Recovery of plant diversity in restored semi-natural pastures depends on adjacent land use

QuestionsDoes restoration success of formerly abandoned semi-natural pastures depend on adjacent land use? Is species richness higher in restored pastures adjacent to an intact semi-natural pasture than in restored pastures adjacent to arable land? Does community similarity between a restored and an adjacent intact pasture decrease with distance from the border between the two pastures? Do differences in species richness and community similarity decrease over time? LocationAgricultural landscapes in south-central Sweden. MethodsThe plant community in previously abandoned but now restored semi-natural pastures was surveyed along a distance gradient from the border between the restored pastures and adjacent fields towards the centre of the pastures. The restored pastures were located adjacent to either a crop field (N=8) or a continuously grazed pasture (N=6), and differed in time since restoration (1-13yr). ResultsThe total species richness was higher in pastures adjoining continuously grazed pastures compared to crop fields. Richness of both total and specialist species increased with time since restoration. Irrespective of adjacent land use, richness of specialist species decreased with increasing distance from the edge, an effect that became weaker with increasing time since restoration. The similarity in species composition compared to that in adjacent continuously grazed pasture also decreased towards the centre of the restored pasture. ConclusionsOur results suggest that restoration of biodiversity in semi-natural pastures benefits from adjacent pastures that can act as source habitats. The most likely mechanism is step-wise short-distance dispersal, but also other processes, such as more long-distance dispersal, seed bank dynamics and historical legacies are probably involved. To best succeed in habitat restoration in fragmented landscapes, the spatial location of source populations must be considered.