Coping with uncertainty: Neolithic life in the Dhar Tichitt-Walata, Mauritania, ( ca. 4000-2300 BP)

The sandstone escarpment of the Dhar Tichitt in South-Central Mauritania was inhabited by Neolithic agropastoral communities for approximately one and half millennium during the Late Holocene, from ca. 4000 to 2300 BP. The absence of prior evidence of human settlement points to the influx of mobile herders moving away from the "drying" Sahara towards more humid lower latitudes. These herders took advantage of the peculiarities of the local geology and environment and succeeded in domesticating bulrush millet - Pennisetum sp. The emerging agropastoral subsistence complex had conflicting and/or complementary requirements depending on circumstances. In the long run, the social adjustment to the new subsistence complex, shifting site location strategies, nested settlement patterns and the rise of more encompassing polities appear to have been used to cope with climatic hazards in this relatively circumscribed area. An intense arid spell in the middle of the first millennium BC triggered the collapse of the whole Neolithic agropastoral system and the abandonment of the areas. These regions, resettled by sparse oasis-dwellers populations and iron-using communities starting from the first half of the first millennium AD, became part of the famous Ghana "empire", the earliest state in West African history.