No detrimental effects of soil disturbance resulting from grassland restoration operations on aboveground‐dwelling invertebrate communities

Abstract

Active grassland restoration requires soil disturbance by harrowing or plowing prior to seeding to create favorable conditions for plant germination. Yet, it is still unknown if these soil interventions are detrimental to the local ground‐dwelling invertebrate fauna. We evaluated how ground beetle (Carabidae) and spider (Araneae) communities, two important grassland bioindicators, respond to three common grassland restoration methods, differing in soil disturbance intensity and seed application method. The study was carried out in 47 extensively managed mesic meadows using a before‐after‐control‐intervention design. It was applied at the field scale and replicated 12 times across selected Swiss lowland sites. We did not detect any significant differences in abundance and species richness of ground beetles and spiders between restored and control meadows 1 year after restoration. At the community level we observed a slight shift towards a preference for wetter habitat (for both invertebrate groups), and restored meadows harbored a smaller weighted mean body size of spiders than control meadows. The latter was mainly driven by a higher abundance of some small pioneer species typically found in frequently disturbed habitats, notably in arable fields. Our results suggest that 1 year after restoration action, the ground‐beetle and spider communities recovered almost entirely to their predisturbance state, indicating that, with respect to above ground‐dwelling invertebrates, harrowing or plowing can be applied when restoring plant species‐poor grasslands.