Climate Change Research
Predicting vegetation change across landscapes

Aloe marlothii subsp. marlothii distribution: current and future

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Possible change in distribution as predicted by different GCMs (Global Change Models)

CSM (Climate Simulation Model)

HadCM2 (hadley Centre with and without sulphates)

How might South Africa's incredible heritage of botanical diversity be affected by climate change? This question is of grave concern as more evidence mounts that climate is indeed changing. This NBI research thrust aims to determine the vulnerability of South Africa's botanical diversity to projected climate change and to help plan possible adaptation measures.

The NBI uses a combination of approaches, based primarily on bioclimatic modeling techniques. Put simply, these techniques match the known distribution of plants to the climate in those areas, and then projects how these might shift into the future. Changes in soil water availability and altered incidence of frost occurrence are amongst typical factors considered. Additional non-climatic landscape constraints on how species disperse with changing climatic opportunities includes soil texture and depth, and estimates of land use. These approaches rest heavily on the availability of extensive geo-spatial databases suitable for dynamic GIS analysis.

We are currently developing bio-migration models which are spatially explicit simulation models developed to incorporate species biology in determining how plant distributions will change under expected conditions of climate change.

With the large and growing databases of plant distributions housed within the NBI, we are well positioned to do this work successfully, and are currently funded by globally important conservation groups such as Conservation International and the WWF. We collaborate with leading scientists from around the world. Species level analysis has indicated that species composition is likely to change in all South African biomes with climate change and some biomes may continue to support a noticeably impoverished species mix. The change in species composition could even lead to major vegetation structural changes in some biomes, notably in the grassland biome where virtually the entire existing biome will be susceptible to invading savanna tree species. The majority of the centres of species endemism in South Africa may show significant deterioration of bioclimate, with more than half predicted to experience bioclimatic conditions completely unlike those of today. Conservation areas of the arid west and central parts of the country are also likely to experience a complete alteration of climate, while those of the eastern and highland regions are subject to less severe change.

A number of publications has been generated from this sub-programme. In January 2000, the Climate Change Research Group (in collaboration with the Botany Department of University of Cape Town) submitted to the National Climate Change Office the final report on the Plant Biodiversity Section of the Vulnerability and Adaptation Assessment Sector of the South African Country Study on Climate Change. This report appeared in popular form in 2001 (The Heat is on...), and a web version can be viewed on this site.

Contact person: Dr M.C. Rutherford: email:

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