Black rat invasion of inland Sahel: insights from interviews and population genetics in south-western Niger

• Published in: Biological Journal of the Linnean Society
• Main Authors: Berthier, Karine, Garba, Madougou, Leblois, Raphael, Navascués, Miguel, Tatard, Caroline, Gauthier, Philippe, Gagaré, Sama, Piry, Sylvain, Brouat, Carine, Dalecky, Ambroise, Loiseau, Anne, Dobigny, Gauthier
• Other Authors: Unité de Pathologie Végétale (PV), Institut National de la Recherche Agronomique (INRA), Université Abdou Moumouni Niamey, Direction Générale de la Protection des Végétaux, Ministère de l'Agriculture du Niger, Institut de Biologie Computationnelle (IBC), Institut National de la Recherche Agronomique (INRA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de Biologie pour la Gestion des Populations (UMR CBGP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD France-Sud )-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Centre Régional AGRHYMET (CRA), Laboratoire Population-Environnement-Développement (LPED), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU), partnership agreement (number 301027/00) between IRD and the Republic of Niger;SRC-IRD research bursary for international mobility (2011–2012)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Africa; urban habitat; Rattus rattus; trade-mediated invasion; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDE.ES]Environmental Sciences/Environmental and Society; [SDE.MCG]Environmental Sciences/Global Changes
• Online Access: https://amu.hal.science/hal-01463818; https://amu.hal.science/hal-01463818/document; https://amu.hal.science/hal-01463818/file/Berthier%20et%20al_2016%20-%20Black%20rat%20invasion%20in%20SW%20Niger.pdf; https://doi.org/10.1111/bij.12836

International audience Human population migrations, as well as long-distance trade activities, have been responsible for the spread of many invasive organisms. The black rat, Rattus rattus, has colonized most of the world following ship-mediated trade. Owing to its tight association with human infrastructures, this species has been able to survive in unfavourable environments, such as Sahelian Africa. In this work, we combined interview-based and population genetic surveys to investigate the processes underlying the ongoing invasion of southwestern Niger by black rats, with special emphasis on the capital city, Niamey. Our trapping and interview data are quite congruent, and all together point towards a patchy, but rather widespread, current distribution of R. rattus. Genetic data strongly suggest that road network development for truck-based commercial flow from/to international harbours located in neighbouring countries (Benin, Togo, and Nigeria) facilitates the passive dispersal of black rats over a long distance through unfavourable landscapes. Another potentially, more ancient, invasion route may be associated with boat transport along the Niger River. Human-mediated dispersal thus probably allows the foundation of persisting populations within highly anthropized areas while population dynamics may be more unstable in remote areas and mostly depends on propagule pressure.