A dozen or so years of observations of alkaline fens in northern Poland indicate different dynamics of vegetation changes. Among tens of alkaline fens, the following can be considered as the best preserved and representative vegetation maintaining its unaltered character (in the absence of protection measures or their occasional use) over the last dozen or so years: Bagno Stawek Reserve, Mechowisko Radość, Mechowisko Manowo, Rospuda Valley, Torfowisko Morgi, Torfowisko Zocie, and Kobyla Biel.
The process of slow changes of vegetation within these fens should be linked to the preservation of natural or only slightly modified hydrological conditions within their surface and underground catchment areas. The different dynamics of changes in the vegetation of alkaline fens apply not only in relation to entire sites but also within fragments of fen complexes. Examples include the fens of the Ilanka and Pliszka River Valleys.
Protective measures consisting in the regulation of groundwater level, removal of forest and rush vegetation, as well as mowing may result in various effects and protective measures, limited only to raising the water level within alkaline fens with altered hydrological conditions, contribute little to inhibiting the expansion of forest vegetation. Raising the water level in sites where the top layer of peat is mineralized contributes to the expansion of rush vegetation.
Maintaining or restoring vegetation characteristic for alkaline fens in strongly transformed sites is possible by raising the water level combined with simultaneous intensive removal of biomass, but sometimes for unknown reasons the implementation of this measure – even for many years – does not bring the desired effects. Occasional (every 3 – 5 years) removal of tree wildings ensures that the characteristic vegetation of the least transformed alkaline fens is maintained. The use of moss fens with heavy mechanical equipment, such as groomers, has a negative impact on the ecosystem by homogenizing the structure of the fen and affecting its biodiversity. In the case of removal of bushes from alkaline fens, it is necessary to remove the root offshoots for several consecutive years.
Alkaline fens are distinguished by many specific features, depending on the local hydro-ecological conditions, and require highly individualized treatment in the selection of protection methods.Thanks to the project, we managed to:
Already in September 2018, together with entities from Belgium, we started the implementation of another LIFE project – Green Valleys – which continues the idea of protecting the habitat 7230, although it focuses primarily on solving the problem of biomass accumulation (coming from the mowing). More on the LIFE Green Valleys project website (a Polish version of this page will be created soon).
The project entitled: “Conservation and restoration of alkaline fens (code 7230) in the young-glacial landscape of the northern Poland” was financed from LIFE+ funds and the National Fund for Environmental Protection and Water Management, managed by the Naturalists’ Club in partnership with the Regional Directorates for Environmental Protection in Gdańsk and Olsztyn. The project was executed from 09/2012 to 06/2018 and assumed slowing down the process of degradation as well as improvement or maintenance of the condition of alkaline fens in the northern Poland, in 30 Natura 2000 sites, as the habitats of many rare, protected and almost extinct species of plants, including in particular the species from Appendix II of the Habitats Directive (Saxifraga hirculus, Liparis Loeseli and Hamatocaulis vernicosus). Among the selected areas, 89 of the most precious and best preserved Polish alkaline fens were listed, within the area, among others, Rurzyca Valley, Augustów Primeval Forest, Kaszubskie Lake District, covering the area of the following voivodeships: lubuskie, wielkopolskie, zachodniopomorskie, pomorskie, warmińsko-mazurskie and podlaskie.In particular, the project will aim to:
With such a construction, the Project created an opportunity to maintain a favourable conservation status or improve the condition of the most valuable areas of habitat 7230, constituting app. 70% of surface resources of the northern Poland (30% of the national resources) of this habitat with the current, characteristic sedge and moss plants. Additionally, execution of the project will contribute to enhancement and maintenance of app. 90% of position of Saxifraga hirculus, app. 50% of the national positions of Liparis loeselii and Hamatocaulis vernicosus as well as approximately 50% of the positions of other very rare species, e.g. Stellaria crassifolia, or moss Messia triquetra, Pseudocaliergon triforium and Cinclidium stygium.
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