Macrozoobenthic Community Structure And Water Quality Bioassessment Of Four Rivers In Western Hubei Province

The western Hubei province is a national water source reserve and important ecotourism area.To understand the ecological health status of river system,a field survey on the macrozoobenthic community structure and water quality bioassessment was carried out in Juanqiao river(J),Lichun reach of Qingjiang river(Q),Huangbo river(H)and Yunxi reach of Tianhe(T)from October 2014 to January 2017.This study would shed a light on ecological status of river protection and restoration in the western Hubei province.The main findings were as follows:(1)We conducted a field survey on the macrozoobenthic community structure and water quality bioassessment in Lichuan Reach of the Qingjiang River from May 2016 to March 2017.The total nitrogen and phosphorous along water flow direction increased.A total of 61 macrozoobenthic families were collected,belonging to 5 phyla,8 class,and 16 orders.Ephemeroptera accounted for 74.1% and 41.6% of the total abundance in Q1 and Q2,respectively,and in Q3,Q4 and Q5,Decapoda accounted for 73.5%,79.9% and 54.5%,of the total abundance respectively.The abundance of Ephemeroptera decreased noteable along water flow direction from Q1 to Q5.Several common rapid bioassessment indices including SIGNAL,FBI,BPI,EPT-Fa,shannon-wiener index,margalef index and pielou evenness index were chosen to evaluate the biological health status.Compared with other indices,FBI and SIGNAL had better repression relationship with the first axis of PCA,indicating better applicability.The correlations were significant between the two indices,which showed similar consistency of the indices in river health bioassessment.However,SIGNAL index showed better repression relationship with pollution trend along water flow direction.Our results indicated that FBI and SIGNAL index was suitable for biological evaluation of water quality in Lichuan Reach of Qingjiang River.(2)A further field survey on the macrozoobenthic community structure and water quality bioassessment was carried out in J,Q,H and T rivers from October 2014 to January 2017.From upstream to downstream,Leptophlebiidae,Atyoidae and subfamily Chironominae were the dominated group in J1,J2 and J3 sites,respectively.Heptageniidae accounted for 55.0% of the total abundance in Q1;Corbiculidae accounted for 83.8% and 64.8% in Q2 and Q3,respectively;Viviparidae was the most dominated group in Q4 while strong tolerance Tubifex occurred.Tubifex and subfamily Chironominae accounted for 49.5% in Q5.The trend analysis of tolerance sensibility along water flow direction was decreased in J,Q and T,indicating water quality degradation.However,the pollution-sensibility group were dominated in all seven sampling sites of H,indicating a good water quality.FBI and SIGNAL indices also showed good repression relationship with the first axis of PCA.The results indicated FBI and SIGNAL index were suitable for water health bioassessment index in western Hubei Province.Our results showed the sensitive macrobenthos groups were the dominant in the source and upsteam.However,the sensitive groups gradually reduced or disappeared along water flow direction,indicating the pollution increased.The results also indicated FBI and SIGNAL indices were suitable for water health bioassessment index in wstern Hubei Province.