Integrating the conservation of biodiversity by smallholder farmers with agricultural intensification is increasingly recognized as a leading priority of sustainability and food security amid global environmental and socioeconomic change. An international research project investigated the smallholder agrobiodiversity of maize (corn) in a global hotspot (Bolivia) undergoing significant intensification. Peach-based intensification was pronounced (300-400%) and prolonged (2000-2010) in study areas. Intensification and maize agrobiodiversity were found to co-occur within smallholder landscapes. Interactions of these field systems did not trigger land-change tipping points leading to landrace extirpation. By 2010 maize landraces in the study areas still demonstrated high levels of taxonomic and ecological biodiversity and contributed significantly to this crop's agrobiodiversity at national (31%) and hemispheric (3%) scales. Social and ecological resilience and in situ conservation of the maize agrobiodiversity by Bolivian smallholders was enabled through robust linkages to off-farm migration; resource access and asset capabilities among both traditional and nontraditional growers; landrace agroecology and food uses; and innovative knowledge and skills. The smallholders' resilience resulting from these linkages was integral to the conditional success of the in situ conservation of maize agrobiodiversity. Environment-development interactions both enabled smallholders' agrobiodiversity resilience and influenced the limits and vulnerability of agrobiodiversity. Scientific policy recommendations regarding land-use planning and sustainability analysis are targeted to specific Río+20 priorities for agrobiodiversity.