Climate-mediated associations between landscape fragmentation and metropolitan forest resilience in subtropical China

Abstract

Forest ecosystems are increasingly exposed to climatic and anthropogenic disturbances under accelerating global change, making their resilience crucial for sustaining ecological functions. While resilience has become a key concept in forest management, its associations under combined pressures of climate stressors and fragmentation remain insufficiently understood, especially in metropolitan forested landscapes. We quantified and mapped forest resilience in the Core area of the Wuhan Metropolitan Region (CWMR), a rapidly urbanizing region in subtropical China, from 2004 to 2023, and investigated the associations between climatic factors, landscape fragmentation, and spatial patterns of forest resilience. Forest resilience was quantified using the lag-1 temporal autocorrelation (TAC) of normalized difference vegetation index (NDVI) time series, based on critical slowing down theory. Key climatic factors associated with forest resilience were first identified using eXtreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP). Structural equation modeling (SEM) was then used to examine the direct and indirect associations among landscape fragmentation, climatic factors, and forest resilience. We found that 60.54% of focal forests experienced a decline in resilience over the past two decades, with an average annual reduction of 0.0046. XGBoost and SHAP analyses identified potential evapotranspiration and land surface temperature as important climatic predictors associated with forest resilience, with variability in potential evapotranspiration showing a stronger association than its long-term mean. Structural equation modeling revealed that patch shape complexity, indicative of stronger edge effects, exhibited the strongest associations with forest resilience through both direct pathways and indirect pathways linked to climatic conditions, highlighting their potential role in amplifying atmospheric drought stress. Our findings reveal a critical role of forest landscape fragmentation and climate interactions in regulating vegetation resilience. These results highlight the urgent need for adaptive forest management, such as optimizing patch edges and regulating forest microclimates, to support the persistence of metropolitan forest under rising warm-drought climate conditions.