Linking drought characteristics and community functional traits to explain multidimensional forest stability

1. Increasing frequency and intensity of drought events under global climate change pose critical threats to forest ecosystem stability. Yet, the multidimensional nature of stability including resistance, recovery and temporal invariability and its ecological drivers remain poorly understood, particularly in mature, structurally complex forests. 2. Here, we integrate trait-based approaches with tree-ring reconstructions across temperate forests in northeastern China to investigate how functional composition and functional diversity influence different dimensions of forest community stability under varying drought regimes. Using a dataset of 234 drought events from 2001 to 2022, we quantified community biomass dynamics and four stability metrics. 3. We found significant linear or nonlinear relationships among stability dimensions, highlighting the strong interdependencies between resistance, recovery, resilience, and temporal invariability. Functional composition, especially traits associated with conservative strategies (high wood density), enhanced resistance, resilience and long-term stability, while acquisitive traits (high specific leaf area) promoted more rapid recovery and resilience. However, the benefits of acquisitive traits diminished with increasing drought intensity. Functional diversity improved resistance during prolonged drought periods, but negatively affected recovery, indicating context-dependent effects of trait complementarity. 4. Our study confirms the important role of adopting a multidimensional framework that integrates drought characteristics with community functional traits provides a robust basis for predicting forest responses to climate extremes and guiding management strategies to sustain ecosystem functioning.