Climate impacts on deglaciation and vegetation dynamics since the Last Glacial Maximum at Moossee (Switzerland)

Abstract

Abstract. Since the Last Glacial Maximum (LGM, end ca. 19\u2009000\u2009cal\u2009BP) Central European plant communities were shaped by changing climatic and anthropogenic disturbances. Understanding long-term ecosystem reorganizations in response to past environmental changes is crucial to draw conclusions about the impact of future climate change. So far, it has been difficult to address the post-deglaciation timing and ecosystem dynamics due to a lack of well-dated and continuous sediment sequences covering the entire period after the LGM. Here, we present a new palaeoecological study with exceptional chronological time control using pollen, spores and microscopic charcoal from Moossee (Swiss Plateau, 521\u2009m\u2009a.s.l.) to reconstruct the vegetation and fire history over the last ca. 19\u2009000 years. After lake formation in response to deglaciation, five major pollen-inferred ecosystem rearrangements occurred at ca. 18\u2009800\u2009cal\u2009BP (establishment of steppe tundra), 16\u2009000\u2009cal\u2009BP (spread of shrub tundra), 14\u2009600\u2009cal\u2009BP (expansion of boreal forests), 11\u2009600\u2009cal\u2009BP (establishment of first temperate deciduous tree stands composed of e.g. Quercus, Ulmus, Alnus) and 8200\u2009cal\u2009BP (first occurence of mesophilous Fagus sylvatica trees). These vegetation shifts were released by climate changes at 19\u2009000, 16\u2009000, 14\u2009700, 11\u2009700 and 8200\u2009cal\u2009BP. Vegetation responses occurred with no apparent time lag to climate change, if the mutual chronological uncertainties are considered. This finding is in agreement with further evidence from Southern and Central Europe and might be explained with proximity to the refugia of boreal and temperate trees (