UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Urban Sprawl & Critter Crawl: Imagining a More-Than-Human Way of Living(2024) Islam, Ramisa Maisha; Williams, Brittany; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Over half of the world’s population lives in urban areas and that number is projected to double by 2050. Cities and urban transects have an important role in addressing climate change. As urban population and development grows, we also see a decline in biodiversity. Humans are not the only species being displaced. Native species lose their natural habitats due to development and seek refuge in urban areas. The complexity of cities allows for urban biodiversity to find a home, but these urban habitats are still human centered, forcing species to fit within a human designed environment. This thesis explores the balance between human living and urban biodiversity to integrate into our cities. Implementing urban biodiversity strategies and more than human design in urban neighborhoods can help to restore biodiversity and strengthen human relationships with the natural environment. Combining these concepts can reimagine the city as a shared ecosystem that serves all species. An ideal shared ecosystem can support urban living, embrace coexistence, and foster a symbiotic relationship between humans and nature.Item Understanding Values in Organizational Contexts: The Case of Species Conservation(2021) Dewey, Amanda Michelle Milster; Ray, Rashawn; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Biodiversity loss poses an existential threat to human life, and human activities both intentionally and unintentionally affect other species. Values provide an important tool for explaining such human behavior. While we have evidence of the causes and consequences of wildlife values at the individual level, much human activity that influences wildlife occurs in organizational settings. This project seeks to uncover the roles and negotiation of values in conservation organizations, filling an important research gap. The project uses a case study approach to illuminate the role and negotiation of values in case studies of three wildlife conservation contexts: national wildlife conservation, red wolf conservation, and horseshoe crab conservation in the mid-Atlantic. Through strategic selection of two organizations in each case, I explore how values function in these varied conservation contexts using interviews with staff and volunteers and content analysis of websites and social media. I argue that a broader typology of value frames exists within wildlife conservation organizations than is traditionally discussed in wildlife value literature. I find that frames include moral conservationist, community-steward, and complex utilitarian values, adding nuance to the previously understood value spectrum of humans versus nature. While findings indicated that values were behavior motivators for volunteers, volunteers were more likely to perceive and attempt to construct value alignment than to actively seeking organizations that were compatible with their values. While organizations proclaimed their values and described using values in determining tactics and approaches, they also did not report consciously attempting to align values in processes of volunteer recruitment. Findings indicated differences in value processes in local versus national organizations, and a complex value framing in organizational settings. Despite the fact that the COVID-19 pandemic is an extremely disruptive social event that was directly tied to wildlife and biodiversity issues, this connection was not highlighted equally by volunteers or organizations, nor did organizations equally or significantly respond to a nationwide call to reckon with racial injustice. I argue that the organizations and volunteers who framed their values and approaches more broadly and included moral value of the wellbeing of both humans and other species were more responsive to changing social contexts.Item LONG-TERM IMPACTS OF AMAZON FOREST DEGRADATION ON CARBON STOCKS AND ANIMAL COMMUNITIES: COMBINING SOUND, STRUCTURE, AND SATELLITE DATA(2020) Rappaport, Danielle I; Dubayah, Ralph; Morton, Douglas; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The Amazon forest plays a vital role in the Earth system, yet forest degradation from logging and fire jeopardizes carbon storage and biodiversity conservation along the deforestation frontier. Polices to reduce forest carbon emissions (REDD+) will fall short of their intended goals unless carbon and biodiversity losses from forest degradation can be monitored over time. Emerging remote sensing tools, lidar and ecoacoustics, provide a means to monitor carbon and biodiversity across spatial, temporal, and taxonomic scales to address data gaps on species distributions and time-scales for recovery. This dissertation draws from a novel multi-sensor perspective to characterize the long-term ecological legacy of Amazon forest degradation across a 20,000 km2 landscape in Mato Grosso, Brazil. It combines high-density airborne lidar, 1100 hours of acoustic surveys, and annual time series of Landsat data to pursue three complementary studies. Chapter 2 establishes the bedrock of the investigation by using fine-scale measurements of structure sampled across a large diversity of degraded forests to model the initial loss and time-dependent recovery of carbon stocks and habitat structure following fire and logging. Chapter 3 models the interactions between sound and structure to predict acoustic community variation, and to account for attenuation in dense tropical forests. Lastly, Chapter 4 uses sound to go beyond structure to identify the specific degradation sequences and pseudo-taxa that give rise to variation in the ‘acoustic guild’ over time. Soundscapes reveal strong and sustained shifts in insect assemblages following fire, and a decoupling of biotic and biomass recovery following logging that defy theoretical predictions (Acoustic Niche Hypothesis). The synergies between lidar and acoustic data confirm the long-term legacy of forest degradation on both forest structure and animal communities in frontier Amazon forests. After multiple fires, forests become carbon-poor, habitats become simplified, and animal communication networks became quieter, less connected, and more homogenous. The combined results quantify large potential benefits to protecting already-burned Amazon forests from recurrent fires. This dissertation paves the way for greater integration of remote sensing and analysis tools to enhance capabilities for bringing biomass and biodiversity monitoring to scale. Building on this research with species-level and multi-temporal measurements will reduce uncertainty around the breakpoints that drive carbon and biodiversity loss following degradation.Item Changes in the community structure of urban and rural forest patches in Baltimore from 1998 to 2015(2016) Templeton, Laura Kristine; Sullivan, Joseph; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urban forests are often highly fragmented with many exotic species. Altered disturbance regimes and environmental pollutants influence urban forest vegetation. One of the best ways to understand the impacts of land-use on forest composition is through long-term research. In 1998, the Baltimore Ecosystem Study established eight forest plots to investigate the impacts of urbanization on natural ecosystems. Four plots were located in urban forest patches and four were located in rural forests. In 2015, I revisited these plots to measure abundances and quantify change in forest composition, diversity, and structure. Sapling, shrub, and seedling abundance were reduced in the rural plots. Alpha diversity and turnover was lower in the rural plots. Beta diversity was reduced in the rural plots. The structure of the urban plots was mostly unchanged, except for a highly reduced sapling layer. Beta diversity in the urban plots was consistent across surveys due to high species turnover.Item The Diversity of Burrowing Benthic Invertebrates and their Impact on Phosphorus Dynamics in Agricultural Drainage Ditches(2014) Leslie, Alan William; Lamp, William O; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Agriculture remains the most widespread cause of impairment of freshwater habitats, but farm lands with artificial drainage structures such as ditches have specific locations where natural physical and biogeochemical processes can be used to reduce nutrients delivered to local watersheds. Agricultural drainage ditches can also be sources of biodiversity, serving as patches of uncropped aquatic habitat that may provide a significant amount of diversity to agricultural landscapes. Macroinvertebrate communities play important roles in nutrient cycling in natural aquatic ecosystems, but to this date no information exists on the role of invertebrate communities in biogeochemical processes occurring in ditches. The overall goal of my dissertation was to determine the structure of the aquatic macroinvertebrate community of agricultural drainage ditches, and to determine the functions these species play in nutrient cycling. First, I performed a broad survey of aquatic macroinvertebrates in drainage ditches and related the community composition to environmental conditions. Ditches support different communities of macroinvertebrates, and community composition is correlated with physical habitat characteristics such as flow velocity (r2=0.58) and ditch size (r2=0.56), rather than water quality. I then measured the burrowing community of small (field) and large (collection) ditches over a year to determine how size class and seasonality affect taxonomic and functional group composition. I found small and large ditches support different taxa due to the intermittent water condition of small ditches, but both types of ditches support similar functional groups. There is limited diversity among functional feeding groups in ditches, but the majority of macroinvertebrates (101 of 140 taxa) are benthic taxa that may cause bioturbation of ditch sediments. I used microcosms to measure the effect that different burrowing species (Ilyodrilus templetoni, Limnodrilus hoffmeisteri, Crangonyx sp., Chironomus decorus S.G.) have on phosphorus dynamics between ditch sediments and water. Results show different species can increase (0.28 to 2.05 mg/L) or decrease (0.08 to 0.41 mg/L) soluble, reactive phosphorus concentrations in surface water, depending on the type of burrowing and environmental conditions. Different types of burrowers likely alter phosphorus dynamics through different mechanisms, and increasing diversity of burrowers could have non-additive effects on phosphorus uptake by ditch sediments.Item The Influence of Predator Species Richness on Prey Mortality: Implications to Conservation Biological Control.(2006-12-04) Lewins, Scott Asher; Barbosa, Pedro; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Understanding how changes in biodiversity affect the function of agroecosystems is paramount to conservation biological control. The Species Assemblage Control Hypothesis predicts increasing species richness of predator assemblages can increase the assemblages' ability to suppress pests. I hypothesized that an increase in species richness of a predator assemblage leads to an increase in prey mortality and predator species identity can alter the relationship. An assemblage of predators identified from an assessment of a collard agroecosystem was evaluated to find that only some predators fed on larval Pieris rapae, they did not differ in their per capita consumption, and some intraguild predation occurred. In testing the hypotheses I found a significant relationship between predator species richness and prey mortality; however, predator species identity altered the relationship. These findings highlight the importance in understanding predator assemblages before conservation decisions that effectively suppress pests can be made.