Comparative Effects of Different Disturbances in Coral Reef Habitats in Moorea, French Polynesia

Abstract EN

Degradation and loss of critical coastal habitats has significant ramifications for marine fisheries, such that knowledge of changes in habitat quality and quantity are fundamental to effective ecosystem management.

This study explores changes in the structure of coral reef habitats, specifically changes in coral cover and composition, in Moorea, French Polynesia, to assess the independent and combined effects of different disturbances since 1979.

During this period, reefs on the north coast have been subject to coral bleaching, severe tropical storms, as well as outbreaks of Acanthaster.

Coral cover varied significantly among years, showing marked declines during some, but not all, disturbances.

The greatest rates of coral loss coincided with outbreaks of A.

planci.

Moreover, successive disturbances have had differential effects among coral genera, leading to strong directional shifts in coral composition.

Acropora is declining in abundance and coral assemblages are becoming increasingly dominated by Pocillopora and Porites.

Observed changes in the cover and composition of corals are likely to have further significant impacts on the reef fish assemblages.

Given that significant disturbances have been mostly associated with outbreaks of A.

planci, rather than climate change, effective ecosystem management may reduce and/or delay impending effects of climate change.