启东长江口围填海工程对大型底栖动物的影响

为研究启东长江口围填海工程对大型底栖动物的影响，于2019年春季和夏季对围填海工程外侧水域大型底栖动物进行调查，分析群落结构特征、多样性指数及其与环境因子的关系。结果表明：2019年共采集大型底栖动物40种，其中围填海建造的围堤近侧和离岸20 km以外辐射的外侧海域分别采集到大型底栖动物19种和29种；近侧海域和远侧海域的优势种分别为7种和10种，春、夏季共有优势种分别为伶鼬榧螺Oliva mustelina和异足索沙蚕Lumbrineris heteropoda，优势类群为软体动物和环节动物，并且出现小型化、单一化趋势；近侧海域和远侧海域平均生物密度分别为15.36，19.64 ind./m²，平均生物量分别为1.28，3.80 g/m²；2019年近侧海域生物多样性指数较2011年有所下降，低于远侧海域；冗余分析（Redundancy Analysis，RDA）表明，盐度、水深是影响大型底栖动物的主要环境因子。围填海改变了海域的盐度、水深、沉积物等生境，加之围垦后人为频繁的扰动及陆源输入等综合因子的影响，导致大型底栖动物群落结构和多样性指数均发生变动。

Impact of Coastal Reclamation Project on Macrobenthos in Qidong Yangtze River Estuary

In order to study the impact of the coastal reclamation project on macrobenthos in Qidong Yangtze River Estuary,the macrobenthos in the outer waters of the reclamation project were investigated in spring and summer of 2019,and the community structure characteristics,diversity index and its relationship with environmental factors were analyzed.The results showed that a total of 40 species of macrobenthos were collected in 2019.Among them,19 species and 29 species of macrobenthos were collected in the near side of the embankment constructed by reclamation and the outer sea area radiated 20 km away from the coast.There were 7 and 10 dominant species in the near and far from the coast respectively.The dominant species in spring and summer were Oliva mustelina and Lumbrineris heteropoda, respectively.The dominant groups were mollusks and arthropods,and there was a trend of miniaturization and simplification.The average biological densities in the near and far from the coast were 15.36 and 19.64 ind./m²,respectively,and the average biomasses were 1.28 and 3.80 g/m²,respectively.Biodiversity index in the near-shore waters decreased from 2011 to 2019,lower than that in the far-shore waters.Redundancy analysis (RDA) indicated that salinity and depth were the major environment factors affecting the macrobenthos.Reclamation has changed the salinity,water depth,sediment and other habitats in the sea area.In addition,the frequent disturbance of people after reclamation and the influence of comprehensive factors such as land source input have led to changes in the community structure and diversity index of macrobenthos.