Climate change is a threat to food security. A substantial body of research supports this conclusion for climate change threats to plants with agricultural value, as well as wild-harvested food from animals, such as fish. However, much less is known about climate change threats to wild-harvested food plants despite these species meeting important dietary needs for a large number of households in developing countries, especially when crops fail or during other times of hardship. My study was the first to look at climate change risk to a broad group of wild edible plants and focussed on the wild food plants (WFPs) of southern Africa. The aims of my study were to determine where WFPs occur in southern Africa; whether these WFPs will be threatened by climate change; and how climate change risk for WFPs intersects with climate change risk to staple crops. Species distribution models were used to obtain the historical geographic range of 1190 WFP species and to make projections of range change for 2070 under both low (Representative Concentration Pathway (RCP) 2.6) and high (RCP 8.5) greenhouse gas emissions scenarios. I also mapped percentage change between historical and future yields for maize and sorghum to identify regions where both crops and WFPs, or just one of these are at risk from climate change. WFP species richness in southern Africa generally increases from west to east across the region, with the Eastern Cape, Kwazulu-Natal and Mpumalanga provinces of South Africa having the highest WFP species richness. It is projected that for RCP 2.6, 40% of WFP species will experience a decrease in range extent within southern Africa, increasing to 66% of WFP species for RCP 8.5. For RCP 2.6, the loss of suitable climatic conditions is projected to decrease local WFP species richness most in the north-eastern parts of southern Africa, while increases in WFP species richness are projected in the south and east of South Africa. For RCP 8.5, decreases of more than 200 species are projected for multiple regions in north-eastern South Africa, and local WFP species losses of more than 50% are projected for most of Botswana. Despite these decreases, WFPs could still play an important role in food security during times of low agricultural yield as a result of changing climate conditions, especially in low-income, rural communities that are reliant on smallholder farming. For instance, in parts of the Eastern Cape province of South Africa and northern Namibia, WFP species richness is projected to increase while maize and sorghum yield are projected to decrease. People may be more able to rely on WFPs as a nutritional safety net in these regions into the future. This safety net, however, may be lost in large regions of South Africa's North West and Free State provinces, on the north-eastern border between South Africa and Botswana, as well as parts of northern Namibia, where declines in both crop yield and WFP species richness are projected. This research could prove valuable for climate change adaptation planning, especially in more vulnerable rural regions of southern Africa. Furthermore, by integrating traditional knowledge of WFPs into food security risk assessments and response options, it could provide a more inclusive range of food supply options people can use in order to mitigate risk. However, in order to ensure future food security, more research is needed on WFP uses, nutritional value, responses to climate change, and suitability for cultivation. Still, by looking beyond the farm level and conventional crops to the exceptional diversity of WFPs people obtain from their environment, my research has made a first step towards understanding the linkages between WFPs, agriculture, food security, and climate change.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/36235 |
| Date | 22 March 2022 |
| Creators | Wessels, Carina |
| Contributors | Trisos, Christopher |
| Publisher | Faculty of Science, Department of Environmental and Geographical Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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