Nuisance or not? Tourism impacts from spongy moth tree defoliation in U.S. National Park Units

Abstract

Non-native and native invasive defoliators can decrease recreation visitor enjoyment. We use data on observed recreation visitation to investigate the impact of spongy moth, Lymantria dispar L. (Lepidopetra: Erebidae) outbreak events. Spongy moth is a polyphagous defoliator pest that emerges in the early spring and feeds through the summer months. Caterpillar feeding can completely defoliate trees during outbreaks, sometimes resulting in tree mortality. We gathered data on defoliation events in U.S. National Parks and estimated a fixed effects regression model with lags to estimate the dynamic impact of outbreak events. We found that there is a decrease in visitation in the year of the outbreak infestation, with statistically significant effects up to five years after the event. Future analyses could differentiate between the infestation event itself and the management actions, such as chemical or biological treatments, taken to control outbreaks.

Citation

Bruck, Sonia R.; Sloggy, Matthew R.; Coleman, Tom W.; Thompson, Michelle J. 2026. Nuisance or not? Tourism impacts from spongy moth tree defoliation in U.S. National Park Units. Journal of Environmental Economics and Policy: 1-18. https://doi.org/10.1080/21606544.2026.2696373.