江苏中部海岸互花米草盐沼底栖动物的组成特征

Composition of the benthic macrofauna in the Spartina alterniflorea salt-marshes in the Wanggang area,central Jiangsu coast,eastern China

在江苏海岸,人工引种的互花米草正在成为盐沼植被的优势物种.为了了解互花米草引种对环境与生态的影响,调查了互花米草盐沼底栖动物的组成特征.在王港地区互花米草滩由西向东设置的4个站位上,进行了夏初和秋末两个时期的野外调查,采集了40个样方内可见的全部动物样本,记录了环境特征.在实验室鉴定了样本的种属,测量了动物介壳的长度.对所获数据的统计分析结果显示,本区互花米草盐沼中有7种大型底栖动物,夏初和秋末生物种类相同,但秋末生物量明显高于夏初.在代表性种属中,珠带拟蟹守螺(Cerithidea cingulata)的壳长从初夏到秋末有明显增大,而秋末粗糙滨螺(Littorna scabra)和赤豆螺(Bithynia fuchsiana)比初夏小且少.在互花米草盐沼的不同部位,腹足类物种分布有显著差异.现场观察数据显示,一些当地盐沼动物已经适应于在人工引种的互花米草盐沼中生存.

On the Jiangsu coast,eastern China,Spartina alterniflora,which was artificially introduced into the region,is becoming a dominant plant species in the inter-tidal salt marshes.For a better understanding of the environmental and ecological impact of the colonization of Spartina alterniflorea,the benthic macrofauna of the Spartina marshes of the Wanggang area,central Jiangsu coast,is investigated.At four stations located along a shore-normal profile across the Spartina salt-marsh,field work was carried out in May and November,2006,to collect benthic macrofauna samples.At each of the stations,and for each of the seasons,5 sampling areas（1m×1m in size） were established and all of the animal specimen that were present on the bed were collected,together with records of the associated environmental characteristics.In laboratory,the length of the shells was measured,and the species of the specimen was identified.Statistical analysis of the data obtained shows that there are 7 dominant macrofauna species,and the species compositions at the various stations in early summer is the same as those in late autumn.The size and number of Cerithidea cingulata in late autumn are larger than those in early summer,whilst the size and number of Littorna scabra and Bithynia fuchsiana show a different pattern,i.e.,they are relatively large in early summer.The biomass（represented by the number of individuals） varies significantly in different parts of the salt-marsh.The in situ observations indicate that some of the native species have adapted to the new ecological environment created by the artificially introduced cordgrass Spartina alterniflorea.