Socio-agronomic features define the structure of socioecological seed network exchanges and “on farm” conservation of agrobiodiversity in traditional communities

Background Traditional agricultural systems are rooted in the local management, selection, and conservation of agrobiodiversity. Understanding the socioecological dynamics that sustain these systems is essential for developing sustainable practices that ensure food security and sovereignty in the territories of traditional and Indigenous peoples. This study examines the role of seed exchange networks in on-farm agrobiodiversity conservation in Quilombola communities that live in environmental and political threats. We emphasize the role of socioecological networks and socio-agronomic variables in shaping how agrobiodiversity is maintained, shared, and regenerated across time and space. Methods We conducted semi-structured interviews, free listing, participant observation, and guided tours with 48 agrobiodiversity management units (AMUs) in five communities, documenting socio-agronomic variables and ethnovariety richness, with botanical identification in the field and literature. From the 359 ethnovarieties recorded, 15 were randomly selected for detailed seed exchange network analysis. The complete network of 185 AMUs (48 internal, 137 external) and 424 exchanges was analyzed using negative binomial GLMs for richness (H1), PCA and Poisson GLMs for centrality metrics (H2), and network metrics (degree, betweenness, harmonic closeness, modularity, connectivity, weighted nestedness) calculated in Gephi and R, compared against null models to assess conservation potential (H3). Results and Discussion The 48 AMUs managed an average of 40 ethnovarieties each. Agro-environmental diversity, cultivated area, and time in the community were positively associated with richness, which in turn increased AMU centrality, highlighting their role as agrobiodiversity guardians and network bridges. Despite high diversity, the seed exchange network displayed low nestedness and connectivity but high modularity, indicating cohesive subgroups with strong internal exchanges and limited intergroup seed flows. This pattern reflects both social cohesion and fragmentation, and reveals vulnerabilities, as varieties unevenly distributed across modules may not circulate widely, reducing resilience. Conclusions Historical and material conditions are critical to sustaining on-farm agrobiodiversity conservation in quilombola territories. Land tenure security and territorial rights are essential for maintaining traditional agroecosystems that integrate ecological knowledge, cultural heritage, and biodiversity management. Strengthening seed exchange connectivity, fostering collaboration across groups, and protecting these territories are urgent actions to enhance resilience, safeguard traditional knowledge, and ensure long-term biocultural justice.