Correlations between farmer ethnic identity and the agrobiodiversity they maintain have been identified globally. This has been maintained even as small-scale farmers are increasingly connected to extra-local political economic systems, which are cited as the driver of global agrobiodiversity erosion. Yet, how ethnicity influences the maintenance of biodiverse farming systems is poorly understood. Employing a political ecology framework that integrated qualitative, demographic, and agroecological methods in Caribbean Nicaragua's Pearl Lagoon Basin, this research revealed patterns indicating that farmers who identify with the area's indigenous (Miskito) and afro-descendant (Creole and Garífuna) 'minority' groups tend to maintain more diverse farms than nearby farmers who identify as mestizo, particularly those who are recent migrants to the region. In contrast to previous studies, however, the most connected farmers in the Basin tend to have the highest levels of agrobiodiversity within their farming systems. Qualitative and regression analyses reveal that ethnic patterns in the maintenance of agrobiodiversity are explained in part by the historical farming practices that characterize land use in the Basin and the agroecological knowledge that farmers develop over a lifetime farming in this socio-ecological context. Further, by acknowledging the plastic nature of ethnic identity, this research highlights the importance of ethnic-based land rights in the Nicaragua's South Caribbean Coast Autonomous Region as a critical factor that directly and indirectly influences the ethnic identities of farmers in the Pearl Lagoon Basin and their abilities to participate in agricultural development projects whose extension activities promote agrobiodiversity conservation.Key Words: Agrobiodiversity, ethnicity, land use and land use change, development, Nicaragua, Pearl Lagoon Basin