Effect of biodiversity on economic benefits from communal lands in Namibia

P>1. 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. 2. Here, we investigate how biodiversity affects the gains from two ecosystem services, trophy hunting and ecotourism, in communal conservancies of Namibia, an arid country in southern Africa. We used statistical methods to explicitly control for confounding variables so that the effect of biodiversity per se on financial benefits to local communities was isolated. 3. Our results show that biodiversity exerts a positive effect on the economic benefits generated from these two ecosystem services produced on communal lands in Namibia. The richness of large wildlife species is positively related to income derived from ecotourism and trophy hunting after statistically controlling for potentially confounding variables such as a conservancy's geographic characteristics and human population size. 4. Synthesis and applications. Our results demonstrate that the conservation of biodiversity can indeed generate increased services from real-world ecosystems, in this case for the benefit of impoverished rural communities in sub-Saharan Africa. More such studies are needed from various ecological and socioeconomic contexts in order to boost the evidence base for positive effects of biodiversity on ecosystem services.