珠穆朗玛峰自然保护区小叶金露梅灌丛群落数量分类和排序及其多样性垂直格局

根据野外样方调查数据,采用双向种指示分析(TWINSPAN)和典范对应分析(CCA),对珠穆朗玛峰国家级自然保护区小叶金露梅灌丛群落进行分类和排序,并分析物种多样性沿海拔梯度的分布格局。结果表明:(1)该区域24个样地中,记载的维管束植物共有23科45属80种,出现频度较高的种有小叶金露梅(Potentilla parvifolia)、高山嵩草(Kobresia pygmaea)、木根香青(Anaphalis xylorhiza)、垫状点地梅(Androsace tapete)、藏沙蒿(Artemisia wellbyi)、垫状雪灵芝(Arenaria pulvinata)和柴胡红景天(Rhodiola bupleuroides)等。(2)经TWINSPAN等级分类将该区域小叶金露梅灌丛24个样地划分为10个群丛类型。(3)样地和物种CCA二维排序结果表明,海拔和坡位是影响该区域小叶金露梅灌丛群落和物种分布格局的主要环境因子。(4)该区域小叶金露梅灌丛群落物种丰富度、Shannon-Wiener指数和Simpson指数均随海拔升高呈下降的趋势,而Pielou指数呈上升的趋势。(5)样地中优势种小叶金露梅的盖度和高度沿海拔梯度呈显著下降趋势。

Numerical Classification,Ordination and Species Diversity along Elevation Gradients of Potentilla parvifolia Community in Qomolangma National Nature Reserve

Based on field survey data,we studied classification and ordination of Potentilla parvifolia community by the methods of TWINSPAN and CCA,and analyzed distribution pattern of species diversity along the elevation gradient in Qomolangma National Nature Reserve.The results showed that:(1)24 plots included 80 species vascular plants in this Nature Reserve,belonging to 23 genera and 45 families,respectively.The most prevalent species were P.parvifolia,Kobresia pygmaea,Anaphalis xylorhiza,Androsace tapete,Artemisia wellbyi,Arenaria pulvinata and Rhodiola bupleuroides.(2)24 plots of P.parvifolia community were classified into 10 types of plant association.(3)According to two-dimensional CCA ordination diagram,altitude and slope position are the main factors of affecting distribution pattern of P.parvifolia community and species in this area.(4)As altitude increased,species richness,Shannon-Wiener index and Simpson index of P.parvifolia community tended to decrease,but Pielou index showed a trend of rising in this area.(5)Coverage and height of dominant species (P.parvifolia) significantly reduce along an altitudinal gradient.