Humans have impacted global biodiversity via habitat degradation and destruction, the introduction of invasive species, and direct harvesting of plant and animal populations. The archaeological record provides abundant evidence that modern humans living in small-scale societies are capable of substantial impacts on past ecosystems. The antiquity of human impacts on past environments is much debated, especially concerning the extent to which humans contributed to mass extinctions of megafauna during the past 100,000 years. In this project the coPI will evaluate the hypothesis that human foragers contributed to large mammal extinctions along the southern coast of South Africa during the Pleistocene/Holocene environmental transition, between 12-10 thousand years ago. It is generally agreed that environmental change played an important role in these extinctions, although possible human contributions to the southern African extinctions remain unclear. The research will involve an analysis of faunal remains from southern African archaeological sites spanning the past 125 thousand years. A primary objective is to determine whether Later Stone Age humans (<40 thousand years ago) exerted greater predation pressure on large mammal populations than their Middle Stone Age (~250-40 thousand years ago) predecessors. The coPI will examine dental remains of fossil ungulates to reconstruct the age structures of animal populations and to examine the effects of human predation pressure on wildlife populations through time. In addition, the coPI will determine whether there is evidence for anthropogenic resource depression, a decline in wildlife population densities resulting from human predation pressure, at the time of the southern African extinctions. This will involve an investigation of human subsistence change across the Pleistocene/Holocene transition at Boomplaas Cave, located in the Cango River Valley. The Boomplaas Cave faunal remains will be studied to determine how changes in prehistoric human diet reflect environmental shifts and/or anthropogenic resource depression.
Debate over the possible role of prehistoric human foragers on large mammal extinctions has been underway for over 150 years. While much research has focused on extinctions in North America, Australia, and Eurasia, the extinctions in Africa remain poorly understood. The results of this research will provide new insight into how the combined effects of human activities and environmental change have structured the ecosystems of southern Africa, particularly through their impact on large mammal populations. This project will also establish the time depth of human impacts on animal populations in southern Africa. In turn, this has implications concerning the hunting rights of indigenous peoples and wildlife conservation decisions, especially with respect to the fate of contemporary biodiversity and our attempts to understand and moderate the effects of global climate change.
