Dietary variation in arctic foxes (Alopex lagopus)-an analysis of stable carbon isotopes.
We used stable carbon isotopes to analyse individual variation in arctic fox diet. We extracted collagen from bones (the lower jaw), and measured stable carbon isotopes. The foxes came from three different localities: Iceland, where both microtines and reindeer are rare; west Greenland, where microtines are absent; and Sweden, where scat analyses showed the primary food to be microtine rodents and reindeer. The Icelandic samples included foxes from both coastal and inland habitats, the Swedish sample came from an inland area, and the Greenland sample from coastal sites. The spatial variation in the isotopic pattern followed a basic division between marine and terrestrial sources of protein. Arctic foxes from inland sites had δ13C values of -21.4 (Iceland) and -20.4‰ (Sweden), showing typical terrestrial values. Coastal foxes from Greenland had typical marine values of -14.9‰, whereas coastal foxes from Iceland had intermediate values of -17.7‰. However, there was individual variation within each sample, probably caused by habitat heterogeneity and territoriality among foxes. The variation on a larger scale was related to the availability of different food items. These results were in accordance with other dietary analyses based on scat analyses. This is the first time that stable isotopes have been used to reveal individual dietary patterns. Our study also indicated that isotopic values can be used on a global scale.
Department of Zoology, Stockholm University, S-106 91, Stockholm, Sweden.
Anders
A
Angerbjörn
Wildlife Management Institute, PO Box 5032, 125, Reykjavik, Iceland.
Pall
P
Hersteinsson
Department of Archaeology, Stockholm University, S-106 91, Stockholm, Sweden.
Kerstin
K
Lidén
Department of Archaeology, Simon Fraser University, V5A 1S6, Burnaby, B.C., Canada.
Erle
E
Nelson
Arctic fox; Bone; Carbon isotopes; Collagen; Diet