Spatiotemporal Evolution and Synergy–Tradeoff Relationships of Ecosystem Services in Typical Karst Mountain Areas, China

Karst Mountain Areas (KMAs) are characterized by fragile geology, shallow soils, and high ecological sensitivity, rendering their Ecosystem Services (ESs) highly vulnerable to Land Use and Land Cover (LULC) change. However, the spatiotemporal evolution of ESs and the trade-offs and synergies among them remain poorly understood, particularly concerning the interplay between human activities and natural constraints in these complex landscapes. Taking the Wumeng Mountain Area (WMA) in southwestern China as a representative case, this study integrates multi-temporal LULC data (2000, 2010, and 2020) with the InVEST model to quantify the dynamics of four key ESs: Carbon Storage (CS), Habitat Quality (HQ), Soil Conservation (SC), and Water Yield (WY). An integrated analytical framework combining land use dynamic degree, intensity analysis, transition matrices, and grid-scale Spearman correlation analysis was developed to reveal ESs interactions. Results indicate that, despite substantial land use changes, most ES pairs exhibited synergistic relationships, and these synergies intensified from 2000 to 2020. The strengthened synergies, particularly among CS, SC, and HQ, are conducive to simultaneously achieving multiple ecological security goals, such as regional carbon sequestration, biodiversity conservation, and soil stability. However, the trade-offs observed between water yield and regulating services (CS, HQ) in 2000 highlight potential conflicts between ensuring water supply and enhancing other ecological benefits in fragile karst landscapes, offering a scientific caution for balancing water resource development with ecological protection. This study demonstrates that understanding ES interactions is not merely an ecological description but constitutes a critical scientific basis for optimizing land use and improving regional human well-being and sustainability.