Studies on Species Diversity of Alsophila spinulosa Community in the Bijia Mountain of Yongding, Fujian

This paper analysed the species richness, species diversity index and community evenness in different plots and layers of Alsophila spinulosa community in the Bijia Mountain of Yongding, Fujian Province. The results show that the species diversity indexes of Alsophila spinulosa are biggest in the five layers of community vertical structure, except species richness. The species richness and diversity index of herb layer are the second, and the community evenness is the third. The species richness of shrub layer is the first, and the community evenness is the smallest. The species diversity indexes of the first sub-layer of tree layer, except the community evenness is the second, are the smallest. The diversity indexes of vine are the third or the fourth. The diversity indexes of tree layer or shrub layer or herb layer among various plots are somewhat different. Relatively, the differences of tree layer or shrub layer are small while differences of the herb layer and vine are comparatively big. The result also shows that the values of the Simpson's index and the interspecific encounter probability are almost equal in Alsophila spinulosa community.