Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia (original) (raw)
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...
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.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2010
Radiocarbon-dated pollen and diatom records from Lake Kotokel in southern Siberia help to reconstruct the environmental history of the area since~47 kyr BP. Pollen spectra composition and reconstructed biome scores suggest predominance of a tundra-steppe vegetation and variable woody cover (5-20%) between~47 and 30 kyr BP, indicating generally a harsh and unstable climate during this interval, conventionally regarded as the interstadial within the last glacial. The short-term climate amelioration episodes in the glacial part of the records are marked by the peaks in taiga and corresponding minima in steppe biome scores and appear synchronously with the hemispheric temperature and precipitation changes recorded in the Greenland ice cores and Chinese stalagmites. Transition to full glacial environments occurred between 32 and 30 kyr BP. The interval at~30-24 kyr BP was probably the driest and coldest of the whole record, as indicated by highest scores for steppe biome, woody coverage b5%, absence of diatoms and reduced size of the lake. A slight amelioration of the regional climate at~24-22 kyr BP was followed by a shorter than the previous and less pronounced deterioration phase. The late-glacial (~17-11.65 kyr BP) is marked by a gradual increase in tree/shrub pollen percentages and re-appearance of diatoms. After 14.7 kyr BP the climate became warmer and wetter than ever during~47-14.7 kyr BP, resulting in the deepening of the lake and increase in the woody coverage to 20-30%~14.5-14 kyr and~13.3-12.8 kyr BP. These two intervals correspond to the Meiendorf and Allerød interstadials, which until now were interpreted as part of the undifferentiated Bølling/Allerød interstadial complex in the Lake Baikal region. The increase in tundra biome scores and pronounced change in the diatom composition allow (for the first time) the unambiguous identification of the Younger Dryas (YD) in the Lake Baikal region at~12.7-11.65 kyr BP, in agreement with the formal definition and dating of the YD based on the Greenland NGRIP ice core records. The maximal spread of the taiga communities in the region is associated with a warmer and wetter climate than the present prior tõ 7 kyr BP. This was followed by a wide spread of Scots pine, indicating the onset of modern environments.
Russian Journal of Ecology, 2013
Changes in the altitudinal position of the timberline in high mountain areas of the Nether Polar Urals and basic factors that influence such changes have been revealed on the basis of comparison of the age structure of Siberian larch (Larix sibirica) and arctic birch (Betula tortuosa) tree stands and photographs made in different years. On the mountain slopes studied, an upward shift of the timberline took place in areas covered in winter with thick snow (in the late 18th century), with Siberian larch being the pioneer species. Larch began colonizing areas with a thin snow cover in the 20th century. Birch appeared later and has since strengthened its positions. The increase in winter temperatures and precipitation facilitated the expansion of the forest.
Holocene vegetation dynamics and climate change in Kamchatka Peninsula, Russian Far East
Review of Palaeobotany and Palynology, 2013
We reexamined sixteen pollen records from non-volcanic areas in the Kamchatka Peninsula to reconstruct vegetation and climate changes during the Holocene. Pollen records were first summarized and evaluated for each of three main physiographic regions: (1) Western Lowland (WL), open to the Sea of Okhotsk (6 records); (2) Central Kamchatka Depression (CKD), bordered by mountains (4 records); and (3) Eastern Coast (EC), facing the Pacific Ocean (6 records), and then compared over the peninsula. The synthesized data suggest that the climate over Kamchatka was generally wet and mild before ca. 5.8 ka (1 ka=1000 cal. yrs BP) due to strong and prolonged maritime influence. The first forest maximum in the CKD started at ca. 8.9, indicating a warmer climate; however, forest spread along the both coasts was delayed until ca. 7 ka, suggesting a possible modulation of greater effective moisture on the coastal sites. The warmest period at ca. 7-5.8 ka is defined by the evidence of maximal forest extension overall the peninsula. During that time, birch (Betula) prevailed over alder (Alnus) in forest everywhere except in the EC. Since ca. 5.8 ka, divergent vegetation patterns became evident in northern vs. southern and coastal vs. interior sites that correspond with a shift from warmer/maritime climate to cooler/continental climate. Also, greater climate variability accompanied the Neoglacial cooling since 5.8 ka. This climate cooling, indicated by drastic shrub expansion, advanced southward from the northern coasts (ca. 5.8 ka) to the central interior and coastal areas (ca. 5 ka) and then to the south (ca. 3.5 ka). Subsequent warming, suggested by the evidence of a second forest maximum, advanced westward from the EC (ca. 5.2 ka) to the CKD (ca. 3.2 ka) and then to the WL (ca. 1.9 ka). An advance of larch (Larix) in the CKD since ca. 3.2 ka points to increased climate continentality and larger seasonal variations. In contrast, alder forest spread after ca. 1.7 ka, reported only from the southern EC and CKD sites, indicates a mild, maritime-like climate that also agrees with the first apparent advance of spruce (Picea) in the interior. The latest cooling event, indicated by another shrub expansion, shows eastward trend: it occurred much earlier at the WL (ca. 2.4-1.6 ka) then at the EC (ca. 900-350 cal. yrs BP), and was less evident in the CKD. Instead, there was a remarkable coniferous expansion during the last millennium when both larch and spruce invaded and replaced deciduous forests so that by ca. 450-320 cal. yrs BP, an extensive coniferous forest ("Coniferous Island") appeared in the interior of Kamchatka. Since ca. 300 cal. yrs BP, spruce expanded most rapidly what broadly coincides with the beginning of the Little Ice Age.
Rapid Lateglacial tree population dynamics and ecosystem changes in the eastern Baltic region
Journal of Quaternary Science, 2009
A growing body of evidence implies that the concept of 'treeless tundra' in eastern and northern Europe fails to explain the rapidity of Lateglacial and postglacial tree population dynamics of the region, yet the knowledge of the geographic locations and shifting of tree populations is fragmentary. Pollen, stomata and plant macrofossil stratigraphies from Lake Kurjanovas in the poorly studied eastern Baltic region provide improved knowledge of ranges of north-eastern European trees during the Lateglacial and subsequent plant population responses to the abrupt climatic changes of the Lateglacial/Holocene transition. The results prove the Lateglacial presence of tree populations (Betula, Pinus and Picea) in the eastern Baltic region. Particularly relevant is the stomatal and plant macrofossil evidence showing the local presence of reproductive Picea populations during the Younger Dryas stadial at 12 900-11 700 cal. a BP, occurring along with Dryas octopetala and arctic herbs, indicating semi-open vegetation. The spread of Pinus-Betula forest at ca. 14 400 cal. a BP, the rise of Picea at ca. 12 800 cal. a BP and the re-establishment of Pinus-Betula forest at ca. 11 700 cal. a BP within a span of centuries further suggest strikingly rapid, climate-driven ecosystem changes rather than gradual plant succession on a newly deglaciated land.