The environment of early modern humans at Border Cave, South Africa: micromammalian evidence

An enlarged sample of micromammalian remains from Border Cave has permitted re-evaluation of vegetational and climatic conditions at the site from its earlier occupation, apparently about 130 kyr B.P. The indication is that vegetation in the region was initially woodland analogous to miombo ( Brachystegia) woodland which today occurs a minimum of 3° latitude north of the site. Rainfall would have been 25–100% higher than it is today and more seasonal, with drier winters. Mean annual temperature may have been similar to or slightly higher than it is today. Thereafter, perhaps in δ 18O stage 5b onwards from around 96 kyr B.P., vegetation and, consequently, rainfall appear to have become much as they are today, namely bush savanna with forest patches supported by rainfall around 800 mm. Temperatures, on the other hand, may have been rather lower than they are today, and it is possible that δ 18O stage 4 is represented during this period. Subsequently, during δ 18O stage 3, the vegetation appears to have been open Acacia nigrescens-Sclerocarya savanna, perhaps preceded by mopane ( Colophospermum mopane), such vegetation types today being found at lower altitudes in neighbouring Swaziland and into the northeastern Transvaal. Rainfall may have been 25–55% lower than it is today and relatively unpredictable while temperatures were marginally lower. These conditions persisted until about 24 kyr B.P. when the cave was apparently abandoned.