Crop diversity is pivotal for the 33 millions of small farms that produce most of Africa's food, being the main option for smallholders to deal with limited resources and to cope with a changing environment. Small farms access to crop diversity relies on complex seed supply networks involving multiples actors and sources of diversity, such as other farmers, local markets, NGOs, farmers' organizations, research institutes, or private companies. Regulatory frameworks for access, use and conservation of both seed and plant genetic resources do not recognize the complexity of these seed supply networks, which affects farmers' ability to mobilize crop diversity needed for production and innovation. This opposition between the formal market-oriented seed system and the informal farmer-oriented system is largely documented, while the interaction and intertwining between the different components of seed supply networks and their consequences on crop diversity on-farm have attracted much less attention. This study conducted in the context of CoEx project thus aims at documenting crop diversity management practices in West-African agricultures. It combines largescale analysis in four west-african countries to get a picture of the state of crop diversity management at the regional scale, with in-depth analysis at the local scale in four sites in Senegal and Burkina-Faso to get insights into the mechanisms involved. This study focuses on the interplay between: i.diversity in crop species and varieties cultivated on-farm, ii.their functions in farmers' livelihoods, and iii.the diversity in seed sourcing and actors involved. Recent statistical network analysis methods will be used to disentangle the relations between these components.Through an interdisciplinary approach at the interface between agroecology and social sciences, this study ambitions to document the gap between the diversity of farmers' crop diversity management practices and regulatory frameworks and policies, and