Dental ecometrics of tropical Africa : Linking vegetation types and communities of large plant-eating mammals

Abstract

Background: The dental characteristics of large plant-eating mammals, such as hypsodonty, quite accurately describe present and past climatic conditions worldwide. However, several peculiar regions give systematically higher predictions of primary productivity than the local average environmental conditions should support. We call these 'anomalies'. Anomalies are prominent in areas dominated by pastoralism, such as the Sahel in Africa, suggesting human-competitive pressure against the wild animal communities. Question: What might explain such dental ecometric anomalies? Data: Occurrence of large, plant-eating mammals worldwide; quantitative characteristics of their teeth; global net primary productivity derived from temperature and precipitation relationships. Analyses: We analyse dental ecometrics of present-day Africa, with the aim to understand the ecology behind such anomalies. By identifying dental traits that are differentially sensitive to human activities, we can develop tailored models for accurate reconstruction of tropical habitats while taking human activities into account. Results: A combination of dental crown height and reinforcement of cusps helps to distinguish continuous, moist forests from patchy forest fragments within arid grasslands. We demonstrate how dental traits that have different sensitivity to competition with livestock can capture anthropogenic effects on wild animal communities in climatically sensitive zones. We produce a methodology for understanding the present and guiding the future of terrestrial ecosystems.