Restoration of Rare Bryophytes in Degraded Rich Fens: the Effect of Sod-and-moss Removal

Rich fens are known as biodiversity hot spots among peatlands encompassing many endangered bryophytes. In some European regions, specialised rich-fen bryophytes, including red-listed species, have been outcompeted by expansive Sphagnum species and competitively strong vascular plants. One of the main causes of the rapid succession was a cessation of traditional management such as scything, raking, or occasional grazing. Most of the current rich fens in Central and Western Europe depend on such management-related disturbances because they have been initiated or altered by humans. Removal of expansive Sphagnum species together with tussocks of graminoids is occasionally suggested to reverse the succession to previous rich fen stage before re-establishing the traditional management or its imitation. We carried out such treatment on 31 sites to restore microhabitats for fen-specialised bryophytes. Expansive Sphagnum species declined after the sod-and-moss removal. After one and a half years, the treated plots showed a gradual increase in species richness and abundance of fen-specialised bryophytes, which, however, only slightly increased in total cover. In regions where no Sphagnum species are endangered or legally protected, a sod-and-moss removal is a possible tool for restoration of rich fen vegetation that developed to poor fens because of modern anthropogenic interventions in the agricultural landscapes. However, its repetition after approximately a decade might be required due to the rapid regeneration of expansive Sphagnum species. Yet, further research is needed on the effectiveness and applicability of sod-and-moss removal over a longer period.