Livestock have done more damage to the Earth than the chainsaw and bulldozer combined. Not only have livestock been around longer than developers, miners, and loggers, but they have been grazed nearly everywhere. On mostly arid public lands, hundreds of thousands of non-native livestock (including cattle, sheep, goats and horses) trample vegetation, damage soil, spread invasive weeds, pollute water, steal forage from native wildlife, and even contribute to global warming. 1
Livestock grazing in riparian (streamside) areas--especially in the arid American West--causes immeasurable damage to riparian resources, including the loss of fish and wildlife habitat, soil erosion, and diminished water quality and quantity, leading to almost irreparable damage to ecosystem and watershed integrity.
Livestock grazing occurs not only on the "tree-free" landscapes in the American West, but also in many forested areas. In addition to the proliferation of roads, the scourge of logging and the exclusion of fire, livestock grazing plays a major role in creating unhealthy forests.
1. Livestock account for 15 to 20 percent of total global methane emissions. Robbins, J. 2001. THE FOOD REVOLUTION. Conari Press, Berkeley, CA: 267 (citing A. Durning and H. Brough. 1991. Taking stock: animal farming and the environment. Worldwatch Paper 103 (July 1991)).