Abstract: samples collected in Bothriochloa ischaemum formation of southeast Shanxi province were classified into 17 associations by Twoway Indicator Species Analysis(TWINSPAN). The diversity of species composition of B. ischaemum communities in southeast Shanxi province was examined. The characteristics of the plant species diversity of 17 associations of B. ischaemum communities were studied by use of the formulas of richness indices(R₁),Simpson’s indices(λ), ShannonWeiner’s indices (H′) and evenness indices(E₁). In addition, the relationships among these indices of 17 associations were analyzed by use of correlation analysis. The results indicated that: 1) There were 76 species classified into 60 genera and 28 families, of which, 78.95% and 69.74% of the total species wre herbaceous plants and of mesophyte. 2) The species diversity indices of 17 associations varied according to the site conditions and anthropogenic effects. The slowclinal changes of diversity indices indicate that 17 associations were adaptative to the local climatic conditions. 3) The order of the species diversity indices of the 17 associations showed that the species diversity of the shrubherbosa was significantly higher than that of the herbosa. 4) The indices of H′. λ and E₁ demonstrated higherconsistency, while H′ and λ can also reflect dominant species effect in the communities.

Key words: Bothriochloa ischaemum, Formation, Association, Species diversity, Shanxi

摘要： 采用双向指示种分析法,将山西东南部白羊草群系分为17个群丛。采用样方法统计分析其多样性,应用丰富度指数(R₁)、Simpson指数(λ)、Shannon-Weiner指数(H′)和均匀度指数(E₁)研究17个白羊草群丛的植物种多样性,对其多样性指数间的关系进行相关分析。结果表明,1)组成白羊草群系的维管植物有76种,隶属于28科60属,其中草本植物占总种数的78.95%。在生态构成上以中生性植物为主,占69.74%;2)群系植物种多样性指数的大小受立地生境和人为活动的综合影响。群系间植物种多样性指数的平缓变化表明17个群丛对地带性气候具有相似的适应性;3)依据群系植物种多样性指数的大小对17个群丛进行排序后发现:含有灌木的群丛比纯草群丛的植物种多样性指数明显偏高;4)用H′指数、λ指数和E₁指数描述群丛性质时存在较好的一致性,λ指数和H′指数可测度优势种在群丛中作用的大小。

关键词: 白羊草, 群系, 群丛, 多样性指数, 山西