The RODENT program: Impacts of anticoagulant rodenticides on ecosystems – adaptation of target rodents and effects on their predators

Anticoagulants (AVKs) are used worldwide for rodent control, the European regulation authorizing their use as biocides (non-agricultural use at the vicinity of houses) and pesticides (agricultural treatments in fields). AVKs induce adaptations by selection of resistant genotypes in target populations and the poisoning of rodent predators with possible impacts on populations. Here, we present the RODENT program which aims at (1) determining critical parameters of resistance fixation in rodent populations; (2) assessing which factors control AVKs transfer to small mammals in natura and measure impacts on predators (red fox). Several sites are selected in Eastern France according to the dominant AVK use (biocide vs pesticide) and human habitat type (rural vs urban). The prevalence of VKORC1 mutations will be quantified in rats and linked with the characteristics of the studied populations (size, isolation...), human habitats and treatments. In each site, the spatial distribution of AVK accumulation in small mammal community will be described over time. Relationships between resistance and bioaccumulation will be quantified in rats. Concerning predators, non-invasive markers of AVK exposure are under development for the red fox. This will allow determining factors influencing population exposure. Finally, the dynamic of fox populations will be monitored and linked with AVK use, rodent accumulation and exposure at local and regional scales. Based on collaboration with institutions and professionals, this program will contribute to develop new management methods to limit (1) fixation and diffusion of resistance in target rodents and (2) impacts of AVKs on predators. RODENT is funded by the French Agence Nationale de la Recherche from 2009 to 2013