Doctor of Philosophy, The Ohio State University, 2015, Evolution, Ecology and Organismal Biology

Planting of semi-domesticated grasses for habitat restoration and bioenergy has raised concerns about potential ecological consequences, for instance, genetic swamping of wild populations through crop-to-wild gene flow, and introgression of crop traits into wild relatives resulting in more invasive wild populations. In this dissertation, I explored different aspects of gene flow in two popular bioenergy candidates — switchgrass (Panicum virgatum) and Miscanthus (Miscanthus spp.) — and aimed to provide necessary information to mitigate potential gene flow from new switchgrass and Miscanthus cultivars. Switchgrass cultivars have been planted in Conservation Reserve Program (CRP) areas when wild seed sources are limited. However, the close proximity of CRP areas and remnant prairies may have allowed rapid crop-to-wild gene flow. In the first chapter, I investigated ploidy levels, genetic diversity, and genetic structure of seventeen prairie and sixteen CRP populations in eastern Kansas, along with five standard cultivars. The results suggested that the prairie and CRP populations were genetically similar, and the CRP populations were mainly established using local prairie seeds rather than cultivars. In addition, the prairie populations still harbor unique alleles that are of conservation value. Sufficient isolation distance between cultivated plants and their wild relatives is essential to prevent crop-to-wild gene flow, especially when the crop carries transgenes. In the second chapter, I documented the pattern and predicted the extent of pollen-mediated gene flow in switchgrass using two small field experiments with ~100 pollen donor plants and regression models. Data suggested that the pattern of gene flow was best described by a negative exponential model, and the estimated minimum isolation distance for a threshold of 0.01% gene flow was 60m and 109m for the experimental arrays. Seed-mediated gene flow could result in volunteers when favorable conditions (open full item for complete abstract)

Committee: Allison Snow (Advisor); Kristin Mercer (Committee Member); Maria Miriti (Committee Member); Andrea Wolfe (Committee Member) Subjects: Ecology

Master of Science, The Ohio State University, 2014, Environment and Natural Resources

Early successional habitat and grasslands declined across the United States over the last 50 years. This decline is detrimental to both plant and wildlife diversity. The trend is particularly strong throughout the Midwest. Land conservation programs, such as the Conservation Reserve Program (CRP), provide farmers financial incentives to engage in a specific land conservation practice for a period of 10-15 years. Programs such as the CRP can help to combat the loss of early successional habitat; however the programs are conducted via voluntary enrollment. Therefore, understanding factors influencing farmers' decisions to enroll in the CRP, and specifically what factors could increase their willingness to enroll are important to explore. I explored farmer's subjective norms, trust in federal agencies, risk tolerance, self-efficacy, demographic factors, and perceived costs and benefits of the program and their effect on farmer's willingness to enroll in the CRP. A mail-back survey was administered to 6000 farmers in six counties in Ohio. Results indicate that costs and benefits, specifically perceived environmental health benefit is the most important indicator of willingness to enroll in CRP. Geographic region may also influence which factors are most indicative of overall willingness to enroll.

Committee: Jeremy Bruskotter (Advisor); Robyn Wilson (Committee Member); Robert Gates (Committee Member) Subjects: Environmental Studies; Natural Resource Management; Sustainability

Master of Science, The Ohio State University, 2011, Environment and Natural Resources

Despite a long history of research and accumulated knowledge of factors affecting population growth rates, conservation efforts aimed at reversing population declines of northern bobwhites (Colinus virginianus) have been largely ineffective. Bobwhite population decline and range contraction across the Midwest was driven primarily by changes in land-use practices related to large-scale intensive agriculture, urbanization, and forest succession. Although changes in agricultural landscapes have contributed substantially to the decline, such landscapes remain the only area where active management may improve population growth rates. To understand the ecology of bobwhites in agricultural landscapes in Ohio, I used radio-telemetry to investigate survival and habitat use during the non-breeding season (October–March) on 4 private land study sites in southwestern Ohio during 2009-2011. Known-fates survival estimates were low in both years (S2009-2010=0.05, 95% CI=0.03, 0.11, S2010-2011=0.12, 95% CI=0.07, 0.20) and lowest weekly survival coincided with periods of prolonged snow cover. Compositional analysis revealed that coveys used habitat non-randomly at 3 scales; positioning of home ranges within study areas (Λ = 0.320, P < 0.001), positioning of core areas within home range (Λ = 0.599, P = 0.002), and point locations within home ranges (Λ = 0.058, P = 0.002). Early successional woody vegetation (e.g. fencerows and ditches) was the most preferred habitat type at all scales. Differences in selection among study sites revealed that home ranges were preferentially established in areas with grassland cover on 2 agricultural study sites, but not at the site with the greatest amount of grassland cover. Bobwhites mostly used habitat edges such that interior portions of grass and crop fields were used less as they increased in area. Thus small fields with high edge to interior ratios are most advantageous. I tested the influence of habitat use on individual survival by comparing (open full item for complete abstract)

Committee: Robert Gates PhD (Advisor); Amanda Rodewald PhD (Committee Member); Stanley Gehrt PhD (Committee Member) Subjects: Ecology; Natural Resource Management; Wildlife Conservation; Wildlife Management

Master of Science, The Ohio State University, 2009, Environmental Science

The Conservation Reserve Program (CRP) was established by the Food SecurityAct of 1985 to pay farmers to retire highly erodible and environmentally sensitive cropland and pasture from production. These retired lands have been under increased pressure for conversion to row crops given the relatively high crop prices that have prevailed until recent months. This thesis compared CRP land to row crop production using three methods financial analysis, economic analysis, and emergy evaluation. This project also considered the possibility of using CRP land for bioenergy production in Ohio and considered how much farmers would need to be paid for their biomass to make harvesting a financially optimal choice. A financial analysis was carried out to determine which factors would have the greatest influence on whether farmers will put conservation land back into production. The analyses showed that with high corn and soybean prices, $5.25 and $13.30 per bushel respectively, crop production almost always had higher returns than CRP. However, under lower crop prices, $3.25 and $7.70 per bushel respectively, CRP land always had a higher return. To address the economic value of CRP crop production, this analysis considered the benefits and costs to society of having land enrolled in either system. The results of this analysis show the economic value of average productivity CRP land to be -$19.01 per acre per year. This means the cost of CRP to society is greater than its benefits. However, CRP is still economically superior to crop production, except under the highest crop prices considered. Emergy evaluation was used to compare the sustainability of CRP land and crop production (corn and soybeans) using an ecologically based methodology. CRP land was shown to be more sustainable than corn and soybean production due to its reliance on renewable inputs. The study also suggested that incoming soil erosion and water runoff from adjoining fields are two of the most important inputs to (open full item for complete abstract)

Committee: Fredrick Hitzhusen PhD (Advisor); David Barker PhD (Committee Member); Frederick Michel PhD (Committee Member) Subjects: Agriculture; Economics; Environmental Science