Mid- to late-Holocene vegetation dynamics on the Laikipia Plateau, Kenya

Abstract

Interactions between Holocene environmental changes and human subsistence strategies in semiarid parts of eastern Africa are relatively poorly understood because of a paucity of sites where contemporaneous archaeological and palaeoenvironmental records are preserved. This paper presents new AMS14C-dated palaeoenvironmental evidence of midto late-Holocene vegetation changes, in the form of pollen, charcoal, mineralogical and δ13Cbulkdata, from a floodplain location on the Laikipia Plateau, Kenya, and in the context of information on modern plant-environment relationships, existing and new archaeological and historical data, and published palaeoclimatic records. Although relatively poorly resolved, the evidence indicates more wooded and relatively humid conditions compared with the present from before c. 6600 BP to c. 1900 BP. Evidence for vegetation changes over the last two millennia is more finely resolved and indicates increased burning and the expansion of fire-modified Acacia bushland c. 1900 BP and grassland c. 1700 BP. Burning to improve and extend pasture, and possibly to eradicate diseaseprone habitats, may have been facilitated by prolonged periods of moisture deficits that might also have facilitated the spread of food production technologies. Vegetation changes c. 700 BP are associated with evidence for the occurrence of fires locally and could represent the activities of people and their animals close to the study site.