Geomorphic and geographic distributions of reef-building and soft coral communities in the inshore zone of the Red Sea

Abstract

Abstract Hard and soft coral community structures were studied in eight sites in the inshore zone of the Red Sea subdivided geo-morphologically into exposed and sheltered sites and geographically into northern and southern entities. Forty-one hard coral and 13 soft coral species were recorded in the exposed sites, while 42 hard coral and 19 soft coral species were observed in the sheltered sites. The southern entity showed 46 of hard coral and species and 14 soft coral species, while the northern entity showed 43 hard coral and 22 soft coral species. Abu Dabab recorded the highest number of species (35 hard and 9 soft) at the exposed sites, Ennadi recorded the highest number of species (48 hard and 17 soft) at the sheltered sites, while Rasel Behar was the poorest site in hard species (17 species) and Sharmel Bahari in the soft species (2 species). Acropora was the most dominant hard coral genus (25.16%, 23.22%), Sinularia and Sarcophyton were the most dominant soft genera (3.11%, 3.87%) at the exposed sites and the southern entity. Stylophora dominates the hard coral cover (16.15%, 15.63%), Sarcophyton and Heterxenia were dominating the soft coral cover (8.38%, 6.98%) at the sheltered sites and northern entity. Branching hard corals and dendrite soft corals were the main in all sites and interties. Hard and soft corals were controlled by; sedimentation rates, wide range of temperature changes, direct exposure to solar radiation, neap tide stresses, wave action and differential hydrodynamic exposure. The sheltered sites showed higher evenness index and richness than the exposed sites while the exposed sites showed higher diversity. Geographically, northern entity was significantly higher in diversity, evenness indexes and species richness than the southern ones.