Human health outcomes of a restored ecological balance in African agro-landscapes

Highlights: • Human health facets of invertebrate ecosystem services are rarely assessed. • Invasive species can induce food system collapse and nutritional deprivation. • Biological control fortifies agro-ecosystem functionality and livelihood security. • A restored agro-ecological balance benefits collective societal welfare. • Resilient, biodiverse farming systems are central to human well-being. Biodiversity loss and invasive species are exacting negative economic, environmental and societal impacts. While the monetary aspects of species invasion have been well-assessed, their impacts on human and social livelihood outcomes routinely remain obscure. Here, we empirically demonstrate several important human health and demographic consequences of a 1970s invasive pest species of cassava across sub-Saharan Africa. Pest-induced crop loss in 18 African countries relying heavily on cassava as a staple inflicted cascading effects on human birth rate (−6%) and adult mortality (+4%) over the span of a decade. The 1981 scientifically-guided release of the specialist parasitic wasp Anagyrus lopezi restored cassava yields, thus reconstituting food security in these agricultural systems and enabling parallel improvements in human health indices. Our analysis shows how agricultural performance can influence health and demographic outcomes, and accentuates how deliberate efforts to safeguard agro-ecological functions and resilience could be important during times of global environmental change.