The structure of the macrobenthic community and niche analysis at a tidal flat of Linkun Island
灵昆岛潮间带大型底栖动物群落结构与生态位分析

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.