Theses and Dissertations from UMD
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Item INDIGENOUS INVOLVEMENT IN ECOLOGICAL RESTORATION: AN ANALYSIS OF VIRGINIA’S SOVEREIGN NATIONS INVOLVEMENT IN THE CHESAPEAKE BAY PROGRAM(2023) Brooks, Nicole L; Shaffer, L. J.; Rose, Kenneth A.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Indigenous involvement in conservation and restoration practices, specifically those funded by government entities (e.g., EPA, USGS, NOAA), is not well documented in the Mid-Atlantic region of the United States. Increased Indigenous involvement in conservation and restoration projects globally, raises questions regarding this apparent environmental practice gap in the Eastern United States (McAlvay, 2021; Poto, 2021; Turner, 2010). Currently, government-led restoration projects in the Chesapeake Bay, led by the Chesapeake Bay Program, lack a strong Indigenous presence or contribution despite 7 federally-recognized Sovereign Nations in the surrounding watershed. To understand this gap, a literature review was first conducted to provide an initial context for viewing the contemporary Indigenous involvement in Chesapeake Bay restoration. The review was the basis for a detailed analysis of Virginia’s Sovereign Nation involvement in the Chesapeake Bay Program that used a series of interviews, participant observations, and a social network analysis. Interview participants were classified into one of three representative categories: Sovereign Nation, government organization, and non-government organization. Questions about working relationships between organizations were assessed to understand the political-ecological dynamics driving the interactions in the Chesapeake Bay restoration social network, specifically among the representative categories. Results showed a lack of a consistent and intentional relationship between the Sovereign Nations of Virginia and the Chesapeake Bay Program. According to the federal trust relationship, this infers that the lack of a strong Sovereign Nation involvement in the Chesapeake Bay Program may be contributing to a continued state of Environmental Injustice. To begin to address this low-level of involvement, the Chesapeake Bay Program should devote significant effort to building intentional relationships with the Sovereign Nations, including a more formal and official representation within the Chesapeake Bay Program.Item Elucidating factors to improve biological control of Halyomorpha halys by egg parasitoids(2023) Potter, Madeline Elizabeth; Shrewsbury, Paula M; Burghardt, Karin T; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Halyomorpha halys Stål (Hemiptera: Pentatomidae), also known as the brown marmorated stink bug, is an invasive species from Northeast Asia, which has now spread to 47 USA states and invaded several other countries. In the USA, H. halys is an economically important pest of fruit, vegetable, field, and nut crops, and it feeds on ornamental plants. A sustainable means of controlling this pest is needed. Here I focus on elucidating features from bottom-up forces (alternate host identity, host plant identity, and habitat type) which may influence top-down forces such as parasitism by H. haly’s key natural enemies, Hymenoptera egg parasitoids. Naturally laid eggs of insects were collected from a tree nursery in 2020 and from diverse habitats throughout Maryland in 2021 to investigate H. halys parasitoids’ alternate insect egg hosts, host plant and habitat associations, and which factor(s) (host plant identity and/or host egg identity) are important to egg mass discovery, or to egg parasitism rate. Effects of host insect feeding guild (herbivore vs predator) and host plant origin (native vs non-native) on parasitism were also examined. One new overwintering insect host and four new in season hosts for Anastatus spp., and five new in season hosts for Telenomus cristatus were found. A diverse array of plant species, particularly native Acer and Quercus species, were found to support alternate host insects. Halyomorpha halys related parasitoids were reared from eggs collected in all habitat types. Host egg order and egg feeding guild affected Anastatus spp. egg unit discovery efficiency and egg parasitism rate. Host plant identity and plant origin affected egg unit discovery efficiency and egg parasitism rate by all H. halys parasitoids. These findings support the importance of having a diverse community of alternate prey and informed plant selections to support parasitoids and their biological control of H. halys and other insect pests.Item Characterizing nutrient budgets on and beyond farms for sustainable nutrient management(2023) Zou, Tan; Zhang, Xin; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The production and security of food are heavily reliant on adequate nitrogen (N) and phosphorus (P) inputs in agriculture. However, ineffective management of N and P from the farm to the table can result in nutrient pollution, triggering both environmental and social issues. Moreover, another important challenge for P management is limited and unevenly distributed P resources, leading to P scarcity in many parts of the world. Inefficient use of nutrients in agriculture-food systems is the root cause of both nutrient pollution and scarcity. To improve nutrient use efficiency and reduce nutrient loss, it is crucial to address key knowledge gaps in nutrient management research, which include inadequate quantification of nutrient budgets, as well as identifying and addressing nutrient management challenges across various systems and spatial scales. This dissertation tackles the knowledge gaps in two studies, including a global-scale study and a case study of the Chesapeake Bay watershed. In the global-scale study, I establish and utilize a unique P budget database to assess historical P budget and usage patterns at the national and crop type level from 1961 to 2019. This analysis reveals the impacts of various agricultural and socioeconomic drivers on cropland P use efficiency (PUE), including N use efficiency (NUE), fertilizer-to-crop-price ratio, farm size, crop mix, and agricultural machinery. The findings indicate that P management challenges vary by country and spatial scale, necessitating tailored country-level strategies. The regional-scale study applies a framework adapted from N studies to the Chesapeake Bay watershed, analyzing nutrient (N and P) management across systems and spatial scales. This approach uncovers that nutrient loss potential beyond crop farms is larger than that at crop farms. This highlights the need to enhance nutrient management and curb nutrient loss in animal production, food processing and retail, and human consumption. This study also identifies a large potential for meeting cropland nutrient demand by increasing the recycling of nutrients in manure, food waste, and human waste. To tackle the challenges surrounding nutrient management in the watershed, it is imperative to target factors significantly related to nutrient management, such as agricultural practices, soil properties, climate change, and socioeconomic conditions. This dissertation contributes to a deeper understanding of N and P management challenges, gaps, priorities, hidden drivers, and potential solutions at various scales, from regional to national and global levels. The analytical procedures and statistical tools developed in this dissertation are generalizable, allowing for their adaptation to similar nutrient management studies in different regions and for diverse research purposes.Item Social-Ecological Processes and Dynamics of Urban Forests as Green Stormwater Infrastructure in Maryland, USA(2023) Ponte, Sarah; Pavao-Zuckerman, Mitchell A; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urban trees are part of social-ecological systems shaped by the interactions between human components (e.g., communities, management practices, and sociodemographic characteristics) and ecological components (e.g., trees, microclimate, and soil). This dissertation investigated the social-ecological factors that shape urban trees and forest outcomes. Urban trees can reduce stormwater runoff, mitigate flood risk, increase infiltration and water storage capacity in the soil, reduce nutrient loading, and improve water quality in developed areas. This dissertation begins by quantifying the influence of management context (single vs. clustered vs. closed canopy trees) on the transpiration of red maple (Acer rubrum L.), sweetgum (L. styraciflua L), and tulip poplar (L. tulipifera L.) trees as well as the relationship between tree transpiration and environmental drivers (vapor pressure deficit and soil moisture) in Baltimore and Montgomery County, MD. Results showed significantly lower transpiration rates in closed-canopy trees when compared to solitary trees. No significant differences were observed between transpiration rates across tree species in the closed canopy site during the growing seasons of 2018 and 2019. However, species differences in sap flux density were observed at the 24-h time-scale with tulip poplar trees being the most sensitive to drought. In addition to the ecological characteristics of urban forests, it is necessary to take into consideration the human factors and the resulting outcomes (e.g., tree canopy cover and green stormwater infrastructure distribution) for a better understanding of such complex social-ecological systems. Using regression models, spatial patterns and relationships between biophysical, social, and built components were explored at the neighborhood scale in Baltimore, MD. Results showed that the presence of voluntary green stormwater infrastructure (GSI) was positively associated with stewardship activity related to GSI. Median household income and race were significantly associated with the presence of regulatory GSI, and percent impervious cover was a significant predictor for the presence of voluntary GSI. The findings from this dissertation can aid the development and refining of stormwater crediting programs as urban trees can be more accurately incorporated into planning efforts. This dissertation also provides insights on how environmental stewardship and socio-demographics relate to landscape characteristics and informs future research directions regarding social-ecological systems.Item VALUING SHALLOW WATER SYSTEMS IN MARYLAND'S CHESAPEAKE BAY(2022) Munkacsy, Megan; Wainger, Lisa; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Oyster aquaculture (OA) activity is sometimes framed as a hindrance to habitat, recreation, property values, and wild oyster harvest in Maryland’s Chesapeake Bay. Yet, tradeoffs under OA policies have not been thoroughly analyzed. I applied decision science techniques to capture alternative OA policy effects on users and ecosystem services. Stakeholders helped organize system complexities into management goals and performance indicators and shared preferences to inform indicator weights. These weights were applied to outcomes from a suite of economic and ecological models, resulting in each scenario’s stakeholder-weighted summary score. Results revealed that (1) highly protective habitat policies create a risk to future OA production while protecting less than 0.1% of habitat, (2) proposed changes to current OA policies appear less effective at balancing goals, and (3) under no policy does OA impact more than 1.3% of wild oyster revenues. This analysis served to clarify system complexities to inform policy analysis.Item APPLIED STASIS THEORY AND Q-SORTING FOR ORGANIZING ENVIRONMENTAL SCIENCE COLLABORATION FOR POLICY DELIBERATION: A CASE OF POULTRY HOUSE EMISSIONS—AMMONIA AND PARTICULATE MATTER—ON THE DELMARVA PENINSULA/EASTERN SHORE(2022) Shea, Mary E; Tjaden, Robert; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)CONTEXT: Poultry farmers respond to national and global demand for low cost, packaged chicken. Raising poultry for market results in ammonia and poultry litter (manure and dust). However, for the Delmarva part of the Chesapeake Bay Watershed and Airsheds, ammonia and poultry litter mean nitrogen pollution, which effects water quality and human health. Therefore, this inquiry looks closely at the values and benefits that shape poultry farmer decisions about managing ammonia from their poultry houses using two technologies: Vegetated Emissions Buffers (VEBs) and Poultry Litter Treatments (PLTs). QUESTION: How can we better understand the values and benefits embodied in ammonia management choices by poultry farmers? METHODS: This dissertation uses three methods to engage with poultry farmers (2012-19) to better understand a range of values—economic and non-economic—about voluntary ammonia management strategies. 1. Stasis theory (Chapter Two), 2. Scaling of conceptual diagrams to three inch by four-inch cards, for designing visual Q-cards (Chapter Three), 3. Q-sorting of cards and findings (Chapter Four). FINDINGS: The Q-sorting events in this November 2019 study (25 value/benefits statements, sorted with 13 poultry producers) did not meet respondent number thresholds for formal Q-method factor analysis. However, results were studied using exploratory data analysis and chi-square testing of Q-sorting data. One important finding is that these eight cards appeared as important in two analysis categories: first, six cards likely MOST IMPORTANT (Photo 1); and second, the next two cards (Photo 2) as perhaps SOMEWHAT IMPORTANT. These pictured two sets of cards are ranked overall as having greater importance to poultry farmers, compared to aggregate card rankings of the other 17 cards in the 25-member card set. Photo 1: In the aggregate, these six cards were sorted most often into the MOST IMPORTANT category. Photo 2: In the aggregate, these two cards were sorted most often into the IMPORTANT category. The six cards in Photo 1 (MOST IMPORTANT) can be understood in several ways. First, these three cards (position noted in bold) represent economic benefits to poultry farmers, important for farm fiscal stability. The three cards on the left all represent health gains for chickens, meaning a better payout when healthy, unblemished, full-weight birds are sold to the poultry company:• Top-left card: This card symbolizes healthy chickens as “happy”—a visual shorthand for healthy—commanding more per pound at payout. • Middle-left card: This card shows reduced in-house ammonia, which means that chicken flesh is less likely to be burned or marred by ammonia, commanding more per pound at payout; generally, lowered in-house ammonia also means healthier birds, which is a specific value noted in just above in the top-left card description. • Bottom-left card: This card shows unblemished chicken “paws” which can command an extra premium for Asian specialty food markets. This portion of the bird represents a newer market for poultry producers. Within this group, two of these cards in Photo 1 (top- and middle-left) also show the value to farmers of using an enhanced schedule of PLTs to reduce ammonia inside the poultry house. The right-hand cards in Photo 1 can be understood thusly as relying on VEB use:• Top-right card: This card shows energy savings from using VEBs to shade poultry houses and provide winter wind cover, thereby reducing energy costs annually, supporting farm fiscal status. • Middle-right card: This card symbolizes reduced ammonia odor by VEB capture, which can help avoid neighbor and nuisance complaints. • Bottom-right card: This card shows the value of VEBs as helping the farmer meet existing nutrient management planning, a state-administered requirement for many poultry farmers. nitrogen and phosphorus are two nutrients associated with poultry production, poultry litter storage/composting, and poultry litter application as field fertilizer. These three VEB-focused cards in Photo 1 share the common context of concerning ammonia management strategies outside the poultry house, relying on the pollution remediation strategies of VEBs, a type of designed hedgerow plant structure._____ The two cards in Photo 2, noted as IMPORTANT but not as MOST IMPORTANT as the six cards in Photo 1 just described, relate to farmer concerns about human health. • Top card: This card show that poultry farmers can use VEBs outside poultry houses to capture ammonia and particle pollution, thereby improving local air quality, especially for farm families who live close to their poultry houses. • Bottom card: This card show that poultry farmers can use enhanced PLTs to reduce in-house ammonia, thereby improving worker conditions inside the poultry house. CONCLUSION: This case study demonstrates the value of Q-sorting used with Delmarva poultry farmers and attitudes about ammonia management. These findings can be also understood as ground-truthing evidence, in that the visual card-sorting data confirm as important the eight cards discussed above. These values/benefits depicted on these cards fit the poultry context of the Chesapeake Bay ecosystem. Additional Q-sorting activities with these cards or revised card sets to meet research needs are worthy undertakings. This dissertation case study also shows the value of humanities within environmental policy deliberation. Stasis theory, from rhetorical studies, helped organize the complexity of this project, as well as made a clear role for valuing activities (including Q-sorting). A second field of humanities inquiry is science visualization studies. This field, closely allied with rhetoric, helped with design values to build clear and environmentally-situated picture cards for Q-sorting the ranked importance of these cards to poultry farmers. Finally, the last chapter reflects on ways that a human dimensions approach supports a re-imagined Delmarva poultry production. One central design criterion about poultry production futures centers the role of poultry farmers, especially young farmers, in planning for resiliency. Among the pressures on poultry production is the well-documented wetter and warmer Delmarva, to climate change. The COVID-19 pandemic due to the 2019 emergence of the SARS-CoV-2 virus, also posed risks to Delmarva poultry resiliency. Scenario analysis and design options are better with humanist and social science knowledge, combined with environmental science.Item Monitoring and Predicting the Microbial Water Quality in Irrigation Ponds(2022) Stocker, Matthew Daniel; Hill, Robert L; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Small- to medium-sized farm ponds are a popular source of irrigation water and provide a substantial volume of water for crop growth in the United States. The microbial quality of irrigation waters is assessed by measuring concentrations of the fecal indicator bacteria Escherichia coli (E. coli). Minimal guidance currently exists on the use of surface irrigation waters to minimize consumer health risks. The overall objective of this work was to provide science-based guidance for microbial water quality monitoring of irrigation ponds. Spatial and temporal patterns of E. coli were evaluated in two Maryland irrigation ponds over three years of observations. Patterns of E. coli were stable over the three years and found to be significantly correlated to patterns of water parameters such as temperature, dissolved oxygen, turbidity, and pH. The EPA Environmental Fluid Dynamics Code model was used to evaluate the spatial 3D heterogeneity of E. coli concentrations within the ponds. Significant differences in E. coli concentrations by sampling depth were found. Spatial heterogeneity of E. coli within the pond also resulted in substantial temporal variation at the irrigation pump, which was dependent on the intake location. Diurnal variation of E. coli concentrations was assessed for three farm ponds. E. coli concentrations declined from 9:00 to 15:00 for each pond, but statistically significant declines were only observed in two of the three ponds. Dissolved oxygen, pH, and electrical conductance were found to be the most influential environmental variables affecting E. coli concentrations. To better describe the relationships between E. coli and the environmental variables, four machine learning algorithms were used to estimate E. coli concentrations using water quality parameters as predictors. The random forest algorithm provided the highest predictive accuracy with R2 = 0.750 and R2 = 0.745 for Ponds 1 and 2, respectively, in the multi-year dataset containing 12 predictors. Temperature, electrical conductance, and organic matter content were identified as the most influential predictors. It is anticipated that the recommendations contained in this dissertation will be used to improve microbial monitoring strategies and protect public health.Item Using citizen science to collaboratively research and manage Chesapeake Bay(2021) Webster, Suzanne E; Dennison, William C; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Chesapeake Bay is a complex socio-ecological system with an equally complex adaptive management program. The environmental management community has expressed a need for more local-scale environmental data and increased stakeholder engagement in Bay restoration efforts. Although citizen science has the capacity to meet both of these needs, participatory research is currently underused and undervalued. Additional research is needed to help Chesapeake Bay environmental stakeholders develop and leverage citizen science partnerships to accomplish diverse research and management goals. This dissertation explored various challenges that limit the use and potential impact of citizen science in Chesapeake Bay. Three distinct studies were conducted to gain a more complete understanding of stakeholders’ perceptions and experiences concerning public engagement in scientific research. These studies employed several qualitative and quantitative approaches, including interviews, participant observation, surveys, and cultural consensus analysis. This research provided evidence of widespread agreement that diverse stakeholder concerns should be more prominent in management decisions. Research also found shared feelings of disempowerment across the Chesapeake environmental community. Environmental stakeholders appreciated that science plays a central role in informing environmental policy, but they had mixed perspectives on the utility of citizen science. This research found an underlying cultural understanding of environmental monitoring that provides a foundation for collaboration among stakeholders with different priorities. These findings indicate that citizen science programs can a) serve as boundary spanning organizations that help stakeholders foster a more cooperative mentality, b) allow diverse groups to strategically work together to accomplish goals, and c) increase the impact of volunteer-collected data on Chesapeake science and management. This research also showed that using a transdisciplinary approach to citizen science can increase stakeholders’ feelings of engagement, improve perceptions of a program’s overall credibility, and increase the program’s overall likelihood for impact. The results of this place-based study in the Chesapeake region are also broadly applicable to other socio-environmental systems. This dissertation provides evidence-based support for continued and expanded stakeholder engagement in environmental science and management and offers specific recommendations to support more collaborative, productive, and empowering citizen science partnerships that inform holistic and innovative environmental management decisions.Item NUTRIENT RETENTION BY RIPARIAN FORESTED BUFFERS IN WESTERN MARYLAND: DO THEY WORK AND ARE THEY WORTH IT?(2021) Siemek, Stephanie Melissa; Eshleman, Keith N; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Riparian buffers are a best management practice (BMP) implemented to improve water quality. In 1997, Maryland established the Conservation Reserve Enhancement Program (CREP) to give landowners incentives to install riparian buffers that would help restore the Chesapeake Bay. Although many studies support riparian buffers as a BMP, many have also reported a wide range of nutrient reductions. It is uncertain what factors control buffer function, yet they continue to be installed with high expectations. Water quality predictions become less accurate in hydrogeologically complex systems such as the Ridge and Valley (R&V) physiographic province. The purpose of this research was to assess the riparian buffer’s nutrient removal function of dissolved nitrogen and phosphorus in the R&V to understand the hydrologic controls further. Throughout western Maryland, we conducted two synoptic stream chemistry studies that contained forest buffers planted under CREP and a range of pre-existing natural forested riparian zones. We used a steady-state reach mass balance model to estimate lateral groundwater inputs and tested several nutrient models to describe the nutrients in groundwater discharge. We then aimed to understand if incentives given through CREP to landowners were adequate by performing a benefit-cost analysis (BCA) using three scenarios. We used the BCA results to estimate nutrient reduction costs using results from the Chesapeake Bay Watershed Model (CBWM) and our synoptic studies. Streams along CREP sites did not show strong evidence of nutrient retention. However, those containing a mix of natural forests with planted buffers showed significant nutrient declines in both synoptic studies. Several models tested (i.e., The Nature Conservancy model, Gburek and Folmar (1999), our base model) inadequately described nutrient discharge; however, our actual flow model performed best. Our BCA results found newly planted forest buffers under CREP provide the greatest financial gains to landowners, but grass buffers are the most cost-effective practice based on CBWM’s estimated nutrient reductions. Although our research did not assess grass buffers, our synoptic studies showed little indication that newly planted forest buffers significantly reduce nutrients in the R&V, suggesting stream water quality greatly depends on the watershed’s hydrogeomorphology that controls how major contributing sources filter through the landscape.Item Nutrients, chlorophyll, and emergent harmful algal bloom species of concern in coastal waters of Assateague Island National Seashore(2021) Ross, Morgan O; O'Neil, Judith M; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The Atlantic Ocean coastal zone of Maryland is important both ecologically and economically. Due to water quality issues, the coastal lagoons of Maryland have received considerable research attention, but little corresponding research in the coastal waters that exchange with the coastal lagoons. To better understand the linkages between the coastal ocean and the potential impacts of human activity on Maryland’s coastal zone, 5 research cruises (2018-2019) were completed to investigate concentrations of nutrients and emergent harmful algal bloom (HAB) species of concern (Dinophysis, Karenia, Pseudo-nitzschia). Nutrient and HAB species had high intra-annual variability, as well as geographic variability with relation to the inlets, coastal lagoons, and offshore discharge sites. The most significant determinants across all sampling locations, depths, and times were nitrate and ammonium. Continued eutrophication and climate change, as well as the impact of connected waterways, presents challenges for managing regional water quality issues in the coastal ocean.