Vegetation Responses to Long-Term Sheep Grazing on Mountain Ranges

Some high-elevation summer ranges in southwestern Utah are characterized by a dominance of grass and low-value forbs. A reference area of forb dominance provides a striking contrast to these grass ranges. The reference area has a greater number of total species and a greater number of forbs. Production (above-ground live biomass) is nearly 2 times as great in the reference area as in the surrounding pastures. Production of desirable species in the reference area is greater than the production of desirables, intermediates, and least desirables in the surrounding pastures. It is suggested that the grass dominance on these ranges is due to a long and persistent history of exclusive sheep grazing.