Evolution of vegetation landscapes since the Late Mesolithic on the French West Atlantic coast

This article presents a review of the data collected from the palynological analysis of six sites situated on the southern edge of the Armorican Massif (coastal Vendée, Western France). A multi and interdisciplinary approach, involving branches as diverse as archaeology, history, geography, geomorphology, sedimentology, climatology and the natural sciences, enabled us to gain an understanding of the evolution of vegetation and coastal ecosystems from the end of the Preboreal period to the present, and to see whether this evolution was due to the combined influence of climate and geomorphology of the environment or due to the influence of natural factors, human-induced processes or interaction between these components.Since the Preboreal, the coastal area has undergone significant geomorphological changes through a succession of marine transgressions and regressions. Coastal valleys filled up rapidly to the Atlantic and the progressive development of dune ridges led to the clogging of lagoons, resulting in the present day tidal marshes. On the first hillsides of the coastal area, and with improvement in climate conditions, a woodland environment rapidly appeared which had distinctive features related to the proximity of the ocean. These data reinforce the research already carried out on the subject and help in an understanding of the evolution of coastal and continental ecosystems. From the end of the Mesolithic period this woodland ecosystem saw clearance activities which were sometimes followed by the cultivation of such plants as cereals or walnut. The discovery of this type of occurrence is not an isolated case in continental Europe. However, the date of these occurrences raises numerous questions about the earliest stages of neolithization, about the diffusion of agricultural knowledge and the factors leading to this diffusion.