Effect of Connectivity Between Restoration Meadows on Invertebrates with Contrasting Dispersal Abilities

Schemes to restore farmland biodiversity are often implemented at field scale whereas landscape scale factors are not considered. In a grassland dominated region in Switzerland, we tested whether the landscape factor habitat connectivity could possibly increase the effectiveness of an agri-environment scheme for meadows. We investigated two indicator groups with contrasting dispersal abilities, land snails and orthopterans (grasshoppers). We investigated 27 extensively managed meadows grouped into nine blocks. Each block consisted of three meadows differing in structural connectivity and land use history: one meadow represented long-term, semi-naturally managed calcareous grassland that was considered as the potential source habitat. The other two meadows were restoration meadows, created 4-6 years ago. One of these restoration meadows was adjacent to the potential source meadow, the other isolated from it. We found a significantly higher species diversity of both invertebrate groups in the potential source meadows compared to the restoration meadows. Communities of both taxa were more similar to the potential source meadows in connected than in isolated restoration meadows. The species diversity of bad dispersers was negatively affected by isolation, but the diversity of good dispersers was unaffected. With respect to individual species occurrences, however, even good dispersers were negatively affected by isolation. We conclude that structural connectivity of restoration meadows to potential source habitats is important for increasing the restoration success of invertebrate communities, particularly of those containing species with limited dispersal abilities.