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Investigating The Spatiotemporal Distribution Of A Tick-Borne Pathogen, Ehrlichia Chaffeensis, Dylan Simpson
Investigating The Spatiotemporal Distribution Of A Tick-Borne Pathogen, Ehrlichia Chaffeensis, Dylan Simpson
Dissertations, Theses, and Masters Projects
The incidence of tick-borne diseases is on the rise in the US and around the world, due in part to emerging pathogens. However, the environmental drivers affecting these pathogens remain unclear. Most research on the topic in the US has focused on Borrelia burgdorferi, which causes Lyme, but it is unknown if the same conditions that affect B. burgdorferi also affect other pathogens, which may be carried by other ticks or reservoirs. The answer will help determine generalizable principles in tick-borne pathogen ecology, if they exist, as well as better manage for tick-borne pathogen risk in areas at risk from …
Shifting Patterns Of Ribbed Mussel Distribution And Ecosystem Services In Response To Sea Level Rise, Robert Earl Isdell
Shifting Patterns Of Ribbed Mussel Distribution And Ecosystem Services In Response To Sea Level Rise, Robert Earl Isdell
Dissertations, Theses, and Masters Projects
Throughout the salt marshes of the US Atlantic Coast, ribbed mussels (Geukensia demissa, Dillwyn, 1817) and smooth cordgrass (Spartina alterniflora Loisel) form an important mutualistic relationship. Spartina provides habitat and promotes settling of ribbed mussels, which, in turn, stabilize and fertilize the Spartina and sediment. This relationship, however, is at risk of interruption due to sea level rise, erosion, and coastal development. Among the most at-risk segments of the marsh, the front (waterward) edge of the marsh is also where ribbed mussels and their ecosystem services are concentrated. Despite their importance of ribbed mussels to the salt …
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Dissertations, Theses, and Masters Projects
Anthropogenically-induced climate change has resulted in increases in water temperature and the frequency and severity of hypoxic events in coastal areas worldwide. Temperature and hypoxia affect fishes' energetics which can, in turn, be reflected in changes in reproductive success and shifts in spatial distributions. in an effort to quantify these changes in Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus) in Chesapeake Bay. I: (1) estimated standard and maximum metabolic rates and hypoxia tolerances at five temperatures (10, 15, 20, 25 and 30°C) using intermittent-flow respirometry, (2) examined the effects of hypoxia exposure on metrics of reproductive potential and, (3) …
Impacts Of Sea Level Rise On Tidal Wetland Extent And Distribution, Molly Mitchell
Impacts Of Sea Level Rise On Tidal Wetland Extent And Distribution, Molly Mitchell
Dissertations, Theses, and Masters Projects
Tidal marshes are a major ecological resource in Virginia and a driver of many estuarine functions. Therefore, the long term sustainability of tidal marsh ecosystems is a question of great interest in the research community. Sea level is rising at an unusually high rate in the Chesapeake Bay relative to most of the Atlantic coastline, putting Bay marshes at high risk from drowning and erosion. Sea level rise-driven salinity changes communities and alters ecosystem services. Understanding the patterns of change and the importance of different drivers of change is critical to tidal marsh sustainability. The overarching goal of this research …
Movements, Habitat Utilization, And Post-Release Survival Of Cobia (Rachycentron Canadum) That Summer In Virginia Waters Determined Using Pop-Up Satellite Archival Tags (Psats), Douglas Jensen
Dissertations, Theses, and Masters Projects
Cobia (Rachycentron canadum) is a cosmopolitan marine fish inhabiting tropical, sub-tropical, and temperate marine and estuarine waters. Recent changes in U.S. cobia management have sparked controversy and highlighted limitations in our understanding of seasonal movement patterns and problems with estimating recreational harvests. Consecutive years (2015 and 2016) of estimated overharvests from the Atlantic Migratory Group stock triggered accountability measures to prevent overfishing by recreational anglers. My project employed pop-up satellite archival tags (PSATs) to study cobia movements, habitat utilization, and post-release survival. It was, therefore, designed to enhance knowledge of cobia biology and aid sustainable management. We deployed 36 PSATs …
Effects Of Anthropogenic Noise On Songbird Social Networks, Carly Elizabeth Hawkins
Effects Of Anthropogenic Noise On Songbird Social Networks, Carly Elizabeth Hawkins
Dissertations, Theses, and Masters Projects
Anthropogenic noise, which is increasing globally, affects birds from gene expression up through alteration of community composition. as urbanization pushes further into undisturbed habitat, noise often disperses birds away from the point source. The impacts of this dispersal on surrounding quieter areas is not well understood. Therefore, in the first chapter, we sought to understand how noise-related dispersal affected the sociality of groups of songbirds as they moved away from the source of noise. as the displaced birds would likely be forced to occupy a smaller area that may already have resident individuals, we predicted that displaced birds would show …
The Role Of Ecological Interactions In Saltmarsh Geomorphic Processes, Bethany Lynn Williams
The Role Of Ecological Interactions In Saltmarsh Geomorphic Processes, Bethany Lynn Williams
Dissertations, Theses, and Masters Projects
Accelerated sea-level rise poses a significant threat to coastal habitats. Salt marshes are critical coastal ecosystems, providing a host of services such as storm protection, food production, and carbon storage. Persistence of salt marshes in the face of rising sea levels relies, in part, on vertical accretion. Current ecogeomorphic models and empirical studies emphasize the importance of the positive relationship between plant production and vertical accretion via sediment trapping by stems aboveground and belowground organic matter production. Thus, changes in plant production influence salt marsh persistence with sea-level rise. However, studies and models of marsh accretion do not consider the …
Carry-Over Effects In Complex Life Cycles: Linking Larval Food Supply With Juvenile Recruitment Success In Sea Stars, Emily Richardson
Carry-Over Effects In Complex Life Cycles: Linking Larval Food Supply With Juvenile Recruitment Success In Sea Stars, Emily Richardson
Dissertations, Theses, and Masters Projects
The supply of new individuals into a population is one of the most important factors impacting species distributions and ecological interactions within a community. For marine invertebrates with complex life cycles, the supply of new individuals into a population can be influenced by factors experienced throughout their life history—before, during, or after metamorphosis. In recent years, scientists have begun to take a more holistic approach to understanding marine population assemblages by considering links between early life stages. When experiences in the pre-metamorphic life stages impact post-metamorphic life stages, this is known as carry-over effects. Because carry-over effects impact fitness of …
Range-Wide Variation In Common Milkweed Traits And Its Effect On Larvae Of The Monarch Butterfly, David De La Mater
Range-Wide Variation In Common Milkweed Traits And Its Effect On Larvae Of The Monarch Butterfly, David De La Mater
Dissertations, Theses, and Masters Projects
Plants play an important role in structuring ecological communities from the bottom up through interactions with herbivores, and environmental variation can affect these interactions. We use the interaction between common milkweed (Asclepias syriaca) and the monarch butterfly (Danaus plexippus) to examine 1) the role of environmental variation in dictating plants traits, and 2) how those variations affect herbivores. We quantified intraspecific trait variation in 53 natural common milkweed populations, then remeasured these traits when population representatives were regrown in a common garden to control for environmental variation. We then measured growth, performance, and survival of monarch larvae feeding on these …