The altitude pattern of woody plant diversity of Xingdoushan

The woody plant species richness,community diversity and spatial distribution features were analyzed based on sampling plots in Xingdoushan Nature Reserve,Hubei,China. The research also took Rapoport's altitude rule as a case study. Results showed that the forests in Xingdoushan consisted of multi-species dominant communities. The trees whose importance values were more than 15included Cunninghamia lanceolata,Phoebe zhennan,Tetracentron sinense,and Cyclobalanopsis glauca. The physiognomy of the community changed with elevations. The α diversity,presented by the Simpson and Shannon-Weiner indices,decreased for both the tree and shrub layers with increasing altitude. The β diversity,which was indicated by the Cody index,declined with increasing altitude.These patterns supported Rapoport's altitude rule. Furthermore,the species diversity was significantly different among aspects. The Simpson index was the highest in the east and northeast aspect,followed by west,and the lowest in north aspect. The species diversity of shrub layer was higher than the tree layer at same forest community due to environment differences in canopy layers.