THE LATEGLACIAL AND POSTGLACIAL VEGETATION HISTORY OF THE NORTHWESTERN LIMITS OF BERINGIA, BASED ON POLLEN, STOMATE AND TREE STUMP EVIDENCE

Abstract

In order to reconstruct the Late- and Postglacial vegetation history of the northwestern edge of Beringia, a sediment core was collected from a lake north of the present treeline along the lower Lena River of northeastern Siberia, and analysed for fossil pollen and stomates. In addition, fossil tree stumps were collected in the vicinity of the lake. Eight radiocarbon dates indicate that the lake sediment record spans at least the past 12,300yrBP. The early vegetation at this site was dominated by herb and shrub tundra. Possible evidence of Younger Dryas cooling, consisting of a decrease in shrub birch and increases in grass and herbaceous plants, occurs between 11,000 and 10,000yr BP. Forests, dominated by Larix dahurica and including Picea obovata, extended northward to the site between 8500 and 3500yr BP. There is an agreement between the pollen, stomate and tree stump evidence for this advance. The modern vegetation of shrub tundra was established after 3500yr BP.