The LTVTP project incorporates model analysis using a variety of dynamical systems and numerical techniques.The project moves iteratively between archaeological analysis and mathematical modeling in several ways. Patterns observed in the cases will inform the modeling and in turn, we assess whether effects predicted by the modeling play out as expected in our case studies and how the case studies fit within the modeling outcomes.

For example, Anderies (2006) has used a simple model of Hohokam subsistence to investigate how irrigation infrastructure and associated social institutions may provide robustness to frequent, small deviations in precipitation. However, the successful mitigation of frequent, small deviations in precipitation may have also increased the vulnerability of the system to large, rare climatic shocks. Reference:Anderies, J.M. (2006) Robustness, institutions, and large-scale change in socio-ecological systems: The Hohokam of the Phoenix Basin. Journal of Institutional Economics, 2, 133-155.

Nelson et al. (2010) have built on the basic insight articulated by Anderies (2006) to motivate a comparison of social and physical water control infrastructure across three archaeological case studies in the American southwest. In general, there is an apparent inverse relationship between the severity of social-ecological transformation in an archaeological case study and the size and complexity of water control infrastructure. The lesson is that the resilience of social-ecological systems is intimately tied to investments made in social infrastructure. Reference:Nelson, Margaret C., Keith Kintigh, David R. Abbott, and John M. Anderies. (2010) The Cross-scale Interplay between Social and Biophysical Context and the Vulnerability of Irrigation-dependent Societies: Archaeology's Longterm Perspective. Ecology and Society, 15, 33.

Anderies et al. (2008) have also used modeling to explore the costs of crop response diversity in an agroecological system. This study was motivated by the la Quemada archaeological case study. Anderies et al. (2008) find that farmers only benefit from growing two crops with different responses to drought in a precipitation regime "sweet spot." If rainfall is too consistent and high, diversity makes no difference for a farmer because both crops never fail. If rainfall falls below critical production levels too frequently, then crop response diversity does not help a farmer because both crops fail simultaneously. However, if rainfall falls below critical production levels with a moderate frequency, then crop response diversity can help a farmer consistently produce a targeted level of food. Reference: Anderies, John M., Ben A. Nelson and Ann P. Kinzig. (2008) Analyzing the Impact of Agave Cultivation on Famine Risk in Arid Pre-Hispanic Northern Mexico. Human Ecology, 36, 409-422.

Several other models developed by researchers affiliated with the LTVT project are also avaiable through the OpenABM Consorium. The following links include model documentation and source codes. Please also see our publications.

Household Food Sharing

Population Aggregation in Arid Environments



Scheme of the main processes in the Hohokam subsistence model by John M. Anderies