Floodplain meadow restoration revisited: Long-term success of large scale application of diaspore transfer with plant material in restoration practice

Abstract

Rare and endangered floodplain meadows have been a focus of previous restoration projects, but knowledge about the long-term development of newly created meadows is scarce. We studied the long-term development of sites restored via the transfer of seed-containing plant material on former arable fields and former species-poor grassland. We analyzed the long-term development of the vegetation and tested the differences between former land-use types and former preparatory treatments. In former arable fields, we studied the influence of sowing with a grass seed mixture. In former species-poor grassland, we tested the effect of topsoil disturbance by rotovation to inhibit competition by the resident grassland vegetation.Restoration was generally successful with mean transfer rates (number of meadow species at restoration site/number of meadow species at donor site) of 60%, increased species richness, and high proportions of plant material species in the vegetation. Transfer rates were similar between arable fields and former species-poor grassland, though the number of target species for restoration (typical and/or endangered species) was higher in former arable fields. Communities on grassland sites developed more slowly but were more resilient against flooding. Sowing the grass seed mixture had no influence on restoration success on former arable fields, and the positive effects of rotovating on former species-poor grassland decreased over time. We conclude that the transfer of seed-containing plant material is an adequate method to restore species-rich grasslands that are resilient enough to persevere under floodplain dynamics.