Rights statement: https://www.cambridge.org/core/journals/environmental-conservation/article/abs/investigating-sea-urchin-densities-critical-to-macroalgal-control-on-degraded-coral-reefs/78414F16ACE03C7D518AFCA1F372D232 The final, definitive version of this article has been published in the Journal, Environmental Conservation, ?, ?, pp ?-? 2021, © 2021 Cambridge University Press.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Investigating sea urchin densities critical to macroalgal control on degraded coral reefs
AU - Dajka, J.-C.
AU - Beasley, V.
AU - Gendron, G.
AU - Graham, N.A.J.
N1 - https://www.cambridge.org/core/journals/environmental-conservation/article/abs/investigating-sea-urchin-densities-critical-to-macroalgal-control-on-degraded-coral-reefs/78414F16ACE03C7D518AFCA1F372D232 The final, definitive version of this article has been published in the Journal, Environmental Conservation, ?, ?, pp ?-? 2021, © 2021 Cambridge University Press.
PY - 2021/1/13
Y1 - 2021/1/13
N2 - Summary There is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances of Echinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m-2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions of E. calamaris in the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m-2, maximum: 0.16 urchins m-2).
AB - Summary There is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances of Echinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m-2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions of E. calamaris in the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m-2, maximum: 0.16 urchins m-2).
KW - Echinotrix calamaris
KW - functional importance
KW - habitat predictors
KW - penning
KW - Sargassum
KW - sea urchin grazing
KW - Seychelles
U2 - 10.1017/S037689292000051X
DO - 10.1017/S037689292000051X
M3 - Journal article
JO - Environmental Conservation
JF - Environmental Conservation
SN - 0376-8929
ER -