The Effect of the European Wild Boar, Sus scrofa, on Gray Beech Forest in the Great Smoky Mountains

Abstract

The European wild boar Sus scrofa L., an exotic species, entered the Great Smoky Mountains National Park during the 1940s. Because of their high reproductive potential and their adverse impact on the native flora and fauna, the wild hogs have become a major management problem within the park. During the summer of 1973, quadrat sampling of the canopy and understory of Gray Beech Forest was conducted in both the hog—free and hog—occupied sectors of the park. Removal of the herbaceous understory and other types of hog rooting damage showed no direct relationship to the importance of any individual canopy species, including beech Fagus grandifolia. Cover reduction was related, however, to the importance of mesic herbs in a plot. Polynomial and Gaussian regressions of cover against indirect ordination axes indicate that hog rooting within Gray Beech Forest is most intense in the mesic portion of the moisture gradient and decreases both on xeric, south—facing slopes and on more mesic, north—facing slopes. Understory cover in the most severely damaged plots was between 2% and 15%, while understory cover in hog—free plots in the same position on the moisture gradient was usually between 80% and 110%. Hog rooting significantly reduced the number of species in the most disturbed plots but had no effect on the H' values of the largest plot sizes sampled. High H' values for the damaged plots are related to the lack of succession after disturbance of the understory without removal of the canopy.