Vegetation responses to climatic changes during the late glacial according to palaeobotanical data in western Lithuania : a preliminary results

The organic-rich material has been studied from the bottom part of lacustrine sediments of the Lake Kasuciai, western Lithuania. Radiocarbon dates and palaeobotanical data showed that these sediments accumulated between 13,500 and 9000 14C yr BP. The Late Glacial interstadial is defined by the dominance of Characeae and accumulation of carbonate. The Bolling is characterized by the pioneer taxa and the communities of open habitats. During the Allerod pine replaced the light demanding taxa that show development of a closer woodland habitat and dryness of climate. The short period between Bolling and Allerod with increasing representation of Betula and plants typical for the highly eroded habitats could be correlated with Older Dryas. The onset of the Younger Dryas is marked by degradation of the forest cover and expansion of heliophytic grasses. Entire vegetation cover with birch and pine forest was settled during the Preborial. Formation of calcareous sediments and appearance of thermophilous taxa confirm the climatic amelioration.