The question of transport infrastructures construction is often associated to the issue of territory development policies, especially in developing countries. In a country as Mauritania, immense, arid and mainly inhabited by nomads, transport and mobility constitute a major issue for everyday life. The opening in 2004 of the Nouakchott-Nouadhibou road not only takes on geostrategic, political and socioeconomic dimensions, but also has impacts at three levels: international, national and local. Furthermore, the road gives structure to the Mauritanian space, linking up the two national economic and political capitals. The road lies within the framework of great trans-African road projects, reason of its importance in terms of regional integration. At the local scale, the road runs along the eastern border of the Banc d'Arguin National Park (PNBA). Our surveys' findings show that this road has brought about organizational changes structured around the question of accessibility. On the one hand, the road has increased the movements of persons inside the protected area (fishermen, herders, sub-Saharan migrants, tourists, etc.) and at the same time it has accentuated the sedentarization process at the PNBA peripheries, which remains difficult to manage. On the other hand, it has made easier for the local population the access to social services (health, water and education) and to markets. This new spatial dynamic, inside a territory normally dedicated to Nature conservation, is both considered as a source of environment damaging and as a way of socioeconomic development. This contradiction reveals the difficulty to dissociate the "negative" impact of transport on environment from the "positive" one on human living conditions. It also sheds new light on the difficulty to manage the degree of opening and closing of a protected area. In this research, space is apprehended in its social, mental and natural dimensions. In other words, the thesis explores the different fields of public policies, actors' representations and practices, without forgetting the physical field which constitutes the support of actions.
