| The integration of evolutional biology and ecology is a new direction of ecological research, and this cross-discipline subject focuses on the study of the phylogenetic community structure and the processes that influence the communties assembly. Similarity limiting and habitat filtering are two main ecological processes that may infiuence the assembly of communities. And the role that these processes play in community structuring is a hot spot in both community ecology and evolutional ecology. The combination of different processes and traits evolution can produce different phylogenetic structures, including phylogenetic clustering, phylogenetic overdispersing and phylogenetic random dispersing. So, research on phylogenetic structure of communities can help us look insight of the biodiversity, community structure and assembly processes in a different, way.Habitat fragmentation is a hot spot in the study of ecology and conservation biology. The fragmentation effects (including habitat loss, isolation effect, edge effect, matrix effect) not only influence the community structure and species diversity, and also influence the phylogenetic diversity and structure. Nevertheless, there was not much research about the effect of habitat fragmentation on community phylogenetic structure yet, and studies focused on small-scale of time and space are even fewer. So combine habitat fragmentation and phylogenetic structure together can illuminate new concepts in the researching of the effect of habitat fragmentation on biodiversity.This research used the bird communities of42islands on the Thousand-island Lake with different area, shape and isolation as target. And the data was selected from the bird surveys during2007.4and2011.1. By building up the phylogenetic tree of87species, using multiple phylogenetic metrics (Faith’s Index, MPD, MNTD, NRI, NT1) and null model to analyses the bird communities phylogenetic pattern, the effect of fragmentation on it and the ecological process that mainly influence the assembly.There were seasonal differences in phlogenetic diversity. The phylogenetic diversity of spring communities were higher than winter. Because the phyiogenetic tree included some polytomouss branches. the difference of species richness between spring and winter may be the main factor that leads to the difference of phylogenetic diversity. There were also seasonal differences in phylogenetic structure. The bird communities in winter were more phylogenetic dispersed. The winter species covered almost all the families and genera in the phylogenetic tree and this may be the explanation.There was no significant phylogenetic structure of the bird communities. No matter spring or winter, most communities’structure showed no phylogenetic clustedness or dispersedness. This inferred that similarity limiting and habitat filtering may not be the main processes that influence the community assembly. But we found a habitat selection happened when the birds dispersed between islands, so the island habitats did affact the community assembly in a way. The community assembly on big islands was partially influenced by habitat filtering. And the community assembly on small islands was more randomly, and affected by the randomly disperse.There was some area effect in the influence of habitat fragmentation to the community phtlogenetic partterns. The area and shape of the island affected the phylogenetic diversity and structure of bird communities on big islands. The increasing of area and edge can raise the community phylogenetic diversity. But the phylogenetic clustedness also inceased when the area became larger, and decreased when there was more edge. Isolation didn’t affect the phylogenetic pattern on big islands. While for small islands, area and shape didn’t influence the phylogenetic pattern significantly. Isolation had a negative effect on phylogenetic diversity. The increasing of isolation increased the phylogenetic clustedness, and the community composition became more simple. |
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