We examined how plant-pollinator interactions were affected by time since habitat restoration and landscape connectivity by comparing plant-pollinator networks in restored, abandoned and continuously grazed semi-natural pastures in south-central Sweden. We measured richness of flowering plants and pollinators, and local plant-pollinator network characteristics including species composition as well as the number and identity of interactions, allowing a deeper understanding of species and interaction beta diversity. Pollinator richness and abundance were highest in restored grasslands. They successfully resembled continuously grazed grasslands. However, the turnover of interactions was extremely high among pasture categories (0.99) mainly due to high turnover of plant (0.74) and pollinator species (0.81). Among co-occurring plant and pollinator species, the turnover of interactions (0.66) was attributable mainly to differences in the number of links and to a lesser extent to species true rewiring (~0.17). Connectivity and time since restoration had no effect on the measured network properties. We show that plant-pollinator interactions can be rapidly restored even in relatively isolated grasslands. This is partly due to flexibility of most pollinators to establish interactions with the available flowering plants and relatively high species interaction rewiring, indicating that pollinators behavioural plasticity allow them to shift diets to adapt to new situations.

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Questions:Does 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?Location: Agricultural landscapes in south-central Sweden.Methods: The 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 (1-13 yr).Results: The 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.Conclusions: Our 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.

Land‐use change can disrupt associations between different trophic groups, but it is unclear if habitat restoration can recover these associations. In Sweden, restoration efforts have been applied to increase areas of semi‐natural grassland previously remaining as small fragments due to abandonment. We assessed how the associations between plant and pollinator communities can be modified by grassland abandonment and restoration, together with landscape connectivity. We surveyed plant, hoverfly and bee communities in 10 abandoned, 18 restored and 10 intact grasslands in south‐central Sweden, distributed along a gradient of isolation from other species‐rich grasslands. We assessed the effects of management history and connectivity on the relationships between several measures of the composition of plant and pollinator communities as well as between plant community composition and pollinator guilds. The composition of the local flowering plant community was an important determinant of both hoverfly and bee communities. However, plant‐pollinator associations were modulated by landscape connectivity and, to some extent, by grassland management history. Abundance, species richness and functional richness of bees and species richness of hoverflies were positively associated with local plant communities in isolated grasslands, but these associations weakened in well‐connected grasslands. In contrast, hoverfly abundance correlated positively with plant communities in well‐connected grasslands. The response of pollinator feeding guilds was consistent with overall pollinator communities. However, abundance of bees adapted to foraging on particular plants (long‐tongued and short‐tongued) responded positively to specific host plant species abundance. Synthesis and applications. Our results show how land use and landscape context can significantly affect interactions between different trophic levels. Land use and landscape context should therefore be recognised in grassland restoration guidelines. Enhancement of both functional‐rich and species‐rich plant communities, as well as increasing abundance and species and functional richness of host plants for specialist pollinators will amend pollinator diversity. Restoration actions should consider the spatial configuration of the landscape to improve its outcome. Efforts in more isolated grasslands should focus on promoting local habitat quality while, in more connected grasslands, the priority should be maintaining connectivity to well‐preserved grasslands.

After habitat restoration, species need to recolonize from existing populations. The ability of species to recolonize restored habitats likely depends on their traits. This study aimed to test if species traits and isolation from source habitat can explain the presence of insects in restored grasslands. We surveyed the occurrence of hoverflies and bees in 14 restored seminatural pastures as well as in intact seminatural grasslands in the surrounding landscape. We tested how connectivity, time since restoration, and species traits influence if species that are present in the surrounding landscape also occur in restored pastures. Solitary bee species present in the landscape were less likely to occur in restored pastures compared to bumblebees and hoverflies. The occurrence of bumblebees, but not solitary bees or hoverflies, decreased with time since restoration. The occurrence of solitary bees increased but the occurrence of hoverflies decreased with high connectivity. Migratory hoverflies were more likely to occur in restored pastures than nonmigratory hoverflies, especially in pastures with low connectivity. Among both bumblebees and solitary bees, the occurrence was influenced by nesting traits, with the lowest occurrence of parasitic species and of species digging nests in the ground. The subset of the landscape's species pool that occurs in restored pastures has a contrasting set of traits compared with species in intact source habitats. Both mobility and resource use act as filters that influence the assembly of pollinator communities after restoration. A full recovery of pollinator communities is more likely if source populations are available nearby.