Oecologia (2003) 134:560–568 DOI 10.1007/s00442-002-1149-4 ECOSYSTEMS ECOLOGY David H. M. Cumming · Graeme S. Cumming Ungulate community structure and ecological processes: body size, hoof area and trampling in African savannas Received: 25 March 2002 / Accepted: 20 November 2002 / Published online: 30 January 2003  Springer-Verlag 2003 Abstract A wide range of bioenergetic, production, life history and ecological traits scale with body size in vertebrates. However, the consequences of differences in community body-size structure for ecological processes have not been explored. We studied the scaling relation- ships between body mass, shoulder height, hoof area, stride length and daily ranging distance in African ungulates ranging in size from the 5 kg dik-dik to the 5,000 kg African elephant, and the implications of these relationships on the area trampled by single and multi- species herbivore communities of differing structure. Hoof area, shoulder height and stride length were strongly correlated with body mass (Pearson’s r >0.98, 0.95 and 0.90, respectively). Hoof area scaled linearly to body mass with a slope of unity, implying that the pressures exerted on the ground per unit area by a small antelope and an elephant are identical. Shoulder height and stride length scaled to body mass with similar slopes of 0.32 and 0.26, respectively; larger herbivores have relatively shorter legs and take relatively shorter steps than small herbivores, and so trample a greater area of ground per unit distance travelled. We compared several real and hypothetical single- and multi-species ungulate commu- nities using exponents of between 0.1 and 0.5 for the body mass to daily ranging distance relationship and found that the estimated area trampled was greater in communities dominated by larger animals. The impacts of large herbivores are not limited to trampling. Questions about the ecological implications of community body-size structure for such variables as foraging and food intake, dung quality and deposition rates, methane production, and daily travelling distances remain clear research priorities. Keywords African herbivores · Allometry · Body mass · Livestock · Scaling Introduction Communities of large herbivores in African savannas have been radically altered by human intervention over the last two centuries. Herds of domestic animals, often composed of single species, have replaced the more diverse indigenous herbivore communities over very large areas. In southern Africa the biomass of cattle is now about 16 times that of elephants and exceeds the total biomass of wild ungulates by a factor of 6 (Cumming 1999). Relatively intact large herbivore communities remain in about 10% of savannas, but these communities are frequently subject to intensive management and may suffer from the overpopulation of species such as elephant (Cumming et al. 1997). In many protected areas in Africa, managers must make decisions about the population sizes and species composition of large herbivore communities that will result in the most sustainable and effective long- term conservation of biodiversity or use of available resources. Similarly, ranchers must decide on the optimal composition of their herds to produce high, sustainable yields, and may be faced with a choice between indigenous and domestic herbivores, or a mix of both. The problem has two central aspects: the total biomass of herbivores that the local climate and vegetation can support (Coe et al. 1976; Fritz and Duncan 1994), and the partitioning of this biomass between different species. Although four female elephants weigh about the same as a herd of 50 sable antelope, their ecological effects will be vastly different. Much of the extant work on body size and its ecological consequences has concentrated on individual species and variations in behaviour and life history between species of differing body size (Western D. H. M. Cumming ( ) ) Tropical Resource Ecology Programme, Department of Biological Sciences, University of Zimbabwe, P.O. Box MP167, Mount Pleasant, Harare, Zimbabwe e-mail: dcumming@science.uz.ac.zw Tel.: +263-4-776497 Fax: +263-4-333334 G. S. Cumming Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA