Elephant-mediated ecosystem processes in Kalahari-sand woodlands
Contribution to Book
Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana
C. Skarpe, J.T. du Toit, S.R. Moe
Wiley-Blackwell and the Zoological Society of London, Chichester, UK
Depending on location and context, the African elephant Loxodonta africana has been classified as either a keystone species or an ecosystem engineer, sometimes both. These classifications arise from the abilities of elephants to break, fell and uproot trees in the course of their feeding activities, with the result that, in combination either with fire or with other browsing mammals, they can transform the structure and function of savanna ecosystems. This chapter explores the functional significance of elephants in the Kalahari-sand woodlands, woodlands that occur on a template of aeolian sands and parallel dune-trough topography. Whereas large herbivore biomass density increases with rainfall across African savannas, the composition of that biomass changes, with elephants dominating in savannas with higher rainfall, lower soil nutrient availability, or both. Elephants therefore have a competitive advantage in dystrophic wooded savannas where they have exclusive use of a major fraction of the primary productivity.
du Toit, J.T., Moe, S.R. & Skarpe, C. 2014. Elephant-mediated ecosystem processes in Kalahari-sand woodlands. Pages 30-39 in: C. Skarpe, J.T. du Toit & S.R. Moe (eds.) Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana. Wiley-Blackwell and the Zoological Society of London, Chichester, UK.