Long-term vegetation dynamics of African savannas at a landscape level
Savannas cover about 13% of the global land surface and about half of the area of Africa, Australia, and South America. Savannas are ecosystems characterized by tree-grass coexistence. Despite the fact that savannas cover a significant percentage of global land surface, they are poorly studied ecosystems. The general aim of this thesis was to provide new long-term data on the demography (mortality & growth) of African savanna plants, focusing on the long-lived, deep-rooted tree Acacia erioloba which dominates in the Kalahari and in southern African savannas. We also analyzed A. erioloba spacing patterns. Furthermore, a computer model to simulate long-term vegetation and climatic scenarios was used. Lastly, combining all our findings, our aim was to examine savanna tree-grass coexistence. In order to provide us with long-term data of African savanna species we used a combination of aerial photographs, a satellite image, and field work. Our aerial photos were taken in 1940, 1964, 1984 & 1993, while our satellite image was taken in 2001.