The study has been performed considering the initial place of marmot releasing (Site 1, Gandoulet) as the reference point. Compass bearing (angle of the topographic direction between the reference point and a given site) is calculated for each point and the information is reported on a graphe in polar coordinates. From the reference point, two privileged directions of colonization are conspicuous : one towards south-west, the other towards north-east.
The analysis by steps of 10 years indicates that the colonization axes have evolved during time: first mainly towards South-West and North-West, and then towards South and West and, at least, towards East and North. Currently, colonization is multidirectionnal.
