Community Structure Characteristics Of Macrobenthos In The Coastal Waters From Changli,Hebei Province

Macrobenthos is vital for marine ecosystem,and a most complex group in ecology,it plays a role as a key for substance circulation,energy flow,marine environmental monitoring and ecological restoration.Based on the macrobenthos data in spring and summer of 2017 and 2018 from Changli Gold Coast National Nature Reserve in Hebei Province,the changes of community structure were analyzed.The resource status of Branchiostoma belcheri tsingtauense resources in the Changli sea area was investigated;Diversity index(H'),ABC curve method,AMBI index and M-AMBI index were used to evaluate the health and habitat quality of macrobenthos communities in the protected areas,and the applicability of different indexes in protected areas was compared and analyzed;The relationship between macrobenthos community structure and environmental factors was studied by BIOENV analysis and Pearson correlation analysis.(1)The results showed that 79 species of macrobenthos were identified in 2017 and 121 species of macrobenthos were identified in 2018,and the species were mainly composed of annelids.Branchiostoma belcheri tsingtauense was the absolute dominant species in the survey area.The average abundance of macrobenthos was 87.11 ind./m2 and the average biomass was 11.13 g/m2 in Changli sea area in 2017;and the average abundance of macrobenthos was 105.26 ind./m2 and the average biomass was 5.68 g/m2.Compared with 2017,the abundance of Macrobenthos in the coastal waters of Changli has an upward trend,while the biomass has a downward trend.Macrobenthos could be divided into five groups at 23%similarity level in spring,2017;five groups at 32%similarity level in summer,2017;five groups at 24%similarity level in spring,2018 and four groups at 31%similarity level in summer,2018.The similarity coefficient between groups was low.(2)In 2017,the average abundance of Branchiostoma belcheri tsingtauense was 30.98 ind./m2 and the average biomass was 1.40 g/m2,in 2018;the average abundance of Branchiostoma belcheri tsingtauense was 53.80 ind./m2 and the average biomass was 1.40 g/m2.The ?-age and ?-age Branchiostoma belcheri tsingtauense dominated in the Changli reserve sea area,and they alternately took the lead;the dominant body weight of Branchiostoma belcheri tsingtauense was 0-20 mg and 20-40 mg.Through the comparative analysis of Branchiostoma belcheri tsingtauense abundance graphs,it was found that Branchiostoma belcheri tsingtauense habitat intensive areas had a migration trend.(3)Diversity index(H),ABC curve method,AMBI index and M-AMBI index were used to evaluate the health and habitat quality of macrobenthos communities in the protected areas.The results showed that there were some differences among the results of different evaluation methods.In general,the quality of macrobenthos habitats in 2018 was better than that in 2017,and the quality of macrobenthos habitats in the core areas of protected areas was better than that in buffer areas.After specific application and comparative discussion,M-AMBI index had better applicability.(4)BIOENV analysis showed that sediment organic carbon content had a profound impact on macrobenthos communities in the coastal waters of Changli;Pearson correlation analysis showed that macrobenthos abundance was positively correlated with water depth in springs 2017;biomass and water depth were negatively correlated in summer,2017.The abundance and biomass of macrobenthos in other voyages were not significantly correlated with environmental factors.