Colombia Basin Pygmy Rabbit - Ashley Lam

https://www.oregonzoo.org/conserve/fighting-extinction-pacific-northwest/columbia-basin-pygmy-rabbits

Columbia Basin Pygmy Rabbit
By Ashley Lam

Description and Ecology
The Columbia Basin Pygmy rabbit (Brachylagus idahoensis) is the smallest rabbit in North America, with adults ranging in size from 9.3 to 11.6 inches, and weighing less than a pound. It is a member of the family Leporidae, which includes hares and rabbits. However, they are distinguishable from other Leporids by their small size, short ears, small hind legs, and lack of white on their tail. Their tails are quite small and uniform in color, and nearly unnoticeable in the wild. Fur color may range anywhere from brown to dark gray, with white around the outline of their ears. Females express sexual dimorphism and tend to be slightly larger than males. 

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Pygmy rabbits tend to have an affinity for tall, dense sagebrush, which they are highly dependent upon because it covers their burrow sites and makes up the majority of their diet. They are only one of two North American rabbit species known to dig their own burrows, but sometimes they inhabit burrows abandoned by other species. Pregnant females dig natal burrows (which are separate from residential burrow systems) where they give birth to and nurse their young. Breeding typically occurs from February through July. They communicate with one another via vocalizations, indicating some sociability. Pygmy rabbits are an important prey species; therefore, predation is the primary cause of mortality, reaching up to 50 percent during the first five weeks of life. Predators include weasels, coyotes, badgers, bobcats, foxes, and birds of prey. 

Geographic Distribution and Population Changes
This species is native to the United States and occurs throughout the Great Basin, spanning sections of Washington, Idaho, Wyoming, Oregon, Utah, California, Nevada, and Montana. Washington subpopulations became genetically isolated from the core species' range some 10,000 years ago.

https://ecos.fws.gov/ecp0/pub/speciesRecovery.jsp?sort=1

Pygmy rabbits are found in a variety of semiarid shrub habitats and are not distributed continuously across their range. Because of their elusive behavior, it is difficult to evaluate all populations in the wild. Once an area is found to contain pygmy rabbits, they are usually dispersed throughout the valley in reasonable numbers. However, little is known about their dispersal potential, and consequently, their current population trend is unknown.

Listing Date and Type of Listing
Brachylagus idahoensis was first enlisted on the IUCN Red List as vulnerable in 1994. However, in 2001, it was emergency listed as endangered and received final endangered status in 2003. A recovery plan was implemented in 2012 with efforts to reclassify the species as threatened.

Cause of Listing and Main Threats to Existence
Because the pygmy rabbit is so dependent on sagebrush for food and shelter, it is particularly sensitive to habitat loss. Fragmentation and degradation of native shrub steppe habitat is the primary reason for their long-term population decline, though not the only reason. Higher frequency of fires due to an increase of invasive cheatgrass, as well as isolation of populations by habitat fragmentation have contributed to their decline in numbers. Once the populations decreases below a threshold number, many factors can increase the risk of extirpation, such as predation, disease, or loss of genetic diversity.

Description of Recovery Plan
The goal of the Federal recovery plan is to ultimately remove the Columbian Basin pygmy rabbit from the Federal List of Endangered and Threatened Wildlife and Plants. This would be achieved long-term by increasing population numbers, distribution, and security of wild subpopulations in the Columbia Basin. The recovery plan is as follows:

1. Manage partially controlled field-breeding

2.  Survey, monitor, and assess free-ranging populations

3. Reestablish free-ranging subpopulations within their historical distribution

4. Protect free-ranging pygmy rabbits

5. Manage habitats to support stable, self-sustaining subpopulations 

6. Pursue conservation agreements with landowners and managers of intervening properties within the population's historical distribution

7. Inform the general public to address concerns and increase support for recovery efforts

8. Secure funding for recovery

9. Revise the Federal Recovery Plan to facilitate implementation

It is currently not possible to estimate a date of recovery because few surviving Columbia Basin pygmy rabbit populations are established in the wild. Captive breeding programs have been implemented in the past, but the wild pygmy rabbits used to found the captive population suffered from inbreeding depression. They were not able to produce viable offspring for reintroduction, so the purebred captive individuals had to be intercrossed with pygmy rabbits outside the Columbia Basin to preserve genetic diversity Another conservation method used was conservation of the greater sage brush. Because of the rabbits' dependence on the sagebrush, they would likely benefit from its restoration.

What Can You Do?

https://www.wired.com/2011/04/pygmy-rabbits-reintroduced/

To save the Columbia Basin Pygmy rabbit, we can increase awareness for recovery efforts and help with funding recovery plans such as breeding programs by making donations. We can help by protecting the Sheldon and Hart Mountain National Wildlife Refuges as part of the Beyond the Boundaries program, which can be found at: http://refugeassociation.org/wildlife/mammals/pygmy-rabbit/.

Sources:
http://www.iucnredlist.org/details/2963/0
https://www.fws.gov/wafwo/articles.cfm?id=149489590
https://ecos.fws.gov/ecp0/pub/speciesRecovery.jsp?sort=1
http://washingtonslittlefriends.blogspot.com/p/profile.html