Dune fixation by Mulching and palisade improved the ecological restoration of Ambouram Ali dunes (Maine Soroa/ Niger).

Résumé

Abstract Like the Sahel countries threatened by desertification, Niger faces multiple consequences of this phenomenon, which affects all ecosystems. In the department of Mainé Soroa, desertification manifested by the gradual disappearance of vegetation, the formation of living dunes and the silting of the land. Several development projects and research structures are trying to combat these scourges through the fixation of dunes. Which is based practically on mechanical and biological fixation. A questionnaire assessing the socio-economic and environmental impact addressed to the dunes' ecological restoration actors served to collect the social and technical data. Two dune clusters in the same village (site 2016 and site 2017), already restored by the “CARE ONG”, constituted the study sites. A device allowing the soil surface horizon's characterization and the herbaceous cover was installed to enable ecological assessment. The result showed that the sectors under winds were more affluent than those near them. The recovery rate and the amount of dry matter were more significant in the sector's sandy area farthest from the palisade than those exposed to the wind. The average organic matter level at the fixed sites: Site 2016 (0.63%); Site fixed 2017 (0,50%) was higher than that of the non-degraded control site (0,39%). More than 70% of peasants say that the first bright dunes' appearance dates back to the 1970s, precisely after the 1973 drought. All respondents also consider the combination of mechanical and biological to be the most effective technique for fixing the dunes alive because of their complementarity. These results show that ecological restoration by mechanical and biological fixation is possible while guaranteeing the protection and monitoring of the restored site to increase its ecosystems' resilience.