The Hells Canyon Initiative is a state, federal, and private partnership to restore Rocky Mountain bighorn sheep (Ovis canadensis canadensis) in the Hells Canyon area of Oregon, Idaho and Washington. This plan describes project goals and objectives, the background and current condition of bighorn sheep and bighorn sheep management in Hells Canyon, and actions to be accomplished under the Hells Canyon Initiative. The plan was written by and will be implemented by the Hells Canyon Bighorn Sheep Restoration Committee, a committee operating under a Memorandum of Agreement signed by the states of Oregon, Idaho and Washington, the Wallowa-Whitman National Forest, the Bureau of Land Management, and the Foundation for North American Wild Sheep.
The Hells Canyon project area encompasses over 5.5 million acres in the Snake River drainage from the mouth of the Clearwater River, Idaho, south to Brownlee reservoir. Elevations range from 800 ft. in the Snake River Canyon to over 9,000 ft. in the Seven Devils, Idaho and Wallowa Mountains, Oregon. Over 1.3 million acres (24%) of the project area is potential bighorn sheep habitat, 68% of which is publicly-owned, primarily managed by the U.S. Forest Service. Other public land managers are the states of Idaho, Oregon and Washington, and the Bureau of Land Management.
Bighorn sheep were historically abundant, but were extirpated from Hells Canyon and the surrounding area by 1945 by a combination of competition for forage with domestic livestock, introduced diseases, and over-hunting. Bighorn sheep reintroductions and habitat management have been ongoing since 1971. Three hundred twenty-nine bighorn sheep from 9 source populations have been released into the project area. Currently, about 700 bighorn sheep occur in 14 herds. The population has increased in size at an average annual growth rate of 7%. Disease transmitted by livestock and unknown sources has been an important factor limiting population growth. At least 7 disease epidemics have reduced the annual population growth rate by about 40%.
Considerable bighorn sheep habitat, particularly summer range, exists in the Wallowa, Seven Devils, and Blue Mountains portion of the project area. Extensive year around habitat occurs in the low elevation Snake River canyon grasslands. Habitat improvement projects completed to date include development of 44 water sources, pasture cultivation for bighorn sheep, treatment of over 70,000 acres with prescribed wildfire since 1992, and placement of salt and medication blocks in bighorn sheep herd areas. Interagency noxious weed projects are active and ongoing. Several U.S. Forest Service domestic sheep allotments have been vacated since 1990. Public land domestic sheep allotments currently occur at 5 locations within the project area.
Under the Hells Canyon Initiative, state and federal agencies will increase efforts to reintroduce bighorn sheep and manage habitat and populations to establish new herds and increase the size of existing herds. Information on bighorn sheep ecology and factors limiting population size will be collected, evaluated, and incorporated into management. The area will serve as a model for bighorn sheep restoration at a landmark level and provide information and techniques for use in bighorn sheep restoration and management in other areas.