Mammals’ use of forest-cashew-rice mosaics in West Africa is modulated by their trophic guild

Abstract

Abstract Over millennia, mammals have co-existed with humans across the forest-savannah mosaics characterising part of West Africa. While some savannahs have long been used for rice cultivation in Guinea-Bissau, both those and forests are now being rapidly converted into cashew monocultures. To understand how species cope with such land-use changes, we investigated how mammals make use of forest patches, cashew orchards and rice paddies over two contrasting periods: at the start and at the end of the rainy season. Using camera-trapping, we examined mammal diversity and trophic guild activity across seven landscapes, each comprising three sampling sites located on each of the habitat types in Northern Guinea-Bissau. Based on 937 records from 21 species, species richness and activity were similar across habitat types, but generally higher at the end-rainy season. Species composition differed between the two forestry habitats and rice paddies. At the guild-level, carnivores increased in activity in forests at the start-rainy season, activity decreased in cashew orchards at the end-rainy season for insectivores and at the start-rainy season for herbivores, and omnivores increased in activity in cashew orchards. The similar assemblage-wide diversity across habitat types seems to be enabled by the high habitat heterogeneity but likely offset by previous extinctions from the area. Yet, guild-level habitat use suggested that cashew orchards might not sustain functionally healthy mammal assemblages. Habitat change is expected to become more detrimental under drier climates. Limiting cashew expansion while preserving forests is essential to optimize the long-term conservation of mammal diversity in rural West Africa.