Wet meadow restoration in Western Europe: A quantitative assessment of the effectiveness of several techniques

Techniques such as rewetting, topsoil removal, diaspore transfer or combinations of these are increasingly applied in fen meadow and flood meadow restoration in Western Europe. In this paper, we present a quantitative assessment of the effectiveness of the commonly used meadow restoration methods. We use the change in 'saturation index' to evaluate the degree of success. The index reflects the completeness of restored communities in comparison to regional target communities. Meadow restoration has limited success in most cases, with an average increase in species richness below 10% of the regional species pool. Restoration success was partly determinated by the starting situation. The more species-rich the starting situation, the higher the saturation index after restoration but, at the same time, the smaller the increase in the number of target species due to restoration. Top soil removal and diaspore transfer were found to contribute most to restoration success. A combination of top soil removal and diaspore transfer and a combination of all three techniques appeared to be the most effective measure and resulted in an increase in the saturation index of up to 16%. Rewetting alone had no measurable effect on restoration success.