Abstract:

Aims: This study aims to reveal the temporal dynamics and driving mechanisms of species composition in temperate forest seedling communities, which is crucial for understanding forest regeneration and guiding sustainable forest management. 

Methods: Based on continuous monitoring data from 1 m × 1 m seedling plots within a 20 ha forest dynamic plot at Donglingshan, Beijing, between 2021 and 2024, we employed the temporal beta diversity index (TBI) and its decomposition into loss and gain components to analyze temporal changes in seedling community composition. Relationships between TBI and seedling growth indicators, stand structure, soil, and topographic factors were assessed to identify the primary drivers of temporal dynamics. 

Results: The results showed a gradual increasing trend in TBI over the study period. Species losses exceeded gains from 2022 and 2023, whereas gains predominated from 2021 to 2022 and from 2023 to 2024. TBI was significantly negatively correlated with mean seedling height and positively correlated with total seedling cover and tree abundance. No significant correlations were found with soil or topographic factors. 

Conclusion: This study demonstrates that the temporal dynamics of the seedling community showed distinct stage-specific patterns: changes from 2022 to 2023 were mainly driven by stand structure–mediated environmental constraints, resulting in community simplification characterized predominantly by species loss; whereas the period from 2023 to 2024 transitioned into a resource–release phase, promoting species gains. These dynamics were primarily regulated by seedling growth traits. Future long-term monitoring will help to better elucidate the dynamics of seedling regeneration processes. The findings provide a theoretical foundation for the management and sustainable restoration of temperate secondary forests.

Key words: temporal beta diversity, species composition change, seedling regeneration, stand structure, forest management