Recovery plan for the Columbia Basin Distinct Population Segment of the pygmy rabbit (Brachylagus idahoensis)

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The Columbia Basin distinct population segment of the pygmy rabbit (Brachylagus idahoensis) was listed as an endangered species under an emergency regulation in 2001. The last known wild subpopulation of pygmy rabbits within the Columbia Basin was extirpated by early 2004, although other wild subpopulations may still exist on lands that have not yet been surveyed. In March 2007, 20 captive-bred, intercrossed pygmy rabbits were reintroduced to habitats historically occupied by the species in the Columbia Basin of central Washington. These captive-bred animals experienced very high mortality over the first several weeks following their release and none were believed to have survived through the spring of 2008. Reintroduction efforts were resumed in 2011 with new management measures, and the need for captive breeding efforts has diminished. The pygmy rabbit has been present within the Columbia Basin ecosystem, a geographic area that extends from northern Oregon through central Washington, for over 100,000 years. Pygmy rabbits occur in the semiarid shrub steppe biome of the Great Basin and adjacent intermountain regions of the western United States. Within this broad biome, pygmy rabbits are typically found in habitat types that include tall, dense stands of sagebrush (Artemisia spp.), on which they are highly dependent to provide both food and shelter throughout the year. The pygmy rabbit is one of only two native rabbit species in North America that digs its own burrows and, therefore, is most often found in areas with relatively deep, loose soils that allow burrowing. Large-scale loss and fragmentation of native shrub steppe habitats, primarily for agricultural development, likely played a primary role in the long-term decline of the Columbia Basin pygmy rabbit. However, it is unlikely that these factors alone directly influenced the eventual extirpation of all known subpopulations from the wild. Once a population declines below a certain threshold, it is at risk of extirpation from a number of influences including chance environmental events (e.g., extreme weather), catastrophic habitat loss or resource failure (e.g., from wildfire or insect infestations), predation, disease, demographic limitations, loss of genetic diversity, and inbreeding. At the time of emergency listing action in 2001, the Columbia Basin pygmy rabbit was imminently threatened by its small population size, loss of genetic diversity, and inbreeding depression, coupled with a lack of suitable, protected habitats in the wild. A phased approach for recovery planning has been prescribed by this Recovery Plan. The three general phases are 1) removal or abatement of imminent threats to the population and the potentially suitable shrub steppe habitats in the Columbia Basin; 2) reestablishment of an appropriate number and distribution of free-ranging subpopulations over the near term; and 3) establishment and protection of a sufficiently resilient, free-ranging population that would be expected to withstand foreseeable long-term threats. The biological planning and conservation design set forth in this recovery plan lay out the criteria for recovery and identify localities for implementing actions, while the recovery actions describe a process for implementing conservation on the ground, outcome-based monitoring to assess success, and ongoing assumption-driven research to test biological hypotheses important to management. To facilitate such a strategy, specific near-term (i.e., 2012 – 2021) and more general long-term objectives and criteria have been established. In addition, revised implementation schedules will be developed, as necessary, to reflect the knowledge gained, accomplishments met, potential future constraints encountered, and consequent refinements to near-term recovery objectives, criteria, and/or actions as recovery progresses. The goal of this Federal recovery effort is to reclassify the species as threatened and, ultimately, remove it from the Federal List of Endangered and Threatened Wildlife and Plants.

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Suggested Citation (from USFWS): U.S. Fish and Wildlife Service. 2012 [2013?]]. Recovery Plan for the Columbia Basin Distinct Population Segment of the Pygmy Rabbit (Brachylagus idahoensis). Portland, Oregon. ix + 109 pp.

[Note: The USFWS Recovery Plan website (http://ecos.fws.gov/tess_public/pub/speciesRecovery.jsp?sort=1) gives the "plan date" as 1/23/2013. But the suggested citation within the document gives 2012 as the publication date. Since this is the Final Plan, though, and since the definition of that means that the regional director has signed off on it and since that person's signature appears on the doc dated 12/11/2012, I'm using the suggested citation date of 2012 for SA coding purposes.]