Fire effects in sagebrush communities - the good, the bad, and the in-between

Periodic to infrequent fire in the 71 million ha sagebrush ecosystem of North America historically shifted dominance from sagebrush to herbaceous vegetation, and limited conifer encroachment. Large wildfire years in recent decades, the proliferation of fire-adapted invasive annual grasses, and the decline of sagebrush habitat and associated wildlife have resulted in calls for fire exclusion in sagebrush communities. However, the role and effect of fire in sagebrush communities varies by a host of factors. We synthesized the literature on fire in sagebrush communities to examine how and why fire effects vary and identify the effects of fire on wildlife and biodiversity, and how restoration efforts influence fire effects. Communities in good condition pre-fire are likely to be in good condition post-fire and vice-versa. Cooler, wetter communities are more resilient and periodic fire is essential for limiting conifers in these communities. In hotter, drier communities, fire has a greater potential to promote invasive annual grasses. Post-fire restoration that establishes native vegetation can mediate negative impacts and promote positive outcomes, but are less likely to be successful in the hotter, drier communities. Infrequent fire, especially if it creates a mosaic of different aged burns and unburned areas, is vital to the sustainability of cooler, wetter sagebrush communities, promoting biodiversity and wildlife, but invasive plants and more frequent fire have made fire detrimental in hotter, drier communities. Variables influencing fire effects can be used to prioritize areas for wildfire suppression and pre- and post-fire treatments to improve resilience and limit annual grass invasion.