Elevated aeolian sediment transport on the Colorado Plateau, USA: The role of grazing, vehicle disturbance, and increasing aridity

Dryland wind transport of sediment can accelerate soil erosion, degrade air quality, mobilize dunes, decrease water supply, and damage infrastructure. We measured aeolian sediment horizontal mass flux (q) at 100 cm height using passive aspirated sediment traps to better understand q variability on the Colorado Plateau. Measured q‘hot spots’ rival the highest ever recorded including 7,460 g m⁻² day⁻¹ in an off‐highway vehicle (OHV) area, but were more commonly 50‐2,000 g m⁻² day⁻¹. Overall mean q on rangeland sites was 5.14 g m⁻² day⁻¹, considerably lower than areas with concentrated livestock use (9‐19 g m⁻² day⁻¹), OHV use (414 g m⁻² day⁻¹), and downwind of unpaved roads (13.14 g m⁻² day⁻¹), but were higher than areas with minimal soil disturbance (1.60 g m⁻² day⁻¹). Rangeland q increased with increasing annual temperature, increased winds, and decreasing precipitation. Spatial modeling suggests that ~92‐93% of regional q occurs in rangelands versus ~7‐8% along unpaved roads. Four of the five largest road qvalues (n=33) measured were along roads used primarily for oil or gas wells. Our findings indicate that predicted future mega‐droughts will increase q disproportionately in disturbed rangelands, and potentially further compromise air quality, hydrologic cycles, and other ecosystem services.