In the Sahel, the question of interactions between rangeland herding practices and the environment lies at the hert of the debate concerning sustainable development. There is disagreement about the question of Sahelian herd mobility, which remains necessary for some while for others it is outmoded, and which is judged in terms of its environmental impact. There are also many questions regarding the influence of socio-economic policies on herder behaviour. [...] We performed two modelling experiment on the theme of mobility as a means of adaptation. The first experiment studies the relation between movement strategies and the dynamics of resources in space, while the second studies the social relations maintained by herders in order to botain access to rangelands and water. To this end, we used the multi-agent modelling method. This method is based on the representation of entites which interact directly with each other or via the environment. In this article, we present the methods and describe the two modelling experiments. We conclude with a discussion on the use of such models.