[Analysis of the Impact of Multi-scale Landscape Pattern Changes on Soil Erosion Risk in the Beijiang River Basin]

Soil erosion has become an increasingly serious environmental problem. A comprehensive understanding of high-risk areas and key drivers of soil erosion at different spatial scales is critical for developing effective soil erosion control strategies and optimizing land resource use. As a key factor influencing soil erosion， the impact of landscape patterns on soil erosion at different spatial scales has not been quantitatively analyzed. Using the Beijiang River Basin as a case study， this study investigates the spatiotemporal evolution of landscape patterns and soil erosion from 2000 to 2020. We used Geodetector and spatiotemporal geographic weighted regression to reveal the driving mechanisms of soil erosion at different spatial scales. The results indicate that： ① Soil erosion increased significantly in the northwest of the Beijiang River Basin， with the area of moderate， severe， and extremely severe erosion accounting for 40% between 2000 and 2020， mainly influenced by elevation and precipitation. In contrast， the erosion risk in the northern and central regions decreased， mainly due to vegetation restoration and soil and water conservation measures. ② Over the past 20 years， landscape fragmentation in the Beijiang River Basin has increased by 12%， with the highest fragmentation occurring in the northeastern and southern parts of the basin， which is expected to exacerbate erosion risks in the future. ③ The interaction effect of landscape fragmentation and vegetation cover on soil erosion was the most significant at the basin and county scales， and the interaction effect coefficient were 0.634 and 0.768， respectively， indicating that vegetation cover could help mitigate the erosion risk caused by fragmentation. ④ The driving factors of soil erosion showed significant spatial heterogeneity at different spatial scales， and the effects of terrain， landscape pattern， and vegetation coverage on erosion gradually increased with the thinning of scales. Specifically， at the watershed scale， the interaction intensity of landscape fragmentation and vegetation cover on soil erosion were 0.634 and 0.515， respectively， while at the township scale， the interaction between surface temperature and vegetation cover was the most significant， with an interaction effect coefficient of 0.516. Especially in the area of human activity density， the synergistic effect of climate factors and vegetation intensified the soil erosion risk. The research results revealed the high-risk areas and important driving factors of soil erosion at different scales in Beijiang River Basin， which can provide scientific basis for regional soil and water conservation and landscape optimization management at different scales.