奄美大島沿岸における干潟底生生物相

抄録

The Amami Islands are located south of Japan's main islands and their inherent fauna and flora have high species diversity. In order to augment our limited knowledge on the coastal benthic fauna of these islands, we investigated the macrobenthic fauna in four tidal flats on Amami-Oshima Island. A total of 123 species or taxa ware sampled at the four study sites, with the number of species at each site varying from 39 to 89. Species richness was highest at Tekebu-higata tidal flat (the northernmost study site) and lowest at Ichi-higata tidal flat (central Amami). Yanyu-higata in the northern part of the island, and Kunetsu-higata, the southernmost study site, had intermediate species richness. The density of benthic animals was lowest at Yanyu-higata and highest at Kunetsu-higata. The local diversity, the mean number of species at a station, did not vary markedly among the study sites (ranging from 3.35 to 4.79), whereas the species richness of tidal flats tended to differ among the study sites. This indicates that the species diversity of the tidal flats can be attributed to the diversity among stations (β diversity). The heterogeneity of benthic community is discussed in relation to tidal flat sediment condition.