Biology
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Item UNDERSTANDING MANAGED RETREAT THROUGH A MULTI-STAKEHOLDER LENS: A CASE STUDY ON THE LOWER EASTERN SHORE OF MARYLAND(2021) Miralles, Andrea Maria; Paolisso, Michael J.; Alcañiz, Isabella; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Due to concerns about increasing sea levels and climate displacement, there has been a growing interest in the adaptation option of managed retreat. In managed retreat, shorelines move inland acting as a natural buffer to coastal climate impacts, while coastal communities move to higher ground through voluntary home buyouts. Managed retreat is also highly controversial, as it is poorly understood and presents significant challenges to equity. In order to address these issues, this thesis research provides a multi-stakeholder analysis on the Lower Eastern Shore of Maryland focused on understandings and trust in managed retreat processes. Key findings from this research are that communities, government and non-governmental organizations have different understandings of managed retreat, that retreat discussions need to occur at official levels now, that equity must be a central component of planning, that trust is necessary for successful retreat and that any future retreat must emphasize community agency and collaboration.Item EFFECTS OF SEA LEVEL RISE ON TIDAL FRESHWATER, OLIGOHALINE, AND BRACKISH MARSHES: ACCRETION, NUTRIENT BURIAL, AND BIOGEOCHEMICAL PROCESSES(2019) Allen, Jenny; Baldwin, Andrew H; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Tidal wetlands provide critically important ecosystem services such as storm surge and flood attenuation, pollution retention and transformation, and carbon sequestration. The ability of tidal wetlands to maintain surface elevation under accelerated sea level rise is critical for their persistence. Saltwater intrusion can further threaten tidal freshwater marshes by decreasing primary production and organic matter accumulation as well as cause shifts in microbial pathways, leading to increases in organic matter decomposition and an overall decrease in marsh elevation. The objectives of this research were to examine accretion dynamics across the estuarine gradient of the Nanticoke River, a major tributary of the Chesapeake Bay, and determine the relative contribution of organic and inorganic matter to accretion in the marshes; determine the accumulation rates of C, N, and P across the estuarine gradient; and examine the effects of sulfate intrusion on biogeochemical transformations and marsh surface elevation in tidal freshwater marsh soil. Results of the collective studies suggest that the mechanisms controlling accretion dynamics and nutrient accumulation are complex and are likely driven by site-specific factors rather than estuary-wide factors. Accretion rates and nutrient accumulation rates were highly variable across the estuarine gradient, but were largely dependent on both organic matter accumulation and inorganic sedimentation. Only 8 out of the 15 subsites had accretion rates higher than relative sea level rise for the area, with the lowest rates of accretion found in the oligohaline marshes. Organic matter accumulation is especially important in marshes with low mineral sediment supply, particularly mid-estuarine oligohaline marshes, but may not be enough to help keep these marshes above relative sea level. The tidal marshes along the Nanticoke River removed approximately 15% and 9% of the total N and P load entering the system, but their ability to continue to remove nutrients may be compromised due to rising sea levels. Shifts in microbial pathways and increases in organic matter decomposition due to saltwater intrusion further threaten the ability of these marshes to keep pace with sea level rise, potentially resulting in the loss of an extremely valuable ecosystem.Item Effects of Sea Level Rise on Tidal Marshes(2014) Bryan, Jennifer; Harris, Lora; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)There is growing concern regarding the potentially negative impacts of sea level rise (SLR) on tidal wetlands in the Mid-Atlantic region of the United States. In Chapter one, I investigate the phenotypic plasticity and biomechanical properties of Zizania aquatica under experimental inundation treatments. At lower elevations and higher inundation designed to simulate SLR, Zizania aquatica did indeed respond with phenotypic changes such as increased height and stem thickness, and decreased stem density, areal aboveground biomass, and modulus of elasticity. In Chapter two, I investigate the nitrogen removal role of Chesapeake Bay tidal wetlands under current and simulated long-term SLR. I also examine nitrogen removal at smaller scales in Maryland, comparing restoration goals for nitrogen loading reductions with the loss of nitrogen removal services expected by 2025. Tidal wetlands are expected to decrease in the Bay and Maryland and associated loss of nitrogen removal services may affect attainment of restoration goals.