The Impact of Land Use and Vegetation Cover Changes on Soil Erosion in the Southwest Karst Region

This study investigates the impact of land use and vegetation cover changes on soil erosion in the Southwest Karst region from 2000 to 2020. The InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model was employed to estimate soil erosion, incorporating analyses of land use transition matrices and fractional vegetation cover (FVC) data. The findings reveal that severe erosion was the predominant erosion intensity; however, both its relative proportion and absolute area exhibited a declining trend. The proportion of severely eroded areas decreased from 92.14% in 2000 to 58.96% in 2020. Regarding land use changes, the expansion of forest and water bodies contributed to soil erosion mitigation, whereas the reduction in grassland and the increase in built-up areas potentially exacerbated soil erosion. Notably, an increase in vegetation cover significantly suppressed soil erosion, particularly within moderate slope ranges (8°-15°), where a 10% increase in vegetation cover reduced soil erosion rates by 18%-42%. Moreover, the study highlights that topographic gradients play a critical role in modulating the soil conservation effect of vegetation cover, with the regulating effect intensifying in a stepwise manner as slope increases. These findings provide a scientific basis for soil erosion control and ecological restoration in the Southwest Karst region. It is recommended that differentiated ecological restoration strategies be implemented across varying slope ranges to effectively mitigate soil erosion.