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The restoration of hay meadows is one of the major challenges in temperate Europe, to overcome the drastic loss and degradation of these semi-natural habitats. Evaluation of restoration success requires the definition of a relevant reference ecosystem. Historical phytosociological relevés dating from the 1960s–1970s, before large scale agriculture intensification, may be used as the reference framework for such purposes. However, this reference framework may no longer be pertinent in our present-day ecological and socio-economic context. In this study, we assessed the success of three restoration techniques for lowland hay meadows, based on plant species richness and composition and functional traits, by comparing the restoration trajectories to historical and current references. The three restoration techniques, passive restoration mowing, active fresh hay transfer and active sowing of threshing material, were implemented depending on the initial level of degradation and the proximity to well-preserved meadows. The species composition of restored meadows clearly differed from historical references but converged toward current references, for both passive and active restoration techniques. Historical references are characterized by short, stress-tolerant dicotyledonous plant species with small specific leaf area, indicators of nutrient-poor environments. The gap observed between plant communities of historical and current meadows suggests that the historical data are an over-ambitious target for restoration purposes and can hardly be considered relevant to our present-day context. Therefore, creation of a new reference framework of lowland hay meadows is needed for the adequate implementation of restoration projects. Successful outcomes of active and passive techniques must encourage practitioners to adapt the choice of the restoration method depending on the local ecological context, i.e., level of degradation and proximity to well-preserved habitats.

In ecological restoration, especially in projects aiming at introducing a diverse plant community, species that do not establish are rarely reported., Yet, knowledge gained from identifying and understanding the reasons why species did not establish is useful to improve restoration techniques. In this paper, we used Sphagnum dominated peatlands restored with the Moss Layer Transfer Technique (MLTT) as a typical example of restored ecosystems for which information about species that does not establish is lacking. By comparing the plant species pools of 22 pairs of donor/restored Sphagnum peatlands (including 17 sites restored for more than 10 years), we calculated that the proportion of successfully introduced plant species (transfer rate) was 82 ± 9%, amongst the highest transfer rate when compared to other restoration projects. Only five vascular plant species were classified as recalcitrant – species present in the donor site but absent from the restored sites: Carex trisperma, Cypripedium acaule, Ilex mucronata, Maianthemum trifolium and Rubus chamaemorus. Explanations about the filters impeding establishment were mainly based on the autoecology of the species. Depending on restoration goals (e.g. return of edible berries or orchid diversity) we recommend the specific reintroduction of recalcitrant species after the MLTT.

We have developed an approach to restore bogs after peat extraction, but, when sedge-peat layers are exposed, the minerotrophic remnant peat conditions require restoration towards a fen ecosystem. Three restoration techniques, all including rewetting actions, were tested to assist fen vegetation recovery. None of the restoration techniques were effective at establishing fen bryophytes. However, for vascular plants, two techniques gave promising results in terms of species composition, although the vascular plant cover remained lower than in the reference fens. Depending on the site conditions, we suggest applying two restoration techniques to restore peatlands in areas of exposed sedge peat. In areas where sparse cover of fen species may have spontaneously established, rewetting should be carried out to raise water levels and create favourable conditions for their expansion. In areas covered with undesirable species or with inadequate topography for rewetting, surface peat should be remodeled and vegetation introduced. Since mechanized diaspore transfer did not result in a satisfactory cover of fen plants, other means of introduction could be considered, alone or in combination. A complementary fertilization experiment showed that fertilization with phosphorus could be an effective solution to enhance the establishment of mechanically introduced plant diaspores. [ABSTRACT FROM AUTHOR]

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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. [Copyright &y& Elsevier]