Assembly of Ungulate Communities as an Outcome of Interspecific Interactions Over Ecological and Evolutionary Timeframes

What factors determine the distributions of species is a fundamental question in ecology. The distribution of a species is influenced by its environment, but also by its interactions with other species through processes such as competition or facilitation. However, the relative importance of these interactions, particularly at large spatial scales, remains a source of debate. This thesis examines this question in a diverse group of mammals, the ungulates (Artiodactyla and Perissodactyla), focusing on the species-rich communities of the Afrotropics and considering this question first at broad, and then at fine, spatial scales. The first data chapter (Chapter 2) uses joint species distribution modelling to estimate the role of biotic effects alongside climate in determining the species distributions of ungulates across the Afrotropics. While climate appears to be the predominant factor, my results suggest a significant role also for biotic factors and/or barriers to dispersal in community assembly. Chapter 3 also uses joint species distribution modelling, but at a considerably finer resolution, looking at the distribution of wild and domestic ungulates in Bale Mountains National Park in Ethiopia, with direct implications for the conservation of the endemic mountain nyala (Tragelaphus buxtoni), for which the park is the major stronghold. I found that the mountain nyala appear to segregate spatially from livestock beyond what is expected from the environment, suggesting competition or behavioural interference between these populations. Chapter 4 directly builds on the results of Chapter 3 by looking more closely at the response of mountain nyala to anthropogenic disturbance, including livestock, using playback experiments. I found that mountain nyala are significantly more disturbed by domestic cattle, sheep, human pastoralists and domestic dogs, than by a control stimulus, indicating that the spatial segregation observed in Chapter 3 may be driven by disturbance. Chapter 5 examines geographical variation in stripe patterns in a genus of African ungulates, the tragelaphines, or spiral-horned antelopes. I found that, contrary to common assumption, there is limited evidence that these stripes have evolved for camouflage and instead find strong evidence that the primary purpose of these stripes is to deter disease-carrying biting flies. Overall, this thesis integrates joint species distribution modelling approaches with field biology to examine the factors shaping ungulate distributions in the Afrotropics, with a specific local case study of significant conservation importance. These findings enhance our understanding at a time when wildlife populations are increasingly shifting their distributions in response to anthropogenic climate change and other human pressures, thereby increasing our ability to predict and plan for these changes.