Spatial Patterns and Controls on Wind Erosion in the Great Basin

The Great Basin of the western United States is experiencing dramatic increases in wildfire and Bromus species invasion that potentially accelerate wind erosion and plant community change. We used a wind erosion model parameterized for rangelands and standard ecological monitoring data sets collected at 10,779 locations from 2011 to 2019 to characterize potential wind erosion in the Great Basin, assess relationships between factors affecting wind erosion, and quantify effects of wildfire and invasive Bromus species on aeolian horizontal sediment flux, Q. There were 403 monitoring plots (∼3.7% of plots) with Q > 100 g m⁻¹ d⁻¹. Median values for the highest Q category (>100) ranged from 196.5 to 308.5 g m⁻¹ d⁻¹. Locations with Q > 100 g m⁻¹ d⁻¹ were associated with dry, low elevation areas of the Great Basin with low perennial grass and perennial forb cover, and with large bare gaps between plants. Areas with high perennial grass, perennial forb, and shrub cover had small Q (≤10 g m⁻¹ d⁻¹). Substantial wind erosion was predicted in areas that have experienced wildfires, but areas with multiple wildfires had a lower predicted probability of Q particularly as invasive Bromus species cover increased. Modeled Q was up to two orders of magnitude higher post-wildfire (median 44.2 g m⁻¹ d⁻¹) than in intact or annual grass-invaded regions of the Great Basin (median 0.4 g m⁻¹ d⁻¹). Our results reveal the complex interplay among plant community composition, wildfire, and the amount of bare ground controlling wind erosion on Great Basin rangelands.