The importance of large trees for grazing ungulates in African savannas

• Applicant: Dr. Anna C. Treydte
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2005 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5455721

African savannas accommodate a high diversity of wildlife species utilising a mosaic of heterogeneous vegetation structure. Varying rainfall patterns and soil fertility create a continuous herbaceous layer, interspersed by large savanna trees. These trees can increase the nutrient content of their understorey vegetation and thereby generate attractive feeding sites for grazing wildlife. Large tree cover, however, is declining due to increased logging activities and elevated elephant densities in some protected areas. This may lead to a decline in the abundance of herbivorous ungulates that optimise their food intake by choosing high quality forage. We compile data on plant nutrient contents collected in Eastern and Southern Africa, together with estimates about minimal nutrient requirements of wild ungulate species. We will compare the nutrient quality of grasses underneath canopies with grasses in open savanna areas and use linear optimisation models to identify the importance of tree environments for grazing ungulate species. We hypothesize that these species will preferably feed beneath canopies due to the low quality of fodder grasses in surrounding savanna grasslands. We will combine information on different savannas along a gradient of rainfall and soil nutrient content with geographic maps of Africa. We then can identify areas where wildlife use underneath canopies should be high. Hence, we can predict future patterns of wildlife abundance with respect to tree cover in different savanna types such that management and conservation decisions can be applied accordingly.

• DFG Programme: Research Fellowships
• International Connection: Netherlands
• Host: Professor Dr. Herbert H. T. Prins