Dynamics of the colonization process in reintroduced populations of the Alpine marmot [Dynamique du processus de colonisation dans les populations réintroduites de la marmotte alpine].

Résumé

The project of marmot reintroduction in the Dolomiti Bellunesi National Park started in 2006. In May 2006 and May 2007, 80 ear-marked (by sex and family) marmots were released in two separate areas (20 ind./ year/area). In summer 2008 the populations produced 36 and 39 individuals, respectively; the animals born in the areas exceeded the number of released animals that survived. Only one pair bred successfully in the year of release; 87.5% of the surviving pairs bred the following year, including the pair breeding the previous year. We recorded the reproduction of a single female, and the acceptance of the litter by the male who later joined her. Mortality of the animals released in 2006 was 39% before the first winter and increased to 53.6% after the second summer. The first sum- mer mortality of animals released in 2007 was higher, probably because of greater predation by golden eagles. The population density increased in late summer 2008 to 13.5 and 22.2 family units/100 ha, respectively in the two areas. In 2006, when both areas were uninhabited, the mean disper- sion distance from the release site to settlement sites was greater in males than in females. Sixty-one per cent of the settlements consisted of pairs; 33%, a single male; and 6%, of a trio (marmots from different families). The single males settled more distantly than paired males. Of all the possible “same-family composed ” pairs, 77.6% occurred.