush cover removes habitat
patches potentially used by the Columbia Basin pygmy rabbit. In
addition, it can reduce the value of more marginal stands of sagebrush
that may act as dispersal corridors for pygmy rabbits, further
fragmenting the remaining suitable habitats. Cattle may also damage
pygmy rabbit burrow systems through trampling (Rauscher 1997; N.
Siegel, WSU, pers. comm., 2001). Much of the remaining shrub steppe
habitat in the Columbia Basin is managed for livestock grazing (WDFW
1995; N. Hedges, pers. comm., 2001).
Excessive grazing removes current herbaceous growth and residual
cover of native grasses and forbs, and can increase the density of
various non-native, invasive species and young sagebrush stands
(Daubenmire 1988; WDFW 1995). In some instances, this disturbance may
eventually result in the growth of the tall, dense stands of sagebrush
(Ellison 1960), potentially improving cover conditions for pygmy
rabbits. However, grazing at these levels potentially reduces the
forage base of grasses and forbs for Columbia Basin pygmy rabbits
during spring and summer (Green and Flinders 1980b; Rauscher 1997).
Excessive grazing may also cause structural damage to dense stands of
older sagebrush due to trampling. This acts to open the canopies of
these sites and potentially makes them less suitable as cover for
Columbia Basin pygmy rabbits (Gahr 1993; Rauscher 1997). Currently, it
is unclear if light or moderate levels of grazing may be compatible
with pygmy rabbit conservation efforts, or, due to the current threat
of extirpation, if any grazing is appropriate at this time. However,
there are several ongoing studies investigating the effects of
different grazing strategies on Columbia Basin pygmy rabbits and their
habitat (WDFW 1995; Sayler et al. 2001; L. Shipley, pers. comm., 2001).
Due to the above combined influences, Washington's native shrub
steppe habitats, including those considered essential to the long-term
security of the Columbia Basin pygmy rabbit, are considered among the
least-protected areas in the State (Cassidy 1997). Although many
factors are affecting the decline of the Columbia Basin pygmy rabbit,
the current population crisis is indirectly due to a lack of good,
quality habitat that offers a balance of nutritional forage to maintain
a healthy, disease-free, and growing population (see factor C) and
cover for protection from predators and extreme weather conditions (see
factors C and E).
B. Over-utilization for commercial, recreational, scientific, or
educational purposes. Pygmy rabbits are often difficult to distinguish
from species of cottontail rabbits (Sylvilagus spp.) (Garber 1993; WDFW
1995). Because of this, accidental shooting of Columbia Basin pygmy
rabbits may occur in association with hunting of other small game
species in Washington (WDFW 1979). Due to their extremely low numbers,
restricted distribution, and preference for dense habitats, combined
with relatively few visitors to the Sagebrush Flat site, the risk from
incidental shooting of Columbia Basin pygmy rabbits is nominal (WDFW
1995; D. Hays, pers. comm., 2001). However, in such reduced
populations, this possible source of mortality could lead to
extirpation, if it is not controlled.
Investigations that require trapping, handling, and captivity of
pygmy rabbits can result in mortality from several causes, including
exposure (due to

[[Page 59745]]

excessively high or low temperatures), direct injury from entanglement
in traps, trap predation, intra-specific fighting, and capture stress
(Bailey 1936; Severaid 1950; Wilde 1978; Gahr 1993; Rauscher 1997).
Capture-related mortality rates (including recaptures) reported for
pygmy rabbits are roughly 3 percent (Gahr 1993), 5 percent (Wilde
1978), and 13 percent (Rauscher 1997). The mortality rate for one study
approached 20 percent when the total number of captured animals was
considered (11 deaths of 58 individuals). All of the mortalities in
this study occurred in just one portion of the study area (Rauscher
1997). Trapping methods, daily and seasonal timing, study location,
holding facilities, and husbandry techniques may all affect the level
of capture-related mortality incurred.
Some pygmy rabbit burrows are relatively shallow and may collapse
when walked on by humans or any similarly large animal (Wilde 1978). In
addition, investigations of pygmy rabbits often entail the destruction
of individual burrows, measuring of the vegetation community and other
site characteristics immediately surrounding burrow systems, and/or
disturbance to the general area occupied by colonies (Janson 1946;
Bradfield 1974; Green 1978; Wilde 1978; Gahr 1993; Gabler 1997;
Rauscher 1997).
It is unlikely that any of the above activities alone have played a
significant role in the long-term population decline and range
reduction of the Columbia Basin pygmy rabbit. However, due to the
vulnerability of the extant population, any source of mortality that
does not contribute directly to efforts to conserve the remaining wild
and captive portions of the Columbia Basin pygmy rabbit population may
contribute to its extirpation.
C. Disease or predation. Pygmy rabbits often harbor a high parasite
load (Gahr 1993; WDFW 1995). Some of the parasites of pygmy rabbits,
including ticks, fleas, and lice, can be vectors of disease. Episodes
of plague and tularemia from these vectors have been reported in
populations of a number of other Leporid species and are often rapidly
spreading and fatal (Quan 1993). Severe disease epidemics have not been
reported in pygmy rabbits, and parasites have not been viewed as a
significant threat to the species (Davis 1939; Gahr 1993). However,
recent evidence of plague found in a coyote in Sagebrush Flat has
raised concern (WDFW 2001a). The potential for disease outbreaks within
the remaining wild and captive portions of the Columbia Basin pygmy
rabbit population remain, particularly where the population is stressed
by predation and lack of adequate nutrition. The level of risk from
disease to the Columbia Basin population segment is currently being
investigated (WDFW 2001a).
Predation is thought to be a major cause of mortality among pygmy
rabbits (Green 1979; Wilde 1978). While pygmy rabbits have adapted to
the presence of a wide variety of predators that occur throughout their
historic distribution (Janson 1946; Gashwiler et al. 1960; Green 1978;
Wilde 1978; WDFW 1995), the threat of predation on the single extant
population is great. Predation is not likely to represent a significant
threat to relatively large, well-distributed pygmy rabbit populations.
However, due to the extremely small size and localized occurrence of
the Columbia Basin pygmy rabbit population, reducing or eliminating
predation may play a significant role in conservation efforts for the
remaining wild and captive portions of this population segment.
D. Inadequacy of existing regulatory mechanisms. The Washington
State classification of the Columbia Basin pygmy rabbit as endangered
makes it illegal to attempt to kill, injure, capture, harass, possess,
or control individuals of the species (WDFW 1995). However, illegal or
incidental shooting of pygmy rabbits may occur in association with
hunting seasons for other small game species (see factor C above). In
addition, State designation does not provide regulatory protection of
the habitats considered essential to the long-term security of the
Columbia Basin pygmy rabbit.
Currently, we are assisting private landowners with development of
a county-wide HCP to protect important plant and animal species on
agricultural lands in Douglas County. However, there are no regulatory
protections for unlisted species during development of HCPs, and
recovery of listed species may not be assured through management
actions undertaken solely on private lands.
Revegetation standards under the CRP promote the improvement of
habitats potentially used by the Columbia Basin pygmy rabbit, and the
CRP restricts livestock grazing on contract lands except under severe
drought conditions (M. Ruud, Farm Service Agency, pers. comm., 2001).
However, these measures are not specifically promulgated for the
protection of the Columbia Basin pygmy rabbit, and there are few other
mechanisms that regulate grazing practices or the conversion of native
habitats on privately owned lands.
E. Other natural or human-caused factors affecting the species
continued existence. Presently, the primary threats to the Columbia
Basin pygmy rabbit population are associated with its extremely small
size, limited distribution, and level of fragmentation (see Reasons for
Emergency Determination). Small populations are susceptible to random
weather events (e.g., severe storms, drought, and extended cold
spells), changes in cover and food resources, disease outbreaks,
altered predation or parasite populations, and fire. Small populations
are also more susceptible to demographic and genetic problems (Caughly
and Gunn 1996). These threat factors, which may act in concert, include
natural variation in survival and reproductive success of individuals,
chance imbalanced of sex ratios, changes in gene frequencies due to
genetic drift, and lack of genetic diversity caused by inbreeding. Due
to these combined influences, and its inability to be ``rescued'' by
nearby populations should it become extirpated, the Columbia Basin
pygmy rabbit population is currently believed to be below the level
necessary to ensure its long-term viability (WDFW 1995).
Conclusion of Status Evaluation. Based upon our evaluation of the
above five factors that may threaten the Columbia Basin DPS of the
pygmy rabbit, using the best scientific and commercial data available,
we have determined the DPS to be in danger of extinction. The recent
loss of populations within the DPS, the very small number of
individuals within the remaining single wild population, and the
threats to this population concerned us to the extent that we decided
to further evaluate the status of this DPS and to consider an emergency
listing, as an endangered species. This further evaluation of the DPS's
status is discussed below.

Reasons for Emergency Determination

Under section 4(b)(7) of the Act, we must consider development of
an emergency rule to list a species if threats to the species
constitute an emergency posing a significant risk to its well-being.
Such an emergency listing expires 240 days following its publication in
the Federal Register unless, during the 240-day period, we develop a
final rule to list the species under our normal listing procedures.
Below, we discuss the reasons why emergency listing of the Columbia
Basin pygmy rabbit as endangered is necessary. In accordance with the
Act, we will withdraw this emergency rule

[[Page 59746]]

if, at any time after its publication, we determine that substantial
evidence does not exist to warrant such a rule.
The immediate concerns for the Columbia Basin pygmy rabbit are
associated with the population's extremely small size, history of
fragmentation and extirpation, and the recent, dramatic decline in its
distribution and abundance. In addition to the relatively large-scale
impacts to native shrub steppe habitats, various other human-caused and
naturally occurring impacts of lesser magnitude now pose significant
and imminent risks to this population segment. Due to the combined
influence of the following threats-environmental stochasticity and
catastrophe, predation, disease, and reduced genetic fitness-
extirpation of the Columbia Basin pygmy rabbit from the wild may occur
at any time (WDFW 2001b). In addition, the risks to the captive portion
of the population and the potential for extinction of the Columbia
Basin pygmy rabbit remain high.

Environmental Stochasticity and Catastrophes

Environmental stochasticities (random events) include the bad
winters, resource failures, plagues of predators, and such that deliver
shocks to populations. If a population is large enough, then such a
shock can be withstood, although mortality within the population may be
high. Often the population can rebound over time and recover its
population numbers, either through birth or immigration from nearby
populations. In the case of the Columbia pygmy rabbit, however, the
size of the extant population is too small to withstand shock, even a
small one, and be able to rebound; moreover, no neighboring population
exists to ``rescue'' it through immigration.
While there are numerous examples of possible stochastic events
that could affect the Columbia pygmy rabbit, fire has already had a
catastrophic effect on the species and remains a real threat to the
last remaining population. Fire was implicated in the loss of the only
pygmy rabbit colony ever recorded in Benton County, Washington, in 1979
(WDFW 1995), and was directly associated with the recent loss of one of
the few remaining colonies in Douglas County in 1999 (WDFW 2001b). The
WDFW has taken measures to reduce the risk from fire at the Sagebrush
Flat site (e.g., constructing firebreaks). However, unimproved road
access and informal recreational activities provide continuing sources
(e.g., people and vehicles) of uncontrolled fires at Sagebrush Flat
(WDFW 1995). Due to the population's small size, restriction to one
known site in the wild, and reliance on relatively tall, dense stands
of sagebrush, natural and human-caused fire represents a significant
threat to the Columbia Basin pygmy rabbit in the wild.
While plague is common in other Leporid species, it is not known in
pygmy rabbits. However, evidence of plague was reported in a coyote
taken from the site of one of the recently extirpated pygmy rabbit
colonies (WDFW 2001a). The potential occurrence of plague in this
colony is currently being investigated using blood samples obtained
prior to its extirpation (D. Hays, pers. comm., 2001). Additional
studies have been proposed to investigate the occurrence of diseases
and their possible control in wild and captive populations of pygmy
rabbits (C. Brand, National Wildlife Health Center, pers. comm., 2001).
Because so few Columbia Basin pygmy rabbits remain, disease epidemic
remains a significant threat to both the wild and captive portions of
this population segment.
Emergency listing the Columbia Basin pygmy rabbit will increase
regulatory efficiency in favor of protection for the species from
stochasticity and the funding to support immediate recovery activities
necessary for the species' survival. Protections could include
increased population numbers and distribution in the wild to withstand
catastrophe, and control of the sources of stochasticity and
catastrophe where possible.

Predation

Populations of pygmy rabbits have coexisted with various levels of
grazing throughout their historic range for many years (WDFW 1995).
However, due to the extremely low number and restricted distribution of
Columbia Basin pygmy rabbits, any additional mortality or population
stress associated with grazing practices potentially represents a
significant threat to the security of the wild portion of this
population segment. The effects of different grazing strategies on
Columbia Basin pygmy rabbits are not well understood (WDFW 1995).
However, Gahr (1993) found that male pygmy rabbits at the Sagebrush
Flat site made longer movements, resulting in larger home ranges,
during the breeding season in recently grazed areas as opposed to areas
that had not been grazed for nearly 40 years. In addition, relative to
unit size, there are more pygmy rabbit burrows in the ungrazed areas of
Sagebrush Flat than the recently grazed areas (L. Shipley and N.
Siegel, pers. comm., 2001). These results suggest that Columbia Basin
pygmy rabbits may be more susceptible to predation in areas used for
livestock grazing due to the necessarily longer movements away from
cover and fewer burrows available for escape.
Due to recent, confirmed evidence of coyote predation on pygmy
rabbits, the WDFW implemented an emergency coyote control program
during the fall-winter periods of 1998-1999 and 1999-2000 (WDFW 2000a).
Coyotes were removed, by shooting, traps, and snares, over roughly 20
square miles around and including the Sagebrush Flat site. The level of
effort to control coyotes varied in different years and areas, and the
efficacy of this program to protect the Columbia Basin pygmy rabbit is
unknown. A variety of other avian and terrestrial predators may occur
on sites currently occupied by the Columbia Basin pygmy rabbit. Because
of the relatively restricted distribution of this population segment,
combined with potential impacts from livestock grazing (above),
predators may have a reduced search area or increased success rate for
pygmy rabbits at these sites.
Within the captive breeding population sites of the Columbia Basin
pygmy rabbit, several measures (e.g., double fencing and monitoring)
have been taken to reduce the risk of predation (L. Shipley and R.
Sayler, WSU, pers. comm., 2001). However, while the risk has been
reduced, currently only a single captive-rearing facility is in
operation and the potential for predators to access some of the outdoor
cages at this facility remains.
Even low levels of predation represent a significant risk to the
immediate security of both the wild and captive portions of this
species. Emergency listing of the Columbia Basin pygmy rabbit as
endangered will increase the regulatory protections and resources for
predator control and other forms of range management until this
population can withstand ``normal'' predation pressure.

Viability, Fitness

Genetic indices indicate that the Columbia Basin pygmy rabbit has
significantly less genetic diversity than the remainder of the taxon.
In addition, this population segment has undergone an accelerated loss
of genetic diversity since the mid-1900s. Severe loss of genetic
diversity may make the Columbia Basin pygmy rabbit more susceptible to
extinction due to inbreeding depression. Reduced genetic diversity and
the relatively few family lineages remaining in the Columbia Basin
pygmy rabbit population also may complicate captive breeding strategies

[[Page 59747]]

conducted to reestablish a minimum effective population size (i.e., the
number of individuals contributing to reproduction). Ultimately, an
appropriate effective population size will help to ensure the
maintenance and enhancement of the genetic heterogeneity still present
within this population segment (K. Warheit, pers. comm., 2001).
Reproductive fitness is not only a function of genetic health,
however; nutritional stress also may have a devastating effect on
reproductive fitness and the overall viability of a population,
particularly in the defense of diseases and plagues; animal populations
are ultimately limited by the capacity of the environment to support
them. The preliminary results of an ongoing study indicate that pygmy
rabbits occupying sites where cattle grazing occurs may have a greater
proportion of their spring and summer diets composed of sagebrush as
opposed to the grasses that they require at this time of year, which is
usually as much as 40 percent (L. Shipley and N. Siegel, pers. comm.,
2001). This result provides support for the contention that livestock
may compete directly with pygmy rabbits for available forage (Green and
Flinders 1980b; Rauscher 1997), thus causing the rabbits to become
nutritionally stressed at a time when they require grass in their diet
or the population level to become lower than the land would support
without the influence of livestock.

Summary of Emergency Determination

Due to the extremely small size of the Columbia Basin pygmy rabbit
population, even a low level of mortality due to stochastic events,
disease, nutritional stress, and predation represents a significant
risk to the immediate security of both the wild and captive portions of
the species. Emergency listing of the Columbia Basin pygmy rabbit as
endangered will increase the regulatory protections and resources
available to the species in predator control and other forms of range
management that are designed to improve the nutritional capacity of the
habitat in favor of the pygmy rabbit. Recovery of the Columbia Basin
pygmy rabbit is dependent upon a self-sustaining wild population that
can withstand the threats that could lead to extinction.
Reestablishment, therefore, of a wild population through the use of a
rigorous captive propagation program is a necessary step towards
recovery.

Critical Habitat

Critical habitat is defined in section 3 of the Act as--(i) the
specific area within the geographical area occupied by a species, at
the time it is listed in accordance with the Act, on which are found
those biological features (I) essential to the conservation of the
species and (II) that may require special management considerations or
protection; and (ii) specific areas outside the geographical area
occupied by a species at the time it is listed, upon a determination
that such areas are essential for the conservation of the species.
``'Conservation''' means the use of all methods and procedures needed
to bring the species to the point at which listing under the Act is no
longer necessary.
Section 4(a)(3) of the Act and its implementing regulations (50 CFR
424.12) require that, to the maximum extent prudent and determinable,
the Secretary of the Interior (Secretary) designate critical habitat at
the time the species is determined to be endangered or threatened. The
implementing regulations state that critical habitat is not
determinable if information sufficient to perform the required analyses
of impacts of the designation is lacking, or if the biological needs of
the species are not sufficiently well known to permit identification of
an area as critical habitat. Section 4(b)(2) of the Act requires us to
consider economic and other relevant impacts of designating a
particular area as critical habitat on the basis of the best scientific
data available. The Secretary may exclude any area from critical
habitat if she determines that the benefits of such exclusion outweigh
the conservation benefits, unless to do so would result in the
extinction of the species.
We find that designation of critical habitat for the Columbia Basin
pygmy rabbit is not determinable at this time because information
sufficient to perform the required analyses of the impacts of the
designation is lacking. We specifically solicit this information in the
proposed rule (see Public Comments Solicited section), published in
this same issue of the Federal Register. When a ``not determinable''
finding is made, we must, within 2 years of the publication date of the
original proposed rule, designate critical habitat, unless the
designation is found to be not prudent. We will protect the Columbia
Basin pygmy rabbit and its habitat through section 7 consultations to
determine whether Federal actions are likely to jeopardize the
continued existence of the species, through the recovery process,
through enforcement of take prohibitions under section 9 of the Act,
and through the section 10 process for activities on non-Federal lands
with no Federal nexus.

Available Conservation Measures

Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, requirements for Federal
protection, prohibitions against certain activities, and development of
recovery plans. Recognition through listing encourages conservation
actions by Federal, State, and tribal agencies, non-governmental
conservation groups, and private individuals. The Act provides for
potential land acquisition and cooperation with the States and requires
that recovery actions be carried out for listed species. Below, we
discuss the requirements of Federal agencies, considerations for
protection and conservation actions, and the prohibitions against
taking and harm for the Columbia Basin pygmy rabbit.
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as
endangered or threatened, and with respect to its critical habitat when
it is designated. Federal agencies are required to confer with us on
any action that is likely to jeopardize the continued existence of a
proposed species or result in destruction or adverse modification of
proposed critical habitat. When a species is listed as threatened or
endangered, Federal agencies must ensure that the activities they
authorize, fund, or carry out are not likely to jeopardize the
continued existence of such a species, or to destroy or adversely
modify its critical habitat. If a Federal action may affect a listed
species or its critical habitat, the responsible Federal agency must
enter into consultation with us. Federal agency actions that may
require consultation for the Columbia Basin pygmy rabbit include, but
are not limited to, those within the jurisdictions of the U.S. Fish and
Wildlife Service, Bureau of Land Management, Bureau of Reclamation,
Natural Resources Conservation Service, and Farm Service Agency.
We believe that protection and recovery of the Columbia Basin pygmy
rabbit, in both wild and in captive breeding populations, will require
reduction of the threats from uncontrolled fire, excessive livestock
grazing, altered predation patterns, disease, and loss of genetic
viability. These threats should be considered for management actions in
habitats currently and potentially occupied by the Columbia Basin pygmy
rabbit, and those deemed important for dispersal between their
appropriate use areas. Monitoring should also be undertaken

[[Page 59748]]

for any management actions or scientific investigations designed to
address these threats or their potential impacts.
Listing the Columbia Basin pygmy rabbit provides for the
development and implementation of a recovery plan for the species. This
plan will bring together Federal, State, and local efforts for
conservation of the species. A recovery plan will establish a framework
for agencies to coordinate their recovery efforts. The plan will set
recovery priorities and estimate the costs of the tasks necessary to
accomplish the priorities. It will also describe the site-specific
management actions necessary to achieve conservation and survival of
the species.
Listing will require us to review and provide direction or guidance
on any actions that may affect the Columbia Basin pygmy rabbit on lands
or activities under Federal jurisdiction, State plans developed
pursuant to section 6 of the Act, scientific investigations and efforts
to enhance the propagation or survival of the population segment
pursuant to section 10(a)(1)(A) of the Act, and Conservation Plans
developed for non-Federal lands and activities pursuant to section
10(a)(1)(B) of the Act.
Considerations for management actions and scientific investigations
to address the above threats to the Columbia Basin pygmy rabbit
include, but are not limited to:
(1) Fire: Implementation of agreements between fire-fighting
districts to provide adequate coverage, construction of fire breaks,
availability of fire-fighting equipment, fire-fighting techniques, weed
control, use of prescribed fire, and removal or restriction of
unimproved road access and informal recreational activities;
(2) Livestock Grazing: Season(s) of use, stocking rate(s) and
type(s), location of supplemental watering and salting, loading and
transport facilities, exclusion fencing, and removal;
(3) Predation: Identification of primary predators and predation
patterns, development of protocols for fence removal and/or new fence
construction, and predator deterrents and/or lethal control of
predators to protect the wild and captive portions of the population;
(4) Disease: Identification and control of potential disease and
disease vectors in wild and captive portions of the population;
(5) Capture, Husbandry, and Release: Development of protocols for
capture and handling, establishment of multiple holding facilities for
captive stock, inventory and evaluation of appropriate release sites,
and development of release protocols;
(6) Genetics: Identification of additional genetic markers,
implementation of an appropriate breeding scenario, and establishment
of a minimum effective population for captive breeding and release
efforts.
The Act sets forth a series of general prohibitions and exceptions
that apply to all endangered wildlife species. The prohibitions make it
illegal for any person subject to the jurisdiction of the United States
to take (including harass, harm, pursue, hunt, shoot, wound, kill,
trap, capture, collect, or attempt any such conduct), import or export,
transport in interstate or foreign commerce in the course of commercial
activity, or sell or offer for sale in interstate or foreign commerce
any endangered wildlife species. It is also illegal to possess, sell,
deliver, carry, transport, or ship any such wildlife that has been
taken illegally. Certain exceptions apply to our agents and State
conservation agencies. Permits may be issued to carry out otherwise
prohibited activities involving listed species. Such permits are
available for scientific purposes, to enhance the propagation or
survival of the species, or for incidental take in connection with
otherwise lawful activities.
It is our policy, published in the Federal Register on July 1, 1994
(59 FR 34272), to identify, to the maximum extent practical at the time
a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a listing on
proposed and ongoing activities within a species' range. For the
Columbia Basin pygmy rabbit, activities that we believe are unlikely to
result in a violation of section 9 include:
(1) Possession, delivery, or movement, including interstate
transport and import into or export from the United States of dead
specimens of Columbia Basin pygmy rabbits that were collected prior to
the date of publication of this emergency listing rule in the Federal
Register;
(2) Any action authorized, funded, or carried out by a Federal
agency that may affect the Columbia Basin pygmy rabbit when the action
is conducted in accordance with incidental take statement issued under
section 7 of the Act;
(3) Any action carried out for scientific research or to enhance
the propagation or survival of the Columbia Basin pygmy rabbit that is
conducted in accordance with the conditions of a section 10(a)(1)(A)
permit; and
(4) Any indidental take of the Columbia Basin pygmy rabbit
resulting from an otherwise lawful activity conducted in accordance
with the conditions of an incidental take permit issued under section
10(a)(1)(B) of the Act. Non-Federal applicants design a conservation
plan (HCP) for the species and apply for an incidental take permit.
These are developed for listed species and are designed to minimize and
mitigate impacts to the species to the greatest extent practicable.
Activities that we believe could potentially result in a violation
of section 9 include, but are not limited to:
(1) Activities authorized, funded, or carried out by Federal
agencies (e.g., land exchanges, land clearing, prescribed burning,
grazing, pest control, utility line or pipeline construction, mineral
and housing development, off-road vehicle use, recreational trail and
campground development, and road construction) that may affect the
Columbia Basin pygmy rabbit or its critical habitat when such
activities are not conducted in accordance with an incidental take
statement issued under section 7 of the Act;
(2) Unauthorized possession, trapping, handling, collecting, or
release of pygmy rabbits within the historic range of the Columbia
Basin pygmy rabbit. Research efforts involving these activities will
require a permit under section 10(a)(1)(A) of the Act;
(3) Activities that directly or indirectly result in the death or
injury of Columbia Basin pygmy rabbits, or that modify occupied habitat
and kill or injure them by significantly impairing their essential
behavioral patterns (e.g., shooting, poisoning, habitat conversion,
grazing, road and trail construction, water development and
impoundment, mineral extraction or processing, off-road vehicle use,
and unauthorized application of herbicides or pesticides in violation
of label restrictions). Otherwise lawful activities that incidentally
take Columbia Basin pygmy rabbits will require a permit under section
10(a)(1)(B) of the Act.
Questions regarding specific activities should be directed to our
Upper Columbia Fish and Wildlife Office (see ADDRESSES section).
Requests for copies of the regulations regarding listed wildlife,
including prohibitions and issuance of permits under the Act, may be
addressed to the U.S. Fish and Wildlife Service, Ecological Services,
Endangered Species Permits, 911 Northeast 11th Avenue, Portland, Oregon
97232-4181 (telephone (503) 231-2063; facsimile (503) 231-6243).

[[Page 59749]]

National Environmental Policy Act

We have determined that environmental assessments and environmental
impact statements, as defined in the National Environmental Policy Act
of 1969, need not be prepared in connection with regulations adopted
pursuant to section 4(a) of the Endangered Species Act of 1973, as
amended. We published a notice outlining our reasons for this
determination in the Federal Register on October 25, 1983 (48 FR
49244).

Paperwork Reduction Act

This rule does not contain any new collections of information other
than those already approved under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq., and assigned Office of Management and Budget
clearance number 1018-0094. An agency may not conduct or sponsor, and a
person is not required to respond to, a collection of information
unless it displays a currently valid control number. For additional
information concerning permit and associated requirements for
endangered species, see 50 CFR 17.21 and 17.22.

Executive Order 13211

On May 18, 2001, the President issued an Executive Order (E.O.
13211) on regulations that significantly affect energy supply,
distribution, and use. Executive Order 13211 requires agencies to
prepare Statements of Energy Effects when undertaking certain actions.
This rule is not expected to significantly affect energy supplies,
distribution, or use. Although this rule is a significant regulatory
action under Executive Order 12866, it is not expected to significantly
affect energy supplies, distribution, or use. Therefore, this action is
not a significant energy action and no Statement of Energy Effects is
required.

References Cited

A complete list of references cited herein is available upon
request from the Upper Columbia Fish and Wildlife Office (see ADDRESSES
section).

Author

The primary author of this emergency rule is Christopher Warren of
the Upper Columbia Fish and Wildlife Office (see ADDRESSES section).

List of Subjects in 50 CFR Part 17

Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.

Regulation Promulgation

Accordingly, we amend part 17, subchapter B of chapter I, title 50
of the Code of Federal Regulations, as set forth below:

PART 17--[AMENDED]

1. The authority citation for part 17 will read as follows:

Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.

2. In Sec. 17.11(h), add the following to the List of Endangered
and Threatened Wildlife in alphabetical order under MAMMALS:

Sec. 17.11 Endangered and threatened wildlife.

* * * * *
(h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate population
---------------------------------------------------------- Historic Range where endangered or Status When Critical Special
Common name Scientific name threatened listed habitat rules
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mammals

* * * * * * *
Rabbit, Columbia Basin pygmy...... Brachylagus U.S.A. (Western U.S.A. (WA--Douglas, E ......... NA NA
idahoensis. conterminous States). Grant, Lincoln,
Adams, Benton
Counties).

* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

Dated: November 21, 2001.
Marshall P. Jones, Jr.,
Acting Director, Fish and Wildlife Service.
[FR Doc. 01-29615 Filed 11-29-01; 8:45 am]
BILLING CODE 4310-55-P

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Endangered and Threatened Wildlife and Plants; Emergency Rule To List the Columbia Basin Distinct Population Segment of the Pygmy Rabbit (Brachylagus idahoensis) as Endangered

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