Abstract: In order to understand the community types of low-altitudinal tropical forests in Bawangling of Hainan Island, a field investigation was conducted at 21 sampling plots, and the quantitative classification and ordination on the community types were made by using two-way indicator species analysis (TWINSPAN), principal components analysis (PCA), and detrended correspondence analysis (DCA). Based on TWINSPAN, the forest communities in Bawangling were classified into 3 types, i.e., tropical lowland rainforest (plots 9-12), transformed monsoon rainforest (plots 1-8), and tropical monsoon rainforest (plots 13-21). Same results were obtained by PCA and DCA ordination, which basically reflected the relationships between forest communities and environmental factors. Tropical lowland rainforest was positively correlated with altitude and litter depth, tropical monsoon rainforest was positively correlated with slope and the coverage of exposed rock surface, while transformed monsoon rainforest had somewhat different correlations with environmental factors. The results of DCA ordination also indicated that transformed monsoon rainforest was a transitional community type between tropical lowland rainforest and tropical monsoon rainforest.

Key words: Hydrological scale, Scaling