Paleoclimatic reconstructions for the south of Valdai Hills (European Russia) as paleo-analogs of possible regional vegetation changes under global warming

Abstract

The possible response of forest ecosystems of south taiga at the south of Valdai Hills on projected future global warming was assessed using analysis of pollen, plant macrofossil and radiocarbon data from four profiles of buried organic sediments of the last interglacial and several cores from modern raised bogs and two small forest mires in the Central Forest State Natural Biosphere Reserve (CFSNBR; Twer region, Russia). The future pattern of climatic conditions for the period up to 2100 was derived using the data of A2, B1 and A1B emission scenarios calculated by the global climatic model ECHAM5-MPIOM (Roeckner E et al 2003 The Atmospheric General Circulation Model ECHAM 5. PART I: Model Description, Report 349 (Hamburg: Max-Planck Institute for Meteorology) p 127). The paleoclimatic reconstructions showed that the optimum of the Holocene (the Late Atlantic period, 4500-4800 14 C yr BP) and the optimal phases of the last interglacial (Mikulino, Eemian, 130 000-115 000 yr BP) can be considered as possible analogs for projected climatic conditions of the middle and the end of the 21st century, respectively. The climate of the CFSNBR during the Holocene climatic optimum was characterized by higher winter (about 3• C higher than at present) and summer temperatures (about 1• C higher than present values). Precipitation was close to present values (about 600-800 mm yr −1 ). Vegetation was represented by mixed coniferous and broad-leaved forest. In the warmest phases of the last interglacial the winter temperature was 5-8• C higher than present values. The summer temperatures were also about 2-4• C higher. Broad-leaved and hornbeam trees were the dominant tree species in vegetation cover.

Radiative Entropy Production along the Paludification Gradient in the Southern Taiga

“…Pollen analysis for central European Russia showed that in the second half of the Holocene (4500-0 14 C year BP), the increasing winter temperature resulted in the expansion of mixed coniferous broad-leaved forests, while cooling and moistening of the area resulted in an increasing area of pure spruce forests and the development of oligotrophic sphagnum bogs [51]. Under excessive moistening, some types of bogs exhibit intensive vertical growth, carbon accumulation, and may expand rapidly toward surrounding forests [25].…”

Early Holocene vegetation and climate dynamics in the central part of the East European Plain (Russia)

“…Our reconstructions of vegetation and climatic changes were based on previously published pollen records from the Staroselsky moch, Klukva mires, and Galich Lake (Velichko et al, 2001;Novenko et al, 2009bNovenko et al, , 2014a. The core chronologies were determined by radiocarbon dating, which was performed in the Radiocarbon Laboratory of the Institute of Geography of the Russian Academy of Science (Staroselsky moch and Klukva mires) and in the Leibniz-Laboratory for Radiometric Dating and Stable Isotope Research, the University of Kiel (Galich Lake, Table 1).…”

“…The lowermost radiocarbon age of the peat deposits is 9730 ± 100 cal BP. Pollen and plant macrofossil analysis and radiocarbon dating of this borehole have been presented in detail in Novenko et al (2009bNovenko et al ( , 2014a.…”

“…BP. The results of multiproxy studies of the Klukva mire were presented in detail in Novenko et al (2015).…”

“…Existing regional paleoenvironmental studies focused primarily on vegetation and climate reconstructions for the Late Glacial or the entire Holocene, but the Boreal period has only been described as a phase of relatively warm and dry climate with broadly distributed birch forests. Quantitative climatic characteristics for this period have been presented in Khotinski and Klimanov (1997), Velichko et al (2001), and Novenko et al (2009a). Climatic reconstruction from these studies agree relatively well with reconstructions for Northern and Central Europe, which together show a gradual increase in air temperature during the period (Sepp€ a and Birks, 2001;Davis et al, 2003;Barber et al, 2004;Sepp€ a and Poska, 2004;Allen et al, 2007), as well as strong climate fluctuations, such as the distinct "8.2 ka event" widely recorded in the North Atlantic and northern Europe at 8500e8000 cal BP (Alley et al, 1997;Baldini et al, 2002;Alley and Agústsd ottir, 2005;Thomas et al, 2007).…”