Summary: | The major aim of this thesis is to develop, apply, and test resource competition theory in the ungulate communities of Africa. Ungulates were chosen because RCT requires a great deal of information about the foraging ecology of the species to be modelled, and foraging ecology in ungulates has probably been subjected to more detailed research than any other animal group. The first chapter reviews the literature on competition in ungulates. Chapter 2 then develops a description of ungulate resources within the RCT framework. This new description efficiently encapsulates many well known features of ungulate foraging ecology. Several ungulate foraging scenarios are then described within the RCT framework in a series of conceptual models. A strong prediction that stable co-existence is possible between species that are sufficiently, but not too much, different in body size, emerges. One of these models, describing competition between topi and wildebeest, is developed more fully and tested using data from the literature. The model predicts the resource supply conditions under which each species can be expected to exclude the other. Co-existence is shown to be promoted by environmental heterogeneity that is generated by the foraging activity of the animals themselves. The modelling approach is developed in chapter 3, with a generic model of resource competition between two species differing in body size. The effect of body size on energetic requirements, intake rate, digestive capacity, and selective ability are integrated within the model. Despite the large literature on ungulate foraging ecology, there remain areas of insufficient knowledge, in particular a quantitative description of the relationship between body size and selective ability. The model predicts that stable co-existence is possible between two species competing for resources.
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