Characteristics of Spatial and Temporal Distribution of Benthic Fauna Communities in the Backbone Water Supply Channel of Taihu Lake Basin and Their Relationship with Environmental Factors

In order to reveal the spatiotemporal distribution of benthic macroinvertebrates together with their connections to environmental factors of Taipu and Wangyu River in Taihu Lake Basin, benthic macroinvertebrate communities were investigated from sediments of Taipu River (four sampling sites) and Wangyu River (five sampling sites) across four seasons. Community structures were analyzed to determine significant relationships with environmental factors using Redundancy Analysis (RDA) and Canonical Correspondence Analysis (CCA). Totally 19 species assigned to 11 families from 7 orders were identified from two river sediment samples. The results show highly dissimilarities between communities from Taipu River and Wangyu River, Bellamya aeruginosa and Bellamya purrificata dominated benthic macroinvertebrate community in Taipu River and Bellamya purrificata and Limnoperna fortunei dominated in Wangyu River. In spite of dissimilar communities from two rivers, no significant differences were examined for benthic macroinvertebrate density, biomass and diversity indexes. Meanwhile, significant differences were found for density across sampling sites and diversity indexes among four seasons in Taipu River. CCA indicates that, environmental factors including conductivity (spring), water temperature (summer), pH (autumn) and dissolved oxygen (winter) were environmental driving factors for community structure of benthic fauna communities in Taipu River, whereas water temperature and total phosphorus concentration (spring), COD_Mn (summer), dissolved oxygen (autumn) and water temperature (winter) were environmental driving factors for community structure of benthic fauna communities in Wangyu River.