Ecologie pastorale au Sahel

Abstract

Ruminant breeding in West Africa is based on natural resources mainly composed of spontaneous vegetation. Pastoral livestock breeding takes place in savanna areas combining both herbaceous and woody communities. Livestock feed is mainly provided by natural grazing of annual herbaceous plants supplemented by aerial grazing of woody plants. This vegetation is dependent on rainfall both qualitatively and quantitatively and is managed collectively as a common good. In addition to providing fodder resources for ruminant livestock breeding, it supplies many services to local populations such as the production of wood, non-timber forest products, medicinal products, or more global services such as climate regulation. However, the plants in these ecosystems are subject to many factors, above all variations in climate and rainfall. Indeed, the drought episodes of the 1970s and 1980s had a strong impact on the vegetation of pastoral areas. Nevertheless, since the 1990s, a return to a more favorable rainfall regimen seems to be underway, which would induce Sahel’s regreening. Other factors that may influence pastoral vegetation are livestock husbandry practices, the policy of drilling boreholes, the introduction of development means and techniques unsuited to the environ-ment, changes in land use linked to rainfed or irrigated agriculture, the exploitation of forest resources, bush fires and urbanization; all these factors have contributed to the degradation of the natural environment and the disruption of the ecological balance with significant socio-economic effects. Studies targeting this spontaneous vegetation provide a better understanding of the dynamics at work and their consequences on ruminant livestock farming. It is within this framework that the Revue d’élevage et de médecine vétérinaire des pays tropicaux and the “Pastoralism and Drylands Pole” (PPZS) have proposed this thematic issue on pastoral ecology in the Sahel. This issue is introduced by a review describing the responses of vegetation to different climatic and management factors. In addition, one article presents an information system for pastoralists, five articles highlight case studies on the impact of management on pastoral veg-etation in various situations ranging from the Sahelian zone of Senegal to the Sudanese zone of Benin, and two articles revisit two approaches related to human sciences and the management of species and spaces with pastoralist communities.These works show that livestock activities have impacts on vegetation. Being most of the time commonly used, the pastures studied are managed collectively at the scale of a territo-ry where actions, interactions and feedback between the influence of livestock activities and decision-making processes with regard to these activities are key factors for sustainable livestock development in the Sahel.