Master of Science (MS), Wright State University, 2009, Biological Sciences

Garlic mustard is an invasive Eurasian biennial that has rapidly spread throughout the United States. In Southwestern Ohio, many garlic mustard populations are infected with the powdery mildew Erysiphe cruciferarum that can reduce the growth and fitness of garlic mustard. E. cruciferarum was assessed using a Decision Tree in regards to its potential use as a biological control agent. I determined the distribution of E. cruciferarum on garlic mustard and I determined the potential risk of E. cruciferarum to native Brassicaceous species and selected crops. I surveyed 19 parks in Southwestern Ohio and recorded the number of diseased garlic mustard and aspect at every population and then made a distribution map of disease incidence of E. cruciferarum on garlic mustard using GIS ESRI (ArcMap) software. My distribution survey showed a random distribution of E. cruciferarum infection on garlic mustard with disease incidence decreasing away from Dayton, Ohio. Aspects with higher disease incidences were level and facing southeast and were significantly different than northwest facing aspects. Five native spring ephemeral species were surveyed in the field and then obtained from local wooded areas in May 2008. Individual plants were transplanted in the greenhouse and then exposed to infected garlic mustard plants. The native plants surveyed showed no obvious signs of E. cruciferarum infection in the field. All of the native plants subjected to powdery mildew under greenhouse conditions became mildly infected with E. cruciferarum. Twelve crops in the family Brassicaceae along with 2 crops in the Fabaceae and Solanaceae families were planted and inoculated with E. cruciferarum and only one cultivar, Savanna Mustard (Brassica juncea), became infected with powdery mildew. A distribution survey showed the distribution of E. cruciferarum infection on garlic mustard with disease incidence decreasing away from Dayton, Ohio. Populations located on level ground or facing southeast had (open full item for complete abstract)

Committee: Don Cipollini PhD (Advisor); Thomas Rooney PhD (Committee Member); Songlin Cheng PhD (Committee Member); David Goldstein PhD (Other); Joseph F. Thomas, Jr. PhD (Other) Subjects: Biology; Botany; Ecology

Master of Science (MS), Wright State University, 2022, Biological Sciences

Garlic mustard is an invasive Eurasian biennial spreading in deciduous forests of North America. Garlic mustard plants in Ohio can be infected with a strain of Xanthomonas campestris, the causal agent of black rot disease in brassicas. I examined variation in susceptibility to X. campestris among garlic mustard populations, several native wild species, and agricultural crop varieties. Twenty-four garlic mustard populations were universally susceptible to X. campestris, though disease severity varied. Cardamine concatenata and Cardamine diphylla were susceptible but can phenologically escape infection in the field. Of the 14 agricultural crops tested, three cultivars (Raphanus sativus, Brassica rapa var. Rapa Hakurei, and cv - Brassica oleracea var. capitata) were susceptible to the X. campestris strain that infects garlic mustards. Nutrient availability enhanced disease susceptibility and severity, but light had a limited effect. A survey of 31 garlic mustard populations in Ohio, Kentucky, and Indiana revealed that X. campestris is established throughout a 120 km radial distance from Dayton, Ohio. The strain of X. campestris infecting garlic mustard in the Wright State University woods was identified by sequencing as X. campestris pv. incanae.

Committee: Donald Cipollini Ph.D. (Advisor); John O. Stireman III Ph.D. (Committee Member); Volker Bahn Ph.D. (Committee Member) Subjects: Biology; Botany; Ecology; Plant Biology; Plant Pathology

Master of Science (MS), Ohio University, 2015, Plant Biology (Arts and Sciences)

Since the loss of Castanea dentata (American chestnut) from eastern hardwood forests, invasive species have occupied many of the forests where chestnut once resided. Even though agencies have begun to replant hybrid chestnuts into the forests, no one has examined how invasive species might interact with American chestnut. In this study, allelopathic impacts on chestnut were mimicked by adding aqueous extracts or biomass of three allelopathic invasive species tree of heaven (Ailanthus altissima (Mill.) Swingle), garlic mustard (Alliaria petiolata (M.Bieb.) Cavara and Grande), and Amur honeysuckle (Lonicera maackii ( Rupr. ) Maxim.)) to soils supporting chestnut seedlings. In greenhouse experiments, chestnut seeds were treated weekly with aqueous extracts of biomass from the invasives. Chestnut seedlings were also planted in gardens and treated with root or shoot biomass from the invasives. Finally, chestnut seedlings were planted in a forest at sites with garlic mustard present and at sites where garlic mustard had been regularly removed for 8 yrs. Growth factors of chestnut, such as height, mass, and basal area, were measured. Chestnut seedlings treated with tree of heaven extracts had lower heights and more re-sprouts than the control groups. However, results were not consistent among the experiments. Chestnut seedlings treated with some invasive plant biomass, including tree of heaven biomass, had heights statistically similar to the control groups. When treated with roots of garlic mustard, chestnut heights were statistically lower than the negative control. Chestnut seedlings planted in garlic mustard plots in the forest were only statistically taller the first time they were measured, but were not statistically different thereafter. The results from these initial experiments suggest that the allelopathic effects from tree of heaven may negatively impact reintroduction of American chestnut; however, other invasives may be less problematic.

Committee: Brian McCarthy Dr. (Advisor); Jared Deforest Dr. (Committee Member); David Rosenthal Dr. (Committee Chair) Subjects: Ecology; Plant Biology

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

Our goal was to characterize the interactive feedback between garlic mustard (Alliaria petiolata) and European earthworm species in southwest Ohio. Earthworm community composition, abundance and biomass were compared between 0.1 m2 plots of garlic mustard, cut-leaved toothwort (Cardamine concatenate), wild ginger (Asarum canadense), or no plant cover. Exotic earthworms were present in the study site. Earthworm abundance and biomass did not correlate with garlic mustard percent cover. There was a greater density of earthworms in the fall than in the spring. Worm abundance differed between garlic mustard and wild ginger plots and cut-leaved toothwort and control plots, suggesting that earthworms may prefer to be located under plants that produce high biomass. Worm biomass did not differ between the plants. There was a greater abundance of endogeic worms below all plants, while anecic worms contributed the most biomass. Our results do not support strong feedback between garlic mustard and European earthworms.

Committee: Thomas Rooney PhD (Advisor); James Runkle PhD (Committee Member); Don Cipollini PhD (Committee Member) Subjects: Biology; Ecology

Master of Science, University of Toledo, 2010, Biology (Ecology)

Extracellular enzymes are produced by both microbes and plants and directly mediate organic matter breakdown. These enzymes can be present on root surfaces or secreted by roots into the rhizosphere and are used to exploit pools of organic nutrients in the soil. Extracellular enzymes secreted by plant roots have received little attention outside of a few studies examining enzyme production on a small scale or in artificial/intensely managed environments. As a result, little is known about the extent of root enzyme activity and the degree to which these enzymes can be used by roots to exploit pools of organic nutrients in the soil. Additionally, comparative studies between native and invasive exotic plant root extracellular enzyme capabilities are lacking. To address these knowledge gaps, the objective of this study was to characterize the activities of a variety of nitrogen and phosphorus acquiring enzymes on the roots of a diverse range of native and invasive exotic plants. High rates of phosphatase and chitinase activity were observed on the roots of all plant sampled compared to the surrounding soil. Rates of root phosphatase activity were the highest ever recorded in our laboratory, even exceeding rates of 14,000 nmol/h/g on roots of the non-mycorrhizal invasive herb Alliaria petiolata (garlic mustard). Roots were also examined for two types of peptidases, leucine amino peptidase and glycine amino peptidase. No roots had any significant glycine amino peptidase activity, while a small proportion exhibited relatively low rates of leucine amino peptidase activity. Regressions comparing nutrient levels and enzyme activity showed no significance, but a few significant relationships were observed with the plants Lonicera maackii (honeysuckle), Acer rubrum (red maple), and A. petiolata. Comparing invasive exotic and native plants yielded no significant comparisons save that A. petiolata again had significantly higher leucine amino peptidase and phosphatase activity than (open full item for complete abstract)

Committee: Michael Weintraub (Advisor); Elliot Tramer (Committee Member); Scott Leisner (Committee Member) Subjects: Botany; Ecology; Environmental Science

Master of Science, University of Toledo, 2009, Biology (Ecology)

Garlic mustard (Alliaria petiolata) is a biennial herb, native to Eurasia that may have been imported to North America in the 1800's and since has invaded most of the Eastern and Midwestern United States. It possesses allelopathic compounds in its leaf litter and root exudates that have been found to decrease the presence of arbuscular mycorrhizal fungi and suppress the germination of several hardwood tree species and other mycorrhizal species in several studies. Suppression of mycorrhizae suggests possible effects of garlic mustard on other soil microorganisms, and preliminary studies show impacts on bacterial community diversity and extracellular enzyme activity. I examined the effect of garlic mustard densities on soil enzyme activity in three forested sites in Northwest Ohio. Garlic mustard density gradients were identified at each site, and each gradient was divided into areas of high, medium and low density. A manipulative weeding experiment was also performed on other plots of high-density garlic mustard: plots were divided in half and one side was weeded for garlic mustard whereas the other half remained a control. Monthly soil samples from both experiments were analyzed for enzyme activity, nutrient availability and microbial carbon and nitrogen content. Stepwise regressions produced few models that included garlic mustard density as a predictor of enzyme activity, however the results suggest that garlic mustard density significantly affects N-acetyl-glucosaminidase, an enzyme associated with chitin breakdown. A multivariate analysis of variance (MANOVA) of all transect data suggested that nitrogen availability and cycling rates are increased in the presence of garlic mustard, however the results of the manipulative weeding experiment were less indicative of this relationship. The MANOVA for the split-plot weeding experiment revealed several significant differences in enzyme activity, however some of these differences may be due to physical disturbance at o (open full item for complete abstract)

Committee: Dr. Daryl L. Moorhead PhD (Committee Co-Chair); Dr. Michael N. Weintraub PhD (Committee Co-Chair); Dr. Alison L. Spongberg PhD (Committee Member) Subjects: Ecology; Environmental Science

Master of Science, University of Toledo, 2009, Biology (Ecology)

Recent studies have shown that exotic plant species can have wide-ranging effects on soil ecosystem processes and biotic diversity, and those effects may be more extensive than previously thought. Garlic mustard [Allliaria petiolata (M. Bieb.) Cavara and Grande] is an exotic, invasive herb that poses a threat to North American forests by reducing native plant performance and recruitment. However, little is known about potential impacts to belowground communities and processes. The object of this study was to determine the effects of A. petiolata on soil physical, chemical, biogeochemical, and biotic properties. Soil samples were collected between October 2006 and February 2008 from plots with A. petiolata present or absent in three Ohio forests: the University of Toledo Stranahan Arboretum (Arboretum), Fuller Preserve (Fuller), and South Park (South). Variables measured included moisture content, pH, organic matter (SOM), nutrient dynamics [dissolved organic carbon (DOC), microbial biomass carbon (Cmic), dissolved organic nitrogen (DON), microbial biomass nitrogen (Nmic), ammonium, nitrate, and phosphate], microbial community function [activities of acid phosphatase (PHOS), α-glucosidase (AG), β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), β-D-cellobiohydrase (CBH), β-xylosidase (BXYL), leucine amino peptidase (LAP), urease, phenol oxidase (phenox), and peroxidase (perox)], and microbial community structure [community DNA profiles, Simpson index (D), Shannon index (H'), and richness (S)]. Results showed that A. petiolata presence had a significant affect on only approximately one third of the measured variables. Generally, the variables affected and the direction of effects (positive or negative) were inconsistent both spatially and temporally. Soil moisture, SOM, Nmic, DOC, phosphate, BG activity, ratio of C- to P-acquiring enzyme activities (C:P), and bacterial richness and diversity were lower with A. petiolata present at Arboretum, but most treatment diff (open full item for complete abstract)

Committee: Daryl Moorhead PhD (Advisor); Michael Weintraub PhD (Advisor); William Von Sigler PhD (Committee Member) Subjects: Biology; Ecology; Environmental Science

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

Disturbance such as forest management is thought to promote invasive species spread. This study uses population demography to address the spread of the invasive species Ailanthus altissima, Alliaria petiolata, and Microstegium vimineum in forested sites in southeast Ohio. Invasive species populations were examined in the silvicultural treatments prescribed burn and timber harvest, plus control plots with no management. Seed rain, seedling establishment, and the soil seed bank was studied for each population. All invasive seeds formed a persistent seed bank and experienced seasonal dormancy, but the proportion of dormant seeds varied among species (p<0.05). Slope aspect effected seed survivorship and dormancy (p<0.05) for each species. Dormancy for each species showed no relationship or a weak relationship with time since seed burial. Invasive populations expanded at a constant rate among treatments, and invasive seeds changed dormancy conditions seasonally to allow for germination during favorable conditions, which may contribute to invasive ability.

Committee: Glenn Matlack PhD (Advisor); Stefan Gleissberg PhD (Committee Member); Harvey Ballard PhD (Committee Member) Subjects: Botany

Master of Science, Miami University, 2008, Botany

Exotic plant invasion may result in the disruption of symbioses between plants and soil biota, potentially affecting plant fitness and community composition. I tested whether the invasive biennial Alliaria petiolata (garlic mustard) affects abundance and community composition of ectomycorrhizal fungi (EMF) associated with experimentally planted Quercus rubra (northern red oak) seedlings. Proportional EMF colonization, EMF species richness and diversity, and Q. rubra survival were lower for seedlings in a stand with high density A. petiolata than in a stand without A. petiolata. Community composition of EMF also differed between stands. A comparison of naturally occurring Q. rubra seedlings in a moderate vs. a low density site showed a trend toward less EMF with more A. petiolata, while richness and diversity did not differ. Though confounded by uncontrolled environmental variables, these results are consistent with A. petiolata negatively impacting ectomycorrhizal fungi, warranting more research on this indirect effect on native plants.

Committee: David Gorchov (Advisor); Nicholas Money (Committee Member); Charles Kwit (Committee Member) Subjects: Botany; Ecology

Master of Science, Miami University, 2006, Botany

The impact of invasive plant species on native plants is largely assumed to be negative, but supporting evidence is sparse. We examined the long-term effects of herbicide on Alliaria petiolata and the subsequent effects on the plant community in southwestern Ohio. November herbicide application effectively killed A. petiolata, but did not reduce recruitment; spring densities of A. petiolata rosettes were not lower in sprayed plots. Only modest differences were noted in forest floor vegetation, suggesting A. petiolata rosettes competed with other plant species. We tested the hypothesis that higher June precipitation promotes rosette growth and survival with a rain shelter experiment. The three different water treatments affected soil moisture, but not A. petiolata growth or survival. Dry treatments may not have replicated drought years based on water availability measurements. June precipitation is probably not a reliable predictor of A. petiolata rosette survival in years with above average precipitation.

Committee: David Gorchov (Advisor) Subjects:

Doctor of Philosophy in Regulatory Biology, Cleveland State University, 2010, College of Sciences and Health Professions

Urbanization has resulted in massive transformation of natural habitats with profound effects on biodiversity. Addressing the problems associated with anthropogenic deterioration of the environment requires solid understanding of the factors driving these changes. Habitat patch size, edge effects, and the presence of invasive species are among the key features of the urban landscape affecting local communities. My study focused on the effects of habitat edges, the exotic ant Nylanderia flavipes, and the invasive herb garlic mustard on local ant diversity in deciduous forest fragments of northeastern Ohio. In addition, I explored the value of common ant collecting techniques for estimating ant diversity. When compared to pitfall trapping, Winkler litter extraction showed greater species richness and higher abundance of ants and exhibited the advantage of a more complete inventory. Winkler extraction may completely replace pitfall trapping in temperate forests with well-developed litter layer, and inventorying programs may benefit from the inclusion of this technique as a rapid and effective ant-collecting tool. Our study documents predictable edge-associated changes in species richness, community composition and functional groups, occurring in local forest ant assemblages. Edge effects are most pronounced within the first 25m, which may have implications for the conservation of forest-dwelling fauna. At the sites where Nylanderia flavipes occurred, we found a 6-fold increase in ant abundance, with 87% of the ants being N. flavipes. The numerical dominance of this species did not lead to detectable changes in the species richness and abundance of the native ant community, but was responsible for decreased community evenness. This is likely indicative of a recent introduction with populations still being in their latency period. The high local abundance of N. flavipes may give it a competitive advantage and affect native ants through exploitative competition. Plots inv (open full item for complete abstract)

Committee: Joe Keiper PhD (Advisor); Michael Walton PhD (Committee Member); Robert Krebs PhD (Committee Member); Jaharul Haque PhD (Committee Member); Daniel Petit PhD (Committee Member); Paul Doerder PhD (Other); Carl Anthony PhD (Other) Subjects: Ecology

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