Evolution of vegetation in the eastern part of Khanka Plain (south of the Russian Far East) in the Late Pleistocene cryochron (MIS 2) and the Early Holocene

Abstract

Reconstructions of changes in vegetation, climate and sedimentation in the eastern part of the Khanka Plain for the last 22 000 cal BP were made from results of palynological analyses. A new evidence of considerable changes in the vegetation structure were provided by the palynological studies supplemented with radiocarbon dates on wood fragments and plant detritus recovered from alluvial, lacustrine and mires sediments. It has been found that at the glacial stage MIS 2, open birch forests with larch and spruce, alternating with Sphagnum mires with shrub birch was dominated the Khanka Plain. Later, at the interstadial, formations typical of southern boreal dark coniferous (needle-leaved) taiga became widely spread. The Early Holocene was marked by wide expansion of broadleaf trees (and first of all, elm and Mongolian oak) in the Khanka Plain ecosystems. Mixed forests with Korean pine became widely spread in the mountains surrounding the lowland. Mires, patches of dark coniferous forests, and open forests of larch persisted on the plains adjoining the lake and on swampy valley floors.