Master of Science (MS), Bowling Green State University, 2020, Biological Sciences

As headwaters transporting agricultural runoff to streams and lakes, agricultural ditches may be a key component to reducing nutrient loading and harmful algal blooms. While conventional trapezoidal ditches are the most widely used, two stage ditches and self-forming streams are starting to be constructed as a means of management. Two stage ditches and self-forming streams may be useful for their wider floodplains, allowing slower movement of water and less erosion, promoting environments that retain and remove more nutrients than the more narrow conventional ditches. Here I examined multiple nutrient pools and fluxes (plants, invertebrates, sediments, water, and biofilm) of phosphorus and nitrogen in both May and July of 2018. I also tested the effects of isopods on nutrient cycling in ditch sediments in laboratory experiments. The results showed that ditch morphology did little to impact the concentration of nutrients, but did alter nutrient density and total nutrient retention, which was related to the width of the ditch. Plant and sediment pools were found to retain the most nutrients. Self-forming streams retained the most nutrients but supported a low biomass and diversity of invertebrates which can be important in nutrient cycling and multiple ecosystem functions. Bioturbation was found to be less important than excretion with invertebrates that rework surface sediments. Overall, my results suggest two stage ditches may balance increased nutrient retention while at the same time maintain aquatic habitat quality.

Committee: Kevin McCluney Dr. (Advisor); Enrique Gomezdelcampo Dr. (Committee Member); James Hood Dr. (Committee Member); Helen Michaels Dr. (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Biology; Ecology; Geomorphology; Hydrology; Water Resource Management

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

Northwest Ohio has been heavily impacted by ditching and draining of the landscape as well as impoundment and pond construction. These features can reduce baseflows, alter wetland hydroperiods, or otherwise impair ecosystem services. However, they may also create aquatic habitat, serve as refuges from wetland habitat loss and promote connectivity of wildlife populations. It is critical to identify the effects of hydromodification on semiaquatic fauna such as the common muskrat (Ondatra zibethicus), the American mink (Neovison vison) and cambarid crayfishes (Cambaridae), which may be sensitive to associated changes in fine- and coarse-scale wetland habitat and landscape characteristics. To evaluate potential wetland habitat use patterns, sign and nocturnal spotlight surveys were conducted in the Oak Openings Region from May 15th to October 18th 2021. Habitat, environmental and spatial data were also collected. As predicted, focal organisms used modified wetlands to a lesser degree, although the effect depended on organism and wetland type. As expected further, muskrats and crayfishes were more likely to use higher order or deep streams/ditches; crayfishes were more likely to use seasonal and restored wetlands. Results were consistent with isolation-area based predictions of habitat use insofar as mink and muskrats were more likely to use large nonlinear wetlands, and muskrats used less isolated wetlands. Crayfish and, unexpectedly, mink used more isolated wetlands. Open canopy and anthropogenic landcover classes in the landscape neighborhood of wetlands featured in many habitat use models. Fine-scale habitat variables tended to predict habitat use as well as or better than coarser-scale variables. Treating presence or relative activity of each organism as a predictor variable in habitat use models of the other organisms produced competitive models, although results for mink occurrence were inconsistent with predictions based on predator-prey relationships. Results su (open full item for complete abstract)

Committee: Karen Root Ph.D. (Committee Chair); Enrique Gomezdelcampo Ph.D. (Committee Member); Jeffrey Miner Ph.D. (Committee Member) Subjects: Biology; Ecology; Wildlife Conservation; Wildlife Management

Master of Science (MS), Bowling Green State University, 2019, Biological Sciences

Predators of crop insects are influenced by a number of variables which affect their foraging in agroecosystems. Though many of these predators, and their movement between crop and non-crop habitats, has been documented, the impact of variation in non-crop habitats is less understood. Here, we sought to understand how ditch geomorphology and prey availability at ditches and cornfields influences the potential spillover of web spiders, ground spiders, and bats. We examined 10 farms across Northwest Ohio, each possessing either a narrow conventional ditch, wider two-stage ditch, or very wide self-forming stream ditch. At each site, we surveyed and collected prey and predators along a transect extending from the ditch up to 200m into the adjacent cornfield, and conducted stable isotope analysis on samples. Stable isotope analysis (δ13C & δ15N) revealed that both web and ground spiders along ditches consume more prey that ate C3 vegetation (e.g. possibly emergent insects or ditch herbivores), while spiders in the fields consume mostly prey that ate C4 vegetation (possibly pests of corn). Guano isotopes indicate bats have highly variable prey consumption (median value around 38.3% of diet made up of C4,with large credible intervals). Web spiders were more abundant along ditches but increased in fields over the course of the season (p=0.001). Bat activity was higher at ditches than in adjacent cornfields in July-August, with both high and low aquatic insect emergence. However, August-September bats showed higher activity deep within the fields during periods of high aquatic prey availability at ditches (p=0.032). Isotopes suggest that spiders do not spillover between ditches and fields, but they were abundant in fields and ate prey with a C4 (corn-based) diet. Recording data and isotopes together suggest bats do consume prey from both ditches and cornfields. Ditch geomorphology was not found to have an effect on the response of abundance or activity of predators and prey (open full item for complete abstract)

Committee: Kevin McCluney PhD (Advisor); Jessica D'Ambrosio PhD (Committee Member); Karen Root PhD (Committee Member) Subjects: Agriculture; Biology; Ecology

Master of Science (MS), Bowling Green State University, 2018, Biological Sciences

Floodplain geomorphology and vegetation are important factors influencing nutrient loading into streams and in-stream processing. Natural floodplains encourage the flow of water through intricate subsurface flow-paths, allowing more time for phosphorus and nitrogen utilization by microbes and plants. Many agricultural fields in northwest Ohio use subsurface tile drain systems that deliver excess water directly into channels, bypassing groundwater flow. These channels tend to have little to no bank and/or vegetation which poses problems with excessive nutrient run-off. Self-forming streams restore agricultural ditch channels to mimic natural stream processes and stimulate vegetation growth. Two-stage ditches incorporate a floodplain zone into the channel bench, mimicking natural processes of stable streams. Both of these restoration options might help reduce nutrient fluxes downstream via increased retention. However, removal of phosphorus from ditches and streams back to the landscape requires animal-mediated movements, but these fluxes have not been well quantified. The research described here quantified potential effects of restoration of ditches and stream and watershed characteristics on fluxes of emergent insects and fluxes of phosphorus contained within these insects. Twenty sites in northwest OH were sampled from July thru September 2016, with sites varying in floodplain geomorphology and vegetation (e.g. conventional channels, natural streams with and without vegetation, two stage ditches, and self-forming streams) and watershed characteristics. Overall, this research did not find a significant effect of restoration practices on phosphorus (P) fluxes of emergent invertebrates at the alpha = 0.05 level, despite a significant effect on biomass of emergent insects (p= 0.036). On the other hand, both biomass (p=0.040) and P flux (p=0.042) were influenced by watershed land use, with a decline in both with increasing urbanization. Additionally, P content of emerg (open full item for complete abstract)

Committee: Kevin McCluney Dr. (Advisor); Enrique Gomezdelcampo Dr. (Committee Member); Shannon Pelini Dr. (Committee Member) Subjects: Biology; Ecology

Master of Science (MS), Bowling Green State University, 2017, Geology

Many natural ecosystems are in decline due to anthropogenic disturbance and conversion for human development. Conservation efforts have focused on reserves as the primary location for conservation of native diversity however they are fragmented and embedded in a matrix of potentially inhospitable landscape features. Native ecosystems can also be found in marginal ecosystems, such as riparian buffers, ditches, and field margins, but have been overlooked as contributors to native diversity because thy are small and highly invaded. For my thesis I evaluated the conservation value of marginal ecosystems to support plant diversity compared to reserve areas. I used the point-intercept method to identify species presence along two 10 meter transects in 58 ditches and 26 reserves in northwest Ohio. I characterized diversity with 3 indices: species richness, Shannon diversity index, and rarity weighted richness. I used a Hotelling's t-test to compare diversity between ditches and reserves. I evaluated local and regional land use using a modified Daubenmire frame, the National Land Cover Database, and the National Agricultural Statistics Service's Cropland dataset to calculate cropland variation from 2006-2015. I used Geographically Weighted Regressions and linear regressions to assess the influence of local and regional land use on plant diversity and milkweed (Asclepias spp.) distribution. I found that ditches are similar to reserves in maintaining native diversity and contain native species exclusively found in ditches. Secondly, I found diversity is more influenced by local factors and, despite being different landscape contexts, there is no spatial pattern to diversity. Lastly, I found more area of high quality milkweed habitat exists in ditches than reserves. While there are many native species found in reserves, ditches are also highly invaded and ditches can be thought of as hybrid ecosystems. Although ditches are highly invaded, they are an extensive, highly intercon (open full item for complete abstract)

Committee: Andrew Gregory PhD (Advisor); Enrique Gomezdelcampo PhD (Committee Member); Helen Michaels PhD (Committee Member) Subjects: Biology; Biostatistics; Botany; Conservation; Ecology; Environmental Science; Geology; Geomorphology; Land Use Planning; Plant Biology; Quantum Physics; Wildlife Conservation

Master of Science, The Ohio State University, 2010, Food, Agricultural and Biological Engineering

There were five objectives addressed in this thesis: 1) evaluation of the evolution of two-stage ditches in a tri-state region in the upper Midwest, USA; 2) developing a unit hydrograph that accounts for subsurface drainage discharges into surface collection ditches; 3) evaluation and/or enhancement of the developed unit hydrograph method for extreme events; 4) estimation, at a reach scale of, the percentage of peak flood reduction in five constructed two-stage ditches; and 5) estimation of the influence on flow discharges of constructing two-stage channels along all surface ditches within a watershed. Objective 1 or channel evolution evaluation was performed on 5 two-stage ditches from Michigan, Ohio and Indiana with watershed sizes ranging between 2 to 6 mi2. The following ditches were evaluated: Crommer Ditch in Hillsdale County, Michigan; Klase Ditch in Shelby County, Ohio; Bull Creek of Hancock in Ohio; Creel Ditch in Steuben County, Indiana; and Shatto Ditch in Kosciusko County in Indiana. System evolution was evaluated to determine if ditches were assuming a state of quasi-equilibrium or defined as the morphological change in the stream channel that occurs as a stream seeks for greater channel stability. Evolution evaluation indicated that Crommer Ditch was in a state of quasi-equilibrium. Klase Ditch was evolving towards a state of quasi-equilibrium. Bull Creek downstream segment was in a state of quasi-equilibrium; whereas, the upstream segment was still evolving. At Shatto Ditch may be evolving towards a state of quasi-equilibrium. The double-triangle unit hydrograph method was used to modeling the hydrology of agricultural ditches receiving subsurface agricultural drainage. Gowda et al. (1999) double triangle unit hydrograph method, and four curve fitting techniques were evaluated to determine which parameters best account of subsurface drainage. Curve fitting technique 4, which had neglected the watershed land properties, best predicted the measured stor (open full item for complete abstract)

Committee: Andy D. Ward PhD (Advisor); Jon D. Witter PhD (Committee Member); Larry C. Brown PhD (Committee Member) Subjects: Agricultural Engineering

Doctor of Philosophy, The Ohio State University, 2013, Food, Agricultural and Biological Engineering

We provide a critical review of the massive land drainage works, water resource degradation and a persistent eutrophication problem in agriculturally-dominated watersheds, such as the Gulf of Mexico and the Great Lakes, which have led to examination of managing agricultural drainage ditches for ecosystem benefits. Work by dissertation collaborators on alternative ditch designs has led to the two-stage ditch approach, which creates floodplain benches stabilized by vegetation and an inset channel that effectively transports water and sediment based on channel-forming discharge concepts. The goals of the approach are to create stable, well-vegetated ditches that can reduce localized flooding and bank erosion problems while maintaining drainage capacity such that frequent maintenance will be reduced or unnecessary over the life of the ditch. Evaluating seven two-stage ditches in Ohio, Indiana, and Michigan we found that 3-10 years after construction all of the ditches constructed exhibited small adjustments to the inset channel, have remained stable, and have achieved the goals for which they were designed. On-going research indicates they may ameliorate sediment and nutrient losses from agricultural watersheds. In two separate studies, we evaluate relationships between in-stream habitat, water chemistry, spatial distribution, and geomorphic features within a predominantly agricultural watershed in Ohio using Canonical Correspondence Analysis (CCA) and variance partitioning to relate environmental variables to fish and macroinvertebrate community attributes. At 32 sites in the first study, we: (1) identify and quantify key environmental variables; and (2) evaluate the influence of those variables in structuring fish assemblage attributes. Fish communities were explained best by stream size, gradient, and substrate size and quality. Results suggest that measured geomorphology variables and consideration of spatial location of a stream reach within a watershed system sho (open full item for complete abstract)

Committee: Andy Ward (Advisor); Jonathan Witter (Committee Member); Lance Williams (Committee Member); Jay Martin (Committee Member) Subjects: Agricultural Engineering; Aquatic Sciences; Environmental Engineering; Environmental Management; Environmental Studies; Freshwater Ecology; Geomorphology; Hydrology; Sustainability; Water Resource Management