Large areas of northern Mauritania are occupied by mainly nonvegetated arid land cover types which are quite stable over time. For this reason, only the southern part of the country (south of approximately 18 degrees north latitude) was mapped.
Steppe is the dominant land cover type in southern Mauritania, occupying 50 percent of the mapped area. The second most common are sandy areas, which made up almost 25 percent of the mapped area in 2013, and, in descending order, bare soil, Sahelian short grass savanna, rocky land, and wetland and floodplain, all of which occupy between 1 percent and 10 percent of the mapped area. Less than 1 percent is mapped as agricultural land. This makes Mauritania the least cultivated country of the 17 West African countries. Likewise, other“bioproductive” land cover types — forest, gallery forest and swamp forest — make up only tiny fractions of the land area. Although these bioproductive land cover types are small in area, their importance in both ecological and economic terms is large.
The overall rate of change in land use and land cover has accelerated from 0.4 percent per year between 1975 and 2000 to 0.7 percent per year between 2000 and 2013. Compared to the annual rates of change for the entire region of West Africa — 0.6 percent and above 1 percent, respectively — the land cover in Mauritania has changed relatively slowly. Lower rural population densities in Mauritania compared to the average in the region might offer one explanation for the relatively slower conversion of land use and land cover.
Over both time periods, the two most widespread natural vegetation cover types and important pasture grounds, steppe and Sahelian short grass savanna, were affected by the largest losses in terms of area. Almost 19,000 sq km of steppe were lost between 1975 and 2000, and over 15,000 sq km between 2000 and 2013. For Sahelian short grass savanna, these figures amount to over 12,000 sq km from 1975 to 2000 and almost 11,000 sq km from 2000 to 2013. Steppe has given way to large swaths of sandy areas — an expression of the classic picture of desertification, where productive and stabilizing vegetation cover is lost and sandy substrate mobilized, giving the impression of an encroaching desert. Sahelian shortgrass savanna, on the other hand, has largely been replaced by steppe, and to a much lesser extent by sandy area. These changes point to a progressive aridification and subsequent southward shift of the major vegetation cover types in southern Mauritania.
In addition to those changes of large geographic extent, some changes smaller in area are nonetheless significant due to their very high change rates. These include settlements, the area of which increased by a factor of ten between 1975 and 2013 (see Nouakchott), as well as agriculture. The area of rainfed agriculture more than tripled, whereas irrigated agriculture increased almost six-fold over the same time period. The rate of agriculture expansion dramatically increased between 2000 and 2013, reaching an average of 89 sq km of additional cropland each year. In contrast, the already small but ecologically important areas covered by forest and gallery forest have been reduced by 44 percent and 30 percent, respectively, due to drought and agricultural pressure. Mauritania’s forests are all located in the Senegal River Valley, whereas the remaining gallery forests are also found along some of the permanent and ephemeral tributaries to the Senegal River, such as the Gorgol, with very few occurring along the wetlands of southeastern Mauritania. The disappearance of forests is concerning, because they constitute hotspots of biodiversity in this predominantly arid country and offer important habitat for wildlife, including migratory birds, as well as repositories of medicinal plants. By contrast, another land cover type of high significance for biodiversity, the wetlands, has been remarkably stable over this almost 40-year period (see Ephemeral Wetlands).