灵昆岛潮间带大型底栖动物群落结构与生态位分析

2003年11月至2004年8月,在温州湾的灵昆岛东滩进行了大型底栖动物采样调查。共发现大型底栖动物33种,隶属7门8纲21科。主要为软体动物、节肢动物和环节动物多毛类,其中高潮带25种,中潮带30种,低潮带14种。通过对不同季节不同潮带的大型底栖动物密度数据进行成对t检验分析,结果认为各潮带的大型底栖动物密度分布有明显差异,而大型底栖动物密度的季节变化不明显。对定量取样中获得的21个物种以Shannon-W iener指数为基础进行了生态位宽度测定,以P ianka重叠指数为基础进行了生态位重叠值分析,结果表明日本沙蚕(N ereis jap on ica)、纽虫和线虫的生态位较宽,均为2.80以上,它们之间的生态重叠值也较高,均为0.90以上。以密度数据四次开方为基础,利用欧氏距离进行群落物种的系统聚类分析,结果表明21个物种可以分为三大类,即潮间带广布种、中高潮带常见种、狭布种和偶见种,通过非度量多维标度排序分析也支持以上结果。3类物种的生态位重叠值均有不同的表现,与物种的分布与数量相关。研究表明,物种生态宽度、物种之间的生态位重叠值与物种的分布与数量密切相关,反映了大型底栖动物群落中各物种对生境资源的利用能力的强弱。

The structure of the macrobenthic community and niche analysis at a tidal flat of Linkun Island

During Nov.,2003 to Aug.,2004,the authors studied the macrobenthic community of the east tidal flat of Lingkun Island,Wenzhou Bay.We found a total of 33 species in the investigation,belonging to 21 families,8 classes and 7 phyla,most of them being arthropods and mollusks.The numbers of species found on the high tidal flat,middle tidal flat and low tidal flat were 25,30 and 14.Through paired t-tests we found that the main factor of impact on the macrobenthos density distribution is the factor of tidal flat elevation;the influence of seasonal variation was not evident.Using the Shannon-Wiener's niche breadth index and the Pianka's niche overlaps index,we found that the Nereis japonica,nemerteans and eelworms had broad niche breadths(above 2.80);the niche overlaps among them was high(above 0.90) in the quantitative analysis on the 21 species present in the quantitative sample analysis.Based on the fourth power of macrobenthos density,using the Hierarchical Cluster of between-groups linkage method and the Non-matric Multidimentional Scaling method, the 21 species have been classified into three groups: the widespread species,the common species on the high and middle tidal flat,and the rare species.The species of different groups have different niche overlap characters;the niche overlaps relate to the distribution and density of the species.The results reveal that the niche breadth and the niche overlap reflects the species distribution,the quantity characters and the species ability to utilize the environmental resource.