Phylogenetic Development And Functional Structures During Successional Stages Of Conifer And Broad-leaved Mixed Forest Communities In Changbai Mountains,China

Community assembly has long been an important issue in community ecology.By quantifying the influence of habitat filtering,competitive exclusion,and random community assembly on the phylogenetic and functional traits,ecologists would gain a deeper understanding of community construction.In this study,based on the datasets of three 5.2-hm2 permanent plots at different successional stages(i.e.,a Populus davidiana.Betula platyphylla secondary forest,a secondary conifer and broad-leaved mixed forest,and a Tilia amurensis-Pinus koraiensisforest),we established the phylogenetic trees according to the Angiosperm Classification System(APG Ⅲ)and seven functional traits(i,e.,leaf area,specific leaf area,leaf thickness,leaf nitrogen content,leaf phosphorus content,nitrogen-phosphorus ratio,and maximum tree height).We correlated the phylogenetic trees with the environmental variables to examine the patterns of the phylogenetic and functional structures of the forest communities at different successional stages in Changbai Mountains of China.The results showed that:(1)at each successional stage,significant phylogenetic signals were found for all seven functional traits,indicating that the functional traits were influenced by the phylogenetic history.(2)The phylogenetic and functional structures changed from "clustered" to "overdispersed,during the succession of forest community.Meanwhile,the degree of phylogenetic and functional clustering decreased with an increase in diameter class,indicating a significant increase in competitive exclusion with the succession of forest community.(3)As with the spatial scales,The phylogenetic and functional structures changed from "clustered" to "overdispersed",indicating that environment filtering had a dominate role on community assembly in small scale,while dispersal limitation and competition exclusion had a dominate role on community assembly in large scale.(4)In the early succession stage,dispersal limitation and environment filtering were more important in community assembly;along with the succession stages,species composition and community structure gradually stabilized,competition exclusion dominated community assembly in Tilia amurensis-Pinus koraiensis mixed forest.