Possible impact of snow depth and ungulate carcasses on red fox (Vulpes vulpes) populations in Norway, 1897–1976

Authors

  • V. Selås,

    1. Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
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  • J. O. Vik

    1. Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
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    • *Current address: Division of Zoology, Department of Biology, University of Oslo, PO Box 1050 Blindern, N-0316 Oslo, Norway.


Correspondence
Vidar Selås, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, N-1432 Ås, Norway.
Email: vidar.selas@umb.no

Abstract

During the 1900s, the number of red foxes Vulpes vulpes increased in northern Europe. At higher altitudes and latitudes, red fox populations are likely to be limited by thick snow cover, which makes small rodents less available. The negative effects of snow could, however, be compensated for by high ungulate numbers, because of increased availability of carcasses in snow-rich winters. In the period 1897–1932, the number of foxes (mainly red foxes) killed was negatively related to snow depth indices in 13 of the 17 Norwegian counties. During 1947–1976, after a strong increase in ungulate and red fox numbers, the number of red foxes killed was negatively related to snow in only one county. The counties where ungulate density increased the most also had higher increases in the number of red fox bounties paid. The absence of large predators may at least partly be responsible for the strong increase in red fox populations, because eradication of large predators such as wolf Canis lupus in the late 1800s and early 1900s probably was a necessary condition for the strong increase in ungulate numbers, especially roe deer Capreolus capreolus.

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