Assessing the consistency of control activities with priority zones for aquatic invasive rodents in Western France

Aquatic invasive alien rodents (AIAR) pose a serious threat to ecosystems leading to significant economic, environmental, and public health concerns. In France, AIAR populations are well established, and eradication is not possible. Thus, a permanent control program has been implemented in several regions to mitigate their impacts. However, comprehensive assessment of the current management strategies and field implementation remains limited. This study aimed to examine whether the control activities (i.e. trapping) among 2021 and 2023 targeting coypus and muskrats and coordinated by the local One Health entity for pest species aligned with the priority action zones defined in December 2020 by the regional governmental watershed agency. Our study shows that the estimated risk for municipalities of being impacted by AIAR did not translate into a higher density of volunteer trappers involved in control activities allocated to municipalities. On the contrary, an increase of the estimated risk in a municipality was associated with a decrease of removed AIAR per year per trapper. Finally, although trappers set their traps in municipalities with high amount of built-up areas, landscape factors such as the density of watercourses and area of riparian grasslands in the municipality do not contribute to explain the mismatch between the distribution of the efforts of control activities and the zonation of priority areas. To strengthen the strategic approach to AIAR management, our results highlight the need for a more robust collaborative framework among stakeholders, including local and regional governmental authorities, field operators and scientists.