Investigating long-term trends in aeolian sediment transport in the Great Basin

Authors: TREMINO, RON - New Mexico State University; Webb, Nicholas - Nick; EDWARDS, BRANDON - New Mexico State University; FAIST, AKASHA - University Of Montana; Newingham, Beth; KACHERGIS, EMILY - Bureau Of Land Management; CHAPPELL, ADRIAN - Cardiff University

Submitted to: International Conference on Aeolian Research
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2023
Publication Date: 7/14/2023
Citation: Tremino, R., Webb, N.P., Edwards, B., Faist, A., Newingham, B.A., Kachergis, E., Chappell, A. 2023. Investigating long-term trends in aeolian sediment transport in the Great Basin. International Conference on Aeolian Research. Abstract.

Interpretive Summary: Wildfire and invasive species encroachment can change plant communities which also affects the occurrence of wind erosion. The interactions among wilfire, invasive species, plant communities and wind erosion are not well understood at large geographic scales. We investigated these interactions across Major Land Resource Areas (MLRAs) of the Great Basin by using a wind erosion model and standardized datasets collected by the Bureau of Land Management Assessment, Inventory and Monitoring Strategy. We characterized wind erosion to identify dust sources and thresholds in ground cover, describe relationships among vegetation cover indices and wind erosion, and quantified the how wildire and cheatgrass cover influence wind erosion. High rates of wind erosion occurred in the northwestern portion of the Great Basin across the Owyhee High Plateau (MLRA 25) south to the Fallon-Lovelock Area (MLRA 27).We found indices of vegetation cover were negatively related and indices of bare ground were positively related to wind erosion. The probability of sediment transport was consistently high with increased invasive species cover but the probability decreased with number of fires. Finally, results suggest that when bare ground is greater than ~28 %, Great Basin rangelands are at risk of accelerated sediment transport

Technical Abstract: Wildfire and cheatgrass (Bromus tectorum) invasion are changing plant communities in the Great Basin of the western United States. Feedbacks between wildfire and cheatgrass invasion are linked to increased sediment transport at local scales, yet their regional-scale interactions are still poorly understood. We investigated long-term trends in modeled sediment transport responses to wildfire frequency and cheatgrass invasions in the Great Basin. We used the Aeolian EROsion (AERO) sediment transport model and the characteristics of 10,779 monitoring plots established by the Bureau of Land Management Assessment, Inventory, and Monitoring (AIM) program in rangeland across Major Land Resource Areas (MLRAs) comprising the Great Basin to: 1) characterize horizontal sediment flux, Q (g m-1 day-1) to identify dust sources and thresholds in ground cover, 2) describe the relationships among vegetation cover indices and Q, and 3) quantify effects of wildfire and invasive cheatgrass cover and structure on Q. Large modelled sediment transport rates occurred in the northwestern portion of the Great Basin across the Owyhee High Plateau (MLRA 25) south to the Fallon-Lovelock Area (MLRA 27). Plant cover indices were negatively correlated and measures of bare ground were positively correlated with modelled sediment transport. The probability of sediment transport was consistently high with increased invasive plant species cover but the probability decreased with the number of fires associated with monitoring plots sampled in the Great Basin. Overall, results suggest that when bare ground is greater than ~28 %, Great Basin rangelands are at risk of accelerated sediment transport.