Abstract: In order to explore the dynamic characteristics of the stability and species diversity of different degraded meadow steppe,the community structure and plant diversity were analyzed. The results indicated that:the plants in the study area were mainly gramineae,compositae,rosaceae,sedge,leguminous and labiatae. With the increase of the degraded degree of grassland:the coverage of grassland decreases;the dominant species of the community changed from high quality herbage such as gramineae,sedge and leguminous to miscellaneous grass plants gradually;the dominance of perennial plants decreased,while dominance of annual weeds increased,the community stability became worse. The species richness of the non-degraded grassland was the largest,the moderately degraded grassland showed higher diversity,dominance,evenness and richness indexes than the non-degraded grassland,while the diversity indexes of other degraded grasslands had no significant difference. The plant communities of samples in non-degraded grassland were similar to each other,and the composition of plant communities was different from that of lightly,moderately and heavily degraded grassland. The plant community composition of lightly,moderately and heavily degraded grasslands were similar. The results provides reference for the restoration and reconstruction of degraded meadow steppe.

Key words: Meadow, Degradation, Plant diversity, Community

摘要： 为深入研究不同退化程度草甸草原植物群落多样性及稳定性的动态变化规律，本研究采用样方法对东乌珠穆沁不同退化程度草甸草原植物群落结构及多样性进行了调查分析。结果表明：研究区植物主要为禾本科、菊科、蔷薇科、莎草科、豆科、唇形科。随草地退化程度加剧：草地植被盖度减小；群落优势种从禾本科、莎草科、豆科等优质牧草逐渐转变为杂类草植物；多年生植物优势度下降，一年生杂草优势度上升，群落稳定性变差。未退化草地物种丰富度最大，中度退化草地较未退化草地表现出较高的多样性、优势度、均匀度、丰富度指数，其余草地类型多样性差异不显著。未退化草地样点间植物群落相似度较高，与轻度、中度、重度退化草地植物群落组成差别较大。轻度、中度、重度退化草地间植物群落组成存在相似性。本研究结果为退化草甸草原的恢复重建提供参考。

关键词: 草甸草原, 退化程度, 植物群落结构, 多样性