Prospects of fen restoration in relation to changing land use—An example from central Poland

We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using historical maps. Major hydrological changes occurred after c. 1950 when a dense drainage network was constructed and in the last decade when large fishponds were built. Nowadays, water levels in most of the fens and fen meadows are too low and the fluctuations too large for a long-term preservation of fen ecosystems. The mean water tables range from 0.3 to 0.8 m below soil surface with fluctuations from 0.7 up to 1.5 m. A second important cause of the hydrological changes of the system was the afforestation of the adjacent infiltration areas leading to increased evapotranspiration and a decreased groundwater flow to the wetlands. Finally, a recent increase in groundwater abstraction for agricultural purposes has probably lowered the groundwater even further. We conclude that a full restoration of the fen is not possible under the present conditions. An alternative restoration goal could be conservation and restoration of species-rich fen meadows, but also then improving the hydrological conditions will be necessary. While the focus is often on the local factors influencing the restoration prospects of a fen system, the regional processes are at least equally important. In this paper we discuss an importance of both local and regional factors