The conservation of biodiversity is increasingly justified by claims that human livelihoods are improved through its protection. Nature's ecosystem services do indeed benefit people, but how necessary is a diversity of living things to provide these services? Most studies cited as addressing this question in natural systems do not actually quantify relevant metrics (e.g. species richness) and assess their relationship with services and/or economic benefits. On the other hand, numerous small-scale experimental studies have demonstrated that more diverse systems do indeed tend to function better, but the relevance of these results to much larger, more complex socio-ecological systems is unclear. Keywords: Africa, biodiversity, biodiversity-ecosystem function, community-based conservation, conservancies, economic benefits, ecosystem services, valuation, wildlife.