The alpine marmot (Marmota marmota) in the Gran Paradiso National Park [La marmotte alpine (Marmota marmota) du Parc National du Gran paradiso].

Résumé

The distribution of Alpine marmot (Marmota marmota) in the Gran Paradiso National Park has been valuated with the help of people employed for the surveillance of the Park. In order to achieve this, observation cards accompanied by I.G.M. maps, scale l : 25.000, were supplied in which the rangers notes down the location of used burrows and, during the spring time, the position and the nunber of winter burrows. On the basis of these observations a Marmot distribution map (with a grid of 25 hectares, side 500) has been produced. The survey regarding the number of winter burrows has made it possible to evaluate the certain minimum density of Alpine marmot in the Park. The number of winter burrows has been multiplied by the average number of marmot per winter burrows (n=4) and by the average number of marmot per family (6.l). In the first case 4492 marmots and in the second 6850 marmots. Considering that the suitable area for Marmot in the Park is about 36.000 hectares (excluding forest areas, rocks areas and glaciers) we get a certain minimum density of12-19 marmots per100 hectares. The real inhabited area is about 18.800 hectares and the real density is of 23-36 marmots per100 hectares.