||Recent interest in the Basketmaker-to-Pueblo (or Full Formative) transition on the Colorado Plateau indicates the need for better characterization of the subsistence strategies of the Basketmaker II period (500 BC-500 AD). While the human stable isotope record for this period is extensive, regional resource isotope data are less robust, inhibiting formal modeling. This dissertation presents new carbon and nitrogen isotope data for modern flora, the results of roasting experiments on banana yucca tissues, archaeofauna, and maize specimens from Cedar Mesa, Utah. Ecological patterning is not seen at the chosen scale of analysis; δ13C does not correlate with elevation gradients and δ15N does not correlate with visual assessments of cryptobiotic crust development. However, relative to other regions in the Intermountain West, Cedar Mesa flora and fauna (and previously published human values) show significant depletion in Nitrogen 15, suggesting that the fixation of atmospheric nitrogen by cryptobiotic crusts sets a unique δ15N baseline for local food-webs-potentially biasing formal modeling. Mixing models calculated using the Bayesian mixSIAR framework show strong correlations between feasible source proportions. Such correlation permits extrinsic linear constraints and a posteriori aggregation of resource proportions to substantially narrow diet model outcomes, and suggest that Cedar Mesa Basketmaker II diets were comprised of between 70 and 90% maize.