The importance of herbivore interactions for the dynamics of African savanna woodlands: an hypothesis
Johan Van De Koppel a1 c1 and Herbert H. T. Prins a2
a1 Laboratory of Plant Ecology, University of Groningen, P.O. Box 14, 9750 AA Haren (Gr), The Netherlands.
a2 Department of Environmental Sciences, Tropical Nature Conservation and Vertebrate Ecology Group, Wageningen Agricultural University, Bornsesteeg 69, 6708 PD Wageningen, The Netherlands.
Current hypotheses to explain dynamic transitions between savanna grasslands and woodlands in Africa focus on grazing by elephant or the influence of fire. Using a simple mathematical model, this paper argues that interactions between small herbivores such as impala or buffalo and large herbivores such as elephant or giraffe may provide a plausible alternative hypothesis. The interplay of competition and facilitation between these types of herbivores could explain transitions between grassland and woodland and vice versa. A review of the literature is presented in support of this hypothesis.(Accepted March 16 1998)
Key Words: competition; facilitation; functional.
c1 NIOO-CEMO, P.O. Box 140, 4400 AC Yerseke, The Netherlands, tel: +31 113 577462, fax: +31 113 573616, Email: [email protected]