Abstract Analyzing how humans interacted with (and within) their greater ecosystems facilitates a more nuanced understanding of past lifeways. In this aim, we use food web modeling to reconstruct the biotic environment of Ancestral Pueblo people living in the central Mesa Verde region between A.D. 750 and A.D. 1300. This framework enables an investigation into the effects of species introductions and removals by linking humans to the species they consumed. We combine a diachronic examination of multiple archaeological assemblages with a database of every modern non-invasive species and their feeding links in a 4,600 square kilometer area of southwestern Colorado. Although human omnivory provided some flexibility, high population density likely curtailed the ability to prey switch. Ultimately, these factors combined to decrease the resilience of Ancestral Pueblo people to environmental changes.