2006 journal article

Landscape-scale prediction of hemlock woolly adelgid, Adelges tsugae (Homoptera : Adelgidae), infestation in the southern Appalachian Mountains

ENVIRONMENTAL ENTOMOLOGY, 35(5), 1313–1323.

co-author countries: United States of America 🇺🇸
author keywords: hemlock woolly adelgid; southern Appalachians; dispersal; prediction; landscape connectivity
Source: Web Of Science
Added: August 6, 2018

After causing substantial mortality in the northeastern and mid-Atlantic United States, the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), has recently invaded the southern Appalachian region. Although general estimates of regional spread exist, the landscape- level dynamics of A. tsugae invasion are poorly understoodNparticularly factors predicting where the pest is likely to Þrst infest a landscape. We examined Þrst-year infestation locations from Great Smoky Mountains National Park and the Blue Ridge Parkway to identify possible factors. For 84 infested and 67 uninfested sites, we calculated values for a suite of variables using a geographic information system. After identifying signiÞcant variables, we applied four statistical techniquesN discriminant analysis, k-nearest neighbor analysis, logistic regression, and decision treesNto derive classiÞcation functions separating the infested and uninfested groups. We used the resulting functions to generate maps of A. tsugae infestation risk in the Great Smoky Mountains. Three proximity variables (distance to the closest stream, trail, and road) appeared in all four classiÞcation functions, which performed well in terms of error rate. Discriminant analysis was the most accurate and efÞcient technique, but logistic regression best balanced accuracy, efÞciency, and ease of use. Our results suggest that roads, major trails, and riparian corridors provide connectivity enabling long-distance dispersal of A. tsugae, probably by humans or birds. The derived classiÞcation functions can yield A. tsugae infestation risk maps for elsewhere in the southern Appalachian region, allowing forest managers to better target control efforts.