PLOS One
  © 2014 Garba et al.

Spatial Segregation between Invasive and Native Commensal Rodents in an Urban Environment: A Case Study in Niamey, Niger

Madougou Garba^1,2,3, Ambroise Dalecky^4,5, Ibrahima Kadaoure⁶, Mamadou Kane⁷, Karmadine Hima², Sophie Veran⁸, Sama Gagare¹, Philippe Gauthier⁵, Caroline Tatard⁸, Jean-Pierre Rossi⁸, Gauthier Dobigny^1,5*

1Centre Régional Agrhymet, Département Formation Recherche, Niamey, Niger
2Université Abdou Moumouni, Faculté des Sciences, Niamey, Niger
3Direction Générale de la Protection des Végétaux, Ministère de l’Agriculture, Niamey, Niger
4IRD, Aix Marseille Université , LPED (UMR IRD-AMU), Marseille, France
5 IRD, CBGP (UMR IRDINRA-Cirad-SupAgro Montpellier), Campus International de Baillarguet, Montferrier-sur-Lez, France
6Centre Régional Agrhymet, USAid/Fews-Net, Niamey, Niger
7IRD, CBGP, Campus ISRA-IRD de Dakar-Bel-Air, Dakar, Senegal
8INRA, CBGP, Campus International de Baillarguet, Montferrier-sur-Lez, France

Abstract. Invasive rodents have been responsible for the diffusion worldwide of many zoonotic agents, thus representing majorthreats for public health. Cities are important hubs for people and goods exchange and are thus expected to play a pivotal role in invasive commensal rodent dissemination. Yet, data about urban rodents’ ecology, especially invasive vs. native species interactions, are dramatically scarce. Here, we provide results of an extensive survey of urban rodents conducted in Niamey, Niger, depicting the early stages of rodent bioinvasions within a city. We explore the species-specific spatial distributions throughout the city using contrasted approaches, namely field sampling, co-occurrence analysis, occupancy modelling and indicator geostatistics. We show that (i) two species (i.e. rural-like vs. truly commensal) assemblages can be identified, and that (ii) within commensal rodents, invasive (Rattus rattus and Mus musculus) and native (Mastomys natalensis) species are spatially segregated. Moreover, several pieces of arguments tend to suggest that these exclusive distributions reflect an ongoing native-to-invasive species turn over. The underlying processes as well as the possible consequences for humans are discussed.

*Corresponding author: * Email: gauthier.dobigny@ird.fr