Dynamic soil erosion in response to LULC changes in mountainous areas of southwest China over the last 40 years: A case study of the Erhai Basin in Yunnan province

Rapid urbanization and tourism development in Southwest China's mountainous regions have driven significant land use changes over 40 years, yet their ecological impacts on soil erosion remain understudied. Using the Modified Universal Soil Loss Equation (MUSLE), this paper examines the Erhai Basin as a representative case to assess anthropogenic activities and land use changes' effects on soil erosion dynamics from 1980 to 2020. Key findings: (1) Cropland decreased by 13.24% while construction land expanded 97.06%, mainly cropland converted to construction land and forest/grassland. (2) Soil erosion declined continuously, with 45.77% reduction in annual erosion modulus and 8.56% decrease in moderate-to-severe erosion areas. Severe erosion occurred on 16–25° slope cropland, with downstream regions as hot-spots.(3) Erosion modulus positively correlated with cropland/grassland/construction land changes, negatively correlated with forest/water body changes.(4) The most significant findings indicate that domestic tourists and urban populations positively affect soil erosion (throughput factor>0.294), while tourist attractions and construction sites show negative correlations (throughput factor<0.326). Land use type drives spatio-temporal heterogeneity in soil erosion (Q=0.226), with slope interaction being most influential (Q=0.597). Erosion mitigation evolved from limited early efforts to systematic engineering post-2000, with recent intelligent watershed management achieving high-quality conservation. This research provides universal insights for fragile mountainous ecosystems globally. • The spatial and temporal distribution of soil erosion was explored, with an overall decreasing trend and the rapid reduction occurring between 2000 and 2010. • Reveals the impact of urbanization and tourism development on soil erosion. • Reduction of cropland and increase in construction land mitigate soil erosion. • The link between the implementation of soil and water conservation policies and soil erosion was assessed.