This study presents a multi-proxy reconstruction of Holocene growing season thermal conditions (GDD5) in Central Europe based on Betula nana subfossil leaf micro-phenology and pollen data from a 12-m-long sediment sequence at Linje peatland. A site-specific inference model was developed using modern B. nana leaves to estimate growing season heat accumulation. The model shows lower sensitivity compared to subarctic calibrations but captures variability in GDD5 within the local climatic range. Overlapping undulation index (UI) values observed in modern and subfossil material across differing thermal conditions highlight the importance of regional calibration. Reconstructed GDD5 trends indicate variability in growing season conditions during the Early Holocene and from ∼5450 cal. yr BP to the present and show the strongest agreement with pollen-based estimates during the first half of the Late Holocene. As GDD5 is an important factor controlling agricultural productivity, such reconstructions are important for understanding past changes in seasonality and their potential implications for prehistoric land use and settlement dynamics. The results demonstrate the applicability of combined micro-phenological and palynological approaches for reconstructing past growing season thermal conditions.

Late-Quaternary disruptions of the Atlantic Meridional Overturning Circulation (AMOC) have been linked to profound impacts on local and regional climate as well as vegetation. Temperature seasonality patterns during these AMOC events, most notably during the Younger Dryas, are not yet fully understood, as studies have shown two possible scenarios: overall cooling patterns in Younger Dryas, or warm summers with extreme winter cooling. Here we assess the seasonal temperature trends of late-Quaternary weak AMOC states in Northern Europe, based on new quantitative pollen- and plant macrofossil-based January and July temperature reconstructions using multi-method ensemble reconstruction approaches. For plant macrofossils, we implement a "dynamic" calibration approach, where a spatial extent of the modern calibration region varies based on an independent proxy for the past continentality regime. This allows the reconstruction to algorithmically select the most representative modern calibration region for each time slice. We find an indication that abrupt AMOC weakening is associated with winter-dominated cooling of up to 10 degrees C but relatively stable summers.

The Western Siberian peatlands rank among the largest in the Northern Hemisphere. This study investigates peatland development and palaeohydrological changes of the Mukhrino mire during the Holocene focussing on climatic, regional and local factors. The multiproxy and multi-core approach reveals spatial variability driven by topography and sedimentary conditions. Our study integrates testate amoebae, plant macrofossils, peat geochemical and biomarkers to provide insights into past vegetation and environmental conditions. Peat accumulation in Mukhrino mire began in the early Holocene, with regional vegetation influenced by climatic and soil factors. Forest cover has been present since the Early Holocene. Birch and pine dominated in the drained areas and episodic regional presence of Tilia and Ulmus indicated warmer intervals. Since ~8800 cal yr BP, Mukhrino mire transitioned to an oligotrophic/ombrotrophic state dominated by Sphagnum fuscum . A key focus of this study is the dynamics of peatland surface wetness over millennia. Proxy-specific responses revealed both short-term variability (via testate amoebae) and long-term climatic trends (via plant macrofossils). Local dry phases (~6500–5700/4700 and 2200–1800 cal yr BP) resulted in partial mire afforestation, while wetter periods (~5700/4700–2500 cal yr BP) facilitated the restoration of its current state. Comparisons with prior studies identified two wet and four dry zones, with synchronised wetness trends across cores despite localised variations in peat accumulation rates. A pronounced local wet phase (~6700–6800 cal yr BP) corresponds with a marker layer from nearby Lake Svetlenkoye sediments (~8000–6700 cal yr BP), attributed to Ob River palaeo-floods. This evidence supports the presence of regionally wet environmental conditions during this period.

During the Late Bronze Age and Early Iron Age (ca. 1100-380 BCE), the lands of central-eastern Europe were inhabited by the people of Lusatian Urnfield culture (LUc). They started functioning in the 14th century BCE and erected special types of strongholds (defensive settlements). In this article, we aimed to examine if a relatively short-term process of building a stronghold might have been recorded in the palaeoenvironmental archive of the Linje mire situated near Gzin-a case study stronghold in central-north Poland. It is a pronounced structure in the landscape, but its chronology is estimated only on ceramics. Our multi-proxy palaeoecological research, confronted with the archaeological data, revealed that LUc people were present in the Gzin area at least from ca. 1040 cal. BCE. We estimated that a minimum of 20-35 ha of oak-dominated woodland should have been felled for timber consumed only for the stronghold rampart. Indeed, erecting of the stronghold was marked by a synchronous decline in Quercus, Corylus avellana and Carpinus betulus pollen values at ca. 870 cal. BCE, and coincident with increased climate instability of the 2.8 ka event. Our study suggests that humans were a significant factor enhancing the impact of the 2.8 ka event on the woodland ecosystem, as societal reaction required increased consumption of timber. Moreover, strongholds in prehistory, no matter time and location, might have significantly influenced woodland ecosystems, leaving the footprint even in remote palaeoecological archives.

A multiproxy study of a sediment sequence from a Qu & eacute;bec peatbog characterises the rapid and significant environmental responses to changing climatic conditions from the deglaciation of the Laurentide Ice Sheet to the early Holocene period. Scotstown Bog (45 degrees 30'45.0"N, 71 degrees 11'42.0"W) is an ombrotrophic peatland on the edge of the Appalachian Uplands in southern Qu & eacute;bec, Canada. We reconstructed its Late-glacial and early Holocene palaeoenvironments for 14 000-6 000 cal a bp using palaeobotanical (plant macrofossil, macrocharcoal, pollen analyses), faunal (chironomid analysis), sedimentological (grain-size analysis, sediment organic content), and geochemical (sedimentary n-alkanes and hydrogen isotope analyses) methods. We targeted our multiproxy reconstruction on the Late-glacial period, which provides an example of how biota can respond to profound changes in climatic and environmental conditions. A major transition occurred between 13 000 and 12 900 cal a bp, which is recorded in all palaeoecological proxies. Our reconstruction reveals two major environmental changes at this time. First, the Scotstown basin became isolated from a larger proglacial lake, as shown by sedimentological changes, sediment grain size and chironomid assemblage shift. Second, plant macrofossils and pollen influx show contemporaneous major shifts in the vegetation composition from tundra to tree-line to closed-canopy forested communities.

Northern peatlands are significant terrestrial carbon stores but are increasingly threatened by human activities. Ombrotrophic peatlands, being naturally acidic, are particularly vulnerable to alkaline pollution. Despite their importance, the effects of alkalinisation on peatlands remain insufficiently studied. In Estonia, alkaline pollution from a cement industry and oil shale power plant emissions have degraded several peatlands since the 19th century. Although some sites have recovered in recent decades, more severely impacted areas remain in poor condition.We investigated the effects of alkalinisation on Varudi peatland, a forested site in northeast Estonia, which was exposed to 125 years of alkaline emissions from a nearby cement factory. Using a multi-proxy, high-resolution palaeoecological approach combined with a precise and reliable age-depth model, we reconstructed changes in environmental, chemical, botanical, and hydrological conditions over the past millennium. Our findings revealed three successional phases: during the mid-13th century CE, land clearance and increased mineral deposition caused the site to transition from a bog to a poor fen phase between approximately 1250-1570 CE; and while the cement factory operated without efficient filters, the site became a pine-dominated fen between 1871-1995.After the installation of filters in 1996, peatland pH returned to near pre-disturbance levels, and some recovery was observed. However, the site remains degraded. Our results indicate that alkalinisation significantly disrupts peatland functioning, reducing carbon storage and altering vegetation communities. These effects can persist for decades even after the source of contamination is removed, underscoring the need for more comprehensive monitoring of peatlands impacted by alkaline pollution globally.

The Eastern Baltic area stands out as a unique location due to the finds of Europe’s youngest dated mammoth remains (12.6–11.2 ka cal BP). Our study explores the drastic climate and landcover changes during the extinction of these gigantic herbivores at the Pleistocene/Holocene boundary. We used macrofossil analysis to determine the major contemporary terrestrial plant genera present in the area and used corresponding pollen taxa for REVEALS model-based landcover reconstructions. Our results indicate that these last mammoths utilised the open landcover of the Eastern Baltic, which developed as the continental ice sheet retreated during the termination of the last glaciation. Due to climate warming during the initial stages of the Holocene interglacial, the Eastern Baltic became speedily populated by birch and pine forests. The abrupt disappearance of typical forb-dominated tundra indicators, such as Dryas octopetala, and the fast increase in tree birch marked a shift from an open, tundra-like landscape to a forested one, making the environment inhospitable for mammoths even in northernmost Estonia by the beginning of the Holocene. A comparison between the isotopic values of nitrogen (δ15N) and carbon (δ13C) obtained from mammoths’ molars from 14.3 and 11.3 to 43.5 and 39.1 ka cal BP showed that mammoths experienced a decline in the nutritional value of their diet, resulting in their demise in the Eastern Baltic.

This study investigates the carbon and nitrogen isotopic composition of woolly mammoth (Mammuthus primigenius) remains from three Late Pleistocene paleontological sites in the southeast of the Western Siberian Plain (SEWS): Shestakovo, Krasnoyarskaya Kurya, and Volchia Griva. This region and time interval (28-22 ka cal BP) remain underrepresented in isotopic records, particularly for 613C and 615N values. We analysed 29 mammoth dentine samples, alongside dentine from one horse and one deer. Preservation quality was rigorously evaluated using established criteria, including C:N atomic ratios, collagen yields, and elemental carbon and nitrogen content. Our results reveal the densest concentration of the highest mammoth 615N values reported for the Northern Hemisphere. We attribute this isotopic enrichment to the unique local environmental conditions at Volchia Griva, including saline soils and intensive trampling, which may have altered nitrogen cycling at the site.

This study investigates the vegetation and hydrological dynamics of Linje peatland in northern Poland during the past similar to 11 500 years by integrating testate amoebae and plant macrofossil analyses. The Linje profile is currently the only complete Holocene peat record in Central Europe and offers valuable insights into long-term climate variability and its ecological consequences for peatland ecosystems. The results reveal significant changes in peatland wetness and vegetation driven by autogenic processes, climatic fluctuations and anthropogenic influences. Major bryophyte species turnovers occurred similar to 11 200, similar to 10 350, similar to 8200, 7500, similar to 5500, similar to 600, and similar to 450 cal BP often coinciding with declines in Archerella flavum and Hyalosphenia papilio abundances. Both proxies indicate a marked period of drier conditions between similar to 7600 and similar to 6800 cal BP corresponding with the Holocene Thermal Maximum. Additionally, testate amoebae data suggest further disturbances at similar to 3050, similar to 2000, and similar to 200 cal BP, and the latter, linked to a permanent shift in species composition, implies lasting changes to peatland conditions caused by intensified human activity. Around the end of the Early Holocene, most species turnovers and disturbances began to align with Holocene Rapid Climate Change (RCC) events.

We present a high-resolution, multi-proxy record from Mustj & auml;rve bog, northwest Estonia, covering the past similar to 2,500 years. By integrating paleoecological, historical, and climate data, we evaluate how climate and land use shaped peatland hydrology, vegetation, and carbon dynamics. The record reflects regional land-use history, confirming the usefulness of peatbogs as archives of land-use changes. Our profile identifies raised bog hydrology as a part of the surrounding catchment, and we discuss the susceptibility of these ecosystems to climate change. From the start of the record until ca. 700 CE, local agricultural activity was limited. After 700 CE, population growth and deforestation drove ecological instability, marked by reduced carbon accumulation, hydrological change, and increased fire activity. Since similar to 1960 CE, drainage has caused a long-term water table decline and arboreal encroachment. Our results suggest that past land-use changes have greatly affected the peatland ecosystem at Mustj & auml;rve. Despite this, Mustj & auml;rve appears to have been very resilient. Although there is no evidence for past critical transitions/thresholds, the current state of the Mustj & auml;rve peatland suggests high vulnerability, highlighting the importance of contemporary management practices to prevent further disturbances.

Peatlands are important ecosystems for carbon storage, storing an estimated 25-30% of global soil carbon despite covering just 3% of Earth’s terrestrial surface. These ecosystems are under increasing pressure due to human activity and climate change, which threaten to turn peatlands from being carbon stores to sources. Human activities such as peat draining are extremely damaging to peatland hydrology, and fire was often used by people as a tool for land management clearance in the past. Fire is one of the foremost forces impacting peatlands, as it destroys surface peat and the subsequent release of stored carbon. Fire frequency is predicted to increase due to more frequent and severe droughts in some areas, and increasing human activity in areas where peat can form (particularly in the Northern Hemisphere). These trends, if realised, can accelerate climate warming as previously stored carbon is released into the atmosphere.The focus of this study, Mustjärve bog, is an ombrotrophic peat bog located in northwest Estonia. Our project aims to assess changes in peatland fire regimes, vegetation dynamics, and hydrology to evaluate how the resilience of the site has changed over time within the context of relative changes in climate and human activity. A peat core was analysed using multiple palaeoecological proxies at high resolution (1 cm contiguous samples), to reconstruct past fire frequency, vegetation, and hydrological change over the past ~2500 years at the site. We also used historical data (population, past climate, and archaeological records) to better understand the drivers of changes uncovered in the palaeoecological record.Our data reveals a distinct anthropogenic signal from ~700 CE onwards, coincident with increasing population and expanding land exploitation. Human activity from ~700 CE to ~1800 CE causes an increase in local fire events, culminating in lowered carbon accumulation rates, lowered water tables and higher peat bulk density. This trend continued until ~1950 CE, when there was a recovery in carbon accumulation and water table depth. Mustjärve’s vegetation history was predominantly Sphagnum, with Sphagnum Sect. Acutifolia indicative of drier conditions becoming much more prevalent from ca. 200 BC onwards, possibly owing to changes in water table depth. In the last 150 years, arboreal taxa such as Pinus sylvestris and Betula nana have encroached onto the bog, reflecting a decreasing water table and increased human activity that has impacted hydrological conditions, such as peat draining. We find little evidence for a significant climate influence on Mustjärve bog, as anthropogenic pressures on the site appear to dominate over the palaeoclimatic signal.

This study examines the isotopic potential of mammoth remains from three paleontological sites in the southeast of the West Siberian Plain (SEWS): Shestakovo, Krasnoyarskaya Kurya, and Volchia Griva. We analysed oxygen isotopes from 29 mammoth enamel and tusk samples and horse and deer enamel samples. We verified sample preservation using ATR-FTIR and obtained delta 18 Op, delta 18 Oc, and reconstructed delta 18 Ow values for 28-22 ka cal BP. Preservation assessments revealed variable preservation conditions. Our findings indicate an increase of 1.4 parts per thousand parts per thousand in reconstructed delta 18 Ow values from glacial levels at 28-23 ka to late-glacial conditions at ca. 17-15.5 ka, likely reflecting climatic warming at the end of the Pleistocene. The extensive fossil material at these sites offers significant potential for further Last Glacial Maximum studies.

The recent advancements of new quantitative tools compatible with plant macrofossil proxy data have revived its potential for paleoclimate research. Plant macrofossils are commonly used in so-called indicator-species approaches, using methodologies that are typically built on known observations linking modern plant distributions with climate. This allows complementary paleoclimate reconstructions using an approach that is not limited by the spatial availability of calibration samples obtained from surface sediments (e.g., pollen or chironomids). We aim to evaluate the impact that various methodological choices have on the plant-macrofossil based reconstructions of January and July temperature patterns for the Lateglacial (14–11 ka BP) period. We use a variety of classic and novel quantitative climate reconstruction algorithms with plant macrofossil assemblages from 13 sites of the Baltic States. We use unfiltered plant data to evaluate the ability of each method to also handle the presence of plants that might have a weak sensitivity to temperature. Additionally, we test the influence of another methodological choice – the choice of modern calibration region – on the reconstructed climate. Our findings indicate that, with no prior filtering of summer and winter-sensitive plants, temporal temperature variations can be reconstructed with methods that implement probability density functions. Although some disparities in reconstructions are seen between the tested algorithms, we note that the choice of calibration region bears a greater influence on the results. A calibration region that best represents the past environment should be chosen rather than one representing the same spatial extent as the fossil site(s). Moreover, for long-term reconstructions, a "dynamic calibration set" approach should be considered in future studies by using a range of calibration regions and mirroring the continuously changing broadscale environmental regime of the past.

Spring onset is an important phenological observation that is sensitive to modern climate change and can be traced back in geological time. The Late Glacial (∼ 14 500–11 700 cal yr BP) spring onset and growing season (growing degree days) dynamics in the eastern Baltic region were reconstructed using the micro-phenological approach based on the dwarf birch (Betula nana) subfossil leaf cuticles. The presented study sites, Lake Lielais Svetinu (eastern Latvia) and Lake Kosilase (central Estonia), are located ∼ 200 km apart in the region affected by the south-eastern sector of the Scandinavian Ice Sheet. During the Late Glacial period the region and its biota were influenced by the retreating glacier and the different stages of the Baltic Ice Lake. The plant macrofossil data confirm that the study sites were in different vegetation zones (arctic-to-boreal) during the Late Glacial period. The dynamics of the estimated length of the growing season and spring onset, combined with the regional collection of plant macrofossil records, suggest the importance of local settings to species migration. During the Late Glacial warming period (Bølling–Allerød), a notable spring warming and longer growing season was calculated based on micro-phenology, but the treeline did not extend beyond central Estonia. The comparison of pollen- and chironomid-inferred past temperature estimations with spring onset, growing degree days, and plant macrofossil data shows coherent patterns during the cooler Older Dryas and warmer Bølling–Allerød periods, while suggesting more complicated climate dynamics and possible warmer episodes during the Younger Dryas cold reversal.

Spring onset is an important phenological observation that is sensitive to modern climate change and can be traced back in geological time. The Late Glacial (∼ 14 500–11 700 cal yr BP) spring onset and growing season (growing degree days) dynamics in the eastern Baltic region were reconstructed using the micro-phenological approach based on the dwarf birch (Betula nana) subfossil leaf cuticles. The presented study sites, Lake Lielais Svetinu (eastern Latvia) and Lake Kosilase (central Estonia), are located ∼ 200 km apart in the region affected by the south-eastern sector of the Scandinavian Ice Sheet. During the Late Glacial period the region and its biota were influenced by the retreating glacier and the different stages of the Baltic Ice Lake. The plant macrofossil data confirm that the study sites were in different vegetation zones (arctic-to-boreal) during the Late Glacial period. The dynamics of the estimated length of the growing season and spring onset, combined with the regional collection of plant macrofossil records, suggest the importance of local settings to species migration. During the Late Glacial warming period (Bølling–Allerød), a notable spring warming and longer growing season was calculated based on micro-phenology, but the treeline did not extend beyond central Estonia. The comparison of pollen- and chironomid-inferred past temperature estimations with spring onset, growing degree days, and plant macrofossil data shows coherent patterns during the cooler Older Dryas and warmer Bølling–Allerød periods, while suggesting more complicated climate dynamics and possible warmer episodes during the Younger Dryas cold reversal.

ABSTRACTThe latest data on holes in the spinous processes of the vertebrae of woolly mammoths, a rare pathology, are presented. This was identified at 19 sites of northern Eurasia. Such destructive changes are recorded ca. 34–12k 14C a bp, and only two sites dated to >50k and >41k 14C a bp. The main hypotheses about hole formation are: vertebral abnormalities; bone infections; genetic traits; and unfavourable geochemical environment. The pathology occurred in mammoths of all age groups, and could have arisen at the embryonic stage. There are two types: classic holes associated with osteolytic changes; and very rarely tumour‐like lesions. The most likely cause of the lesions is alimentary osteodystrophy caused by chronic mineral starvation. The aetiology of this disease is usually associated with a deficiency or excess of macro‐ and microelements in the geochemical landscape, and through forage and water this leads to a severe metabolic disorder. Analysis of palaeopathological data shows two waves of geochemical stress in animals, ca. 26–18k and ca. 16–12k 14C a bp. Therefore, the woolly mammoth extinction can be viewed as a non‐linear function, with two peaks of high mortality corresponding to the Last Glacial Maximum and the Lateglacial.

The hemispheric-scale climatic fluctuations during the Holocene have probably influenced the large Siberian rivers. However, detailed studies of the West Siberian Plain postglacial environmental change are scarce and the records of millennial-scale palaeohydrology are nearly absent. This paper presents the Holocene palaeoecological reconstruction based on the sedimentary record of Lake Svetlenkoye, located near the confluence of major Siberian rivers Ob and Irtysh. Postglacial history of flooding, dynamics of regional and local vegetation, sedimentation regime, geochemical changes and lake water pH were reconstructed based on multi-proxy studies. We used palaeobotanical (plant macrofossils, pollen, diatoms), geochemical (organic matter, total organic carbon and nitrogen content, carbon/nitrogen ratio) and chronological ( 14 C dates, spheroidal fly-ash particle counts) methods. The studied sediment section started to accumulate ~11,400 cal. yr BP. The initial shallow water body was flooded by Ob River waters ~8100–8000 cal. yr BP as confirmed by a remarkable increase in the sedimentation rate and the accumulation rate of the aquatic vegetation proxies. The period of flooding coincides with the high humidity periods reconstructed from regional palaeobotanical records. About 6800–6700 cal. yr BP, the study site became isolated from the Ob River floodplain and remained a small lake until present. The diatom-based lake water pH estimates suggest fluctuations in the pH values during the Holocene, the recent decrease since 1960s being the most notable. The vegetation record revealed constant postglacial presence of tree taxa – Betula, Pinus and Picea – although in different pollen ratios and accumulation rates through time. The paludification of the surroundings occurred since ca. 8500 cal. yr BP.

This study of the Kanna calcareous spring fen on Saaremaa, the largest island of Estonia, elucidates its history of fen development and vegetation diversity over the last 9,200 years. Pollen, spores, non-pollen palynomorphs, macrofossils, loss-on-ignition and humification index analyses were carried out to reconstruct fen succession, vegetation development, environmental changes and human impact. Hierarchical clustering, ordination analysis and linear regression were applied to examine the vegetation composition and richness patterns through time and to identify the potential environmental drivers underlying these patterns. Our results suggest reverse mire development from bog to fen, a rare occurrence and contrary to typical mire autogenic succession from groundwater fed to rainwater fed. Kanna developed as a small bog for the first 2,000 years from 9,200 to 7,200 cal yrs bp . Changes to the hydrological regime around 7,200 cal yrs bp , due to a warmer and drier climate and land uplift, caused a change from an ombrotrophic to a minerotrophic environment. Typical spring fen characteristics developed ca. 5,000 cal yrs bp and continued until ca. 400 cal yrs bp , when the fen was fed by calcareous mineral-rich groundwater and reached very high floristic diversity with various calciphilous and relict plant taxa. We conclude that general changes in the Kanna fen succession, vegetation community and diversity are associated with climatic changes. The present high diversity of the fen is a result of a long-term stable fen environment, which may have been even higher in the past. However, the pollen richness has decreased during the last 400 years, possibly due to human or natural factors.