ABSTRACT
Located on the fringe between the saharan and the sahelian climatic sector, arid south-eastern Mauritania is conditioned by a single rainy season marked by immense inter-annual variation. The annual precipitation is generally less than 250 mm, with many areas receiving below 100 mm. Due to the tropical trade winds, the dry season extends for approximately nine months between mid-üctober and mid-July, and the short rainy season runs from mid-July to mid-üctober. lack of rain during the rainy season rapidly translates into a temporary degradation of pastures and thus a demand for movement on the part of the nomadic pastoralists inhabiting this landscape.
