Krimou S. auteur aut IRD Gairin E. auteur aut IRD Gautrand L. auteur aut IRD Sowinski J. auteur aut IRD Trotier M. auteur aut IRD Minier L. auteur aut IRD Bischoff H. auteur aut IRD Sturny V. auteur aut IRD Maueau T. auteur aut IRD Waqalevu V. auteur aut IRD Bulleri F. auteur aut IRD Raick X. auteur aut IRD Bertucci Frédéric auteur aut IRD Lecchini David auteur aut IRD text journalArticle eng text/pdf born digital access Macroalgae are becoming dominant on coral reefs worldwide, replacing corals as key habitat formers. Incrementing consumption rates by herbivores, such as sea urchins, has been identified as a viable strategy for promoting coral recovery. By means of a 28-day experiment, we assessed the grazing effects of the sea urchins, Tripneustes gratilla and Diadema setosum, on the macroalgal assemblages of shallow reefs at Bora-Bora (French Polynesia). In particular, each urchin species was either absent or maintained, using cages (n = 10), at a density of 5 individuals/m2. T. gratilla exerted stronger negative effects than D. setosum on all the examined macroalgae (i.e., Turbinaria ornata, Padina boryana, Halimeda spp, Dictyota spp). In addition, the grazing effects by T. gratilla on macroalgae emerged shortly after the start of the experiment, more rapidly than those of D. setosum. Despite an apparent lower food preference for T. ornata in D.setosum, all macroalgae were consumed by both species and the composition of the macroalgal assemblages (i.e., the proportion of each species) did not change after 28 days. Overall, our study suggests that herbivorous sea urchins, when at relatively high densities, could contribute to sustaining coral-dominance on coral reefs by keeping macroalgae under control. specialized POLYNESIE FRANCAISE BORA BORA PACIFIQUE 035SUBVEG 074MICFLO02 036MILMAR 564 151900 [7 ] 2023 0022-0981 https://www.documentation.ird.fr/hor/fdi:010091851 10.1016/j.jembe.2023.151900 0022-0981 [F B010091851] https://www.documentation.ird.fr/hor/fdi:010091851 https://www.documentation.ird.fr/intranet/publi/2025-01/010091851.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2024-10-22 2025-02-24 fdi:010091851 fre