Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia (original) (raw)
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Holocene environmental history on the eastern slope of the Polar Ural Mountains, Russia
Boreas, 2006
The Holocene environmental history of the eastern slope of the Polar Ural Mountains has been reconstructed using pollen, spores, algae and other microfossils from the Chernaya Gorka palsa section (67805?N, 65821?E, 170 m a.s.l.). An initial oligotrophic lake was formed at the study site c. 9800 Á9500 14 C yr BP. Although tundra communities dominated the vegetation in the area, birch and larch trees might have grown at lower elevations. Dry and disturbed soil habitats also occurred around the lake. Algae (mostly Pediastrum and Botryococcus) started to expand in the lake as climate gradually improved after c. 9500 14 C yr BP. However, the role of mosses (mostly Calliergon and Drepanocladus) was most important for the infilling of the lake basin. Increased temperatures and subsequent improvement of hydrological conditions resulted in vegetation changes: stands of willows developed rapidly and the role of tree birch in the local vegetation increased. The lake was completely filled at c. 8600 14 C yr BP. Peat accumulation started with Bryales mosses and, later, Sphagnum became dominant. Stands of Larix, Picea and Betula became well developed during the Boreal climate optimum. Tree birch began to spread into the tundra. Different Bryales mosses formed peat c. 8000 Á6500 14 C yr BP. Cyperaceae later became the main peat-forming element. Dense spruce canopies with Larix sibirica and Betula pubescens surrounded the study site during the Atlantic period, pointing to the warmest climate during the Holocene. Summer temperatures might have been up to 3 Á48C higher than today. However, a decline of spruce and an increase of birch around 6700 Á6300 14 C yr BP may reflect some climate deterioration. There are no dated deposits younger than 6000 14 C yr BP. It is assumed that Subboreal climate deterioration resulted in the development of permafrost and formation of the palsa at the site. The deposits, now protruding above the surrounding terrain, were eroded by wind, water and cryogenic processes.
Journal of Quaternary Science, 2021
A detailed, well-dated record of pollen and sedimentary ancient DNA (sedaDNA) for the period 15 000-9500 cal a BP describes changes at Lake Bolshoye Shchuchye in the Polar Ural Mountains, located far east of the classical Lateglacial sites in western Europe. Arctic tundra rapidly changed to lusher vegetation, possibly including both dwarf (Betula nana) and tree birch (B. pubescens), dated in our record to take place 14 565 cal a BP, coincident with the onset of the Bølling in western Europe; this was paralleled by increased summer temperatures. A striking feature is an early decline in Betula pollen and sedaDNA reads 300 years before the onset of the Younger Dryas (YD) in western Europe. Given the solid site chronology, this could indicate that the YD cooling started in Siberia and propagated westwards, or that the vegetation reacted to the inter-Allerød cooling at 13 100 cal a BP and did not recover during the late Allerød. During the YD, increases in steppe taxa such as Artemisia and Chenopodiaceae suggest drier conditions. At the onset of the Holocene, the vegetation around the lake reacted fast to the warmer conditions, as seen in the increase of arboreal taxa, especially Betula, and a decrease in herbs such as Artemisia and Cyperaceae.
Holocene Treeline History and Climate Change Across Northern Eurasia
Quaternary Research, 2000
Radiocarbon-dated macrofossils are used to document Holocene treeline history across northern Russia (including Siberia). Boreal forest development in this region commenced by 10,000 yr B.P. Over most of Russia, forest advanced to or near the current arctic coastline between 9000 and 7000 yr B.P. and retreated to its present position by between 4000 and 3000 yr B.P. Forest establishment and retreat was roughly synchronous across most of northern Russia. Treeline advance on the Kola Peninsula, however, appears to have occurred later than in other regions. During the period of maximum forest extension, the mean July temperatures along the northern coastline of Russia may have been 2.5°to 7.0°C warmer than modern. The development of forest and expansion of treeline likely reflects a number of complimentary environmental conditions, including heightened summer insola-tion, the demise of Eurasian ice sheets, reduced sea-ice cover, greater continentality with eustatically lower sea level, and extreme Arctic penetration of warm North Atlantic waters. The late Holocene retreat of Eurasian treeline coincides with declining summer insolation, cooling arctic waters, and neoglaciation.
Quaternary International, 2018
Climate change and human activity considerably influenced the temperate European deciduous forests through the Holocene, with the anthropogenic impacts being detected even in currently protected areas. This paper is focused on the area of the Kaluzhskiye Zaseki Nature Reserve, which contains remnants of primary broadleaved forests in central European Russia. Here, we present a new multi-proxy record including pollen, plant macrofossils, charcoal, loss on ignition and radiocarbon dating from the Mochulya peatland supplemented by 14 radiocarbon dates of charcoal fragments from soil pits in the study area. The results show that Mochulya peatland was a fen throughout the most of the time it existed. During the last 4200 cal yr BP the study area was occupied by broadleaved forests of Quercus, Ulmus, and Tilia. Picea became relatively abundant after 2300 cal yr BP. Despite the long-term human impact, vegetation fragments of these forests have persisted in the area until the present. Three main periods of deforestation and frequent fires were identified: 3700-3200 cal yr BP, 2000-1600 cal yr BP (the Early Iron Age) and 1000-400 cal yr BP (the Medieval Period). Whereas human-induced vegetation changes were apparent during the last two periods, vegetation dynamics during 3700-3200 cal yr BP were likely caused, at least in part, by climatic factors.
Trees in the Upper Treeline Ecotone in the Polar Urals: Centuries-Old Change and Spatial Patterns
Mountain Research and Development, 2020
Woody vegetation at the upper limit of its growth is a sensitive indicator of climate change. The aim of this study is to provide an analysis of the centuries-old spatiotemporal dynamics of larch trees at the upper limit of their growth (mountain massif Rai-Iz, Polar Urals, Russia). We used a ground-based method of mapping the remnants of trees that grew in the study area and died during the Little Ice Age. Aerial photographs from the 1960s and high-spatial-resolution satellite images from 2015 were used as data sources to define the locations of trees. Maps of the forest–tundra phytocoenochoras (areas of the terrain that are relatively homogeneous for one or more components of vegetation and/or other indicators) were created using a modified method of boundary detection between forest parcels with different stand densities. The proposed method of boundary detection between the main types of phytocoenochoras allowed us to identify a 15% total increase in areas of closed and open for...
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.