The Preliminary Studies On Species And Phylogenetic Beta Diversity Of Subtropical Forest Communities In Gutianshan, China

Species beta diversity can be used to describe the dissimilarity of species composition among communities, but it is uninformative about the dissimilarityof phylogenetic relationships among communities. Phylobetadiversity can provide new insights into assembly mechanisms of community ecology due to its incorporation of phylogenetic information. The combination of phylobetadiversity and traditional species beta diversity is of great benefit to research of the mechanism of community assembly.In order to reveal the community assembly mechanisms of Gutianshan forest plot, our study used four spatial statistical models to simulate model communities determined by pure random process, environmental filtering, dispersal limitation and their combination. Then we analyzed the distance-decay of similarity of four model communities and observed communities based on the24-ha plot in the Gutianshan National Nature Reserve. These four model we used were as follows:Homogenous Poisson model in which the species distribution in communities is dominated by random process; Heterogeneous Poisson model in which the species distribution in communities is dominated by environmental filtering; Homogenous Thomas model in which the species distribution in communities is dominated by dispersal limitation; Heterogeneous Thomas model in which the species distribution in communities is dominated by environmental filtering and dispersal limitation.Our results showed that (1) There are obvious distance-decay relationship of species and phylogenetic similarity in Gutianshan plot.(2) The joint effect of environmental filtering and dispersal limitation can best explain mechanisms structuring species beta diversity in the plot.(3) There were different results by using pairwise (Dpw) and nearest neighbor (Dnn) metrics:The results from nearest neighbor metric (Dnn) suggested that the joint effect of environmental filtering and dispersal limitation shape the community phylogenetic structure of the plot. On the other hand, the results from pairwise metric (Dpw) showed that the joint effect of environmental filtering and dispersal limitation can best explain the community phylogenetic structure at the scales of20m×20m, whereas the environmental filtering is the main force shaping community phylogenetic structure at scales of40m×40m and50m×50m. The pattern from from phylobetadiversity and traditional species beta diversity collectively reflected the important roles of habitat filtering and dispersal limitation in diversity maintenance of subtropical forest.