长江口盐沼湿地不同亚生境的大型底栖动物群落组成和多样性差异

Difference of macrobenthos community composition and diversity in different sub-habitats in salt marsh wetland of the Yangtze River Estuary

2015年7月—2016年6月每月在长江口盐沼湿地采集潮沟、光滩和盐沼(以海三棱藨草为主)三种亚生境的大型底栖动物样本,分析其群落组成和多样性差异。结果表明:共采集到大型底栖动物21种,隶属4门、5纲、15科,以软甲纲(7种)和多毛纲(4种)种类较多;潮沟和盐沼亚生境的优势种无差异;盐沼底栖动物物种数最高,潮沟次之,光滩物种数最低;盐沼底栖动物的密度和生物量均高于其他2种亚生境;三种亚生境的大型底栖动物密度两两间差异显著(P<0.05),而生物量无显著差异(P>0.05);盐沼底栖动物群落的Shannon多样性指数最高(1.08),光滩次之(1.03),而潮沟最低(0.63);光滩底栖动物群落的Simpson物种丰富度指数、Pielou均匀度指数值均高于潮沟和盐沼,反映光滩底栖动物群落种类密度的分布相比其他2种亚生境较为均匀;通过群落聚类和非度量多维标度分析发现,盐沼和潮沟亚生境的大型底栖动物群落结构较为相似,而与光滩差异较大,引起两者差异的主要贡献种是谭氏泥蟹、河蚬、背蚓虫等。

From July 2015 to June 2016,macrobenthos samples from three sub-habitats,including tidal creek,bare beach,and salt marsh,were collected monthly in the salt marsh wetland in the Yangtze Estuary to analyze community composition and diversity.The results showed that 21 species of macrobenthos were recorded,belonging to four phyla,five classes and 15 families.Among them,seven species were from Malacostraca and four species from Polychaeta.There was no difference in dominant species between the tidal creek and salt marsh sub-habitats.The richness of macrobenthos species was the highest in salt marsh,followed by the tidal creek and lowest in the bare beach.The density and biomass of macrobenthos in the salt marsh were higher than those in other sub-habitats.The density of macrobenthos differed significantly among the three sub-habitats(P<0.05),but without difference in biomass among sub-habitats(P>0.05).The Shannon diversity index of macrobenthic community in the salt marsh was the highest(1.08),followed by the bare beach(1.03),and the lowest in the tidal ditch(0.63).Simpson species richness index and Pielou species evenness index were higher in the bare beach than those of the tidal creek and salt marsh,indicating that the species distribution of benthic communities in the bare beach was more even than in other sub-habitats.Results from community clustering and nonmetric multidimensional scaling analysis showed that macrobenthos community structure in the salt marsh and tidal creek sub-habitats were similar,but differed from that in the bare beach.The main contributors to such differences were Ilyoplax deschampsi,Corbicula fluminea,and Notomastus latericeus.