Community Diversity of Alpine Rhododendron in Qomolangma National Nature Reserve

Based on field survey data,we studied classification and ordination of Alpine rhododendron community by the methods of TWINSPAN and DCCA,and analyzed distribution pattern of species diversity along the elevation gradient in Qomolangma National Nature Reserve.The results showed that:(1)38plots included 135 species vascular plants in this Nature Reserve,belonging to 68 genera and 35 families,respectively.The most prevalent species were Kobresia pygmaea,Polygonum viviparum,Euphorbia stracheyi,Rhododendron anthopogon,R.nivale,Cassiope fastigiata,R.lepidotum,Anaphalis xylorhiza and R.setosum.(2)38 plots of alpine rhododendron community were classified into 14 types of plant association.(3)According to two-dimensional DCCA ordination diagram,the soil type and altitude are the main factors of affecting distribution pattern of Alpine rhododendron community in this area.(4)Species richness S,Shannon Wiener index and Simpson index of Alpine rhododendron community declined significantly along the altitude gradient,but there is no significant correlation between Pielou index and altitude in this area.