漓江流域岩溶区檵木群落不同恢复阶段物种组成及多样性变化

Changes of species composition and diversity among restoration stages of Loropetalum chinense communities in karst area of Lijiang River valley

以空间代替时间的方法选取典型样地,采用常规群落学调查方法对漓江流域岩溶区立地条件基本一致的檵木(Loropetalum chinense)群落不同恢复阶段的植物物种组成及其多样性变化进行研究。结果表明,(1)在所调查的样方中,共记录维管束植物78种,隶属于45科70属。乔木层的建群种檵木随着群落的恢复其重要值有降低的趋势,而在灌木层则相反。檵木群落不同恢复阶段乔木层和灌木层主要优势种为檵木、小巴豆(Croton xiaopadou)、龙须藤(Bauhinia championii)、红背山麻杆(Alchornea trewioides)和紫凌木(Decaspermum esquirolii),草本层主要优势种为狭穗薹草(Carex ischnostachya)、庐山香科科(Teucrium pernyi)和蔓生莠竹(Microstegium fasciculatum)。(2)随着檵木群落的恢复,群落总体、乔木层和灌木层物种丰富度呈现增大的趋势,草本层则相反;Shannon指数和均匀度指数具有一致的变化趋势,乔木层Shannon指数和均匀度指数随檵木群落的恢复呈现增大的趋势,而灌木层、草本层和群落总体则相反。檵木群落不同恢复阶段灌木层Shannon指数均高于乔木层和草本层,而草本层均匀度指数均高于乔木层和灌木层;Simpson指数随檵木群落恢复的变化趋势与Shannon指数和均匀度指数相反。(3)在檵木群落的灌木阶段、乔灌阶段和乔林阶段这3个恢复阶段中,乔灌阶段与乔林阶段之间的乔木层、灌木层、草本层和群落总体的Bray-Curtis指数最大。

By adopting the concept of space as a substitute for time, we analyzed the changes of plant species composition and diversity of different restoration stages of Loropetalum chinense communities distributing in the karst area in Lijiang River valley. The results showed that, （1） we recorded 78 species of vascular plants from 45 families and 70 genera. The important value of Loropetalum chinense as the role of constructive species had a decreased trend in arborous layer, and the reverse trend in shrub layer. The main dominant species of arborous layer and shrub layer in different restoration stages of Loropetalum chinense communities were Loropetalum chinense, Croton xiaopadou, Bauhinia championii, Alchornea trewioides, Decaspermum esquirolii, and the main dominant species of herb layer were Cyperus compressus, Teucrium pernyi, Microstegium vimineum. （2） Species richness had an increased trend with community, arborous layer and shrub layer during Loropetalum chinense communities restoration, and the reverse trend in herb layer. Shannon index and evenness index had the accordant trend. Shannon index and evenness index of arborous layer had an increased trend with Loropetalum chinense communities restoration, a reverse trend accurred in the shrub layer, herb layer and community. The value of Shannon index in shrub layer was higher than in arborous layer and herb layer of the three different restoration stages, and the value of evenness index of herb layer was higher than arborous layer and shrub layer. The change of Simpson index with Loropetalum chinense communities restoration had the reverse trend to the Shannon index or evenness index. （3） Of the three restoration stage of Loropetalum chinense communities, the value of the Bray-Curtis index of arborous layer, shrub layer, herb layer and community between shrub to tree stage and tree stage were the maximum.