Abstract: [Objective] Bayinbuluke alpine grassland was taken the research object to research the degradation succession of vegetation diversity in the hope of providing a theoretical basis for the scientific management of alpine grassland.[Method]By using the method of space to replace the time degradation gradient degradation successional sequence, the field investigation of plant communities during different alpine grassland degradation stages in Bayinbuluk was carried out.The variation of vegetation diversity was studied by using the index of α and β diversity.[Result]The results showed that Simpson index increased significantly by 9.6;-13.7; compared with non-degradation;and with the increasing degraded succession, Margalef index showed a slight increase and a significant decline trend, but the Shannon-Wiener index and Pielou index showed the fluctuation of upward then downward and upward change.In addition, with the worsening of grassland, the resource heterogeneity was decreased in the quadrat, but increased among quadrats, so the β diversity was increased.Cody index showed the tendency of "up-down", this result showed the species substitution rate increased first and then decreased.Bray-Curtis index was higher in light-degradation, mid-degradation and heavy-degradation grassland than non-degradation grassland, and it indicated that there were more common species among different degraded grasslands.[Conclusion]In the alpine grassland, species composition changed at different degradation succession stages, the forage grass with good palatability reduced, poisonous grass increased, resulting in reduction of the quality of grassland.

摘要： [目的]以新疆巴音布鲁克高寒草原为对象,研究植被多样性的退化演替规律,为高寒草原的科学管理提供理论依据.[方法]采用空间退化梯度代替时间退化演替序列的方法,对巴音布鲁克不同退化阶段高寒草原植物群落进行野外调查,运用α多样性、β多样性等指标研究植被多样性变化并探讨其演替规律.[结果](1)Simpson优势度指数在草地退化后显著上升了9.6;~13.7;,Margalef丰富度指数随着退化演替的加剧基本呈先略微增加后显著下降的变化趋势,而Shannon-Wiener多样性指数与Pielou均匀度指数均呈先增后降再增的波动变化;(2)随退化程度的加剧,样方内微生境或资源异质性减小,样方间异质性增大,从而导致β多样性增加;Cody指数(二元属性数据)先升高后减小,沿着退化梯度,物种替代速率加快后逐渐减慢;轻度退化与中度退化、重度退化间Bray-Curtis指数较大,说明退化梯度之间存在较多的共有种.[结论]高寒草原在退化演替过程中群落物种组成发生替代变化,适口性好的物种减少,毒害草增加,导致草地质量下降.