Billak, Brittany (University of Virginia). Mentor: Tami Ranson (University of Virginia). Factors influencing the distribution of invasive earthworms in Southern Appalachia.

Abstract: Unlike states in the northeast where most of the recent research examining North American earthworms has occurred, Virginian soils are inhabited by both native and invasive earthworms. Little is known about the interactions between native and invasive earthworms. To determine the factors influencing the distribution of invasive earthworms in Southern Appalachia , field transects located at four suspected sites of introduction were sampled for earthworms. We also conducted a laboratory experiment comparing the performance of an invasive earthworm ( Lumbricus terrestris ) to that of a native earthworm ( Eisenoides carolinensis ) at different temperature and moisture treatments. Mean number of invasive earthworms per m 2 decreased as distance from the forest edge increased; native earthworms displayed the opposite relationship. Trends suggested that L. terrestris performs worse at higher temperatures, and E. carolinensis performs better at higher moistures. Our results suggest several possible reasons for why invasive earthworms are not abundant in the forests of Southern Appalachia : differences in soil characteristics between fields and forests; invasive earthworm preference for areas with higher human disturbance; and competition with native species.