We propose a model that may explain long-term population growth and decline events among human populations: The intensification of production generates a tradeoff between the adaptive capacity of individuals to generate a surplus of energy to maximize their fitness in the short-run and the long-term capacity of a population as a whole to experience a smooth transition into a demographic equilibrium. The model reconciles the conflicting insights of dynamic systems models of human population change, and we conduct a preliminary test of this model’s implications in Central Texas by developing time-series that estimate changes in human population density, modeled ecosystem productivity, human diet, and labor over the last 12,500 years. Our analysis indicates that Texas hunter-gatherers experienced three long-term population growth overshoots and recessions into quasi equilibria. Evidence indicates that each of these overshoots and recessions associate with changes in diet and labor devoted to processing high density, lower quality resources to unlock calories and nutrients. Over the long-term, population recessions may be necessary for populations to experiment with social and physical infrastructure changes that raise the carrying capacity of their environment.

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 via human stable isotopes and ecosystem productivity via 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.

In locales where much of the archaeological record has been destroyed or heavily impacted by pothunting and development, engaging with collector informants—including those who legally excavated sites on private property in the 1980s—can help fill crucial information gaps. However, such collaboration can pose ethical, and potentially legal, challenges. In this article, I outline research goals and results from a survey project in southeast Arizona's York-Duncan Valley, discuss the legal and ethical implications involved in working with former pothunters, and offer a critical evaluation of project practice. Finally, I offer a set of recommendations for those considering similar collaborations. I argue that the rejection of individuals who are knowledgeable about damaged or destroyed archaeological sites effectively silences the sites forever. Data acquired from former pothunters led to the identification and recording of 25 of 87 archaeological sites in the York-Duncan Valley. These individuals also served as interlocutors with others in the local community, helping us foster the trusted relationships necessary to promote site preservation on private property. A long-term engagement strategy that incorporates an assessment determining whether collector informants are responsible or responsive and that nurtures community involvement in preserving local archaeology offers a more productive course of action.