Presented here are some aspects of an archaeological investigation conducted in eastern Mauritania in the region of Dhar Nema, a south-eastern extension of the Oualata and Tichitt cliffs (Dhar). This evidence is presented with a focus on its environmental context. The escarpment of the Dhar, a specific geomorphological environment, provided a refuge geoecosystem that continued to supply water during the second part of the Holocene. During the period leading to the current aridity in the southern Sahara, the neolithic populations came there to seek refuge. Amongst more than 70 sites studied, six were chosen that each illustrate a different topographic and ecological context and the interactions of the populations with these. Their location corresponds to varied geological “accidents” oriented perpendicular to the escarpment and in direction of the Baten. In order to survive in this fragile environment during this warming period, the populations developed essential social and technical innovations. These sites have evidenced the characteristics of the evolution of a culture that existed from the 3rd millennium before our era, with notably a social organisation in villages as well as agricultural practices and animal husbandry, which developed from the commencement of their sedentarisation.