Analysing and predicting the impacts of agroecology expansion on natural pest control services in agricultural landscapes

Abstract: Designing agroecological landscapes promoting ecosystem services, such as natural
pest control, represents a promising avenue for limiting the environmental footprint of
agriculture. However, the consequences of large-scale deployment of agroecological practices
(AP) on natural enemy communities and pest infestation levels remain poorly investigated,
resulting in uncertain predictions. Using multiple case studies (e. g. vineyards, apple orchards, maize and wheat crops) in the Nouvelle-Aquitaine region (France), this PhD thesis will explore the consequences of the large-scale deployment of AP on the structure of multi-trophic natural enemy communities and the level of pest control service. The main objectives are (i) to quantify and rank the effects of key environmental and biotic drivers of natural enemy assembly, biological control potential and pest pressures at the field and landscape scales, and (ii) to assess and compare the predictive ability of innovative statistical models designed to forecast the consequences of different scenarios of land-use change on natural pest control at the regional scale. The originality of this work lies in several aspects, notably in: (i) developing an integrative, multi-scale approach to natural pest control; (ii) explicitly quantifying the causal relationships between environmental changes, natural enemy community structure and the level of pest control; and (iii) developing predictive approaches to help design functional landscapes minimizing pesticide dependency.