Adam Lampert at the 105th ESA meeting:
Should multiple agents work together or split their job to control populations of harmful species?
The management of harmful species, including invasive species, pests, parasites, and diseases, is a major, global challenge. Harmful species cause severe damage to ecosystems, biodiversity, agriculture, and human health. The control of harmful species is challenging and often requires cooperation among multiple agents, such as land‐owners, agencies, and countries. Agents may have incentives to contribute less, leaving more work for other agents, which can result in inefficient treatment. A major question is, therefore, how should the agent allocate the job? Should they work together in the same area? Or should they allocate their responsibilities such that each agent would work only in its own designated area? We consider a dynamic game theoretic model, in which a Nash equilibrium corresponds to a possible solution. In turn, the policy (or the allocation) may determine the possible equilibria, which allow us to compare the outcome of various policies.

Our first result shows that, when the agents and the designated areas are identical, it is better that the agents work in distinct areas if the cost of damages from the harmful species is high; however, it is better for the agents to work together in the same area if that cost is lower. Our second result shows that, when eradicating a species, it is generally better if each agent work in the area from which he/she incurs more damages from the species; however, when the aim is to control the species at a certain level, it is generally better if the agents work together in all the areas simultaneously. Furthermore, in some cases, a better outcome can be achieved if the agents switch their roles during certain periods, such that each agent work in the area designated to her/his neighbor. This implies that the coordination among agents plays a critical role in the success of eradication and control of harmful species.