Rangeland Resources: Changing Uses and Productivity
B. Delworth Gardner
Rangeland in the United States, particularly in the West, has been and increasingly continues to be a resource of tremendous value to the nation. Rangeland may consist of natural grassland, savannas, deserts, shrubland, tundra, alpine plant communities, coastal marshes, wet meadows, and introduced plant communities managed like rangeland ( U.S. Department of Agriculture, 1988b). Rangeland--much of it privately owned--produces native vegetation such as grasses, grasslike plants, forbs, and shrubs. This land is suitable for grazing or browsing by domestic livestock and wild animals.
U.S. forests and rangeland provide forage and browse for more than 70 million cattle, 8 million sheep, 55,000 wild horses and burros, 20 million deer, 400,000 elk, and 600,000 antelope ( Darr, n.d.). The quantity of livestock grazing is reckoned in animal-unit-months. An animal-unit-month (AUM) of grazing is approximately the quantity of forage needed to maintain a mature cow for one month. AUMs produced on private rangeland represent nearly 86 percent of the total forage consumed by livestock nationwide. Pri