| In recent years, increasing aquiculture, reclamations and hydraulic engineerings is widespread in the lakes in middle and low floodplain of Yangtze River, resulting in accelerating eutrophication and wetlands degradation. Macrozoobenthos as important fishery resources are prone to be exploited. In order to have an insight into the macrozoobenthic community in response to the disturbance imposed on the lake wetlands, we surveyed the density and biomass of the macrozoobenthos on 49 sampling sites in different lake regions of Caizi Lake group, Anqing City, Anhui Province for seven times in 2008 and 2009.We surveyed the density and biomass of the macrozoobenthos at 49 sampling sites seven times, including twice in spring, summer, autumn respectively, and one time in winter. We sampled twice at each sites using improved 1/16 m2 Peterson Catcher. After classifying, we count and weigh for the population of each site. One Way-Anova Analysis was used to analyze the spatio-temporal changes of the macrozoobenthic density and biomass in the three lake regions. We analyzed the community structure using Clustering Analysis in different fishery regions. Biodiversity was indicated with Shannon-Wiener index, and the pollution state of different lake regions with GI, BPI, HBI index.A total of 39 macrozoobenthic species were found, of those the dominant species were Tendipes sp., Branchiura sowerbyi, and Alocinma longicornis. And the species in Baitu Lake and Caizi Lake were dominated by mollusca, while in Xizi Lake by arthropoda.The average macrozoobenthic density was 55.20±76.25 ind./m2 and the average biomass was 19.56±65.37 g/m2. The average density was 63.43±52.76,36.44±34.49 and 79.77±118.90 ind./m2, and the average biomass was 17.48±28.24,21.70±39.44 and 4.94±18.46 g/m2 in Baitu Lake, Caizi Lake and Xizi Lake respectively. The average density and biomass of Arthropoda was significantly higher in Xizi Lake than those in Baitu Lake (P<0.01) and Caizi Lake(P<0.01). But the average density and biomass of Mollusk was significantly lower in Xizi Lake than those in Baitu Lake(P <0.01) and Caizi Lake(P<0.01). Clustering Analysis showed high similarity of macrozoobenthic community between Baitu Lake and Caizi Lake. Shannon-Wiener indice were 2.25,1.71 and 1.44 in Baitu Lake, Caizi Lake and Xizi Lake respectively.GI, BPI and HBI index showed that the water quality was clean, slight-moderate or moderate pollution in polyculture zones for crab, black and bighead crap in Baitu Lake, and slight, slight-moderate or moderate pollution in two polyculture zones in Caizi Lake, while moderate, slight-moderate or serious pollution in two polyculture zones of Xizi Lake respectively. The water pollution state in Baitu Lake was similar with that in Caizi Lake, both of them were better than in Xizi Lake. Hilsenhoff index was susceptive than both Goodnight-Whitley index and Biology Pollution index.Compared with the indice in 2001, Macrozoobenthic diversity decreased, and the dominant species have changed. Macrozoobenthic community structure has changed on the pressure of anthropogenic interference, such as aquiculture. A sustainable fishery model was needed for the biodiversity conservation of the lake wetland.
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