The Response of the Southern Cis-Baikal Natural Environment to Climate Change and Anthropogenic Influence in the Late Holocene
E.V. Bezrukova1,2, N.V. Kulagina1,2
1Vinogradov Institute of Geochemistry SB RAS, Irkutsk,Russia
2Institute of the Earth’s Crust SB RAS, Irkutsk, Russia
Keywords: Southern Cis-Baikal, intrazonal steppes, bottom sediments, Late Holocene, palynology, landscape and climate changes, archaeological cultures, anthropogenic transformation
Abstract
The scarcity of palaeoecological reconstructions hinders the understanding of the patterns of environmental history in the Pre-Baikal region, as well as possible ways of human interaction with it, especially in the steppe areas of this vast region. Meanwhile, the ecosystems of such areas are very sensitive to global climate change, which emphasizes the importance of studying their climatic and ecological history. The aim of the research presented is to fill in part the knowledge gaps regarding the climate and vegetation of the Baikal region. We present the first results of the study of the physicochemical properties and palynomorph assemblages from the bottom sediments of Lake Ordynskoye, located in the intrazonal steppes of the Kuda River valley in the Pre-Baikal region. The chronology is based on a radiocarbon date for the base of the lake sediment section, supplemented by measurements of 137Cs and 210Pb isotope activity. The reconstructions suggest an alternation of humid and arid climate intervals on a scale from several decades to centuries in the interval from 2800 to 280 years BP (before present). The interaction of the North Atlantic Oscillation (NAO), the Siberian High (SH), and the regional climate likely played a significant role in the alternation of these wet-dry intervals. The profound changes in the vegetation of the Lake Ordynskoye basin and its limnosystem over the last approximately 280 years are attributed to the combined impact of regional climate and anthropogenic activities. The presented reconstruction of vegetation and climate in the Late Holocene is the first for the southern part of the Pre-Baikal region. It has shown that the coast of Lake Ordynskoye and the steppe areas in the Kuda River valley can be considered a unique location for studying paleocological variations in the Pre-Baikal region, their interconnections with regional cultural changes in the Iron Age and beyond.
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