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Article Excerpt
ABSTRACT--Insects were sampled using pitfall traps during a two-year study in four mixed hardwood forest sites (cove, slope, open, and tornado-damaged) to determine their diversity beneath three dominant tree species: white oak, Quercus alba L.; sugar maple, Acer saccharum Marsh; and tulip poplar, Liriodendvon tulipi/era L. From pitfall traps, 191 species were identified representing 69 families in 15 orders. Significantly greater numbers of insects were collected in the cove site than in the slope or tornado-damaged sites. Also, species diversity and evenness were significantly greater in the cove site. Beetles represented 65% of the species identified at the four sites. Beetle diversity and richness did not differ significantly among the four sites, although species evenness was significantly lower in the tornado-damaged site.
The natural beauty and biodiversity of southern Appalachian forests attract more than 14 million people to the region annually. As a result, tourism contributes over 12 billion dollars per year to Tennessee's economy (Travel Industry Association, 2006). The Great Smoky Mountains National Park attracts more than nine million visitors annually who contribute to the local economy. The southern Appalachian economy relies heavily on the resulting public service, retail sales, outdoor recreation and forestry practices generated (Travel Industry Association, 2006). About 87% of Tennessee forests are comprised of hardwoods, making Tennessee one of the nation's leading hardwood lumber manufacturers. Employment and income in the region have remained stable over the last 20 years due in large part to the tourism and wood products industries (Travel Industry Association, 2006; Southern Appalachian Man and Biosphere Cooperative, 1996) which annually create more than 225,000 jobs.
The Appalachian mountains of eastern Tennessee support a diverse array of flora and fauna and many species are unique to these forest ecosystems (Buck et al., 2005). These species contribute to the overall forest stability and health. Invasion and establishment of exotic pests are considered one of the primary causes for disruption of habitats, posing significant threats to native insect species and the forests in which they occur. For example, population outbreaks of the gypsy moth, Lymantria dispar (L.), have caused defoliation of millions of hectares of forests, resulting in millions of dollars of damage (Ghent, 1994; Grace, 1986). Since its introduction into the United States, the gypsy moth has become established in most of the northeastern and midwestern states and the District of Columbia (USDA, 1996). The movement of the gypsy moth front, currently located near Roanoke, Virginia, has been reduced from 10.9 to 4.8 km per year by the "Slow the Spread Program". This slower movement has delayed the predicted time this pest will significantly impact forests in eastern Tennessee (Sharov et al., 2002). However, isolated infestations have been reported in the Great Smoky Mountains National Park, as well as in 71 counties in Tennessee (Strohmeier, 2006).
The gypsy moth is capable of repeated defoliation of trees over vast regions, resulting in major changes in flora, fauna and leaf litter composition, the quality of streams and rivers draining affected marshlands, and food availability for species residing in forest habitats. Understanding the ground-dwelling insect species composition of this hardwood forest may help to determine the impact of the gypsy moth, once established, on the insect composition and on the health of native southern Appalachian hardwood forests in eastern Tennessee. To date, no comprehensive study on the diversity of ground-dwelling insects in hardwood forests in eastern Tennessee has been conducted. Insect data collected prior to the anticipated gypsy moth invasion will be useful to assess the impact of the gypsy moth on native species inhabiting southern Appalachian hardwood forests. Such information also may be useful in identifying potential natural enemies of this exotic pest and provide a better understanding of the importance of species composition, seasonality, abundance, and diversity in southern Appalachian forest habitats. Over the past two decades, several exotic pests, such as the balsam woolly adelgid, Adelges piceae (Rathzeburg), beech scale, Cryptococcus fagisuga Lind., elongate hemlock scale, Fiorinia externa Ferris, and hemlock woolly adelgid, Adelges isugae (Annand), have become established in Tennessee and have the potential to dramatically change the composition of the fauna and flora within the area (Hughes, 1993; Lambdin et al., 2005; Vance, 1995)....
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