Nonlinear Interactions and Spatial Heterogeneity of Ecosystem Service Transitions in an Ecologically Fragile Karst Region of Southwest China

Karst regions are ecologically fragile landscapes where land use transitions and human interventions significantly reshape ecosystem service value (ESV). This study investigates the Miaoling watershed in Southwest China-a pivotal ecological barrier-by integrating a value equivalent factor model with an optimized geographic detector to quantify ESV changes and their drivers from 2000 to 2020. Our results reveal substantial land conversions, particularly between forest, grassland, and cropland, leading to pronounced spatial heterogeneity in ESV. Mixed-use zones emerge as critical ecological bottlenecks where gains in ESV coincide with heightened environmental risks. Importantly, we uncover strong nonlinear interactions between climatic (NDVI, precipitation) and socioeconomic (primary industry output) factors, reinforcing the complexity of natural-human feedbacks in karst landscapes. This study offers new insights into the spatial targeting of ecological restoration and risk management and contributes a replicable framework for assessing ecosystem transitions in vulnerable environments.