Biodiversity-pastoralism nexus in West Africa

Biodiversity loss is a pressing challenge. This is particularly so in regions where the pressure on ecosystems is high such as in the Sahel region. This pressure is due, inter alia, to different land uses such as pastoralism. In this context, the present systematic review analyses the state of research on the nexus between pastoralism and biodiversity in West Africa. In particular, it explores the relationships between pastoralism (cf. agro-pastoralism, sylvo-pastoralism, agro-sylvo-pastoralism), on the one hand, and plant diversity, animal diversity, and ecosystem diversity, on the other hand. The paper also analyses the bibliometrics of the research field. A search performed in March 2021 on the Web of Science yielded 205 documents and 73 of them were included in the systematic review. The bibliometric analysis suggests an increasing interest in the research field, especially in Burkina Faso and Benin, but also the weakness of the domestic research system as a large share of the selected documents is authored by researchers based outside West Africa. In general, the scholarly literature shows a negative impact of pastoralism on plant diversity (cf. richness, abundance, composition) and animal diversity (cf. wild herbivorous mammals, predators, birds, insects) in West Africa. However, the literature analysis suggests that the effects of pastoralism are rather mixed. They are context-specific and depend on many factors such as grazing intensity and livestock species. The effects on plant diversity differ between woody (trees and shrubs) and herbaceous species. There is a general trend towards the erosion of indigenous livestock genetic diversity due to uncontrolled mating and cross-breeding. The impacts of pastoralism on ecosystem diversity are mainly due to changes in land use and habitat fragmentation. Further multi-country, comparative studies are needed to better qualify the interactions, complementarities and possible conflicts between the different pastoralism-related land uses and biodiversity conservation in West Africa.