Title

Temporal variability in arctic fox diet as reflected in stable-carbon isotopes; the importance of sea ice

Authors

Authors

J. D. Roth

Abbreviated Journal Title

Oecologia

Keywords

carbon 13; Alopex lagopus; scavenging; stable isotope ratios; TERRESTRIAL FOOD WEBS; ALOPEX-LAGOPUS; POLAR BEARS; GOOSE COLONY; BERING; SEA; HUDSON-BAY; RED FOX; MARINE; POPULATION; DYNAMICS; Ecology

Abstract

Consumption of marine foods by terrestrial predators can lead to increased predator densities, potentially impacting their terrestrial resources. For arctic foxes (Alopex lagopus), access to such marine foods in winter depends on sea ice, which is threatened by global climate change. To quantify the importance of marine foods (seal carrion and seal pups) and document temporal variation in arctic fox diet I measured the ratios of the stable isotopes of carbon (C-13/C-12) in hair of arctic foxes near Cape Churchill, Manitoba, from 1994 to 1997. These hair samples were compared to the stable carbon isotope ratios of several prey species. Isotopic differences between seasonally dimorphic pelage types indicated a diet with a greater marine content in winter when sea ice provided access to seal carrion. Annual variation in arctic fox diet in both summer and winter was correlated with lemming abundance. Marine food sources became much more important in winters with low lemming populations, accounting for nearly half of the winter protein intake following a lemming decline. Potential alternative summer foods with isotopic signatures differing from lemmings included goose eggs and caribou, but these were unavailable in winter. Reliance on marine food sources in winter during periods of low lemming density demonstrates the importance of the sea ice as a potential habitat for this arctic fox population and suggests that a continued decline in sea ice extent will disrupt an important link between the marine and terrestrial ecosystems.

Journal Title

Oecologia

Volume

133

Issue/Number

1

Publication Date

1-1-2002

Document Type

Article

Language

English

First Page

70

Last Page

77

WOS Identifier

WOS:000178224300010

ISSN

0029-8549

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