Autumn inversion tillage reduces beneficial arthropods and delays their recovery into the following crop growing season

Effects of tillage in arable fields on taxonomic and functional responses of beneficial above‐ and below‐ground arthropod communities are poorly understood. We assessed arthropod communities in 30 conventionally managed crop fields in south‐western Sweden before and after autumn tillage. Treatments consisted of three levels of tillage intensity: inversion tillage, reduced tillage (non‐inversion) and no tillage (direct seeding). Reduced tillage and no tillage are considered conservation tillage practices. All fields were sown with winter cereals in autumn 2019, followed by winter oilseed rape sown in late summer 2020. Tillage occurred between cereal harvest and the sowing of winter oilseed rape. We measured soil mesofauna density, and density, taxonomic, compositional and functional diversity of ground‐dwelling predators. Inversion tillage decreased densities of above‐ and below‐ground beneficial arthropods. Conservation tillage resulted in higher species richness and lower community turnover following disturbance. Community compositional shifts following inversion tillage were characterised by lower community weighted mean (CWM) body size and reduced densities of carabids overwintering as imago in autumn, and higher spider CWM body size in spring, compared with conservation tillage treatments. Inversion tillage reduced spider density and richness throughout the following growing season, while soil mesofauna densities, carabid taxonomic diversity and functional composition recovered by spring. Synthesis and applications : Responses to tillage were taxon‐specific and likely depended on life‐stage and the dependency on structural habitat complexity. Management should balance trade‐offs between retaining local communities, meeting the needs of multiple taxa, and accounting for taxonomic and functional richness over time.