The starting point of this paper is a critique of the conventional view acording to which rapid population growth combined with widespread rural povevty in contemporary Africa necessarily leads to environmental degradation. After a brief discussion of the basic linkages underlying thu supposed nexus, the analysis of four regionol cases shows the diversity and the complexity of the current changes affecting african agricultures. These changes are shaped by the various interactions between natural endowments, structural, macro-economic conditions and the social, W institutional dynamics affecting producers strategies at the individual and community level. Among the economis factors, the increasing demand for food from growing urban populations is an important factor encouraging agricultural investment and Innovation which is conducive, in certain conditions, to agricultural Intensification and improved management of natural resources. Among the most significant social conditions, one can identify the role of tenure institutions and the social capital that allows a local society to adapt more quickly to new opportunities rising markets, e.g.) and to blend effectively endogenous values extemally generated informations and technologies. The diversity of the evolutions observed in four regional case studies (in Burkina Faso, Ivory Coast, Kenya and Nigeria) shows that there is no such thing as a fatal attraction leading from rapid population growth to environmental degradation. in order to better understand the complex causalities between these factors, several methodological guidelines are proposed; consider the diversity of cases (because only local and in-depth case studies allow to grasp the complex web of interacting factors), consider the diversity of scales (spatial and time-scales) In which the rationale of different causal processes can become apparent and intelligible, consider the diversity of agricultural and economic stragies by which various social groups, with different resouce endowments, try to cope with scarcity and to improve their livehoods.