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)24plots 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)24plots 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.parvifoliacommunity and species in this area.(4)As altitude increased,species richness,Shannon-Wiener indexand Simpson index of P.parvifoliacommunity 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.