Benthic Diatom Assemblages Distribution in Longjiang River,in Relation to Environmental Factors

In September 2013,diatom assemblages were collected from 20 sites in Longjiang River Basin. Altogether 30 genera and 163 species were identified. Community characteristics of diatom analysis showed that the diatom relative density of upper reaches was greater than the downstream,and the water quality was relatively good,changes in water quality and the number of species showed no obvious regularity. RDA analysis showed that eight environmental factors explained 51.3 %of the variation in the diatom community,and filter out dissolved oxygen,temperature,conductivity and altitude,as several significant factors which influence the community variability and spatial distribution of the diatoms,could explain 30.9%variation in the diatom community structure,accounting for 60.23% of the total amount of environmental factors. Diatoms relative density,the number of diatom species and environmental factors related to correlation analysis,cluster analysis and regression analysis showed that there is no significant correlation between the number of diatom species and environmental factors,but diatoms relative density with altitude there is a significant correlation.