Abstract: This paper studied the plant diversity along grazing disturbance gradient of five of main grassland communities in the Songnen Plain of China. The results showed that the grazing disturbed pastureland environment through livestock’s gnawing and treading and changed plant species composition and population’s dominance, causing the changes of p1ant diversity. The species richness of different communities were gradually lowered with the aggravating of grazmg intensity. The peaks of diversity indices were on the moderate or heavy grazing stages and were related ’to the species evenness increases of the different communities. The intermediate disturbance hypothesis referred to the different grazint stages in the different grassland communities, and this was closely related to soil environment factors. The results of β diversity measurement showed that the plant diversity of leymus chinensis community and L. chineasis community, But S. baicalensis-herb community and S.baicalensis -Filtheium sibiricum community manifested higher stability.

Key words: Grassland community, Grazing disturbance, α diversity, β diversity, Stability

摘要： 松嫩草原五个主要群落类型放牧干扰梯度对植物多样性影响的研究结果表明,在放牧过程通过牲畜的哨食、践踏作用干扰草原环境,使群落物种组成发生变化,优势地位发生更替,导致植物多样性变化。随着放牧干扰强度的增大,群落丰富度随之下降。多样性指数在中牧或重牧阶段出现峰值,主要缘于群落均匀度的增加。β多样性研究结果表明,羊草群落和羊草—杂类草群落植物多样性的耐牧性较差,而贝加尔针茅—羊草群落、贝加尔针茅—杂类草群落和贝加尔外茅—线叶菊群落,物种组成表现出较高的稳定性。

关键词: 草原群落, 放牧干扰, α多样性, β多样性, 稳定性