To reverse the trend of massive degradation of vegetation cover and decline in land productivity in Sahelian regions, important programs aimed at promoting both the revegetalization and rehabilitation of degraded ecosystems have been implemented but, with mitigated results owing, in some cases, to drastic environmental conditions. Due to recent advances in our knowledge in plant and soil biology and ecology, relevant progress has been achieved during reforestation, for instance, with 'biologically improved plants' (i.e. controlled mycorrhized plants). Besides their beneficial effects on seedlings' early survival and future development, which is profitable both in ecological and economic terms, the mycorrhizal symbiosis could also result in ecological imprints in soil functioning and in plant community dynamics. In this chapter, we will present and discuss some of the relevant research work that has been implemented in Sahelian ecosystems with an emphasis on studies that have dealt with various monitoring and/or management strategies of the Mycorrhizal Soil Infectivity to sustain the recovery of the vegetation in stressed conditions.