By the 1970s and 1980s, a century of intense cattle grazing had reduced much of the riparian vegetation along stream banks in the Trout Creek Mountains and elsewhere in the Great Basin. As a result, stream banks were eroding and upland vegetation was encroaching into riparian zones. Aspen populations declined as grazing cattle eliminated young trees, decreasing shade over streams and raising water temperatures. These conditions put the rare Lahontan cutthroat trout population at risk. Since the Lahontan was officially designated as a threatened species, environmental groups began advocating the cancellation of grazing permits in the Trout Creek Mountains.