长江口不同盐沼生境中大型底栖动物的分布特征

Distribution characteristics of the macrobenthos in different vegetation salt marshes of the Changjiang River estuary

本文对2020年长江口盐沼植被、沉积物和大型底栖动物的调查结果进行统计分析,研究长江口崇明北滩、崇明东滩、横沙边滩、南汇边滩、奉贤和金山边滩的芦苇、互花米草、海三棱藨草等7种植被盐沼中大型底栖动物群落分布特征。结果表明:(1)2020年长江口盐沼共鉴定出大型底栖动物39种,不同植被生境中大型底栖动物种类差异明显。其中,海三棱藨草内的大型底栖动物种类数最多。(2)与其他盐沼植被相比,海三棱藨草生境具有较高的大型底栖动物丰富度,海三棱藨草盐沼生态系统中大型底栖动物的生物量和密度均为最大,分别为933 ind./m^(2)和59.96 g/m^(2)。(3)大型底栖动物多样性指数、均匀度指数和丰富度指数分别为1.39、0.61、0.55。总体而言,糙叶薹草、互花米草和芦苇盐沼中的大型底栖动物多样性高于其他盐沼;在高、中位盐沼中,不同盐沼植被大型底栖动物多样性差异不大,但在低位盐沼中海三棱藨草中大型底栖动物生物多样性明显高于互花米草。(4)大型底栖动物分布与沉积物粒度、总氮、总磷具有相关性。甲壳类和多毛类动物主要分布在中值粒径为4.5~5.5(φ)和6~7(φ)之间;多毛类主要分布在总氮和总磷含量水平较高的区域,而软体动物则主要分布在总氮和总磷含量较低的区域。

Based on the quantitative data of vegetation,sediment,and macrobenthos in the salt marshs of the Changjiang River Estuary in 2020,the distribution characteristics of macrobenthos communities in seven vegetation types of salt marshes,including Phragmites australias,Spartina alterniflora,and Scirpus triquetris were studied.The results showed that(1)A total of 39 species of macrobenthos were identified in the salt marshes of the Changjiang Estuary in 2020.Moreover,differences in the macrobenthos species in the different vegetation habitats were signifi-cant.The number of macrobenthos species in the Scirpus mariqueter salt marsh was the highest.(2)Compared with other salt marshes,the diversity of macrobenthos in the Scirpus mariqueter salt marsh was higher;moreover,the bio-mass and density of the macrobenthos in the Scirpus mariqueter salt marsh were the highest,933 ind./m^(2) and 59.96 g/m^(2),respectively.(3)Furthermore,the diversity index,evenness index,and richness index of macrobenthos were 1.39,0.61,and 0.55,respectively.Moreover,the macrobenthos diversity in the Carex scabrifolia,Spartina al-terniflora,and Phragmites australias salt marshes was higher than that in other salt marshes.In the high and median elevation salt marshes,no significant difference was observed in macrobenthos biodiversity among different vegeta-tion salt marsh;however,the macrobenthos biodiversity of Scirpus mariqueter salt marsh was significantly higher than that of Spartina alterniflora salt marsh in the low elevation salt marsh.(4)The macrobenthos distribution was corre-lated with the sediment particle size,total nitrogen,and total phosphorus.Crustacea and Polychaeta were mainly dis-tributed between median particle sizes of 4.5~5.5(φ)and 6~7(φ),respectively.Polychaeta was mainly distributed in areas with high total nitrogen and total phosphorus contents,and mollusks were mainly distributed in areas with lower contents.This study could provide a scientific basis for the restoration,protection,and management of coastal salt marsh wetlands and have important theoretical and practical significance.