Vegetation Response on Allotments Grazed Under Rest-Rotation Management

Abstract

The effects of grazing management systems on plant communities in the Great Basin are largely unknown. This study is a quantitative description of the response of vegetation from 1973 to 1983 on the Goldbanks and Pueblo Mountain cattle allotments in northern Nevada managed under a 3-pasture rest-rotation grazing system. Shrub canopy cover, basal-area cover of herbaceous species, and frequency of occurrence of all species were used to estimate change in vegetation characteristics on macroplots representing 9 community types. Forage use was heavy in all years and averaged 65% in June, 75% in July and August, and 80% in October. Sandberg bluegrass [Poa sandbergii Vasey] and sagebrush [Artemisia spp. L.] were the most responsive species. Long-term increases or decreases in frequency and cover of desirable grasses were found on very few sites. Perennial forbs increased on a number of sites. Short-term changes in frequency and cover of Sandberg bluegrass and in frequency of sagebrush seedlings and young plants were attributed to a sequence of dry and wet years and to level of competition from herbaceous species. Frequency data indicated more significant changes in species composition than did cover data. The management system, forage utilization levels imposed, and climatic conditions present maintained prestudy range condition throughout the study on most sites at Pueblo Mountain. An increase in frequency and cover of Wyoming big sagebrush [A. tridentata wyomingensis Beetle] and a decrease in the cover of desirable grasses at Goldbanks suggest a downward trend in range condition on some sites where either Thurber needlegrass [Stipa thurberiana Piper] or bluebunch wheatgrass [Agropyron spicatum (Pursh) Scribn. & Smith] is the potential dominant grass.