VertigO (Sep 2006)
Dégradation des ressources végétales au contact des activités humaines et perspectives de conservation dans le massif de l'Aïr (Sahara, Niger)
Abstract
The Aïr mountain range is nested inside the Saharan part of Niger. It is populated with approximately 80000 inhabitants depending mostly on local vegetation resources. We aimed to study the relationships between the recent changes in human activities and the level of vegetation resource so as to anticipate a possible lack of resources in an arid region confronted to recurrent droughts. Investigations with local populations and empirical observations showed a rapid degradation of the vegetation related to human activities. Two types of effects are distinguished. First, local people increase pressure on vegetation around the villages, while the intensification of irrigated agriculture threatens the level of belowground water resources. Second, the peripheral urban zones have a growing negative impact on vegetation, especially on wood. In addition, an introduced species, Prosopis juliflora is expanding fast and should be regarded as an invasion process. These changes, if associated with severe droughts, could lead to a quick loss of biodiversity and vegetation resources in the massif. Co-management plans on natural resources including local inhabitants as managers should break this degradation cycle. It would also be consistent to make a better use of ecological knowledge as a restoration/conservation tool. Especially, facilitation between plants, and related nurse effects, can be taken as a relevant tool to restore degraded ecosystems in arid environments.
