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Despite the increasing interest in spring-fed fens’ sediments as a palaeoenvironmental archive, their potential as high-precision climatic records is rarely used to its full extent. Here, we present a detailed early to mid-Holocene record of environmental changes in the Turtul hanging spring-fed fen, northeastern Poland, to test whether the well preserved and accurately subsampled alternating peat and tufa sediments allow us to recognise short-duration local and regional climatic changes. Our reconstructions are based on a loss-on-ignition analysis of the sediment, carbon and oxygen stable isotope values of tufa, and biotic proxies: plant macrofossil and malacological analyses. A detailed environmental reconstruction was possible due to the combination of detailed sampling (1 cm intervals) and high sediment accumulation rates. The two sediment sequences collected from the fen revealed the congruent palaeoenvironmental history; however, the temporal shift associated with the distance of the coring site from the water outflow was also apparent, stressing the need for careful selection of the coring site in palaeoenvironmental research. Peat deposition at Turtul started at 10,300 cal yr BP; however, tufa precipitation did not begin before 9250 cal yr BP. During the most active tufa deposition, from 7850 to 6100 cal yr BP, a high sedimentation rate was observed (0.11–0.25 cm yr−1). We found several abrupt and short-duration declines in carbonate deposition corresponding to climatic fluctuations recorded in geological archives from the southeastern Baltic region. The carbonate drops at 8200–8130, 7900–7850, 7400–7300, 6600–6500, 5980–5870 and 5400 cal yr BP were associated with climate cooling or drying, whereas those at 10,200–9250, 8450–8340 and 6160–6100 cal yr BP can be attributed to drying with no cooling. We conclude that the evident sensitivity of the Turtul fen to climatic shifts that emerge from our high-resolution (one sample every 17 years on average) reconstruction complements the still rare high-resolution palaeoenvironmental records in the area.

Northern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal re-cords from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (similar to 9e6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Aims: Classification of European bog vegetation (Oxycocco-Sphagnetea class); identification of diagnostic species for the class and vegetation subgroups (orders and alliances); development of an expert system for automatic classification of vegetation plots; and production of distribution maps of the Oxycocco-Sphagnetea class and its alliances. Location: Europe. Methods: A data set of vegetation-plot records was compiled to include various bog types over most of the European continent. An unsupervised classification (beta-flexible linkage method, Sørensen distance measure) and detrended correspondence analysis (DCA) ordination were applied. Formal definitions of syntaxa based on species presence and covers, and respecting the results of the unsupervised classification, were developed and included in a classification expert system. Results: The Oxycocco-Sphagnetea class, its two orders (Sphagno-Ericetalia tetralicis and Sphagnetalia medii) and seven compositionally distinct alliances were formally defined. In addition to the syntaxa included in EuroVegChecklist, three new alliances were distinguished: Rubo chamaemori-Dicranion elongati (subarctic polygon and palsa mires); Erico mackaianae-Sphagnion papillosi (blanket bogs of the northwestern Iberian Peninsula); and Sphagno baltici-Trichophorion cespitosi (boreal bog lawns). The latter alliance is newly described in this article. Conclusions: This first pan-European formalized classification of European bog vegetation partially followed the system presented in EuroVegChecklist, but suggested three additional alliances. One covers palsa and polygon mires, one covers Iberian bogs with endemics and one fills the syntaxonomical gap for lawn microhabitats in boreal bogs. A classification expert system has been developed, which allows assignment of vegetation plots to the types described.

Rising temperatures may endanger fragile ecosystems because their character and key species show different habitat affinities under different climates. This assumption has only been tested in limited geographical scales. In fens, one of the most endangered ecosystems in Europe, broader pH niches have been reported from cold areas and are expected for colder past periods. We used the largest European-scale vegetation database from fens to test the hypothesis that pH interacts with macroclimate temperature in forming realized niches of fen moss and vascular plant species. We calibrated the data set (29,885 plots after heterogeneity-constrained resampling) with temperature, using two macroclimate variables, and with the adjusted pH, a variable combining pH and calcium richness. We modelled temperature, pH and water level niches for one hundred species best characterizing European fens using generalized additive models and tested the interaction between pH and temperature. Fifty-five fen species showed a statistically significant interaction between pH and temperature (adj p ˂ .01). Forty-six of them (84%) showed a positive interaction manifested by a shift or restriction of their niche to higher pH in warmer locations. Nine vascular plants and no moss showed the opposite interaction. Mosses showed significantly greater interaction. We conclude that climate significantly modulates edaphic niches of fen plants, especially bryophytes. This result explains previously reported regional changes in realized pH niches, a current habitat-dependent decline of endangered taxa, and distribution changes in the past. A warmer climate makes growing seasons longer and warmer, increases productivity, and may lower the water level. These effects prolong the duration and intensity of interspecific competition, support highly competitive Sphagnum mosses, and, as such, force niches of specialized fen species towards narrower high-pH ranges. Recent anthropogenic landscape changes pose a severe threat to many fen species and call for mitigation measures to lower competition pressure in their refugia.

Aims: To create a comprehensive, consistent and unequivocal phytosociological classification of European marsh vegetation of the class Phragmito-Magnocaricetea. Location: Europe. Methods: We applied the Cocktail method to a European data set of 249, 800 vegetation plots. We identified the main purposes and attributes on which to base the classification, defined assignment rules for vegetation plots, and prepared formal definitions for all the associations, alliances and orders of the class Phragmito-Magnocaricetea using formal logic. Each formula consists of the combination of “functional species groups”, cover values of individual species, and in the case of high-rank syntaxa also of “discriminating species groups” created using the Group Improvement (GRIMP) method. Results: The European Phragmito-Magnocaricetea vegetation was classified into 92 associations grouped in 11 alliances and six orders. New syntaxa (previously invalidly published according to the International Code of Phytosociological Nomenclature) were introduced: Bolboschoeno maritimi-Schoenoplection tabernaemontani, Glycerio maximae-Sietum latifolii, Glycerio notatae-Veronicetum beccabungae, Schoenoplectetum corymbosi and Thelypterido palustris-Caricetum elongatae. Based on a critical revision, some other syntaxa were rejected or excluded from the class Phragmito-Magnocaricetea. Conclusions: This work provides the first consistent classification of the class Phragmito-Magnocaricetea at the European scale, which is an important tool for nature conservation. Our classification largely respects previously existing concepts of syntaxa, but it also proposes modifications to the recently published EuroVegChecklist. This work also provides a protocol that can be used for extending the current classification to new syntaxa and geographical regions.

Here, for the first time in SE Poland, we document the long-term development of a rich fen and assess its sensitivity to climate change and human impacts over the last ca. 3500 years. Our results are based on a high-resolution, continuous plant macrofossil remains, mollusc and pollen record, complemented by geochemical, mineral magnetic and physical characterisation, and radiocarbon dating from Bagno Serebryskie rich fen located in SE Poland. Based on the palaeoecological data we distinguished five stages of wet habitat conditions: 5000–3300, 2800–2150, 1600–1100, 750–230, 150–10 cal yr BP and five dry periods at ca. 3300–2800, 2150–1600, 1100–750, 230–150, 10 to − 64 cal yr BP. The pollen and geochemistry records, particularly Pb, show that the first human activity in the study area occurred ca. 3200 cal yr BP and increased markedly from 500 cal yr BP affecting local plant development including the population size of Cladium mariscus. Our study has shown that despite human impact (drainage, fire), Bagno Serebryskie peatland has hosted rare, presently protected species, such as Cladium mariscus for hundreds of years. We conclude that, in common with ombrotrophic bogs, rich fen ecosystems can provide a reliable source of palaeoclimatic and palaeohydrological data. Our study also shows that a large peatland (376 ha) can be as sensitive a palaeohydrological archive as smaller mires.

We present the paleoecological development of a rich fen located in the dune area on the SE Baltic coast, during the last 7500 years. The Apsuciems Mire hosts rare and endangered plant communities in Europe, such as Schoenus ferrugineus and Cladium mariscus. Analysis at high-resolution of plant macroremains in two peat cores was carried out to reconstruct local vegetation succession and fluctuations in moisture availability on the peatland, while a pollen record was developed to reconstruct plant succession, moisture variability and human activity at the regional scale. Based on the presence or the absence of macroremains of plants that occur in wet habitat e.g. Cladium mariscus, Schoenoplectus tabernaemontani, Alisma plantago-aquatica and Botrycoccocus we distinguished four wet periods ca. 6000, 2000, 1750–1550, 1200–150 cal yr. BP and four dry periods (ca. 7000, 4600–4200, 1800–1750, 1550–1200 cal yr. BP) in the peatland’s development. A water level increase at 1200 cal yr. BP triggered the development of plant communities containing Chara sp., Schoenoplectus tabernaemontani, then Cladium mariscus. Our study shows a link between climate change at the regional scale and vegetation development in Apsuciems Mire. We showed that changes in vegetation structure during last 150 years was caused by drainage and human activity.

International audience; Questions: What is the distribution of base-rich fen vegetation and the specia- list species along European biogeographic regions? How do the gradients in spe- cies composition correlate to geography and climate at continental scale? What are the implications of such patterns for the classification of these habitats?Location: Fifteen countries of Central, Western and Northern Europe.Methods: We compiled a vegetation plot database of base-rich fens and related communities including vascular plants and bryophytes. The initial data set with 6943 plots was filtered according to the presence of specialists using discriminant analysis. We used DCA to analyse the correlation of species composition with geography and climate, and kriging interpolation for mapping gradients in the study area. Modified TWINSPAN was used to detect major vegetation groups. The results of the whole data set (plot size 1–100 m2) were compared with those obtained from two subsets with plots of 1–5 m2 and 6–30 m2.Results: Most of the specialists were distributed among all the biogeographic regions, but many were more represented in the Alpine than in the Atlantic, Boreal and Continental regions. Variation in species composition was mainly correlated to temperature, precipitation and latitude in the three data sets, showing a major gradient from (1) alpine belt fens characterized by spring species to (2) small sedge fens mainly distributed in mountain regions and (3) boreo-temperate fens reflecting waterlogged conditions.Conclusions: Base-rich fen communities are widely distributed across Europe- an biogeographic regions, but the Alpine region can be considered as the compositional centre of this vegetation type. Large-scale gradients of species composition are mainly explained by climate, while the influence of latitude is probably correlated to increasing water table in the boreo-temperate regions. These gradients can be better understood by differentiating three major vegeta- tion types, which should be considered when establishing classification systems of base-rich fens in Europe.

The TURBOVEG database Mire Vegetation Database of Latvia (GIVD ID EU-LV-002) comprises 1927 releves described in mires of Latvia by the author since 1995 and is annually updated. The plot size is 1 4 m. Percentage cover of Vascular plants and bryophytes were evaluated for each sample plot. It also includes 156 releves on vegetation changes in pine forests after selective cutting and heath mowing in Erica tetralix habitats. This is a private database. The data are mainly used for preparation of mire vegetation classification system of Latvia. So far the database covers two classes Phragmito-Magnocaricetea and ScheuchzerioCaricetea nigrae. When Vegetation Database of Latvia at Laboratory of Geobotany of Institute of Biology will be created it will be part of national vegetation database.

WetVegEurope is a research project (http://www.sci.muni.cz/botany/vegsci/wetveg) whose goal is to provide a synthesized formalized classification of the aquatic and marsh vegetation across Europe at the level of phytosociological associations. In order to achieve the project objective, a WetVegEurope database has been created (GIVD ID: EU-00-020, http://www.givd.info/ID/EU-00-020), which currently contains 375,212 vegetation plots of aquatic, marsh and wet vegetation types from 33 European countries. The WetVegEurope database includes datasets from pre-existing national and thematic databases and also 10,616 plots previously not digitalized or even unpublished. This database offers an extensive source of data for future studies on aquatic and marsh plant species and vegetation types at the European scale.