Community structure of macrozoobenthos and the evaluation of water environment in Lake Taihu

Abstract

To characterize the community structure of macrozoobenthos and to examine their relationships with environmental factors,macrozoobenthos were investigated at 116 sites of Lake Taihu in winter and summer of 2014. A total of 55 species were recorded,belonging to 3 phyla,7 classes,18 orders and 27 families. The mean density and biomass of macrozoobenthos were 405. 5ind. / m2 and 146. 6 g / m2,respectively. Corbicula fluminea,Bellamya aeruginosa,Limnodrilus hoffmeisteri,Grandidierella aihuensis,Nephtys oligobranchia and Paranthura sp. were the dominant species in Lake Taihu. The 116 sampling sites were classified into three groups based on cluster analysis using environmental factors. One-way ANOVA showed that environmental factors differed significantly among the three groups. Analysis of similarities and non-metric multidimensional scaling showed that macrozoobenthic assemblages exhibited remarkable difference among the three groups. Canonical correspondence analysis demonstrated that macrozoobenthic community structure was highly correlated with habitat-specific differences in water depth,total nitrogen,total phosphorus,ammonium nitrogen,macrophytes,dissolved organic carbon and Φ50. From the east and southwest to the north area of Lake Taihu,the diversity indexes of macrozoobenthos decreased but the density and biomass increased with the increase of trophic status index. Our results showed that the trophic level,bottom sediment type and macrophytes coverage were the key factors regulating community structure and diversity of macrozoobenthos.