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Increased leaching of selenium into the watershed from agricultural practices may be impacting fish and wildlife that use these waters. Waterborne selenium concentrations of 2 parts per billion or greater should be considered hazardous to the health and long-term survival of fish and wildlife populations due to the high potential for food-chain bioaccumulation, dietary toxicity, and reproductive effects. In some cases, trace amounts of selenium may lead to bioaccumulation and toxicity even when total waterborne concentrations are less than 1 part per billion (Ixmly, 1993). Selenium concentrations in the Gunnison River downstream from Delta ranged from 4 to 10 parts per billion in 1988. Currently, studies are being done to determine what effect will be seen in native fish that use waters with high selenium concentrations. It is thought by some researchers that native fish may have a higher tolerance for selenium than some other fish species because they evolved in an area with higher background levels of selenium. Other endangered or threatened species that have been confirmed to use the Gunnison River or its floodplain include the bald eagle (Haliaeetus leucocephaha), peregrine falcon (Falco peregrinus), and possibly the whooping crane (Gros americana). The bald eagle is a fairly common winter resident and historically nested in area river bottoms. Food sources in the area include waterfowl, fish, rabbits, and carrion. The rivers are the primary focus of activities, although the eagles do feed and roost away from the river occasionally. Sandhill cranes frequent the Gunnison Basin during migration and experimentally introduced whooping cranes accompany these migrations between Idaho and New Mexico. This introduction experiment has ended and the whooping cranes in these flocks are not reproducing so their small numbers will gradually disappear from the Gunnison Basin. The peregrine falcon nests in the Black Canyon of the Gunnison National Monument and along the Colorado River downstream from the Gunnison River confluence. One endangered bird species-the southwestern willow flycatcher (Empidomar traillil ewmus)- and two birds that are candidates for listing-the black tern (Chlidonias niger) and the white- faced ibis (Plegadis child)--are considered to possibly use the Gunnison River Basin. An endangered plant, the clay-loving wild buckwheat (Eriogonum pelinophilum), and a threatened plant, the Uinta Basin hookless cactus (Sclerocactus glaucus), occur in scattered desert uplands in the Gunnison Basin. The Brandegee milk-vetch (Astragalus brandeget), a candidate plant species occurs in the upper Gunnison Valley in Gunnison County. Impacts The historical range of endangered fish species in the Colorado River Basin has been fragmented by construction of dams and diversions that serve as barriers to fish movement. Under the No Action Alternative, this condition would continue on the Gunnison River unless a fish passageway was constructed under another program. Under No Action a self-sustaining population of endangered fish would be less likely to develop in the Gunnison River. Under No 29