Not herbs and forbs alone: pollen‐based evidence for the presence of boreal trees and shrubs in Cis‐Baikal (Eastern Siberia) derived from the Last Glacial Maximum sediment of Lake Ochaul

Abstract

A new accerator mass spectrometry (AMS)‐dated sedimentary record from Lake Ochaul (54°14′N, 106°28′E; 641 m a.s.l.) in Eastern Siberia covers the interval from ca. 27 850 to 20 400 cal a bp at ca. 180‐year resolution and contributes to a better understanding of the complex spatial vegetation pattern during the Last Glacial Maximum (LGM). Non‐arboreal pollen taxa are abundant in the pollen assemblages (mean value ca. 92.6%), but boreal trees are represented by all major taxa that grow in the lake catchment today, including Betula sect. Albae (0.6–4.8%), Picea (0.6–2.8%), Pinus sibirica ( Haploxylon type) (up to 1.5%), Pinus sylvestris ( Diploxylon type) (up to 2%), Larix (up to 0.6%) and Abies (up to 0.6%). Betula sect. Nanae/Fruticosae (2–5.2%) and Salix (up to 3.2%) are the most representative boreal shrub taxa. Together with existing modern and fossil pollen data from the wider study region, the current record provides further evidence for the long‐debated presence of boreal trees and shrubs in Eastern Siberia throughout the LGM. Our results show that the Upper Lena was a region in which refugia for arboreal taxa existed and that far‐distant pollen transport can be ruled out as the source of the detected arboreal pollen.

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