Measures to develop a rich-fen wetland landscape with a full range of successional stages

Species-rich plant communities characteristic for succession from mesotrophic open water to fen are very rare in The Netherlands. These vegetation types used to occur in turf ponds in the low lying peatland area, created by peat dredging and filled with water due to seepage of mesotrophic, well-buffered groundwater. One of the goals of the National Nature Policy Plan is to create new opportunities for the initial terrestrialization communities through ecological engineering, e.g., restoration and creation of open water habitats. Restoration of the abiotic conditions in acidified floating fen communities is only possible by a combined measure of removal of the Sphagnum-layer and superficial drainage of surplus rain water. New turfponds have been excavated. This study showed that the abiotic conditions (i.e., water depth and water chemistry) are favorable for the development of aquatic communities characteristic of mesotrophic conditions. The aquatic plant species found in the new ponds also point in this direction, e.g., Chara major and Ch. delicatula are very abundant as are seven Potamogeton species. It is concluded that a constant discharge of groundwater and a good connectivity between the ponds and the existing remnants of plant communities desired in the area are essential for the conservation and development of these species-rich plant communities.