AimsWe analyzed the differences in functional traits of different growth forms of woody plants in a tropical rainforest of Xishuangbanna, and revealed the changing rules and influencing factors of functional diversity of woody plants with different growth forms.

MethodsBased on the survey data and the functional traits of woody plants from three 1 hm² dynamic monitoring plots in Menglun, Bupung, and Shangyong in Xishuangbanna Nature Reserve, China, one-way variance analysis, principal component analysis, Pearson correlation analysis, redundancy analysis, and multiple linear regression analysis were used to analyze the changes and influencing factors of functional diversity among different growth forms of woody plants, and to discuss the functional characteristics and main influencing factors of woody plant communities in the tropical rainforest of Xishuangbanna.

Results(1) The community weighted mean value of leaf area, leaf carbon content and leaf dry matter content of trees were significantly higher than those of shrubs and lianas, while the community weighted mean value of leaf nitrogen content and specific leaf area of lianas were significantly higher than those of trees and shrubs. (2) The functional richness and functional dispersion of trees were higher than those of shrubs and lianas, while the functional evenness and functional divergence of shrubs were higher than those of trees and lianas. (3) The functional richness of trees and lianas and the functional dispersion of lianas increased significantly with increasing plant species richness, abundance and phylogenetic diversity. The functional evenness and functional divergence of trees increased significantly with increasing of soil fertility, while the functional dispersion of shrubs increased with increasing plant species richness. (4) Abundance was the main factor affecting the community weighted mean value of functional traits of trees and shrubs, while phylogenetic diversity, plant species richness and soil fertility were the main factors affecting the community weighted mean value of functional traits of lianas.

Conclusion This study reveals that functional traits and functional diversity have significant differences among different growth forms of woody plant communities in the tropical rainforest of Xishuangbanna. Moreover, woody plant abundance and soil fertility play a crucial role in maintaining the functional diversity of plant communities in a tropical rainforest in maintaining plant community functional diversity.