Vegetation resilience to compound drought and heatwave events in China: Spatiotemporal patterns, drivers, and future risk

Compound drought and heatwave (CDHW) events are intensifying under global warming and pose growing threats to the stability of terrestrial ecosystems. However, vegetation resilience to CDHWs, its underlying drivers, and its future trajectory remain poorly understood across China. Here, we developed a Standardized Compound Drought and Heatwave Index (SCDHI) by coupling the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Temperature Index (STI), identified CDHW events using run theory, and quantified resistance and recovery of eight vegetation types based on MOD17A2H gross primary productivity (GPP). We then used an interpretable XGBoost-SHAP framework to identify dominant drivers and projected future resilience risk under SSP2–4.5 and SSP5–8.5 using bias-corrected CMIP6 data. Since the beginning of the 21st century, CDHW intensity, severity, peak magnitude, frequency, and duration have all increased significantly across China. Resistance showed a pronounced east-high–west-low pattern controlled primarily by event-period maximum temperature, whereas recovery declined from south to north under post-event precipitation control. Resilience also differed substantially among vegetation types: forests were the most resilient, jointly maintaining high resistance and recovery, while shrubland, grassland, and cultivated vegetation were intermediate, and alpine and desert vegetation were the least. Historically, resistance remained broadly stable, whereas recovery declined in most vegetation types. In contrast, future projections indicate widespread declines in resistance, while recovery remains stable or increases slightly. Resistance declines most sharply in the western interior, the principal future vulnerability region. Together, these findings show that the dominant dimension of resilience loss shifts over time, calling for region-specific adaptation pathways under intensifying climate change.