International audience The Countrasts Bog (1400 m a.s.l.), located in the western part of the Mont Lozère medium mountain, has been the object of an interdisciplinary study combining multiproxy analyses which includes pollen, non-pollen palynomorphs (NPP), macrocharcoal particles, sedimentology and geochemistry, with archaeological and archaeobotanical data. The high temporal resolution of the palaeoenvironmental study, with an average resolution of 40 years between samples, allows us to trace the landscape dynamics for the last 2000 years at a micro-regional scale. During the Roman Imperial period (ca. 1st–3rd centuries AD) local agropastoral activities were moderate, whereas metallurgical activities developed in the region as attested by geochemical records. Later, during Late Antiquity and Early Medieval periods (ca. 3rd–10th centuries AD), agropastoral activities increased and human impact produced major changes in local mire dynamics with the replacement of birch wooded bogs by sedge communities. During the High Middle Ages (ca. 10th–13th centuries AD), a complex system of land uses was established, based on different activities including ore smelting, forestry and agropastoralism, attested by pollen, NPP and geochemistry data, as well as by archaeological, archaeobotanical and historical evidence. Since the Late Middle Ages (ca. 14th century AD), local metallurgical activities and forestry management decline have coincided with the expansion of grazing in uplands. This new land use favored the expansion of upland grasslands and heathlands and triggered the establishment of an open-landscape during the Early Modern Period (ca. 15th–18th centuries AD). At the end of the 19th century and the 20th century, agropastoral activities declined while reforestation was carried out.