A spatially explicit modelling framework for assessing ecotoxicological risks at the landscape scale: the impact of Bt maize on non-target Lepidoptera as an example system
In this study we first present a generic modelling framework, which has been implemented into the SEHmodel R package (Walker et al., 2015), for assessing spatio-temporal ecotoxicological risks within agricultural land- scapes. It combines (i) tools of stochastic geometry for structuring the landscape (tessellation and marked polygon processes) and describing the exposed individuals (marked point process), (ii) a method based on a convolution product with a dispersal kernel for describing the dissemina- tion of toxic particles from emitting polygons, and (iii) an ecotoxicological equation that describes the toxicokinetics and dynamics of the contami- nants in affected individuals. Then, we consider the case of the impacts of Genetically Modified maize pollen on non-target Lepidoptera and we use our stochastic model and a global sensitivity analysis for assessing the influence of our input parameters (especially those related to the spatial structure of the landscape) on the risk of mortality of exposed individuals. Our results suggest that managing the spatial structure of the landscape would help to reduce of the risk.
Joint work with Emily Walker, Jean-François Rey, Antoine Messéan, Samuel Soubeyrand.