Our research addresses the gap in ecological research on the diversity levels, fine-grain patterns, and social-ecological interactions of high-diversity agroecosystems in tropical mountains. The research site of the Arbieto-Tarata landscape is a globally significant hotspot of the agrobiodiversity of maize occurring at mid-elevations (2000-3000 masl) in the Bolivian highlands. Our research predicts spatial spillover and edge-effect processes of combined social and ecological factors leading to medium-high levels of agrobiodiversity and the clustering of same-crop fields. These factors include local social-ecological interactions and the drivers and feedbacks of global telecoupling that includes labor market integration and partial migration among smallholder land-users. Field-level diversity was estimated through the sampling of 350 maize fields in 2012. Identification and analysis of the spatial clustering of high-agrobiodiversity fields and other crops types was estimated using high-resolution remotely sensed QuickBird and GeoEye images tasked in 2006 and 2012. A methodology was designed to sequence field-type identification and the application of join-count statistical analysis and model-testing in order to determine the spatial clustering of high-agrobiodiversity maize fields and other land use.
Results/Conclusions
The Arbieto-Tarata landscape was found to contain nearly 8,000 smallholder-cultivated fields at 2500-2800 masl. Drivers of global changes, particularly high levels of migration, demonstrated ecological telecoupling with the agroecosystems and agrobiodiversity dynamics of smallholder populations. Per-area richness of the variety-level diversity of Andean maize ranged from 1.35-1.43 at the study site. Results showed the occurrence of 10 maize races. This total represents 31% of landrace-level maize diversity in Bolivia and 3% of the Western Hemisphere. These findings demonstrate the combination of changes and continuity in this global agrobiodiversity hotspot of maize. Mechanisms important to agrobiodiversity conservation includef significant levels of the predicted clustering of fields between 2006 and 2012. The degree of this clustering is found to differ among local geographic and environmental sub-areas within the landscape reflecting fine-grain variation of locally specific causal linkages. Extra-local causal linkages include high levels of migration, water-resource shortages, and urbanization. Mechanisms involved the informal and formal coordination associated with the spatial clustering of same-crop fields. It improves the efficiency of resource allocations and lowers overall costs of production and enables the viability of high-agrobiodiversity Andean maize in smallholder land use and agri-food systems amid global changes. This paper discusses the broader policy and scientific implications of these findings including scaling up, support of the social-ecological resilience of agrobiodiversity globally, and the ecological concept of human-environment telecoupling.