Does agricultural landscape influence rodents and ticks abundances and their interactions?

International audience

English. Rodents and shrews host many infectious agents potentially pathogenic for humans and livestock. In vector-borne disease systems, vertebrate hosts are resources for vector populations and reservoirs for some pathogens. The distribution and abundance of both hosts and vectors rely on habitat availability. Changes in land use and agricultural intensification (e.g. removal of hedgerows, field enlargement) tend to reduce availability and connectivity between remaining permanent habitat patches and may therefore have consequences on animal populations and the transmission of zoonotic diseases. Rodents are a key component in tick-borne disease systems, as important hosts for larvae of several tick species (including the most common one, Ixodes ricinus) and as reservoirs of several tick-borne pathogens (e.g. Borrelia burgdorferi sl. and Babesia microti). To investigate the influence of spatial heterogeneity in agricultural landscape on this system, we evaluated in spring and autumn for two consecutive years the abundance of rodents and questing ticks along a landscape gradient. Sampling plots included forest habitats and wood/hedgerow-meadow ecotones in four different farming landscape contexts. Despite marked variations of abundances between plots, preliminary analysis did not show a clear landscape context effect at large scale, suggesting a complex influence of the landscape at the local scale that will be evaluated by GIS tools and multivariate analysis. The consequences on pathogen transmission could be further assessed by the detection of some pathogens in vectors and hosts