L'anthropisation du Massif jurassien : bilan des données palynologiques

Abstract

Pollen studies carried out over the last years in the Jura Mountains allow to reconstruct the regional history of the vegetation and human impact during the last 8 millennia. Successive phases of increasing and decreasing human impact have been recognised. The first pollen evidence of human impact occurred in the Early Neolithic period (6th millennium BC). Marks of human impact appear to have been relatively weak during the Early Bronze age, and nearly absent during the Middle Bronze age. They show a clear increase at ca 1000 cal BC during the Final Bronze age. The picture is more difficult to outline for the Iron age due to problems inherent in radiocarbon dating. During the Gallo-Roman period, the increase in human impact appears to be different depending on considered altitude. The transition between Antiquity and Medieval Times coincided with a decrease in human impact, which, once again, increased during the 7th century and more particularly the 8th century. Around 1000 AD, forested areas underwent a clear retreat. After wars and epidemics which characterised the 14th century, the 15th century marked a new increase in human impact, responsible for a quasi-disappearance of forests on the Jura Mountains.