Spatiotemporal evolution and driving factors of ecosystem health in the Poyang lake region under compound pressures

Abstract Revealing the mechanisms underlying ecosystem health evolution in large river-connected lakes under intensive human activities is essential for adaptive management. However, existing studies primarily focus on ecological state changes or individual driving factors, with limited attention to the continuous process linking engineering disturbance, ecological response, and societal feedback. This study constructs an integrated assessment framework combining the Pressure-State-Response (PSR) model with obstacle degree analysis, applying it to 13 counties in the Poyang Lake Region (PYLR) across the Three Gorges Project (TGP) lifecycle from 1995 to 2022. By combining entropy weighting, the Comprehensive Ecosystem Index (CEI), obstacle factors, and temporal trend analysis, we identified the spatiotemporal patterns of ecosystem health and its dominant drivers. Results show that the CEI followed a V-shaped trajectory of decline, trough, and recovery. The degradation phase was associated with compound stresses arising from hydrological regulation and internal socioeconomic expansion. Conversely, the recovery phase was characterized by an anthropogenic compensation effect, reflecting a functional transition of socioeconomic development from environmental pressure to ecological response. Spatially, the CEI exhibited a “high-east, low-west, strong-north, weak-south” pattern, while regional differences in recovery trajectories indicated heterogeneous response capacities across the PYLR. This study provides evidence for the dynamic hydro–social interactions underlying ecosystem health evolution and offers a transferable framework for assessing and managing human-impacted lake systems.