Benthic Ecology of the Polychaetous Annelids in Kwang-Yang Bay, Korea: 1. The Relationship of the Community Structure to Environmental Factors

초록

The purpose of this study is to examine relationships between polychaete species diversity and selected environmental factors in Kwangyang Bay, Korea. Sampling of macrobenthos and environmental variables were carried out at 30 stations in July 1992 and February 1993. Polychaetes were composed of 146 species with a mean density of 1,186 ind./m^2 during the summer 1992 and 149 species with a mean density of 1,274 ind./m^2 during the winter 1993. Significant changes in number of species, species richness and density of the polychaete communities were found according to sorting value and salinity of the bottom water. As a result of principal component analysis, four major polychaete assemblages are identified in the Kwangyang Bay; a delta-sand assemblage, inner bay assemblage, adjacent channel assemblage and channel assemblage. The delta-sand and inner bay assemblages are characterized by low species richness and low densities, while channel assemblage present the highest species richness and density. The stepwise discriminant analysis showed that there were certain correlations between these assemblage and following environmental variables: silt content, sorting value, bottom temperature, depth, bottom salinity, and gravel content. From the results of canonical discriminant analysis, in particular, the difference in species composition appeared to correspond most clearly to sorting value and silt content of the sediments.