Abstract: Study on plant community condition and its succession of Maqu alpine desertified meadow is necessary for the environment ecological restoration and grassland productivity improvement.Plant populations of 20 sampling plots were investigated through quadrat sampling method by monitoring the characteristics of important value,niche breadth,and niche overlap of main species.The results show that the dominant species was Stipa aliena.in Maqu alpine desertified meadow.The greatest niche breadth was found for species of Thalictrum alpinum and Euphorbia esula and valued 0.974,while the dominant specie S.aliena only 0.941.This indicated the dominant species was not the strongest and most competitive population and the status of communities could be instable.The populations of T.alpinum and E.esula also had the largest niche overlap value at 0.987 indicating their strong competition potential in the community.Therefore,the succession direction of experimental zone would be replacement of the dominant species by miscellaneous grasses and further degradation of the alpine desertified meadow could be developed without timely restoration.

Key words: Alpine desertified meadow, Important value, Niche breadth, Niche overlap

摘要： 研究高寒沙化草地植物群落特征和演替状况,对恢复生态环境、提高草地生产力具有重要意义。本文采用样方法对玛曲高寒沙化草地20个样地的植物种群进行系统调查,并计算其主要植物的重要值、生态位宽度和生态位重叠值。结果表明:该草地当前的优势种为异针茅(Stipa aliena);生态位宽度最大的是亚优势种高山唐松草(Thalictrum alpinum)和乳浆大戟(Euphorbia esula),为0.974,而优势种异针茅仅0.941,说明优势种并不具有最强适应能力和竞争力,在群落中的地位也不稳定;生态位宽度大的物种之间具有大的生态位重叠值,其中高山唐松草和乳浆大戟生态位重叠值最大,达0.987,与其他种群之间的竞争也较强,表明高寒沙化草地的演替方向将是杂类草取代禾草的优势地位,如不及时治理,草地将进一步退化。

关键词: 高寒沙化草地, 重要值, 生态位宽度, 生态位重叠值