Effects of the spatio-temporal arrangement of agroecological cropping systems on generalist predators and biological regulation

National audienceFacing the current agricultural challenges, agroecological systems place ecosystem services at the core of their production processes. Among these services is induced biological regulation, which keeps pest populations below an acceptable level in order to meet agronomic objectives. Despite the fact that this service is the result of an active scientific field, the effects of cropping systems that enhance regulation at supra-parcel scales are poorly understood. It is therefore essential to assess the effect of various cropping systems and agro-ecological infrastructures on natural enemy communities, as well as their resulting biological regulation potential, at broad spatio-temporal scales. In order to address these knowledge gaps, the thesis mobilises long-term agroecological systems: the CA-SYS experimental platform and the SCARABEE network of farmers' plots. These two networks will make it possible to analyse the taxonomic and functional evolution of communities of generalist predators (carabid beetles, spiders) according to the arrangement of agroecological infrastructures (grass and flower strips) and the agricultural practices (especially soil management) used. Finally, an experiment on the spatio-temporal dynamics of generalist natural enemy communities will be carried out on CA-SYS in order to identify the habitats contributing to their production (emergence trap) as well as the flows between adjacent plots (capture-mark-recapture)