不同放牧强度下高寒灌丛群落特征和演替规律的数量研究

本文应用多样性指数、聚类分析等数学方法，研究了不同放牧强度下高寒灌丛群落特征的变化，用主分量分析方法，研究了不同放牧强度下高寒灌丛的演替规律。多样性分析结果表明，植物多样性指数在放牧强度为C组的草场达到最大。聚类分析结果，当相关系数R≥0.90 时，以重要值为特征的植物聚合为10类，它们分别属于植物群落不同演替阶段的建群种、优势种和伴生种。主分量分析表明，5个不同放牧强度的高寒灌丛群落聚合为3类，A和B组草场属于以灌木和杂类草为优势植物的2层结构的植物群落，C组草场属于以灌木为建群植物、杂类草和耐牧的莎草为共优势植物的2层结构的植物群落，D和E组草场属于以灌木为建群植物、禾草和莎草为共优势植物的3层结构的植物群落。

A QUANTITATIVE STUDY ON CHARACTERISTICS AND SUCCESSION PATTERN OF ALPINE SHRUB LANDS UNDER DIFFERENT GRAZING INTENSITIES

The characteristics and sucession pattern of alpine shrub lands under different grazing intensities are studied with methods of diversity analysis, clustering and principal component analysis in this paper.The results of diversity analysis show that plant diversity reaches the maximum in the C-group of pasture. The clustering analysis results show that when the correlation coefficient R≥0.90, the plant species taking importance value as characteristic are grouped into 10 types, belonging to constructive plants, dominant plants, and associated plants of different successive phases of plant communities respectively. Principal component analysis has shown that 5 communities of alpine shrub lands under different grazing intensities are grouped into 3 types. The A and B groups of pastures belong to plant communities of 2-layer structures taking shrub and forbes as dominant plants and, the C group of pastures belongs to plant communities taking shrubs as constructive plants and taking forbes and grazing-resistant sedges as polydominant plants and, D and E groups of pastures belong to plant communities of 3-layer structures taking shrubs as polydominant plants.