Aspects of Community Organization in Caribbean Stony Corals (Scleractinia)

Bak, Rolf

Stony corals (Scleractinia) are the ecological dominants on Caribbean coral reefs. These organisms are distributed in distinct zones over the reef profile. This pattern has been explained as the result of physiological demands but increasing emphasis is laid on ecological differences between the coral species and the predictability levels of the various habitats. However, striking anomalies are found in the occurrence of coral species and of reefs. These are in part caused by the diverse reactions of corals to the temporal and spatial heterogeneity of their environment. The continuity of the habitats is interrupted by factors such as epidemic disease, storms, outbreaks of competitions and human activities, the effect of which in turn depends on the composition of the coral community. The variations in coral response are caused by the evolution of different life histories such as displayed by Agaricia, Montastrea, Acropora and Madracis. These species differ in the way they reproduce, survive, regenerate, compete for space, their growth rates etc. Reefs and their distributive patterns are far from fully understood but the interaction of physiological requirements, life history characteristics, heterogeneity and recent history of the habitat, is of major importance in the explanation of community composition and the stage of reef development.