This thesis presents the results of paleoethnobotanical investigations conducted at nine karst sites associated with the Maya site of Pacbitun in western Belize. The archaeobotanical remains were deposited during the Late Classic period and the site was abandoned at some point during this same time (c. A.D. 900). Paleoenvironmental data from the Maya Lowlands indicates that human activity contributed to regional climate change during the Late/Terminal Classic period. However, site-specific research has demonstrated a variety of responses to these social and ecological changes. The archaeobotanical data from this study is used as a proxy for understanding how people at Pacbitun ritually responded to macro-regional environmental stress. Ritual plant use at the cave sites does not conform to behavioral ecology models that predict biological, cost-fitness related responses to resource scarcity. Instead, the data supports a model of behavior based on culturally motivated ritual practices.