TOWARDS BETTER UNDERSTANDING EUROPEAN ICE AGE POLLEN RECORDS: A LESSON FROM MODERN POLLEN ASSEMBLAGES OBTAINED FROM YAKUTIAN LAKES
Abstrakt
Pollen analysis of lake sediments and peat accumulations has been, over more than a century, the most widely used method to reconstruct past vegetation cover and character of the landscape. Sophisticated models considering pollen-vegetation relationship are often calibrated in current conditions (modern landscapes, climates) and seem to be robust enough to enhance reliability of reconstructions of the Holocene vegetation cover and its changes (e.g.
Abraham et al. 2016). However, the same approach can be hardly applied to European records of the coldest (cryocratic) stages of the Pleistocene.
In these records, high proportions of non-arboreal pollen (NAP), especially Poaceae and Artemisia, are often canonically interpreted as the evidence of treeless vegetation. Small proportions of arboreal pollen (AP) are then often considered to be a result of long distance transport.
Based on this traditional reconstruction, the glacial vegetation is usually interpreted as a steppe, tundra, or "steppe-tundra", with its closest recent analogy in southern Siberia (Kuneš et al. 2008, Magyari et al. 2014). We asked the following question: Is this traditional reconstruction of European cryocratic vegetation, as being mostly treeless, always valid? To solve this question, we compared fossil pollen data from the Ice Age in central Europe with the modern ones, obtained from treeless regions in southern Siberia, as well as from central Yakutia covered by taiga.
We analyzed pollen in 12 surface sediment samples from small alas lakes located in a flat landscape in central Yakutia. All the sampled lakes were surrounded by dense northern taiga, dominated by Larix with admixture of Pinus, Betula and (near streams) Picea.
Nevertheless, the lakes, although similar in size, differed in vegetation characteristics of their proximal surroundings - usually, there was a belt of steppe and/or meadow vegetation near the lakeshore.