雅鲁藏布江中游河谷植物群落数量分类与排序

Quantitative Classification and Ordering of Plant Communities in the Middle Yarlung Tsangpo River Valley

为揭示雅鲁藏布江中游河谷植物物种组成、植物群落与环境因子之间的关系,本研究运用样方调查法对研究区开展植物群落调查,采用双向指示种分析(TWINSPAN)结合去趋势对应分析(DCA)和典范对应分析(CCA)方法,系统分析了物种组成、群落类型和影响植物群落的主要环境因子。结果表明:38个样地共记录维管束植物185种,隶属于47科118属,菊科、蔷薇科、禾本科和豆科为优势科;TWINSPAN分类将植物群落分成17个群丛类型;样地CCA排序表明海拔解释了群落格局变化5.8%,年降水量解释了5.5%,温度解释了4.8%;26个优势种和次优势种的CCA排序结果的分布特征与各群丛的分布特征具有较好的相似性。综上,海拔是影响雅鲁藏布江中游河谷植物群落组成和分布的主要环境因子,研究结果可为雅鲁藏布江中游河谷植物保护和植物群落的空间分布格局提供理论依据。

To reveal the relationship between plant species composition,plant communities,and environmental factors in the middle reaches of the Yarlung Zangbo River valley,plant community survey of the study area was made using the sample survey method.By employing the two-way indicators species analysis(TWINSPAN)method,combined with detrended correspondence analysis(DCA)and canonical correspondence analysis(CCA),we systematically analyzed the species composition,community types,and the major environmental factors that influence plant communities.The results showed that:A total of 185 species of vascular plants belonging to 47 families and 118 genera were recorded from 38 sample sites.Asteraceae,Rosaceae,Gramineae and Leguminosae were the dominant families in the study area.The TWINSPAN classification divides plant communities into 17 cluster types.CCA ordering of sample plots indicates that altitude accounts for 5.8%of the change in community pattern,annual precipitation accounts for 5.5%,and annual average temperature accounts for 4.8%.The distribution characteristics of the CCA sorting results of the 26 dominant and subdominant species have good similarity with the distribution characteristics of the clusters.In conclusion,elevation is the main environmental factor affecting the composition and distribution of plant communities in the middle reaches of the Yarlung Tsangpo River valley,and the results of the study can provide a theoretical basis for the conservation of plants and the spatial distribution pattern of plant communities in the middle reaches of the Yarlung Tsangpo River valley.