The Lateglacial and Holocene in Central Europe: a multiproxy environmental record from the Bohemian Forest, Czech Republic
Abstrakt
The Hercynian mountain ranges were islands of mountain glaciation and alpine tundra in a Central European ice-free corridor during the Late Pleistocene. Today they are notable areas of glacial landforms, alpine-forest free areas, peatlands and woodlands.
However, our knowledge of the Lateglacial and early Holocene environmental changes in this region is limited. We present a new multi-proxy reconstruction of a mid-altitude environment in the Bohemian Forest spanning this period.
A core (5.2 m length) in the Cerne Lake cirque (1028 m a.s.l.) was subjected to lithological, geochemical, pollen and macrofossil analysis supplemented by two optically stimulated luminescence (OSL) and 10 AMS radiocarbon dates. We determined the impact of regional and supraregional climate changes on the environment.
The two most significant changes in sedimentation during the Lateglacial (17.6 and 15.8-15.5 cal. ka BP) were synchronous with regional glacial chronostratigraphy. Unlike Central European mountain ranges, in the Bohemian Forest the Younger Dryas was not coincident with glacier re-advance, but was a dry, cold episode with low lake levels, which prevailed until the early Preboreal.
Plant macrofossils indicate local establishment of Betula nana and Betula pendula/pubescens at 15.4-13.4 cal. ka BP. Comparison with Holocene records from Central Europe shows a similar immigration history of vegetation at mid and higher altitudes.
The tree line exceeded an altitude of ~1000 m a.s.l. around 10.5 cal. ka BP and coincided with rapid geochemical changes in the sediment. The 8.2 ka BP event did not have any response in the sedimentary record, but corresponded to stabilization of the Picea abies population and expansion of Fagus.
Fagus colonized the Bohemian Forest earlier than other Hercynian mid-mountains, but never predominated in the composition of the forest at higher elevations. Abies alba was the last tree species that immigrated to the study area.