【摘要】 中国西南干旱河谷植被是我国西南横断山区特有的植被类型,目前关于西南干旱河谷植被还没有整体性的群落类型划分研究。根据对甘肃、四川、云南三省九条主要河流的干旱河谷段野外调查和文献来源的1,339个植物群落样方数据,采用自适应仿射传播聚类方法,对我国西南干旱河谷的植物群落进行数量分类,并采用典范对应分析方法进行排序分析。结果表明:(1)调查样方的植物群落分为7个植被型(稀树草原、肉质灌丛、常绿阔叶灌丛、暖性落叶阔叶灌丛、常绿硬叶林、落叶阔叶林和暖性针叶林),24个群系,31个群丛类型。暖性落叶阔叶灌丛是本植被区的代表性植被类型;分布最广的群系为鞍叶羊蹄甲灌丛(Form.Bauhinia brachycarpa,样方比例50.9%)、黄茅灌草丛(Form.Heteropogon contortus,样方比例11.9%)、孔颖草灌草丛(Form.Bothriochloa pertusa,样方比例5.6%)、黄荆灌丛(Form.Vitex negundo,样方比例4.2%)、知风草灌草丛(Form.Eragrostis ferruginea,样方比例3.8%)、车桑子灌丛(Form.Dodonaea viscosa,样方比例3.4%)、云南松疏林(Form.Pinus yunnanensis,样方比例3.3%)。(2)冬季低温和降水的季节性是限制干旱河谷植物群落分布的主要气候因子。稀树草原、肉质灌丛是典型的干热河谷植被类型;暖性落叶阔叶灌丛、常绿硬叶林、常绿阔叶灌丛是干暖河谷植被的优势类型;暖性针叶林、落叶阔叶林则主要在干温河谷环境占优势。更多还原

【Abstract】 The vegetation in dry valleys of Southwest China is characterized by unique vegetation type. Based on plant community sample data(1,339 plots) collected for 9 valleys in Gansu, Sichuan and Yunnan provinces, we used an adaptive affinity propagation method for quantitative classification, and performed an ordination using canonical correspondence analysis. Results showed that the plant communities can be divided into 7 vegetation types(savanna, succulent thicket, evergreen broadleaved thicket, warm deciduous broadleaved thicket, evergreen sclerophyllous forest, deciduous broadleaved forest, warm needle-leaved forest with 24 formations and 31 associations. The most representative vegetation type was the warm deciduous broadleaved thicket, while the most common formations were Form. Bauhinia brachycarpa(50.9%), Form. Heteropogon contortus(11.9%), Form. Bothriochloa pertusa(5.6%), Form. Vitex negundo(4.2%), Form. Eragrostis ferruginea(3.8%), Form. Dodonaea viscosa(3.4%) and Form. Pinus yunnanensis(3.3%). Mean temperature of the coldest month and precipitation seasonality are two dominant climatic factors, which limit the distribution of plant community types in the dry valleys. Savanna and succulent thicket are the dominant vegetation types in typical dry-hot valleys. Dry-warm valley are dominated by warm deciduous broadleaved thicket, evergreen sclerophyllous forest and evergreen broadleaved thicket. Warm needle-leaved forest and deciduous broadleaved forest are more adaptive to lower temperatures.更多还原