Community structure of alpine sparse vegetation and effects of micro-topography in Pushila,Everest-Choyu region,Tibet,China
西藏珠峰－卓奥友峰普士拉地区高山稀疏植被的群落特征及小地形的影响

A total of 13 plots were set along a transect from the altitude of 5176 m to 5390 m in Pushila, Everest-Choyu region, Tibet, to investigate community structure of alpine sparse vegetation and effects of micro-topography. A total of 80 higher plant species, belonging to 47 genera, were identified. The most prevalent species were Kobresia pygmaea, Lagotis humilis, Potentilla cuneata, Pedicularis oederi var. sinensis, Potentilla polyschista, and Arenaria densissima. Several genera were highly species rich, such as Saxifraga, Saussurea, Kobresia, Potentilla, Gentiana, and Draba. As altitude decreased, richness of both species and genera tended to increase. Vegetation coverage was found to be a good indicator for habitat conditions. Cluster analysis supported this finding. With increasing vegetation coverage, transformed species richness (TSR) and transformed genus richness (TGR) increased, while Shannon-Wiener index decreased. Four habitat types that reflected a good correlation between community structure and micro-topography were identified based on CCA analysis using species matrix and five variables (altitude, slope, aspect, soil depth, and vegetation coverage).