Effects of Fire and Groundwater Extraction on Alkali Meadow Habitat in Owens Valley, California

Abstract

Abstract Alkali meadow habitat—a groundwater dependent ecosystem—is rare in California, and its response to fire has not been documented. We sampled vegetation in this habitat across a pumping-induced depth-to-water (DTW) gradient immediately before, then eight weeks after, a summer wildfire. After the fire in the burned area, we documented vigorous re-growth of native perennial grasses in areas of shallow groundwater but no re-growth of shrubs. The dominant grass Sporobolus airoides flowered in the shallow end of the DTW gradient but never advanced beyond vegetative phenology (leaves) in the drawn-down end. DTW explained 77% of the grass cover variance in the post-fire burned area, and 87% and 94% of the grass cover variance in the pre-fire and post-fire unburned (control) areas, respectively. This suggests that post-fire re-growth was re-establishing a cover-DTW relationship already present before the fire. The principal short-term fire effect was the elimination of shrub cover due to apparent shrub mor...