Beyond the lamppost: Optimal prevention and control of the Brown Tree Snake in Hawaii

We develop an integrated model for the prevention and control of an invasive species. The generality of the model allows its use for both existing and potential threats to the system of interest. The deterministic nature of arrivals in the model enables clear examination of the tradeoffs inherent when choosing between prevention and control strategies. We illuminate how optimal expenditure paths change in response to various biological and economic parameters for the case of the Brown Tree Snake in Hawaii. Results suggest that it is more advantageous to spend money finding the small population of snakes as they occur than attempting to prevent all future introductions. Like the drunk that looks for his keys only where the light is, public policy may fail to look “beyond the lamppost” for snakes that have already arrived but have not yet been detected. Actively searching for a potential population of snakes rather than waiting for an accidental discovery may save Hawaii tens to hundreds of millions of dollars in future damages, interdiction expenditures, and control costs.