Search

Analysis of phytoliths (plant silica bodies) still may have an unrevealed potential in paleoenvironmental reconstruction studies. This can provide novel findings in research on environmental change as phytoliths play an important role in the silicon biogeochemical cycle. In favorable environmental conditions, Picea abies [L.] H. Karst (Norway spruce) needles develop a phytolith layer consisting of more or less cubical or cuboid (blocky) phytoliths in their transfusion tissue that becomes continuous toward the apex of the needle. This can be studied in situ in fossil (subfossil) needles under a stereomicroscope. This study reports the blocky-type phytolith preservation in fossil spruce needles in sediment sections of the lake Černé jezero (Bohemian Forest, Czech Republic). The oldest needle containing phytoliths was 7.8 cal ka BP. Despite differences in the Energy Dispersive X-ray (EDX) spectra of different age phytoliths, the studied subfossil phytoliths did not lose their globular ultrastructure in the needle tissue, proving the stability of this phytolith morphotype. As the tissue of the needle fossils can preserve phytoliths in situ, further micro-analytical measurements will make these needles promising tools for paleoenvironmental reconstructions. The most favorable period for spruce phytolith formation for the studied region appears to be the period 6.0–4.5 cal ka BP, within the Holocene Climate Optimum period. In order to use these phytoliths as a terrestrial climate proxy, the next step is to refine their sensitivity to environmental changes.

Some species of two tribes (Anthidiini and Osmiini) of the bee family Megachilidae utilize empty gastropod shells as nesting cavities. While snail-nesting Osmiini have been more frequently studied and the nesting biology of several species is well-known, much less is known about the habits of snail-nesting Anthidiini. We collected nests of four species of the genusRhodanthidium(R. septemdentatum,R. sticticum,R. siculumandR. infuscatum) in the Czech Republic, Slovakia, Catalonia (Spain) and Sicily (Italy). We dissected these nests in the laboratory and documented their structure, pollen sources and nest associates. The four species usually choose large snail shells. All four species close their nests with a plug made of resin, sand and fragments of snail shells. However, nests of the four species can be distinguished based on the presence (R. septemdentatum,R. sticticum) or absence (R. siculum,R. infuscatum) of mineral and plant debris in the vestibular space, and the presence (R. septemdentatum,R. infuscatum) or absence (R. sticticum,R. siculum) of a resin partition between the vestibular space and the brood cell.Rhodanthidium septemdentatum,R. sticticumandR. siculumusually build a single brood cell per nest, but allR. infuscatumnests studied contained two or more cells. For three of the species (R. siculum,R. septemdentatumandR. sticticum) we confirmed overwintering in the adult stage. Contrary toR. siculum,R. septemdentatumandR. sticticumdo not hide their nest shells and usually use shells under the stones or hidden in crevices within stone walls. Nest associates were very infrequent. We only found twoR. sticticumnests parasitized by the chrysidid waspChrysura refulgensand seven nests infested with pollen mites Chaetodactylus cf. anthidii. Our pollen analyses confirm thatRhodanthidiumare polylectic but show a preference for Fabaceae byR. sticticum.

The pace of Holocene vegetation change Although much is known about the rapid environmental changes that have occurred since the Industrial Revolution, the patterns of change over the preceding millennia have been only patchily understood. Using a global set of >1100 fossil pollen records, Mottl et al. explored the rates of vegetation change over the past 18,000 years (see the Perspective by Overpeck and Breshears). The authors show that the rates of change accelerated markedly during the Late Holocene (∼4.6 to 2.9 thousand years ago), even more rapidly than the climate-driven vegetation changes associated with the end of the last glacial period. In addition, the Late Holocene acceleration began for terrestrial communities as a whole, suggesting that the acceleration in turnover over the past two centuries is the tip of a deeper trend. Science , abg1685, this issue p. 860 ; see also abi9902, p. 786

Water brownification has long altered freshwater ecosystems across the northern hemisphere. The intensive surface water brownification of the last 30 years was however preceded by previous long-lasting more humic browning episodes in many catchments. To disentangle a cascade of browning-induced environmental stressors this longer temporal perspective is essential and can be reconstructed using paleolimnological investigations. Here we present a Holocene duration multi-proxy paleolimnological record from a small forest mountain lake in the Bohemian Forest (Czechia) and show that climate-related soil saturation and peatland development has driven surface water brownification for millennia there. A long core retrieved from the central part of the lake was dated using

Aim Pollen has been used before to reconstruct Holocene plant diversity changes in broadly delimited regions such as continents and countries. In this study we ask whether finer-scale differences in plant diversity, which are of interest to biogeographers and ecologists, are also detectable in the fossil pollen record coming from a single, biogeographically complex region of temperate Europe. Location Central Europe (Czech Republic, Slovakia). Taxon Vascular plants. Methods Fossil pollen extracted from 18 high-quality profiles was used as a proxy of past plant diversity. Pollen counts of tree taxa were corrected by pollen productivities and pollen assemblages were resampled to 100 grains per sample and 150 grains per 500-year time window. SiZer analysis was used to test and visualize multi-scale diversity patterns. SiZer maps were compared using principal coordinate analysis, and linear modelling was used to identify the best predictors. Pollen composition was analysed using non-metric multidimensional scaling. K-means clustering and indicator species analysis were used to interpret ordination results. Results Mean Holocene plant diversity is significantly predicted by latitude, whilst its temporal pattern varies by biogeographical region. Major differences were found between the Mesic and Montane Hercynia (relatively low diversity, increasing only in the Late Holocene) and Pannonia, the Carpathians and the Warm Hercynia (higher diversity, increasing from the Early or Middle Holocene onwards). The low diversity in the Middle and Late Holocene is associated with the prevalence of woody and acidophilic taxa. High diversity is associated with numerous grassland and minerotrophic wetland taxa, crops and weeds. Main conclusions Plant diversity and its changes during the Holocene are geographically structured across temperate Europe. The main causes appear to be differences between biogeographical regions in the dynamics of landscape openness and vegetation composition. The differences reflect spatial patterns in climate and human impact and their temporal changes.

In this study we aim to investigate millennial-scale dynamics of Isoëtes, a type of macrophyte well adapted to oligotrophic and clear-water lakes. Despite its wide distribution during the Early Holocene, nowadays Isoëtes is considered as vulnerable or critically endangered in many Central European countries. Using a multi-proxy palaeoecological reconstruction involving Isoëtes micro- and megaspores, pollen, plant macrofossils, macro-charcoal, diatoms and chironomids from four lakes (Prášilské jezero, Plešné jezero, Černé jezero, Rachelsee) located in the Bohemian Forest Ecosystem mountain region in Central Europe, we reconstruct Isoëtes dynamics and discuss how local environmental factors impacted its distribution and abundance during the Holocene. Our results show regionally concurrent patterns of Isoëtes colonisation across all lakes beginning 10,300–9300 cal yr BP, and substantially declining around 6400 cal yr BP. Results from Prášilské jezero imply that Isoëtes decline and collapse in this lake reflect gradual dystrophication that led to the browning of lake water. This is evidenced by a shift in diatom assemblages towards more acidophilous taxa dominated by Asterionella ralfsii and by a decrease in total chironomid abundance and taxa sensitive to low oxygen levels. Dystrophication of Prášilské jezero was linked with the immigration of the late-successional tree taxa ( Picea abies and later Fagus sylvatica and Abies alba), peatland expansion, and decreasing fire activity. Multi-site comparison of pollen records suggest that these vegetation-related environmental changes were common for the whole region. Our study demonstrates the sensitivity of Isoëtes to millennial-scale natural environmental changes within the surrounding lake catchment.

Temperate mountain forests have experienced an increase in frequency and severity of natural disturbances (e.g., droughts, fires, windstorms and insect outbreaks) in recent decades due to climate and environmental change. Outbreaks of bark beetles have caused significant dieback of conifer forests in Central Europe and it is essential to model and predict the potential severity of future bark beetle outbreaks. However, to predict future bark beetle activity, historical baseline information is required to contextualize the magnitude of current and potential future outbreaks. A fossil beetle record from a forest hollow in the Tatra Mountains, Slovakia; one of the best-preserved national parks in Central Europe, was produced to identify insect outbreaks during the last millennia. Sub-fossil bark beetle remains were compared with parallel pollen and charcoal to assess whether peaks in conifer bark beetle remains correspond with indications of disturbance documented in historical or sedimentary fossil records. Three peaks in bark beetle remains were detected (1) post-2004, (2) AD 1140–1440, and (3) AD 930–1030. The abundance of species Pityogenes chalcographus and Pityophthorus pityographus in the two top samples can be linked directly to large bark beetle outbreaks in the High Tatra Mountains after 2004. P. chalcographus and P. pityographus are also the abundant species in the second peak (AD 1140–1440) while the third peak (AD 930–1030) consists of the species Polygraphus poligraphus. The most prominent conifer bark beetle in Central Europe, Ips typographus, was found to be present in most of the samples but always at very low numbers. It is plausible that P. chalcographus and P. pityographus fossils might be useful proxies for past conifer bark beetle outbreaks in Central Europe, as they occur together with fossils of I. typographus but appear to be well-preserved. A significant correlation was found between primary bark beetles and macroscopic charcoal densities in the sediment, highlighting the complex interactions between disturbance agents, bark beetles and fire, in this long-term regime of natural disturbances. Our 1400-year disturbance record shows how bark beetle outbreaks have been an important component of the regional natural disturbance regime for over a millennium and have intensified with increasing anthropogenic activity. Bark beetle outbreaks are likely one of the drivers promoting the future ecological stability of the temperate conifer ecosystem over decades to centuries.

Understanding pollen-vegetation relationships is crucial for accurate land-cover and climate reconstructions, yet important parameters for quantifying past vegetation abundance are mostly unknown for large parts of Europe harbouring temperate thermophilous ecosystems. We collected pollen and vegetation data in central-eastern Europe, a region covered by patchy cultural landscapes of high biodiversity to estimate relative pollen productivity (RPP) for important pollen-equivalent taxa. Our study area was situated in the south-western part of the White Carpathians (Czechia–Slovakia borderland), where we collected 40 modern moss pollen samples scattered over 250 km2 and mapped vegetation within 100 m around each pollen site. Additional vegetation data were compiled from Forest management plans, Natura 2000 habitat mapping and floristic inventories over the entire area. We calculated RPP (referenced to Poaceae) by testing two approaches: the extended R-value (ERV) model by estimating relevant source area of pollen and the REVEALS-based productivity using regional scale vegetation estimates. Two models were applied to depict pollen dispersal: Lagrangian stochastic and the Gaussian plume (Prentice) models. We estimated RPP for 16 taxa using the ERV model and an additional nine taxa using REVEALS. Both approaches found Plantago lanceolata-type to be a high pollen producer, Quercus medium-to-high, Asteraceae subf. Cichorioideae, Anthemis-type, Ranunculus acris-type and Rubiaceae low-to-medium and Brassicaceae and Senecio-type as low pollen producers. Results for other, mainly tree taxa, significantly differed in both approaches mainly due to largely uneven representation in both local and regional vegetation. In comparison with other studies, our data demonstrate a high variability in the estimated RPPs which could be influenced by climatic conditions or potentially vegetation structure. We suggest that the accuracy of RPP estimates could be enhanced by comparing modern pollen data with large-scale vegetation data in the future.

Long-term perspectives on disturbance dynamics are important for the conservation of protected areas, yet restoration and conservation strategies in the Bohemian-Bavarian Forest Mountains do not consider the long-term role and patterns of forest fire, which is still deemed a negligible ecosystem disturbance in Central Europe. The scarcity of macroscopic charcoal studies in this area has likely hampered a complete understanding of local fire regime dynamics and its legacies in the present forest structure and composition. Here we used macroscopic charcoal (number, area and morphology of charred particles) and pollen analysis to investigate high resolution spatial and temporal patterns in Holocene fire regimes in the Bavarian-Bohemian Forest. We explored the relationship between changing forest composition dynamics and the influence topography had on spatial patterns of biomass burning. For this, we selected three lacustrine sites (two new, one published), located along a 30 km longitudinal transect within the studied area, at similar elevations in the mixed forest belt, with opposite (north vs. south) aspects. Results showed similar changes in biomass burning, fire frequency and peak magnitude at all sites, with a maximum during the early Holocene when fire resistant taxa (Pinus and Betula) dominated. Fire frequency decreased by half with the expansion of more fire-sensitive taxa (e.g., Picea and Fagus) during the mid-Holocene and reached a second maximum in the late Holocene, parallel with sustained increases in anthropogenic pollen indicators. We found a close north-south correspondence in the succession of fire patterns, i.e., fine-scale changes in biomass burning in the Bavarian Forest site (south-facing catchment) occurred around the same time with those observed at the Bohemian Forest sites (predominantly north-facing catchments), and these changes mirrored the Holocene dynamics of the main forest taxa. For example, the lowest biomass burning and peak magnitude intervals marked the beginning of Picea abies expansion at ~ 9 ka BP, Fagus sylvatica expansion at ~6 ka and Abies alba expansion at ~5 ka BP. Furthermore, we found a direct relationship between the abundance of charred morphotypes of conifer needles and deciduous leaves and the dominance of pine and birch in our pollen records, and a close correspondence between the abundance of non-woody charcoal morphotypes and pollen-derived landscape openness. Non-woody charcoal morphotypes dominated the charcoal records in the Early Holocene at the peak of biomass burning, whereas the abundance of woody morphotypes peaked around 6-8 ka BP and over the last millennium and their proportion in total charcoal influx increased starting 4 ka BP. Our study enables a better understanding of past and present fire regimes in the Bavarian-Bohemian Forest Mountains and highlights the need to consider the effects of fire as part of climate-change forest conservation strategies.

To distinguish human-caused from naturally-caused fire regimes, palaeoecological records must demonstrate that observed changes in vegetation and fire are in response to changes in human activity rather than driven by natural climate-fire relationships. Here, we use a high-resolution multi-proxy approach (testate amoebae derived depth to water table (DWT), macro- and micro-charcoal, charcoal morphologies, pollen, non-pollen palynomorphs, plant macrofossils, and XRF) from Pékna, a mid-elevation peat bog situated near Lipno Reservoir - an area rich in human land use - to investigate human-driven vs. naturally-driven fire regimes in the Šumava Mountains. Our results span the entire Holocene and illustrate that humans have been consistently modifying the landscape since 5,500 cal yr BP. Specifically, during the mid-Holocene (7,000 – 4,000 cal yr BP) when water table was at its highest at Pékna, relatively frequent, low-severity fires occurred and was accompanied by the prolonged presence of coprophilous fungi, secondary human indicators and an opening of the forest, suggesting human activities. Human land use intensified ~1,500 cal yr BP as indicated by increases in primary human indicator species, an increase in early successional tree species (Pinus and Betula) indicating an opening of the forest canopy, and the development of regional mining is suggested by a marked increase in the concentration of lead (Pb). While water table depths decreased indicating drier conditions ~1,500 cal yr BP, local fires persisted, burning at low severities as indicated by the continued presence of charred herb macrofossils. The most intensive land use occurred in the last 500 years with the highest abundance of primary and secondary human indicator species, and coprophilious fungi. Locally, marked increases in the concentration of both redox-sensitive elements such as iron (Fe), calcium (Ca), sulphur (S), and chlorine (Cl), and detrital elements such as potassium (K), aluminum (Al) and Titanium (Ti) indicate major changes in the depositional environment over the last 500 years, possibly due to peat draining. However, this time period witnessed decreased biomass burning as a result of a more open landscape and less fuels to burn. These results contribute to a growing body of literature illustrating the importance of prehistoric impact in the mid-mountains of Central Europe.

Disentangling the long-term changes in forest disturbance dynamics provides a basis for predicting the forest responses to changing environmental conditions. The combination of multidisciplinary records can offer more robust reconstructions of past forest disturbance dynamics. Here we link disturbance histories of the central European mountain spruce forest obtained from dendrochronological and palaeoecological records (fossil pollen, sedimentary charcoal, bark beetle remains and geochemistry) using a small glacial lake and the surrounding forest in the Sumava National Park (Czech Republic). Dendrochronological reconstructions of disturbance were created for 300-year-long records from 6 study plots with a minimum of 35 trees analyzed for the abrupt growth increases (releases) and rapid early growth rates, both indicative of disturbance events. High-resolution analysis of lake sediments were used to reconstruct 800-year long changes in forest composition and landscape openness (fossil pollen), past fire events (micro- and macroscopic charcoal), bark beetle occurrence (fossil bark beetle remains), and erosion episodes (geochemical signals in the sediment) potentially resulting from disturbance events. Tree-ring data indicate that disturbances occurred regularly through the last three centuries and identify a most intensive period of disturbances between 1780 and 1830 CE. Geochemical erosion markers (e.g. K, Zr, % inorganic) show greater flux of catchment sediment and soils in the periods 1250–1400 and 1450–1500 CE, before a substantial shift to a more erosive regime 1600–1850 and 1900 CE onwards. Pollen records demonstrate relatively small changes in forest composition during the last 800 years until the beginning of the 20th century, when there was decrease in Picea. Fossil bark beetle remains indicate continuous presence of bark beetles from 1620s to 1800s, and charcoal records suggest that more frequent fires occurred during the 18th century. Each of the dendrochronological, palaeoecological and sedimentological records provide a unique perspective on forest disturbance dynamics, and combined offer a more robust and complete record of disturbance history. We demonstrate that sedimentary proxies originating from the lake catchment mirror the forest disturbance dynamics recorded in the tree-rings. The multidisciplinary records likely record forest disturbances at different spatial and temporal scales revealing different disturbance characteristics. Integrating these multidisciplinary datasets demonstrates a promising way to obtain more complete understanding of long-term disturbance dynamics. However, integrating datasets with variable spatial and temporal influence remains challenging. Our results indicated that multiple disturbance factors, such as windstorms, bark beetle outbeaks and fires, may occur simultaneously creating a complex disturbance regime in mountain forests, which should be considered in forest management and conservation strategies.

Montane biomes are niche environments high in biodiversity with a variety of habitats. Often isolated, these non-continuous remnant ecosystems inhabit narrow ecological zones putting them under threat from changing climatic conditions and anthropogenic pressure. Twelve sediment cores were retrieved from a peat bog in Tatra National Park, Slovakia, and correlated to each other by wiggle-matching geochemical signals derived from micro-XRF scanning, to make a reconstruction of past conditions. A fossil beetle (Coleoptera) record, covering the last 1000 years at 50- to 100-year resolution, gives a new insight into changing flora and fauna in this region. Our findings reveal a diverse beetle community with varied ecological groups inhabiting a range of forest, meadow and synanthropic habitats. Changes in the beetle community were related to changes in the landscape, driven by anthropogenic activities. The first clear evidence for human activity in the area occurs c. 1250 CE and coincides with the arrival of beetle species living on the dung of domesticated animals (e.g. Aphodius spp.). From 1500 CE, human (re)settlement, and activities such as pasturing and charcoal burning, appear to have had a pronounced effect on the beetle community. Local beetle diversity declined steadily towards the present day, likely due to an infilling of the forest hollow leading to a decrease in moisture level. We conclude that beetle communities are directly affected by anthropogenic intensity and land-use change. When aiming to preserve or restore natural forest conditions, recording their past changes in diversity can help guide conservation and restoration. In doing so, it is important to look back beyond the time of significant human impact, and for this, information contained in paleoecological records is irreplaceable.

AimsReconstruction of the Holocene diversity changes in a biogeographically complex region. Description of major diversity patterns, testing their predictors, and their interpretation in the palaeoecological and biogeographical context. Testing the assumption that pollen record is informative with respect to plant diversity in our study area.MethodsFossil pollen extracted from 18 high-quality profiles was used as a proxy of past plant diversity. Pollen counts of tree taxa were corrected by pollen productivity, and pollen assemblages were resampled to 100 grains per sample and 150 grains per 500-years time window. SiZer analysis was used to test and visualize multi-scale diversity patterns. Linear modelling was used to identify the best predictors. SiZer maps and pollen composition were analysed using non-metric multidimensional scaling. K-means clustering and indicator species analysis were used to interpret ordination results.ResultsMean Holocene plant diversity is significantly predicted by latitude, while its temporal pattern followed the biogeographical region and elevation. Major differences were found between the Mesic and Montane Hercynia (lower diversity, increasing only in the Late Holocene) and Pannonia, the Carpathians and Warm Hercynia (higher diversity, increasing from the Early or Middle Holocene on). Low diversity in the Middle and Late Holocene is associated with the prevalence of woody and acidophilic taxa. High diversity is associated with numerous grassland and minerotrophic wetland taxa, crops and weeds. Fossil-modern pollen diversity and modern pollen-plant diversity show significant positive relationships.ConclusionsPlant diversity and its changes during the Holocene are geographically structured across temperate Europe. Main causes appear to be differences in past dynamics of the landscape openness and vegetation composition, driven mainly by changes in climate and human impact and their different timing. Fossil pollen, if appropriately treated, is a useful proxy of past plant diversity.

Pollen is an abundant fossil and the most common proxy for plant diversity during the Holocene. Based on datasets in open, forest, and mixed habitats, we used the spatial distribution of floristic diversity to estimate the source area of pollen diversity and identify factors influencing the significance of this relationship.Our study areas are Bohemian-Moravian Highlands and White Carpathians (the Czech Republic and the Slovak Republic).Sampling 60 sites in forest and open habitats in two study regions with contrasting floristic diversity, we calculated taxonomic richness (alpha diversity) and total spatial variance (beta diversity) for pollen and floristic data along two transects, each 1 km long. Following this, we calculated the correlation between floristic and pollen diversity. We also assessed the consistency of the relationship in different habitats. Finally, we regressed local contributions of individual sites to the beta diversity of pollen and floristic data in each of the regions.There was a positive correlation between pollen and floristic richness in both habitats in both regions; open and mixed datasets were significant. The highest correlation (adjusted R2) mostly occurred within the first tens of metres (1.5–70) and then within the first hundreds of metres (250–550). Variances of pollen data significantly correlated with variances of floristic data between 100 and 250 m. Local contributions to beta diversity of pollen and plants significantly correlated in the forest and one of the mixed datasets.Floristic richness at the pollen site and position of the site within the landscape structure determine the sequence of the appearing species in the increasing distance. The number of species sets the source area of pollen richness and dissimilarity of appearing species controls the source area of pollen variance. These findings, linking pollen and floristic diversity, provide an essential stepping-stone for the reconstruction of historic plant diversity.

Over the past few decades, mean summer temperatures within the Carpathian Mountains have increased by as much as 2 °C leading to a projected increased forest fire risk. Currently, there are no paleofire records from the Western Carpathians that provide the long-term range of natural variability to contextualise the response of upper-montane forests to future environmental change and disturbance regimes. We present the first high-resolution Holocene fire history record from the upper-montane ecotone from the High Tatra Mountains, Slovakia, as well as provide a regional synthesis of pan-Carpathian drivers of biomass burning in upper-montane forests. Our results illustrate that forest composition and density both greatly influence biomass burning, creating two different climate-fuel feedbacks. First, warmer conditions in the early Holocene, coupled with generally higher abundances of Pinus sp., either P. cembra and/or P. mugo/sylvestris, created a positive climate-fuel relationship that resulted in higher amounts of biomass burning. Second, cooler and wetter late Holocene conditions led to denser Picea abies upper-montane forests, creating a negative climate-fuel feedback that reduced biomass burning in upper-montane forests across the Carpathians. Given that warmer and drier conditions are expected across the entire Carpathian region in the future, our results illustrate how future climate change could potentially create a positive climate-fuel relationship within upper-montane forests dominated by Picea abies and Pinus cembra and/or P. mugo/sylvestris.

Disturbances such as fires and grazing have major impacts on biodiversity. While it has been suggested that species richness is highest with intermediate levels of disturbance, currently there is no consensus due to an absence of data covering large temporal and spatial scales. We developed a new method to examine disturbance‐diversity relationships (DDR) using sedimentary pollen data linked with species’ disturbance ecology. We reconstructed disturbance and diversity dynamics in the region of the European temperate zone over the last 12,000 years and calculated DDR for 900‐year sequential temporal windows. Disturbance frequency was highest in the early and late Holocene, while remaining low in the mid‐Holocene. Diversity increased continuously from the start of the Holocene. Our results demonstrate that over the past 12,000 years DDR changed from hump‐shaped into monotonic increasing pattern. While both highly disturbed and undisturbed sites were strongly impoverished in the early Holocene, as species migrated, biodiversity levels have subsequently affected disturbance regimes with highly disturbed sites now being the highest in species richness. Synthesis. Land‐use changes in the last 4,000 years created an increasingly patchy landscape, allowing invasive species adapted to high‐frequency disturbance to migrate across the landscape. The link between high diversity and disturbed areas is relatively recent and may anticipate even greater disturbance frequencies in future. Our findings also support a hypothesis that species migration, and the structure of the species pool critically determines the response of biota to external factors such as disturbance.

International audience; The European Pollen Database (EPD) is a community effort to archive and make available pollen sequences from across the European continent. Pollen sequences provide records that may be used to infer past vegetation and vegetation change. We present here maps based on 828 sites from the EPD giving an overview of changes in postglacial pollen assemblages in Europe over the past 15,000 years. The maps show the distribution and abundance of 54 different pollen taxa at 500 year intervals, supported by new age-depth models and associated chronological uncertainty analysis. Results show the individualistic patterns of spread of different pollen taxa, and provide a standardized dataset for further analysis, defining a spatial context for the study of past plant and vegetation changes and other aspects of environmental history in Europe.

Multiproxy palaeoecological evidence from a sandstone region in northern Czech Republic was collected to explore the impact of fire disturbances on the decline of the broadleaved forests during the Late Bronze Age (3250–3050 cal. BP). It has been hypothesized that human-accelerated soil leaching affected the nutrient availability in the sandstone area, thus promoting the expansion of oligotrophic-adapted plant communities in the late-Holocene. Little is known about the mechanisms which induced such large-scale vegetation transformation. We sought to determine which driving forces were involved using independent proxy records – soil and sedimentary charcoal, pollen and fungal spores. Local fire history was derived from the variation in charcoal accumulation rates (CHAR) preserved in Eustach peatbog. The fire frequency (FF) estimation over the past ~7500 years revealed distinct phases of increased burning between 3100 and 2120 cal. BP (3.0 fires 1000 yr−1) and 1400–600 cal. BP (4.3 fires 1000 yr−1). Rapid c...

Investigating past changes in temperate mountain spruce forest ecosystems and the processes behind them can provide valuable information for understanding present and future ecosystem dynamics. To assess the late Holocene ecosystem change and disturbance history in mountain spruce forests, we sampled four small forest hollows from the High Tatra mountains in Slovakia. We use pollen analysis to reconstruct changes in forest composition over the last circa 5000 cal. yr BP. Fire history is analysed using macroscopic charcoal counts and charcoal area measurements. As disturbance is one of the key factors shaping mountain forest dynamics, the analysed pollen records will be processed with a new method quantifying disturbance based on plant ecological indices (Kuneš et al. 2019). These indices for disturbance will be attributed to pollen taxa and then disturbance frequency and severity for the whole community will be calculated. We assess the role of climate and human impact as potential drivers on the past forest and disturbance dynamics. The climate variable will be constructed from modelled climate data for the last 4000 years and for the past 1000 years we will use climate reconstruction from the tree-ring records from the region. We use human indicator pollen taxa as the variable for human influence on ecosystem dynamics, and to indicate human activity in the region.Preliminary results demonstrate opening of the landscape circa 800-500 cal. yr BP in connection with a change in the disturbance regime as indicated by the disturbance indices. The presence of human indicator pollen taxa in all small hollow records suggest landscape opening in connection with anthropogenic activity in the region. In addition, the charcoal records demonstrate periods of fire, which coincide with the opening of landscape and it is plausible that change in the fire regime is connected to the intensified human activity in the region. These results will be discussed further in the presentation in the light of climate data and further data analysis.Reference:Kuneš, P. Abraham, V. & Herben, T. 2019. Changing disturbance-diversity relationships in temperate ecosystems over the past 12 000 years. Journal of Ecology 107:1678–1688.

International audience; The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes compared to the Holocene. Here, we assemble 47 carefully selected Eemian pollen sequences from Europe to explore geographical patterns of (1) total compositional turnover and total variation for each sequence and (2) stratigraphical turnover between samples within each sequence using detrended canonical correspondence analysis, multivariate regression trees, and principal curves. Our synthesis shows that turnover and variation are highest in central Europe (47-55°N), low in southern Europe (south of 45°N), and lowest in the north (above 60°N). These results provide a basis for developing hypotheses about causes of vegetation change during the Eemian and their possible drivers.

Reconstructing past vegetation abundance and land-cover changes through time has important implications in land management and climate modelling. To date palaeovegetation reconstructions in Australia have been limited to qualitative or semi-quantitative inferences from pollen data. Testing pollen dispersal models constitutes a crucial step in developing quantitative past vegetation and land cover reconstructions. Thus far, the application of quantitative pollen dispersal models has been restricted to regions dominated by wind-pollinated plants (e.g. Europe) and their performance in a landscape dominated by animal-pollinated plant taxa is still unexplored. Here we test, for the first time in Australia, two well-known pollen dispersal models to assess their performance in the wind- and animal-pollinated vegetation mosaics of western Tasmania. We focus on a mix of wind- (6 taxa) and animal- (7 taxa) pollinated species that comprise the most common pollen types and key representatives of the dominant vegetation formations. Pollen Productivity Estimates and Relevant Source Area of Pollen obtained using Lagrangian Stochastic turbulent simulations appear to be more realistic when compared to the results from the widely used Gaussian Plume Model.

Forests cover approximately one-third of Central Europe. Oak (Quercus) and European beech (Fagus sylvatica) are considered the natural dominants at low and middle elevations, respectively. Many coniferous forests (especially of Picea abies) occur primarily at midelevations, but these are thought to have resulted from forestry plantations planted over the past 200 years. Nature conservation and forestry policy seek to promote broadleaved trees over conifers. However, there are discrepancies between conservation guidelines (included in Natura 2000) and historical and palaeoecological data with regard to the distribution of conifers. Our aim was to bring new evidence to the debate on the conservation of conifers versus broadleaved trees at midelevations in Central Europe. We created a vegetation and land-cover model based on pollen data for a highland area of 11,300 km2 in the Czech Republic and assessed tree species composition in the forests before the onset of modern forestry based on 18th-century archival sources. Conifers dominated the study region throughout the entire Holocene (approximately 40-60% of the area). Broadleaved trees were present in a much smaller area than envisaged by current ideas of natural vegetation. Rather than casting doubt on the principles of Central European nature conservation in general, our results highlight the necessity of detailed regional investigations and the importance of historical data in challenging established notions on the natural distribution of tree species.

Wildfire occurrence is influenced by climate, vegetation and human activities. A key challenge for understanding fire-climate-vegetation interactions is to quantify the effect vegetation has in mediating fire regime. Here, we explore the relative importance of Holocene land cover and dominant functional forest type, and climate dynamics on biomass burned in temperate and boreo-nemoral regions of Central and Eastern Europe over the past 12 ka BP years. We used an extensive data set of Holocene pollen and sedimentary charcoal records, in combination with climate simulations and novel statistical modelling. Biomass burned was highest during the early Holocene and lowest during the mid Holocene in all three ecoregions, but diverged more markedly over the past 3–4 ka BP. Although the climate was an important driver of fire hazard during the warm and dry early Holocene, tree cover was consistently the strongest predictor of past biomass burning. In temperate forests, biomass burned was high at ~ 45 % tree cover and decreased strongly towards 60 % tree cover. In needleleaf dominated forests, biomass burned was highest at ~ 60–65 % tree cover and abruptly declined at > 65 % tree cover. Biomass burned also increased when arable lands and grasslands reached ~ 15–20 %, although this relationship was highly dynamic depending on land use intensity throughout ignition and fuel type and availability. Our observations cover the full range of Holocene climate variability and land cover changes and illustrates that percentages of land cover is a key predictor of the probability of fire occurrence over timescales of centuries to millennia. We suggest that long-term fire risk may be effectively reduced through land cover management, given that land cover has controlled fire regimes under the dynamic climates of the Holocene.

The population boom-and-bust during the European Neolithic (7000–2000 BC) has been the subject of lively discussion for the past decade. Most of the research on this topic was carried out with help of summed radiocarbon probability distributions. We aim to reconstruct population dynamics within the catchment of a medium sized lake on the basis of information on the presence of all known past human activities. We calculated a human activity model based on Monte Carlo simulations. The model showed the lowest level of human activity between 4000 and 3000 BC. For a better understanding of long-term socio-environmental dynamics, we also used the results of a pollen-based quantitative vegetation model, as well as a local macrophysical climate model. The beginning of the decline of archaeologically visible human activities corresponds with climatic changes and an increase in secondary forest taxa probably indicating more extensive land use. In addition, social and technological innovations are important, such as the introduction of the ard, wheel, animal traction and metallurgy, as well as changes in social hierarchy characterizing the same period.

This study investigated the long-term role and drivers of fire in the central European temperate spruce-beech forests from Prášilské jezero, Czech Republic. The results illustrate the complex relationship between broad-scale climate, vegetation composition, and local human activities on fire throughout the Holocene. Biomass burning was the highest (average 3 fires/1000 years) and most severe during the early Holocene when fire resistant taxa (Pinus, Corylus and Betula) dominated. Using a Generalized Additive Model to assess the response of dominant canopy taxa to changes in biomass burning and fire severity, response curves demonstrate a positive relationship (p < 0.01) between fire resistant taxa and increases in biomass burning. Norway spruce (Picea abies) established ∼10,000 cal yr BP and expanded during peak biomass burning. Response curves show a slight negative relationship with Picea and increasing biomass burning, and a positive relationship with increasing fire severity. This suggests that central European spruce forests may not be significantly impacted by fire. Regional biomass burning dramatically decreased with the expansion of fire sensitive taxa (e.g. Fagus sylvatica) ∼6500 cal yr BP, yet no dramatic reduction in local fire frequency occurred. This suggests either human activities or rare fire-promoting climatic events were important in shaping local fire regimes. Fire activity peaked (6 fires/1000 years) ∼2500 cal yr BP and paralleled increases in anthropogenic pollen indicators. Fagus response curves illustrates a negative (p < 0.01) relationship with increasing biomass burning and fire severity suggesting that natural Fagus forests may be increasingly vulnerable to projected increases in wildfire occurrence. © 2018 Elsevier Ltd

The post-glacial fate of central European grasslands has stimulated palaeoecological debates for a century. Some argued for the continuous survival of open land, while others claimed that closed forest had developed during the Middle Holocene. The reasons behind stability or changes in the proportion of open land are also unclear. We aim to reconstruct regional vegetation openness and test the effects of climate and human impact on vegetation change throughout the Holocene. We present a newly dated pollen record from north-western fringes of the Pannonian Plain, east-central Europe, and reconstruct Holocene regional vegetation development by the REVEALS model for 27 pollen-equivalent taxa. Estimated vegetation is correlated in the same area with a human activity model based on all available archaeological information and a macrophysical climate model. The palaeovegetation record indicates the continuous presence of open land throughout the Holocene. Grasslands and open woodlands were probably maintained by local arid climatic conditions during the early Holocene delaying the spread of deciduous (oak) forests. Significantly detectable human-made landscape transformation started only after 2000 BC. Our analyses suggest that Neolithic people spread into a landscape that was already open. Humans probably contributed to the spread of oak, and influenced the dynamics of hazel and hornbeam.

Aim: To test competing hypotheses about the timing and extent of Holocene landscape opening using pollen-based quantitative land-cover estimates. Location: Dove Lake, Tasmanian Wilderness World Heritage Area, Australia. Methods: Fossil pollen data were incorporated into pollen dispersal models and corrected for differences in pollen productivity among key plant taxa. Mechanistic models (REVEALS-Regional Estimates of VEgetation Abundance from Large Sites) employing different models for pollen dispersal (Gaussian plume and Lagrangian stochastic models) were evaluated and applied in the Southern Hemisphere for the first time. Results: Validation of the REVEALS model with vegetation cover data suggests an overall better performance of the Lagrangian stochastic model. Regional land-cover estimates for forest and non-forest plant taxa show persistent landscape openness throughout the Holocene (average landscape openness similar to 50%). Gymnoschoenus sphaerocephalus, an indicator of moorland vegetation, shows higher values during the early Holocene (11.7-9 ka) and declines slightly through the mid-Holocene (9-4.5 ka) during a phase of partial landscape afforestation. Rain forest cover reduced (from similar to 40% to similar to 20%) during the period between 4.2-3.5 ka. Main conclusions: Pollen percentages severely under-represent landscape openness in western Tasmania and this bias has fostered an over-estimation of Holocene forest cover from pollen data. Treeless vegetation dominated Holocene landscapes of the Dove Lake area, allowing us to reject models of landscape evolution that invoke late-Holocene replacement of a rain forest-dominated landscape by moorland. Instead, we confirm a model of Late Pleistocene inheritance of open vegetation. Rapid forest decline occurred after c.4 ka, likely in response to regional moisture decline. Australian Research Council; AINSE AWARD [ALNGRA16024]; AINSE PGRA scholarship [12039] info:eu-repo/semantics/publishedVersion

Ecology and Quaternary palaeoecology have largely developed as parallel disciplines. Although both pursue related questions, information exchange is often hampered by particularities of the palaeoecological data and a communicational gap has been perceived between the disciplines. Based on selected topics and developments mainly in Quaternary palaeoecology, we show that both disciplines have converged somewhat during recent years, while we still see untapped potential for closer interactions. Macroecology is probably the discipline that most easily combines different time-scales and where co-operations between palaeoecologists, geneticists and vegetation modellers have been inspiring. Quantitative vegetation reconstructions provide robust estimates of tree composition and land cover at different spatial scales, suitable for testing hypotheses about long-term vegetation changes or as quantitative background data in studies on contemporary vegetation patterns. Palaeo-data also hold yet unexplored potential to study the drivers of long-term diversity and aspects of functional diversity may facilitate comparisons between continents and over glacial-interglacial cycles.

Using a multi-proxy analysis of a postglacial sedimentary sequence from a lowland wetland, we address the possible drivers of change in the wetland habitats and surrounding landscapes of southwestern Slovakia. A 5 m-deep core in the Parížske močiare marshes was investigated for pollen, plant macro-remains, molluscs, organic content and magnetic susceptibility. The palaeoecological record extends from the Pleistocene–Holocene transition (≥11,200 cal. BP) to the 5th millennium cal. BP and was correlated with a macrophysical climate model (MCM) and archaeological data. Our results show the transformation of an open parkland landscape with patches of coniferous forest to a temperate deciduous forest at the onset of the Holocene. The record is remarkable for an early occurrence of Quercus pollen and macro-remains around 11,200 cal. BP and its early expansion (10,390 cal. BP) in the vegetation. Such an early spread of Quercus has not previously been recorded in the region, where Corylus is usually the first to expand among temperate trees. This unusual development of forest communities was most probably triggered by a short-lived increase in precipitation and decrease in temperature, as reconstructed by the MCM model. Higher moisture availability and low temperature inhibited Corylus and favoured the spread of Quercus. Later, the climate became drier and warmer, which, together with fires, supported the expansion of Corylus. Since 7300 cal. BP, human activities became most likely the dominant influence on the landscape. Deforestation contributed to soil erosion, which halted the accumulation of organic material after 5520 cal. BP, followed by the accumulation of clay sediments.

To characterize Late Pleniglacial (LPG: 26.5e15 ka cal BP) and particularly Last Glacial Maximum (LGM: 21 � 2 ka cal BP) vegetation and climate, fossil pollen assemblages are often compared with modern pollen assemblages. Given the non-analogue climate of the LPG, a key question is how glacial pollen assemblages and thereby vegetation compare with modern vegetation. In this paper we present three LPG pollen records from the Carpathian Basin and the adjoining Carpathian Mountains to address this question and provide a concise compositional characterization of the LPG vegetation. Fossil pollen assemblages were compared with surface pollen spectra from the Altai-Sayan Mountains in southern Siberia. This area shows many similarities with the LPG vegetation of eastern-central Europe, and has long been considered as its best modern analogue. Ordination and analogue matching were used to characterize vegetation composition and find the best analogues. Our results show that few LPG pollen assemblages have statistically significant analogues in southern Siberia. When analogue pairings occur they suggest the predominance of wet and mesic grasslands and dry steppe in the studied region. Wooded vegetation types (continental and suboceanic hemiboreal forest, continental taiga) appear as significant analogues only in a few cases during the LGM and more frequently after 16 ka cal BP. These results suggest that the LPG landscape of the Carpathian Basin was dominated by dry steppe that occurred outside the river floodplains, while wet and mesic grasslands occurred in the floodplains and on other sites influenced by ground water. Woody vegetation mainly occurred in river valleys, on wet northfacing hillsides, and scattered trees were likely also present on the loess plateaus. The dominant woody species were Larix, Pinus sylvestris, Pinus mugo, Pinus cembra, Picea abies, Betula pendula/pubescens, Betula nana, Juniperus, Hippophae rhamnoides, Populus, Salix and Alnus. The pollen records suggest uninterrupted presence of mesophilous temperate trees (Quercus, Ulmus, Corylus, Fagus and Fraxinus excelsior )i n the Eastern Carpathian Mountains throughout the LPG. We demonstrate that the LPG vegetation in this area was characterized by increasing grass cover and high frequency of wildfires. We conclude that pollen spectra over represent trees in the forest-steppe landscape of the LPG, furthermore pollen-based quantitative climate reconstructions for the LPG are challenging in this area due to the scarcity of modern analogues.

Fire occurrence is driven by a complex interplay between vegetation, climatic, landform and human factors making it challenging to separate the individual effect of each variable. Here we present a reconstruction of the Holocene biomass burning history of two regions located in the Central European temperate zone that differ in the timing of the Middle Holocene expansion of broadleaf-dominated forest communities. This allowed us to investigate the effect of biotic changes on past fire activity. Multiple-site charcoal accumulation records were used to estimate regional-scale trends in biomass burning and to compare them with major trajectories of vegetation development. Extensive 14C-dated soil charcoal records collected within both regions were amalgamated using a cumulative probability function to identify a stand-scale proxy of past fire occurrence. Our results suggest that rising vegetation productivity driven by rapid Early Holocene climate amelioration enhanced biomass burning. The increased fire activity during this period was driven by both a drier- and warmer-than-present climate and easily flammable fuels produced by conifer-dominated vegetation. We identified an inhibiting effect of the concomitant Fagus sylvatica expansion on levels of biomass burning that occurred asynchronously between our mountain and mid-elevation sandstone regions 6500 cal yr BP and 4900 cal yr BP, respectively. The amount of compositional change in plant communities was more related to the transformation of major vegetation types than to fluctuations in fire activity levels. The divergent timing of the fire decline in response to the Fagus sylvatica expansion implies biotic control over biomass burning that is independent of a direct climatic influence.

In contrast to marked climate change across glacial-interglacial cycles, the Holocene epoch represents a relatively warm, stable interval. However, on finer temporal scales, it too has experienced both gradual and rapid changes in climate. In the North Atlantic region, many rapid climate changes (RCCs) coincide with ice-rafted debris (IRD) or Bond events, which are associated with cooling and suggested to occur with periodicities of 1370 ± 500 years. Given that climate is a dominant control of fire activity, regulating both vegetation productivity and fuel moisture, this study investigated the linkage between Holocene fire, IRD episodes and associated RCCs in seven high-resolution charcoal records distributed across Europe. Results show low-frequency fire periodicities of 500–600 years, 900–1400 and 2400 years that occurred simultaneously across northern and mid-latitude Europe, suggesting that regional fire disturbance responded to large-scale climate drivers. The 900–1400 year periodicity is most common among sites and of similar frequency to IRD episodes, potentially reflecting a connection between mechanisms regulating IRD flux in the North Atlantic and wildfire activity in Europe. Although the data indicate some spatial variability in fire induced by local drivers (such as vegetation and human impact) during RCC events associated with IRD peaks, broad-scale patterns are discernible. Specifically, Northern Europe burned more during the 10.2, 9.4, 8.2, 5.9 and 4.2 kiloannum before present (ka) RCC events when climate was drier, and less during the 2.9 and 1.4 ka events when climate was moister. In contrast, in mid-latitude Europe, a higher incidence of fire is documented at 8.2 and 1.4 ka when climate was drier and a lower incidence of fire is associated with moister conditions at 10.2, 9.4 and 2.9 ka. Spatial heterogeneity is evident in mid-latitude Europe during the 5.9, 4.2 and 0.4 ka events. These spatially explicit sub-continental scale differences in fire activity may be related to differences in moisture availability resulting from shifts in associated atmospheric circulation patterns.

A long-term perspective is a crucial dimension for understanding the present-day composition and structure of the Czech flora and vegetation. We outline processes that were important for the development of the present-day diversity of flora and vegetation including extinctions of taxa and ecological mechanisms operating within glacial-interglacial cycles. Further, we present the history of vegetation during the key stages in the glacial and postglacial periods. First, we outline the pattern in the vegetation during the last glacial, including a discussion of the existence of refugia for trees. We further describe the changes in vegetation during the Late Glacial, which were mostly the results of abrupt climatic events. We also present a new synthesis of the Holocene regional development in vegetation based on a Landscape Reconstruction Algorithm, which results in different regional vegetation trajectories and three main phases in the development of vegetation. Finally, we give some examples of the histories of local vegetation at several sites mainly based on plant macrofossils.

The issue of continuity in deciduous oakwood vegetation has been in the forefront of woodland ecological studies for many decades. The two basic questions that emerge from existing research are whether or not oakwoods can be characterized by long-term stability and what may be the driving forces of the observed stability or change. To answer these questions in a well-defined case study, we examined the history of a large subcontinental oakwood (Dúbrava) in the southeastern Czech Republic with interdisciplinary methods using palaeoecological and archival sources. Palaeoecology allowed us to reconstruct the vegetation composition and fire disturbances in Dúbrava in the past 2000 years, while written sources provided information about tree composition and management from the 14th century onwards. The pollen profiles show that the present oakwood was established in the mid-14th century with an abrupt change from shrubby, hazel-dominated vegetation to oak forest. This change was most probably caused by a ban on oak felling in ad 1350. From the 14th to the late 18th centuries Dúbrava had multiple uses, of which wood-pasture and hay-cutting kept the forest considerably open. The second remarkable change was dated to the late 18th century, when multiple-use management was abandoned and Dúbrava was divided into pasture-only and coppice-only parts. The last major shift occurred in the mid-19th century, when modern forestry and Scotch pine plantation became dominant. We conclude that Dúbrava Wood did not show stability in the long run and that its species composition has dramatically changed during the last two millennia. The most important driving force in the shaping and maintenance of the unique vegetation of Dúbrava was human management.

Aim Observations of long chronosequences in forest ecosystems show that, after some millennia of build-up, biomass declines in relation to the slow depletion of soil phosphorus. Plants that dominate during this period of soil impoverishment have specialized strategies for P acquisition, including ectomycorrhiza or root clusters. We use quantitative, pollen-based reconstructions of regional vegetation in four Quaternary warm stages (Holocene, Eemian, Holsteinian, Harreskovian) to test whether inferred forest cover and productivity changes are consistent with long-term modification of soil nutrient pools. Location Southern Scandinavia (Denmark, southern Sweden). Methods The REVEALS model was used to estimate regional vegetation abundances of 25 pollen-type-equivalent taxa from pollen records of large sedimentary basins in southernmost Scandinavia. Based on the estimated regional vegetation, we then calculated time-series of Ellenberg indicator values for L (light), R (soil reaction) and N (a productivity proxy). We classified the vegetation records into distinct phases and compared these phases and the samples using hierarchical clustering and ordination. Results All three interglacials developed coniferous or mixed forests. However, pure deciduous forests were never reached during the Holsteinian, while pure coniferous forests never developed in the Holocene. Above-ground productivity was inferred to be low initially, peaking in the first third of the warm stages and then slowly declining (except during the Holocene). Dominant trees of the post-peak phases all had ectomycorrhiza as a strategy for P acquisition, indicating that easily accessible P pools had become depleted. Increases in fire regimes may have amplified the inferred final drop in productivity. Mid/late Holocene productivity changes were much influenced by agricultural activities. Main conclusions REVEALS vegetation estimates combined with Ellenberg indicator values suggest a consistent pattern in warm stages of initially rising productivity, followed by a long and slow decline. The P-acquisition strategies of dominant trees indicate that the decline reflects increasing P depletion of soils.