Community structure of Acropora corals in the Gulf of Thailand

Abstract

Scleractinian corals, genus Acropora, are the dominant group within coral assemblages in the Gulf of Thailand. The purpose of this study is to investigate the diversity, species composition, and community structure of Acropora in the Gulf of Thailand. A 30×1 m belt transect with 3 replicates were employed in each of 80 stations at 30 islands along the Gulf of Thailand. The overall diversity indices at all stations were between 0.52.0 while the evenness indices between 0.5-1.0. Commu­ nity structure of Acropora, based on coverage area, varied significantly between habitats depending on location. Based on the surveys, community structure could be di­ vided into 4 groups. The first group was the station at Klang Island on the winward­reef slope (kl12) and the station at Kra Island on the winward­reef slope (kr12), having A. aculeus as a dominant species and at station Kra Island on the leeward­reef slope (kr22), having A. nana as a dominant species. The second group was the station at Klang Island on the leeward­reef slope (kl22), which had A. formosa as the dominant species. The third group was the station at Kra Island on the leeward-reef flat (kr21), which had A. cf. copiosa, A. longicyathus, A. tenuis and A. microphthalma as the dominant species. The last group of the stations had common species and rare species of Acropora. This study showed that the current condition of Acropora in the Gulf of Thailand showed recovery after the bleaching phenomenon in 1998.