旱泉沟流域次生植被不同恢复阶段的多样性特征

The diversity characteristics on secondary vegetation of different restoration stages in Hanquangou valley of Tianzhu county

采用TWINSPAN和DCA对旱泉沟流域次生植物群落进行了数量分类和排序,将植物群系划分为不同的群落类型,显示出植被群落的分布格局。在此基础上,应用物种丰富度、Simpson优势度指数、Shannon-Wiener多样性指数和Pielou均匀度指数分别研究不同植被群落类型物种多样性。通过各种指数对比,得出以下结论:①植被被划分为7个群落类型,代表了植被恢复的不同阶段;②对于特定的研究区域茶树沟,制约植被群落类型、植物种分布格局的主要因素是水分和热量;③从阶段Ⅰ到阶段Ⅶ,Simpson优势度指数,乔木、灌木、草本基本持平,Shannon-Wiener多样性指数为乔木<灌木<草本,Pielou均匀度指数,乔木>草本>灌木,物种丰富度逐渐升高。群落的物种组成和空间结构逐渐复杂化,并趋于稳定。

The two-way indicator species analysis and the detrended correspondence analysis are adopted to classify and rank the quadrats of the secondary plant in the Hanquangou valley in Gansu province.The flora can be divided into different community types,and demonstrate the distributed pattern of the vegetation community in this region.Based on this result,the species richness index,the Simpson dominance index,the Shannon-Wiener diversity index and the Pielou evenness index are used to study the species diversity of different vegetation community types.The results shows that there are 7 community types,which represents the different restoration stages.The primary limiting factors are water and heat in specific region,Chashugou valley.From restora-tion stage Ⅰt oⅦ,as for the Simpson dominance index,tree layer,shrub layer and herb layer are approximately equal,the Shan-non-Wiener diversity index manifests as tree layer〈 shrub layer 〈herb layer,the Pielou evenness index manifests as tree layer〉 herb layer 〉shrub layer,and the species richness increase gradually.The species composition and the spatial structure of the community become complication gradually,and tend to be stable.