College of Agriculture & Natural Resources
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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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 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 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 SUBAQUEOUS SOILS OF SOUTH RIVER, MARYLAND: SOIL-LANDSCAPE MODEL EVALUATION(2021) Park, Cedric Evan; Rabenhorst, Martin C; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The way soils form, their distribution on the landscape, and their interactions with their ecosystems must be understood if they are to be managed well. Our incipient understanding of subaqueous soils limits successful management, but recent research efforts have sought to address this problem. The goal of this study was to evaluate the protocols for describing, characterizing, classifying, and mapping subaqueous soils. To this end, a subaqueous soil-landscape model (Wessel, 2020) was used to predict the distribution of soils in South River, a western shore Chesapeake Bay subestuary. The soils of South River were surveyed, and the observed soils were compared to the predictions. The model provided significant positive guidance for mapping subaqueous soils, confirming that a pedological approach is useful in subaqueous settings. Pedological data were used to generate a subaqueous soils map for South River and make recommendations to refine the model. Protocols related to soil porewater halinity and mineralogy were also investigated.Item GREEN INFRASTRUCTURE IN INTEGRATED URBAN WATER MANAGEMENT: MODELING AND SOCIAL-ECOLOGICAL SYSTEM APPROACHES(2020) Mosleh, Leila; Pavao-Zuckerman, Mitchell Adam; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urbanization, climate change, increasing water demand, deteriorating water quality, and insufficiencies in system resilience have encouraged city planners to consider integrated urban water management (IUWM) as a solution. One of the main benefits of IUWM is looking into stormwater as a resource to decrease the need for potable water and put less burden on wastewater treatment systems and the environment. Green infrastructure (GI) is an essential part of stormwater management that is designed to mimic the natural hydrological cycle and allows for infiltration, capture and reuse, and treatment of stormwater. This dissertation is designed to inform urban water decision-makers with a special focus on GI via assessment and management frameworks and stakeholder engagement. In my first study, I provided a comparative study of IUWM models aimed at assisting users to select the most appropriate model according to any specific needs. Our results showed that most of IUWM models included stormwater management and GI selection, but do not consider ecosystem services evaluation and the supply and demand from GI. Following these deficiencies of the available models, in my second study, I looked into the stakeholders’ knowledge, perception, and practice of GI with respect to ecosystem services supply and demand. The results showed the study of supply and demand, as well as ecosystem disservices, can help the selection of effective forms of GI to address the priority of stakeholders and environmental issues. Selection of the right type of GI is important for the sustainability of GI in providing ecosystem services, but so is monitoring and evaluation of GI. Thus, my third study focused on developing a generalized social-ecological framework for assessing urban stormwater GI resilience. The results of this study showed that assessing resilience requires linking indicators to critical functionality of GI, as well as a social-ecological approach that goes beyond design and technical specifications. This study can help prioritize resources to address goals related to building resilience. In my last study, I aimed to refine and co-produce a specific social-ecological framework for stormwater GI resilience with stakeholders that links to perceived barriers and challenges of implementing GI. Stakeholders co-created indicators considering current GI challenges and linked them with resilience management dimensions. This framework could inform the management of adverse events and improve resilience by decision-makers and multi-stakeholders in various sectors related to GI planning, design, and implementation.Item Identifying Problematic Hydric Soils Derived from Red Parent Materials in the United States(2018) Mack, Sara Christine; Rabenhorst, Martin C; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Hydric soils derived from some red parent materials are “problematic” to identify during wetland delineations because they resist redox-induced color changes. These (PRPM) soils can be identified using the F21 – Red Parent Material field indicator, but the distribution and cause of the phenomenon, remains uncertain. The objectives of this study were to identify locations where PRPM occurs for appropriate use of the F21 field indicator throughout the country, and to better understand why PRPM soils resist redox-induced color changes. We found that PRPM is associated with sedimentary, hematite-rich, “red bed” formations and the deposits derived from them. Guidance maps have been developed showing where use of F21 is appropriate to support hydric soil (and therefore wetland) delineations impacted by PRPM. We also demonstrated that the cause of PRPM appears to be related to larger crystallite sizes of hematite in PRPM soils.Item Toxicity and Contamination in Bear Creek Sediment: Spatial Analysis and Implications for Risk Assessment(2016) Hartzell, Sharon Hartzell; Yonkos, Lance T; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The sediments of Bear Creek near Baltimore, Maryland demonstrate substantial toxicity to benthic organisms, and contain a complex mixture of organic and inorganic contaminants. The present study maps the spatial extent and depth profile of toxicity and contamination in Bear Creek, and explores correlations between heavy metals, organic contaminants, and toxic responses. Two novel analytical techniques – handheld XRF and an antibody-based PAH biosensor – were applied to samples from the site to quantify total metals and total PAHs in sediments. By comprehensively assessing toxicity in Bear Creek, the present study provides data to inform future risk assessments and management decisions relating for the site, while demonstrating the benefits of applying joint biological assays and chemical assessment methods to sediments with complex contaminant mixtures.Item Advancing Ecosystem Based Fisheries Management: Biological Reference Points for Nutritional Status of Striped Bass (Morone saxatilis)(2014) Haus, William; Harrell, Reginal M; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Nutritional condition is a valuable metric in ecosystem-based fisheries management. However, the need for lethal sampling for the most accurate indicators ethically and logistically limits sample sizes. Percent moisture has been recommended for management of striped bass Morone saxatilis and a management threshold has been suggested. Past researchers have used bioelectrical impedance analysis (BIA) to non-lethally estimate percent dry weight, the inverse of percent moisture. We sought to develop species-specific BIA models for striped bass in a controlled, laboratory setting and later validate those models with independent, field-collected data. BIA models were developed for five size classes and sampled across three temperatures. Results in the lab suggest BIA is an accurate and robust method for estimating percent dry weight in striped bass. However, when implemented in field surveys results are less conclusive. Possible differences between wild and hatchery-reared striped bass that effect BIA need further exploration. Additionally, the effects of salinity and stress response on BIA warrant further work.Item EVALUATION OF BASE LINERS TO REDUCE NITROGEN AND SALT LEACHING FROM POULTRY LITTER STORAGE STOCKPILES TO THE UNDERLYING SOIL - A FIELD COLUMN STUDY(2011) Baranyai, Vitalia; McGrath, Joshua M; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Agriculture has been linked to the eutrophication of the Chesapeake Bay. The Delmarva Peninsula is an intensive poultry producing region, where poultry litter (PL, mix of manure and bedding material) is often stored in outdoor stockpiles. Continued development of management practices is required to achieve environmentally sound PL storage. This study evaluates base liners placed between the bottom of the pile and the soil to reduce nitrogen (N), potassium (K) and sodium (Na) movement from PL stockpiles after 15 and 91 days of storage. Six conically shaped stockpiles were established with five PVC pipe columns placed in the soil under each pile. The soil surface in each column was covered with one of five treatments: alum, gypsum, lime, plastic, or control (no material). Nitrogen, K and Na concentrations increased between 15 and 91 days of storage. Ammonium losses under alum and lime treatment were not different from the control. Alum created adverse conditions by dropping the pH to 3.8. After 91 days of storage, the surface 10 cm of the soil was severely salt affected: under alum, gypsum, lime and control the conditions became moderately to strongly saline. Plastic was most effective in preventing N, K and Na leaching to the soil.Item On-Farm Dry Matter Analysis to Improve Feed Delivery Precision on Dairy Farms(2011) French, Karin R.; Kohn, Richard A; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Uncertainty in dairy ration content impacts feed efficiency, milk production, expenses, and environmental losses. When measuring silage by weight, unknown changes in dry matter (DM) may change the total mixed ration. The objective of this study was to measure variation in silage DM on selected farms and evaluate an electronic method of on-farm DM analysis. Of 31 Maryland farms surveyed, 63% reported DM analysis by an on-farm method, 83% by any method including laboratory measurement. Eight producers performed DM analysis daily for 21 days using a Farmex 1210 Electronic Silage Tester (on-farm) and they recorded precipitation; matching samples were analyzed for DM in a laboratory after oven drying ("standard" method, 55°C followed by 100°C) and by using a Farmex 1210 (laboratory). The standard deviation of mean silage DM varied from 0.72% to 3.33% DM, depending on farm. The electronic method compared poorly to standard DM analysis for most farms.