SOME COMMONLY ASKED QUESTIONS AND ANSWERS
What is covered in the U.S. Fish and Wildlife Service's announcement about the Columbia Basin pygmy rabbit? We have exercised our authority to emergency list the Columbia Basin pygmy rabbit under the emergency provisions of the Endangered Species Act, which will afford it immediate Federal protection for a period of 240 days. We have also published a proposed rule to list this distinct population segment under our normal listing procedures, which specifically solicits comments and additional information from the general public, other governmental agencies, the scientific community, industry, or other interested parties concerning any future listing actions we may undertake for this species.
What are Columbia Basin pygmy rabbits? The pygmy rabbit is the smallest rabbit in North America, with adults weighing approximately 1 pound and measuring less than 1 foot in length. The pygmy rabbit is one of only two rabbit species in North America that digs its own burrows, and it is usually found in areas of dense sagebrush cover in relatively deep, loose soils. The Columbia Basin pygmy rabbit has been isolated from other pygmy rabbit populations for thousands of years, and it is markedly different genetically and occupies an unusual ecological setting compared to the remainder of the species.
What do Columbia Basin pygmy rabbits look like? Their overall color is slate-gray tipped with brown. They have whitish bellies, cinnamon-brown legs and chests, and short, rounded ears. In general appearance, they may be confused with cottontail rabbits, however, their tails are very small, lack any white fur, and are nearly unnoticeable in the wild.
What do Columbia Basin pygmy rabbits eat? They depend almost exclusively on sagebrush for food during the winter and may have specialized adaptations to accommodate this unusual diet. From spring through fall, native bunch grasses and forb species (broad-leaved herbaceous plants) are also eaten by Columbia Basin pygmy rabbits along with sagebrush.
Where are Columbia Basin pygmy rabbits found? Columbia Basin pygmy rabbits historically occurred in central Washington, including areas in Douglas, Grant, Lincoln, Adams, and Benton Counties. Currently, they are only known from a single colony in southern Douglas County.
Why is there concern for the Columbia Basin pygmy rabbit? The number of Columbia Basin pygmy rabbit colonies and active burrows in Washington has declined dramatically over the past decade. The entire, wild pygmy rabbit population in Washington is now considered to consist of fewer than 50 individuals, possibly from just one known colony. This population segment is imminently threatened by small population size and level of fragmentation, coupled with habitat impacts, disease, predation, and inbreeding.
Are there any measures currently being taken to conserve the Columbia Basin pygmy rabbit? In cooperation with Washington State University and the Oregon Zoo, the Washington Department of Fish and Wildlife initiated a captive breeding program for the Columbia Basin pygmy rabbit in the spring of 2001. To date, 12 pygmy rabbits have been captured from the Washington population as an initial source for captive breeding efforts. Reproductive behavior has been observed, including the birth of a litter of five offspring that was conceived in the wild. The ultimate goals of this program are to maintain a sufficient number of Columbia Basin pygmy rabbits in captivity to ensure their long-term survival and to introduce surplus captive-bred animals to their native habitats to help reestablish a viable wild population.
The Nature Conservancy and Bureau of Land Management have land acquisition and exchange programs in central Washington, which consider long-term conservation measures for the Columbia Basin pygmy rabbit. In addition, the Foster Creek Conservation District is currently developing a Habitat Conservation Plan for private agricultural interests in Douglas County, which harbors the only known remaining colony.
What do threatened and endangered mean? An endangered species is defined as a species in danger of extinction. A threatened species is one that is likely to become endangered within the foreseeable future throughout all or a significant portion of its range.
What is a distinct population segment? The definition of species under the Endangered Species Act (Act) includes any subspecies of fish or wildlife or plants, and any distinct population segment (DPS) of any species of vertebrate fish or wildlife which interbreeds when mature. Therefore, we must consider for emergency listing any species, subspecies, or, for vertebrates, any DPS of these taxa if there is enough information to indicate that such action is warranted. To be considered a DPS, a population segment must meet two criteria under our DPS policy. First, it must be discrete, or separated, from other populations of its species or subspecies. Second, it must be significant to the rest of its species or subspecies.
How is the Columbia Basin pygmy rabbit discrete? Under our DPS policy, discreteness may be demonstrated by either, or both, of the following: a) physical, physiological, ecological, behavioral, morphological, or genetic discontinuity between population segments; or b) international governmental boundaries between which differences in regulatory mechanisms exist that are significant with regard to conservation of the taxon. Columbia Basin pygmy rabbits do not occur in Canada and, therefore, we did not address the international boundary criterion in our recent listing actions.
The population segment of pygmy rabbits that occurs within the Columbia Basin ecosystem, which extends from northern Oregon through eastern Washington, is believed to have been physically discrete from the remainder of the species' range for over 10,000 years. The pygmy rabbit apparently had a slightly broader distribution within the Columbia Basin ecosystem during the mid-Holocene era, or roughly 7,000 to 3,000 years before present. 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 ecosystem during the late Holocene era, or roughly 3,000 years ago up to the present. Recent research has also shown that this population segment is genetically discrete from the remainder of the range.
Based on the above information, we concluded that this population segment of pygmy rabbits is discrete from the remainder of the taxon.
How is the Columbia Basin pygmy rabbit significant? Our DPS policy provides several examples of the types of information that may demonstrate the significance of a population segment to the remainder of its taxon. The information that we addressed for our review of the Columbia Basin pygmy rabbit included: a) evidence that the discrete population segment differs markedly from other population segments in its genetic characteristics; (b) persistence of the discrete population segment in an ecological setting unusual or unique for the taxon; and c) evidence that loss of the discrete population segment would result in a significant gap in the range of the taxon.
a) Recent genetic research indicates that the population segment of the pygmy rabbit within the Columbia Basin is markedly different from other pygmy rabbit population segments. These differences are consistent in both mitochondrial DNA and nuclear DNA indices, and between recent and museum specimens. The Columbia Basin population segment also exhibits significantly less genetic diversity as compared to other pygmy rabbit populations, and the level of genetic diversity in this population segment has declined significantly since the mid-1900s. Two tentative conclusions have been drawn from this recent genetic information: 1) the unique characteristics of the Columbia Basin population segment represent a genetic resource worthy of conservation; and 2) efforts should be undertaken to address the low level of genetic diversity within this population segment.
b) We concluded that the Columbia Basin ecosystem of eastern Washington and northern Oregon represents a unique ecological setting due to its different geologic, climatic, soil, and plant community components as compared to the ecosystems of central and southern Oregon. In addition, the population of pygmy rabbits occurring within the Columbia Basin is closely linked with this ecological setting.
Based on the above information, we concluded that the discrete population segment of pygmy rabbits occurring within the Columbia Basin is significant to the remainder of the taxon, and thus represents a distinct population segment.
What areas are covered by the U.S. Fish and Wildlife Service's listing of the Columbia Basin Pygmy Rabbit? The accompanying map shows the boundary of the historic range of the Columbia Basin pygmy rabbit within Washington. Our emergency and proposed listing rules apply to pygmy rabbits within the historic range of this population segment.
What are the next steps for the U.S. Fish and Wildlife Service regarding the Columbia Basin pygmy rabbit? We intend that any final listing action we undertake for the pygmy rabbit will be as accurate and effective as possible. Therefore, our proposed rule specifically requests additional information and comments from the general public, other governmental agencies, the scientific community, industry, or any other interested party concerning our emergency and proposed rules for the Columbia Basin pygmy rabbit. Comments should be provided to us by January 29, 2001, and may be sent to: Supervisor, Upper Columbia Fish and Wildlife Office, U.S. Fish and Wildlife Service, 11103 East Montgomery Drive, Spokane, Washington 99206.
If we receive a request, in writing, by January 14, 2002, we will conduct a public hearing to present the information we have available and to answer questions concerning our work on the Columbia Basin pygmy rabbit. We will also continue to work cooperatively with other Federal, state, tribal, and private interests to stabilize and conserve the Columbia Basin pygmy rabbit.