Tracing Vegetation Responses to Drought Across Scales: Progress and Future Directions

Drought exacerbates vegetation water deficit, increasing the risk of mortality, disrupting carbon cycling and energy exchange processes, and thereby weakening ecosystem services and functions. Although many studies have examined how vegetation responds to drought, a comprehensive understanding that integrates multiscale responses with post-drought adaptation mechanisms remains limited. Using bibliometric analysis and a systematic synthesis of the literature, we first summarize publication trends, major disciplines, leading countries and institutions, keyword evolution, and the principal approaches used to investigate vegetation responses to drought. Secondly, we systematically examine vegetation responses across four interconnected levels—physiology and biochemistry, canopy structure, phenology, and carbon sequestration—while tracing the full trajectory from drought-induced damage to post-drought recovery and adaptation within this multiscale framework. Thirdly, we further discuss the regulatory roles of key mediating factors and identify major future research directions. Results show that vegetation responses to drought are continuous but scale dependent, progressing from physiological disruption to canopy degradation, phenological shifts, and reduced carbon sequestration. Their magnitudes vary across vegetation types, hydroclimatic regions, drought characteristics, and antecedent conditions. Post-drought recovery is governed by legacy effects, resistance and resilience, while key mediating factors may either amplify or buffer drought impacts. However, these interactions and their scale-dependent mechanisms remain poorly represented in current ecosystem models. Future research should be focused on clarifying the mechanisms underlying non-conventional drought events, distinguishing their impacts on vegetation, and developing impact-oriented drought monitoring approaches. Particular attention should be given to the micro-level mechanisms of vegetation changes, and multiscale integrated research based on diverse data sources and methods should be promoted to better predict and assess the impacts of future climate change on ecosystems.