Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals

Kernaléguen, Laëtitia, Arnould, John P. Y., Guinet, Christophe and Cherel, Yves 2015, Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals, Journal of animal ecology, vol. 84, no. 4, pp. 1081-1091, doi: 10.1111/1365-2656.12347.

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Title Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals
Author(s) Kernaléguen, Laëtitia
Arnould, John P. Y.ORCID iD for Arnould, John P. Y.
Guinet, Christophe
Cherel, Yves
Journal name Journal of animal ecology
Volume number 84
Issue number 4
Start page 1081
End page 1091
Total pages 11
Publisher Wiley-Blackwell Publishing
Place of publication Chichester, Eng.
Publication date 2015-07
ISSN 1365-2656
Keyword(s) competition
foraging ecology
niche variation hypothesis
niche width
stable isotopes
Science & Technology
Life Sciences & Biomedicine
Environmental Sciences & Ecology
Summary The degree of individual specialization in resource use differs widely among wild populations where individuals range from fully generalized to highly specialized. This interindividual variation has profound implications in many ecological and evolutionary processes. A recent review proposed four main ecological causes of individual specialization: interspecific and intraspecific competition, ecological opportunity and predation. Using the isotopic signature of subsampled whiskers, we investigated to what degree three of these factors (interspecific and intraspecific competition and ecological opportunity) affect the population niche width and the level of individual foraging specialization in two fur seal species, the Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis), over several years. Population niche width was greater when the two seal species bred in allopatry (low interspecific competition) than in sympatry or when seals bred in high-density stabilized colonies (high intraspecific competition). In agreement with the niche variation hypothesis (NVH), higher population niche width was associated with higher interindividual niche variation. However, in contrast to the NVH, all Antarctic females increased their niche width during the interbreeding period when they had potential access to a wider diversity of foraging grounds and associated prey (high ecological opportunities), suggesting they all dispersed to a similar productive area. The degree of individual specialization varied among populations and within the annual cycle. Highest levels of interindividual variation were found in a context of lower interspecific or higher intraspecific competition. Contrasted results were found concerning the effect of ecological opportunity. Depending on seal species, females exhibited either a greater or lower degree of individual specialization during the interbreeding period, reflecting species-specific biological constraints during that period. These results suggest a significant impact of ecological interactions on the population niche width and degree of individual specialization. Such variation at the individual level may be an important factor in the species plasticity with significant consequences on how it may respond to environmental variability.
Language eng
DOI 10.1111/1365-2656.12347
Field of Research 060201 Behavioural Ecology
060205 Marine and Estuarine Ecology (incl Marine Ichthyology)
060207 Population Ecology
Socio Economic Objective 970106 Expanding Knowledge in the Biological Sciences
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2015, Wiley-Blackwell Publishing
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