The Evolving Role of Forest Inventory and Analysis Data in Invasive Insect Research

Enabled by humans’ ever-expanding trade and travel networks, invasive alien species are crossing borders worldwide at alarming rates ( Haack 2006 ; Haack and Rabaglia 2013 ; Hulme 2009 ; Kaluza et al. 2010 ; Koch et al. 2011 ; Liebhold et al. 2006 ; Lodge et al. 2006 ; Perrings et al. 2005 ; Pyšek and Richardson 2010 ; Tatem 2009 ; Westphal et al. 2008 ). An astonishing 50,000 + non-native species have been introduced into the U.S. either accidentally or purposefully, and approximately 4,500 of those introductions have been arthropods ( Pimentel et al. 2005 ). Furthermore, new establishments of non-native species (arthropods and others) continue to accumulate rapidly, at an average of six per year in California and 15 per year in both Hawaii and Florida ( Center for Invasive Species Research 2014 ). In the mid-1990s, it was estimated that some 360 introduced insect species had become established in U.S. forests ( Liebhold et al. 1995 ; reviewed by Moser et al. 2009 ). According to one estimate, about 30% of those introduced species have since become major forest pests ( Pimentel et al. 2005 ). In a more recent study, Aukema et al. (2010) generated a list of 455 non-indigenous forest pests that had become established in the U.S. as of 2006. A few examples of high-impact forest insect pests include the beech scale [ Cryptococcus fagisuga Lindinger (Hemiptera: Eriococcidae)], which is associated with beech bark disease; the European gypsy moth [ Lymantria dispar Linnaeus (Lepidoptera: Erebidae)], which feeds on hundreds of plant species, especially oak and aspen; the hemlock woolly adelgid [ Adelges tsugae Annand (Hemiptera: Adelgidae); HWA], which attacks all age classes of both eastern hemlock [ Tsuga canadensis (L.)] and Carolina hemlock ( Tsuga caroliniana Engelm); and the balsam woolly adelgid [ Adelges piceae (Ratz.) (Hemiptera: Adelgidae); BWA], which kills firs ( Abies sp.), and in particular, has virtually eliminated mature firs in Great Smoky Mountains National Park. Introduced to North America between 1890 and 1954, these four insects are now widespread in the eastern U.S. Newer threats include the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), which is believed to have arrived in the Detroit, Michigan, area during or even before the 1990s ( Siegert et al. 2014 ), and the redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae), the vector of laurel wilt disease, which was first detected near Savannah, Georgia, in 2002 ( Koch and Smith 2008 ). Like the previous examples, these two species are certain to dramatically alter the composition of landscapes where their hosts occur.