中文摘要：

应用双向指示种分析法（TWINSPAN）和除趋势对应分析（DCA）等数量分析方法，对山西云顶山亚高山草甸生态关系进行了研究，将该草甸划分为5个群落类型，分别位于不同的海拔高度。分类结果很好地反映了植物群落类型及优势种的分布与环境因子之间的关系，并在DCA二维排序图上得到了较好的验证。DCA排序轴反映了海拔高度、放牧强度和群落土壤湿度的梯度变化，表明海拔高度和水热条件是影响植物群落变化的主要环境因子，物种多样性在群落类型分化中有重要作用，同时放牧对亚高山草甸演替过程的干扰明显。

英文摘要：

Based on the field investigation of community plots, two-way indicator species analysis （TWlNSPAN） and detrended correspondence analysis （DCA） were applied to analyse the ecological relationships on subalpine meadow communities in Yunding Mountain, Shanxi province. It was showed that： （1）five meadow communities of 36 samples located in different altitudes were recognized by TWlNSPAN and characteristics of the communities were described respectively, including distribution of dominant species and relationship with environmental factors. All results were confirmed by the two-dimensional ordination diagram of DCA. （2）The environmental variables, such as altitude, grazing intensity, moisture and heating conditions, were the major environmental factors affecting community＇s change. The results of DCA ordination showed that the five meadow communities had their different distributions along their environmental gradient. The first axis and the second axis of DCA reflect the gradient of elevation, grazing intensity and soil water conditions of the communities. （3） The distribution patterns of dominant species were highly similar to that of the communities. With the increase of the altitude, Kobresia bellardii, Carex lanceolata , Festuca ovina and Taraxacurn rnongolicurn gradually took the dominant status on the communities, which showed that community distribution patterns were coordinate to the zonal vegetation distribution patterns due to the increase of elevation and the decrease of human interruption. （4）The difference in species diversity of the community had close correlation mainly to the specific evenness and grazing intensity, meanwhile, also had close correlation to the meadow habitat. Species diversity of the meadow distributing in the semi-sunny slope, semi-shady slope, shady slope and high altitude area, due to its better water supply and temperature environment, was much richer than that on the sunny slope and low altitude area. Also habitat conditions degraded because of intensi