The ecological context of the Acheulean to Middle Stone Age transition in Africa.

摘要

The Acheulean to Middle Stone Age (MSA) archaeological transition was an extended and complex process, evidenced by the interstratification of both industries at single sites, the apparent gradation of small handaxes into large points, and the presence of Acheulean and MSA tool types in individual assemblages. This research examines the role of environmental change, which remains a relatively unexplored factor, in relation to the emergence of novel MSA behaviors that characterized the earliest Homo sapiens. Faunal assemblages are used to reconstruct past habitats and test for environmental change at late Acheulean and early MSA sites in East and southern Africa. The ecological context of the archaeological transition is compared at two geographic scales: local (individual sites that span the transition---Olorgesailie, Kenya and Cave of Hearths, South Africa) and regional (multiple sites in East and southern Africa).;The method used to investigate habitats is ecological structure analysis based on the trophic (feeding) adaptations of large-mammal fauna. Previous paleoenvironmental analyses of middle Pleistocene faunal assemblages have suggested landscape variability in the East African Rift Valley and grassland continuity in the southern African interior (Potts & Deino 1995; Potts 1998a,b; Brink 2005). These ideas are tested through faunal assemblage comparisons designed to distinguish changing and continuous habitat types through time.;Cave of Hearths, South Africa, and Olorgesailie, Kenya, are two of the rare sites that preserve fauna with both late Acheulean and early MSA archaeological assemblages. Analyses of the fauna suggest distinct regional patterns surrounding the archaeological transition, with grassland continuity in the central interior of southern Africa and landscape variability in East Africa. A regional analysis of multiple Pleistocene faunal assemblages from East and southern Africa conforms to this perspective.;Distinct environmental conditions in East and southern Africa during the Acheulean to MSA transition have important implications for the development of novel MSA behaviors. Patchier and/or less stable environments have significant consequences for human behavior with respect to managing risk, which represents the probability of failing to obtain necessary resources and is associated with resource depletion, environmental change, and the colonization of previously unoccupied landscapes. The development of novel MSA behaviors are examined in the context of adaptive conditions and selection pressures. Assessing the nature of any environmental change is the initial step in a research program investigating the influence of environmental conditions on the Acheulean to MSA transition, and future research goals generated from the dissertation results are presented.