Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia (original) (raw)
Climatic and environmental changes in north-western Russia between 15,000 and 8000calyrBP: a review
Quaternary Science Reviews, 2007
Multi-proxy palaeoenvironmental studies of nine sediment sequences from four areas in north-western Russia reveal significant changes in climate, lake productivity and vegetation during the Lateglacial and early Holocene that show some degree of correlation with changes reconstructed from sites throughout the North Atlantic region. At Lake Nero in the Rostov-Jaroslavl' area, which is outside the maximum limit of the Scandinavian Ice Sheet, sedimentation recommenced shortly after 15 cal ka BP in response to increases in temperature and humidity during Greenland Interstadial 1 (GI-1; Bølling-Allerød). However, climatic amelioration during GI-1 was slow to increase lake organic productivity or trigger large-scale changes in much of northwestern Russia. In general, this region was characterised by long-lasting lake-ice cover, low lake productivity, soil erosion, and dwarf shrub and herb tundra until the end of Greenland Stadial 1 (GS-1; Younger Dryas). At some sites, distinct increases in lake organic productivity, mean summer temperatures and humidity and the expansion of forest trees coincide with rapid warming at the beginning of the Holocene and the increasing influence of warm air masses from the North Atlantic. At other sites, particularly on the Karelian Isthmus, but also in Russian Karelia, the delayed response of limnic and terrestrial environments to early Holocene warming is likely related to the cold surface waters of the Baltic Ice Lake, the proximity of the Scandinavian Ice Sheet and associated strengthened easterlies, and/or extensive permafrost and stagnant ice. These multi-proxy studies underscore the importance of local conditions in modifying the response of individual lakes and their catchments.
Postglacial history of East European boreal forests in the mid‐Kama region, pre‐Urals, Russia
Boreas
The Ural Mountains are an important climatic and biogeographical barrier between European and Siberian forests. In order to shed light on the postglacial formation and evolution of the boreal forests in the European pre-Urals, we obtained a peat sediment core, Chernaya, from the Paltinskoe bog located between the southern taiga and hemiboreal forest zone in the mid-Kama region. We carried out pollen analysis, non-pollen palynomorph analysis, loss-on-ignition tests and radiocarbon dating. Radiocarbon dated records provide centennial to decennial resolution of the vegetation and environmental history of the European pre-Urals for the last 8.8 ka. The postglacial formation of the pre-Uralian hemiboreal forests reveals four important phases: (i) the dominance of Siberian taiga and forest-steppe in the Early Holocene and beginning of the Middle Holocene (8.8-6.9 ka), indicating a dry climate; (ii) the spread of spruce and European broadleaved trees in the Middle Holocene (6.9-4 ka) under wetter climate conditions; (iii) the maximum extent of broadleaved trees coinciding with the arrival and spread of Siberian fir in the Late Holocene (4-2.3 ka); and (iv) the decline of broadleaved trees since the Early Iron Age (2.3 kapresent) possibly due to general climate cooling and logging. While temperate broadleaved trees possibly spread from local refugia in the Urals, fir arrived from Siberia and spread further west. The carbon accumulation rate of Paltinskoe bog (18.9AE10.16 g C m À2 a À1) is close to the average value of carbon accumulation of northern peatlands. Local development of peat is characterized by non-gradual growth with a phase of intensive carbon accumulation between 3.5 and 2.3 ka. The vegetation was strongly influenced by fire in the Early Holocene and by humans since the Early Iron Age practicing deforestation, agriculture and pasture. Phases of increased anthropogenic activity correlate well with the local archaeological data.
Diversity, 2020
Peatlands are remarkable for their specific biodiversity, crucial role in carbon cycling and climate change. Their deposits preserve organism remains that can be used to reconstruct long-term ecosystem and environmental changes as well as human impact in the prehistorical and historical past. This study presents a new multi-proxy reconstruction of the peatland and vegetation development investigating climate dynamics and human impact at the border between mixed and boreal forests in the Valdai Uplands (the East European Plain, Russia) during most of the Holocene. We performed plant macrofossil, pollen, testate amoeba, Cladocera, diatom, peat humification, loss on ignition, carbon and nitrogen content, δ13C and δ15N analyses supported by radiocarbon dating of the peat deposits from the Krivetskiy Mokh mire. The results of the study indicate that the wetland ecosystem underwent a classic hydroserial succession from a lake (8300 BC–900 BC) terrestrialized through a fen (900 BC–630 AD) ...
Treeline advances along the Urals mountain range - driven by improved winter conditions?
Global change biology, 2014
High-altitude treelines are temperature-limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest-tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub-Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11,100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade(-1) ), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05°C decade(-1) ). (ii) There was a positive correlation between canopy cover, snow ...
Quaternary Science Reviews, 2014
We describe and discuss the glacial and climate variations in the Polar Ural Mountains in northern Russia over the last 100 000 years. A series of optically stimulated luminescence (OSL) and radiocarbon ages from sediment cores demonstrate that there has been continuous deposition of lacustrine sediments throughout the last 65 ka in Lake Gerdizty, a lake basin situated on the eastern foothills of the Urals. Below the lacustrine sequence are two till beds; the uppermost (unit B) was probably deposited by a large mountain-centred glacier complex that covered the lake basin during Marine Isotope Stage (MIS) 4. This till bed might be a counterpart of the Usa Moraine in the western foothills of the Polar Urals, which is dated with OSL-and 10 Be cosmogenic nuclide methods to between 68 and 58 ka, consistent with the OSL ages from the lowermost lacustrine sediments in Lake Gerdizty. During this glaciation some of the northern Uralian outlet glaciers probably merged with the adjacent BarentseKara Ice Sheet that reached onto the adjacent lowlands forming large ice-dammed lakes on both sides of the Ural Mountains. The equilibrium line altitude (ELA) on the local ice cap was then at least 1200 m lower than at present. The pollen stratigraphy in Lake Gerditzy reflects an open tundra and steppe-like vegetation throughout MIS 3e2 (60e11,7 ka). The first significant change in vegetation, shown by an increase of dwarf-shrub communities of Salix and Betula, took place during the Lateglacial at around 15 ka or shortly after. Birch and spruce trees approached the area for the first time soon after the Holocene transition w11.7 ka, and became dominant elements in the vegetation after a few hundred years. Our reconstruction suggests a very cold summer climate during MIS 4 and presumably also during the preceding MIS 5b (95e85 ka) glaciation, probably amplified by the large ice-dammed lakes that existed during these two glaciations. A somewhat milder climate prevailed during MIS 3 (60e25 ka), but a treeless vegetation nevertheless suggests that mean summer temperatures did not exceed 10e12 C before the earliest Holocene.
Environmental Research Letters, 2009
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.
Using the territory of the Orlovskoye Polesye National Park as a case study within the catchment basin of the Oka River (Mid-Russian Uplands, Oryol Region, Russia), we obtained palaeoecological data for studying response of forest landscapes within the forest-steppe ecotone to climate change and human impact through the Late Holocene. The paper presents reconstruction of environmental change on a local to regional scales based on plant macrofossil, spore-pollen and testate amoeba records from a peat core along with reconstruction of woodland coverage inferred from pollen data. Over the past 4000 years, the total woodland coverage has fluctuated insignificantly, ranging from 38 to 52%, while the structure of the forest has changed radically. Prior to 1500 cal. yr BP, both birch-pine and mixed temperate deciduous forests of oak, elm, ash and lime with Scots pine and well-developed shrub understory of hazel and alder grew in the region. The subsequent agricultural colonization of the territory led to a reduction of a broadleaved trees in forest stands since 1500 cal. yr BP. During the last few centuries, human activity largely associated with cutting/burning trees and farming favored the expansion of secondary forests dominated by birch.
Global Change Biology, 2008
The ongoing climatic changes potentially affect plant growth and the functioning of temperature-limited high-altitude and high-latitude ecosystems; the rate and magnitude of these biotic changes are, however, uncertain. The aim of this study was to reconstruct stand structure and growth forms of Larix sibirica (Ledeb.) in undisturbed forest-tundra ecotones of the remote Polar Urals on a centennial time scale. Comparisons of the current ecotone with historic photographs from the 1960s clearly document that forests have significantly expanded since then. Similarly, the analysis of forest age structure based on more than 300 trees sampled along three altitudinal gradients reaching from forests in the valleys to the tundra indicate that more than 70% of the currently upright-growing trees are o80 years old. Because thousands of more than 500-year-old subfossil trees occur in the same area but tree remnants of the 15-19th century are lacking almost entirely, we conclude that the forest has been expanding upwards into the formerly tree-free tundra during the last century by about 20-60 m in altitude. This upward shift of forests was accompanied by significant changes in tree growth forms: while 36% of the few trees that are more than 100 years old were multi-stem tree clusters, 90% of the trees emerging after 1950 were single-stemmed. Tree-ring analysis of horizontal and vertical stems of multistemmed larch trees showed that these trees had been growing in a creeping form since the 15th century. In the early 20th century, they started to grow upright with 5-20 stems per tree individual. The incipient vertical growth led to an abrupt tripling in radial growth and thus, in biomass production. Based on above-and belowground biomass measurements of 33 trees that were dug out and the mapping of tree height and diameter, we estimated that forest expansion led to a biomass increase by 40-75 t ha À1 and a carbon accumulation of approximately 20-40 g C m À2 yr À1 during the last century. The forest expansion and change in growth forms coincided with significant summer warming by 0.9 1C and a doubling of winter precipitation during the 20th century. In summary, our results indicate that the ongoing climatic changes are already leaving a fingerprint on the appearance, structure, and productivity of the treeline ecotone in the Polar Urals.