不同尺度下长白山次生杨桦林群落系统发育结构研究

本文研究了长白山5.2 hm2次生杨桦林样地的群落构建机制。以样地内47种胸径≥1 cm的木本植物为研究对象,构建了物种间的系统发育树,并分析了不同空间尺度和不同径级结构下群落的系统发育结构。结果显示,随着空间尺度的增大,群落系统发育结构的发散程度先增大后减小;而随着径级的增加,群落的系统发育结构呈现向发散变化的趋势。这表明竞争排除作用和非生物的筛选作用共同影响群落构建的结果。其中,在较小的尺度上竞争排除作用是决定群落构建的主要因素;而在较大尺度上则是非生物的过滤作用起主要作用。通过对群落系统发育β多样性与空间因子、环境因子进行方差分解,发现环境因子对系统发育β多样性的解释力较强。其中,土壤水分和土壤深度起最重要的作用。 

Multi-scale analysis on community phylogenetic structure of secondary Populus davidiana-Betula platyphylla forest in Changbai Mountains,northeastern China

This study aims to test the phylogenetic structure of a secondary Populus davidiana-Betula platyphylla forest ( PBF) for multiple-spatial scale and ranked diameter class in Changbai Mountains of northeastern China, for the purpose of understanding the underlying mechanism of forest community assembly. We built a phylogeny tree based on 47 wooding species whose DBH≥1 cm. The results showed that with the increase of spatial scale, the dispersion degree of phylogenetic structure first increase then decrease; and with the increase of diameter class, the phylogenetic structure changed to overdispersion trend. These results suggested that the community was influenced by the effects of competitive exclusion and the abiotic filtering. Specifically, in small spatial scale, the phylogenetic structure is mainly decided by the effects of competitive exclusion; while in large spatial scale, the phylogenetic structure is mainly decided by the effects of abiotic filtering. By decomposing phylo-beta diversity with spatial factors and environmental factors, we find that environmental factors are powerful in explaining phylo-beta diversity. Among which, soil moisture and soil depth are the key factors to interpret phylo-beta diversity variance.