From the household to the community : a resource demand and land-use model of indigenous production in Western Amazonia

This study takes a spatial perspective to analyze traditional land-use and production systems in humid tropical environments, with emphasis on the agricultural dimension. The setting is the Pastaza River Basin in the Ecuadorian Amazon and the Achuar and Shiwiar indigenous groups are used to highlight the elements of these systems. This dissertation relies on land use/land cover change and agricultural change theories to analyze indigenous land use systems. The study uses empirical data to examine the linkages between decision making, the demand for land resources, and landscape change. Results suggest that the transition from nomadic-dispersed to permanent-nucleic villages leads to the implementation of a land-use zoning system that responds to changes in resource availability. This system can be represented by a concentric land-use-zones model that depicts an efficient distribution of land resources around service infrastructure such as landing strips, health centers, or schools. Overall, the demand for land resources varies with changes in household composition. At the beginning of the household’s life cycle, the demand for farmed land is relatively low because the family’s food requirements are minimal. As households grow, the demand increases and agriculture expands. As young adults leave the house for any reason, the demand for cultivated land decreases and the extent of agricultural land use contracts. In addition, the demand for land resources is associated with ecological conditions of the habitats in which production occurs and with distance to the community. Areas with good soils have smaller agricultural plots than areas with poor soils. People living in poor-soil environments manage larger fields but produce less food per unit of area than households with good soils. The probability of an area of becoming agriculture increases in sites farther away from existing cultivation fields, service infrastructure, and homes since areas closer to these features have already been used and are recuperating as fallows. Additionally, people are cultivating in areas that are relatively steeper than older agricultural fields. These findings suggest that indigenous people are expanding agriculture into areas with adverse pedologic and topographic conditions, which may be an indication of overall scarcity of land resources for food production.