The Distribution Pattern of Macrobenthos in Relation to Tidal Elevation and Sediment Grain Size on Three Different Tidal Flats, Gomso Bay, Korea

초록

This study was carried out to obtain some information on the intertidal zonation of macrobenthos under the conditions of different tidal elevation and sediment composition in Gomso-Bay (Panwol, Hajon, and Dongho) during 17-19, April, 1999. The 49 stations were distributed from mean high water spring (MHWS) to mean low water spring (MLWS). Surface sediment becomes progressively coarser towards the bay mouth direction so that the inner bay showed sandy silt and middle part of the bay silty-sand and slightly gravelly sandy mud. The benthic fauna comprised a total of 67 species/2.2㎡ with a mean density of 550 inds./㎡ in Panwol, 109 species/5.2㎡ with a mean density of 1,104 inds./㎡ in Hajon, and 87 species/2.4㎡ with a mean density of 815 inds./㎡ in Dongho area, respectively. As a result of r-mode analysis, two groups were established; one is high water (HW) elevation specialist, and the other is low water (LW) elevation specialist. Based on species composition, density and biomass, two stational associations were defined: (1) a group of relatively poor species richness in high tidal flat, dominated by G. chinensis, L. marilina and L. anatina. (2) the other group is that of a high species richness (low intertidal species association), dominated by H. filiformis, M. californiensis and E. longidactylus. Finally, it is suggested that the distributional patterns of the benthic macrofauna and their community structure were determined by the mean grain size and tidal elevation as main controlling factors in three different tidal flats in Gomso Bay, Korea.