Post-fire vegetation communities in western Colorado

Abstract

Wildfire is a cause of disturbance on public lands, and post-fire treatments often include broadcast seeding of native and non-native seeds. We collected vegetation data from an area burned by a wildfire in western Colorado in 2012 and, where available, compared pre- and post-fire data. We sought to determine how dominant plant species responded to fire and to determine post-fire vegetation community dynamics as compared to a typical response as described in the floristic composition model. Seed mixes were chosen based on previously available vegetation and treatment data. We found that areas seeded with a native seed mix had increasing cover of native forbs, whereas areas seeded with a non-native mix did not. However, the cause of low forbs in areas seeded with non-natives is not clear. We also found several native plant species that recovered after the fire, while sagebrush was absent after fire. Surprisingly, cheatgrass (Bromus tectorum L. [Poaceae]) frequency did not increase after fire in areas where pre- and post-fire data were available.