Spatiotemporal Patterns of Cropland Abandonment and Its Nonlinear Effects on Water Yield in the Humid Lingnan Region, China: Implications for Environmental Sustainability

Cropland abandonment has become a widespread land-use transition under global socioeconomic transformation, with critical effects on regional ecosystem structure, service functions, and environmental sustainability. However, existing studies remain limited in explaining the long-term dynamics and nonlinear driving factors through which cropland abandonment affects water-related ecosystem services in humid regions. This study focuses on the Lingnan region, a typical humid area in southern China. Using the 30 m-resolution China Land Cover Dataset from 2000 to 2023 and a land-use trajectory-tracking method, this study identified the spatiotemporal patterns of cropland abandonment, coupled the InVEST water yield module with a Random Forest model to quantify changes in InVEST-simulated water yield, and identified underlying driving factors. According to the results, (1) abandoned cropland ranged from 8.90 × 10 4 to 7.23 × 10 5 ha, with a mean abandonment rate of 2.13%. Spatially, it exhibited a dispersed mosaic pattern with regional clustering, mainly distributed in low- and moderate-slope areas and gradually expanding toward more complex terrain conditions; (2) more than 92% of abandoned patches showed increased simulated water yield depth, with a multi-year mean of 769.87 mm, while localized decreases occurred on steep slopes where soil erosion may weaken the hydrological response; (3) climatic factors served as the dominant driving factors of simulated water yield changes, with annual precipitation contributing the most to model explanation (0.536), and all key variables exhibited nonlinear responses, indicating complex interactions between climatic conditions, terrain characteristics, and vegetation recovery processes. These findings provide quantitative evidence to better understand how cropland abandonment reshapes water-related ecosystem services in humid regions and support spatial governance strategies that coordinate food security, ecological protection, and environmental sustainability amid rapid urbanization.