Abstract: The aim of the project is to 1) learn about the ecological role of megaherbivores such as the African elephant (Loxodonta africana) and 2) particularly their significance for the interactions between the nutrient poor and the nutrient rich savannas, and 3) to integrate this knowledge in management of wild natural resources in savanna. Our study area is the Chobe National Park in northern Botswana, where Chobe River, the only natural permanent water in the region, is fringed by a strip of a few km of flood plain and shrub savanna on nutrient rich alluvial soil while most of the area is savannas and woodlands on nutrient poor sand. Because of its huge body size, the elephant can utilise more of the nutrient poor woody vegetation on the sand than any other herbivore, and by doing so nutrients are redistributed in faeces and urine to the surface soil, where it favours more nutrient rich herbaceous plants and the smaller herbivores feeding from such plants. Elephants are water dependent, and spend comparatively much time at the river and in the nutrient rich areas surrounding it. As the food resource there is kept low by smaller herbivores, elephants do not forage much in this area, but import nutrients to it in the form of faeces and urine, favouring the heavily grazed and browsed vegetation and the animals depending on it. It is important in management to realise the significance of elephants for the interrelations between rich and poor savannas and for promoting biodiversity in both.

 

 

Small and large herbivores have different ecological functions (photo C. Skarpe)

 

A publication list will be sent upon request. Central publications are:

  • Kalwij, J., de Boer, W.F., Mucina, L., Prins, H.H.T., Skarpe, C. and Winterbach, C. 2010. Tree cover and biomass increase in a southern African savanna despite growing elephant population. Ecological Applications 20: 222-233. 2010 (abstract)
  • Moe, S.R., Rutina, L.P., Hytteborn, H. & du Toit, J.T. 2009. What controls woodland regeneration after elephants have killed the big trees? Journal of Applied Ecology, doi 10.1111/j.1365-2664.2008.01595.x
  • Makhabu, S.W., Skarpe, C., & Hytteborn, H. 2006. Elephant impact on shoot distribution on trees and on rebrowsing by smaller browsers. Acta Oecologica 30: 136-146.
  • Skarpe, C., Aarrestad, P. A., Andreassen, H. P., Dhillion, S., Dimakatso, T., Du Toit, J. T., Halley, D. J.,
  • Hytteborn, H., Makhabu, S., Mari, M., Marokane, W., Masunga, G., Modise, D.(†), Moe, S. R., Mojaphoko, R., Mosugelo, D., Motsumi, S., Neo-Mahupeleng, G., Ramotadima, M., Rutina, L., Sechele, L., Sejoe, T. B., Stokke, S., Swenson, J. E., Taolo, C., Vandewalle, M. & Wegge, P. (2004) The return of the giants: ecological effects of an increasing elephant population. Ambio 33:276-282

 

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