短尾杜鹃群落结构及多样性研究

Study on Community Structure and Diversity of Rhododendron brevicaudatum

短尾杜鹃是贵州特有珍稀濒危植物,为了探究其群落结构和多样性,采用样方法调查分析了2个短尾杜鹃群落物种组成、区系特征、生活型谱、群落结构和多样性。结果表明,群落Ⅰ有维管束植物39科59属72种,群落Ⅱ有维管束植物45科71属95种。属的分布区类型以热带成分为主,群落Ⅰ和群落Ⅱ热带性质的属分别占总属数的50.00%,41.27%;生活型谱以高位芽植物占优势,群落Ⅰ和群落Ⅱ分别占总数的66.67%,70.53%;2个群落分层明显,垂直结构可分为乔木层、灌木层和草本层。2个群落径级结构(DBH≥1 cm)和高度级结构呈"倒J型"或"单峰型",更新良好,主要优势种种群为增长型或稳定型;2个群落属和种的相似性系数分别为0.3684、0.2014,多样性指数在不同群落和同一群落不同层次间存在差异。群落Ⅱ的Margalef指数、Simpson指数、Shannon-Wiener指数和Pielou指数高于群落Ⅰ;灌木层狭叶方竹占绝对优势,分布不均匀,各多样性指数最低(群落ⅡMargalef指数除外)。群落Ⅰ人为活动较少,演替时间更长,处于演替后期阶段,向顶级群落发展,群落Ⅱ受人为干扰频繁,处于演替中期阶段。

The Rhododendron brevicaudatum is a rare and endangered plant peculiar to Guizhou.To explore the community structure and diversity,the species composition,faunal characteristics,life form spectrum,community structure and diversity of two R.brevicaudatum communities were investigated and analyzed by sample method.The results showed that there were 72 species of vascular plants belonging to 59 genus and 39 families in communityⅠ,while there were 95 species belonging to 71 genus and 45 families in communityⅡ.The distribution types of genus were mainly tropical type,and the genus in communityⅠand communityⅡaccounted for 50.00%and 41.27%of the total genera,respectively.The life form spectrum was dominated phanerophyte,and the communityⅠand communityⅡaccounted for 66.67%and 70.53%of the total respectively.The vertical structure of the two communities could be divided into tree layer,shrub layer and herb layer.The diameter structure(DBH≥1 cm)and the height structure of the two communities were"inverted J-shaped"or"single peak type",with good regeneration,and the dominant species population was either growing or stable.The similarity coefficients of genus and species in the two communities were 0.3684 and 0.2014 respectively,and there were differences in diversity index among different communities and at different levels in the same community.The Margalef index,Simpson index,Shannon-Wiener index and Pielou index in communityⅡwere higher than those in communityⅠ.The Chimonobambusa angustifolia was dominant within shrub layer with inhomogeneous distribution and the diversity index was the lowest(except for Margalef index of communityⅡ).The communityⅠhad less human activity and longer succession time,and it was in the late stage of succession and developed towards the apex community.In addition,the communityⅡwas in the middle stage of succession due to frequent human disturbance.