Climate change risk to southern African wild food plants

Abstract

Climate change is a threat to food security. Wild-harvested food plants (WFPs) are important for the diets of millions of people and contribute to food security, especially in rural and low-income communities, but little is known about climate change risk to WFPs. Using species distribution models, we examined climate change risk to 1190 WFP species used by 19 native language groups in southern Africa. We project that 60% of species will experience an increase (40% a decrease) in range extent within southern Africa by 2060–2080 under a low warming scenario (Representative Concentration Pathway (RCP) 2.6), while range reductions for 66% of species are projected under a high warming scenario (RCP 8.5). Decreases in geographic range are projected for > 70% of WFP species traditionally used by some language groups. Loss of suitable climatic conditions is projected to decrease WFP species richness most in north-eastern southern Africa—with losses of > 200 species—while increases in species richness are projected in the south and east of South Africa. Availability of WFP species for food security during lean times is also projected to change. In south-eastern South Africa, local diversity of WFPs is projected to increase, while maize and sorghum yields decrease. However, this potential WFP nutritional safety net may be lost in central parts of the region, where declines in both crop yield and WFPs are projected. By looking beyond conventional crops to the exceptional diversity of WFPs, this research helps understanding linkages between WFPs, traditional knowledge, food security and climate change adaptation.