关键词: 群落结构, 谱系发散, 谱系聚集, 径级结构, 种子传播, 生境过滤

Abstract

Community phylogenetic structure contains information about evolutionary relationships among coexisting species in a community. Studies on community phylogenetic structure provide new insights into ecological processes and the mechanisms underlying community restoration. We compared the phylogenetic structure of forest communities along a human disturbance gradient using data from 12 1-ha plots in secondary forests within the Gutianshan National Nature Reserve, Zhejiang Province, China. We found that, at the 20 m×20 m scale, the plantation forest community (I) was phylogenetically overdispersed. Forest communities II (naturally-restored forest 50 years after clear cutting and 20 years after heavy selective cutting), III (naturally-restored forest 50 years after clear cutting), and IV (old-growth forest) were phylogenetically clustered. Forest types II and IV were the most clustered. We also conducted the same analyses for four forest types grouped into different DBH classes, and found that forests II, III, IV with DBH less than 5 cm and 5-10 cm were phylogenetically clustered, but forest I was overdispersed. In contrast, all the forests with DBH more than 10 cm were phylogenetically overdispersed except the forest IV. Our results suggest that seed dispersal is the main process resulting in phylogenetic overdispersion at early stage of succession, and habitat filtering is main process leading to phylogenetic clustering when habitat heterogeneity increases during succession. Possibly as a result of habitat filtering, forest IV was always phylogenetically clustered regardless of which size class was examined.

Key words: community composition, phylogenetically overdispersed, phylogenetically clustered, diameter classes, seed dispersal, habitat filter