Modeling Carbon Sinks and Sources in semi-arid Environments for a Land Degradation Assessment Approach

Contrary to wetlands or moderate climates, the understanding of carbon exchange between ecosystem and atmosphere in arid and semi-arid environments is more challenging due to the sensible feedback of terrestrial ecosystems to environmental variability. Especially in the savannah regions of South Africa the biomes are strongly affected on the one hand by low and sporadic precipitation and on the other hand by intense land use of livestock farming. This leads to wide degraded areas under the process of desertification and the loss of huge carbon stocks in soil and vegetation. To quantify the carbon sinks and sources in these regions we ran our dynamic vegetation model BETHY/DLR for South Africa which generates maps of Net Primary Productivity, NPP, in spatial resolution of 1 km. These results can help assessing the status and development of land degradation for the whole country of South Africa.