Middle to Late Holocene vegetation history of the Upper Engadine (Swiss Alps): the role of man and fire

摘要: To reconstruct the vegetation and fire history of Upper Engadine, two continuous sediment cores from Lej da Champfer San Murezzan (Upper Engadine Valley, southeastern Switzerland) were analysed for pollen, plant macrofossils, charcoal kerogen. The chronologies are based on 38 radiocarbon dates. Pollen macrofossil data suggest a rapid afforestation with Betula, Pinus sylvestris, cembra, Larix decidua after retreat glaciers lake catchments 11,000 cal years ago. This type persisted until ca. 7300 b.p. (5350 b.c.) when Picea replaced cembra. indicative human impact suggests that in this high-mountain region central Alps strong anthropogenic activities began during Early Bronze Age (3900 b.p., 1950 b.c.). Local settlements led to vegetational changes, promoting expansion Alnus viridis. In case Larix, continuing land use especially grazing formation meadows. viridis was directly induced by fire, as evidenced time-series analysis. Subsequently, process forest conversion into open landscapes continued millennia reached its maximum at end Middle Ages around 500 (a.d. 1450).