Effects of environmental filtering and dispersal limitation on species and phylogenetic beta diversity in Gutianshan National Nature Reserve

Abstract

Phylobetadiversity can provide new insights into assembly mechanisms of community ecology because it incorporates phylogenetic information. The combination of phylobetadiversity and traditional species beta diversity is of great benefit to research that attempts to explain the mechanisms of community assemblages. To reveal the community assembly mechanisms of a 24-hm2 forest plot established in Gutianshan National Nature Reserve, Kaihua County, Zhejiang, China, our study used four spatial statistical models to simulate model communities created in four ways: purely random processes, environmental filtering, dispersal limitations and the combination of environmental filtering and dispersal limitation. Then we analyzed the distance-decay of similarity of these four model communities and observed communities based on the plot in the Gutianshan National Nature Reserve. Our results showed (1) an obvious distance-decay relationship exists for species and phylogenetic similarity in the Gutianshan plot; (2) the combined effects of environmental filtering and dispersal limitation can best explain the mechanisms involved in structuring species beta diversity in the plot; and (3) different results were produced using pairwise ( D pw) and nearest neighbor ( D nn) metrics. The results from the nearest neighbor metric ( D nn) suggested that the combined effects of environmental filtering and dispersal limitation shape the community phylogenetic structure of the plot. Additionally, the results from the pairwise metric ( D pw) showed that the combined effect of environmental filtering and dispersal limitation can best explain the community phylogenetic structure at the scales of 20 m2×20 m2, while environmental filtering is the main force shaping community phylogenetic structure at scales of 40 m2×40 m2 and 50 m2×50 m2. The combined patterns observed when considering both phylobetadiversity and traditional species beta diversity reflected the important roles of habitat filtering and dispersal limitation in diversity maintenance of this subtropical forest habitat.