Abstract: The formation of species diversity patterns depends on the process of community assembly and species composition of community. The contribution of species with different abundance levels to community species diversity is highly controversial. In this study， species were ranked according to their abundance levels， resulting in two sequences-one from rare to common species and the other from common to rare species. Species were then sequentially added， and the changes in species diversity were analyzed. Niche breadth and niche overlap values were calculated using the Levins method， with the aim of elucidating the contributions of rare and common species to the species diversity of alpine meadow plant communities. Our results showed that： （1） The species abundance of alpine meadow showed a logarithmic pattern， and the frequency showed a “U” distribution pattern. （2） Common species played a dominant influence on the changes in α diversity. In the two sequences， the contribution rate of common species to α diversity ranges from 20.40% to 59.20%， while that of rare species was less than 2.80%. Meanwhile， rare species were the primary contributors to β diversity. The contribution rate of rare species to β diversity was higher than 40.69%， and that of the contribution rate of common species was between 1.06% to 5.40%. This dominant effect of both rare and common species results from species accumulation， with little difference in contributions from individual species. （3） The niche breadth and niche overlap of common species were higher than those of rare species. This finding emphasizes the importance of considering the ecological roles and contributions of different species to ensure the integrity and diversity of conservation， especially when considering different levels of species diversity.

Key words: α diversity, β diversity, Species abundance, Rare species, Common species, Niche

摘要： 物种多样性格局的形成依赖于群落构建过程和物种组成。其中，不同多度等级物种对物种多样性的贡献颇具争议。本研究根据多度等级将物种排序，形成稀有-常见种和常见-稀有种两条序列，逐一添加物种并分析物种多样性变化，采用“Levins”方法计算生态位宽度和重叠值，旨在分析稀有种和常见种对高寒草甸植物群落物种多样性的贡献。结果表明：（1）物种多度呈对数分布，频度呈“U”型分布。（2）常见种在两条序列中对α多样性贡献率为20.40%~59.20%，稀有种贡献率低于2.80%；稀有种对β多样性贡献率高于40.69%，常见种贡献率为1.06%~5.40%；这种主导效应是物种累积的结果，单个物种贡献差异不大。（3）常见种的生态位宽度和重叠值较稀有种大。研究结果强调在物种多样性保护中，特别是考虑物种多样性的不同水平时，需要综合考虑不同物种的生态角色和贡献，以确保生态保护的完整性和多样性。

关键词: α多样性, β多样性, 物种多度, 稀有种, 常见种, 生态位