干旱区生态环境知识资源中心

In order to expand on the potential range of early human experiences and adaptive strategies, it is first necessary to determine the paleoenvironmental signatures for a given region of study. In this paper we report on proxy terrestrial, marine, and sea level data in order to reconstruct past environments of Namaqualand, South Africa, during MIS 6-2. Although this semiarid southern extension of the Namib Desert is a prime area to investigate early modern human adaptive innovations, environmental and human history of Namaqualand has been largely neglected. We present environmental, chronological, and subsistence data from recent excavations at Spitzkloof Rockshelter A, and review equivalent data from other sites in the Succulent Karoo Biome. The presence of handaxes on the landscape point to a pre-MIS 6 presence in the region, but current evidence suggests that a more dedicated human occupation of the region likely began during MIS 5. Subsequent human dispersals into Namaqualand are recurrent but heavily pulsed and typically linked to humid stadial phases when sea levels were lower. We propose that the westward movement of the coastline potentially increased the carrying capacity of the region by promoting the colonization of grasses onto the coastal plain, attracting larger game. The mechanism driving this change can be attributed to either an increase in inland precipitation as the Benguela-cooled coastline moved west or reduced evapotranspiration due to lowered temperatures. The strongest evidence for this pattern is during MIS 2 when faunal and floral data indicate a cold but humid environment. Faunal species from Last Glacial Maximum (LGM) layers at Spitzkloof A and Apollo 11 include large ungulates such as Equus capensis, a moisture-loving species that disappears toward the end of MIS 2 (similar to 14 ka) when conditions become more xeric.