西藏拉萨河谷巴嘎雪湿地植被群落组成及其环境因素之间的相关性

文章以拉萨市巴嘎雪湿地作为研究地点，采用趋势对应分析（DCA）和典范对应分析（CCA）对该湿地植被群落结构、分布格局及其环境条件的相关性进行了研究。其结果表明，巴嘎雪湿地34种主要植物隶属18科32属，其中常见的种有芦苇、肉果草、嵩草、杉叶藻、狐尾藻、水毛茛、矮嵩草、荸荠、西藏粉报春和甘肃马先蒿等。DCA分析表明，26个样方分为三个主要组合类型，分别代表不同的生境类型；34个植物物种分为三种主要的群落类型并与CCA排序分析基本一致。CCA排序分析反映了巴嘎雪湿地植被群落结构和分布格局随着环境变化趋势形成不同物种为代表的三个群落，并且CCA分析确定了影响该湿地植被群落结构和分布格局的主要环境因子，即水位变化、电导率和小生境变化（小丘、积水等）等。

Correlation between Composition and Distribution of Vegetation and Environmental Factors in Bagaxue wetland, Lhasa

The correlation between vegetation composition, their distribution and environmental factors of Bagaxue wetland was studied by using DCA and CCA. The results showed that the major 34 plant species in the wetland belong to 32 genera, 18 families and the commonest plant species include Lance tibetica, Kobresia spp., Hippuris V Eleocharis valleculosa, Primula tibetica, Pedicularis kansuensis and so on. DCA ordination showed three ecological species groups and three plot groups that represent three different habitats and are consistent with CCA ordination result. CCA direct gradient analysis effectively summarized the correlation between the vegetation composition and environmental variables in the wetland and CCA allowed detecting the most important factors namely water level, conductivity and microhabitats for affecting vegetation composition and their distribution in the wetland.