The Species Diversity and Patch Characteristics in Subtropical Evergreen and Deciduous Broad-Leaved Mixed Forest

Forest communities are composed of different developmental types (gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). The mean basal area, mean volume of each individual, mean DBH, standing volume, and mean height, all significantly increased along the process of forest cycle (G-B-M-D) (p<0.05). Different sized individuals and different functional groups only appeared in specific patch types. Bigger individuals mainly occurred in the late phase (M and D). Generalist species (GES) mainly existed in the G, while infrequent species (INF) and fern mainly appeared in the M. β diversity index of non-adjacent patch phases was higher than that of the two adjacent patch phases, and in the G, species richness and diversity were the highest among four different patches (G, B, M and D). A possible mechanism that could explain the diversity maintenance in subtropical evergreen and deciduous broad-leaved mixed forest was put forward.