Abstract:

How forest communities maintain their biodiversity has been challenged ecologists during the last few decades. Negative density-dependence and habitat filtering have been proposed as key players in community assembly. However, few studies have explored how negative density dependence and habitat filtering impact seedling dynamics over time. To test the relative roles of these two mechanisms in community assembly, we analyzed the temporal trends of functional α and β diversity in seedling communities in the 24 ha Gutianshan forest dynamics plot during 2006-2007. We found that functional α diversity within communities significantly increased over time except for functional α diversity associated with stomatal density. Functional β diversity significantly increased with time for five traits (such as wood density, specific leaf area, leaf nitrogen content, leaf phosphorus content and stomatal density) between communities. Our results suggest that negative density dependence can promote functional α diversity at local scales, while habitat filtering can partly explain functional β diversity.

Key words: subtropical evergreen broad-leaved forest, seedling, Gutianshan, functional alpha diversity, functional beta diversity, community assembly