A lacustrine pollen retard from north Priokhot'ya: New information about late Quaternary vegetational variations in western Beringia

A pollen record from Glukhoye Lake (59 degrees 45'N 149 degrees 55'E; elevation 2.8 m a.s.l.) describes the late Quaternary vegetation history of the northern coastal region of the Okhotsk Sea. Although lacking radiocarbon dates, a tentative age scheme for the core is offered on the basis of other dated pollen stratigraphies and tephrochronology. The full-glacial pollen assemblage from Glukhoye Lake differs from other western Beringian spectra in that it has low percentages of Cyperaceae (<5%) pollen and Selaginella rupestris (<1%) spores, high percentages of Poaceae (>40%) and Asteraceae (5-20%) pollen, and low to moderate percentages of Artemisia (5-35%) pollen. This unique assemblage suggests that several types of herb-dominated communities characterized the full-glacial landscape of western Beringia. Herb tundra is replaced by shrub tundra as Betula followed by Alnus and Pinus colonized near the lake. Larix is the last major taxon of the modem vegetation to appear in the Glukhoye record. In contrast to the interior Upper Kolyma region, Pinus apparently established prior to Larix near the coast and experienced significant population fluctuations during the mid- to late Holocene. Reasons for the variability in the vegetation history between these two regions can probably be linked to differences in fall/early winter snow conditions and mean July temperatures. Today strong temperature and precipitation gradients characterize the transition from the northern Okhotsk Sea coast to the mountainous interior of the Upper Kolyma region. The Glukhoye and Upper Kolyma pollen records suggest that the Okhotsk Sea and coastal ranges have been important influences on the regional climates of southwestern Beringia throughout the Holocene.