Conservation of Agro-biodiversity in Baja California Oases

Agro-biodiversity in the desert oases of Baja California, Mexico is a product of isolation and integration through time and across the various spaces of the peninsula. The oases hold heirloom perennial crop species first introduced by Jesuit missionaries (1697-1768) and represent geographies of historical dissemination. I selected fifteen Jesuit mission oases and surveyed the oasis gardens for species richness and abundance. To understand the cultural, political and economic forces that create these patterns of persistence within the oases, I conducted interviews on farming system practices, geographical remoteness, market integration, land tenure, tourism, protected area status and cultural practices. In all, I surveyed 241 gardens and documented eighty-nine total perennial crop species. Historical records in 1774 describe twenty-one perennial crop species in cultivation after the Jesuit expulsion. I calculated species-area relationships and rank-abundance for total perennial and mission crop species in each oasis and inventory comparisons for those oases with quantitative historical data to analyze retention of historic mission species. A high persistence of mission species indicates that oases serve as agro-biodiversity refugia, or protected source areas for agricultural species. These mission-oases act as a network of interconnected sites that are also isolated from one another and the Mexican mainland by the rugged environment, limited transportation infrastructure, and by sea. Within the network, these fifteen oases span a range of small and hours distant from the nearest resource center, to fully urbanized with international ports and airports. I describe how phases and processes of isolation and connectivity shape and transform the agro-biodiversity profiles in this archipelago of peninsula oases