|Spatial patterns and controls on wind erosion in the Great Basin
|Year of Publication
|Treminio, R, Webb, NP, Edwards, BL, Faist, AM, Newingham, B, Kachergis, EJ
|Society for Range Management: Rangelands Without Borders
The Great Basin, containing a large portion of the managed rangelands of the western United States, is experiencing disturbances due to wildfire and cheatgrass (Bromus tectorum) invasion that potentially accelerate wind erosion and plant community change. While these disturbances have been linked to increased wind erosion and dust emissions at local scales, no comprehensive study has investigated interactions between wildfire and invasive cheatgrass at the regional scale across the Great Basin. This study used a wind erosion and dust emission model (AERO) parameterized for rangelands to leverage standard monitoring datasets (e.g., BLM AIM) to: 1) characterize the magnitude of horizontal sediment flux — a measure of aeolian sediment transport (Q, g m-1 day-1) — at rangeland monitoring plots to identify eroding dust source regions, 2) describe the relationships between weather, soil, vegetation cover, geography, and disturbance and Q, 3) quantify effects of wildfire and invasive cheatgrass cover and structure on Q, and 4) identify thresholds in ground cover indicators used as inputs to AERO that can be used as benchmarks for wind erosion assessment across Major Land Resource Areas (MLRAs) comprising Great Basin. We found the Fallon-Lovelock Area (MLRA 27) had the highest and Snake River Plains (MLRA 11) the lowest average wind erosion indicated by modelled Q. Plant cover and precipitation were negatively related and measures of bare ground and canopy gap size distribution were positively related to Q. The probability of Q occurring was consistently high with invasive plant species cover but decreased with the number of fires associated with monitoring plots sampled in the Great Basin. Thresholds in indicators of vegetation cover varied with the level of Q within and between MLRAs, suggesting that when bare ground is greater than ~20 %, Great Basin rangelands are at risk of accelerated wind erosion.