Input–output modeling, outdoor recreation, and the economic impacts of weeds

Nonindigenous invasive weed species can have substantial negative impacts on the quantity and quality of outdoor recreational activities such as fishing, hunting, hiking, wildlife viewing, and water-based recreation. Despite the significance of impacts on recreation, very little research has been performed to estimate the corresponding economic losses at spatial scales such as regions, states, and watersheds. This is true primarily because in most jurisdictions the data necessary to estimate recreational impacts are scarce and incomplete. Because of the challenges involved in measuring recreational losses precisely, we illustrate a method that can provide indications of the ranges in which the true economic losses likely lie. To reflect underlying uncertainty in parameters such as the number of acres infested in a jurisdiction and the rate at which wildlife-related recreation decreases as a function of increasing weed infestation, we developed a range of estimates using lower, medium, and higher scenario combinations of parameter and variable values. Our case study jurisdiction is a western state (Nevada) in which nonindigenous weed infestations on public lands have expanded rapidly in recent years. Under conservative assumptions, the negative economic impacts stemming from the adverse influence of nonindigenous weeds on wildlife-related recreation in Nevada likely range from $6 million to $12 million per year. Using the most conservative findings for annual recreation losses, the predicted discounted stream of negative economic impacts over a future time horizon of 5 yr ranges from about $30 million to $40 million in Nevada, depending on actual future expansion rates of weeds.