Poor Fen Research Articles

A hierarchical, multi‐sensor framework for peatland sub‐class and vegetation mapping throughout the Canadian boreal forest

AbstractPeatlands in the Canadian boreal forest are being negatively impacted by anthropogenic climate change, the effects of which are expected to worsen. Peatland types and sub‐classes vary in their ecohydrological characteristics and are expected to have different responses to climate change. Large‐scale modelling frameworks such as the Canadian Model for Peatlands, the Canadian Fire Behaviour Prediction System and the Canadian Land Data Assimilation System require peatland maps including information on sub‐types and vegetation as critical inputs. Additionally, peatland class and vegetation height are critical variables for wildlife habitat management and are related to the carbon cycle and wildfire fuel loading. This research aimed to create a map of peatland sub‐classes (bog, poor fen, rich fen permafrost peat complex) for the Canadian boreal forest and create an inventory of peatland vegetation height characteristics using ICESat‐2. A three‐stage hierarchical classification framework was developed to map peatland sub‐classes within the Canadian boreal forest circa 2020. Training and validation data consisted of peatland locations derived from various sources (field data, aerial photo interpretation, measurements documented in literature). A combination of multispectral data, L‐band SAR backscatter and C‐Band interferometric SAR coherence, forest structure and ancillary variables was used as model predictors. Ancillary data were used to mask agricultural areas and urban regions and account for regions that may exhibit permafrost. In the first stage of the classification, wetlands, uplands and water were classified with 86.5% accuracy. In the second stage, within the wetland areas only, peatland and mineral wetlands were differentiated with 93.3% accuracy. In the third stage, constrained to only the peatland areas, bogs, rich fens, poor fens and permafrost peat complexes were classified with 71.5% accuracy. Then, ICESat‐2 ATL08 spaceborne lidar data were used to describe regional variations in peatland vegetation height characteristics and regional and class‐wise variations based on a boreal forest wide sample. This research introduced a comprehensive large‐scale peatland sub‐class mapping framework for the Canadian boreal forest, presenting the first moderate resolution map of its kind.

The impact of drying on the structure and photosynthesis of boreal peatland vegetation

Boreal peatlands harbour large stores of carbon as peat below their surfaces. Climate change is expected to cause drying in northern peatlands, which will in turn impact the carbon balance of these ecosystems that is maintained by high water tables and the hydrologically sensitive plants growing there. This study aims to quantify how vegetation will be structured (I) and photosynthesize (II, III) in a future climate as emulated by long-term water level drawdown (WLD). To do this, changes in the vegetation and its photosynthesis after WLD are linked, and the response of Sphagnum mosses to periodic drought is investigated. Field measurements were done at a long-term WLD field experiment that contained a rich (mesotrophic) fen, a poor (oligotrophic) fen and a bog (ombrotrophic) site. Measurements included vegetation surveys from existing permanent sample plots and leaf-level carbon dioxide exchange measurements. For an experiment in controlled conditions peatland surface cores from this field experiment were transported to a greenhouse where the photosynthesis of lawn Sphagna during and after an experimental periodic drought was measured. The field study revealed that the response of peatland vegetation to WLD depend on peatland type. The species composition in the rich fen was the most impacted by WLD, while the bog vegetation demonstrated stability. Similarly, large increases in photosynthesis occurred following WLD on the vascular plant-covered rich fen, while changes were negligible on the Sphagnum-carpeted bog. The vegetation on the two fens shifted from an open sedge-, or sedge and Sphagnum-dominated ecosystem, to a tree-dominated ecosystem. Canopy development following WLD further accelerated vegetation changes by shading and sheltering the understorey vegetation. Vascular plants were the most likely to increase productivity from WLD as they are best suited to utilize the nutrients made available by peat mineralization, while Sphagnum moss photosynthesis was impacted little. The greenhouse study revealed that lawn Sphagnum mosses exposed to long-term WLD were more vulnerable to drought compared to those from wet sites. Large capitula typical to fen Sphagnum species appeared to be beneficial for surviving periodic drought. This work demonstrated that climate change as emulated by long-term WLD will have a large impact on the vegetation composition of northern peatlands and increase photosynthetic function of these ecosystems, fens in particular. To better predict climate feedbacks from these changes, carbon dynamics including peatland vegetation dynamics should be updated in global process models. Future research to better understand the tipping point of different peatland types after WLD in different climatic regions will help us to predict changes in these diverse and globally important systems.

From shady ditches to artificial pools – Does mire restoration benefit aquatic invertebrates?

To combat the loss of wetlands and the services they provide, many are now being restored. Rewetting, usually by ditch blocking, is a common approach to restore drained wetlands, where it can create a supply of permanent artificial pools. We studied how aquatic macroinvertebrate abundance, species richness and communities respond to ditch blocking, and how the new lentic waterbodies contribute to the habitat value of these ‘restored’ ecosystems. The study system was a large before-after-control-impact (BACI) experiment along forested mixotrophic bog edges, where we sampled macroinvertebrates prior to and after the restoration that had created a total of 308 individual pools along former ditch channels. The mean abundance and taxon richness increased similarly in drain-blocked and control ditches between 2015 and 2021 but blocked and control ditches started to host distinct communities. Most pronounced changes were the decrease in the numbers of bivalves and plecopterans and the appearance of vagile species, such as odonatans, hemipterans and certain beetles and flies to blocked ditches, including several characteristic species. Overall, the restoration provided new habitats for aquatic macroinvertebrates, but the convergence of these communities toward natural transitional mire communities remains to be studied.

Recovery of Smelter-Impacted Peat and Sphagnum Moss: a Microbial Perspective.

Peatlands store approximately one-half of terrestrial soil carbon and one-tenth of non-glacial freshwater. Some of these important ecosystems are located near heavy metal emitting smelters. To improve the understanding of smelter impacts and potential recovery after initial pollution controls in the 1970s (roughly 50 years of potential recovery), we sampled peatlands along a distance gradient of 134 km from a smelter in Sudbury, Ontario, Canada, an area with over a century of nickel (Ni) and copper (Cu) mining activity. This work is aimed at evaluating potential shifts in bacterial and archaeal community structures in Sphagnum moss and its underlying peat within smelter-impacted poor fens. In peat, total Ni and Cu concentrations were higher (0.062-0.067 and 0.110-0.208 mg/g, respectively) at sites close to the smelter and exponentially dropped with distance from the smelter. This exponential decrease in Ni concentrations was also observed in Sphagnum. 16S rDNA amplicon sequencing showed that peat and Sphagnum moss host distinct microbiomes with peat accommodating a more diverse community structure. The microbiomes of Sphagnum were dominated by Proteobacteria (62.5%), followed by Acidobacteria (11.9%), with no observable trends with distance from the smelter. Dominance of Acidobacteria (32.4%) and Proteobacteria (29.6%) in peat was reported across all sites. No drift in taxonomy was seen across the distance gradient or from the reference sites, suggesting a potential microbiome recovery toward that of the reference peatlands microbiomes after decades of pollution controls. These results advance the understanding of peat and Sphagnum moss microbiomes, as well as depict the sensitivities and the resilience of peatland ecosystems.

Water level drawdown makes boreal peatland vegetation more responsive to weather conditions.

Climate warming and projected increase in summer droughts puts northern peatlands under pressure by subjecting them to a combination of gradual drying and extreme weather events. The combined effect of those on peatland functions is poorly known. Here, we studied the impact of long-term water level drawdown (WLD) and contrasting weather conditions on leaf phenology and biomass production of ground level vegetation in boreal peatlands. Data were collected during two contrasting growing seasons from a WLD experiment including a rich and a poor fen and an ombrotrophic bog. Results showed that WLD had a strong effect on both leaf area development and biomass production, and these responses differed between peatland types. In the poor fen and the bog, WLD increased plant growth, while in the rich fen, WLD reduced the growth of ground level vegetation. Plant groups differed in their response, as WLD reduced the growth of graminoids, while shrubs and tree seedlings benefited from it. In addition, the vegetation adjusted to the lower WTs, was more responsive to short-term climatic variations. The warmer summer resulted in a greater maximum and earlier peaking of leaf area index, and greater biomass production by vascular plants and Sphagnum mosses at WLD sites. In particular, graminoids benefitted from the warmer conditions. The change towards greater production in the WLD sites in general and during the warmer weather in particular, was related to the observed transition in plant functional type composition towards arboreal vegetation.

Distribution of grouse and their predators in peatland forest landscapes: A case for ecological integrity

Natural peatland forest landscapes have been transformed and fragmented by forestry and agriculture worldwide, which undermines their ecological functioning and resilience. In Northern Europe, such transformations are apparently linked with observed long-term declines of forest dwelling grouse; those declines have not been effectively addressed by conservation. We asked how site factors, in combination with forest management and predation risk, shape grouse distributions in such landscapes in the breeding season. The data were collected by single-visit snapshot mapping of the capercaillie (Tetrao urogallus), black grouse (Lyrurus tetrix), hazel grouse (Tetrastes bonasia), and the signs of their potential predators across seven peatland forest areas (156 km2 in total) around large bogs in Estonia. We modelled the presence of grouse species in relation to landscape gradients, forest stand characteristics, and predator occurrence. The species were partly segregated along the bog-fen forest gradient (on different types of peat soils) and by stand composition; most capercaillie hens dispersed up to 2.5 km from lekking sites. All species avoided recently thinned forests, except breeding capercaillie in transitional mire sites (their preferred habitat). When the other factors were accounted for, the grouse neither avoided densely ditched areas nor predator vicinity at a forest scale (ca. 20-ha), which may expose the birds to unperceived risks. Our results indicate that conserving all three grouse species in peatland forest landscapes requires maintaining the edaphic and stand-structural diversity of the forests. Frequent thinning and dense predator populations are detrimental, and may require large refuge habitats to buffer their influence. Sustaining viable grouse populations serves as a clear target for ecosystem management in drained peatland landscapes.

A Voucher Flora of Diatoms from Fens in the Tanana River Floodplain, Alaska.

Climate change and human activities may alter the structure and function of boreal peatlands by warming waters and changing their hydrology. Diatoms can be used to assess or track these changes. However, effective biomonitoring requires consistent, reliable identification. To address this need, this study developed a diatom voucher flora of species found across a boreal fen gradient (e.g., vegetation) in interior Alaskan peatlands. Composite diatom samples were collected bi-weekly from three peatland complexes over the 2017 summer. The morphological range of each taxon was imaged. The fens contained 184 taxa across 38 genera. Eunotia (45), Gomphonema (23), and Pinnularia (20) commonly occurred in each peatland. Tabellaria was common in the rich and moderate fen but sparse in the poor fen. Eunotia showed the opposite trend. Approximately 11% of species are potentially novel and 25% percent matched those at risk or declining in status on the diatom Red List (developed in Germany), highlighting the conservation value of boreal wetlands. This voucher flora expands knowledge of regional diatom biodiversity and provides updated, verifiable taxonomic information for inland Alaskan diatoms, building on Foged's 1981 treatment. This flora strengthens the potential to effectively track changes in boreal waterways sensitive to climate change and anthropogenic stressors.

Fungal troublemakers – using indicator species with ephemeral fruitbodies to evaluate recovery of formerly extracted raised bogs

Including fungi into nature conservation research allows for a more comprehensive view of habitat quality thanks to their unique role in ecosystems. However, a broad application of fungi as indicators is limited mainly by the ephemeral occurrence of their fruitbodies and insufficient knowledge of their ecology. To overcome these limitations, we searched for fruitbodies of selected fungal peatland indicator species (Arrhenia bigelowii, A. gerardiana, A. telmatiaea, Cortinarius chrysolitus, C. davemallochii and Galerina hybrida) in various raised bogs and transitional mires (61 localities, 144 collections) in a wide area around disturbed, industrially harvested raised bogs under restoration. We aim to verify whether these species could be detected by routine environmental sequencing (eDNA), and to assess their habitat requirements by analysing the vegetation around fruitbodies and fungal communities under them. Generally, the studied fungal indicator species preferred sites where peatland specialist plants occurred. Vegetation survey and eDNA highlighted a broad ecological niche of Galerina hybrida across peatlands and a preference of Cortinarius chrysolitus for transitional mires. Because the eDNA approach sometimes failed to detect these species even under their fruitbodies (14% of samples), and these species tend to occur rarely and patchily in their habitats, we subsequently selected eight co-occurring vascular plant species, four co-occurring bryophyte species and 23 co-occurring fungal OTUs (operational taxonomic units) which were significantly associated with the studied fungal indicator fruitbodies, possibly indicating potentially suitable conditions for them. The information obtained from eDNA of fungi is still difficult to interpret because many unknown OTUs were detected in the datasets. Nevertheless, similarly to the co-occurring plant species, the presence of the co-occurring fungal OTUs was significantly higher in undisturbed raised bogs than in the disturbed ones. This approach may predict the occurrence of fungal indicator species in the absence of their fruitbodies or when environmental sequencing fails to detect their DNA. This method can be applied to more effectively monitor the restoration success in peatlands.

Diatom evidence for late Holocene environmental change in a permafrost peatland in the northern Greater Khingan Mountains, Northeast China

High-latitude permafrost peatlands are sensitive to global warming, and understanding their paleohydrological evolution is critical for assessing future hydrological and environmental changes. This paper presents a diatom record from a peat deposit covering the past 3300 years to reconstruct the moisture and acidity conditions in the Tuqiang permafrost peatland in the northern Greater Khingan Mountains of northeast China. Our findings are integrated with previously published records of plant macrofossils, palynology, and geochemistry from the same profile. From 3300 to 2800 cal yr BP, planktonic and benthic diatoms were equally abundant, indicating relatively high moisture conditions, while the low abundance of acidophilous diatoms reflects relatively high pH during this interval. Pollen data show dominance by sedges with input from the surrounding Pinus forest, while LOI data and lithology suggest that the site was a non-peat accumulating wetland. During the period 2800–1100 cal yr BP, the dominance of planktonic diatoms indicates a wetter local environment, concurrent with the dominance of peat-forming sedges (Eriophorum), indicating the development of a peatland. Between 1100 and 500 cal yr BP, a short-lived increase in acidophilous diatoms (Eunotia) marks a decrease in pH. Since 500 cal yr BP, the dominance of benthic diatoms reflects a drier environment, while a vegetation shift from an Eriophorum-dominated rich fen to a Sphagnum- and Ericaceae-dominated poor fen. An increase in Eunotia diatoms prior to the Sphagnum peak may indicate that diatoms are more sensitive to local acidified habitats than moss. Peatland development in the northern Greater Khingan Mountains was likely induced by the onset of a cooler and wetter climate starting at approximately 2800 cal yr BP, a scenario supported by regional paleoclimate records. Since 700 cal yr BP, the peatland has been affected by both anthropogenic activities and climatic changes, as a drying climate and intensified human activities around the study area reduced diatom species diversity and peat accumulation. Under the background of future global warming and enhanced human activities, the decreasing species diversity and carbon accumulation rate of peatlands in high-latitude permafrost regions need more attention.

Landscape fires disproportionally affect high conservation value temperate peatlands, meadows, and deciduous forests, but only under low moisture conditions

Landscape fires are a natural component of the Earth System. However, they are of growing global concern due to climate change exacerbating their multiple impacts on biodiversity, ecosystems, carbon storage, human health, economies, and wider society. Temperate regions are predicted to be at greatest risk of increasing fire activity due to climate change, where fires can seriously impact important ecosystems for biodiversity and carbon storage, such as peatlands and forests. There is insufficient literature on the background prevalence, distribution, and drivers of fires in these regions, especially within Europe, to assess and mitigate their risks. Using a global database of fire patches based on the MODIS FireCCI51 product, we address this knowledge gap by quantifying the current prevalence and size of fires in Polesia, a 150,000 km2 area comprising a mosaic of peatland, forest, and agricultural habitats in northern Ukraine and southern Belarus. Between 2001 and 2019, fires burned 31,062 km2 of land, and were most frequent in spring and autumn. Although most fires started in agricultural land, fires disproportionately affected natural and semi-natural land cover types, particularly in protected areas. Over one fifth of protected land burned. Coniferous forests were the most common land cover type in protected areas, but fires mostly occurred in meadows, open peatlands (especially fen and transition mires), and native deciduous forests. These land cover types were highly susceptible to fires under low soil moisture conditions, but the risk of fire was low under average or higher soil moisture conditions. Restoring and maintaining natural hydrological regimes could be an effective nature-based solution to increase the resilience of fire-vulnerable ecosystems and support global biodiversity and carbon storage commitments under the United Nations Framework Conventions on Climate Change and Convention on Biological Diversity.

Trees in the Stream: Determining Patterns of Terrestrial Dissolved Organic Matter Contributions to the Northeast Pacific Coastal Temperate Rainforest

AbstractDissolved organic matter (DOM) composition in small watersheds depends on complex antecedent conditions that ultimately influence DOM generation, processing, and stability downstream. Here, we used ultrahigh resolution Fourier‐transform ion cyclotron resonance mass spectrometry and total dissolved nitrogen and dissolved organic carbon concentrations to investigate how DOM is produced in distinct sub‐catchment types (poor fen, forested wetland, and upland forest) and transported through a watershed in the northeast Pacific coastal temperate rainforest (NPCTR). We traced a suite of previously identified source‐specific marker formulae from vegetation and soil downstream and used them to test models of terrestrial DOM inputs. Marker formulae escaped microbial degradation and were exported from the watershed, demonstrating strong land‐to‐ocean connectivity through the transfer of unmodified tree DOM from specific tree species into the marine environment. Simple hydrologic and temperature variables were better able to predict inputs of soil‐sourced DOM into the stream network than tree‐sourced DOM, highlighting the role of antecedent conditions (e.g., plant growth stage) in DOM source availability and hydrologic flow connectivity, particularly for plant‐derived material. Forested wetland pore waters featured thousands of nitrogen‐containing molecular formulae that potentially provide a path of direct organic nitrogen uptake to organisms. The modified aromaticity index peaked in midsummer (up to 0.55 for fen headwaters) suggesting DOM inputs from freshly produced vegetation provide a strong summertime terrestrial signal. As the climate changes, new watershed‐scale conditions may further complicate predictions of DOM source availability, flow connectivity, and downstream fate in NPCTR watersheds.

Nitrogen addition mediates monospecific and mixed litter decomposition in a boreal peatland

Litter decomposition is a key determinant of soil organic matter accumulation in boreal peatlands. Climate warming and atmospheric nitrogen (N) deposition have recently increased N availability in boreal peatlands. However, how increased N availability alters decomposition dynamics of plant litter is uncertain in these ecosystems, especially for litter mixtures. Here, we collected fresh litter of four common species (Betula fruticosa, Ledum palustre, Eriophorum vaginatum, and Sphagnum palustre) in a poor fen of northeast China, and established an N addition (6 g N m−2 year−1) experiment to assess the effect of increased N availability on monospecific and mixed litter decomposition in the hummocks and hollows after one and three years of decomposition. In both hummocks and hollows, N addition increased mass loss of four monospecific litter after one year of decomposition but only accelerated litter decomposition of E. vaginatum and S. palustre with low litter quality after three years of decomposition. Moreover, N addition effects on monospecific litter decomposition were negatively related to monospecific litter decomposition in the absence of N addition. Irrespective of decomposition position, additive effects were more frequent than synergistic effects during decomposition of litter mixtures. In addition, N addition generally changed synergistic effects to additive effects after one and three years of decomposition, and such changing trends were stronger in hummocks than in hollows. These observations suggest that litter quality mediates N addition effects on monospecific litter decomposition, and highlight that increased N availability will alter mixed litter decomposition by reducing synergistic effects in boreal peatlands.

Notes on distribution and habitat preferences of Sphagnum inexspectatum and S. mirum in Western Siberia

New records of two rare moss species, Sphagnum inexspectatum Flatberg (4) and S. mirum Flatberg & Thingsgaard (9) are reported from Western Siberia, and discuss them in context of their habitat preferences in region as well as general range. Their distribution in Russia is considered and re-assessed. Geobotanical relevés of plant communities with Sphagnum inexspectatum and S. mirum from Western Siberia are presented. It is shown that in the taiga zone S. inexspectatum occurence is closely related to communities of the alliance Stygio-Caricion limosae Nordhagen 1943, class Scheuchzerio-Caricetea nigrae Tx. 1937, and similar Sphagnum carpets in meso-oligotrophic mires, where it grows as single stems among other peat mosses in poor conditions on slightly acidic substrates. In forest tundra and southern tundra this species occurs only in communities of the alliance Caricion stantis Matveyeva 1994. More diverse communities with S. mirum are assigned mainly to the alliance Sphagno-Caricion canescentis Passarge (1964) 1978, which comprises sedge-Sphagnum vegetation located in fens and transitional bogs in a wide variety of habitats from moderately poor to moderately rich in mineral nutrients and with slightly acidic substrate. This species occurs both with low (as single stems) and high abundance (frequently being dominant) in moss layer.

Microbial communities and biogeochemical functioning across peatlands in the Athabasca Oil Sands region of Canada: Implications for reclamation and management

AbstractPeatlands play an important role in global biogeochemical cycles and are essential for multiple ecosystem functions. Understanding the environmental drivers of microbial functioning and community structure can provide insights to enable effective and evidence‐based management. However, it remains largely unknown how microbial diversity contributes to the functioning of belowground processes. Addressing this gap in knowledge will provide a better understanding of microbial‐mediated processes in peatlands that are undergoing restoration or reclamation. This study assessed the changes in microbial community diversity and structure as well as soil function by measuring microbial respiration on a range of substrates from three natural fen types found in the Athabasca Oil Sands region of Alberta, Canada (a poor fen, a hypersaline fen, and a tree‐rich fen) and a nearby constructed fen undergoing reclamation following open pit mining. Overall, substrate induced respiration was significantly higher in the constructed fen. Alpha diversity of fungi and prokaryotes was highest in the tree‐rich fen, and the composition of microbial communities was significantly different between fens. Both fungal and prokaryotic communities were strongly related to pore water pH and temperature, with plant richness also contributing to the shape of fungal communities. In summary, microbial community structure reflects the underlying differences in soil condition across different fens but plays essential roles in the ecological functions of soil. These findings provide a new outlook for the management of peatlands undergoing post‐mining reclamation. Future research on peatland reclamation should consider the dynamic interaction between communities and ecosystem functionality, for which this study forms a useful baseline.

Biotic and Abiotic Control Over Diurnal CH4 Fluxes in a Temperate Transitional Poor Fen Ecosystem

To understand the variability of methane (CH4) fluxes between a temperate mid-altitude Sphagnum-dominated peatland and the atmosphere, we monitored simultaneously eddy covariance, hydrometeorological and physical parameters between April 2019 and December 2021. The site was a CH4 source for the atmosphere, with a cumulative emission of 23.9 ± 0.6 g C m−2 year−1. At the interannual scale, deeper water table during vegetation growth periods resulted in lower CH4 fluxes (FCH4), and reciprocally. Furthermore, the seasonal temperature variation in the anaerobic peat layer was a good predictor for FCH4. However, while the lowest temperatures occurred between December and February, the lowest FCH4 were observed between March and May, with around 30% of negative FCH4. Indeed, the fastest increase in temperature of the aerobic layer likely stimulated methanotrophy at the expense of methanogenesis. Negative FCH4, systematically observed at midday, were concurrent with high photon flux densities, latent heat fluxes and net negative ecosystem CO2 exchanges, suggesting the control of photosynthesis over CH4 oxidation. Moreover, our results highlighted marked diurnal cycles with FCH4 maximal at night and minimal at midday for all seasons. This diurnal cyclicity is in opposition to what is typically known for peatlands dominated by vascular plants. Physical parameters, such as soil surface temperature and sensible heat fluxes, likely contribute to this diurnal FCH4 cyclicity and require further investigation. Our study thus demonstrates that diurnal variations in FCH4 must be considered before upscaling to seasonal or annual cycles, along with the effect of vegetation on CH4 transfer and oxidation processes.

Variation in carbon and nitrogen concentrations among peatland categories at the global scale.

Peatlands account for 15 to 30% of the world's soil carbon (C) stock and are important controls over global nitrogen (N) cycles. However, C and N concentrations are known to vary among peatlands contributing to the uncertainty of global C inventories, but there are few global studies that relate peatland classification to peat chemistry. We analyzed 436 peat cores sampled in 24 countries across six continents and measured C, N, and organic matter (OM) content at three depths down to 70 cm. Sites were distinguished between northern (387) and tropical (49) peatlands and assigned to one of six distinct broadly recognized peatland categories that vary primarily along a pH gradient. Peat C and N concentrations, OM content, and C:N ratios differed significantly among peatland categories, but few differences in chemistry with depth were found within each category. Across all peatlands C and N concentrations in the 10-20 cm layer, were 440 ± 85.1 g kg-1 and 13.9 ± 7.4 g kg-1, with an average C:N ratio of 30.1 ± 20.8. Among peatland categories, median C concentrations were highest in bogs, poor fens and tropical swamps (446-532 g kg-1) and lowest in intermediate and extremely rich fens (375-414 g kg-1). The C:OM ratio in peat was similar across most peatland categories, except in deeper samples from ombrotrophic tropical peat swamps that were higher than other peatlands categories. Peat N concentrations and C:N ratios varied approximately two-fold among peatland categories and N concentrations tended to be higher (and C:N lower) in intermediate fens compared with other peatland types. This study reports on a unique data set and demonstrates that differences in peat C and OM concentrations among broadly classified peatland categories are predictable, which can aid future studies that use land cover assessments to refine global peatland C and N stocks.

Préférences des fourmis en matière de type et de structure d’habitat : résultats sur quatre tourbières d’Auvergne (Hymenoptera : Formicidae)

Habitat type and structure preferences in ants: results from four peat bogs in Auvergne (Hymenoptera: Formicidae). - The link between habitats and ants was studied in the Parc naturel régional des Volcans d’Auvergne to understand better the ecological conditions favorable to the species. The study area was composed of four peat bogs in the Puy-de-Dôme. The method consisted in the description of the habitat (type and structure) and the inventory of ants by baits within 1149 plots of 16 m2. The analyses highlight links between habitat and myrmecofauna within these peat bogs. The species concerned are Formica picea Nylander, 1846, Formica lemani Bondroit, 1917, Lasius platythorax Seifert, 1991, Myrmica ruginodis Nylander, 1846 and Myrmica scabrinodis Nylander, 1846. The bibliographic elements concerning the ecological preferences of the different species are globally confirmed. Formica picea and Myrmica scabrinodis are particularly associated with raised bog habitats with a low vegetation structure. Formica lemani is found almost exclusively in mesophilic grasslands where it prefers higher vegetation. Lasius plathythorax is found in raised bog and low marsh habitats and transitional bogs in particular, with low vegetation. Only Myrmica ruginodis is favored by tall vegetation structures and preferentially frequents molinia and megaphorbia.

Transitional mire vegetation restoration: changing failure back to success, case study from Slovenia

In this article, we describe two restoration efforts (raising and lowering the water table) in a transitional mire and use vegetation survey data (from 1987, 1999, and 2015) to evaluate restoration success. We used historical and current vegetation relevés and vegetation maps to identify target plant communities and track changes in vegetation over time. Ordination plot (NMDS) and the Sankey diagram were used to detect changes in plant community composition and overall vegetation. The first restoration (1993) was not planned according to the standards and was unsuccessful because of a very rapid rise in the water level. It caused the destruction of bog and mire plant communities and the emergence of new wetland stands. Subsequent restoration (in 2000), with a gradual lowering of the water table, allowed natural restoration of mire communities, but certain species remain absent. Our study demonstrated the importance of careful restoration planning, selection of target plant communities, and the importance of vegetation survey for monitoring.

Common Bryophytes from the Sax-Zim Bog Important Bird Area in St. Louis County, Minnesota

We identified 68 bryophytes (4 liverworts, 64 mosses) during three days of sampling five Friends of Sax-Zim Bog (FOSZB) properties and five additional sites within the surrounding 147,000-acre Sax-Zim Bog Important Bird Area in St. Louis County, Minnesota. The landscape types surveyed are loosely categorized as upland, forested wetland, moderate-rich fen, poor fen, restored fen and bog. In total, this survey added 50 species (3 liverworts, 47 mosses) to a previous FOSZB bryophyte species list for a total of 78 bryophyte species (4 liverworts, 74 mosses) documented in the greater Sax-Zim Bog region. Over 20% of the bryophytes found were in the genus Sphagnum. Our updated list of common bryophytes will be used by FOSZB staff for educational purposes to inform FOSZB visitors about local bryoflora.

Fen development along the southern shore of Lake Ontario

Fen development along a drowned-river-mouth tributary to Braddock Bay, Lake Ontario was studied to address its formation. Nested piezometers were installed to assess groundwater contributions and obtain water chemistry samples. Soil and geology information came from existing sources. We converted paleo lake levels from published reports to IGLD1985 and calendar years BP for use in analyzing vegetation changes over time using a combination of peat-core plant macrofossils and modern surveys. Piezometer data showed upward discharge, water at 3-m depth had pH 6.9, specific conductivity of 508 µS/cm, and alkalinity 206 mg/L as CaCO3. Hydraulic head and mineralized water chemistry decreased at shallower depths. Vegetative development began 1790 cal yr BP with sedges and brown moss when land surface was 0.135 m above lake level. Lake levels increased, and by 1590 cal yr BP, water was 0.17 m deep and sedges were joined by shoreline emergent species. Water depth then increased to 0.525 m but began decreasing as lake levels fell. Peatland species appeared around 810 cal yr BP when water depth was reduced to 0.225 m. About 585 cal yr BP, additional peatland species appeared when land surface was 0.075 m above lake level. Sphagnum became prominent 80 cal yr BP (0.81 m above lake level), representing 67 % mean cover in modern vegetation. Isolation of the surface from calcareous groundwater resulted in transition from rich fen to poor fen. These wetlands are rare in the lower Great Lakes and deserve protection of their characteristic hydrology, water chemistry, and vegetation structure.