Fen Vegetation Research Articles

Self‐facilitation and negative species interactions could drive microscale vegetation mosaic in a floating fen

AbstractAimThe formation of a local vegetation mosaic may be attributed to local variation in abiotic environmental conditions. Recent research, however, indicates that self‐facilitating organisms and negative species interactions may be a driving factor. In this study, we explore whether heterogeneous geohydrological conditions or vegetation feedbacks and interactions could be responsible for a vegetation mosaic of rich and poor fen species.LocationLake Aturtaun, Roundstone Bog, Ireland.MethodsIn a floating fen, transects were set out to analyze the relation between vegetation type and rock–peat distance and porewater electrical conductivity. Furthermore, three distinct vegetation types were studied: rich fen, poor fen and patches of poor fen within rich fen vegetation. Biogeochemical measurements were conducted in a vertical profile to distinguish abiotic conditions of distinct vegetation types.ResultsGeohydrological conditions may drive the distribution of poor and rich fen species at a larger scale in the floating fen, due to the supply of minerotrophic groundwater. Interestingly, both rich and poor fen vegetation occurred in a mosaic, when electrical conductivity values at 50 cm depth were between 300 µS/cm and 450 µS/cm. Although environmental conditions were homogeneous at 50 cm, they differed markedly between rich and poor fen vegetation at 10 cm depth. Specifically, our measurements indicate that poor fen vegetation lowered porewater alkalinity, bicarbonate concentrations and pH. No effects of rich fen vegetation at 10 cm depth on biogeochemistry was measured. However, rich fen litter had a higher mineralization rate than poor fen litter, which increases the influence of minerotrophic water in rich fen habitat.ConclusionsThese results strengthen our hypothesis that species can drive formation of vegetation mosaics under environmentally homogeneous conditions in a floating fen. Positive intraspecific self‐facilitating mechanisms and negative species interactions could be responsible for a stable coexistence of species, even leading to local ecosystem engineering by the species, explaining the local vegetation mosaic at the microscale level in a floating fen.

Estimation of greenhouse gas emission reductions based on vegetation changes after rewetting in Drentsche Aa brook valley

Rewetting can effectively reduce greenhouse gas (GHG) emissions from drained peatlands. Reliable emissions estimation approaches are needed for accounting of such reductions and for evaluating the potential in terms of carbon credits. Annual mean water level and vegetation are reliable and widely used proxies for emissions estimation. However, indications of water level based on plant species (e.g. Ellenberg Indicator Values) are qualitative with large variances, and there are insufficient high-quality flux measurement data to support the direct use of vegetation as a proxy for GHG fluxes. Here we combine vegetation and water level proxies to estimate emissions, by using bioindication of vegetation communities for water level together with the linear correlation between annual mean water level and GHG fluxes. This approach is demonstrated in the Drentsche Aa brook valley in The Netherlands, where peatlands were rewetted to restore rich fen vegetation. Biodiversity of the landscape was monitored by repeated vegetation mapping before and after rewetting, which enables the estimation of emissions reduction as a co-benefit. Mean annual water level values are assigned to mapped vegetation types using existing data on water level dynamics from measurements on corresponding plant communities. GHG emissions are estimated using linear regression models of gas fluxes against mean annual water levels. This approach provides spatially explicit and quantitative estimation of mean annual water levels and GHG fluxes. When combined with information on spatial patterns and variances, the resulting estimations can promote recognition of the carbon co-benefits of biodiversity restoration while facilitating more site-specific optimisation of management practices.

Plant responses to nutrient addition and predictive ability of vegetation N:P ratio in an austral fen

Abstract Previous studies of the N:P ratio in wetland plants have been carried out in northern hemisphere wetlands where atmospheric nitrogen deposition is higher. There is little research on foliar N:P ratio as a potential indicator of nutrient limitation in vegetation communities in southern hemisphere wetlands. This study aimed to redress this knowledge gap and answer the following questions: how well does the plant tissue nitrogen to phosphorus (N:P) ratio predict wetland plant community nutrient limitation, as indicated by vegetation standing stocks and below‐ground biomass, in southern hemisphere fens? Secondly, what are the impacts of realistic upper levels of farm nutrient run‐off on natural montane fen vegetation? Low (35 kg ha−1 year−1) and high (70 kg ha−1 year−1) levels of nitrate‐N or ammonium‐N with and without P (20 kg ha−1 year−1) were added to 81 vegetation plots over a period of 2.75 years. Species composition, plant nutrient status, and above‐ground live vegetation standing stocks were assessed after 3 years, and below‐ground biomass after 2 years. Plant tissue analysis suggested the community was N limited or N and P co‐limited; we found greater standing stocks of vegetation in plots treated with 70 kg ha−1 year−1 ammonium‐N, indicating N limitation. No difference between other treatments was found in above‐ground standing stocks or below‐ground biomass. Plant species cover increased in both high N treatments, consistent with N limitation. These changes in plant species cover were accompanied by significant decreases in species richness in both high N treatments. Native species dominated the vegetation and this was unaffected by nutrient addition (90% cover). This is one of the first studies to test and find support for the N:P ratio in southern hemisphere wetlands. Observed declines in species richness after N fertilisation in an N‐limited fen suggests increased N may pose risks to austral wetlands. Responses by plant communities (changes in composition, biomass) to lower levels of nutrient addition may require longer periods of fertilisation to be apparent in slow growing ecosystems.

Macroclimate and local hydrological regime as drivers of fen vegetation patterns in Tierra del Fuego (Argentina)

AbstractIn southern South America, a sharp macroclimatic gradient is found, triggered by the Pacific oceanic influence through the Andes. Mires are substantial landscape units along the gradient, where they play varying roles through the area and include varying plant communities. In this study, we analysed the relationship between vegetation and main abiotic factors in the minerotrophic mires (fens) at two different scales.We chose three fens in Isla Grande from Cordillera and Magellanic Steppe zones and their ecotone. There we characterized the distinct habitats by means of monitoring the water table fluctuations, the peat and the groundwater chemistry, and the vascular plant species composition.The main floristic patterns were revealed by means of classification and ordination of 75 vegetation plots. Thus, we classified the relevés through multivariate analyses into six plant community types, two of which found in each fen. Behind the floristic distinctiveness of each site and each community type, structural vegetation descriptors such as species richness were similar. Overall, water table variables and groundwater chemistry showed the most important environmental differences between fens.Our data point that the main environmental force driving vegetation patterns was the macroclimatic gradient, which shapes the regional floristic pools. This gradient would be also responsible for modifying the local conditions of the fen habitats, mostly in the form of broadening the hydrological conditions within the fens of the Steppe. At each fen, the hydrological regime is the main factor in the distribution of vascular plants, particularly through the varying water table depths.

Comparing ultra‐high spatial resolution remote‐sensing methods in mapping peatland vegetation

AbstractQuestionsHow to map floristic variation in a patterned fen in an ecologically meaningfully way? Can plant communities be delineated with species data generalized into plant functional types? What are the benefits and drawbacks of the two selected remote‐sensing approaches in mapping vegetation patterns, namely: (a) regression models of floristically defined fuzzy plant community clusters and (b) classification of predefined habitat types that combine vegetation and land cover information?LocationTreeless 0.4 km2 mesotrophic string–flark fen in Kaamanen, northern Finland.MethodsWe delineated plant community clusters with fuzzy c‐means clustering based on two different inventories of plant species and functional type distribution. We used multiple optical remote‐sensing data sets, digital elevation models and vegetation height models derived from drone, aerial and satellite platforms from ultra‐high to very high spatial resolution (0.05–3 m) in an object‐based approach. We mapped spatial patterns for fuzzy and crisp plant community clusters using boosted regression trees, and fuzzy and crisp habitat types using supervised random forest classification.ResultsClusters delineated with species‐specific data or plant functional type data produced comparable results. However, species‐specific data for graminoids and mosses improved the accuracy of clustering in the case of flarks and string margins. Mapping accuracy was higher for habitat types (overall accuracy 0.72) than for fuzzy plant community clusters (R2 values between 0.27 and 0.67).ConclusionsFor ecologically meaningful mapping of a patterned fen vegetation, plant functional types provide enough information. However, if the aim is to capture floristic variation in vegetation as realistically as possible, species‐specific data should be used. Maps of plant community clusters and habitat types complement each other. While fuzzy plant communities appear to be floristically most accurate, crisp habitat types are easiest to interpret and apply to different landscape and biogeochemical cycle analyses and modeling.

THE EVALUATION OF STABLE ISOTOPIC RATIOS 13C AND 15N IN HUMIC ACIDS ALONG A FEN PEAT PROFILE

Mires are known as consistent environmental archives, but humic acids are the fraction of peat that is most recalcitrant and refractory to organic matter degradation, thus data on environmental changes during mire development can be recorded into them. This work was focused on the studies of stable isotopic ratios delta carbon-13 and delta nitrogen-15, and their distribution in humic acids within fen peat layers of different depths and peat composition. The variations in delta carbon-13 reflect isotopic variations in peat-forming plants over time and can be considered as a function of photosynthetic pathway that is being used to fix carbon dioxide. At the same time, variations in delta nitrogen-15 show nitrogen fixation in peat-forming plants and can be traced along with peat decomposition degree and depth. Properties of humic acids were studied in 2018 at 3 fens located in Latvia and Southern Finland, and comparatively they show properties. The method used for the determination of stable isotopes was the isotope-ratio mass spectrometry that was performed in the Faculty of Chemistry, University of Latvia. Results on delta carbon-13 indicate signal of C3 peat-forming plants, while signal of C4 peat-forming plants is not evident, which can be explained by non-efficient carbon dioxide fixation in fen vegetation. Results on delta nitrogen-15 show variations in nitrogen fixation in fen vegetation. Data show nitrogen fixation in terrestrial plants, however significant shifts in absolute isotope values indicate dependence on variations in peat decomposition degree and botanical composition. Data suggest that differences in peat botanical composition, decomposition degree and site dependent characteristics reflect in differences in delta carbon-13 and delta nitrogen-15 variations

Plant functional traits reveal strong effects of anoxia and nutrient limitation on species pool filtering in a riverine rich fen system

ABSTRACTBackground: In fens, plant species composition is predominantly controlled by two environmental factors: root anoxia and low nutrient availability.Aims: We asked how these filters were reflected to the functional structure of plant communities in natural and drained rich fens.Methods: We analysed traits related to species response to anoxia and nutrient availability, using single-trait and multi-trait approaches in fens of a river valley (Biebrza, Poland). We evaluated results concerning multi-trait indices using a null model consisting of simulated communities.Results: Mycorrhizal status and specific leaf area (SLA) clearly distinguished the communities with different levels of anoxia and nutrient deficiency. Mean values, ranges and variance of canopy height showed the differences in the distribution of plant heights among analysed communities.Conclusions: Functional traits distinguish plant communities of the most endangered mesotrophic fens from eutrophic and drained fens. We highlight the role of nutrient and oxygen deficiency in the assembly of fen vegetation and show the impact of the altered environment on the composition of communities in degraded habitats. We demonstrate that single-trait indices are suitable for identifying of environmental filtering in different types of fen communities. We suggest that caution is justified when using multi-trait indices to assess vegetation patterns.

To mow or not to mow? Plant functional traits help to understand management impact on rich fen vegetation

AbstractQuestionsFens are important conservation targets in temperate Europe. When hydrologically undisturbed, fens remain open for millennia. However, unaltered fens are scarce, and today their biodiversity largely depends on conservational mowing applied to prevent successional shifts. However, the effects on community structure and conservation values are uncertain, and management might not always be needed where it is a priori applied by managers. Thus, within the presented study, we ask the following questions: (a) How is the species and functional composition of fens influenced by mowing? (b) Does mowing increase the conservation value of fen ecosystems?LocationLowland fens, northern Poland.MethodsThe sample consisted of 27 pairs of mown and unmown plots, located within ten sites. Ordination methods were used to assess the influence of mowing on species composition. Functional traits related to competitiveness, flowering time, mycorrhizal associations and functional groups were used to characterize plant communities and species richness, and the number of specialist and red‐listed species was used to evaluate conservation values. Differences between mown and unmown plots were assessed using linear mixed‐effect models and the effect size approach.ResultsManagement of fens suppresses the growth of trees, shrubs and highly competitive herbaceous species and inhibits the encroachment of Sphagnum mosses. At the same time, it enhances the establishment of species from other ecosystems (grasses, ruderal species, species of drier sites) within fens and alters the microtopography of the fen surface.ConclusionsMowing can enhance species richness and the presence of rich fen specialists in transformed sites, but it can lead to fen ecosystem deterioration towards managed meadow communities within sites sustaining many typical fen species and functional characteristics.

From Mountains to Plains: Ecological Structure of the South Ural (Russia) Fen Vegetation

This study focuses on comparing the driving ecological factors and community diversity of fen vegetation from the plain part of the South Ural region with those of the mountain fen vegetation, previously described by us (Ivchenko and Znamenskiy Russian Journal of Ecology 47:453–459, 2016), by means of vegetation data clustering and gradient analysis. The indicator values by several authors (H Ellenberg, E Landolt, LG Ramensky, DN Tsyganov) and WorldClim bioclimatic variables were used to determine the ecological meaning of the gradients. We found that the main gradient for both plain and mountain fen vegetation is the “poor-rich fen” gradient, which depends on local substrate chemical composition. The second gradient is associated with moisture, which tends to increase consistently both from mountains towards plains and across plains from peneplain towards West Siberian Lowland. The moisture gradient proved to be unrelated to precipitation, which increase linearly from plains towards mountains. The community diversity in the mountain part is higher than in the plain part. The fen vegetation of plains and mountains overlap in ordination space but a half of the types described for mountain fen vegetation do not occur on plains, while two types of plain fen vegetation from the West Siberian Lowland are absent on mountains.

Relict occurrences of boreal brown-moss quaking rich fens in the Carpathians and adjacent territories

Quaking rich fens dominated by boreal semi-aquatic brown-mosses such as Scorpidium scorpioides and Calliergon trifarium are extremely rare in the Carpathians. These fens harbour endangered species persisting at few localities in the region. However, their phytosociological classification has not been sufficiently solved yet, because they lack Sphagnum species as well as calcicole species characteristic for the Caricion davallianae alliance. A recent pan-European synthesis on fen vegetation suggests that these fens belong to the Stygio-Caricion limosae alliance (boreal rich fen vegetation). The isolated occurrence of this alliance southward of the boreal zone and outside the Alps is rather exceptional and might represent a relict from an early post-glacial period. In this study, we compared phytosociological data for the Stygio-Caricion limosae alliance between Northern Europe and the Carpathians plus adjacent regions (the Bohemian Massif, the Dinaric Alps) using NMDS and cluster analysis. We found that the species composition of brown-moss quaking rich fens in Central and Southeastern Europe corresponds well with that in Northern Europe, confirming their assignment to Stygio-Caricion limosae. We further reconstructed the potential past distribution of the alliance in Czech Republic and Slovakia using available floristic and macrofossil data. Macrofossil data suggest that this vegetation type had been much more common in Central Europe and that today it persists only in ancient fens, showing the long-term stability of environmental conditions. The main causes of its present-day rarity are Middle-Holocene woodland phases in fens and recent water table decreases caused by anthropogenic deterioration of the water regime in the landscape.

Environmental drivers of subalpine and alpine fen vegetation in the Southern Rocky Mountains, Colorado, USA

Fens are widely distributed wetlands worldwide and provide vital habitat for plant and animal species in mountainous regions. Alpine fens are rare in the Rocky Mountains and concentrated in the San Juan Mountains where broad regions at high elevation have relatively level topography and suitable climate to favor peat accumulation. Studies of montane and boreal peatlands have identified water chemistry as a main driver of vegetation composition. This study investigated whether similar drivers of vegetation composition are important for alpine and subalpine fens in the San Juan Mountains of Colorado, USA. Water chemistry variables were most important in structuring subalpine and alpine fen vegetation. However, these variables explained considerably less variation in alpine than subalpine fen vegetation. In addition, lower variance of water chemistry in alpine fens did not lead to lower beta diversity of vegetation in alpine than in subalpine fens. Although alpine and subalpine fen vegetation supports similar beta diversity, key differences occur in the environmental drivers of their vegetation composition.

Long-term fire effects of the drained open fen on organic soils

AbstractFire has considerable impact on vegetation and organic soils properties. As we observed that the differences between vegetation of burnt and unburnt areas on the rich fen are visible 11 years after the fire, we assumed that the post-fire changes are long lasting, yet limited exclusively to the burnt areas. In order to check this hypothesis we studied spatial differentiation of physical and chemical properties of soils, and productivity capacities of burnt and unburnt areas in the fen in Biebrza National Park. We took soil samples from the neighboring burnt and unburnt areas, from the depth of 0–30 cm and 30–50 cm. We analyzed 21 parameters of the soils including: pH, ash content, moisture, bulk density, exchangeable K, Na, Ca, available P, N-NH4+, N-NO3−, total N, C, K, Na, Ca, Mg, Fe, P; and calculated C:N, C:P ratios. Surface layer of the burnt soils differed significantly from the unburnt soils in respect of 17 out of 21 parameters. The most pronounced difference was observed for available phosphorous (on average 6 times higher for the burnt soils). The differences in the deeper layer were mostly insignificant. The burnt areas were also characterized by twofold higher plant productivity than recorded for the unburnt areas. The influence of fire on peaty soils was long lasting but mostly limited to the surface layer of the soils. In the case of particular soil features, the post-fire differences were modified by advanced muck formation (moorshing) processes in the unburnt areas. Since the fire led to long lasting increase of fertility, the recovery of fen vegetation is unlikely.

Convergence and impoverishment of fen communities in a eutrophicated agricultural landscape of the Czech Republic

AbstractQuestionsOn‐going rapid loss of fen biodiversity in Central Europe is well known, but rigorous testing of this is complicated. We compared historical and present‐day vegetation plot records from a cultural landscape rich in fishponds, where recent eutrophication and water table manipulations threaten the unique fen diversity. We assess species composition change over the last 50 yr.LocationTřeboň Basin, Czech Republic.MethodsFirst, we revisited historical vegetation plots to collect present‐day data and then identified the most similar present‐day record (the present‐day counterpart) because no permanent plots were available. Second, we inferred water level, pH and conductivity (a proxy of mineral richness) using a training set of present‐day field measurements, and calculated Ellenberg indicator values. Then we applied modified TWINSPAN classification, CCA, PERMANOVA, PERMDISP and RMANOVA in order to test changes in the species composition, β‐diversity and environmental conditions between the historical records and their present‐day counterparts.ResultsFen vegetation has persisted on half of the sites. Out of four vegetation types, poor fens and especially flooded fens were over‐represented in the present‐day subset, while rich fens and quaking fens were under‐represented. Overall species composition differed between historical plots and their present‐day counterparts, even within individual vegetation types. Historical rich fens showed significantly higher β‐diversity than their present‐day counterparts, which predominantly represent flooded fens. Inferred water level and its fluctuation, Ellenberg moisture and nutrient values have increased, while inferred pH, conductivity and Ellenberg light value have decreased.ConclusionsThe historically wide array of fen vegetation has turned into a homogeneous and floristically depauperate set of acidic yet productive flooded fens with a high water level. Rich and quaking fens that were both low in nutrient availability and had a stable water level near the moss layer experienced a large and substantial reduction and have become rare in the landscape. Eutrophication combined with a lack of management has resulted in fen species persisting only in flooded fens. However, fluctuating water levels and high nutrient availability in flooded fens favour productive Sphagnum fens over the other vegetation types, and, importantly, do not support some endangered fen species.

Controls on plot-scale evapotranspiration from a constructed fen in the Athabasca Oil Sands Region, Alberta

In the Athabasca Oil Sands Region of the Western Boreal Plain mining companies now recognize the importance of reclaiming peatlands, as they cover >50% of the pre-mined regional landscape. To date, reclamation efforts have focused on marsh and open water wetlands. However, these wetland systems are not abundant in the sub-humid climate of the WBP because of their excessive evapotranspiration (ET) losses, compared to peatland wetlands. The experimental Nikanotee Fen was constructed as part of the landscape reclamation, engineered with the intent to support natural fen vegetation and hydrologic processes. The influences of vegetation and treatment types on plot-scale energy fluxes and ET demands were examined over the 2014 growing season, one year post-construction. Actual ET and environmental variables, such as water table, soil moisture, temperature and relative humidity, were monitored in thirty-one study plots comprising control, moss and seedling plots (with and without wood-strand mulch), as well as three ponds. Actual ET was measured with weighing lysimeters and used to correct equilibrium ET, calculated using the Priestley-Taylor combination method. A roaming meteorological station was instrumented to quantify and compare available energy over different cover types. Modeled plot-scale ET was validated against continuously measured eddy covariance ET values. Cumulative ET exceeded precipitation in all plot types with average rates of 4.4, 3.2, 3.9 and 2.8mm/day from open water, control, seedling and moss plots, respectively. Mulch reduced ET rates in both seedling and moss plots, where moss-mulch plots showed the lowest rates (2.4mm/day). The presence of mulch lowered the near-surface vapour pressure deficit, thus providing a more favorable microclimate for moss establishment by elevating near-surface relative humidity and reducing air and soil temperature by ∼2°C. Although vapour pressure deficit did not significantly control ET (p>0.05), mulch appeared to have a greater influence on ET in moss plots than seedling plots. Water table position displayed a weak yet significant (p<0.05) control on ET in seedling plots. As these reclamation practices have not yet been well tested in the Alberta oil sands region; this study provides recommendations to reduce evaporative stress and aid in the establishment of functioning constructed peatland ecosystems.

Disentangling the pollen signal from fen systems: Modern and Holocene studies from southern and eastern England

Thick deposits of peat derived from fen environments accumulated in the coastal lowland areas adjacent to the North Sea during the middle and late Holocene. These sediments are frequently used in pollen-based reconstructions of in situ and more distant vegetation. However, discriminating between wetland and dry land originating pollen signals, and between the potential fen communities present in the wetland, is complex. In this study, a suite of analytical approaches are used to explore the pollen signal of modern fen communities and compare them against Holocene pollen assemblages. At two sites in eastern England, Woodwalton Fen and Upton Broad, vegetation composition was recorded around a series of moss polster sampling points. The communities investigated included herbaceous fen communities under different cutting regimes, a grazed area, glades, and woodland with canopies dominated by Alnus glutinosa and Betula. Cluster analysis is used to provide an overview of, and compare the structure within, the datasets consisting of the vegetation, the vegetation converted to palynological equivalents, and the pollen data. It is demonstrated that any loss of taxonomic precision in pollen identifications does not pose particular problems when attempting to identify fen communities, including tall-herbaceous vegetation, in the pollen record. Indices of Association imply pollen presence can be interpreted as indicating the local presence for some taxa, though few of these are confined to a particular community. Herbaceous fen vegetation subject to different management regimes are, however, shown to produce distinctive pollen signatures. Middle and late Holocene pollen assemblages from eastern (Fenland) and southern (Romney Marsh) England, interpreted as derived from fen vegetation, are compared against the modern pollen dataset using ordination. Most of the fossil samples plot out within or adjacent to the groupings produced by the modern samples in the ordinations. While these investigations demonstrate that modern pollen work can help improve the interpretation of Holocene assemblages they also call attention to a number of limitations including the restricted range of communities from which modern samples are currently available and the potential for non-analogous modern vegetation. The paper concludes with ideas to aid the interpretation of pollen data collected from fen peats and suggestions for future work.

Flowering in the Rich Fen Species Eriophorum latifolium Depends on Climate and Reproduction in the Previous Year

In this long-term study, we identify the climate variables most important to flowering density in Eriophorum latifolium in boreal rich fen vegetation, and assess their relative importance. We analysed time-series data (1982–2008) of flowering density in 126 permanent plots in an oceanic and a continental area in Norway, and developed an autoregressive model where the density of flowering plants was determined by the cost of previous flowering, climate during the same year as flowering, and climate during the year prior to flowering. The cost of reproduction was the most influential of the factors affecting flowering. Our results suggest that dry conditions during the previous summer affected flowering negatively in the oceanic population, but had no effect in the continental population. We attribute this to differences in hydrology, with steeply sloping fens in the oceanic area, and gently sloping, spring-fed fens in the continental area. Furthermore, flowering increased with the length of the previous growing season (oceanic population), decreased with the amount of precipitation during the previous spring (continental population), and increased with temperature in spring the same year (both populations). We conclude that climate conditions during the previous year are more important than climate conditions during the year of flowering.

Formalized classification of European fen vegetation at the alliance level

AbstractAimsPhytosociological classification of fen vegetation (Scheuchzerio palustris‐Caricetea fuscae class) differs among European countries. Here we propose a unified vegetation classification of European fens at the alliance level, provide unequivocal assignment rules for individual vegetation plots, identify diagnostic species of fen alliances, and map their distribution.LocationEurope, western Siberia and SE Greenland.Methods29 049 vegetation‐plot records of fens were selected from databases using a list of specialist fen species. Formal definitions of alliances were created using the presence, absence and abundance of Cocktail‐based species groups and indicator species. DCA visualized the similarities among the alliances in an ordination space. The ISOPAM classification algorithm was applied to regional subsets with homogeneous plot size to check whether the classification based on formal definitions matches the results of unsupervised classifications.ResultsThe following alliances were defined: Caricion viridulo‐trinervis (sub‐halophytic Atlantic dune‐slack fens), Caricion davallianae (temperate calcareous fens), Caricion atrofusco‐saxatilis (arcto‐alpine calcareous fens), Stygio‐Caricion limosae (boreal topogenic brown‐moss fens), Sphagno warnstorfii‐Tomentypnion nitentis (Sphagnum‐brown‐moss rich fens), Saxifrago‐Tomentypnion (continental to boreo‐continental nitrogen‐limited brown‐moss rich fens), Narthecion scardici (alpine fens with Balkan endemics), Caricion stantis (arctic brown‐moss rich fens), Anagallido tenellae‐Juncion bulbosi (Ibero‐Atlantic moderately rich fens), Drepanocladion exannulati (arcto‐boreal‐alpine non‐calcareous fens), Caricion fuscae (temperate moderately rich fens), Sphagno‐Caricion canescentis (poor fens) and Scheuchzerion palustris (dystrophic hollows). The main variation in the species composition of European fens reflected site chemistry (pH, mineral richness) and sorted the plots from calcareous and extremely rich fens, through rich and moderately rich fens, to poor fens and dystrophic hollows. ISOPAM classified regional subsets according to this gradient, supporting the ecological meaningfulness of this classification concept on both the regional and continental scale. Geographic/macroclimatic variation was reflected in the second most important gradient.ConclusionsThe pan‐European classification of fen vegetation was proposed and supported by the data for the first time. Formal definitions developed here allow consistent and unequivocal assignment of individual vegetation plots to fen alliances at the continental scale.

Reintroduction of fen plant communities on a degraded minerotrophic peatland

We have developed an approach to restore bogs after peat extraction, but, when sedge-peat layers are exposed, the minerotrophic remnant peat conditions require restoration towards a fen ecosystem. Three restoration techniques, all including rewetting actions, were tested to assist fen vegetation recovery. None of the restoration techniques were effective at establishing fen bryophytes. However, for vascular plants, two techniques gave promising results in terms of species composition, although the vascular plant cover remained lower than in the reference fens. Depending on the site conditions, we suggest applying two restoration techniques to restore peatlands in areas of exposed sedge peat. In areas where sparse cover of fen species may have spontaneously established, rewetting should be carried out to raise water levels and create favourable conditions for their expansion. In areas covered with undesirable species or with inadequate topography for rewetting, surface peat should be remodeled and vegetation introduced. Since mechanized diaspore transfer did not result in a satisfactory cover of fen plants, other means of introduction could be considered, alone or in combination. A complementary fertilization experiment showed that fertilization with phosphorus could be an effective solution to enhance the establishment of mechanically introduced plant diaspores.

Meesia triquetra, a New Relict Moss for the Republic of Macedonia

Peterka, T., Plesková, T., Palpurina, S., Kalníková, V., Lazarević, P. M. & Hájek, M. 2016. Meesia triquetra, a new relict moss for the Republic of Macedonia. — Herzogia 29: 66–71.Meesia triquetra is a circumpolar boreo-arctic moss species typical for well preserved fens, and is rare in southern Europe. During field research on mire vegetation in the Balkan Peninsula, a population of Meesia triquetra was found at the Begovo pole wetland in the Jakupica Mountains. It is the first record of this species for the Republic of Macedonia. A description of the locality, ecological conditions and vegetation is presented. The moss grows here in the sedge-moss vegetation similar to temperate fens of the alliance Caricion davallianae. The vegetation with Meesia triquetra in Begovo pole was evaluated in the context of fen vegetation more generally in the Balkans using detrended correspondence analysis. The study site appeared to be similar to other Balkan calcium-rich brown-moss fens without calcium carbonate precipitation. This habitat resembles the optimum habitat of the species in central and northern Europe.

Mid- and late-Holocene vegetation history, climate and human impact in the forest-steppe ecotone of European Russia: new data and a regional synthesis

Appropriate management of contemporary environments requires knowledge of their long-term history. We use palaeoecological data to explore how contemporary forest-steppe environments have been shaped by climate change and human impacts through the Holocene using the western Mid-Russian Upland as a case-study. Our paper presents new reconstructions of Mid- and Late Holocene climate, vegetation dynamics and local environmental change based on pollen, plant macrofossil and testate amoeba records from a site at Selikhovo (Mid-Russian Upland, Russia). Eutrophic fen vegetation dominated by Phragmites australis developed around 6800 cal year BP and has been resilient to episodes of local burning and variable input of mineral material through the Holocene. New and previously-published data show that the boundary between broadleaf forest and steppe occupied a similar position to present during the period 7000–4800 cal year BP, despite a warmer and drier climate, but shifted to the south following climate cooling and an increase in precipitation from 4800–2500 cal year BP. A subsequent decline in woodland cover was caused by both climate change and human impacts, with human activity becoming increasingly significant over the last two millennia. Prior to major human disturbance (about 1700 cal year BP) the landscape was dominated by mixed broadleaf-pine forests with some spruce covering about 60 % of the study area. Our results emphasize the variability of steppe-forest habitats over long time periods and the need to consider human impacts and climate change when setting targets for habitat conservation.