Suppression of herbivory by macroalgal density: a critical feedback on coral reefs?
Article first published online: 26 JAN 2011
© 2011 Blackwell Publishing Ltd/CNRS
Volume 14, Issue 3, pages 267–273, March 2011
How to Cite
Hoey, A. S. and Bellwood, D. R. (2011), Suppression of herbivory by macroalgal density: a critical feedback on coral reefs?. Ecology Letters, 14: 267–273. doi: 10.1111/j.1461-0248.2010.01581.x
- Issue published online: 20 FEB 2011
- Article first published online: 26 JAN 2011
- Editor, Tim Wootton Manuscript received 5 August 2010 First decision made 14 September 2010 Second decision made 30 November 2010 Manuscript accepted 10 December 2010
- Coral reef;
- phase shift;
- structural complexity
Ecology Letters (2011) 14: 267–273
Coral reefs globally are in decline, with some reefs undergoing phase shifts from coral-dominance to degraded states dominated by large fleshy macroalgae. These shifts have been underpinned by the overharvesting of herbivorous fishes and represent a fundamental change in the physical structure of these reefs. Although the physical structure provided by corals is regarded as a key feature that facilitates herbivore activity, the influence of the physical structure of macroalgal stands is largely unknown. Using transplanted Sargassum, the largest coral reef macroalga, we created habitat patches of predetermined macroalgal density (0.25–6.23 kg m−2). Remote video cameras revealed both grazing and browsing fishes avoided high density patches, preferring relatively open areas with low macroalgal cover. This behaviour may provide a positive feedback leading to the growth and persistence of macroalgal stands; increasing the stability of phase shifts to macroalgae.