Effect Of Coastal Reclamation On Intertidal Macrobenthic Community Structure In Jiaolai Estuary Of South Laizhou Bay

Based on the data of macrobenthos at 9 stations in the intertidal zone of Jiaolai River in the south of Laizhou Bay from 2014 to 2017,The diversity indexs,abundance and biomass curve,AMBI and M-AMBI index were used to evaluate the species composition,dominant species,abundance,biomass and community structure of the macrobenthos,in order to evaluate the ecological environment quality of the study area.The main results are as follows: There were 29 species of benthic animals identified from 2017 to 2014,belonging to 5 phylums,6 classes,23 families.Molluscs were the dominant group,accounting for 65.52% of the total species number.There are 5 species of crustaceans,4 species of Annelida,1 species of brachiopod.There were 29 species in 2016,25 species in 2014,24 species in 2017,and 21 species in 2015.The average abundance was 143.69 ind./m2 in 2014,132.79 ind./m2 in 2015,89.81 ind./m2 in 2016,20.25 ind./m2 in 2017;The average abundance of Molluscs was 93.20 ind./m2 in 2014,92.06 ind./m2 in 2015,91.25 ind./m2 in 2016,88.72 ind./m2 in 2017.The average abundance of Annelida was 6.37 ind./m2 in 2017,3.94 ind./m2 in 2015,3.44 ind./m2 in 2016,2.42 ind./m2 in 2014.The average biomass was 46.14 g./m2 in 2014,40.02 g./m2 in 2015,31.90 g./m2 in 2016,8.81 g./m2 in 2017;The average biomass of Molluscs was 42.83 g./m2 in 2014,36.44 g./m2 in 2015,28.08 g./m2 in 2016,7.72 g./m2 in 2017.The average biomass of Annelida was 0.24 g./m2 in 2017,0.48 g./m2 in 2016,0.57 g./m2 in 2014,0.72 g./m2 in 2015.The Molluscs abundance and biomass accounted for the highest proportion,followed by brachiopods and Annelida.Bray-Curtis similarity cluster analysis and NMDS multidimensional ordination analysis showed that the stability of macrobenthic community structure was poor from 2014 to 2017.And the dominant species were M.incongrua,Moerellarutila,Umboniumthomas and Lingula.It was worth noting that the only dominant species is Arenicola cristat in 2017 at the season of autumn.In a word,the abundance and biomass have been reduced from 2014 to 2017,and the community structure also had changed greatly after the reclamation,which indicated that the reclamation has had a bad effect on the macrozoobenthic community structure.The the biomass abundance curve,and the AMBI index were used to evaluat the habitat ecological environment,the results showed that the macrozoobenthic community structure were disturbed slightly before the project,the quality of the ecological environment was higher or better,and the community structure were serious after the project.Both of the two results showed that the ecological health of the macrozoobenthos community after the project was poor,which showed that the reclamation had a bad effect on the ecological environment of the macrozoobenthos community.At the same time,it also showed that the two methods can respond sensitively to the spatial and temporal changes in the study area,which was suitable for evaluating the quality of the macrozoobenthos community in the intertidal zone of the Jiaolai estuary in the southern Laizhou Bay.