A good range inventory showing the plant species, the soils, the topographic conditions, and the rainfall is essential to determining the numbers of livestock that can be supported on any range. There are many management techniques, in addition to control of livestock numbers that can be used to influence the range condition. The increased importance of wildlife production and management on the western range also can be readily illustrated. In the 1940, range management emerged as a science--a hybrid combination of animal husbandry, agronomy, botany, and basic ecology. By use of trend indicators over a several-year period, adjustments can be made in management techniques to correct undesirable changes in the vegetation that may lead to reduced productivity. The traditional approach to vegetation surveys on rangelands is often described as "dynamic ecology," the central concepts of which are "succession" and "climax." The key to understanding the habitat limitations for range livestock is the vegetation.