Phylogenetic Structure of a Rare Plant Community in Houhe Nature Reserve over Time and Space

The phylogenetic structure of a community is composed of all genetic relationships between species across the community. Understanding the phylogenetic structure of a community will help reveal the relative importance of habitat filteringꎬ competitive exclusion and the stochastic processes constructing the community. We studied a rare plant community in a 1 hm permanent plot in Houhe Nature Reserveꎬ Hubei Province. We examined the effects of spatial scales (5 m×5 mꎬ 10 m×10 mꎬ 20 m×20 mꎬ 30 m×30 mꎬ 40 m×40 mꎬ and 50 m× 50 m) and DBH classes (5 cm≤DBH<10 cmꎬ 10 cm≤DBH<15cmꎬ 15 cm≤DBH<20 cmꎬ and DBH≥20 cm) at spatial scales (10 m ×10 mꎬ 20 m×20 mꎬ 30 m ×30 mꎬ 40 m ×40 mꎬ and 50 m×50 m) on phylogenetic structure of the community in a subtropical evergreen and deciduous broadleaf mixed forest. The results demonstrated thatꎬ with increasing spatial scaleꎬ the phylogenetic structure tended to cluster. The degree of phylogenetic clustering decreased with increasing DBH classes. Howeverꎬ the degree of phylogenetic clustering was very high at the scale of DBH≥20 cm. The phylogenetic structures of the communities were random at the scale of 25 m and clustered at scales of 100 m and largerꎬ indicating that neutrality may play a leading role at small scales and niche processes may be more important at large scales for community assembly in subtropical evergreen and deciduous broadleaf mixed forest in this case.