Abstract


CORAL REEF RECOVERY AND REORGANISATION IN THE INDIAN OCEAN

Coral bleaching in 1998 was particularly severe in the Indian Ocean, where up to 90% coral cover was lost in some locations. I will talk about the unfolding dynamics from this disturbance event on Seychelles reefs, from both an ecological and geological perspective, and the changing structure of these reefs. Around half of the reefs in the inner Seychelles recovered towards pre-disturbance live coral states by 2014, while the other half underwent regime shifts to fleshy macroalgae. Functional diversity of associated reef fish communities shifted substantially following bleaching, returning towards pre-disturbance structure on recovering reefs, while becoming progressively altered on regime shifting reefs. These changes are also reflected in food chain lengths of reef meso-predators, feeding on shorter, simplified chains on degraded reefs. Recovery was favoured when reefs were structurally complex and in deeper water, when density of juvenile corals and herbivorous fishes was relatively high and when nutrient loads were low. From a geological perspective, fewer reefs regained a positive carbonate budget following the bleaching event, with presence of macroalgae, massive corals, wave exposure and parrotfish biomass influencing carbonate budget outcomes. Worryingly, by 2014, few reefs had regained the attributes that promoted recovery from the 1998 event, rendering them vulnerable to future disturbance. Marine reserves had little bearing on reef trajectory, and the influence of this management system on the fish community appears to be changing.

Authors

Graham, N. A., Lancaster University, United Kingdom, nick.graham@lancaster.ac.uk

Jennings, S., University of East Anglia, United Kingdom

MacNeil, M. A., Australian Institute of Marine Science, Australia

Mouillot, D., Universite de Montpellier, France

Wilson, S. K., Department of Parks and Wildlife, Australia

Januchowski-Hartley, F. A., IRD, France

Nash, K. L., University of Tasmania, Australia

Hempson, T. N., James Cook University, Australia

Perry, C. T., University of Exeter, United Kingdom

Details

Oral presentation

Session #:17
Date: 06/23/2016
Time: 14:45
Location: 313 A

Presentation is given by student: No