Drivers of Ecosystem Stability Differ with the Intensity of Extreme Climatic Events

Abstract. This study investigates how the dominant drivers of ecosystem stability metrics vary across gradients of hydroclimatic extremity. While previous studies have documented the impacts of droughts and heavy rainfall on ecosystem functioning and resilience inferred from stochastic fluctuations, less attention has been given to whether the relative importance of climatic, biotic, and landscape controls changes systematically under different levels of climatic stress. To address this question, we quantified vegetation resistance and event-scale recovery responses and compared the contributions of meteorological, biodiversity, and topographic factors across a global range of hydroclimatic conditions. We find that under normal to moderately dry conditions, vegetation stability metrics are primarily associated with meteorological variables, particularly temperature and precipitation, consistent with earlier global assessments. Under severe and extreme drought conditions, resistance decreases markedly across most regions, whereas recovery responses exhibit weaker and more spatially heterogeneous changes. Importantly, in sparsely vegetated ecosystems such as grasslands and open shrublands, the relative dominance of drivers shifts from climatic to biodiversity and topographic factors under intensified drought stress, indicating context-dependent regulation of ecosystem stability. Deciduous needle-leaf forests show consistently low resistance and recovery capacity across climatic regimes, suggesting elevated sensitivity to hydroclimatic variability. Overall, our findings demonstrate that ecosystem stability under climatic extremes cannot be explained solely by meteorological forcing and highlight the increasing importance of biodiversity and landscape heterogeneity in shaping stability responses under intensifying climate variability.