Reef classification by coral morphology predicts coral reef conservation value

Abstract

Coral reefs can be classified using triangular diagrams based on coral morphology; these taxonomy-independent classes predict several aspects of conservation value for coral reefs. Conservation classes (CC's) of 1, 2, 3 or 4 were assigned to reef sites dominated by massive and submassive corals (CC 1), foliose or branching non- Acropora corals (CC 2), Acropora corals (CC 3), or approximately equal mixes of these three end-members (CC 4). When applied to 15 Indonesian coral reefs, aggregrate conservation class, the average of the conservation class of all sites on that reef, was a reliable predictor of coral species richness, habitat complexity, and rare coral species occurrence. Aggregate conservation class predicted these aspects of conservation value more reliably than the reef condition index currently used in southeast Asia, live coral cover, or coral mortality. Definitions of reef status based solely on percentage of live coral cover should be supplemented with other indices such as conservation class that more accurately predict biodiversity value and fisheries potential. Coral morphology triangles and conservation class can be used in zoning marine protected areas and other coral reef biodiversity conservation efforts.