This paper presents a dynamic principal-agent model of aquatic species invasions in which a manager, concerned about the spread of invasive species across lakes by boaters, sets interseasonal management controls on a lake-by-lake basis, and boaters make a series of intraseasonal trip decisions to maximize random utility during the course of the season, conditional on the controls imposed by the manager. The results of a simulated invasion of Eurasian watermilfoil (Myriophyllum spicatum) highlight interesting aspects of the optimal management policies under two different management objectives: maximizing boater welfare and minimizing milfoil spread.

Off-highway vehicle (OHV) use is a rapidly growing outdoor activity that results in a host of environmental and management problems. Federal agencies have been directed to develop travel management plans to improve recreation experiences, reduce social conflicts, and diminish environmental impacts of OHVs. We examine the effect of land access restrictions on the welfare of OHV enthusiasts in Utah using Murdock's unobserved heterogeneity random utility model (Murdock 2006). Our models indicate that changing access to public lands from fully “open” to “limited” results in relatively small welfare losses, but that prohibiting access results in much larger welfare losses.

Two benefit-transfer approaches are used to estimate welfare losses from closure of Lake Erie beaches. We identify conditions for which the function transfer, which is more time-consuming and data-intensive, is worth the effort relative to a simple value transfer. The function transfer was essential for estimating beach demand (trips) and demand elasticity (change in trips); when evaluating individual beach closures with known trip demand, the two methods yielded similar results. Results produced by the two transfer methods deviated (up to 106 percent) when multiple beaches were closed simultaneously because value transfer did not account for the loss of beach substitutes.