Dissertation Defense, Mark Stover, "A Computational Model of Social-Ecological Dynamics on Rapa Nui (Easter Island), AD 1500-1700"

Little is known about the dynamics of environmental stress as it moves through social-ecological systems. What causes it to accelerate or diminish as it travels through space and time, or across hierarchical levels of the systems it disrupts? Do structural properties in these systems play a role? Do these properties mitigate or amplify the effects of stress, and how do they in turn change as a result? Of particular interest to the research community working on sustainability in social-ecological systems are press-pulse dynamics, or the relationship between long-term environmental pressures such as land degradation, and short-term environmental pulses such as droughts or floods. The effects of these dynamics on social resilience, institutional capacity and civil conflict are increasingly of concern as climate change proceeds and resources diminish. The focus of this dissertation is the role of resource scarcity within systems under stress, particularly the sort of distributional scarcity of natural resources that is driven by social hierarchies. The dissertation reports on a multi-agent computational model of Rapa Nui’s social-ecological system during its two centuries of decline and ultimate collapse from AD 1500 – 1700. The model simulates environmental stresses of degradation and drought as they interact with dynamics of agent behavior, allowing the exploration of resource distribution as a structural property of the Rapa Nui system that may have influenced the collapse process.