Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
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 give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
Browse
12 results
Search Results
Item SMALL MAMMAL POPULATIONS, TICKS, AND TICK-BORNE DISEASES IN URBAN PARKS(2024) Coriell, Carson; Mullinax, Jennifer; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As urban environments expand, the distribution of wildlife, particularly white-footed mice, influences public health through zoonotic pathogen transmission, such as Lyme disease. This study examined pathogen risk in urban green spaces, focusing on interactions among small mammal communities, black-legged ticks, and the bacterium Borreliella (Borrelia) burgdorferi. Over two years, small mammal trapping was conducted across six urban park sites in Maryland to 1) quantify small mammal densities in six unique urban sites and 2) identify correlations between small mammal community and habitat structure related to pathogen prevalence. Findings revealed significant differences in pathogen risk between parks, driven by elevation and landscape features, with open shrub-scrub, and upland habitats, such as powerline corridors, linked to increased transmission risk. These results underscore the importance of habitat-level management strategies for urban green spaces to mitigate pathogen risk, rather than focusing solely on white-footed mice.Item THE EFFECTS OF HISTORICAL AND CURRENT LAND USE ON THE HABITAT USE AND COMMUNITIES OF URBAN WILDLIFE IN THE WASHINGTON, D.C. METROPOLITAN AREA(2024) Collins, Merri Kathleen; Gallo, Travis; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Understanding past legacies of urban land use is important to identify ecological processes and inform best management practices for wildlife-friendly cities in the future. My first dissertation chapter is an overview of my personal research philosophy and how it relates to this dissertation. The second chapter is a systematic literature review that addresses the state of global urban wildlife research. Urban wildlife research is predominantly conducted in North America, Europe, and Australia by academic researchers, and less so in the Global South. The third chapter explores how a gregarious species, the Eastern wild turkey (Meleagris gallopavo silvestris) once extant from the Washinton, D.C. landscape, is making a comeback. Wild turkey had a higher probability of occupying sites further from roads and at lower elevations. The fourth and concluding chapter looks at historic neighborhood valuation in Washington, D.C. to identify any legacy effects of racist and discriminatory urban planning on mammal communities. While I did not find any relationship, I did find similar mammal communities across the city regardless of neighborhood categorization and I derive management implications from this information.Item EVALUATING RELATIONSHIPS BETWEEN BATS AND LANDSCAPE CHARACTERISTICS IN A WHITE-NOSE SYNDROME POSITIVE REGION: DOES URBANIZATION PLAY AN IMPORTANT ROLE?(2021) Browne, Shannon P.; Mullinax, Jennifer M.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)White-nose Syndrome (WNS) is a cascading disease process, initiated by a skin fungus, killing most cave bat populations across North America. WNS severity differs with the ecology of both the pathogen and the bat species host. This study aimed to identify the habitat features most related to cave bat species by surveying cave bats and habitat features across the urban-rural gradient in Maryland. Our understanding of cave bat ecology in Maryland has changed recently due to technological advancements, though prominent gaps still exist in the urbanized Piedmont and Coastal Plain provinces. As such, a novel urban definition was created to allow research sites to well represent each level of the gradient, and sites were surveyed in random order during four seasons from 2015 to 2017. We found unique results when analyzing predator-prey correlations at weekly scales as well as nightly generalized linear mixed models (GLMM) of habitat usage. At both temporal scales, big brown (Eptesicus fuscus) and tri-colored bat (Perimyotis subflavus) activity were higher at urban than suburban sites. While analyzing predatory-prey correlations at the weekly level, big brown bat activity was highly related to their preferred prey counts at urban sites, while tri-colored bat activity correlated to their preferred prey counts at rural sites. Tri-colored bat activity also occurred at sites during seasons that supported less activity by big brown bats. When analyzing habitat features at the nightly level using GLMMs, in suburbia, big brown bat activity appeared most related to their preferred prey and taller trees. Meanwhile, tri-colored bat activity still held a strong relationship with prey at rural sites across multiple seasons. Big brown bats may select suburbia for roosting and foraging while tri-colored bats may select rural settings for foraging. Interestingly, prey were most abundant at rural sites, indicating rural settings may support higher habitat quality along the gradient. Possible reasons for the seemingly spatial and temporal partitioning by these two species included differing resource availability and some form of niche partitioning. Repeated acoustic surveys and telemetry studies across spatial and temporal scales are recommended to aid bats in greatest need during WNS.Item Radiotracking and The Spatial Anaylsis of White-footed Mice (Peromyscus leucopus), in Suburban Maryland Parks.(2020) Hummell, Grace; Mullinax, Jennifer M; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Tick-borne disease transmission has been steadily increasing in the United States. This is a major concern in suburban and urban areas, where wildlife and humans frequently share space. White-footed mice (Peromyscus leucopus) are studied for their role as a host for ticks and a reservoir tick-borne disease. New advances in the ability to track mice give much-needed insight into their space use and the use and efficiency of baited tick treatments. The major objectives of this thesis were to: 1) document suburban mouse collaring, tracking, and comparisons of three available triangulation programs and 2) calculate basic population demographics, home ranges, movement patterns, and land use of mice in three parks in Howard County, Maryland. The applied goal of this research was to aid in the future management of mice and tick-borne diseases as it pertains to the best placement for baited treatment.Item TIME IS ENERGY: DRIVERS OF MIGRATORY AND NON-MIGRATORY MOVEMENTS BY SOARING BIRDS(2020) Mallon, Julie Marie; Fagan, William F; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Vultures are obligate scavengers and search over large areas for carrion, which is ephemeral. To profit from carrion, they are also obligate soarers that rely on the availability of environmental updrafts to subsidize flight. This restricts their flight spatially and temporally to where and when strong updrafts are available. In this dissertation, I investigate how Turkey Vultures (Cathartes aura) use stopovers to both avoid inclement weather and to replenish spent fuel reserves, as well as how the timing of movement activity differs according to flight mode.Using GPS-tracking data from four migratory Turkey Vulture populations, I evaluated how Turkey Vultures respond to changing weather conditions. During stopovers, movement activity was positively correlated with conditions that promote thermal development, suggesting not all stopovers are used for weather-avoidance. Turkey Vultures began stopovers immediately in response to deteriorating weather conditions but their departure from stopovers was delayed relative to improvements in weather, behavior that is consistent with an energy-minimization strategy. I estimated total energetic costs for each migration and identify probable refueling stopovers. Only long-distance Turkey Vulture migrants regularly stop to feed. Overall migratory costs are driven by migration duration, and therefore are lower in the spring when vultures migrate faster, which may contribute to seasonal differences in flight behavior. Last, I compared the non-migratory movements of 49 avian species to test for the influence of flight mode on the timing of movement activity. Terrestrial soaring birds began activity later and stopped activity earlier than other birds. This study demonstrates that flight mode influences temporal patterns of daily movement activity of birds. This dissertation enhances our understanding of how soaring birds cope with the temporal and spatial restrictions on their movements. During non-migration, soaring birds are active for longer proportions of the day to search for food over greater spatial areas than flapping birds. During migration, total energetic costs are driven more by migration duration than by behavior. Therefore, an energy minimization strategy for Turkey Vultures is also a time minimization strategy and vultures are expected to optimize their migration so that they spend the fewest days migrating as possible.Item YOUNG FOREST MANAGEMENT FOR SENSITIVE BIRD SPECIES IN WESTERN MARYLAND(2020) Taillie, Dylan Maher; Elmore, Andrew J; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Golden-winged warbler, cerulean warbler, and wood thrush populations are in decline in the eastern United States. Golden-winged warblers rely on young forests – such as those created using silviculture – for nesting and early life stages; however, the loss of late-successional forest through timber harvest likely degrades habitat for cerulean warblers and wood thrush. To quantify these complexities, I mapped current habitat quality for these three species in Western Maryland using models based on forest metrics. The creation of young forest through silviculture and field succession scenarios was then simulated to project how modeled changes affect predicted habitat quality. Field succession scenarios and silviculture scenarios both improved predicted habitat quality for golden-winged warblers and wood thrush; however, for cerulean warblers, field succession scenarios improved habitat quality while silviculture scenarios degraded habitat quality. This modeling approach will assist managers in using funds to simultaneously improve habitat quality for multiple sensitive species.Item ELUCIDATING RECRUITMENT STRESSORS FOR THE MARYLAND STATE ENDANGERED COMMON TERN (Sterna hirundo) THROUGH USE OF A MINIMALLY INVASIVE SURVEILLANCE SYSTEM(2018) Marban, Paul Ramon; Murrow, Jennifer L; Prosser, Diann J; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In this thesis, I monitored two breeding colonies of the Maryland state endangered common tern (Sterna hirundo) using a surveillance system composed of video cameras and temperature loggers. This system was coupled with an in-depth image analysis of Landsat scenes to quantify island loss in the Chesapeake Bay and coastal bays of Maryland and Virginia from 1986 to 2016. Incubation duration was determined through analysis of both in-nest temperature and video footage. Incubation trends varied between colonies but an overall trend of nighttime desertion was observed on Skimmer Island as a result of predator presence. Island loss was documented in the region since 1986. Area of beach habitat, key for breeding populations of this species, increased in 1996 and 2011 as a result of sand accretion on coastal islands and the construction of Poplar Island. All other habitat types declined. This thesis is the first to document island loss in the Chesapeake Bay beyond 2011 and the first to quantify the impact of Poplar Island’s construction on the region. To promote future breeding of common terns in Maryland, resources must be allocated to create new habitat islands removed from the mainland and free of nesting predators. Existing islands must also be supplemented yearly with substrate to mitigate erosion from sea level rise.Item Mortality and Movement of Adult Atlantic Menhaden During 1966-1969 Estimated from Mark-Recapture Models(2017) Liljestrand, Emily Morgan; Wilberg, Michael J; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Atlantic Menhaden Brevoortia tyrannus is an economically and ecologically important forage fish. I built a multi-state mark-recapture model to estimate movement, fishing mortality, and natural mortality rates during 1966-1969. Movement from mid-Atlantic regions to North and South Carolina in the winter was lower than previously described, and natural mortality was approximately three times greater than previously estimated. Fishing mortality was highest in North and South Carolina. We evaluated the model’s performance by generating mark-recapture data sets from known values of mortality and movement then fitting the mark-recapture model to those data. The model estimated movement rates > 0.05 to within 33% of the true value even under different scenarios of spatiotemporally distributed releases and fishing effort. Distributing the fishing effort more evenly across regions substantially improved the estimates of movement and fishing mortality, and increasing the number of marked fish released had a small positive effect on accuracy of estimates.Item BIOLOGY AND MANAGEMENT OF REPRODUCTION IN CAPTIVE CRANES(2017) Brown, Megan Elizabeth; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)There are 15 species of cranes found throughout the world, 11 of which are listed as vulnerable or endangered. All 15 species are currently managed in captivity; however, with increased threats to wild crane habitats and populations, ex situ management becomes increasingly critical as a hedge against extinction. Reproduction and the production of offspring is required to ensure self-sustaining populations managed in ex situ conservation breeding programs. However, current reproductive success of the endangered whooping crane (Grus americana), as well as other species, maintained ex situ is suboptimal and hinders population sustainability and reintroduction goals. The objectives of this dissertation were to 1) develop a cryopreservation protocol for crane semen to improve genetic management in endangered cranes, 2) investigated seasonal hormone patterns and measured the impact of captive environment on hormone production and reproductive behaviors, and 3) retrospectively examine the effect of bird as well as management variables on egg fertility in whooping cranes. The findings demonstrated that 1) sperm of both whooping and white-naped crane performed better following cryopreservation when dimethyl-sulfoxide is utilized as a cryoprotectant, 2) seasonal fluctuations occur in hormone production in both sexes, while addition of a water feature to captive enclosures stimulated reproduction in females, and 3) female specific variables had the greatest influence on probability of egg fertility. Overall findings will help whooping crane management Continued research into the mechanisms controlling sperm sensitivity to cryo-damage, egg production, and fertilization are necessary to mitigate reproductive problems in captive crane species.Item Mark-Recapture Assessment of the Recreational Blue Crab (Callinectes sapidus) Harvest in Chesapeake Bay, Maryland(2016) Semmler, Robert Semmler; Reaka, Marjorie L; Hines, Anson H; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In Maryland, commercial blue crab (Callinectes sapidus) harvests are monitored through mandatory, annual harvest reporting, but no monitoring exists for recreational fishers. This study used a large-scale mark-recapture program to assess relative exploitation between the recreational and commercial fishing sectors in 15 harvest reporting areas of Maryland, then incorporated movement information and extrapolated reported commercial harvest data to generate statewide estimates of recreational harvest. Results indicate spatial variation in recreational fishing, with a majority of recreational harvests coming from tributaries of the Western Shore and the Wye and Miles Rivers on the Eastern Shore. Statewide, recreational harvest has remained 8% as large as commercial harvest despite management changes in 2008, and remains a larger proportion (12.8%) of male commercial harvest. In addition, this study provides detailed spatial information on recreational harvest and the first information on rates of exchange of male crabs among harvest reporting areas.