Socio-agronomic features define the structure of socioecological seed exchange network and "on farm" conservation of agrobiodiversity in quilombola communities in Brazil.

backgroundTraditional 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 assessed the role of seed exchange networks in on-farm agrobiodiversity conservation in quilombola communities in Brazil that face 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.

methodsWe conducted semi-structured interviews, free listing, participant observation, and guided tours with 48 agrobiodiversity management units (AMUs) from five communities, documenting socio-agronomic variables and ethnovariety richness with botanical identification in the field and literature. We recorded all ethnovarieties shared among internal AMUS - living in the quilombola communities, and external AMUs - outside the territory. We then sorted 15 ethnovarieties per internal AMUs to collect data on seed exchange interactions. Further, we registered data on socio-agronomic variables, ethnovarieties richness, and seed flows (donation and reception) to analyse the properties of AMUs (nodes in the network) and seed exchange patterns in the network, and assess their potential for conserving agrobiodiversity. RESULTS AND DISCUSSION: We documented a total of 359 ethnovarieties. The complete and open network was formed by 185 AMUs - 48 internal and 137 external - which realized 424 events of seed exchanges. Agro-environmental diversity, cultivated area, and the period living in the community were positively associated with AMUs' richness and its centrality in the network, highlighting their role as agrobiodiversity guardians and network bridges. The seed exchange network displayed low nestedness, low connectance, and high modularity, indicating the formation of cohesive subgroups of AMUs with strong exchanges among specific partners and limited intergroup seed flows. These findings reflect social segregation and reveal vulnerabilities, as varieties unevenly distributed across modules may not circulate widely, reducing agrobiodiversity resilience.

conclusionsWe argue that historical and material conditions are critical for 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 - from inside and outside territories - are urgent actions to enhance resilience, safeguard traditional knowledge, and ensure long-term biocultural justice.