The Marine Side of a Terrestrial Carnivore: Intra-Population Variation in Use of Allochthonous Resources by Arctic Foxes
Arnaud Tarroux
Joël Bêty
Gilles Gauthier
Dominique Berteaux
10.1371/journal.pone.0042427
https://plos.figshare.com/articles/dataset/The_Marine_Side_of_a_Terrestrial_Carnivore_Intra_Population_Variation_in_Use_of_Allochthonous_Resources_by_Arctic_Foxes/122280
<div><p>Inter-individual variation in diet within generalist animal populations is thought to be a widespread phenomenon but its potential causes are poorly known. Inter-individual variation can be amplified by the availability and use of allochthonous resources, i.e., resources coming from spatially distinct ecosystems. Using a wild population of arctic fox as a study model, we tested hypotheses that could explain variation in both population and individual isotopic niches, used here as proxy for the trophic niche. The arctic fox is an opportunistic forager, dwelling in terrestrial and marine environments characterized by strong spatial (arctic-nesting birds) and temporal (cyclic lemmings) fluctuations in resource abundance. First, we tested the hypothesis that generalist foraging habits, in association with temporal variation in prey accessibility, should induce temporal changes in isotopic niche width and diet. Second, we investigated whether within-population variation in the isotopic niche could be explained by individual characteristics (sex and breeding status) and environmental factors (spatiotemporal variation in prey availability). We addressed these questions using isotopic analysis and Bayesian mixing models in conjunction with linear mixed-effects models. We found that: <em>i</em>) arctic fox populations can simultaneously undergo short-term (i.e., within a few months) reduction in both isotopic niche width and inter-individual variability in isotopic ratios, <em>ii</em>) individual isotopic ratios were higher and more representative of a marine-based diet for non-breeding than breeding foxes early in spring, and <em>iii</em>) lemming population cycles did not appear to directly influence the diet of individual foxes after taking their breeding status into account. However, lemming abundance was correlated to proportion of breeding foxes, and could thus indirectly affect the diet at the population scale.</p> </div>
2012-08-03 00:38:00
ecology
Community Ecology
Energy flow
Food web structure
Niche construction
Trophic interactions
Behavioral ecology
Population ecology
Terrestrial ecology
Population biology
Population Dynamics
Predator-prey dynamics
Zoology
Mammalogy
terrestrial
intra-population
allochthonous
resources
arctic
foxes