Use of native and human-modified habitats by different mammal guilds in West Africa

Abstract

Over millennia, mammals have coexisted 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, savannas 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: early and late rainy season. Using camera-trapping, we examined mammal diversity and trophic guild activity across seven landscapes, each with one sampling site per habitat type in Northern Guinea-Bissau. Based on 937 records from 21 species, species richness and activity were similar across habitat types, but generally higher in the late-rainy season. In this season, species composition differed between the cashew orchards and rice paddies. At the guild-level, carnivore activity was lower in the rice paddies than in forests, while herbivore activity was lower in the cashew orchards in comparison to that in forests in the early-rainy season. The relatively 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 highlighted the fundamental role of forests to sustain functionally healthy mammal assemblages. Maintaining habitat heterogeneity, including patches of native forests, seems to be key in optimizing the long-term conservation of mammal diversity in rural West Africa.

Keywords

• Camera-trapping
• Cashew orchards
• Guinea-Bissau
• Land-use change
• Mammal conservation
• Rice paddies