Desert ranges of the Great Basin area support about 9 million cattle and sheep for 5 to 6 months each winter. Many of these same ranges are used by cattle year-long.
If forage is not available on desert ranges, livestock have to be wintered on farmsteads or in feedlots after they are forced from the mountains and foothills by snow. Since feeding during the winter is expensive and reduces the economic efficiency of the range livestock operation, there is real advantage in properly managing the desert ranges and conserving the supply of forage for winter grazing.
Managing desert ranges for the greatest productivity requires a basic knowledge of the physiological reaction of plants to grazing. Knowledge of the effects of various grazing intensities at the different seasons of the year is necessary to establish proper management practices. Desert vegetation generally grows only during the spring and is in a state of dormancy during the remainder of the year. Thus, the influence of defoliation on plant physiology is more pronounced at one season than another.
The nutritional intake of grazing animals depends on the chemical composition of the available forage species and the grazing intensities. Most desert forages are low in nutrients in fall and winter because of their long period of dormancy. Heavy grazing also may decrease their nutritional value because coarser material is consumed.
Changes in vigor generally precede changes in the plant composition; therefore, vigor measurements can be a useful tool to the range manager in predicting initial changes in plant composition. Changes in vigor, however, are difficult to detect and are useful only to the degree that they can be measured accurately.
Because there is a history of range abuse throughout the western states, it is not only important for the land manager to understand how improper use may affect the condition of the range but also to understand how management may affect the recovery of range plants from a lowered state of vigor. The recovery rate of abused desert ranges is slow because of low precipitation and a limited growing period. This is an extremely important consideration in their management.
The primary purpose of this study was to determine the effects of season and intensities of herbage remove! on the phenological and chemical response of major desert species of the Great Basin and to determine the rate of recovery of plants in various states of lowered vigor.
Cook, C. Wayne, "Effects of Season and Intensity of Use on Desert Vegetation" (1971). UAES Bulletins. Paper 351.