The Ferlo territory is increasingly "occupied", humanly, environmentally and institutionally. A mapping based on the perceptions of local stakeholders (ZADA in French, PBRM or Perception-Based Regional Mapping) was carried out to identify the factors that, from the point of view of these stakeholders, structure the spatial organization of this territory and its surroundings: uses, practices, localisms or any other factor identified. By GIS-merging together all the maps obtained, each corresponding to an interview, we obtain a spatialized database on the determinants structuring this territory. Although the structural, ecological and socio-historical elements remain and even tend towards the specialization of territories into production 'countries', the short 2-months period herds graze in the Ferlo and the generalized use of supplementation during the pastoral lean season suggests a reorientation of these herds towards the south. It induces areas of possible tension where the north-south axis of transhumance and the West-East axis of agricultural colonization intersect. This experimental method allows us to reflect on the role of environmental observatories and the Ferlo in particular.