Linking Drought Stress to Vegetation Stability and Recovery at the Global River-Basin Scale

Vegetation responses to drought play a central role in regulating land–atmosphere interactions, carbon cycling, and ecosystem stability, yet large-scale differences in vegetation resilience across river basins and climate regimes remain insufficiently characterized. This study examines drought-driven changes in vegetation stability and recovery at the global river-basin scale, combining historical observations from 2000–2023 with future projections for 2024–2099 under two climate scenarios (SSP245 and SSP585). Vegetation dynamics are assessed using satellite-derived leaf area index as an indicator of ecosystem condition, while meteorological drought, irrigation, and environmental controls are evaluated within a regression-based attribution framework. Results indicate that many major river basins exhibit weak precipitation control on vegetation dynamics, increasing exposure to drought stress, particularly in arid and semi-arid regions. Irrigation emerges as a key buffering mechanism, contributing between roughly one-fifth and one-half of vegetation resilience during pre-drought and drought phases. Short-term drought projections using machine-learning regression highlight pronounced sensitivity in evergreen and deciduous needleleaf forests, with wetlands and grasslands also showing elevated vulnerability under increasing water limitations. Differences in vegetation response are strongly ecosystem-dependent, reflecting contrasting elasticities to both climatic forcing and human water management.  The findings reveal substantial spatial heterogeneity in vegetation resilience across global river basins and emphasize the growing importance of irrigation in moderating drought impacts under future climate conditions. These results offer new insights into ecosystem-specific drought responses and provide a basin-scale perspective relevant for climate adaptation, water management, and ecosystem sustainability assessments.