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Abstract Worldwide reforestation has been recommended as a landscape restoration strategy to mitigate climate change in areas where the climate can sustain forest. This approach may threaten grassland ecosystems of unique biodiversity as such policies are based on the false assumption that most grasslands are man-made. Here, we use multiple lines of evidence (palaeoecological, pedological, phylogenetic, palaeontological) from Central Eastern Europe and show that various types of grasslands have persisted in this area throughout the postglacial i.e., the past 11,700 years. A warm and dry climate, frequent fires, herbivore pressure and early Neolithic settlements kept forests open until widespread forest clearance beginning 4000 to 3000 years ago. Closed forest cover has been the exception for the last two million years. This long-term persistence has likely contributed to the high biodiversity of these grasslands. Consequently, we call for a more cautious prioritisation of the protection of what may be erroneously considered natural, i.e. forests, by many environmental specialists and managers. Instead we provide a new framework for a better understanding of the evolution and persistence of different grassland types and their biodiversity, so that grasslands can be better understood, valued and conserved. Graphical abstract Unlabelled Image Highlights • We prove a new framework for understanding long-term dynamics of grasslands. • This framework facilitates the identification of ancient grasslands worldwide. • Evidence of the long-term grassland continuity in potential forest areas • Grassland continuity explains the high current species richness of this ecosystem. • Better classification highlights the importance of this overlooked environment. [ABSTRACT FROM AUTHOR]

Disturbances by fire are essential for the functioning of boreal/hemiboreal forests, but knowledge of long-term fire regime dynamics is limited. We analysed macrocharcoal morphologies and pollen of a sediment record from Lake Lielais Svētiņu (eastern Latvia), and in conjunction with fire traits analysis present the first record of Holocene variability in fire regime, fuel sources and fire types in boreal forests of the Baltic region. We found a phase of moderate to high fire activity during the cool and moist early (mean fire return interval; mFRI of ∼280 years; 11,700–7500 cal yr BP) and the late (mFRI of ∼190 years; 4500–0 cal yr BP) Holocene and low fire activity (mFRI of ∼630 years) during the Holocene Thermal Optimum (7500–4500 cal yr BP). Charcoal morphotypes and the pollen record show the predominance of frequent surface fires, occasionally transitioning to the crown during Pinus sylvestris-Betula boreal forests and less frequent surface fires during the dominance of temperate deciduous forests. In contrast to the prevailing opinion that fires in boreal forests are mostly low to moderate severity surface fires, we found evidence for common occurrence of stand-replacing crown fires in Picea abies canopy. Our results highlight that charcoal morphotypes analysis allows for distinguishing the fuel types and surface from crown fires, therefore significantly advancing our interpretation of fire regime. Future warmer temperatures and increase in the frequency of dry spells and abundant biomass accumulation can enhance the fire risk on the one hand, but will probably promote the expansion of broadleaf deciduous forests to higher latitudes, on the other hand. By highlighting the capability of broadleaf deciduous forests to act as fire-suppressing landscape elements, our results suggest that fire activity may not increase in the Baltic area under future climate change. [ABSTRACT FROM AUTHOR]

Fire frequency and severity are key parameters in evaluating fire-mediated changes in ecosystems, but these metrics are rarely reconstructed at extensive temporal scales. Notably our understanding of the role of fire regime dynamics in the functioning and biodiversity of Central Eastern European temperate forests is limited because investigation of the effect of fire has been neglected. To fill this gap in knowledge, we applied a multi-proxy approach (macrocharcoal, charred remains, pollen, plant macrofossils) to two sedimentary sequences spanning stands of closed canopy Picea abies to the P. abies treeline located in the northern Carpathians, Romania. We found that climate exerts a broad-scale influence, whereas vegetation feedbacks strongly modulate this fire-climate relationship. Fire has been almost continuously present throughout the Holocene with a remarkably stable mean fire rotation (∼250 yr) with fires of mostly low to mid severity and/or small to medium size. Humans have shifted the fire regime during the last 2800 years to slightly longer fire return intervals (mean 300 yr) and more biomass consumption per fire. We found that P. abies was favoured by low to moderate fire severity/area burned. The establishment of late-successional, shade tolerant Fagus sylvatica was facilitated by fire disturbances, but its expansion coincided with major gaps in fire events. This highlights the key role of fire in the expansion of F. sylvatica that seems only possible in a low/small to mixed severity/size fire regime with a sufficiently long fire return interval. High magnitude charcoal peaks negatively affected F. sylvatica . We found more diverse pollen assemblages, especially taxa linked to anthropogenic impact, at times of moderate fire disturbance corroborating the intermediate disturbance hypothesis. In terms of forest management, our results show that, contrary to current understanding, fire is a natural and important driver of vegetation change in this region. The anticipated increase in fire activity with the climate warming and/or augmented fuel accumulation may threaten the dominant forest ecosystems, given that these are adapted to low frequency and severity fires. We advise forestry to consider the effects of fire as part of climate-change conservation strategies. Diversifying the forest tree mixture with more fire-resistant native species is desirable in order to mitigate the effects of increased fire occurrence and severity. [ABSTRACT FROM AUTHOR]

High altitude environments are experiencing more rapid changes in temperature than the global average with the risk of losing essential ecosystem services in mountain environments. The Carpathians Mountains are regarded as hosting Europe's most pristine mountain ecosystems, yet the paucity of past environmental records limits our understanding of their sensitivity to the various drivers of change. A multi-proxy palaeoecological approach (plant macro-remains, pollen, charcoal) applied to three Holocene sediment sequences (between 1540 and 1810 m a.s.l.) in the Rodna Mountains documents past treeline and timberline shifts in response to climate change and human impact to anticipate the likely future responses. Our results indicate that forest reacted sensitively to past climate conditions. The timberline had exceeded an elevation of 1540 m a.s.l. by 10,200 cal. yr BP, when summers were warmer than today. The treeline remained below 1810 m a.s.l. at this time and reached its maximum elevation after 8500 cal. yr BP, when winter temperatures became milder. Cool summer conditions probably caused a lowering of the timberline and an extension of the treeline ecotone from 4900 cal. yr BP, a process accentuated by human impact from the Bronze Age (3500 cal. yr BP) onwards. The anticipated upslope tree movements as a consequence ongoing global warming are not yet clearly visible in our records, but will more probably take place in abandoned agricultural areas and be counter-balanced by re-enforced anthropogenic pressure elsewhere. Pinus sylvestris was the dominant tree species in the timberline under a warm and dry climate, when fires were frequent, during the early Holocene (11,250–10,200 cal. yr BP), while Picea abies became dominant in the timberline and Pinus mugo in the treeline ecotone, respectively from 10,200 cal. yr BP to the present. Abies alba became a significant component of the timber over the last four millennia. The anticipated future warmer and moister climatic conditions will favour the persistence of P. abies as well as A . alba . However, A. alba is more sensitive to anthropogenic disturbance, which implies that in places with continuing farmland pressure, A. alba may be less prevalent than P. abies in the future. Anthropogenic pressure is expected to increase the proportion of tree species characteristic of more disturbed forests and consequently threaten biodiversity with important implications for mountain ecosystem services. [ABSTRACT FROM AUTHOR]

Pollen datasets from central-eastern Europe, a region that for long time has been lacking quality palaeoecological records, are becoming increasingly available and these allow an evaluation of past vegetation sensitivity to climate change. Here, we use a new pollen and non-pollen palynomorph (NPP) record supported by eight AMS radiocarbon measurements from the Ic Ponor peat sequence, NW Romania, covering the end of the Lateglacial to mid-Holocene to examine the vegetation dynamics and associated climatic conditions. The vegetation at the Lateglacial to Holocene transition was composed of mixed forest ( Pinus dominated) -tundra-steppe vegetation. Following the decline of Pinus from 11,200 cal BP, Ulmus and Picea abies expanded and formed dense forests, then by Corylus avellana and Quercus from 10,200 cal BP. The forests were mainly composed of C. avellana and P. abies along with Ulmus , Quercus and Fraxinus between 9800 and 7440 cal BP. Starting with 7200 cal BP, P. abies dominated the landscape in the area probably favored by the increasingly cooler and moist conditions. After a considerable hiatus between 5830 and 40 cal BP, the most recent changes in the forest composition in the area were primarily related to forest clearings and grazing. The absence of relevant occurrences of Fagus sylvatica and Carpinus betulus in our sequence prior to 8800 cal BP, fail to give support to the glacial survival of these two taxa in the Apuseni Mountains, as hypothesized in the previous pollen and genetic studies. However, their continuous occurrence in small percentages after 8800 cal BP most probably reflects locally present, small populations of these taxa. Short-term phases of changes in the vegetation composition that appeared to be the response to cooler and/or wetter climate were recorded between 11,800 and 11,700, 11,500–11,200, 10,300–10,200, 9350–9250, 8250–8140, 7700–7400, 6800–6600 and 6100–5900 cal BP. These intervals correlate well to other centennial-scale excursions recorded in Romania and Europe. [ABSTRACT FROM AUTHOR]

Records of past climate variability and associated vegetation response exist in various regions throughout Central and Eastern Europe (CEE). To date, there has been no coherent synthesis of the existing palaeo-records. During an INTIMATE meeting (Cluj Napoca, Romania) focused on identifying CEE paleo-records, it was decided to address this gap by presenting the palaeo-community with a compilation of high-quality climatic and vegetation records for the past 60–8 ka. The compilation should also serve as a reference point for the use in the modelling community working towards the INTIMATE project goals, and in data-model inter-comparison studies. This paper is therefore a compilation of up to date, best available quantitative and semi-quantitative records of past climate and biotic response from CEE covering this period. It first presents the proxy and archive used. Speleothems and loess mainly provide the evidences available for the 60–20 ka interval, whereas pollen records provide the main source of information for the Lateglacial and Holocene. It then examines the temporal and spatial patterns of climate variability inferred from different proxies, the temporal and spatial magnitude of the vegetation responses inferred from pollen records and highlights differences and similarities between proxies and sub-regions and the possible mechanisms behind this variability. Finally, it identifies weakness in the proxies and archives and their geographical distribution. This exercise also provides an opportunity to reflect on the status of research in the area and to identify future critical areas and subjects of research. [ABSTRACT FROM AUTHOR]

Abstract: The usefulness of sedimentary charcoal records to document centennial to millennial scale trends in aspects of fire regimes (frequency, severity) is widely acknowledged, yet the long-term variability in these regimes is poorly understood. Here, we use a high-resolution, multi-proxy analysis of a lacustrine sequence located in the lowlands of Transylvania (NW Romania), alongside global climate simulations in order to disentangle the drivers of fire regimes in this dry climatic region of Central-Eastern Europe. Periods of greater fire activity and frequency occurred between 10,700 and 7100 cal yr BP (mean Fire Interval = mFI 112 yr), and between 3300 and 700 cal yr BP (mFI 150 yr), whereas intervals of lower fire activity were recorded between 12,000 and 10,700 cal yr BP (mFI 217 yr), 7100 and 3300 cal yr BP (mFI 317 yr), and over last 700 years (no fire events detected). We found good correlations between simulated early summer (June, July) soil moisture content and near-surface air temperature with fire activity, particularly for the early to mid Holocene. A climate–fire relationship is further supported by local hydrological changes, i.e., lake level and runoff fluctuations. Fuel limitation, as a result of arid and strongly seasonal climatic conditions, led to low fire activity before 10,700 cal yr BP. However, fires were most frequent during climatically drier phases for the remaining, fuel-sufficient, part of the Holocene. Our results also suggest that the occurrence of more frequent fires in the early Holocene has kept woodlands open, promoted grassland abundance and sustained a more flammable ecosystem (mFI < 150 years) whereas the decline in fire risk under cooler and wetter climate conditions (mFI = 317 years) favoured woodland development. From 3300 cal yr BP, human impacts clearly were partly responsible for changes in fire activity, first increasing fire frequency and severity in periods with fire-favourable climatic conditions (halving the mFI from 300 years to about 150 years), then effectively suppressing fires over the last several centuries. Given the projected future temperature increase and moisture decline and the biomass accumulation due to the agricultural land abandonment in the region, natural fire frequency would be expected to return to <150 years. [Copyright &y& Elsevier]

Abstract: Fire is recognized as a critical process with significant impacts on biota and the atmosphere. In this study, 11 micro- and macrocharcoal sedimentary records extracted from peat bogs and lakes at different elevations in the Carpathian region (in Hungary and Romania) were used to explore the patterns and the potential underlying mechanisms in biomass burning in this region during the last 15,000 years. Results from micro-charcoal and macro-charcoal data show similar trends in biomass burning and suggest that the major signal of both charcoal size-fragments relates mainly to local fires. Fire activity was low during the lateglacial, attained maximum values in the early Holocene (11,700–8000 cal. yr BP), become lower than present during the mid-late Holocene (8000–1000 cal yr BP), and increased again over the last 1000 years. The reconstructed spatial trends in biomass burning display different degrees of heterogeneity through time. Generally, there was more spatial similarity in fire activity across the study region during the lateglacial and early Holocene (15,000–8000 cal yr BP), followed by increased spatial heterogeneity from ca 8000 cal yr BP onwards. Biomass burning appears to have been primarily modulated by climate during both the lateglacial and Holocene, through its effect on vegetation productivity and therefore fuel availability (lateglacial), and fuel structure, moisture and flammability (the Holocene). Onsite human activities are likely to have provided an extra ignition source already in the early Holocene. However, evidence suggest that anthropogenic activities have markedly altered the natural trends in biomass burning from about 5500 yr BP (lowlands) and over the last 2000-1000 years (in the mountain environments), by either removing the biomass (in the lowlands) or igniting fire where it seldom occurs naturally (i.e., in the mountain environments). On the other hand, burning activity also appears coincident with significant changes in tree species compositions, indicating that fire has likely acted as a driving factor in forest dynamics. Results also suggest that peat deposits provide a more localized fire record than lakes, and that trends and patterns of change can be different even for sites situated close to each other. [Copyright &y& Elsevier]

Abstract: This paper examines fourteen fossil pollen datasets from Romania. It aims to investigate the temporal and spatial variability in the range distribution and abundance of three forest taxa, Pinus, Picea abies, and Quercus, during the Holocene. This is essential for understanding their current status in the forests of Eastern Europe, the conditions under which they arose, and the timing and processes responsible for their variability. Results from this synthesis do not indicate any apparent time lag in the establishment of Pinus diploxylon type (Pinus sylvestris and Pinus mugo), Pinus cembra, P. abies, and Quercus across Romania within the limits of the dating resolution. However, the onset of the mass expansion of P. abies was not uniform, spreading earlier from sites in the western and north-western Carpathians (11,000–10,500 yr BP) than in the east (10,000 yr BP). We found that sites from the western, north-western, and northern Carpathians contained higher abundances of P. abies, whilst Quercus was in higher abundances in sites from the east, but there was no regional distinctiveness in the abundance of Pinus across the study area. However, P. diploxylon type was found in much higher abundance than P. cembra. Additionally, results indicate a greater proportion of Pinus (mainly P. diplxylon type) at high elevations, P. abies at mid to high elevations, and Quercus at low elevations (<500 m). The dominance of Pinus in the early Holocene boreal forest is likely the legacy of its local glacial refugia, fast life history strategies, high stress tolerance, and large habitat availability. In contrast, Pinus exhibited poor competitive abilities and was quickly replaced with P. abies and temperate deciduous taxa after 10,500 yr BP. P. abies has persisted in large abundances at higher elevations (above 1000 m) until the present day, as a result of good competitive abilities, and resilience to climate change and disturbance. The long-term dominance of P. abies appears to have been spatially constrained, as populations below ca 1000 m were replaced by Fagus sylvatica from ca 4000 years ago, Recently, Pinus (mainly P. sylvestris) and P. abies have both experienced range expansions a consequence of forest management. Quercus is the only continental deciduous tree that has maintained high abundance throughout the whole Holocene. Members of this genus demonstrated high resilience to climate change and disturbance; following a period of decline it was capable of recovery during subsequent intervals of warm conditions or disturbance. [Copyright &y& Elsevier]

Abstract: Pollen analysis supported by nine AMS 14C dates from the Poiana Ştiol peat sequence (1540m), in the Rodnei Mountains, Eastern Romanian Carpathians (Romania) is used to reconstruct the Holocene vegetation history in this mountain region. The results are then compared with other sequences from Romania and Eastern Europe in order to better understand the past dynamics of the main forest constituents. The vegetation record at Poiana Ştiol starts at ca. 11,000calyr BP, with the occurrence of rather closed woodlands composed of Betula, Pinus, Picea abies, Alnus, A. viridis, and Ulmus. Picea abies was the dominant tree species for almost the entire period. However, during the last 3000years, P. abies forests were largely replaced by Pinus in the area. Temperate tree taxa (Fraxinus, Quercus, Acer, Tilia, and Corylus avellana) were also common but likely at lower elevation. C. avellana expanded around 10,300calyr BP and reached maximum values after 9000calyr BP. Pollen of Carpinus betulus and Fagus sylvatica was already recorded around 7000calyr BP. However, the spread of C. betulus occurred at ca. 6000calyr BP, with maximum values between 4800calyr BP and 3000calyr BP, while F. sylvatica spread from ca. 3200calyr BP and attained maximum values between 2000 and 200calyr BP. The first indications of human activities appeared around 3200calyr BP and intensified within the last 200years. Comparison with other sequences from Romania and surrounding countries reveals both similarity and great differences related to the location of glacial refugia, climate change and human impact. [Copyright &y& Elsevier]

Abstract: The forest ecosystem of the Apuseni National Park (ANP) in NW Romania is recognized for its high species and genetic diversity and is protected through various conservation measures. As ANP is the most populated natural park in Romania, the focus is on the need for communities to manage, sustain and prosper by using, exploring and sustaining the natural resources. But what activities are the most appropriate for the conservation of a highly diverse natural forest? This paper presents results from a long-term ecological study using fossil pollen, microscopic and macroscopic charcoal and AMS14C dating on a site in the ANP in order to examine how the interaction between climate change, human activities and other disturbances have shaped the present protected landscapes over the last 5700 years in this part of the reserve. Results from this study show that the landscape in this region has been continuously forested over the last 5700 years BP, but the forest composition and structure have been dynamic throughout much of the time. In particular, distinct changes in forest composition have occurred over the last 700 years of the record. Fagus sylvatica was the major taxon between 5200 and 200 years BP and its dominance is associated with the highest forest stability. The formation of the current Picea abies forests started 400 years ago and spruce became the dominant forest species during the last two centuries as a result of selective forest clearance, intensive grazing, and more recently, plantations. This led to a large reduction in forest diversity, decline of F. sylvatica and local extinction of several species including Abies alba, Ulmus, Tilia, and Acer. Our results show the high conservation values of A. alba and F. sylvatica in the ANP. Current management practices that allow the anthropogenic activities of timber production and fast tree regeneration, usually involving the plantation of P. abies in this part of the ANP are not in keeping with the NATURA 2000 objectives of ensuring the persistence of the most vulnerable species and habitats. [Copyright &y& Elsevier]

Pollen analyses and AMS 14C measurements were performed on lacustrine sediments and peat sequences from two former crater lakes (Preluca Tiganului, Steregoiu) situated in the Gutaiului Mountains in northwestern Romania, in order to reconstruct the vegetation development during the Lateglacial and Early Holocene.Before c. 14,700 cal. years BP (GS-2) open vegetation with shrubs (Salix, Juniperus), grasses and herbs (e.g. Artemisia and Chenopodiaceae) prevailed in the area. Around c. 14,700 cal. years BP and coinciding with the beginning of GI-1e, Pinus expanded, and patchy vegetation with scattered Pinus stands developed. The last 100 years of GI-1e (14,150–14,050 cal. years BP) were characterised by an increase in Pinus and Betula and an expansion of open forest communities. This development was shortly interrupted between 14,050 and 13,800 cal. years BP (likely corresponding to the cold phase GI-1d), when the tree cover became reduced and open vegetation with scattered Pinus individuals became frequent. The period with a significant expansion of Betula and Picea and the formation of an open forest (including Pinus and Ulmus), which took place between 13,800 and c. 12,950 cal. years BP, is tentatively correlated with GI-1c-a. A renewed reduction in tree cover (decrease of Picea and Betula, disappearance of Ulmus) started at ∼12,950 cal. years BP and at 12,600 cal. years BP forest stands were rapidly replaced by open vegetation communities with low shrubs (Salix, Juniperus), grasses and herbs (e.g. Artemisia and Chenopodiaceae). The period between 12,900 and 11,500 is correlated with the cold phase GS-1.At 11,500 cal. years BP, most likely as a response to the warmer climatic conditions at the beginning of the Holocene, an expansion of Betula and Alnus and, slightly later, also of Ulmus can be observed. Between 11,500 and 11,250 cal. years BP, open forests with Betula, Pinus and Ulmus were widespread in the area. At 11,250 cal. years BP dense forests dominated by Ulmus replaced the open forest type. Around 10,700 cal. years BP Quercus, Tilia and Fraxinus expanded strongly, and Acer and Corylus became established. Mixed deciduous forest with Picea dominated the upland vegetation between 10,700 and 10,150 cal. years BP. At 10,150 cal. years BP Corylus increased significantly and between 10,150 and 8500 cal. years BP, dense mixed deciduous forests with Picea and Corylus were abundant in the area.Climatic fluctuations seem to have been the driving force behind vegetation changes during the Lateglacial period, while the forest development during the Early Holocene was mainly driven by migrational and successional processes. [Copyright &y& Elsevier]

[Display omitted] • Multi-proxy long-term ecological studies are important tool to indicate peatland state. • Climate change and land cover in the catchment impact development of spring-fed fen. • Mollusc populations are sensitive to hydrological disturbances. • Restoring spring-fed ecosystems may also require catchment restoration. The calcareous substrate of spring-fed fens makes them unique islands of biodiversity, hosting endangered, vulnerable, and protected vascular plants. Hence, spring-fed fens ecosystems require special conservation attention because many of them are destroyed (e.g. drained, forested) and it is extremely difficult or even impossible to restore the unique hydrogeological and geochemical conditions enabling their function. The long-term perspective of paleoecological studies allows indication of former wetland ecosystem states and provides understanding of their development over millennia. To examine the late Holocene dynamics of a calcareous spring-fed fen (Raganu Mire) ecosystem on the Baltic Sea coast (Latvia) in relation to environmental changes, substrate and human activity, we have undertaken high-resolution analyses of plant macrofossils, pollen, mollusc, stable carbon (δ13C) and oxygen (δ18O) isotopes combined with radiocarbon dating (AMS) in three coring locations. Our study revealed that peat deposits began accumulating ca. 7000 cal. yr BP and calcareous deposits (tufa) from 1450 cal. yr BP, coinciding with regional hydrological changes. Several fire events occurred between 4000 and 1600 cal. yr BP, which appeared to have had a limited effect on local vegetation. The most significant changes in the forest and peatland ecosystems were at 3200 cal. yr BP associated with a dry climate stage and high fire activity, and then between 1400 and 500 cal. yr BP potentially associated with temperature changes during the Medieval Climate Anomaly (MCA) and Little Ice Age. Hydrological disturbances in the peatland catchment from 1400 cal. yr BP were most likely strengthened by human activity (deforestation) in this region. The relationship between the development of this peatland and changes in its catchment area, such as land cover changes or fluctuations in groundwater levels, suggest that protection and restoration of spring-fed fen ecosystems should also include the surrounding catchment. The presence of calcareous sediments, as well as appropriate temperature and local hydrological conditions appear to be the most crucial factors controlling Cladium marisus populations in our site - currently at the eastern limit of its distribution in Europe. [ABSTRACT FROM AUTHOR]

Wildfires in Siberia are documented to have increased in frequency and severity over recent decades. However, in the absence of long-term records, it is unclear how far and why this trend deviates from centennial to millennial scale variability. Here we reconstruct past patterns of fire frequency and fire type, and explore how the fire-related traits of boreal species and plant functional types (PFTs) determine ecosystem responses to changing fire regimes. We use charcoal-based reconstructions of the fire regime in combination with a pollen-based assessment of vegetation composition in two boreal forest peat profiles from Plotnikovo Mire in western Siberia that span the last 2400 and 5000 years. We found moderate levels of biomass burning between 5000 and 4000 cal yr BP. Biomass burning and fire severity i.e., more biomass burning per fire episode, increased over the last 1500 cal yr BP associated with the dominance of fire invaders (Betula). Conversely, between 4000 and 1500 cal yr BP lower biomass burning, with perhaps fire types affecting mostly litter and understorey vegetation, coincided with the dominance of fire resisters (e.g., Pinus sylvestris, P. sibirica, Larix) intermixed with a considerable number of fire avoiders (e.g., Abies sibirica and Picea obovata). This long-term perspective shows that the current fire regime commenced 1500 years ago and deviates from the trends observed over the last 5000 years. This deviation is linked to a combination of climate conditions conducive to fire, the amount and composition of woody fuels, and land use changes. Although pines reacted more sensitively to increased fire severity, the fire avoider Picea obovata appears to be much more vulnerable to both frequent, severe fires than Abies sibirica. We anticipate that climatically driven changes in fire weather, with frequent warm and dry spells, and anthropogenic land use intensification will heighten fire severity and their impact, driving vegetation composition towards Betula species to the detriment of Picea obovata. This study also shows that charcoal morphotypes can provide useful information on fuel and fire type, and that, although all macro-charcoal size classes reliably indicate local-scale fires, the larger fraction (>300–500 μm) allows the identification of on-site fire episodes. We recommend multi-site palaeo-fire reconstructions in boreal peatlands to adequately reflect the influence of localised peat moisture content, and vegetation composition and structure variability on the small-scale heterogeneity of fire type and spread. This will ensure that trends in fire regime dynamics are representative and not limited to the local scale. We also propose future directions in fire research that can be tested using fossil records of fire, climate and vegetation ideally in an interdisciplinary approach. Image 1 • Increased biomass burning and fire severity over the last 1500 years. • Frequent fires shifted vegetation cover towards fire-adapted Betula forest. • Pinus sensitive to increased fire severity, Picea obovata to both frequency and severity. • Charcoal morphotypes signal fuel type and fire severity. • Multi-site reconstructions recommended in boreal peatland to be representative beyond local scale. [ABSTRACT FROM AUTHOR]

The climate of Siberia is primarily influenced by the Siberian High (SH), although other large-scale atmospheric circulation systems, in particular North Atlantic Oscillation (NAO) storm tracks, play an important role. How variability in the relative strength and trajectory of these climatic systems has affected local to regional palaeoclimatic conditions remains little known. Here, we employ multi-proxy peat core analysis (δ13C, δ15N in Sphagnum , plant macrofossil, pollen, charcoal) from Plotnikovo Mire, part of the Great Vasyugan Mire in western Siberia (Tomsk province, Russia). We provide a high-resolution record of variations in climatic conditions and the biogeochemical fluxes of carbon and nitrogen over the past 2000 years and then discus the link between local climatic conditions and larger scale atmospheric circulation patterns. Our record shows that generally warm and dry conditions prevailed from BC 500 to 500 CE. Warm and wet episodes occurred during the early (800–950 CE) and later (1150–1300 CE) part of the Mediaeval Climate Anomaly (MCA), and were interrupted by a warm and dry mid-MCA phase (1000–1200 CE). Progressively cooler and wetter conditions established from 1400 CE, which became most marked between 1600 and 1850 CE, coincident with the Little Ice Age (LIA). Finally, drying of the mire surface reflects the warming trend of recent decades. We found that C accumulation was greater (90 g C m−2 yr−1) at times of wetter conditions and when Sphagnum was dominant, and lowest (35 g C m−2 yr−1) during periods of mixed vascular plant growth and Sphagnum under drier/unstable hydrological conditions. This peatland has been an active C sink over the past 1500 years, however, its ability to sequester carbon has decreased with recent warming and may continue to decrease with ongoing climatic warming and drying. We hypothesise that generally warm and moist conditions at the study site and over wider Siberia during the MCA could have been linked to a weakening of the Siberian High, which in turn enhanced the ingress of Atlantic moisture-carrying air masses across Siberia. Conversely, a strengthened SH overlapping negative North Atlantic Oscillation (NAO) modes during the LIA, resulted in a longer cold season with a delayed snowmelt and diminished evapotranspiration. This study shows that the interplay of moisture bearing air masses from different origins led to complex local hydroclimate and biogeochemical patterns. However, to resolve the spatio-temporal coherency of such climate variability due to the interaction of different air masses, and therefore better predict future climate changes, a denser network of palaeo-records is needed. • A mostly warm and wet MCA interrupted by a warm and dry middle phase. • Increasingly warm and dry in recent decades. • Cool and moist conditions during the LIA. • Changes in major atmospheric system prevalence impacted local palaeohydrology. • C and N accumulation sensitive to changes in hydroclimatic conditions and vegetation composition. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An electrochemical sensor was designed for N€(Carboxymethyl)lysine detection via DPV. • The sensor retains its electrochemical proprieties upon high mechanical deformations. • Great outcomes were obtained in presence of intrinsic and extrinsic interferences. • Raw human saliva was successfully employed in this study. • The sensor features high repeatability and lifetime storage. Abstract Advanced glycated end markers are involved in oxidative stress by producing long-term damage to proteins in ageing processes, atherosclerosis, and diabetes. The present work describes a cavitas printed electrochemical sensor for the direct salivary detection of N€(Carboxymethyl)lysine, a major advanced glycated end compound. The highly flexible and bendable sensor is integrated on a customized mouthguard placed on a phantom jaw that imitated the structure of the human oral cavity. The disposable sensor is readily attached on the mouthguard before usage and detached after the electrochemical investigation. Thus, it can be replaced whenever required. The sensor exhibits high selectivity and sensitivity in the phosphate buffer with a limit of detection of 166 ng/ml (equivalent to 0.81 μM) (over a range of 0.5–2500 μg/ml (equivalent to 2.45 μM–12.24 mM) N€(Carboxymethyl)lysine by employing a differential pulse voltammetry analytical procedure. Moreover, the cavitas sensor was tested in raw, untreated human saliva, and promising recoveries were obtained. The cost advantages of the printing technique, short timescale of the measurements, long storage stability and ease of use are attractive properties of the new mouthguard sensor. This non-invasive oral sensor for salivary N€(Carboxymethyl)lysine monitoring could potentially provide useful real-time information regarding a wearer's health condition, and thus, it holds considerable promise for the improved management of chronic diseases. [ABSTRACT FROM AUTHOR]

Abstract The threats posed by current and future changes in land use and climate have recently stressed the importance of evaluating the efficiency of present conservation measures that seek to restore or protect the naturalness of the wooded landscape. In Romania, the remaining old-growth forests in national parks have been consistently degraded by commercial logging and inappropriate forestry practices. This study provides an 8800 cal BP old history of compositional changes and disturbance regimes (natural and human induced) recorded in the old-growth Picea abies forests and P. abies – Fagus sylvatica – Abies alba mixed forests from the Rodna Mountains National Park. Our results reveal moderate turnover between 8800 and 5000 cal BP when vegetation dynamics were marked by the expansion of a closed P. abies forest and moderate disturbance intensity. The most stable compositional changes were recorded between 5000 and 1750 cal BP, primarily associated with the expansion of F. sylvatica and a low disturbance regime. The last 1750 years, but in particular over the last 50 years, correspond to the highest degree of turnover as a response to increased anthropogenic disturbance. This led to the reduced extent of the old-growth forest and extension of secondary forest (Pinus , Betula , Corylus avellana and Alnus glutinosa). This pollen based reconstruction of major forest cover loss over the last fifty years is also depicted in modern satellite imagery. Our long-term record indicates that the conservation status of the forests in this region is not efficiently implemented and in the future we may lose large tracts of the remaining old-growth forests. Highlights • Landscape stability concurs with the expansion of late successional species • High turnover along increased proportion of tree species with fast life strategies • Human impact has led to increased forest loss and compositional instability • Pollen evidence consistent with satellite imagery of old-growth forest loss [ABSTRACT FROM AUTHOR]

Although our understanding of key drivers of fire activity (climate, vegetation and humans) has improved, considerable uncertainty remains regarding the relative importance of these drivers and how they vary across spatial and temporal scales. Notably missing from our use of sedimentary charcoal records as a way to reconstruct past fire activity is the role of local controls on burning, and the relationships between different charcoal sizes, source area and types of depositional environment. To address these issues, we used seven sedimentary charcoal records within a small climatically homogenous area, but with heterogeneous vegetation and human history in the Eastern Romanian Carpathians. On a temporal scale, we found more homogenous fire histories during the early and mid Holocene (11,000–6000 cal yr BP), which became more heterogeneous thereafter. This suggests that climate exerted a stronger influence on fire activity during the early Holocene, whereas local controls (vegetation type and load, land cover and -use) became more important over the mid and late Holocene. On an elevation gradient, we found discrepancies in trends in fire activity between the coniferous forest, treeline and subalpine vegetation that could have resulted from variability in fuel availability in response to changes in the elevational climate gradient and degree of anthropogenic impact. For the coniferous forests, anthropogenic activities enhanced biomass burning from ca 2000–1500 cal yr BP through the use of fire to open up the forests. For the treeline – subalpine areas, humans enhanced fire activity earlier, i.e., from 8000 to 4500 cal yr BP, and reduced burning activity through clearance and hence decrease in fuel load, from ca. 3000 cal yr BP. Our determination of macro-charcoal size-classes show that the 150–300 μm fraction is present in the highest proportion at all sites, with most of this fraction perhaps connected to a combination of local and regional fires, and not strictly to local fire activity. Lakes provide higher charcoal influx and larger sizes of charcoal particles than peat, and this suggests that peat - lake sediment lithological transitions within the same record can contribute to a taphonomic change in apparent rates of charcoal deposition. [ABSTRACT FROM AUTHOR]

Objective Previous studies have shown a possible link between cardiovascular disease (CVD) and suicidal ideation (SI). However, limited information exists regarding the association between different subtypes of CVD and SI and the role of depression. Methods Data were used from the National Health and Nutrition Examination Survey for cycles 2009–2010 and 2011–2012. SI was assessed by item 9 of the Patient Health Questionnaire 9. Data regarding sociodemographic factors, and comorbid conditions were collected and examined as potential correlates. Logistic regression analyses were used to examine the relationship between CVD and subtypes and suicidal ideation. Results Among a total of 11,678 participants, suicidal ideation was significantly higher among patients with CVD compared to participants without a history of CVD (5.4% vs 3.6%, P < 0.001). A subset of patients with CVD with a history of congestive heart failure (CHF) and prior myocardial infarction (MI) had the highest percentage of SI (10.6%). The association between CVD and SI remained significant after adjusting for baseline characteristics and associated comorbidities including depression (OR 1.40, 95% CI 1.10–2.09, P = 0.006). Conclusion CVD is an independent risk factor for SI. The identification of a subset of patients with CVD at greatest risk of SI underlines the importance of screening in this vulnerable population. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-proxy study on the long-term development of mountain bog and forest in Central Europe. • Self-recovery of the peat formation process began at ca. 200 cal BP. • The impact of dust deposition led to changes in local plant succession. • Shallow water table depths (<10 cm below the surface) may not be necessary for restoration efforts. • Fagus sylvatica was replaced by Picea abies and Pinus sylvestris during the last two centuries. Peatlands are a significant landscape component in temperate mountain ranges and serve multiple functions. However, many peatlands were damaged, altered, or drained over the past centuries, and knowledge about their development is needed for their protection and sustainable management. In our study, we analysed two peat cores from a bog site located in the Black Forest (Southwest Germany) using high-resolution multi-proxy palaeoecological analysis, including biological indicators (plant macrofossils, pollen, testate amoebae), macro-and micro-charcoal as well as geochemical analyses (peat stoichiometry and stable isotopes (δ13C , δ15N)) supported by radiocarbon dating. We tracked the development of the peatland and forest ecosystem to (i) determine their current ecological state, and to (ii) assess the role of different agents of change at the catchment scale on peatland development. The overall objective was to determine natural reference conditions as a basis for the restoration of degraded mountain bogs in the Black Forest Mountains and other temperate mountain ranges. Our results revealed that: i) the bog developed on mineral bedrock of slight slope through paludification around ca. 10,000 cal. BP; ii) the pristine plant populations dominated by Sphagnum fuscum occurring from 6200 cal. BP were replaced by Sphagnum medium/divinum and Eriophorum vaginatum since ca. 3300 cal. BP, most likely due to hydrological disturbances and possible dust deposition on the bog; iii) peat formation at the study site seems still active despite relatively deep water levels (ca. 22–26 cm below surface) and was active over the last 8000 years also when WTD varied between 12 and 26 cm; iv) the self-recovery of peat formation at this mountain bog is possible; v) the protection and restoration of mountain bog ecosystems should also consider land cover changes in the surrounding catchment, serving as further indicators or drivers of mountain bog development. [ABSTRACT FROM AUTHOR]