Technical Abstract: Ecosystem management directed at restoring historical disturbance regimes may be inappropriate under modern conditions. Moderately grazing sagebrush plant communities with livestock, though not part of the historical disturbance regime, increased the tolerance of the perennial herbaceous vegetation to fire and promoted resistance to cheatgrass invasion. However, mimicking the historical disturbance regime of minimal large herbivore pressure and periodical fire promoted cheatgrass invasion. This study suggests that moderate levels of livestock grazing may be critical to protecting sagebrush plant communities and wildlife dependent on them.