Fen Areas Research Articles

Disaggregating the Carbon Exchange of Degrading Permafrost Peatlands Using Bayesian Deep Learning

AbstractExtensive regions in the permafrost zone are projected to become climatically unsuitable to sustain permafrost peatlands over the next century, suggesting transformations in these landscapes that can leave large amounts of permafrost carbon vulnerable to post‐thaw decomposition. We present 3 years of eddy covariance measurements of CH4 and CO2 fluxes from the degrading permafrost peatland Iškoras in Northern Norway, which we disaggregate into separate fluxes of palsa, pond, and fen areas using information provided by the dynamic flux footprint in a novel ensemble‐based Bayesian deep neural network framework. The 3‐year mean CO2‐equivalent flux is estimated to be 106 gCO2 m−2 yr−1 for palsas, 1,780 gCO2 m−2 yr−1 for ponds, and −31 gCO2 m−2 yr−1 for fens, indicating that possible palsa degradation to thermokarst ponds would strengthen the local greenhouse gas forcing by a factor of about 17, while transformation into fens would slightly reduce the current local greenhouse gas forcing.

Wetland Poetics: Regional-Situatedness as Planetary Practice

Public debates around the current environmental crisis in Latin America have made clear that certain ecosystems are perceived as more charismatic than others. The Amazon Rainforest and Glaciers of Patagonia receive much more research attention and policy coverage than, say, the wetlands of the Paraná Delta River. Perhaps some of wetlands’ lesser public appeal can be attributed to their conceptual indeterminacy. In 1971, the Wetland Convention of Ramsar in Iran defined wetlands as “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters” (“Article 1”). Despite this slippery definition, which we could generally sum up as areas flooded either temporarily or permanently, wetlands are an integral part of the natural systems that make life on earth possible: not only do they serve as fresh water reservoirs, 40% of the world’s biodiversity lives or reproduces on them (“Cambio climático”). Crucially, wetlands cushion the impacts of rain and store more carbon than any other ecosystem, allowing them to function as great purifying filters and making them important allies in the fight against climate change.

Population demography of rare sedges (Eriophorum gracile and Carex livida) north of the Arctic Circle in Murmansk Region and climate change impacts

Species of Cyperaceae are little studied on the population level globally. Also in Murmansk Region, species from this family were not included in long-term population studies of rare plant species whereas other representatives from 21 families were put in [Blinova, 2009]. Experimental works with sedges is often neglected because of taxonomic difficulties and a lack of methods for study populations of this group [Kitamura et al., 2016; Sosnovska, Danylyk, 2017]. Such difficulties became obvious while the IUCN-red data book testing. Of rare sedges studied in this paper Eriophorum gracile is included in the regional Red data book [Kozhin, 2014] and Carex livida is in the Appendix of this book in the group Need of monitoring. 
 
 The Murmansk Region (6670 N), located in the north-eastern corner of Russian Fennoscandia, is a part of the Atlantic-Arctic zone of temperate belt with a rather mild climate. The region is very heterogeneous. Two latitudinal vegetation zones can be distinguished: tundra and taiga. So, many boreal plant species reach here their northern limit of distribution. Our field work has been conducted in the center part of the region in a recently found rich fen [Blinova, Petrovskij, 2014]. Both study species (Eriophorum gracile и Carex livida) have circumpolar distribution in wetlands of northern hemisphere [Hulten, Fries, 1986], and they are at the northern range in Murmansk Region [Kuzeneva, 1954; Chernov, 1954]. They are polycarpic perennials. An annual shoot has been selected as a counting unit (Fig. 1). In E. gracile only the number of generative shoots has been counted in the field. For non-destructive purposes, from herbarium data, the ratio between generative and vegetative shoots was defined as 1:1. The total population size for this species has been estimated from this ratio. In population of C. livida, the direct counting in the field has been done on 3-5 small plots (0.25*0.25 м2). Lately this value has been recalculated according to the area of population subset. Clusters and subsets have been distinguished in population structure according to suggested aggregation patterns of spatial structure in local plant populations [Blinova, 2018]. Marked population subsets have been monitored several times in the growing period in 2014-2016 years. In the field the boundaries and areas of rich fen and populations (including subsets) have been estimated with the help of GPS navigation device Garmin Dakota 20, in the lab all data are further processed using Garmin Software BaseCamp 4.2.5. Nomenclature for vascular plants is given according to S. K. Czerepanov [1995], for mosses after M. S. Ignatov O. M. Afonina [1992]. 
 
 Our results show that extremely low (0.2% for Eriophorum gracile) and relatively low (3.1% для Carex livida) population cover is characteristic for a large long-term monitored fen. Spatial aggregation of E. gracile population is structured on very small area (40 м2) whereas C. livida is established on relatively representative area (633 м2). E. gracile develops small population subsets (8 m2 on average) at a distance to next about 70 m in different parts of rich fen. Each such subset contains 9-10 mature individuals on average. C. livida has larger subsets (211 m2 on average) at 30 m away from the neighbor. The size of each subset makes c. 2500 generative shoots. The spatial population pattern of E. gracile shows isolated subsets with single clusters, whereas of C. livida represents isolated subsets with merged clusters. High fluctuations of population size and its subsets are revealed in E. gracile from year to year. The number of generative shoots and air temperature in the growing season (June-September) of the current year establish negative relationship.
 
 This study in one of the northernmost populations of Eriophorum gracile confirms other data from different parts of its distribution area that populations of this species are very fragmented and show high fluctuations in the number of generative shoots [Barr 1996; Ksermann, Moser, 1999; Dickenmann, Keel, 2004; Decker et al., 2006; Chatters, Sanderson, 2014]. An analysis of spatial structure of populations has been pointed out that anemochory of E. gracile could be a bottleneck for the population fitness in rich fens conditions, whereas baro- and hydrochory of C. livida promotes further seed germination and survival. Additionally, current climate-changed impacts could cause an extirpation of E. gracile from floristic composition of rich fens, whereas such a threat is minimal for C. livida. Both species need regional protection of their populations. An introduction into culture is essential for further ontogenetic studies and trigger examination of clonal division of labor.

Оценка эволюции ландшафтов Cамотлорского нефтегазового месторождения

The Samotlor oil and gas field in Western Siberia, one of the largest in the world in terms of oil reserves, has been developed since 1969. Natural forest and marsh landscapes are experiencing the strongest anthropogenic pressure due to the creation of a dense network of cluster drilling sites, roads connecting them with pipelines, enterprises for primary oil refining, lines of communication. Oil production and transportation activities during the development of the Samotlor field are accompanied by pollution of the territory and degradation of vegetation, and a reduction in forest areas. To identify the dynamics of natural forest-bog landscapes, which manifests itself in a change in the ratio of forest and swamp areas, we used a comparison of a survey topographic map at a scale of 1:200 000 in 1980, showing the distribution of forests, as well as passable and impenetrable swamps, with modern high-resolution satellite images, according to which deciphered the boundaries of forests and various types of swamps-raised ridge-hollow, ridge-lake-hollow and lowland. Comparison of materials from different times was carried out on a 7.5×13.5 km site southeast of Lake Samotlor. A comparison of maps compiled in 1980 and 2019 shows that the area of forests here has almost tripled; Herbaceous-shrub communities with small islands of residual forests formed on the site of reduced forest tracts. Among the swamps, a reduction in the areas of lowland fen was revealed, their localization along the shores of lakes, with the expansion of the areas of raised bogs. In place of the impenetrable swamps of 1980, ridge-lake-hollow complexes of raised bogs were formed, with wide distribution of ridge-hollow. It has been shown that, along with the negative processes of anthropogenic deforestation, ecosystem pollution and vegetation degradation, during the development of the deposit there is an increase in the drainage of the territory, accompanied by a local increase in greenery, which is additionally promoted by the tendency to climate warming.

Recent Lateral Expansion of Sphagnum Bogs Over Central Fen Areas of Boreal Aapa Mire Complexes

We investigated recent changes in spatial patterning of fen and bog zones in five boreal aapa mire complexes (mixed peatlands with patterned fen and bog parts) in a multiproxy study. Comparison of old (1940–1970s) and new aerial images revealed decrease of flarks (wet hollows) in patterned fens by 33–63% in middle boreal and 16–42% in northern boreal sites, as lawns of bog Sphagnum mosses expanded over fens. Peat core transects across transformed areas were used to verify the remote sensing inference with stratigraphic analyses of macrofossils, hyperspectral imaging, and age-depth profiles derived from 14C AMS dating and pine pollen density. The transect data revealed that the changes observed by remote sensing during past decades originated already from the end of the Little Ice Age (LIA) between 1700–1850 CE in bog zones and later in the flarks of fen zones. The average lateral expansion rate of bogs over fen zones was 0.77 m y−1 (range 0.19–1.66) as estimated by remote sensing, and 0.71 m y−1 (range 0.13–1.76) based on peat transects. The contemporary plant communities conformed to the macrofossil communities, and distinct vegetation zones were recognized as representing recently changed areas. The fen-bog transition increased the apparent carbon accumulation, but it can potentially threaten fen species and habitats. These observations indicate that rapid lateral bog expansion over aapa mires may be in progress, but more research is needed to reveal if ongoing fen-bog transitions are a commonplace phenomenon in northern mires.

Fifteen years of habitat, floristic and vegetation change on a pioneer sand-dune and slack system at Ainsdale, north Merseyside, UK

Changes in habitat, floristics and vegetation between 2005 and 2019 were studied on 2.9 ha of sandy foreshore near Ainsdale-on-Sea, north Merseyside. Named the ‘New Green Beach’, the site initially supported saltmarsh vegetation but, within five years, a 30-35 m-wide embryo dune ridge had formed, eventually 3.5 m high, backed by a 300 x 30 m seasonally flooded, calcareous dune-slack. The latter was colonised by pioneer slack plants, after which it rapidly developed areas of tall-herb fen and Alnus/Salix carr, while saltmarsh plants declined. During succession, species recorded as ‘rare’ became fewer in number while a higher frequency of ‘abundant’ taxa was recorded. The number of vascular plants listed annually increased from one in 2005 to 154 in 2019, though the rate of addition of new plants fell after 2010. Overall, 246 taxa were identified during the study. Only 9% of these were non-native, 17% being regionally or nationally notable, including 16 Red-listed species. Very poor statistical fits were obtained to recognised UK National Vegetation Classification vegetation types. Analysis of Ellenberg Indicator Values for salinity, nitrogen, moisture and reaction showed that the plant community became progressively adapted to low salinity, lower fertility, drier conditions and a less basic soil. The findings are discussed in relation to comparable studies elsewhere in Britain and Northern Europe. The rate of succession on the New Green Beach seems remarkably high, while evidence of declining soil fertility over time was unexpected.

A Landscape of Medieval Common Peat Fens: The Lower Witham Valley and Wildmoor, Lincolnshire (UK)

ABSTRACT The peat fen was viewed by landscape improvers of the seventeenth and eighteenth centuries as under-utilised land in need of improvement. Two contrasting areas of common peat fen in Lincolnshire are examined to test this contention. It is shown that by the twelfth and early thirteenth century these fens were closely managed. To prevent flooding the adjoining rivers the watercourses were canalised. Drainage channels were cut through the fen to remove water and embankments were constructed to constrain the rivers. Some permanent settlements were established by monasteries in the twelfth century to use the rich pasture for cattle grazing. Other areas were enclosed for meadowland. Instead of considering these as poorly used wetlands which could not be drained, it is argued that their usage was adapted to the different conditions within the peat fens and that this allowed a range of resources to be exploited.

A Simple Method for Simulating Groundwater Interactions with Fens to Forecast Development Effects

Protection of fens–wetlands dependent on groundwater discharge–requires characterization of groundwater sources and stresses. Because instrumentation and numerical modeling of fens is labor intensive, easy‐to‐apply methods that model fen distribution and their vulnerability to development are desirable. Here we demonstrate that fen areas can be simulated using existing steady‐state MODFLOW models when the unsaturated zone flow (UZF) package is included. In cells where the water table is near land surface, the UZF package calculates a head difference and scaled conductance at these “seepage drain” cells to generate average rates of vertical seepage to the land. This formulation, which represents an alternative to blanketing the MODFLOW domain with drains, requires very little input from the user because unsaturated flow‐routing is inactive and results are primarily driven by easily obtained topographic information. Like the drain approach, it has the advantage that the distribution of seepage areas is not predetermined by the modeler, but rather emerges from simulated heads. Beyond the drain approach, it takes account of intracell land surface variation to explicitly quantify multiple surficial flows corresponding to infiltration, rejected recharge, recharge and land‐surface seepage. Application of the method to a basin in southeastern Wisconsin demonstrates how it can be used as a decision‐support tool to first, reproduce fen distribution and, second, forecast drawdown and reduced seepage at fens in response to shallow pumping.

A Review on: The Importance, Distribution and Threat of Ethiopian Wetlands

Ethiopia, like as many countries in the world, has immense wetland resources. The wetlands in Ethiopia include many forms such as lakes, swamps, marshy wetlands, peat wetlands, flood plains, high mountain lakes, natural and manmade ponds. These wetlands have been contributing for the well-being of many Ethiopians for generations and still they are contributing and this will continue for years in the future. Wetlands, according to the Ramsar Convention are defined as “areas of marsh, fen, peat land or water as, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish, or salt including areas of marine water, the depth of which at low tide does not exceed six meters”. In Ethiopia there are large areas of wetlands which are distributed in various parts of the country almost all altitudinal ranges from lowland (the Dallol depression) up to top of high mountains. Wetlands are of enormous socioeconomic and environmental values and attract a number of users that get benefited directly or indirectly. They are source of water, food, reed, medicinal plants and other income generating activities for the rural community.Wetlands generally classified into 3 major classes: freshwater, saltwater and manmade wetlands According to the FAO in 1984, two types of wetlands (swamps and marshes) dominate in Ethiopia and some studies show that based on scattered information, wetlands are estimated to cover about 2% of the total land mass of the country. Though wetlands in the country is poorly studied and recorded more than 40 wetlands are identified as important bird areas for the nation, and these sites support some of the endemic bird life and biodiversity of Ethiopia. The main objective of this paper is to discuss the importance, distribution and threats to wetlands of Ethiopia. Keywords: Wetland, Ramsar convention, wetland management, threat DOI : 10.7176/JNSR/9-6-02 Publication date :March 31 st 2019

Hydrologic function of a moderate-rich fen watershed in the Athabasca Oil Sands Region of the Western Boreal Plain, northern Alberta

Peatlands are a dominant land feature in the Athabasca Oil Sands Region (AOSR) of the Western Boreal Plain (WBP), comprising >50% of the total land area, many of which are moderate-rich fens. The carbon stocks of moderate-rich fens in the WBP are susceptible to degradation through anthropogenic- and climate-related factors, yet, few studies have aimed to understand their hydrologic function. This study, located in a meltwater channel belt characterized by relatively thin outwash sand and gravel (∼6 m) underlying the peat, provides the first hydrological assessment of a moderate-rich fen in the AOSR. The lithology, hydrological function and groundwater geochemistry all point to the dominance of a local flow system supplying groundwater to the fen areas, evidenced by a thick (∼16 m) and shallow (∼7 m below ground surface) aquitard underlying the outwash, restricting hydrological connectivity between the fen and underlying regional aquifers. Vertical hydraulic gradients between the peat and underlying outwash aquifer, and horizontal hydraulic gradients between the fen and upland varied in response to both short-term and seasonal precipitation trends. Groundwater discharge to the fen was enhanced during wet periods characterized by high rainfall. Conversely, flow reversals (groundwater recharge; fen to underlying aquifer and upland), and subsequently, enhanced fen water table drawdown persisted during extended dry periods. This local groundwater flow-system influences recharge/discharge patterns at Poplar Fen, with hydraulic head in the underlying outwash aquifer highly susceptible to fluctuations in the presence and absence of precipitation-driven recharge from adjacent uplands. Moderate-rich fens similar to that studied here will likely become more susceptible to drying in the future due to a changing climate, leading to enhanced water table drawdown, peat oxidation and subsequent decomposition, vulnerability to wildfire, and seral succession to a more ombrogenous peatland system.

Malaria, Water Management, and Identity in the English Lowlands

AbstractMuch of the eastern seaboard of England lying between East Yorkshire and the Pevensey Levels in Kent constitutes an English Lowlands, a distinctive region characterized by large areas of ma...

Can aerial herbicide application control Grey Willow (Salix cinerea L.) and stimulate native plant recovery in New Zealand wetlands?

SummaryGrey Willow (Salix cinerea L.) poses a significant threat to wetland ecosystems in New Zealand. To manage the ecological impacts and to control further spread, cost‐effective large‐scale control methods are needed. We investigated the response of Grey Willow and dominant wetland plant groups to the aerial boom‐spray application of glyphosate at 9 L/ha and triclopyr (amine) at 18 L/ha at three New Zealand wetlands. We found glyphosate substantially reduced the dominance of tall (>2 m) Grey Willow with commensurate increases in the dominance of most native plant groups. Triclopyr (amine) application resulted in poor Grey Willow control, was not associated with increased native plant group dominance, and some native plant groups declined where triclopyr (amine) was applied. We conclude that the aerial application of glyphosate is an effective large‐scale Grey Willow control tool and could be used to initiate the restoration of native plant communities in wetlands dominated by Grey Willow. But, evidence of Grey Willow recovery after control suggests that increases in native plant dominance will be reversed as Grey Willow re‐establish. Further research is needed to determine how to maintain and enhance native plant dominance after control, and to determine how to manage Grey Willow in fen areas where the Grey Willow canopy is discontinuous and nontarget herbicide impacts can occur. The aerial boom‐spray application of triclopyr (amine) for large‐scale Grey Willow control should be discontinued as it does not provide effective control and results in negative ecological outcomes.

Threshold loss of discontinuous permafrost and landscape evolution.

This study demonstrates linkages between the 1997/1998 El Niño/Southern Oscillation index and a threshold shift to increased permafrost loss within a southern Taiga Plains watershed, Northwest Territories, Canada. Three-dimensional contraction of permafrost plateaus and changes in vegetation structural characteristics are determined from multitemporal airborne Light Detection And Ranging (LiDAR) surveys in 2008, 2011 and 2015. Morphological changes in permafrost cover are compared with optical image analogues from 1970, 1977, 2000 and 2008 and time-series hydro-climate data. Results demonstrate that significant changes in air temperature, precipitation, runoff and a shortening of the snow-covered season by 35days (1998-2014) and 50days (1998 only) occurred after 1997. The albedo reduction associated with 35 and 50days less snow cover leads to increases in shortwave energy receipt during the active thaw period of ~12% (3% annually) and ~16% (5% annually), respectively. From 2000 to 2015, sporadic permafrost loss accelerated from 0.19% (of total basin area) per year between 1970 and 2000 to 0.58% per year from 2000 to 2015, with a projected total loss of permafrost by ~2044. From ~1997 to 2011, we observe a corresponding shift to increased runoff ratio. However, observed increases in the proportion of snow precipitation and the volumetric contribution of permafrost loss to runoff post-1997 (0.6-6.4% per year) cannot fully explain this shift. This suggests increases in drainage efficiency and possible losses from long-term groundwater storage as a result of subtle terrain morphological and soil zone hydraulic conductivity changes. These hydrological changes appear coincident with high vegetation mortality at plateau margins combined with succession-related canopy growth in some bog and fen areas, which are presumed to be drying. Similar changes in runoff response were observed at adjacent Birch, Trout and Jean Marie River watersheds indicating that observations are representative of northern Boreal sporadic permafrost/wetland watersheds in the Taiga Plains.

Climate change effects on lowland stream flood regimes and riparian rich fen vegetation communities in Denmark

ABSTRACTThere is growing awareness that an intensification of the hydrological cycle associated with climate change in many parts of the world will have profound implications for river ecosystem structure and functions. In the present study we link an ensemble of regional climate model projections to a hydrological model with the aim to predict climate driven changes in flooding regimes in lowland riparian areas. Our specific aims were to (1) predict effects of climate change on flood frequencies and magnitudes in riparian areas by using an ensemble of six climate models and (2) combine the obtained predictions with the distribution of rich fen communities to explore whether these are likely to be subjected to increased flooding by a climate change induced increase in river runoff. We found that all regional climate models in the ensemble showed increases in mean annual runoff and that the increase continued through the two scenario periods, i.e. 2035–2065 and 2070–2099. We found concomitant increases in flood levels and flood frequencies. Flood levels and frequencies increased at sites both where the maximum water level was governed directly by river water runoff and where it was governed by river flow roughness (weed cover). We did not find evidence that the present flooding regime was an overall key factor determining the distribution of fen vegetation. However, with the predicted changes in flooding frequencies in the investigated areas we expect to see changes in species compositional patterns within the fen areas under a future climate that may affect the conservation value of these.EDITOR Z.W. Kundzewicz ASSOCIATE EDITOR T. Okruszko

Topsoil removal to minimize internal eutrophication in rewetted peatlands and to protect downstream systems against phosphorus pollution: A case study from NE Germany

This study was conducted in the course of a fen rewetting project in NE Germany aiming to restore a heavily drained spring-percolation mire used as pasture land for more than 100 years. Shallow top soil removal (TSR) up to 40cm was applied to remove the upper degraded peat layer in order to eliminate accumulated nutrients and unwanted seed banks as well as generating material for infilling drain ditches and building dams. This measure has well known positive effects on species development, but very little was known about the phosphorus (P) status in the newly exposed peat soils and porewater. Therefore, we investigated (i) the P mobilisation potential of surface peat soils, (ii) net P release rates in intact soil cores with different degree of peat decomposition, and (iii) P concentrations in porewater of rewetted fen areas with TSR compared to areas without removal and refilled drain ditches. We highlighted that TSR strongly reduced the P mobilisation potential and thereby also the concentration of dissolved P in the porewater at the peat surface. Furthermore, we found low net P release rates close to 0mgPm−2d−1 (median, n=9) in the cut-over areas with less degraded peat similar to those documented for natural fens. Despite of high P concentrations up to 2.6mgL−1 in rewetted areas without TSR (about 50% of total peatland area) there was no evidence of elevated P export to other low-nutrient areas of the fen or in a close-by lake due to high P retention capacity of the iron-rich degraded peat (molar Fe:P ratios >10). It can be concluded that TSR is a suitable measure to recover nutrient poor conditions in rewetted fens in a relatively short timeframe instead of decades to centuries compared to rewetting measures without TSR. This measure is highly recommended if degraded peatlands are characterised by a low P retention capacity or low molar Fe/P ratios in degraded peat (<10) respectively and above all if downstream areas include nutrient-poor systems highly sensitive regarding slightly increased P inputs.

Long-term behavior of groundwater chemistry in a periodically rewetted fen area covered with macrophytes

We studied the long-term changes in groundwater composition in the context of peat restoration at a degraded water-table managed peatland site typical for many agriculturally used fen areas in the northern hemisphere. At the study site, peatland rewetting with groundwater control and pumped canal water was carried out in two periods: from 1997 to 2002 and from 2011 to 2013. The site was not managed between 2002 and 2011, which led to an unstable groundwater table that had declined in part. The aim of this study was to investigate the consequences of rewetting and desiccation on groundwater chemistry. We pursued a multivariate approach using nonlinear principal component analysis (Isomap) to identify the prevailing processes that control the groundwater quality in this system.Sixteen years after peatland restoration, the groundwater quality had significantly improved. Principal component analysis revealed that hydrological processes had a major impact on groundwater quality, i.e. fluctuations between upwelling of local, salt-influenced groundwater and downwelling of surface and rainwater (first principal component) as well as upwelling of regional groundwater from deeper layers (second principal component) which originated from the catchment. In particular, the upwelling of regional deep groundwater had a strong positive impact on the groundwater quality of upper layers at the Biesenbrow site. Another major impact on groundwater quality was nutrient withdrawal by macrophytes and incorporation into organic matter. In the upper groundwater layer, peat mineralization processes resulted in substantially increased SO4 concentrations.We concluded that potential matter release after rewetting is buffered by hydrological barriers, and seems to be marginal with little impact on adjacent environments in the long term. The ecosystem is sustainably stabilized, and therefore has no negative impact on groundwater quality during periods of water shortage. Due to the strong influence of regional groundwater, management measures in the catchment are very important for maintaining and improving groundwater quality in peatlands.

Altered Plant-community Composition and Edaphic Features Associated with Plowing in Southern Wisconsin Fens

The potential for land-use legacies to alter current wetland macrophyte communities and edaphic conditions are underexplored. Here we present results of a study describing associations among these factors in southern Wisconsin fens. Plant-community composition, hydrology, and nutrient availability data were recorded from 1) fens that had been plowed, 2) fens that have never been plowed, and 3) fens with plowed and never-plowed areas. Plowed fens had: 1) lower total species richness, 2) higher invasive species richness, 2) lower native graminoid richness, 3) lower shrub richness, 4) lower root-zone volumetric water content, and 5) higher available N and P then never-plowed fens. Most of these same relationships held when comparing plowed and never-plowed areas of the same fen. Non-metric Multidimensional Scaling revealed that the most important community gradient separates graminoid- and fen-specialist-rich communities from those dominated by invasive species. This gradient also separated plowed from never plowed plots. Accordingly, we believe that a history of plowing has fundamentally altered biotic and, potentially, abiotic conditions, with real consequences for wetland management and restoration.

Carbon, nitrogen, and phosphorus accumulation in novel ecosystems: Shallow lakes in degraded fen areas

Draining fen areas seriously impairs ecosystem services as carbon (C), nitrogen (N), and phosphorus (P) accumulation. Fen restoration has become central in management efforts to recover these ecosystem services in the face of global climate change and water eutrophication challenges. However, restoration has resulted in the creation of shallow lakes, rather than former pristine fen conditions. A new sediment layer, where C, N, and P accumulate, forms at these novel ecosystems, and differs from peat accumulation occurring in natural fens. We performed an initial estimate of C, N, and P accumulation in water inundated fens, and their potential as C, N and P sinks within the temperate area is discussed. Furthermore, the roles of topsoil removal and ecosystem age were considered. A set of abandoned peat extraction sites (n=6), and rewetted fens (n=6) were selected. The effects of topsoil removal prior to restoration are represented by the former sites, which were created 20–86 years ago; and the absence of topsoil removal was represented by the latter, which were established 7–20 years ago. Sediment cores were obtained, and OC, N, and P accumulation rates estimated. Fossil diatoms in the sediment layer–peat interface were evaluated to ascertain trophic conditions in the initial lake formation stages. Surface water quality was analysed to describe current trophic conditions. Our results determined C, N, and P accumulation rates at inundated fens (133.89±7.23gCm−2y−1; 9.60±0.57gNm−2y−1; 0.88±0.08gPm−2y−1) were within the range of natural fens, and other temperate aquatic ecosystems. Topsoil removal prevented eutrophication, and decreased C, N, and P accumulation (P<0.01), although it remains questionable how rewetted sites lacking topsoil removal will function in the long-term. Results demonstrated OM mineralisation has been an ongoing process in the new sediment layer for several decades, what does not occur in water saturated peat at undisturbed pristine fens.

Wetlands in Europe: Perspectives for restoration of a lost paradise

Although 80% of their original area has been lost in the past millennium, Europe's wetlands still cover large areas in the northern part of the continent. Most original wetland types are still represented: bogs and fens are common in the boreal, atlantic and temperate parts of the continent. Riverine wetlands, although strongly reduced in size and functionality, still occur along Europe's streams and rivers. Freshwater tidal wetlands have become very rare in Europe's temperate zone. European wetlands are valued because of their biodiversity and their ecosystem services; their protection and restoration is supported by the Ramsar Convention, EU directives and national legislation for nature protection in the various states. These actions need to be intensified to stop any further degradation of the resource and its many services. The ecosystem services of wetlands should be taken into account in management decisions on land and water use. Multiple wetland restoration initiatives in river catchments and fen areas are good examples of the way forward.

Effects of stream flooding on the distribution and diversity of groundwater‐dependent vegetation in riparian areas

Summary1. Effects of the frequency and duration of flooding on the structural and functional characteristics of riparian vegetation were studied at four sites (n = 80, 50 × 50 cm, plots) along medium‐sized naturally meandering lowland streams. Special focus was on rich fens, which – due to their high species richness – are of high priority in nature conservation.2. Reed beds, rich fens and meadows were all regularly flooded during the 20‐year study period, with a higher frequency in reed bed areas than in rich fen and meadow areas. In rich fens, species richness was higher in low frequency flooded areas (≤3 year−1) than in areas with a high frequency of flooding (&gt;3 year−1) or no flooding, whereas species richness in reed beds and meadows was unaffected by flood frequency.3. The percentage of stress‐tolerant species was higher in low intensity flooded rich fen areas than in high intensity and non‐flooded areas, indicating that the higher species richness in low frequency flooded rich fens was caused by competitive release. We found no indication that increased productivity was associated with high flooding frequencies.4. We conclude that the restoration of morphological features in stream channels to increase the flooding regime can be beneficial for protected vegetation within riparian areas, but also that groundwater discharge thresholds and critical levels for protected vegetation should be identified and considered when introducing stream ecosystem restoration plans.