Community Structure Of Macrozoobenthos And Assessment Of Water Quality In Xiannv Lake Basin

Lake Xiannv(Formerly known as Jiangkou Reservoir),located in Xinyu city. It was founded in 1958. Lake Xiannv is not only the famous scenic spot, but also the mean source of drinking water in Xinyu city. For better understanding of the commumity structure of zoobenthos in Xiannvlake, the annual dynamics of macrozoobenthos community,dominate species, eviromental factors was studied, and assessed the quality of water in the Xiannv Lake and the main inflowing rivers from May, 2014 to May, 2015, in order to provide theoretical basis for the environmental protection in this important zone. The main conclusions in this research are the following:1.In total, 116 taxa belonging to 3 phyla, 55 families and 78 genera were identified. Totally, 43 taxa belong to mollusca, 62 taxa belong to arthropoda, and 10 taxa belong to annelida. The dominant species were Tubifex sinicus, Bellamya purificata, Corbicula fluminea, Neocaridina denticulate, Tendipesplumosus sp.,Pelopia sp., Procladius sp. and Limnodrilus hoffmeisteri.2. The annual average density and biomass of macrozoobenthos was 346 ind./m2 and 54.26 g/m2 in Lake Xiannv, respectively. There was a significant difference in density and biomass among different seasons and areas(P<0.05). Density in river area reach the highest, averange 722 ind./m2 and in lake reach the lowest, averange 251 ind./m2. Density in January reach the highest, 567 ind./m2 and in May reach the lowest 163 ind./m2.3. Lake area has lower substrate stability, river area has higher substrate stability.Annelida was dominant in lower substrate stability and mollusca was dominant in higher substrate stability.4. Using Simpson's diversity ind.ex, water quality in different areas was assessmented, which showed that inflowing rivers and Lake Qianyang, the upstream lake zone of Xiannv Lake, was slightly polluted and Lake Wulong, the downstream one, was moderately polluted. The structure of zoobenthos in rich nutritional water is sample and the structure of zoobenthos in poor nutritional water is complex.5. The results of cluster analysis and MDS showed that the distribution of macrobenthos had obvious environment and spatial heterogeneity, 2 stastion groups were divided, the lake area commmunity and the river area community.