Mapping host-species abundance of three major exotic forest pests

Abstract

Periodically over the last century, forests of the Eastern United States have been devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gypsy moth. The distributions of host species of these alien pests were mapped in 1-km 2 cells by interpolating host basal area/ha from 93,611 forest-inventory plots in 37 states. The interpolated surfaces were adjusted for forest density (percent land cover) by multiplying values by an estimate of percent forest cover derived from existing land-cover maps (30-m 2 cells). According to our estimates, BBD currently occupies only about 27 percent of its potential range in land area, but has invaded more than 54 percent in total host density. HWA occupies nearly 26 percent of its potential range in land area, and about one-quarter in total host density. Gypsy moth occupies only 23 percent of its potential range in the Eastern United States, and only 26 percent in total host density. Headquarters of the Northeastern Research Station is inNewtown Square, Pennsylvania. Field laboratories are maintained at: Amherst, Massachusetts, in cooperation with the University of Massachusetts Burlington, Vermont, in cooperation with the University of Vermont Delaware, Ohio Durham, New Hampshire, in cooperation with the University of New Hampshire Hamden, Connecticut, in cooperation with

Management of invasive Allee species

“…This region is characterized by small and sparse forest patches of preferred hosts for gypsy moth (Morin et al, 2005). This is consistent with previous research that found gypsy moth with Allee effects have a critical patch size, below which a population cannot persist (Verken, Kramer, Tobin, & Drake, 2011).…”

Replacement of a dominant viral pathogen by a fungal pathogen does not alter the collapse of a regional forest insect outbreak

“…Biological variables included (1) whether or not the site was within an area in which gypsy moth defoliation (as determined through aerial detection surveys; USDA Forest Service 2013a, b) occurred at least once during the 5 years prior to the study (2004)(2005)(2006)(2007)(2008), (2) the gypsy moth egg mass density prior to egg hatch in 2009, and (3) the basal area of the gypsy moth's preferred host tree species at each site, according to Morin et al (2005); preferred host tree species include those in the genera Quercus, Betula, Crataegus, Populus, Salix, and Tilia (Liebhold et al 1995). The average maximum and minimum monthly temperatures (March-June 2009) and monthly precipitation (March-June 2009) for each site were obtained from the PRISM Climate Group, Oregon State University (2011).…”

Spatial analysis of harmonic oscillation of gypsy moth outbreak intensity

“…Host abundance was measured as the basal area per hectare of host tree species that are preferred hosts . This raster GIS layer was developed by interpolating host basal area from [90,000 forest inventory plots (Kingsley 1985) and then adjusting for forest density by multiplying interpolated host basal area by percentage forest cover (Morin et al 2004). Seventy-nine tree species in eastern North America are considered to be preferred hosts, but oaks (Quercus spp.)…”

“…Host tree abundance was based upon a 1 km raster GIS layer developed by Morin et al (2004). Host abundance was measured as the basal area per hectare of host tree species that are preferred hosts .…”