Restoration of a species-rich fen-meadow after abandonment: response of 64 plant species to management

. Eleven years of abandonment of a species-rich fen-meadow under undisturbed environmental conditions resulted in transformation into areas with tall herb-, sedge- and rush-dominated communities and areas with Alnus thicket. Species cover was measured in permanent plots in both community types and succession was monitored during 14 yr of restoration following reintroduction of management. The annual increase in accumulated species number followed a log-log-time linear regression during 10 yr of grazing management. The expected number of years taken before this annual rate was equal to annual extinction, i.e. a stable situation according to species density, was up to six. The response of 64 species to management was evaluated through paired statistical tests of changes in cover and frequency over time. In total, 55 species could each be allocated to one unique response model (monotone or non-monotone, concave models) independently of the importance value used (cover or frequency) and type of management (grazing following felling or mowing and mowing without grazing). Species which increased in response to grazing had the most persistent seed banks and CR-strategies, while species decreasing in response to grazing had less persistent seed banks and CS-strategies. Some of the species which increased due to grazing followed a model with a local maximum in cover and frequency. The results are discussed in relation to management of species with high cover value during restoration succession.