Characterised by heterogeneous microclimatic conditions, a sharp vegetation gradient and a rich archaeological record, Olkhon Island offers a unique setting to investigate past climate change and its potential influence on cultural trajectories in the Lake Baikal Region (LBR). Palynological and geochemical analyses of the uppermost 556 cm section of the 750 cm long, radiocarbon-dated sediment core (Nur-II) from Lake Nurskoye (53 degrees 3'N, 106 degrees 58'E; 456 m a.s.l.) at the western end of Olkhon Island reveal several long-and short-term climate shifts over the last 8800 years. Forest expansion beginning in the Early Holocene peaked during the second half of the 7th millennium cal BP, followed by a continuous decline culminating around 1500 cal yr BP, when open steppe vegetation reached its maximum extent. This pattern supports the long-debated hypothesis that landscape openness and the associated availability of herbivorous game were key drivers of population size, social practices and subsistence strategies among Mesolithic, Neolithic and Bronze Age hunter-gatherer communities in the region. The maximum expansion of steppe vegetation (ca. 3400-800 cal yr BP) likely attracted Bronze Age pastoral groups who migrated into the area around 3300 cal yr BP, as corroborated by the Nur-II palynological record and archaeozoological data from the LBR. However, the pollen data show no evidence that the mixed foraging-pastoral subsistence was supplemented by crop cultivation prior to the Middle Ages (i.e. 1360 cal yr BP). The pollen-inferred moisture trends on millennial to centennial scales, including the 8.2 and 4.2 ka BP cooling events, show a positive correlation with the intensity of the Asian summer monsoon circulation throughout the study period. This suggests that the region's hydrology was primarily controlled by a south-easterly circulation regime during the Early-Middle Holocene, while westerly-derived moisture became increasingly important after ca. 7000 cal yr BP.

The North Atlantic climate has been suggested to exert a major control on the hydroclimate of Inner Asia, but the direction and persistence of the temperature-moisture relationship remain unclear. Here, we present new varvechronology-constrained geochemical and mineralogical records from Lake Shira in northern Inner Asia, revealing a cyclical succession of centennial-scale wet-dry climate intervals over the past similar to 2500 years. Wet periods with high lake levels are interrupted by three arid intervals (350-479 CE, 1459-1534 CE, 1898-1928 CE), marked by low lake levels, high salinity and holomixis. The wet intervals coincide with the Roman Warm Period, the Medieval Warm Period and the middle-late Little Ice Age (LIA), and the dry phases with cold spells associated with the Dark Ages Cold Period and the beginning and end of the LIA. A phase of less intense aridity 349-296 BCE overlaps with the end of the Iron Age Cold Period. A thorough review of published climate data and our own findings shows that this pattern is primarily driven by thermal conditions in the North Atlantic region, where higher sea surface temperatures (reflected in elevated Atlantic Multidecadal Oscillation indices) promote more positive North Atlantic Oscillation states and intensify mid-latitude westerly moisture transport. Comparison of varve thickness measurements with observed/reconstructed climate records for the past 150 years indicates that sedimentation rate is mainly controlled by fluvial discharge to the lake. Although varve thickness tends to be negatively correlated with precipitation and temperature, several notable exceptions limit its use as independent climate proxy.

We present the results of a multiproxy study of a 144 cm long core of laminated sediments from Lake Shira in the northern Minusinsk Basin in order to understand the causal relationships between climate change, ecological responses, and hydrological variations. The new palynological record covers the last 2980 years with an average resolution of 21 years. Palynological results and biome scores indicate that steppe and meadow-steppe with sparse forests prevailed in the northern Minusinsk Basin during the Late Holocene. The lower part of the taiga belt in the mountainous frame of the basin was dominated by larch, and the middle part of the taiga belt was dominated by larch, pine, fir, and spruce. The gradually decreasing role of dark conifers indicates a regional trend towards climatic aridification in the Late Holocene. The ratio of Artemisia pollen to Chenopodiaceae pollen suggests that the semiarid climate of the northern Minusinsk Basin during the last 2980 years was repeatedly interrupted by short intervals of more humid climate. The low abundance of Botryococcus in the records from Lake Shira may be an indicator of lowered lake levels during the intervals of lake holomictic state ca. 2850-2800, 2000-1920 BP, 1320-1290 BP, 700-510 BP, and 120-70 BP. Comparison of new environmental records of the northern Minusinsk Basin obtained from Lake Shira with data on global climate fluctuations shows that changes in the regional vegetation and hydroclimate of Lake Shira in the Late Holocene were mainly caused by large-scale atmospheric circulation processes controlling the heat and moisture balance in South Siberia.

The study of herbarium materials of the Ephedra dahurica Turcz. collected in the Torey Lakes region in different years has revealed the morphological variability of its pollen grains. An inverse relationship has been established between the development of the number of pseudosulci and plicae (ridge) of pollen grains and the values of temperature and humidity during the growing season. During wet seasons, the plant produces pollen grains with few pseudosulci. The number of pseudosulci increases during dry and cool growing seasons.

There are a great number of lakes in the East Sayan Mountains that were formed during the Holocene epoch and keeps the most valuable archives of the regional vegetation and climate history. The high altitude position of the lakes makes their geosystems very sensitive to climate variations, since the air temperature changes faster in the highlands than in the plains.A thorough examination of high mountainous lakes and their historical variability under different climatic conditions can helpus better understand both the current climate warming and future changes in high-altitude environments. The article presents the study of the bottom sediments from the high-altitude lake Nomto-Hur and the peat deposits in the Sentsa river valley, which is hydrologically connected with the lake Nomto-Nur. The lake Nomto-Nur formed nearly 750 years ago due to the uplift of the erosion basis of the Sentsa river caused by formation of the lava-dammed paleolake Zun-Ukhergei. At present time, the lake Nomto-Nur is the outflow of the Sentsa river, which makes a comprehensive study of these two objects more interesting and useful on a general regional scale. A peat core obtained from the Senca river valley, that was dated by radiocarbon method, is estimated to be 4,700 years old. The spore-pollen record from the bottom sediments of lake Nomto-Nur is presented from its base. Thus, the article describes the results of the study of two cores in the range of years from 4 700 to the present, which is part of the late Holocene period. The results of spore-pollen analysis of both objects made it possible to reconstruct the sequence of paleoecological events inthis area, and also contributed to the understanding of the dynamics of landscape and climate changes in the region. During the study, the authors also recorded significant flood events in the study area approximately 700 and 400 years ago. The first probably led to the formation of lake Nomto-Nur, and also had a close connection with volcanic eruptions in the region during this period of time. A significant conclusion was made about the appearance of nomadic peoples engaged in cattle breeding in the research area about 600 years ago. The data also served to understanding the causes of modern warming and the nature of possible climate changes in high-altitudeareas in the future.

With the increase in global wildfire activity in response to global climate warming, the reconstruction of longterm fire histories and their links to environmental and anthropogenic factors has recently become an important focus of palaeoenvironmental research. Here we compare the precisely radiocarbon (14C) dated long-term histories of vegetation change and fire activity from lakes Ochaul (Cis-Baikal) and Kotokel (Trans-Baikal) in the Lake Baikal Region (LBR) of Siberia, a known source region of wildfires whose past and future relationships with climate, vegetation structure and human economy are still poorly understood. Our results show that under cold and dry glacial climate conditions (32-18.2 ka BP) fire frequencies in both study regions were low. Deglaciation, which was characterised by the spread of woody plants, began around 18.2 ka BP, accompanied by a slight increase in fire activity. Differences in the fire records from both subregions are observed from the end of the Lateglacial (LG), with peak fire activity in Cis-Baikal during the Early Holocene (EH) and in Trans-Baikal during the Middle Holocene (MH). During the Late Holocene (LH) both regions are marked by generally low fire activity. We propose that the long-term spatiotemporal differences in fire activity during the EH-MH interval are primarily driven by vegetation composition and landscape openness and the resulting changes in fire regime. Interestingly, both peaks are also observed in a global-scale fire record, which suggests spatiotemporal complexity of the Holocene fire history. Low charcoal accumulation rates in both records during the Middle Neolithic (ca. 6660-6050 a BP) "cultural hiatus" archaeologically documented for Cis-Baikal suggest an LBRwide population decline. On the other hand, the spread of Late Bronze and Iron Age cultures into the LBR from 3.5 ka BP may have at least partly driven the increase in fire frequency around Lake Kotokel.

The paper presents reconstruction of the geochemical evolution of the saline lake Shira (South Siberia, Russia) over the past 3000 years based on the elemental composition of bottom sediments. Based on the rock-forming element contents obtained by X-ray fluorescence analysis, the main geochemical indices were calculated to assess the degree of deformation and weathering of the rocks in the catchment basin, paleosalinity, paleoclimate, paleoproductivity and input of clastic materials. Changes in Al2O3 and TiO2 contents reflect the influence of the terrigenous contribution in the lake basin and demonstrate four decreases in the terrigenous removal contribution in the age intervals of 40-135, 580-800, 1900-2020 and 2780-2850 cal. a BP. These intervals are characterized by decreases of Na2O, SiO2, K2O and Fe2O3 contents and increases of MgO and CaO contents. The deceleration in the processes of physical weathering of terrigenous material from banks into the lake and its removal by watercourses is confirmed by the increase of the paleosalinity index and the decrease of chemical weathering. The four considered intervals are characterized by high values of the Ti/Zr ratio, which corresponds to rocks formed close to the provenance area. For the interval 2780-2850 cal. a BP, the change of the Ti/Zr ratio value is not so contrasting in comparison to the intervals 40-135, 580-800 and 1900-2020 cal. a BP. The mineral composition of the bottom sediments of saline lake Shira corresponds to young and immature clay mineral with a high percentage of primary silicate minerals, formed under cold climate conditions.

New AMS14C-dated records of changes in the natural environment of southern Siberia from varve sediments of Lake Shira (Minusinsk Basin) are presented. The results allow reconstructing the history of vegetation, biomes, climate, relative productivity of the lake system, changes in the lake catchment erosion, and water levels in the lake itself over the past 2980 cal. years with an average temporal resolution of 21 years. The new reconstructions indicate a wet regional climate between 2980 and 2650 cal yr BP and its gradual aridization later. At the same time, the climate of the basin itself was more arid, thus providing the development of steppe and meadow-steppe communities around the lake in the last 2980 years. Variations in the Artemisia/Chenopodiaceae pollen ratio, considered as an indicator of moisture available to plants, suggest a slight increase in the moisture level in the Minusa Basin from 2980 to 50 cal yr BP and its noticeable decrease in the last 50 years. Reconstructions show that changes in vegetation around Lake Shira in the Late Holocene were mainly caused by large-scale circulation processes that changed the regional moisture balance. Steppe vegetation turned out to be very sensitive to moisture changes on a decadal scale. No clear pollen indicators of anthropogenic impact on vegetation were found in the new pollen record.

The results of studying the bottom sediments of meromictic Shira Lake, located in the northern part of the Minusinsk Basin, are presented. The sediments are represented by varves, annual layered series, which make it possible to reconstruct the history of the regional natural environment with a high resolution. The age model is based on seven 14C dates. The proposed new palynological record from the upper part of the Shira-2021-II-1 core extends the previous record by 530 years, providing the reconstruction of the regional natural environment for the past 2980 calibrated years with an average resolution of 21 years. The reconstructions show a humid regional climate 2980–2650 BP, with the climate of the basin itself being more arid, providing the existence of steppe and meadow–steppe assemblages around Shira Lake for the past 2980 years. The trend of changes in the Artemisia/Chenopodiaceae pollen ratio, considered as an indicator of available moisture for plants, suggests a slight increase in the moisture level in the Minusinsk Basin in 2980‒70 BP and a noticeable decrease in the past 70 years. However, the increase was interrupted by short-term intervals of increased climate aridization. The reconstructions have shown that changes in vegetation around Shira Lake in the Late Holocene were mainly caused by large-scale circulation processes that changed the regional moisture balance. The steppe assemblages were the most sensitive to moisture changes on a decadal scale. Like the previous pollen record, the new one does not have clear pollen indicators of anthropogenic influence on vegetation. Only a noticeable increase in the birch pollen content in the past 50 years may indicate planting of greenery around the resort areas.

We present the results of a comprehensive study of Holocene sediments from high-mountain Lake Sagan-Nur located in East Sayan. The lake is freshwater and has glacial origin. The sediments have been studied by X-ray diffractometry (XRD), IR spectroscopy, laser grain-size analysis, X-ray fluorescence analysis, AMS (14С) and 210Pb dating. The mineral composition of lake bottom sediments is dominated by phyllosilicates, quartz and feldspars. The method of mathematical modeling of their complex XRD profiles was used for correct identification of layered silicates. It has been established that the structural characteristics and quantitative ratios of these minerals change in response to climate changes in the region. The study of sediments composition and, especially, the precision mineralogical-crystallochemical analysis of layered silicates allowed us to reconstruct the climatic conditions of sedimentation.

New widely accepted scenario of glacier -free landscape evolution in the north of West Siberia during MIS 2 (Sartanian cryochron) raises a challenge to find new regional stratigraphic markers in the absence of reliable continuous sedimentary units. The cryogenic and pedogenic structures have been long applied for the European Late Pleistocene stratigraphy in the extra -glacial regions. We argue that such structures might also provide important markers for the detailed stratigraphic scheme in the north of West Siberia. Two types of indicators were suggested. Firstly, morphological features and ranges of radiocarbon dates in epigenetic ice wedge pseudomorphs of higher terraces are sensitive to events of abrupt climate amelioration. Regional analysis of radiocarbon dates of ice wedge pseudomorphs indicated four warmer climatic events in the Late Pleistocene - the Early Holocene (ca. 18000-16500 cal BP, ca. 13800-12500 cal BP, ca. 11700-11100 cal BP, and ca. 10400-9000 cal BP). They correlate to climatic events of the Greenland ice core record with minor temporal lag. Secondly, more detailed cryogenic-paleosol-sedimentary sequences formed at lower terraces where sedimentation continued during MIS 2 are another type of suggested indicator. Their morphological and paleobotanical analyses and radiocarbon dating provided a reconstruction of local paleolandscape evolution with events of cryohydromorphic soil development (ca. 15700-15300 cal BP, ca. 11200-9000 cal BP). Similar late -glacial paleosols are encountered in the European loess sequences. We propose that the cryopedogenic horizons, including ice wedge pseudomorphs, cryoturbation structures, and cryohydromorphic paleosols, are reliable regional stratigraphic markers in the north of West Siberia for the Sartanian cryochron.

The results of studying bottom sediments taken from the high-mountain lake Sagan-Nur located on the Oka plateau (East Sayan Mountains), which is insufficiently studied, are presented. The lake is freshwater and has a glacial origin. Comprehensive investigations of the mineral composition of the lake sediments accumulated over the past 8600 cal. years have been carried out for the first time. The research methods include X-ray diffraction (XRD), infrared spectroscopy, laser granulometry, SiO2 bio determination, AMS, and 210Pb dating. The mineral composition of the bottom sediments is dominated by layered silicates, quartz, and plagioclase; furthermore, the X-ray amorphous component consisting of biogenic silica and organic matter is present. The method of mathematical modeling of their complex XRD patterns is used for correct identification of the layered silicates. It is established that the layered silicate assemblage is stable and is represented by muscovite, chlorite, illite, mixed-layer illite–smectite and chlorite–smectite, and kaolinite. At the same time, the structural characteristics and quantitative ratios of these minerals in the deposits changed significantly in response to changes in the natural environment of the region, which reveals the potential of a number of phyllosilicates (illite, mixed-layer minerals) as indicators of the paleoclimate in the bottom sediments of freshwater basins. The results of studying the sediment composition and, especially, the precision mineralogical–crystallochemical analysis of layered silicates have made it possible to reconstruct the paleolandscapes and climatic conditions of sediment accumulation and to assign them to the respective Holocene sub-stages.

In this study, we calculate the Holocene rates of vegetation composition changes (RoCs) for different elevations in the Central Arid Zone of Asia based on 46 pollen records using Detrended Correspondence Analysis (DCA). In addition, we investigate the relative importance of six drivers (temperature, precipitation, CO2 concentration, fire, pasture and cropland activities) using Structural Equation Modeling (SEM). Results show that RoCs at high elevations (>2000 m a.s.l.) were generally greater in the early Holocene and then fell to their lowest values at-6000 cal. yr BP. RoCs then gradually increased between-6000 and-3000 cal. yr BP and over the past-3000 years, RoCs abruptly decreased before returning to an upward trend. We infer that the changeable characters of RoCs at high elevations are mainly modulated by fire activities. RoCs at middle-to-low elevations (<2000 m a.s. l.) experienced a steady acceleration through the Holocene, which might be attributed to climatic cooling and wetting and intensification of fire activities. Our findings shed light on the Holocene response of vegetation to climate change, CO2 concentration, fire and human activities (grazing and cropland) in the Central Arid Zone of Asia.

Abstract The DIMA Network (Developing Innovative Multi-proxy Analyses – in Siberia and the Russian Far East (SRFE)) started from a small nucleus of palaeoenvironmental researchers in the UK and SRFE at a workshop in 2008 and currently includes researchers from over 25 institutions. The mutual interest in creating long-term records of environmental change was rekindled during workshops in Magadan (2018), Tomsk (2018) and Southampton (2019). These events were organised to connect researchers from the UK and SRFE with these aims: (1) provide training in new techniques and methods, (2) facilitate knowledge transfer about local sites and conditions, (3) stimulate large-scale collaborative projects across SRFE and (4) inspire a new generation of palaeoenvironmental researchers.

Long-term and continuous lake sedimentary records offer enormous potential for interpreting paleoenvironmental histories and for understanding how terrestrial environments might respond to current global warming conditions. However, sedimentary records that contain the Late Glacial and Holocene epochs are scarce in deep continental high-mountain regions. A 150 cm sediment core was obtained from Lake Kaskadnoe-1 in the East Sayan Mountains (South Siberia, Russia, 2080 m above sea level), containing a unique record of the last 13,200 calibrated years (cal yr). Chronological control was obtained by AMS 14C dating. Here, we show the first detailed X-ray fluorescence (XRF) geochemical record, with the goal of broadening our knowledge of the paleoenvironmental history of the East Sayan Mountains in the past. The determination of major compounds and trace elements (Sr, Zr) was performed from each centimeter of the Lake Kaskadnoe-1 sediment core. The inorganic geochemistry indicates significant variations in elemental composition between two major lithological units of the sediment core: the Late Glacial dense grey silty clay (150–144 cm), and the upper interval (0–143 cm) mostly consisted of dark biogenic-terrigenous silt, accumulated during the Holocene. The Late Glacial sediments accumulated 13,200–12,800 cal yr BP are characterized by high values of CIA, Mg/Al, K/Al, and Mn/Fe, and are depleted in Si/Al, Fe/Al, and Ca/Al. During the Younger Dryas cold episode, LOI enrichment was probably caused by the presence of less oxic conditions, as seen in lower Mn/Fe values, due to a longer period of lake ice-cover. The Early Holocene (12,000–7500 cal yr BP) is associated with a decreasing trend of mineral matter with fluvial transport to Lake Kaskadnoe-1 (low K/Al, Mg/Al) and stronger chemical weathering in the lake basin. The increase in Ti/Al, K/Al and CIA values over the last 7500 years suggests an increase in the terrigenous input into the lake. Low LOI values can be possibly explained by the presence of less dense vegetation cover in the basin. In summary, our data indicate that the geochemical indices and selected elemental ratios mirror the sedimentation conditions that were triggered by environmental and climate changes during the Late Glacial and Holocene.

In the current study, different geochemical and biological proxies, including pollen, non-pollen palynomorphs, ostracods and molluscs, from an AMS radiocarbon-dated sediment core from Lake Ochaul (54 degrees 14 ' N, 106 degrees 28 ' E; 641 m a.s.l.) are presented and discussed. Ochaul is a fresh-water lake and an archaeological site situated ca. 100 km northwest of Lake Baikal in the upper reaches of the Lena River. The 260-cm-long sedimentary record presented here spans the Lateglacial-Holocene interval, between ca. 13,500 cal yr BP and the present. The reconstructions of the postglacial vegetation and lake system development are discussed along with the regional climate dynamics and the hemispheric-scale environmental changes. During the Allerod interstadial the region around Lake Ochaul was dominated by sparse taiga forests. Cooling during the Younger Dryas led to a more open tundra landscape where trees formed patchy forest stands in climatically favourable environments. This facilitated a rapid spread of forests at the onset of the Early Holocene during which the study region was probably characterized by seasonally dry climate controlled by the interplay of higher insolation, lower global sea levels and remaining ice sheets in the North Atlantic region. After thermal and moisture optimum conditions and a maximum spread of forests during the Middle Holocene, continuous cooling and a trend to more open forests landscapes marked the Late Holocene. These long-term trends were interrupted by several relatively short episodes of change in the vegetation and algal records, which coincide with short-term (centennial-scale) Northern Hemisphere cooling/drying phases. This shows that the regional vegetation reacted sensitively to these climate oscillations. Six AMS radiocarbon dates of bone material of large herbivorous animals from the Ochaul archaeological site located at the northern shore of the lake provide important information about prehistoric hunter-gatherers and indicate that activities at the site took place at ca. 27,780-27,160 cal yr BP (95% probability range) as well as during the Mesolithic (ca. 8850-8450 cal yr BP), Early, Middle and Late Neolithic (between ca. 6840 and 5490 cal yr BP) and the Iron Age (ca. 2120-1930 cal yr BP). Our results demonstrate that despite major environmental transformations following the Last Glacial Maximum, Lake Ochaul and the Malaya Anga River valley remained attractive for large herbivores and for prehistoric hunter-gatherers, even during the Middle Neolithic cultural "hiatus" (ca. 6660-6060 cal yr BP) in Cis-Baikal, as documented by the published archaeological records.

ABSTRACTA new accerator mass spectrometry (AMS)‐dated sedimentary record from Lake Ochaul (54°14′N, 106°28′E; 641 m a.s.l.) in Eastern Siberia covers the interval from ca. 27 850 to 20 400 cal a bp at ca. 180‐year resolution and contributes to a better understanding of the complex spatial vegetation pattern during the Last Glacial Maximum (LGM). Non‐arboreal pollen taxa are abundant in the pollen assemblages (mean value ca. 92.6%), but boreal trees are represented by all major taxa that grow in the lake catchment today, including Betula sect. Albae (0.6–4.8%), Picea (0.6–2.8%), Pinus sibirica (Haploxylon type) (up to 1.5%), Pinus sylvestris (Diploxylon type) (up to 2%), Larix (up to 0.6%) and Abies (up to 0.6%). Betula sect. Nanae/Fruticosae (2–5.2%) and Salix (up to 3.2%) are the most representative boreal shrub taxa. Together with existing modern and fossil pollen data from the wider study region, the current record provides further evidence for the long‐debated presence of boreal trees and shrubs in Eastern Siberia throughout the LGM. Our results show that the Upper Lena was a region in which refugia for arboreal taxa existed and that far‐distant pollen transport can be ruled out as the source of the detected arboreal pollen.

This study presents the first radiocarbon-dated palynological record from a peat section (5749'10.03 "N; 11403'31.37 "E, 251 m above sea level) in the Mamakan area located in the lower Vitim River valley, about 350 km northeast of Lake Baikal. While the area is particularly renowned for its numerous multi-layered Upper Palaeolithic (ca. 50,000-14,000/10,000 cal yr BP) archaeological sites with rich cultural assemblages, there is also evidence for human occupation during the Mesolithic-Neolithic-Bronze Age period (ca. 14,000/ 10,000-3000 cal yr BP). However, the absence of accurately dated palaeoenvironmental records does not allow discussion of prehistoric human-environment interactions in this area. The records of pollen, spores and other non-pollen palynomorphs (NPPs) from the Mamakan site presented in this article document changes in the vegetation and climate of the study area between 6570 and 3630 cal yr BP. From 6570 to 6200 cal yr BP the vegetation around the site was dominated by sparse forests of mainly spruce and larch, indicating that the permafrost layer was located relatively close to the surface. Fir was part of the forest communities in habitats with a milder microclimate and a deeper permafrost layer. Around 6200 cal yr BP Scots pine started to spread across the study area. Until 4670 cal yr BP it dominated the pollen spectra of the Mamakan record, indicating warmer conditions. Climate cooling and higher soil moisture is indicated by the spread of Siberian pine and Siberian dwarf pine at the expense of Scots pine between 4670 and 3840 cal yr BP. From 3840 cal yr BP the Mamakan record suggests a landscape opening associated with the spread of Sphagnum-dominated bog vegetation and an increase in the occurrence of wildfires (3870-3820 cal yr BP), which were either natural in origin or caused by human activities. The spread of Scots pine paralleled by a decline in dark conifers (spruce and fir) and larch in the Lake Baikal Region (LBR) has been linked to a 'hiatus' in the Cis-Baikal archaeological records of the Middle Neolithic (6660-6060 cal yr BP). Around the Mamakan site this vegetation change occurred comparatively late, about 600 years later than in the regions around and east (e.g. Lake Baunt area) of Lake Baikal. The Mamakan pollen and NPP records, together with the available archaeological data, suggest that the environmental conditions in the lower Vitim River area may have sustained the hunter-gatherer lifestyle also during the 'hiatus' interval.

The first radiocarbon-dated pollen record from the Mamakan section is presented. This record has become the basis for the reconstruction of the vegetation and climate of the Middle Holocene in the Mamakan archaeological area, where a number of well-known Siberian archaeological sites of the Late Mesolithic–Middle Bronze period are located. Reconstructions suggest that sparse spruce and larch stands dominated in the area between 6450 and 6150 cal BP. Later, from 6150 to 4700 cal BP, Scots pine began to spread in a warmer climate than before, following the general trend of its expansion in the southern part of Eastern Siberia. A cooler climate than previously with increased soil and air humidity occurred in the Mamakan region from 4700 to 3840 cal BP, causing the regional expansion of Siberian pine. The time interval from 3840 to 3600 cal BP was characterized by the significant development of pine, spruce, and larch forests. On the basis of the age model, we assume that, in the lower reaches of the Vitim River and, probably, in other mountain regions north of Lake Baikal, Scots pine spread about 600 years later than in the Cis-Baikal region and east of the lake. This transition from dark coniferous-taiga to light coniferous-taiga with a predomination of Scots pine signifies the most fundamental change in vegetation of the Baikal region in the Holocene. This is often discussed as one of the possible causes of the Middle Neolithic cultural hiatus (6660–6060 cal BP), which has been documented in the archaeological records from different parts of this vast region. Reconstruction of vegetation in the Mamakan region suggests that the territory of the Nizhnii Vitim River has been favorable for humans during most of the hiatus recorded in the Cis-Baikal area and may have been considered as a refuge for populations of hunter-gatherers in the Middle Neolithic.