Studies identified desertification and land degradation as a possible cause for persistent drought in the Sahel. The specific vegetation dynamics in the Sahel are good indicators for this kind of environmental change. Due to the scattered availability of ground truth data in huge parts of the Sahel, EO data might provide the only reliable means for sound analysis and detection of long-term changes. This study focuses on vegetation dynamic monitoring over the Iullemeden Aquifer (SAI) using ENVISAT MERIS data. The biophysical vegetation variables fAPAR and NDVI were analysed in terms of the vegetation changes within one growth period. It turned out that these informations are important indicators to make reliable statements on ecological changes. Considering that in future similar products are available, it’s an outstanding tool to monitor the whole Sahel zone with a high temporal resolution to analyse vegetation dynamics in terms of climate change and human impact.