Biodiversity of scleractinian corals in the reefs of Qeshm and Larak Islands of the Persian Gulf, in association with environmental variables

Abstract

Diversity of hard corals is investigated on the reefs of two Iranian islands, Qeshm and Larak, located in the Persian Gulf. The corals were sampled and photographed and their percentage cover was estimated by diving in June 2008 and February 2009. Thirty-eight coral species belonging to 20 genera and nine families were identified, of which three species are new records from the Gulf. Coral diversity was higher in Larak Island, and in total, Acroporidae and Faviidae were the most diverse coral families. Acropora (83%) had the highest percentage cover in Larak Island, while the maximum percentage cover in Qeshm Island was for Porites (52.96%). Canonical correspondence analysis distinctly plotted the study sites against environmental variables. Salinity and pH were the most effective variables on the coral diversity, and had positive correlations with the frequency of several species including Pocillopora damicornis, Platygyra acuta and Acanthastrea maxima, while they had negative correlation with another group of other corals, including Plesiastrea devantieri, Acropora downingi and Psammocora digitata (P < 0.01). Water clarity had positive correlations with some coral species, including Cyphastrea serailia and Coscinaraeamonile, and negative correlations with other species such as Leptastrea transversa and Acropora arabensis. Diversity of a number of corals mainly Porites lutea and Cyphastrea chalcidicum had high affinity with the water temperature. The results of this study supported the existence of diversified coral communities in Iranian islands, while showing that their spatial and temporal distribution can be affected by environmental variables.