Predictors of small mammal diversity in human-modified landscapes in West Africa

• Guinean landscapes are succumbing to elevated rates of land-use change. • We assessed the drivers of small mammal diversity in mosaic landscapes. • Species richness is positively influenced by rice paddy coverage (%). • Species abundance increases with % rice paddies and decreases with % cashew orchards. • These results can be used to support biodiversity conservation across West Africa. Tropical landscapes are succumbing to elevated rates of land-use change. In West Africa, the once forest-savanna mosaics covering Guinea-Bissau are now mostly composed of rice paddies and cashew orchards, with some remaining forest patches. Understanding how species cope with such changes remains a challenge across the African tropics. To address this gap, we examined small non-volant mammal diversity in northern Guinea-Bissau. Small mammals were surveyed across 15 sites, including five sites in forest patches, five in seasonally flooded rice paddies and five in cashew orchards. We assessed how each land-use type affects species composition, richness and abundance, as well as how land-use composition and heterogeneity surrounding sampling sites influence species richness and abundance. Based on 3600 trap-nights, we captured 230 individuals representing 11 species. Rice paddies supported distinct species composition. Yet, no differences were observed in species richness and abundance among land-use types. Both species richness and abundance were higher at sites surrounded by a higher proportion of rice paddies. Conversely, species abundance was lower at sites surrounded by a higher proportion of cashew orchards. Likely due to the higher (yet seasonal) trophic resource availability, the extent of rice paddies seems to boost small mammal diversity, including typically open-area species, some of which considered crop pests (e.g., Mastomys sp. , Arvicanthis sp. and Uranomys ruddi ). Cashew orchards, on the contrary, seem to function as sub-optimal habitats, likely offering fewer trophic and structural resources. These findings underscore the importance of maintaining rice paddies while limiting cashew expansion, thereby supporting biodiversity conservation across West Africa.