Precipitation and Grazing Utilization Influence Postfire Herbaceous Plant Cover: A Meta-Analysis on Grazing After Fire

Following a wildfire or a prescribed fire, the recovery of rangeland vegetation is a critical consideration for restoring wildlife habitat, ecosystem services, and grazing value. Rangeland managers need to know when to resume grazing after fire to conserve rangeland resources and accomplish management objectives. To shed light on this issue, we conducted a meta-analysis of published research investigating the role of grazing after fire on vegetation recovery. Our search of two scientific databases found 18 articles with sufficient information to be comparable, mostly from the western US. To compare effect sizes, we conducted a meta-regression using moderators of precipitation, grazing utilization, fire season, years deferred from grazing, fire severity, and type of grazing animal, among others. We found that grazing within a few years after fire slightly reduced perennial grass cover compared with ungrazed areas, but type of grazing animal did not matter. Increasing precipitation and decreasing grazing utilization moderated this reduction in cover. Perennial grass cover in grazed plots decreased slightly as years after the fire increased. Resting an area from grazing after fire had no effect on perennial grass cover. Grazing after fire reduced annual grass cover compared with ungrazed areas and varied depending on precipitation and grazing utilization. Native forb cover was not affected by grazing after fire, though forb cover increased with spring fire and decreased with summer fire. In our analysis, grazing within a few years after fire did not affect herbaceous production. Our work provides a synthesis of effects on vegetation of grazing after fire and describes gaps in our current knowledge. We recommend including information on livestock management, including timing and intensity of grazing and season and duration of rest in future studies.