Captive-breeding population supplementation and reintroduction as tools to conserve endangered Arctic fox populations in Norway : detailed proposal and progress 2001-2004

Abstract

Within its Holarctic distribution, the global population of Artic foxes (Alopex lagopus) appears to be large and stable, however the populations of Fennoscandia were already endangered in the late 1920’s. This led to their protection in Sweden, Norway and Finland in 1928, 1930 and 1940 respectively. Despite their protected status there has been little or no indication of population recovery. Based on numbers of documented reproductions we estimate that there are no more than 50 adult arctic foxes in Norway. These animals are distributed widely, thus occurring in low actual numbers with gaps between the different populations. Why arctic fox populations have failed to recover after their protection could be because of the competition from red fox (Vulpes vulpes) together with demographic collapse as a result of population decline in a fragmented landscape. Because the current population is at such a critical stage, it is important to initiate conservation actions at once. Conservation actions that can be taken include (1) Supplementary feeding to increase survival and reproduction, (2) Red fox control to reduce competition and intraguild interactions, and (3) Population supplementation / reintroduction to restore connectivity. Conservation actions (1) and (2) have been conducted in Sweden and Finland, but existing experience is not yet sufficient to conclude if these actions are effective. Conservation action (3) is therefore proposed. Although translocation of arctic foxes is generally to be preferred over the use of captive-bred animals, there are no suitable sources of wild foxes for translocation. Populations on Svalbard are not suitable due to genetic differences and the occurrence of rabies. Populations in Siberia are also not suitable due to the occurrence of rabies. Furthermore animals from captive-breeding have been used successfully in many situations for many species. The arctic fox captive-breeding programme consists of carefully adjusting and developing the method that functions best for breeding wild-caught animals in captivity. Pups born in captivity will be released with pre-release training following the experience of a successful swift fox (Vulpes velox) reintroduction project in Canada. Release sites are chosen based on the available data on arctic fox ecology, former den availability and habitat distribution. All released foxes will be post-released monitored with help of expandable radio-collars. Also dens will be monitored annually to detect changes in population development. Defining the success of the captive-breeding programme will be based on (1) Survival, (2) Pair formations, and (3) Population growth. Different expertises and institutions, from Norway, Sweden and Finland are pooled to determine which actions seem to be most successful and thus enhance our success with the reintroduction programme.