Trapping results
The total trapping effort represented 13,283 trapnights, which led to the capture of 3,160 small mammals, including 2590 rodents, 569 shrews (g. Crocidura ) and one hedgehog (Atelerix albiventris ; Table 1). Regarding the specific abundance, exotic species were dominant, with first of all M. musculus (N = 945 captures, 30% of the total captures), then R. rattus (N = 804, 25%). The native shrew Crocidura olivieri (N = 556, 18%), the two species of Mastomys (M. natalensis , N = 308, 10%; M. erythroleucus , N = 278, 9%), Arvicanthis niloticus (N = 141, 4%) and Praomys daltoni (N = 91, 3%) followed. The remaining individuals, determined as Atelerix albiventris , Cricetomys gambianus , Crocidura sp., Gerbilliscus gambianus ,Mastomys sp., Mus (including the subgenus Nannomys ) spp. and Steatomys sp. accounted for ca. 1.2% of the total captures (N = 37). Fig. 1 presents the relative frequencies of these species per locality. Regarding their geographic distribution, the species present in the largest number of localities were, respectively,C. olivieri (N = 39 localities) and M. erythroleucus (N = 33), followed by R. rattus (N = 29), P. daltoni (N = 24),M. musculus (N = 21) and A. niloticus (N = 18). At the same time, the exotic rodents M. musculus (N = 16 localities) andR. rattus (N = 14) were the species more often dominant numerically, far ahead of C. olivieri (N = 7) and M. natalensis (N = 6).