Fluvial Benthic Macroinvertebrate Community Characteristics And Water Quality Bioassessment In Puyang River,Zhejiang Province And South Area Of Jiangsu Province

River ecosystems are increasingly being disturbed by human-induced activities,which often result in river habitat destruction,water quality deterioration and biodiversity loss.Biomonitoring and bioassessment using benthic macroinvertebrates is an important means for the assessment of water quality and biodiversity protection of rivers,and is helpful for the river health management as well.Benthic macroinvertebrates and physicochemical variables were investigated from 26 sites in the Puyang River,Zhejiang,China in April 2016.Water quality was assessed by the Shannon-Wiener diversity index and biotic index(BI).We collected a total of 123 macroinvertebrates taxa,belonging to 104 genera,56 families,17 orders,7 classes,and 4 phyla.Among them,species richness and individual number of aquatic insects were the highest,in which Caenis sp.was the dominant species.The richness and number of collector-gatherers and intermediate species were the main components in terms of functional feeding groups and species sensitivity to stressors respectively.Spearman correlation analysis shows that Shannon-Wiener diversity index was significantly negatively correlated with chemical oxygen demand(CODCr)(r=-0.515,P=0.007)and total phosphorus(TP)(r=-0.665,P=0.000).BI was significantly positively correlated with CODcr(r=0.406,P=0.040)and TP(r=0.704,P=0.000).Canonical correspondence ordination analysis(CCA)shows that TP,Zn,CODcr,water temperature(WT),and pH were the major contributors to the macroinvertebrate community structure.Ephemeroptera and Oligochaeta were the main indicators responding to environmental changes.Both Shannon-Wiener diversity index and the biotic index show that water quality of the Puyang River was in slightly or moderately polluted condition in general.The water quality of mainstem was slightly better than tributary,and the water quality of upstream was clean,but a few sites in middle and lower stream were heavily polluted condition.Our study revealed that water pollution was the major driver in structuring macroinvertebrate community composition and structure at Puyang River,and suggested macroinvertebate community could recover following the decline of pollutant concentration such as TP and CODCr in the water.Benthic macroinvertebrates and environmental variables were collected from 86 rivers of southern Jiangsu in November,2016.Water quality was assessed using the biotic index(BI).A total of 80 macroinvertebrates taxa,belonging to 76 genera,39 families,17 orders,6 classes,and 3 phyla,were found.Limnodrilus hoffmeisteri was the dominant species.Spearman correlation analysis showed that BI index was negatively and significantly correlated to DO(r=-0.356,p=0.001),but positively and significantly correlated to TP(r=0.335,P=0.002),TN(r=0.447,P=0.000)and COND(r=0.436,P=0.000).Canonical correspondence ordination analysis(CCA)showed that TP,DO and COND were the major contributors to the variation of benthic macroinvertebrate composition.BI index showed that of the 46.5%investigated rivers were moderately polluted.DO in Puyang River was significantly higher than that of southern Jiangsu,but CODMn and TN was significantly lower than those of southern Jiangsu.The results of NMDS and ANOSIM showed that there was a significant difference in the composition of benthic macroinvertebrate community in urban rivers between Puyang River and southern Jiangsu.The species greatly contribute to the difference between Puyang River and rivers in southern Jiangsu were Cricotopus sp.,Limnodrilus hoffmeisteri and Caenis sp..The biotic index shows that water quality in urban rivers of the Puyang River was better than southern Jiangsu.