A spatial-dynamic value transfer model of economic losses from a biological invasion

Rigorous assessments of the economic impacts of introduced species at broad spatial scales are required to provide credible information to policy makers. We propose that economic models of aggregate damages induced by biological invasions need to link microeconomic analyses of site-specific economic damages with spatial-dynamic models of value change associated with invasion spread across the macro-scale landscape. Recognizing that economic impacts of biological invasions occur where biological processes intersect the economic landscape, we define the area of economic damage (AED) as the sum of all areas on the physical landscape that sustain economic damage from a biological invasion. By subsuming fine-scale spatial dynamics in the AED measure, temporal dynamics of the AED can be estimated from an empirical distribution of the AED effective range radius over time. This methodology is illustrated using the case of a non-native forest pest, the hemlock woolly adelgid (HWA; Adelges tsugae). Geographic Information Systems and spatially referenced data provide the basis for statistical estimation of a spatial-dynamic value transfer model which indicates that HWA is annually causing millions of dollars of economic losses for residential property owners in the eastern United States.