The Study Of Aquatic Biodiversity And The Evaluation Of Ecosystem Health In Huanghe River Upper Reach From Longyangxia To Liujiaxia

According to the aquatic biodiversity data during 2005-2008 in Huanghe upper reach from Longyangxia to Liujiaxia,compared with the histroy data,the species,population quantity,Shannon-Weaver index,and the changes of these indexes were analyzed and discussed.And on this basis,the river ecosystem health was evaluated.The results showed that 35 species of fish in the reach from Longyangxia to Liujiaxia and the most of them were cyprinidae,which had 16 species.The secondly were loaches, which had 13 species.Compared with the history data,the species of fish reduced 7 species and added 14 species.The aboriginal fish population takes on downtrend and the foreign fish population takes on uptrend.There were 7 phyla and 116 species of phytoplankton by microscopy,and most of them were chlorophyta,the secondly were diatom.The dominant species were Synedra,Nitzsschia closterium,Navicula,Closterium,Schroederia and Ceratium.The quantity of phytoplankton was 0.06×10~4～12.08×10~4 ind./L,the density of phytoplankton was 0.0009～0.3029mg/L. Indicator organism and biological diversity indices are used to evaluate the degree of water quality.The results shows that the water quality is low-grade polluted.There were 4 classes and 50 species of zooplankton by microscopy,and most of them were protozoa,which had 24 species.The secondly were rotifer,which had 18 species.The quantity of zooplankton was 1.2～1174 ind./L and the density of zooplankton was 0.00006～0.3926mg/L.The ecosystem health of reach from Longyangxia to Liujiaxia had been evaluated by fish IBI,diversity index of plankton,water quantity and water quality.The results showed that the ecosystem health was in the level of sub-health conditions.The main factors effected the ecosystem health were the vegetation degradation of riparian zone,the development utilization of water resources too high,the survival conditions of aboriginal fish poor.