Postfire grazing management effects on mesic sagebrush-steppe vegetation: Mid-summer grazing

摘要

Postfire livestock grazing management in the higher-elevation, mesic portions of the sagebrush steppe lacks a firm scientific foundation to support decision making. Following a prescribed fire conducted in fall 2002, we evaluated effects of different lengths of rest from mid-summer (July) cattle grazing on postfire ground cover and plant species diversity responses in mesic sagebrush steppe. Treatment levels representing no rest; 1, 2, or 3 years of rest from grazing, and a burned-ungrazed control, all had similar effects on graminoid and forb basal cover and plant species density and frequency. However, grazing reduced litter cover and increased bare ground exposure relative to the control. A synthesis of this and other case studies of postfire grazing in sagebrush steppe indicates multiple years of rest from grazing are not strictly necessary for effective and timely recovery of vegetation but, on sloping terrain where potential runoff and erosion hazards exist, multiple years of rest may be needed to promote sufficient rates of litter recovery and reduction of bare ground exposure. These findings support calls for increased flexibility in policies governing postfire grazing management on federal lands and, as such, could influence ecosystem health, livestock production and other services throughout much of the western Us.