中文摘要：

通过丰富度指数、物种多样性指数和均匀度指数，结合TWINSPAN、DCCA排序及相关分析，研究了物种多样性及其变化机制，把植物群落分为8个群落类型；物种多样性指数变化的总体趋势是随着海拔的降低（从群落l到群落Ⅷ）而降低（Simpson指数除外），对于某一个群落，这些指数都反映出基本一致的趋势；物种多样性指数的DCCA第一轴基本上反映了海拔变化引起的土壤水分的变化，第二轴基本上反映了人类对群落的干扰程度，物种多样性指数随土壤水分的增加而增大，随人类干扰程度的增加而减小，环境因子中，氮、有机质、海拔与第一轴呈负相关，其余因子与第一轴呈正相关，而铜、pH值与第一轴夹角很小，说明它们和水分梯度有显著的正相关，而锰、电导率与第二轴夹角小，说明它们与第二轴相关性大，而磷和第二轴却呈显著负相关．图3表1参12

英文摘要：

By using richness, diversity and evenness indices, and combining with TWINSPAN, DCCA and correlation analysis techniques, plant species diversity and diversification mechanism were studied. The plant communities were classified into eight types by TWINSPAN. The species diversity indices were generally reduced with the lowering of （from community Ⅰ to community Ⅷ ） altitude （except Simpson index）. However, to certain communities, the indices reflected the basically unanimous trend. The first axis of DCCA basically indicated the diversification of soil water, while the second axis indicated the disturbance degree by people, so the species diversity indices were increased with soil water and reduced with the disturbance degree by people. The correlations among N, organic matter, elevation and the first axis were negative association, and the others were positive. The angle among Cu, pH and the first axis was very small, showing significantly positive association. The angle among Mn, electrical conductivity and the second axis was also small, showing significant association, and the correlations between P and the second axis were significantly negative. Fig 3, Tab 1, Ref 12