Irene Esteban
The reconstruction of past environments and climates is important because they might have led to shifts in habitats and therefore on resource (i.e. plants, animals, freshwater) availability for past hunter-gatherers.
Coastal regions may have provided natural buffers against the effects of localized resource instability triggered by climatic and environmental variability. This is because coastal climates are milder; for example, they have more moderate temperatures than inland areas because of the heat capacity of the ocean, and they also support diverse marine and terrestrial ecologies not found inland, including abundant, diverse and predictable resources like fish, shellfish, sea birds, etc.
However, the fluctuation of sea levels associated to Pleistocene glacial/interglacial cycles influenced coastline movements, and in turn, human populations. In South Africa, coastal occupations during glacial periods is nearly absent on account of shelf habitat loss from subsequent marine transgressions (e.g Cape south coast). The Pondoland region is one of a few places across southern Africa that have narrow and steep continental margins that therefore, restricted coastline movements and maintained relative coastal stability across glacial periods.
Waterfall Bluff rock shelter, in coastal Pondoland, preserves records of coastal human foraging during glacial phases, and mainly the late MIS 3 and LGM, and probably because of its narrow continental shelf. Waterfall Bluff ranks as an ideal site for testing the response of hunter-gatherer technology, subsistence economy, and mobility, in relation to resource availability driven by climatic and environmental conditions.
The P5 palaeoenvironmental team is composed by researchers in various research fields, and specifically in phytolith, (lead by co-director Dr, Irene Esteban), pollen (lead by Frank Neumann), and charcoal (lead by Prof. Marion Bamford and Dr. Alisoun House) analysis carried out at the Evolutionary Studies Institute of the University of the Witwatersrand, South Africa; and leaf wax isotope analysis (lead by Enno Schefuß and Charlotte Miller) carried out at MARUM, University of Bremen, Germany.
The initial palaeoenvironmental work at Waterfall Bluff involves a multidisciplinary study undertaken on a vertical stratigraphic section, which covered the time frame from MIS 3 to the Early Holocene and included deposits that have been dated to the LGM and LGIT (Table 1). Using an integrative approach of biotic and abiotic indicators (pollen, phytoliths, charcoal, macro-plants, plant wax carbon and hydrogen isotope composition) we aimed at determining how the continental shelf coastal plain, hinterland, and each area’s natural resources were influenced by climatic and environmental changes, which, in turn, shaped the resources crucial to hunter-gatherer survival in Pondoland during MIS 3, the LGM and the Last Glacial/Interglacial transition into the Holocene.
Our results indicate low rainfall seasonality resulting in high moisture conditions allowing the development of Podocarpus-Afrocarpus forests on the exposed canyons formed by paleo-rivers in front of Waterfall Bluff during the MIS 3 and LGM, which contracted at ca. 13 ka and probably following post-LGM marine transgressions. During the Early Holocene, human occupations intensified, and plants remains were largely transported into the site by past inhabitants and for a variety of purposes, which might include wood-fuel and medicinal. The palaeoenvironmental signal, although tentative, indicates higher rainfall intensity and seasonality (summer) coeval with an overall increase of coastal forests and C4 mesic grasslands with localized wetland vegetation in the surroundings of Waterfall Bluff.