[en] Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local populations. Meadows however undergo multiple threats linked to human activities (increased nutrient input, overfishing, invertebrate overharvesting, etc.). It is currently hard to assess how seagrass meadows could respond to anthropogenic impacts due to poor knowledge of their functional ecology. In an effort to unravel trophic interactions ruling the food webs associated to seagrass beds of the Toliara Great Reef (SW Madagascar), we studied resource segregation between two common Diogenidae hermit crabs (Dardanus scutellatus and Ciliopagurus tricolor) using stable isotope ratios. C, N and S stable isotope ratios of bulk muscle tissue were measured via CF-EA-IRMS (Elementar Vario MicroCube EA coupled to an Isoprime 100 MS).
Interspecific differences were noted in isotopic composition of carbon (δ13C = -12.22 ± 1.73 ‰ for D. scutellatus, δ13C = -14.55 ± 0.73 ‰ for C. tricolor), nitrogen (δ15N = 4.73 ± 0.53 ‰ for D. scutellatus, δ15N = 5.20 ± 0.61 ‰ for C. tricolor) and sulfur (δ34S = 14.08 ± 2.32 ‰ for D. scutellatus, δ34S = 16.73 ± 1.49 ‰ for C. tricolor), suggesting that the two species do not feed on the same items. In addition, SIBER (Stable Isotope Bayesian Ellipses in R) modeling based on C and N data clearly showed that no overlap was present in the core isotopic niches of the two species. It also indicated that the isotopic niche of D. scutellatus was greater than the one of C. tricolor, implying that the former feeds on a greater number of items than the latter. While hermit crabs are generally considered as omnivorous species, this study highlighted differences in the foraging ecology of D. scutellatus and C. tricolor. These differences could help to limit competition for food between these two species, and facilitate their coexistence in Malagasy seagrass beds.
Research Center/Unit :
MARE - Centre Interfacultaire de Recherches en Océanologie - ULiège AFFISH-RC - Applied and Fundamental FISH Research Center - ULiège
Michel, Loïc ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Océanologie
Frederich, Bruno ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Morphologie fonctionnelle et évolutive
Lavitra, Thierry; University of Toliara > Institute of Fishery and Marine Sciences (IHSM)
Lepoint, Gilles ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Océanologie
Language :
English
Title :
Use of C, N and S stable isotope ratios to highlight resource segregation among hermit crabs from tropical seagrass meadows
Publication date :
26 March 2015
Number of pages :
A0
Event name :
BASIS symposium 2015
Event organizer :
Benelux Association for Stable Isotope Scientists (BASIS)
Event place :
Utrecht, Netherlands
Event date :
26 & 27/03/2015
Audience :
International
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE] BELSPO - SPP Politique scientifique - Service Public Fédéral de Programmation Politique scientifique