| Zoobenthos investigations in 21 sampling sites of the main stream of Shaying River, the largest tributary of the Huaihe River, were conducted in April, 2013 during the ecological rehabilitation of this river. A total of 38 species (20 species of aquatic insects, 3 species of crustaceans, 2 species of oligochaetes, 11 species of molluscs, and 2 species of other genera), were recorded, belonging to 4 phyla, 7 classes, 15 orders and 31 families, with the average density, biomass, species number of per site, Shannon-Wiener index, Margalef index and the average Pielou evenness index being 242.40ind./m2, 291.33g/m2, 7.6 species per site, 1.20, 1.56, and 0.52, respectively. Bellamya purificata, Cficotopus sp., Unio douglasiae and Parafossarulus eximius were the common species and Molluscs were the absolutely dominant group in most sampling sites, accounting for 64.74% of the total individuals. The benthonic animals in all sampling sites were divided into eight groups by clustering analysis, which were obviously separated from each other, indicating that the spatial heterogeneity of zoobenthos community was high. The similarity percentage analyses (SIMPER) indicated that Bellamya purificata, Cricotopus sp., Palaemonidae sp., Limnodrilus sp., Parafossarulus exirnius and Chironomus sp. were the major species contributing to the spatial variability of zoobenthos community were. In addition, the analysis of water quality based on the community structure of benthonic animals showed the water quality of the reaches above Zhoukou floodgate was obviously better than that of below Zhoukou floodgate, and the water quality of the reaches below Zhoukou floodgate was improved compared to the past, which was consistent with the results of water quality monitoring based on physical and chemical parameters in recent years. |
