It is also the most widespread of the federally subsidized, private commercial practices operating on public lands, occurring on 270 million acres of rangeland managed by the federal government.16 Livestock grazing exacts a terrible toll on wildlife and its habitat, changing the species composition of native ecological communities and significantly impacting riparian areas. Grazing strips the banks of rivers and streams, which in turn leads to erosion and degradation of aquatic ecosystems. For example, many ranchers try to kill predators or species that may compete with livestock for food. These efforts have been so successful that many predators, such as the mountain lion, wolf and bear, have been extirpated from a majority of their range. Mining Mining significantly impacts ecosystems by destroying habitat and polluting and degrading streams and waterways.
Mining also leads to road building and surface mining, which destroy the surface ecosystem.
In addition, mining requires a large amount of underground material to be brought to the surface. For example, a northern Idaho gold mine has been leaking toxic cyanide into a tributary of the South Fork Salmon River, poisoning the breeding grounds of the threatened chinook salmon.19 Road Building Road building associated with agriculture, logging, mining and urban development seriously impacts ecosystems in a number of ways. Dirt roads, which are usually built in forest or mining operations, cause erosion and landslides, and degrade water quality in streams and rivers. In addition, when roads cut through an ecosystem, further habitat degradation and fragmentation results. Finally, the introduction of roads in the wilderness increases the chance of species being hit by cars or killed by legal or illegal hunting or trapping.