Soil Erosion and Significance for Carbon Fluxes in a Mountainous Mediterranean-Climate Watershed

In topographically complex terrains, downslope movement of soil organic carbon (OC) can influence local carbon balance. The primary purpose of the present analysis is to compare the magnitude of OC displacement by erosion with ecosystem metabolism in such a complex terrain. Does erosion matter in this ecosystem carbon balance? We have used the Revised Universal Soil Loss Equation (RUSLE) erosion model to estimate lateral fluxes of OC in a watershed in northwestern Mexico. The watershed (4900 km²) has an average slope of 10° ± 9° (mean ± SD); 45% is >10°, and 3% is >30°. Land cover is primarily shrublands (69%) and agricultural lands (22%). Estimated bulk soil erosion averages 1350 Mg·km⁻²·yr⁻¹. We estimate that there is insignificant erosion on slopes