Approaches in WetlAnd REstoration

- focus on fen landscapes

Materials from international workshop, 21-23 April 2013, Warsaw

Scope of workshop

Key-note abstracts


Case studies

The workshop was financed by the Polish Ministry of Science and Higher Education (grant no. N N305 148739).



Citing items published on this web page

We recommend the following format of citations:

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Plant diversity

Bird diversity

Biodiversity - other aspects

Sustainable use

Flood protection & water resources

Synergies & trade offs


The hemiparasite Pedicularis palustris favours the restoration of undrained fen-meadow vegetations  
Research Institute for Nature and Forest, Kliniekstraat 25, 1070 Brussel, Belgium

In our study we show that Pedicularis palustris, an endangered hemiparasite in large parts of Europe, can act as an 'ecosystem engineer', speeding up the restoration of undrainedf en-meadow ecosystems colonized by species-poor and resistant Carex acuta vegetation. The parasitic behavior of Pedicularis palustris on tall sedges significantly alters local plant diversity, biomass production and soil characteristics. Our experiments show that, under the right hydrological conditions and mowing management practice, several target species for nature conservation can benefit from the gaps it creates in above-ground Carex acuta vegetation and its dense below-ground root system. The more prominent presence of mosses and lower density of the topsoil stimulates the recovery of mesotrophic transition mire with active peat formation, a habitat type specifically protected under the European Habitat Directive.  

Shrub removal – an effective measure to restore biodiversity of fen meadows?  
1) Wetland Conservation Centre, Andersena 1B/19, 01-911 Warsaw, Poland; 
2) Institute for Life Sciences & Technology, Falenty, Al. Hrabska 3, 05-090 Raszyn, Poland; 
3) Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland 

We investigated the effects of willow scrub removal combined with blocking water outflow and re-introduction of mowing, in a wet meadow on a drained soligenous fen. We analyzed the response of 4 functional groups of plants (target and non-target species) and the effectiveness of suppressing shrub re-growth with 4 different treatments. Six years after restoration measures, there is a significant increase of abundance of fen and wet meadow indicators on shrub removal plots. From the analyzed methods for suppressing willow re-sprouts, the most effective is applying herbicide on re-sprouts’ leaves in the first season, followed by annual mowing. The suppressing effect is comparable to intensive mowing of re-sprouting shoots. We conclude that shrub removal facilitates recovery of fen species in rewetted fen but this effect can only be maintained if shrub re-sprouting is actively suppressed.  Article in "Journal for Nature Conservation"

The functional limits of donor meadows in fen restoration through top soil removal and hay transfer 
Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland 

A method used to restore degraded fens is removal of degraded top soil followed by species introduction from reference-sites via hay transfer. In 2009 we initiated a full-factorial fen restoration of top soil removal followed by species introduction from reference sites. Variation in top-soil removal depth caused differences in elevation above the ground water level. After three years both top-soil removal treatments resemble the reference-site more than the control site. A functional analysis shows that the hay differs in functional characteristics from the reference sites by having traits characteristic of more ruderal species. Elevation showed a negative correlation to Ellenberg-F value, clonal lateral spread, hydrochory and a positive correlation to SLA, autochory, Functional Richness and Functional Dispersion. Our results show that complimentary seed input is necessary in addition to the hay, and that a variation of depth is required to ensure a diversity of selection pressures.  

Calcareous spring fens in South Estonia 
Institute of Ecology, Tallinn University, Uus-Sadama 5, Tallinn 10120, Estonia

Our aim was to ascertain the state of calcareous spring fens, their vegetation, hydrology and landscape setting in South-Estonia on the Haanja and Otepää Heights and Sakala Upland. We analysed plant cover, sampled surface water for pH and specific conductivity (EC) on 63 sites including 17 actively tufa precipitating fens. The surface water pH ranged from 6.6 to 8.1 and EC was from 225 to 905 µS cm–1 on the sites studied. On plots (2x2 m2) we registered 86 vascular plant species, which clustered into four assemblages: Molinia caerulea + Carex lasiocarpa + C. davalliana, Schoenus ferrugineus + Carex lasiocarpa, Cirsium oleraceum + Menyanthes trifoliata + Phragmites australis and Carex rostrata. Likely the precipitation of tufa does not affect species richness, Only the Carex rostrata assemblage was in every site related with tufa formation although the depth of the water table was below the surface for the assemblage.  

Vegetation dynamics on sediment deposition sites on the River Emajogi floodplain, Alam-Pedja NR, Estonia 
Institute of Ecology and Earth Sciences, Estonia University of Tartu, Lai 40, Tartu 51005, Estonia

In 2011, the LIFE+ project HAPPYFISH re-connected ten river meanders (oxbows) to the River Emajogi in Alam-Pedja NR, Estonia.During re-opening of the oxbows, sediments were excavated and deposited on adjacent flooded meadows, in a layer of ca 0.5 m and an area ca 50*100 m per site. We monitored the vegetation before (0-yr) and after (1-yr, 2-yr) sediment deposition. The 0-yr vegetation was species poor and dominated by tall Cyperaceae and Poaceae. By 1-yr, the average richness increased from 6 to 23 species per plot, and the proportion of species not characteristic to floodplains increased from 0.01 to 0.3. We expected the 1-yr species assemblage to be rather random, as the established species have not yet experienced local environmental filtering (flood) nor competition. Indeed, the 2-yr vegetation already lost some species, and the main cause for that seems to be the competition by fast-growing flooded meadow plants and not so much the environmental filtering per se.

A trial of restoration of Molinion meadows to enhanced plant diversity; case study Kampinos National Park 
Department of Geobotany and Plant Ecology, University of Łódź, Pilarskiego 14/16, 90-237 Łódź, Poland 

Molinion meadows are disappearing plant communities in all of Europe. Active protection measures are taken to save this community. In Kampinos NP one of the most diverse fen meadows complex were investigated since 1993. A majority of meadows were mown regularly to the beginning of 90. In the late 90. because of paludification only a small fragment was mown but height water level inhibited the succession. Since 2000 year meadows complex has been included into the plan of active protection but stagnant water prevents mowing the most valuable parts. The majority of special care species connected with purple grass meadows was preserved but the decrease of meadows and increase of willows thickets were observed. In 2009 the willows (Salix rosmarinifolia) were removing from patches where Molinion meadows existed. A comparative analysis conducted three years later shows that the restoration of diverse meadows is still possible. meadows.

Biodiversity of traditionally used boreal hay lands: changes, dynamics and threats 
Norwegian University of Science and Technology in Trondheim, Museum of Natural History and Archaeology, Section of Natural History, NO-7491, Norway

For more than four decades succession in boreal plant communities and population dynamics of outlying hay fens have been studied in permanent plots in two nature reserves in central Norway. The main aim is to document the effects of management activities such as mowing, trampling, burning and cattle grazing. The long-term data also allows us to quantify effects of climate change. The pleurocarpous, prostrate bryophytes (e.g. Campylium stellatum) are favoured by mowing, whereas acrocarpous and ‘hummock-building’ bryophytes are reduced. Mowing leads to a general reduction in woody plants and herbs, whereas the proportion of graminoids is increased. The reduction of aboveground biomass with increased frequency of mowing is not due to an impoverishment of the soil, but due to the high degree of disturbance caused by regular mowing. Cost of reproduction, summer temperature and precipitation are important factors affecting the population dynamics of fen and grassland species. Management activities interact with the factors, and climate change will alter the effects of management on population growth rate and population viability. Four doctor theses and a large number of papers have been published from the long-term studies; see:

Restoration of raised bog habitats in Melnais Lake Mire in Latvia 
University of Latvia, Kandavas Street 2, Riga, LV-1083, Latvia

From 2010 - 2013 the EC LIFE+ Project „Restoration of Raised bog habitats in the specially protected nature areas of Latvia” is carried out in 4 sites – Melnais Lake Mire, Aklais Mire, Rozu Mire and Aizkraukle Mire and forests”. Negative threats to the sites include drainage and peat extraction close to. In 2010, habitat and hydrological monitoring was started Melnais Lake Mire. The aim of the study is to evaluate the effectiveness of raising water level and the concomitant increase of the coverage of raised bog species. In total, 58 habitat monitoring plots and 13 groundwater monitoring wells were set up in degraded and intact area. 
In January 2012 the raised bog habitat restoration by building dams on the drainage ditches was started in Melnais Lake Mire. Six month after building of the dams in Melnais Lake Mire positive changes were observed in the mire vegetation as the coverage of Eriophorum vaginatum, Rhynchospora alba, Sphagnum angustifolium, S. cuspidatum increased.

Effect of N and P on the growth of mosses on calcareous fen
Institute of Ecology, Tallinn University, Uus-Sadama 5, Tallinn 10120, Estonia

Restoration of moss carpet is crucial task because bryophytes are considered ecologically important constituents in plant cover of Ca-rich fens. We set up fertilization experiment on weakly drained fen in N-Estonia and hypothesize that two key moss species differ in their response to added nitrogen and phosphorus. Average water level was 2-3 cm below the surface on experimental site. N treatment had no effect on N content in Campylium. The production of Campylium was closely related to P in the moss but was suppressed by CaCO3 that covered moss stems. The positive effect of P on the production of Scorpidium was much less evident, but its production was suppressed by the supply of N. We concluded that two species differ in their response to N and P: Campylium production is limited by P shortage whereas the production of Scorpidium is less P-limited but more depressed by redundant N easily trapped from surrounding fen water.  

Shrubs expansion after deep-seated fire on the Biele Suchowolskie fen 
Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland 

In 2002 a deep-seated fire occurred on the drained fen “Biele Suchowolskie”, located in the Biebrza National Park. In 2004 a 1-hectar, permanent research plot was established, comprising patches of unburnt, surface-burnt and deeply-burnt areas. Every four years 10 releves were taken to describe secondary succession patterns. On the burnt patches development of woody plants was observed, leading to disappearance of herbaceous species. In 2004 shrubs covered 8,75% of the studied area, and increased to 75% in 2008 and 87,8% in 2012. By 2012 all the burnt patches have been covered with Salix cinerea shrubs forming Salicetum pentandro-cinereae association, irrespectively of fire intensity. Unburnt patches remain covered with herbaceus plants, which gradually shifted to meadow vegetation.Probably the fire increased nutrient bioavailability in peat thus allowed shrubs growth. Actions such us mowing and hay removal seem to be essential to stop the shrub invasion after fire. 

Re-establishment of native plant species in a drainage-influenced spring fen
Institute of Ecology, Tallinn University, Uus-Sadama 5, Tallinn 10120, Estonia

Effects of cutting Molinia tussocks and raising the water level on the recovery of native plant cover on a Ca-rich fen were studied on spring fen Paraspollu (N-Estonia). Five experimental blocks by 10x10 m, 21 plots by 1x1 m on each were established. In every block tussocks cut down at different height, water level kept in different depth, species composition monitored on plots during 3 years. As a result, Carex davalliana and Schoenus ferrugineus germinated well on plots where Molinia tussocks were cut down on zero or half of height, but moss cover re-established in plots with above-surface water level only. In conclusion, deep cutting of Molinia tussocks and temporary inundation with Ca-rich spring water likely supports the re-establishment of native plant species on Ca-rich spring fen.


The Greater Spotted Eagle - how we can improve its habitats? 
Biebrza National Park, Osowiec-Twierdza 8, 19-110 Goniądz, Poland 

The Greater Spotted Eagle is one of the most endangered species of birds of prey in the world. Therefore it is the highest need to protect that species actively. One of the most important threats is drainage of its habitats. There are several methods of active protection which may improve ecological conditions of habitats, in particular wetlands. We expect some measurable results of the use of these methods.  

Restoring and conserving habitats of Aquatic warbler (Acrocephalus paludicola) in the Biebrza valley 
Polish Society for the Protection of Birds, Odrowąża 24, 05-270 Marki, Poland; Biebrza National Park, Osowiec-Twierdza 8, 19-110 Goniądz, Poland 

Fen peatlands of the Biebrza Valley (NE Poland) host 2,500 singing males of Aquatic Warblers, equaling c. 20% of the world population of this globally threatened bird species. After traditional hand-scything ceased in 1970s, successional overgrowth has become the main threat to this habitat, with over 15,000 ha affected by 1999. Since 2005 the Polish Society for the Protection of Birds (OTOP - BirdLife Poland) with Biebrza National Park and other partners have been implementing LIFE Programme projects targeting the conservation of Aquatic Warblers and their fen mire habitats. Projects activities have shown that landscape-scale habitat management at Biebrza valley is possible. The development and introduction of prototype machinery on caterpillars (ratrak) allow large scale mowing. Thanks to ratrak machines, funds of LIFE projects and agri-environmental schemes, almost 7,000 ha of State owned land was managed during last 6 years preceded by restoration of open landscape by shrub and tree removal. The low quality biomass is processed in a pelleting facility. Monitoring of results shows that this management has been beneficial for Aquatic warbler and other bird species but some damages of vegetation were observed. To avoid the latter the frequency of mowing was reduced to once every four years. Also possibilities of improving machines and techniques of mowing and biomass collection are being explored.  


Active management vs. threats of mires in Biebrza National Park 
Biebrza National Park, Osowiec-Twierdza 8, 19-110 Goniądz, Poland 

The Biebrza National Park was established to protect the largest area of wetland ecosystems in CEE. The Biebrza is well known for its biodiversity. The park administration is responsible to maintain those high natural values. Secondary succession (wood encroachment) is considered as the main threat of the mires. Active management carried out by park officers focuses on mowing and shrubs removal. The question that will be explored in this poster is whether this is sufficient to protect mires? 

Kampinos National Park solutions to wetland conservation 
Kampinoski National Park, Tetmajera 38, 05-080 Izabelin, Poland 

200 years ago approx. 80% of the area of marshland belts in Kampinos National Park (KNP) was covered by wetlands and temporarily flooded areas mostly overgrown by alder forests and sedges and reeds. Nowadays, due to meliorations, embankment of the Vistula river and deforestation, wetlands cover only 30% of the area of marshland belts, while alder forest grow on less than 15% of this area. The remaining fragments are mostly covered by used and abandoned meadows and natural and artificial forestations. KNP implements a number of activities, related to restore and protect the biological diversity of wetlands, including the most valuable fragments of semi-natural ecosystems, which appeared in the course of many years of traditional farming, for example: the buying of land from private owners, small retention and the mowing of meadows. In 2008-2011 a project for the development of scientific, complete methodology for the selection of activities aimed at restoration of hydrological conditions has been prepared and now we are trying to get funding for a project related to the implementation of its recommendations.  

Integrated studies on ecological effects of river restoration: a row of oxbow lakes reconnected with the river channel, an example of the Słupia river 
Institute of Biology and Environmental Protection, Ecology Department, Pomeranian University in Słupsk, Arciszewskiego 22, 76-200 Słupsk, Poland 

Ecological restoration has become a highly appropriate management objective in the Słupia river floodplain (N Poland). To mitigate the ecological effects of the channel straightening, a pilot restoration project based on the reconnection of 3 oxbow lakes has been launched in 2007. The oxbow lakes were reconnected at both sides to the main river channel in order to obtain a system open to flow. Simultaneously, the ecohydrological monitoring of restored oxbows was established. Besides a measurements of flow rates and changes in cross-section areas, macrozoobenthos was chosen as a representative group of organisms indicative of long-term effects of restoration efforts. In the period 2007-2012 we found decrease in both abundance (1.1-times) and biomass (2.2-times) of benthic fauna as the effect of oxbow lakes reconnection. 

Protecting alkaline fens (7230) in the northern Polish postglacial landscape 
Naturalists’ Club, Świebodzin, 1 maja 22, 66-200 Poland 

The strategic objective of the project is to stop degradation and to improve and maintain the favourable conservation status of alkaline fens in 29 Natura 2000 sites.The operational objectives of the project are:
- Inhibition of excessive runoff and increase groundwater levels in the alkaline fens,
- Halting biodiversity decline due to the expansion of peat species characteristic of habitats with a lower moisture content such as grasses, trees and shrubs,
- Strengthening the regional population of extremely endangered species of Saxifraga hirculus,
- Dissemination of conservation methods based on good conservation plans and management plans based on solid, scientific basis including hydroecological aspects,
- Promote the protection of alkaline fens as refuges for rare and endangered species also forming regional and local natural attractions,
- Promote the protection of alkaline fens as CO2 accumulating areas and supporting measures to reduce the effects of global warming. 

Life+ Nature-Project „Preservation and restoration of base-rich to alkaline fens in Brandenburg“ 
Naturschutzfonds Brandenburg, Germany Heinrich-Mann-Allee 18/19, Potsdam 14473, Germany

In January 2010, the LIFE Nature Project „Alkaline Fens in Brandenburg“ was established. Through this project, the “Naturschutzfonds Brandenburg” manages conservation activities intended to secure and develop alkaline fens in 14 Natura-2000 areas until the beginning of 2015. During the project 150 ha of reed have been mowed in 10 project areas. Additionally shrubs were removed on 33 ha in 11 project areas and 35 ha of pasture for water buffalo and sheep were fenced in. The next step is to restore the natural water balance within the areas. To achieve this, the drainage systems have to be deactivated. On moderately to strongly sloped fens it is necessary to fill up the drainage ditches completely. The filling material is obtained by top-soil-removal directly on bordering moorland. So far 19 km of drainage systems have been deactivated and top soil removal has taken place on an area of 10 ha in 6 project areas. The results of the rewetting efforts can be seen almost instantly after the drainage systems are dea tivated. Species like Equisetum palustre, Juncus articulates, Menyanthes trifoliata and brown mosses have started to grow on bare soil locations within one vegetation period. The results of the conservation measurements so far give hope that initial moor-revitalization has succeeded. To what extent damages caused by drainage are reversible will become evident during the next years and decades. 



Favored Areas (FA) for integrated land use in Europe 

1)Lower Saxony Water Management, Coastal Defense and Nature Conservation Agency, An der Scharlake 39, 31135 Hildesheim, Germany; 
2) Alterra (Wageningen –UR), Koppenberch 18, Doesburg 6982 CZ, The Netherlands; 
3) Radboud University Nijmegen, 6500 HC Nijmegen, The Netherlands 

Half of Europe`s land surface are so called Less Favored Areas (LFA`s) reflecting low productive agricultural sites. These areas include bogs, fens, floodplains, moorland and heathlands. The poster provides an overview of the interaction between economy and ecology of semi-natural habitats, restoration efforts and examples of integrated land management of heathlands and peat fen meadows in Europe. The outcome of these projects supported by scientists, farmers and nature managers across Europe operating in the Rural European Platform and the Dutch community of practice of shepherds "that is why we eat mutton" is that in many places in Europe LFA`s are becoming Favored Areas (FA`s) for integrated land use systems. In particular where there is a scarcity of nature, i.e. in the densely populated regions in Europe. Examples from Germany and The Netherlands will be provided. 

Restoration of a Mediterranean drained peatland: the case study of the Massaciuccoli Lake Basin (Tuscany, Italy) 
Institute Of Life Sciences -Scuola Superiore Sant'anna-Pisa, via S.Cecilia 3, 56127, Italy

The Massaciuccoli lake basin (Tuscany, Italy), characterized by a Mediterranean climate, is a typical artificially drained coastal floodplain impacted by excess nutrient loading primarily from agricultural activities. Due to the complex hydrological setting of the area and to the high soil organic matter content (up to 50%) problems such as phosphorus leaching and subsidence are exasperated. A project started in 2012 has identified a solution to restore the lost ecological functions in rewetting part of the area. In our pilot experimental field of 15 ha, three different management systems with an increasing anthropogenic impact will be tested: natural wetland, constructed wetland and vegetation filters. Surface water quality, peat oxidation rate, methane-cycling microbial communities activity, CH4 and CO2 soil emissions, plant nutrient removal, biomass production and energy efficiency will be monitored in order to assess the most effective and sustainable management system.

Preferential flow in water repellent peat-moorsh soil as a constraint in rewetting drained fens 
Faculty of Civil and Environmental Engineering, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland

The main objective of this study is to investigate the influence of water repellency on the observed field Wykowo, located within Kuwasy drainage-subirrigation system. Research took place in the peat-moorsh soil profile located at the Biebrza River Valley. The variability of soil moisture and dry bulk density were studied in transects by intensive sampling. The persistence and degree of water repellency was examined in the soil using water drop penetration time (WDPT) and alcohol percentage tests. The highest repellency was reported in the alder peat. The influence of soil moisture content on water drop penetration time was analysed. The research showed a dependence of water repellency on soil water content. The observed soil moisture patterns in the field were very variable and showed the existence of the dry soil areas, located just above the layer with the highest water repellency. The existence of the water repellent layer can have negative influence on capillary rise, infiltration and retention and therefore acts as a constraint in the restoration of drained peatlands by rewetting.   


How much for water on wetlands? Economic quantification of the storage role of the Biebrza Valley 
Faculty of Civil and Environmental Engineering, Department of Hydraulic Engineering, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland

The role of wetlands in water storage becomes one of the hottest topics in contemporary worldwide discussions on possible benefits that come along with an appropriate status and function of those ecosystems. On the basis of temporal and quantitative analysis of flood volume dynamics and the economic analysis of unit cost of water storage in the catchment of Biebrza the monetary value of water storage in the Lower Biebrza Basin was estimated to amount approximately 0.36 EUR/m3/year. The average monetary gain that results from the floodplain storage volume and water retention during floods (regarding flood extent and duration) reached the average value of 3.54 mln EUR per annum in the years 1995-2011, which can be considered as a quantified ecosystem service of the Lower Biebrza Basin. Results of the research can contribute stakeholder communication in order to present other-than-environmental approaches to wetland management.  

Poland will be soon a perfect site for river restoration 
1) Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland; 
2) WWF Poland, Wiśniowa 38, 02-520 Warsaw, Poland 

… because most of the rivers will be destroyed. Such a scenario is regrettably not a black joke. In Poland the ghosts of the past of river training and drainage returned unexpectedly after the 2010 flood. Provincial authorities responsible for management of secondary water courses on a large-scale initiated deepening and sediment removal from rivers, realised under rationale of „removing flood damages”, „conservation” or „maintenance works”, but in fact resembling the regulatory works. These works have been in many cases carried out on areas without any flood risk, regardless of area nature conservation status and without EIA studies. Based on documents assembled from 10 provinces, we estimate that above 5.500 km of courses have been treated with “sediment removal” in 2010-2012, including several hundreds within Naura 2000 sites. The problem was reported to the European Commision, which already proceeds several cases against Poland, due to violation of water management laws. Despite that, regulatory works are still being carried out. 

Resolution on Polish Rivers adopted on 23 April 2013 by participants of the international workshop “AWARE: Approaches to Wetland Restoration


Measurements of methane emission from a temperate peatland by eddy covariance method 
Department of Meteorology, Poznan University of Life Sciences, Piątkowska 94, 60-649 Poznań, Poland 

Measurements are conducted in Rzecin peatland, which is located in one of the biggest Polish forest complex namely Nadnotecka Primeval Forest. Methane is one of the most important greenhouse gases and wetlands are one of the major source of this gas into the atmosphere. The emission of CH4 is strongly related to the anaerobic conditions, which are the result of the high water table in this type of environment. In this study the net gas exchange between wetlands and atmosphere is measured with eddy covariance method. The system consists of: sonic anemometer and a closed-path gas analyzer. CO2 concentration is measured with open path gas analyzer. Data were divided to four wind direction sectors selected after initial analysis of methane effluxes against wind direction and by dominant vegetation in different sectors. The highest methane efflux was observed from the sedge covered area while the presence of reed and cattail plants caused the lowest emission from northern part of studied.

Restoration of ecosystem services of fens with topsoil removal 
Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland 

In our research we compared topsoil removal with experimental rewetting in terms of methane emission, nutrient release, primary productivity and its limitation in a large percolation mire drained for agricultural purposes. In 2008, decomposed topsoil was removed over 2 ha down to the mean summer groundwater level. Along with those activities experimental rewetted plots were prepared by drowning sods with degraded substrate in the groundwater. We monitored geochemical properties, primary productivity and its limitation as well as methane emission within degraded (control), topsoil-stripped, rewetted and reference communities. Results show significant influence of topsoil removal on limitation patterns and nutrient content when compared with control and rewetted plots. Moreover, contrary to rewetting, topsoil removal did not increase CH4 emissions. We conclude that topsoil removal can successfully restore multiple ecosystem services of fens and point to the need of finding sustainable economic use of the removed topsoil, which could lower the costs of this restoration method.  


Assessing eutrophication risk imposed by fen rewetting in the Biebrza “Triangle” area (NE Poland) 
1) Faculty of Civil and Environmental Engineering, Department of Hydraulic Engineering, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland; 
2) Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland  

Restoring drained fens by rewetting bears a taint of eutrophication caused by P mobilization from degraded peat, which may increase productivity in P-limited terrestrial and aquatic systems. We assessed this risks for the Middle Basin of the Biebrza Valley, NE Poland, where a several km2-large part of a fen system drained in the 19th century is being rewetted by damming drainage channels. We modeled the spatial extent and the degree of predicted P-eutrophication using a quasi-3d groundwater flow model, LIDAR-based digital elevation model and soil stratification data (depth and degree of peat decomposition). The produced map of predicted increases in productivity and moisture was overlaid with a vegetation map to identify patches of Molinion meadows under threat and predict their reaction to rewetting after verifying their P-limitation. Further, we analysed transport pathways of the total soluble P from rewetted fens towards rivers using 1-d hydrodynamic model. We identify the most vulnerable patches of fen meadows and river sections and conclude that such conflicts are largely unavoidable and require strategic decisions for each individual area.  

Combating succession in fens using large tracked mowing machinery may reduce plant diversity: an early warning from the Biebrza National Park (Poland)  
Department of Plant Ecology and Environmental Conservation, Institute of Botany, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland 

In Biebrza National Park (BNP), EU largest fen conservation area, dereliction has affected more than 300 km2. To combat unwanted succession and restore open seminatural landscape, tracked mowers were developed in 2007 based on snow grooming vehicles and increasingly applied in BNP (now on c. 7 km2) as well as in other European fens. While effects on birds seemed promising, the impact on plants remained yet unknown. We present the first assessments of the response of plant communities to this management by comparing 12 pairs of mown and unmown plots spread over several km2. Data were analyzed using functional trait diversity approach. Tracked vehicles suppressed hummock mosses, tussock sedges and shrubs and facilitated semi-aquatic clonal forbs and hollow mosses. We also recorded higher mean specific leaf area in mown plots. Analysis of functional diversity indices showed a decrease of Functional Divergence due to mowing, which suggests that species with extreme trait values are most suppressed. We associate these changes with the reduction of micro-topography by caterpillar tracks and argue for a more care when applying tracked machinery in fen conservation.  Artcile in "Biological Conservation"

A dormant fen: the underestimated value of dead organic matter metabolism in wetland functioning and restoration 
The Nature Laboratory, ul. Sosnowa 8, 95-050 Konstantynów Łódzki, Poland 

The dormancy period in wetlands is usually considered unimportant in their metabolic balance and system biogeochemistry, hence only few research data exist and only data from the vegetation period are used for restoration planning. In early spring flows of water between upland areas, floodplain wetlands and rivers or lakes often are at their peak intensities. The quality of water from wetlands then affects algal blooms and macrophytes in water bodies, and indirectly other functions of the whole aquatic ecosystem.Examples are given how local hydrologic constrains and plant species as a source of dead organic matter influence processes of oxygen consumption and nutrient uptake or release. Results are important for decisions concerning the water level and its dynamics, whether to leave or remove plant organic matter, which species should be promoted for particular ecosystem functions, and how relevant biogeochemical constrains are important for particular species as conservation targets.