Macroinvertebrate community structure and the biological assessment to the water quality of Wujiang river
乌江流域大型底栖动物群落结构及其水质生物评价

An investigation was conducted in 34 sections of mainstream and 16 tributaries of Wujiang River of Guizhou Province in July-August 2006 in order to study the community structure of macroinvertebrate and water quality. Biology Pollution Index (BPI), Goodnight-Whitley Index (GI) and Shannon-Wiener Index (H ) were applied to assess water quality. It was found that there was 132 macroinvertebrates species belonging to 54 families, 7 classes and 4 phyla. These macroinvertebrates including 1 species of nematoda, 21 species of annelidas, 37 species of mollusks and 73 species of arthropods, and molluscs (28.03%) and aquatic insects (53.78%) were dominant groups. The density of macroinvertebrates was 22-21712 ind/m2 in the river basin. As dominant species, Limnodrilus hoffmeisteri and Gyraulus convexiusculus showed relatively high densities. The biodiversity was quite high in Wujiangdaqiao, Shatuodianzhan, Yanheerqiao, Siqu sections (H =2.97~3.56). The types of macroinvertebrates community including Mollusca or mainly Mollusca, Mollusca + Arthropoda or mainly Mollusca + Arthropoda, mainly Annelida, Arthropoda + Annelida or mainly Arthropoda, and Mollusca were dominant groups in majority community in the river basin. The biologic assessment of water quality suggested that 21 sections were contaminated from light to medium on BPI, 31 sections were contaminated from medium to severe on H , 34 sections were contaminated from light to severe on G.I. Therefore, it is very important to control pollution sources in order to improve Wujiang river water quality.