Développement des tourbières, changements environnementaux et action de l’Homme À l’Holocène moyen et récent en Europe occidentale : l’exemple de la prenarde-Pifoy dans le Massif Central français

Abstract

Research conducted on the origin of peatlands and mires in the eastern French Massif Central during the last years has revealed some strong links between the peatland formation dynamics and the human impact above 600 m a.s.l. However, even if the anthropogenic origin of a huge number of peatlands has been proven for those build up during the last 4,500 years, the role of human societies for the appearance of peatlands between 6,500 and 4,500 cal. yr BP (Middle to Final Neolithic Period) is still in discussion because of the lack of detailed knowledge on past agro-pastoral societies. Therefore, an interdisciplinary and multi-proxy study dealing with geomorphology, pedology, micromorphology, palynology, macrofossils, diatoms and the dating of basal peat, was conducted at the La Prenarde-Pifoy mire in the Monts du Forez mountain range. We had two main aims: at first, to reconstruct the history of agro-pastoralism and, second, to provide an accurate chronology of bioclimatical and ecological changes induced by human activities. The results show that it is impossible to sufficiently argue for an anthropogenic origin of this mire, whose lateral expansion started from about 6,204-5,895 cal. yr BP onwards. Considering the history of agro-pastoral activities during the Subboreal and Subatlantic chronozones three major phases can be reconstructed: First palynological evidence of agro-pastoral action was recorded for the time period between 5,200 and 4,800 cal. yr BP, whereas these anthropogenic signals disappear between 4,800 and 2,700 cal. yr BP, a time span during which beech-fir woods dominated the landscape. After 2,700 cal. yr BP the agro-pastoral impact started again and stayed pronounced and permanent until the 19th century AD, however with notable and changing intensity.