The sustainability of vegetation is closely linked to anthropogenic practices, climate, and investments in environmental management. The objective is to help prioritize the impacts of anthropogenic practices and rainfall on ecosystem evolution. Following the rainfall gradient, a diachronic analysis of Landsat images from November or December for the years 1986, 1999, 2013, and 2018 was carried out. These cloud-free satellite images from Landsat 7 to 8 bands were downloaded from the USGS website: http://www.earthexplorer.usgs.gov/. Processed according to supervised classification, a Pearson correlation matrix relating to land cover types (rock outcrop, irrigated crop, rain-fed crop, fallow land, water body, forest reserve, shrub savanna, shrub steppe) was established. The results show that anthropogenic practices influencing vegetation change are highly diverse.

In Niger, after the severe droughts of the 1970s and 1980s, several development projects promoting trees on farms and creating village woods were implemented. The objective of this study is to analyze the structure and diversity of stands of woody legumes (Faidherbia albida) in the department of Dogondoutchi which is a successful case of environmental policy, in order to serve as a reference for the orientation of future development works. The data were obtained on the one hand through a floristic inventory on a perpendicular transect following the four cardinal points on 60 plots of 2500 m², and on the other hand through individual surveys of 90 farmers. The results obtained show an overall specific richness of 19 species divided into 10 families in the study area. Mimosaceae (52%) are the families most encountered with Faidherbia albida (49%). The current dynamics of this Faidherbia albida stand is regressive because of the poor regeneration and aging of the subjects. Analysis of survey data shows that the regressive dynamics are due to parasitic pressure. Therefore, urgent measures must be taken by the state to eradicate this parasitic pressure.