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

The increasing frequency and intensity of drought events in temperate regions threaten forest ecosystem stability. However, the multidimensional stability, including resistance, recovery, and temporal invariability, and its ecological drivers, remain poorly understood. In this study, we integrate trait-based approaches with biomass dynamics reconstructed using tree rings from temperate forests in northeastern China to explore how functional composition and diversity influence multidimensional stability across varying drought regimes. Using 234 drought events, we quantified four dimensions of stability: resistance (capacity to withstand drought), recovery (ability to regain productivity after drought), resilience (return to pre-drought levels), and temporal invariability (long-term stability in productivity). We found significant linear and nonlinear relationships among stability dimensions, demonstrating their interdependencies. Communities dominated by conservative strategies, characterized by higher wood density, exhibited greater resistance and temporal invariability. By contrast, communities dominated by acquisitive strategies, characterized by larger specific leaf area, showed rapid recovery, though the benefits of these strategies decreased with increasing drought intensity. Functional diversity improved resistance during prolonged droughts but hindered recovery, highlighting context-dependent trait effects. This study emphasizes the importance of establishing a comprehensive stability framework that integrates drought characteristics and community traits to predict forest responses to climate extremes.