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dc.contributor.authorTarroux, Arnaud
dc.contributor.authorLydersen, Christian
dc.contributor.authorTrathan, Philip N.
dc.contributor.authorKovacs, Kit M.
dc.coverage.spatialPowell Island, South Orkney Islandsnb_NO
dc.description.abstractPenguins are a monophyletic group in which many species are found breeding sympatrically, raising questions regarding how these species coexist successfully. Here, the isotopic niche of three sympatric pygoscelid penguin species was investigated at Powell Island, South Orkney Islands, during two breeding seasons (austral summers 2013–2014 and 2015–2016). Measurements of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios were obtained from blood (adults) or feather (chicks) samples collected from Adélie Pygoscelis adeliae, chinstrap P. antarctica, and gentoo P. papua penguins. Isotopic niche regions (a proxy for the realized trophic niches) were computed to provide estimates of the trophic niche width of the studied species during the breeding season. The isotopic niche regions of adults of all three species were similar, but gentoo chicks had noticeably wider isotopic niches than the chicks of the other two species. Moderate to strong overlap in isotopic niche among species was found during each breeding season and for both age groups, suggesting that the potential for competition for shared food sources was similar during the two study years, although the actual level of competition could not be determined owing to the lack of data on resource abundance. Clear interannual shifts in isotopic niche were seen in all three species, though of lower amplitude for adult chinstrap penguins. These shifts were due to variation in carbon, but not nitrogen, isotopic ratios, which could indicate either a change in isotopic signature of their prey or a switch to an alternative food web. The main conclusions of this study are that (1) there is a partial overlap in the isotopic niches of these three congeneric species and that (2) they responded similarly to changes that likely occurred at the base of their food chain between the 2 years of the study.nb_NO
dc.rightsNavngivelse 4.0 Internasjonal*
dc.subjectAntarctic krillnb_NO
dc.subjectEuphausia superbanb_NO
dc.subjectinterspecific competitionnb_NO
dc.subjectisotopic nichenb_NO
dc.subjectpygoscelid penguinnb_NO
dc.subjectstable isotopesnb_NO
dc.titleTemporal variation in trophic relationships among three congeneric penguin species breeding in sympatrynb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.subject.nsiVDP::Zoologiske og botaniske fag: 480nb_NO
dc.subject.nsiVDP::Zoology and botany: 480nb_NO
dc.source.journalEcology and Evolutionnb_NO
dc.relation.projectNorges forskningsråd: 222798nb_NO

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