Hunter-Gatherer Population Expansion and Intensification: Malthusian and Boserupian Dynamics

Despite years of debate, the factors that control the long-term carrying capacity of human populations are not well understood. In this paper, we assess the effect of changes in resource extraction and climate-driven changes in ecosystem productivity on the carrying capacity of hunter-gatherer populations in a terrestrial and coastal ecosystem. To make this assessment, we build time-series estimates of changes in resource extraction using stable isotopes and ecosystem productivity using paleoclimate models and geomorphic records of flood events. These estimates of resource extraction and ecosystem productivity allow us to assess a complex model of population expansion that proposes linked changes between population density, resource extraction, and intensification. We find that changes in resource extraction had a larger effect on carrying capacity in both the terrestrial and coastal ecosystems than climate drivers of ecosystem productivity. Our results are consistent with the idea that both Malthusian limits on resources and Boserupian pressures to reorganize economic systems operate in hunter-gatherer populations over the long term. Our data and analysis contribute to evaluating complex models of population growth and subsistence change across archaeological cases.