Characterization of degraded dune vegetation in south-eastern Niger. Caractérisation de la végétation des dunes dégradées du sud-est du Niger

The degradation of vegetation in the dune environment of the south-east of Niger, a source of proliferation of degraded dunes, is one of the main constraints that places the area in unfavorable conditions of production. Characterization of vegetation of degraded dunes aims to inventory the different forms of dune degradation in order to adopt a specific and simplified restoration plan during dune fixation operations. The study identified four main dune types, including isolated dunes partially fixed, isolated mobile dunes, partially dune fields and mobile dune fields. A total of 27 herbaceous species divided into 13 families were listed in this disturbed environment. The first dominant family is Poaceae representing 43.4% of species and the second families are Cyperaceae and Papilionacceae representing 11.32% of species. Individually, it is the species Bulbostylis barbata and Cenchrus biflorus that have dominant frequencies. The average frequencies of all the species combined and the grass cover of the slip face topographical position are respectively 4.58 and 4.63 times greater than the deflation face topographical position and the top face topographical position. Therefore a result, the bare soil rate is 100% on the deflation face topographical position, 99.9% on the top face topographical position and 99.6% on the slip face topographical position