Dynamic aeolian erosion evaluation and ecological service assessment in Inner Mongolia, northern China

Abstract

The spatiotemporal distribution and dynamic processes of aeolian erosion and desertification along with their ecological service assessments are still not clearly known at a regional scale, nor are the effects of wind force and topography upon soil losses. Inner Mongolia, China, is a typical and fragile region prone to severe and perennial aeolian erosion and desertification. Here we employed the Revised Wind Erosion Equation (RWEQ) to evaluate the aeolian erosion modulus (SL, kg m−2 yr−1) from 2010 through 2018 at the regional scale, in addition to determining and categorizing the erosion intensity according to standards of the Ministry of Water Resources of China (2007). We combined the erosion intensity with a gravity center migration model to delineate the migration path and extent of aeolian erosion, and then integrated the soil retention rate (F, %) in a trend analysis to clarify the variation in soil conservation. To quantify the effects of wind force (wf, dimensionless) and topography elevation (H, m) upon SL, the line constraint method was applied, while the aeolian desertification index (ADI, dimensionless) was used to quantify the magnitude of variation in desertification. The SL was constrained by the quadratic function of H, in that maxima for SL occurred at c. 1300 m, yet it was constrained by the power function of wf. Over time, the gravity center of tolerable erosion intensity underwent the most pronounced migration, followed by that for slight, severe, and moderate intensities. The F values declined from east to west Inner Mongolia, with a trend of maximum and mean F both increasing prior to 2015 yet decreasing afterwards. Correspondingly, ADI decreased prior to 2016 but increased afterwards. These findings clarify our understanding of the dynamic spatiotemporal distribution of aeolian erosion and intensity, and are valuable for guiding decision applications in sustainable development and soil conservation at regional scales.