Agricultural Frontiers, Health Care, and Population Size Impact the Recovery Patterns of Brazilian Indigenous Nations

After centuries of decline, the populations of indigenous nations in Brazil began to increase in the 1970s. Population Ecology theory predicts that population size affects the dynamics of three basic recovery patterns: intra-specific cooperation (a positive effect of population size); competition (a negative effect); and exponential growth (no effect of population size). We analyzed the dynamics and recent history of 25 Brazilian indigenous populations using a cross-sectional approach to understand how exogenous and cultural variables (e.g., deforestation, diet richness) interact with population levels. We found that population size, access to health care, the extent of indigenous territories, and degree of deforestation impact the recovery of indigenous population levels.