Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia

Chantale Bégin (1) , Christiane K. Schelten (2) , Maggy M. Nugues (3, 4) , Julie Hawkins (5) , Callum Roberts (6) , Isabelle M. Côté (1)

1 Department of Biological Sciences [Burnaby]
2 GEOMAR - Helmholtz Centre for Ocean Research [Kiel]
3 CRIOBE - Centre de recherches insulaires et observatoire de l'environnement
4 LabEX CORAIL - Laboratoire d'Excellence CORAIL
5 York Institute of Tropical Ecosystem Dynamics
6 Environment Department [York]

The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff , that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created), we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment) and depth. The cover of all ben-thic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.

Mots clés: Coral reefs; Sediment; Corals; Algae; Marine fish; Herbivory; Cyanobacteria; Sedimentation

Domaines: Ecologie, Environnement

Chantale Bégin, Christiane K. Schelten, Maggy M. Nugues, Julie Hawkins, Callum Roberts, et al.. Effects of Protection and Sediment Stress on Coral Reefs in Saint Lucia. PLoS ONE, 2016, 11 (2), ⟨10.1371/journal.pone.0146855⟩. ⟨hal-01281152⟩