The Decline of the Arctic Fox in Scandinavia
The arctic fox has lived in the Scandinavian countries of Norway, Finland, and Sweden since the last Ice Age, which ended more than10,000 years ago. Today, however, the arctic fox in Scandinavia is in severe trouble. Despite intense conservation efforts, its numbers have been radically declining. Why this most resourceful of species has been unable to rebound since hunting it was prohibited is not altogether clear.
One possibility is that the animals have gone through what biologists refer to as a population bottleneck. Such bottlenecks occur when the number of animals in a given population is reduced to the point where inbreeding enables the enhanced proliferation of genes that may be detrimental to a species’ overall fitness (ability to survive). A related hypothesis is that the arctic foxes had lost their genetic advantage owing to the spread of genes from selectively bred foxes that escaped from farms. Captive-raised foxes are known to have escaped, and recent genetic studies from Norway have shown that such interbreeding between farm-bred foxes and foxes in the wild has indeed taken place. While these results are being viewed as potential future trouble, there is still no indication that they explain past difficulties. The number of crossover genes detected in the Norwegian study was small, suggesting that mixing between wild and escaped foxes is a recent occurrence.
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