Community Characteristics of Alpine Shrub Salix oritrepha

Salix oritrepha,belonging to the Salix,Salicaceae,is a perennial shrub endemic to China.According to the data of field plot,this paper deals with preliminary characteristics of S.oritrepha shrub communities in source regions of three rivers.The results show that:there are about 97 spermatophyte species,among which there are 30 families and 60 genera in S.oritrepha shrubs.There are 10 species of shrubs and 87 species of herbs.The dominant species is S.oritrepha,and the companions are Potentilla fruticosa,Caragana jubata and Potentillaglabra ect.The temperate floristic elements occupy a dominant position.The main life form of plants is hemicryptophytes(52.59%).The vertical structure is obvious and can be commonly divided into two layers:the shrub stratum and the herb stratum.The species diversity index of the shrub layer was a bit low,and the general trend was herb layershrub layer.