LIVESTOCK GRAZING AND HABITAT FOR A THREATENED SPECIES - LAND-USE DECISIONS UNDER SCIENTIFIC UNCERTAINTY IN THE WHITE MOUNTAINS, CALIFORNIA, USA

The North Fork of Cottonwood Creek, in the White Mountains, Inyo Natio nal Forest, California, is a critically important refuge for the Paiut e cutthroat trout (Oncorhynchus clarki seleniris), a federally listed threatened species. Habitat for these fish appears to be limited by ex cessive levels of fine sediment in the channel. and livestock grazing of riparian meadows has been implicated in delivery of sediment to the channel. However, the relationships between land use and sediment yie ld have not been conclusively determined, in large part because there are no historically ungrazed sites to serve as long-term controls. Acc ordingly, land-use decisions must be made under scientific uncertainty . To reduce erosion and sedimentation in the stream, the Forest Servic e spent approximately US$260,000 from 1981 to 1991 to repair watershed damage from livestock grazing, prevent livestock from traversing stee p banks, and limit livestock access to the channel. Throughout this pe riod, livestock grazing has continued on these lands, yielding less th an $12,000 in grazing fees. In revising its Allotment Management Plan for the basin, the Forest Service rejected the ''no-grazing'' alternat ive because it was inconsistent with its Land and Resource Management Plan, which specifies there is to be no net reduction of grazing.