Restoration of the hydrological regime in Tartokas fen

Tartoko fen (38 ha) is located in Southern Lithuania, in the north-eastern part of Prienai, in the territory of the Nemunas Loops Regional Park. It is unique that this fen has survived to the present day within the city limits, is characterized by valuable biodiversity. The habitats of the European Importance 7230 Alkaline marshes and 6450 Alluvial meadows are home of rare species important in national, European and global levels. Since 2009, Tartokas fen (code LTPRI0004) is part of the European ecological network Natura 2000, which is important for the conservation of rare species and natural habitats. In 2010, Tartokas fen was granted the status of a telmological (mire) reserve. Rare and protected species are found in the reserve: fen orchid (Liparis loeselii; protected under the Washington and Bern Conventions, the European Community Habitats Directive (Annex II), in our country it is a nationally protected species of the family Ochidaceae), brown bog-rush (Schoenus ferrugineus), common redshank (Tringa totanus). In 2002, felwort (Swertia perennis) have not yet been found in the area, but have not been detected in subsequent surveys, but it is likely that the population may be restored following successful management measures.

 

Extensive mowing and grazing have long ensured the good condition of protected species and habitats. With the cessation of farming, the area was gradually overgrown with shrubs and reeds, threatening the survival of open wetland and wetland habitats and protected species. The condition of the wetland is also negatively affected by the drainage system installed in the Soviet era, which is flooded by beavers in some sections. In recent years, the nature management measures applied in the reserve - shrub felling and irregular reed mowing, as well as the occasional activity of beavers - have helped to improve the condition of protected species and habitats, but not enough. Additional measures are needed to ensure the good condition of the ecosystem and the protection of protected natural values, such as the restoration of groundwater levels, regular extensive mowing and grazing, the cutting of cuttings and the removal of cut biomass from the site. Restoration of the hydrological regime of the wetland will also contribute to the reduction of greenhouse gas (GHG) emissions from the drained areas of the wetland and the resumption of the peatland process.

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Environmental issues

The state of the Tartokas fen habitats is related to the hydrological regime of the fen. Drainage-affected marshes and alluvial meadows require maintenance and extensive farming. The system of drainage ditches still operating in the wetland disturbs the hydrological regime of the wetland: the waters of spring frost and precipitation are not retained in the wetland, because the drainage ditches flow out of the territory rapidly. In the drained peatland, the decomposition of the peat layer is activated, accompanied by GHG emissions. Eventually, woody vegetation begins to form in the unmoved and non-mowed fen, and reeds in slightly wetter areas. Due to the vulnerability and instability of the Tartokas fen habitats, the fate of the perennial floodplain population, which was last inventoried in 2002, is also threatened. Habitats are threatened with extinction as habitats continue to dry out and grow on woody vegetation or reeds. The two-leaf mire conservation plan (2017) states that as habitats deteriorate, these plants become less viable, bloom less, produce few fruits, and individual mortality in such populations is very high (in some cases, individual mortality may reach 52% per year, and up to 97% over a 5-year period).

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The aim of the project is to create conditions for the restoration of the hydrological regime of the Tartokas fen, thus reducing GHG emissions, and to maintain the favorable condition of the restored natural habitats and protected species.

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Project objectives:

●     to prepare and coordinate planning documents (Management Plan, hydrological regime restoration project) and other documentation that may be required during the project implementation;

●     to carry out monitoring of the groundwater level (GVL) and assessment of GHG emissions (based on the GEST methodology) before and after the implementation of nature management works;

●     to implement the restoration works of the hydrological regime;

●     to cut down woody vegetation and excess reeds, to remove biomass from the territory; 

●     in co-operation with the Nemunas Loops Regional Park Directorate (a subdivision of the State Service for Protected Areas), the local community and local farmers to ensure further maintenance of the area (grazing and mowing in an area of at least 20 ha).

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Expected results:

●     prepared and agreed spatial planning documents;

●     restoration works of the hydrological regime have been implemented and conditions have been created for the recovery of the wetland;

●     favorable conservation status of habitats and protected species of EC importance is ensured;

●     reduced GHG emissions in an area of about 20 ha about 50-60 t CO2 eq. per year. The GHG emission reduction calculator is provided in Annex 1.  

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Work is currently being carried out in the Tartokas fen: removal of atypical vegetation, planning activities, hydrological monitoring.