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雅鲁藏布江流域作为西藏重要的人口聚居区,其植物群落结构及多样性格局吸引着众多学者的关注.本文沿雅鲁藏布江中上游流域河岸两侧原生生境设置44个样地,共计220个样方,计算植物的重要值并进行群落分类.结合1985–2015年多年平均降水量和多年平均气温数据以及样地的坡位、坡度等生境数据,采用偏冗余分析(偏RDA)的方法探讨雅鲁藏布江中上游地区植物多样性分布格局及其环境影响因素,根据样地的生物多样性指数预测雅鲁藏布江中上游地区植物多样性分布格局.结果表明:研究区植被群落按重要值划分为垫型蒿—紫花针茅群落、藏沙蒿—羊茅群落、金露梅—固沙草群落、三角草—冷蒿群落、高山嵩草群落、砂生槐—臭蒿群落、砂生槐—白草群落等7个群落;生物多样性随着经度降低、纬度升高和海拔增加而减少;雅鲁藏布江中上游植物多样性分布格局具有明显的地带性特征,水分和热量对植物多样性分布格局的解释率分别为19.3％和5.7％,而二者共同解释了60.8％的空间变异,耦合效应明显;雅鲁藏布江中上游地区植物多样性呈现由西北向东南逐渐升高的分布格局.“,”The Yarlung Zangbo River Basin is an important populated area in Tibet, and its plant community struc-ture and diversity pattern have attracted the attention of many scholars. In this paper, the distribution pattern of plant diversity and the environmental factors impacting it in the middle and upper reaches of the Yarlung Zangbo River are revealed and discussed through sample surveys and climate and habitat data. The results show that the plant communities in the study area can be divided into seven types according to the dominant species:Artemisia minor + Stipa purpurea,Artemisia welbyi + Festuca ovina,Potentilla fruticosa + Orinus thoroldii,Trikeraia hookeri+Artemisia frigida,Kobresia pygmaea,Sophora moorcrof tiana+Artemisia hedinii, andSophora moorcrof tiana +Pennisetum centrasiaticum. Plant diversity decreases with decreasing longitude, increasing latitude, and increasing altitude; and the diversity distribution pattern in the study area has distinct zonal characteristics. Water and heat are the main factors which affect the distribution of vegetation types. The explanation rates of water and heat for the plant diversity distribution pattern were 19.3％ and 5.7％, respectively, while the spatial variation explained by these two factors together was 60.8％. Therefor e, the coupling effect is obvious.