Health Assessment Of Marshwetlands In The Sanjiang Plain Using Index Of Biotic Integrity Of Aquatic Invertebrates

Sanjiang Plain is a concentrated distribution area of freshwater marsh wetlands in the northeast of China.It is an important ecological resource and environmental protection barrier.With the changes of the environment and the influence of human activities,the wetland has been seriously degraded and lost,the function of the wetland ecosystem has been degraded,and health has been seriously threatened.In the spring,summer and autumn of 2017,21 samples of aquatic invertebrates were investigated and sampled.Analyze the structural characteristics of aquatic invertebrate species in wetlands.Based on the survey data,an aquatic invertebrate integrity index was constructed in Sanjiang Plain Agricultural Wetland Ecological Area to evaluate the ecological health status of swamps in the Sanjiang Plain.During the study period,a total of 6395 aquatic invertebrates were collected,belonging to 3 families,7 classes,16 orders,54 families and 93 species.The main groups were mainly aquatic insects and gastropods.Among them,aquatic insects accounted for 70.21% of the total species.Among aquatic insects,Coleoptera,Diptera,and Acarina are dominant,accounting for 29.41%,22.06%,and 16.18%,respectively.The main dominant species are: Parafossarulus striatulus,Siberian vivarium,Sagementina nitida,Cipangopaludina ussuriensis,Bithynia ussuriensis,Gyraulus centrifugus,Chironominae sp.,sigara sp.,and Coenagrion sp.There are certain differences in dominant species in different seasons.This study indicates that,the aquatic invertebrate community shows a large difference in species composition between non-identical points.The density of aquatic invertebrates in wetlands is relatively low,especially after the wetlands of the marsh have been disturbed,and the density has dropped significantly.The level of aquatic invertebrate species diversity is overall higher,but there is no significant difference between the same points.The final aquatic invertebrate integrity index including 4 metrics of total taxa(M1),%Helicobacter(M17),%Dragonidae(M27),and %Chironomidae(M30).The values of metrics were calculated through 3-point method and ratio scoring method,and the values of Aquatic Invertebrates Integrity Index were calculated as sum of the 4 biological indexes.The discriminant ability analysis shows that the IQ values of the aquatic invertebrate integrity index values calculated by these two methods are all 3,which can better distinguish the reference wetland and the damaged wetl and,and has a good correlation(r=0.9436).Through calculation and comparison,the health standard established by the ratio method is better than the 3-point method for evaluating the accuracy of reference wetlands and damaged wetlands.Based on this,the 25% quantile value of reference wetland was regarded as a health reference value.No interference was determined when the value was no less than 25% quantile value.As to the values of aquatic invertebrates integrity index that was less than 25% range of 3 aliquots to established aquatic invertebrate integrity index health assessment criteria of Sanjiang Plain: >2.69 for non-impaired,1.79 ~ 2.69 for slight-impaired,0.9~1.79 for moderate-impaired,and 0~0.9 for severe-impaired.The results showed that 71.43% of the marsh wetlands in the Sanjiang Plain were different degrees of disturbed,and 42.86% by the moderate to severe interference,28.57% belong to no interference.