Forced to migrate - told to return. The case of the Hawaweer pastoral nomads of Northern Sudan

agropastoral systems arid zones cambio social changement social comportamiento humano comportement humain decision making human behaviour human population living standards migration niveau de vie nivel de vida nomadism nomadisme nomadismo oued pastoral society pastoralism pastoralisme pastoralismo population humaine rambla sahel seguridad social social change social security sociedad pastoral soudan sudan toma de decisiones wadi zone aride