Community structure and biological integrity of periphyton in the Weihe River Basin, China
渭河流域河流着生藻类的群落结构与生物完整性研究

In this work, the community structure of periphyton and characteristics of environmental factors among 45 sample sites in the Weihe River Basin, Northwest China, were investigated. Using the periphyton assemblages, we assessed stream conditions of Weihe River based on Periphyton Index of Biological Integrity (P-IBI). The results indicated that there were great differences in the periphyton community structure in Weihe River. Canonical correspondence analysis (CCA) showed that conductivity and flux significantly influenced the community structure of periphyton in Weihe River basin. The results of P-IBI showed that upstream and right tributary area of main Weihe River were in excellent ecological integrity, whereas the downstream and left tributary area of main Weihe River were in severe impairment. Though the biological integrity of periphyton in Jinghe River and downstream of Luohe River was in severe integrity, the upstream of Luohe River was in relatively good biological integrity. In this paper, we also discussed the relationship between environmental factors and periphyton community, and analyzed the possible reasons that caused the variation in biological integrity of periphyton community in the Weihe River Basin.