Isotopic niches of sympatric Gentoo and Chinstrap Penguins: evidence of competition for Antarctic krill?

  • Danijela Dimitrijević
  • Vitor H. Paiva
  • Jaime A. Ramos
  • José Seco
  • Filipe R. Ceia
  • Nesho Chipev
  • Tiago Valente
  • Andrés Barbosa
  • José C. Xavier
Original Paper

Abstract

As climate change, among other factors, is increasingly affecting Antarctic marine systems, competition for prey may increase between predators, particularly in the Antarctic Peninsula which has warmed more than elsewhere. Under such a context, we tested the feeding and trophic ecology of Gentoo (Pygoscelis papua) and Chinstrap (Pygoscelis antarctica) penguins breeding in sympatry at Livingston Island (Antarctic Peninsula) in a single season. We compared the diets of adults (from faecal samples, and stable isotopes in feathers and blood) and chicks (from stomach contents, and stable isotopes in down feathers, toenails and muscles of chicks that had died of unknown causes). Antarctic krill Euphausia superba dominated the diet of both species, although Gentoo Penguins fed on larger Antarctic krill than did Chinstrap Penguins. Stable isotope analyses of adult tissues revealed that both species fed at different niches in successive years, as depicted by the different levels δ13C in feathers (showing values from the previous breeding season) and whole blood (showing values from the current season). Tissues collected from chicks confirmed their diet over different time scales (i.e. days to weeks): Gentoo Penguins fed at a higher trophic level (possibly due to a more varied diet) and in different habitats than Chinstrap Penguins, providing evidence of isotopic niche separation of penguins. Our results may be relevant to the monitoring programmes of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) and suggest that adult scats, and stomach contents and tissues of recently died chicks, can be used in such programmes.

Keywords

Isotopic niche Pygoscelis antarctica Pygoscelis papua Stable isotopes Trophic interactions 

Notes

Acknowledgements

This work is part of SCAR AnT-ERA, ICED, PROPOLAR and BAS-CEPH programmes. DD was financially supported by the European Commission through the programme Erasmus Mundus Master Course—International Master in Applied Ecology (EMMC–IMAE) (FPA 532524-1-FR-2012-ERA MUNDUS-EMMC). VHP and FRC were supported by the ‘Fundação para a Ciência e a Tecnologia’ (FCT) and the European Social Fund (POPH, EU) through post-doc grants (SFRH/BPD/85024/2012 and SFRH/BPD/95372/2013, respectively). JCX was supported by the Investigator FCT programme (IF/00616/2013). This study benefitted from the strategic programme of MARE, financed by FCT (MARE - UID/MAR/04292/2013). The referees David Ainley and Grant Ballard, and Jim Reynolds provided very helpful comments and language improvements to an early draft of the manuscript for which we are much thankful.

Compliance with ethical standards

Human and animal rights

The fieldwork was conducted between December 2011 and January 2012 (inclusive) at Livingston Island, South Shetland Islands, under a research permit from the project PENGUIN of the Portuguese Polar Programme PROPOLAR. All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

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© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Life Sciences, MARE - Marine and Environmental Research CenterUniversity of CoimbraCoimbraPortugal
  2. 2.CESAM and Department of ChemistryUniversity of AveiroAveiroPortugal
  3. 3.School of BiologyUniversity of St AndrewsSt AndrewsUK
  4. 4.Central Laboratory of General EcologyBulgarian Academy of ScienceSofiaBulgaria
  5. 5.Departamento de Ecología EvolutivaMuseo Nacional de Ciencias Naturales, CSICMadridSpain
  6. 6.British Antarctic Survey, Natural Environment Research CouncilCambridgeUK

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