Unstable Ecological-Economic Equilibria: The Effects of Invasive Species and Ecosystem Restoration on Nutrient Management Compromise in Lake Erie
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EmailTogether, lake ecosystems and local human activity form complex ecological-economic systems characterized by feedback loops and discontinuous change. Researchers in diverse fields have suggested that complex systems do not have single stable equilibr...
Together, lake ecosystems and local human activity form complex ecological-economic systems characterized by feedback loops and discontinuous change. Researchers in diverse fields have suggested that complex systems do not have single stable equilibria in the long-term due to inevitable perturbation. During this study, we sought to address the general question of whether or not stable ecological-economic equilibria exist in highly stressed and managed lacustrine systems. Using an integrated human-biophysical model, we investigated the impacts of a species invasion and ecosystem restoration on ecological-economic system equilibrium, defined here as a compromise in phosphorus (P) management between opposing stakeholders, in western Lake Erie. Our integrated model is comprised of a calibrated ecological sub-model representing Sandusky Bay and a P management sub-model that reflects the societal benefits and costs of P regulation. These two sub-models together form a dynamic feedback loop including freshwater ecology, ecosystem services, and P management. We found that the invasion of dreissenid mussels decreased ecosystem resistance to eutrophication, necessitating increased P management to preserve ecosystem services and thus creating the potential for multiple unstable ecological-economic equilibria. Additionally, our results suggest that net benefits in the region following the invasion of dreissenids may never again reach the pre-invasion level if on-site P control is the sole management lever. Further demonstrating system instability, large-scale wetland restoration shifted points of management compromise to states characterized by less on-site P management and higher environmental quality, resulting in a significant increase in net benefits in the region. We conclude that lacustrine ecological-economic systems are open and dynamic and we recommend that future models of these systems emphasize site-specific perturbation over equilibrium, thereby aiding the development of management plans for building system resistance that are both flexible and sustainable in an unknowable future.
Investigator(s)
Lead Investigator(s):
Eric Roy
