Quelques considérations sur l'expansion de la population de marmottes dans la vallée de Brembana, haute vallée des Alpes orobiennes. Some considerations on marmot population expansion in Brembana Valley (Orobie Alps).

Résumé

During the years 1985-1987 and 1992 in the same geographical area we carried out two research campaigns whose data have been collected following the identical methodology. Afterwards collecting data concerning population distribution and density have been processed with regard to four ecological parameters: altitude, exposure, slope, duration of sunlight exposition. The comparison between the two periods considered permits to focus on some aspects concerning the population evolutive trend. It is a young fully expanding population whose environmental choices have change as a result of the different available habitats. The distribution trend, related to the four parameters considered, has showed an extension in variation intervals, increasing density has caused an environment colonization in adverse condition as far as the exposure and the slope.