|Investigating long-term trends in aeolian sediment transport in the Great Basin
|Year of Publication
|Treminio, R, Webb, NP, Edwards, BL, Faist, AM, Newingham, BA, Kachergis, EJ, Chappell, A
|International Conference on Aeolian Research
|Las Cruces, N.M. USA
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.