Abstract:

Studying species coexistence and successional dynamics of varying stand ages is important to understanding the mechanisms of community assembly. In this study, we divided a 20 ha subtropical forest plot in southern China into two groups, mature and old (over-mature), according to tree size and historical records. Species compositions, floristic characteristics and tree size distribution between the groups were compared. Results showed that species composition of the two groups were similar with comparable diversity indices but different species richness, individual densities, total basal area and importance value (IV) of species. As for the floristic composition, there were about 90% genera of tropical species in both groups, but the genera had a higher proportion in the old than in the mature forest. Both groups had “J” shaped tree size distributions but the mature forest had higher IV in the middle size class while the old forest was highest in large size class. In conclusion, both the mature and old forests were in climax stages but had different community structures, which suggests that there were different assembly processes during development stages in the subtropical forest community.

Key words: Dinghushan plot, species composition, community structure, community assembly, forest gap