Master of Science (MS), Wright State University, 2012, Biological Sciences

Garlic mustard (Alliaria petiolata) has been previously found to be significantly affected negatively by powdery mildew (Erysiphe cruciferarum). While we could not significantly corroborate those findings we did find evidence that E. cruciferarum does inhibit A. petiolata's allelopathic and competitive effects which benefits some target neighbor species such as Impatiens capensis and Elymus canadensis. We also found that the inhibition of A. petiolata by E. cruciferarum had negative consequences on another neighboring invasive species (Lonicera maackii) compared to those grown next to uninfected A. petiolata. Acer saccharum, a slow-growing species had no effect between neighbors. Sterilization treatments had variable effects on target plants, many of which mirror the effects which allelopathic plants (A. petiolata) that disrupt soil microbes seem to have. Sterilization inhibited growth of E. canadensis through the destruction of beneficial effects from microbes, while increasing the growth of L. maackii by inhibiting the pathogenic effects of microbes.

Committee: Don Cipollini Ph.D. (Advisor); James Amon Ph.D. (Committee Member); Thomas Rooney Ph.D. (Committee Member) Subjects: Biology; Botany; Conservation; Ecology; Environmental Management; Forestry; Plant Biology; Plant Pathology; Plant Propagation; Plant Sciences; Wildlife Conservation

Master of Science (MS), Ohio University, 2012, Environmental and Plant Biology (Arts and Sciences)

Documenting change in the composition and structure of forest communities is important for understanding the distribution and abundances of natural resources, carbon pools, and species. Here, results are presented from the second sampling effort at Dysart Woods, an old-growth, mixed-mesophytic remnant tract in southeastern Ohio. In 2011, trees, saplings, shrubs, herbs, and soils were sampled in permanent plots established in 1996, allowing a direct fifteen–year comparison. Mortality and recruitment rates revealed that while most species at Dysart Woods are decreasing in abundance, sugar maple and American beech are rapidly increasing in importance, as is the invasive Alliaria petiolata. This shift in composition may be due to beech and sugar maple showing little negative responses to neighbors, and/or reflect increasing pressures that old-growth forests face from invasives. Such findings have considerable implications for the future of Dysart Woods, and developing appropriate management techniques may be required to preserve its integrity.

Committee: Brian McCarthy PhD (Advisor); Glenn Matlack PhD (Committee Member); Jared DeForest PhD (Committee Member) Subjects: Botany; Ecology; Forestry