The origins of the southern Scandinavian wolf Canis lupus population: potential for natural immigration in relation to dispersal distances, geography and Baltic ice
2005
Linnell, John D. C. | Brøøseth, Henrik | Solberg, Erling J. | Brainerd, Scott M.
Ever since the present phase of wolf Canis lupus population growth began in southern Scandinavia in 1983 there has been controversy surrounding their origins. Genetical analyses have clarified that the wolves originate from the Finnish-Russian populations, but the debate continues about how they came to be in southern Scandinavia, with many wolf-opponents claiming they have been released in a clandestine action. By comparing the geography of Scandinavia to known wolf dispersal behaviour our analysis focuses on whether it is possible for wolves to have recolonised southern Scandinavia without human assistance. From 298 published dispersal distances for North American wolves, 10 were over 500 km, with the longest being 886 km in a straight line. When also including data on actual distance moved, several wolves have been recorded to travel more than 4,000 km, often within only a few months. However, the published data are biased towards short-distance movements. Any wolves travelling from the Finnish-Russian border to the site of the 1983 reproduction would have to have travelled > 1,000 km, with potential routes being overland, or over the ice covered Baltic Sea during winter. From their present distribution, wolves have shown a clear ability to cross areas of sea-ice of up to 70 km. Therefore, it is possible for wolves to have colonised south Scandinavia through natural dispersal, although it requires movements at the extreme edge of what has been documented. As wolves expand in both southern Scandinavia and Finland, the distance between the populations will decrease, although contact will require passing through 500 km of the conflict-full reindeer-herding areas or crossing of the Baltic Ice.
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