Distribuzione di marmotta alpina in valle d’Aosta e anilisi di vocazionalità. Distribution of Alpine marmot (Marmota marmota) in the Aosta valley and suitability analysis [Distribution de la marmotte alpine dans la vallée d’Aoste et analyse d’affinité].

Résumé

In the period 1988-1990 the distribution of Alpine Marmot (Marmota marmota) in the Aosta Valley was studied and the environmental characteristics of the territory inhabited by the species analyzed. This kind of analysis supplied useful information for studies on the suitability of the territory for Marmota marmota, taking the following parameters into consideration: the physionomy of the site, exposure, altitude and slope. The map of the actual distribution has been compared with that of the potential distribution. The results rising from the study are the following: -The two distributions agree quite well (out of 118.750 hectares suitable for the Marmot, 82.350 hectares, equivalent to 70%, are actually occupied by the species). The discrepancy between the two distributions may be refered to (i) non-valuation of some environnental factors such as geological structure, botanical composition of the grass-land and disturbance due to ski-lifts, mountains roads, etc. or (ii) the methods of analysis of the physiognomical composition and land-use utilized for the issue of the suitability map for the Alpine marmot.