Repeated fires reduce plant diversity in low-elevation Wyoming big sagebrush ecosystems (1984-2014)

Sagebrush is one of the most imperiled ecosystems in Western North America, having lost about half of its original 62 million hectare extent. Annual grass invasions are known to be increasing wildfire occurrence and burned area, but the lasting effects (> five years post-fire) that the resulting reburns have on these plant communities are unclear. We created a fire history atlas from 31 years (1984 to 2014) of Landsat-derived fire data to sample along a fire frequency gradient (zero to three fires) in an area of northern Nevada that has experienced frequent fire in this time period. 32% of our study area (13,000 km$^2$) burned in large fires (over 404 ha) at least once, 7% burned twice, and 2% burned three or more times. We collected plant abundance data at 28 plots (N=7 per fire frequency), with an average time-since-fire of 17 years. We examined fire’s effect on plant diversity using species accumulation curves, alpha-diversity (Shannon's dominance, Pielou's evenness and number of ...