Since their recent introductions into Florida waters, three nonnative species [Perna viridis Linnaeus, 1758 (Asian green mussel), Mytella charruana d'Orbigny, 1846 (charru mussel) and Megabalanus coccopoma Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster (Crassostrea virginica Gmelin, 1791), which is a keystone species that provides important ecological services and economic benefits. To test the potential effects of P. viridis, M. charruana and M. coccopoma on C. virginica, I addressed the following questions: 1a) Does the presence of nonnative species decrease oyster larval settlement? 1b) Do oyster larvae avoid settling on oyster shells to which nonnative species are attached? 2a) Do nonnative species decrease survival of juvenile oysters (spat)? and 2b) Do nonnative species hinder spat growth? My manipulative experiments showed that the tested nonnative species influenced settlement, growth and survival of C. virginica in unique ways. Megabalanus coccopoma decreased the total number of settled oyster larvae, but did not influence larval preference or survival and growth of spat. Perna viridis negatively influenced larval settlement and oyster larvae avoided settling on shells of P. viridis. Mytella charruana had no influence on the total number of settled larvae but oyster larvae avoided settling on oyster shell with M. charruana or on the mussel shells themselves. Furthermore, both nonnative mussels negatively affected the survival of juvenile oysters, but only M. charruana reduced spat growth. These three nonnative species should be classified as invasive species because all had negative effects on the native oyster C. virginica.

Populations of Crassostrea virginica within Mosquito Lagoon, Florida have recently undergone significant die-offs, which are a subject of major concern. Restoration efforts within Mosquito Lagoon are focusing on reconstructing the three-dimensional reef habitats. Before effective protocols can be established, however, important questions about the sources of juvenile and adult oyster mortality must be answered. Potential causes of Crassostrea virginica mortality in the Indian River Lagoon system include sediment loads, competition, predation, and disease. My research focused on the interactions between oysters and the competitors that may affect the settlement, growth, and survival of Crassostrea virginica. The four objectives of my thesis research were to: 1) identify potential oyster competitors in Mosquito Lagoon, 2) determine if the sessile species recruiting to oyster shells have changed over time, 3) determine how the dominant competitors, barnacles, affect oyster settlement, growth and survival, and 4) determine if oyster or barnacle larvae are better able to settle in increased sediment and flow conditions that are associated with high levels of recreational boating. Lift nets were deployed within Mosquito Lagoon to determine available competing species. I collected species inventory data at six sites to determine the sessile invertebrate species (competitors) present on oyster reefs. Nets were deployed intertidally, just above mean low water, on living oyster reefs. One and a half liters of live and dead oysters were placed within the nets upon deployment. The nets were picked up monthly and surveyed for all fauna. Upon retrieval, all oysters within each net were brought back to the lab where all sessile organisms were immediately identified and returned to the lagoon. This survey began June 2004 and continued for one year. Shells from historic shell middens (up to 15,000 years old) were examined to determine if the sessile species settling on oyster reefs have changed over time. Similar species were found on both shells of historic and extant reefs. One notable exception was the appearance of Balanus amphitrite, an invasive barnacle, on the extant reefs. Balanus amphitrite is thought to have invaded Mosquito Lagoon approximately 100 years ago. This has resulted in a five fold increase in barnacle abundance per oyster shell. Balanus spp. were identified as important potential competitors and thus my research focused on spatial competition between C. virginica and native versus invasive barnacles of the area. Over 300 barnacles, including a native species, Balanus eburneus, and an invasive, Balanus amphitrite, have been counted on a single oyster shell. To determine how Balanus spp. affected settlement, growth, and survivorship of C. virginica, laboratory and field experiments were conducted in which densities of Balanus amphitrite and Balanus eburneus were manipulated. Density treatments included: no barnacles (control), low, medium, and high coverage of barnacles. Laboratory settlement trials with cultured oyster larvae were run in still water and flow (recirculating flume) using all barnacle density treatments. Additionally, all treatments with 7-day oyster spat were deployed in the field to follow oyster spat growth and survivorship. Settlement was counted by microscopy, and growth and survivorship were measured every 3 days for 4 weeks. Settlement of oysters was affected by barnacle presence only in flowing water. Still water trials showed no oyster preference related to any barnacle density or species. The presence of barnacles affected the growth and survivorship of oyster spat. However, there were no species specific differences. Studies suggest that recreational boating activities, especially boat wakes that cause sediment resuspension, may decrease recruitment and this may then provide an advantage to sessile competitors less affected by flow and sediment loads. To address these issues, replicated laboratory trials were run in a laboratory flume to quantify the effects of water motion (0, 5, 10 cm/s) and sediment loads (0, 8, 16 g/ml) on oyster recruitment and the recruitment of an important, relatively new competitor in the system, the barnacle Balanus amphitrite. If B. amphitrite settles in a wider variety of flow rates and sediment conditions, it may have a competitive advantage over the native oyster in this space-limited habitat. I found that high flow and sediment loads reduced larval settlement of C. virginica. Alternatively, settlement of cyprids of B. amphitrite did not differ among treatments. Thus, continuous boat traffic during settlement times should favor recruitment of the invasive barnacle Balanus amphitrite over the native oyster Crassostrea virginica. Determination of the competitive interactions of Crassostrea virginica in Mosquito Lagoon gives us important insights into the ecological conditions necessary for reestablishment of these oyster populations. Crassostrea virginica in Mosquito Lagoon was significantly impacted by barnacles; settlement, growth, and survivorship were all reduced by Balanus spp. This information will help resource managers in planning restoration techniques to minimize oyster and barnacle competitive interactions and increase Crassostrea virgininca success.

Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and macroinvertebrate predators. I determined the relationship between the presence of Cuban Treefrogs and twelve limnological (% vegetation, slope, pond age, pH, % dissolved oxygen, air temperature, water temperature, turbidity, conductivity, depth, perimeter, and area) and seven landscape characteristics (% canopy closure over ponds, building density, distance to nearest building, road density, distance to nearest road, distance to nearest forest stand, and % forest cover), plus five biotic factors (native amphibian richness and abundance, fish richness and abundance, and macroinvertebrate abundance). No relationship existed between native amphibian abundance or species richness and the presence or absence of Cuban Treefrogs. Ponds with a greater percentage of vegetation, large perimeters, and low pH and turbidity had greater native amphibian species richness. Cuban Treefrogs were more likely to be found in ponds with a greater percentage of aquatic vegetation and small perimeters. My results show that building large retention ponds containing low-turbidity water will restrict colonization by Cuban Treefrogs and maintain species richness of native amphibians.

Mangrove ecosystems are among the world's most endangered biomes; nearly one-half of the overall coverage is threatened by human activity, invasive species, and global climate change. Mangroves play an important ecosystem role through detrital production and by providing: fisheries and wildlife nursery habitat, shoreline protection, a sink for nutrients, carbon, and sediment. In addition to human activity, the Florida mangroves (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle) are being threatened by the invasive Brazilian pepper (Schinus terebinthifolius). This study was performed along a 261 km stretch of the east coast of Florida from Sebastian Inlet to the northern extent of mangroves, near St. Augustine. It entailed two parts. The first examined the phenology and leafing rates of the four species and attempted to find if there was a relationship between growth and latitude or temperature. Although a correlation between peaks in temperature and phenology was observed for all species, no leafing pattern could be discerned. In terms of mangrove growth for branch diameter, a logarithmic model (y=a + b·log [Initial diameter]) best fitted the data for R. mangle and L. racemosa but neither latitude nor temperature appeared to be important. However, S. terebinthifolius' and A. germinans's branch diameter growth were best represented by a logarithmic model (y=a + b·log [Initial diameter] + c·log x2) that incorporated temperature and latitudinal respectively. In the second part, a simulation model was developed to focus on understanding the relationships between establishment and competition among the three mangrove species and the invading S. terebinthifolius. This model was run under various invasion and/or climate change scenarios to determine possible outcomes under global climate change with or without the presence of S. terebinthifolius. Conclusions were drawn that under all scenarios of invasion, other than sea level rise as part of global climate change, S. terebinthifolius would dominate the landscape if allowed to invade and establish in areas in which it is not currently present although the amount of this response is dependent on the S. terebinthifolius response curves.

Diabetes mellitus is a potentially lethal disease that affects 7.6 percent of American people. In the US, it is recognized as the 6th leading cause of death. Failure to control blood glucose levels (BGL) in patients with either type of diabetes can lead to other serious complications as well, such as loss of limb, blindness and other health problems. Controlling and monitoring the BGL in post-op and intensive care patients in the hospital is also vital to their health. Currently the most reliable method of monitoring BGL is through an invasive procedure which monitors the amount of glucose in blood directly. A non-invasive glucose sensor would drastically improve the treatment of sensitive patients, and serve to improve the quality of diabetic patients' lives. This glucose sensor is strongly based upon the mercury sensor developed by F.E. Hernandez and his colleagues. Glucose is used as a reducing agent to reduce mercury from Hg2+ to Hg0, which will form amalgams with the gold nanorods in solution. The change in aspect ratio of gold nanorods leads to a change in the UV-Visible spectrum of the solution. The blue shift seen was measured and correlated with the glucose concentration of the system. The system was then tested varying conditions such as pH, temperature, gold nanorod concentration, and mercury concentration. A preliminary study of the kinetics of the reaction was also done. The results showed a limit of detection of 1.58x10-13 and a linear dynamic range covering the concentrations of human tear glucose levels that are currently cited in the literature.

This study contributes to the discussion of managing tourism to a protected area in a developing country (Galapagos, Ecuador). The first part of the analysis provides quantitative data about preferences of tourists and potential impacts on park revenues from price discrimination. It uses the data from a choice experiment survey conducted in the summer of 2009 in which these four attributes of a tour of the Galapagos were described: tour length, depth of naturalist experience, level of protection of Galapagos from invasive species, and price of the tour. On average the Galapagos tourist would be willing to pay slightly more than 2.5 times for a trip with a high-level of environmental protection than for a trip that is equivalent on all other characteristics but has a lower level of environmental protection. The mean marginal willingness to pay (MWTP) for a trip with an in-depth naturalist experience is 1.8 times more than that for a trip with a less detailed naturalist experience but equivalent on other characteristics. The relatively inelastic demand for travel to the islands would allow managers to adjust access fees to shift the distribution of length of trips while not affecting the revenues. The second part of the analysis evaluates the influence on travel to the islands by depicting Galapagos as a standard market commodity as well as depicting it as an environmental commodity. This analysis compares the results obtained from two different choice experiment surveys given to tourists finishing their trip to Galapagos. One survey design portrays the archipelago as a standard holiday island destination while the other design highlights the uniqueness and vulnerability of the islands’ biodiversity and the challenges that tourism poses to the islands’ conservation. Results suggest that additional information modified an individual's decision-making process. In the first design case (which excludes environmental information), the influence of attributes such as length and depth of natural experience is attenuated. The MWTPs estimated for these attributes are smaller in absolute terms although differences on the MWTP are not statistically significant.

Microstegium vimineum, or Japanese stilt grass, is an invasive species that readily outcompetes native vegetation and is of poor forage quality for wildlife. This species is widespread throughout the southeastern United States, including North Carolina. Much of this region is privately owned and there is a gap in the literature providing succinct information about the best methods of treatment, timing of treatment, and effects of treatment on native herbaceous plants in this region. In two parts, this study seeks to address this gap by employing treatments that are easily accessible to landowners at different times during the growing season and assessing the effects on the herbaceous plant community post-treatment. Results of this study found that application of glyphosate was the most effective treatment at M. vimineum removal, application of household vinegar was the most effective at increasing post-treatment species richness and diversity, and that seasonality did not play a role in the effectiveness of treatment options. This study will increase landowner knowledge on treating this invasive successfully and choosing a treatment that fosters an understory that meets their management goals.

Temperature represents a major driving force in biology as it influences essential functions across multiple levels of biological organization. The role of temperature is especially important for ectothermic animals, whose biotic processes are dependent on both body and environmental temperature. Assessing the relationship between temperature and organismal performance represents an important research direction as temperatures continue to warm under anthropogenic climate change. Chapters two and three are focused on a recently colonized population of the invasive Mediterranean House Geckos at the northern edge of their invasion front. These chapters examine the ecological and physiological factors that enable these lizards to persist in a cooler and more temperate environment than their native range. The thermal breadth of a reptile greatly influences its ability to tolerate a thermally variable environment, particularly when environmental options are limited for behavioral thermoregulation. These chapters explore the thermal performance of this species, and the results show that the eurythermality of these geckos promotes their rapid colonization of novel environments despite experiencing prolonged periods of cool temperatures. Chapters four, five, and six, by contrast, shift focus to larval amphibians to explore the constraints and factors underlying plasticity in acclimation to temperature extremes. As habitats continue to warm with climate change, ectotherms with limited capacity to thermoregulate, such as larval amphibians in shallow ponds, will be under a heightened threat of heat stress and mortality. Resultantly, identifying different factors that can increase organismal heat tolerance would reduce the risk of overheating and promote survival. Chapters four, five, and six explore this topic by measuring the critical thermal maximum (CTmax) of larval wood frogs. Chapter four focuses on the tradeoff between basal CTmax and plasticity of CTmax and its consequences for how a larval anuran responds to an acute heat shock. Chapter five examines the role a viral pathogen, ranavirus, has on larval CTmax. Surprisingly, a lethal dose of ranavirus did not reduce CTmax which goes against the common pattern of pathogenic infections lowering host heat tolerance. Lastly, chapter six explores the relationship between the gut microbiota and host CTmax with a particular focus on cross-species microbiota transplants. In line with our prediction, transplanting the gut microbiota of a heat-tolerant donor species promoted greater CTmax in the heat-sensitive recipient species.

To alleviate the poor ergonomics which surgeons suffer during knee arthroscopy, a semi-robotic device with braking mechanism is created for intraoperative assistance. A slitted ball joint assembly is developed to transmit the clamping force to the arthroscope inside. Ball deformation and stress at various angles to the vertical and clamping forces is recorded through Abaqus Finite Element Analysis (FEA). Contact forces between the scope and inner surfaces of the ball is also computed in FEA at different clamping forces. The von Mises stress occurring in the ball joint is under the yield stress limit for polyethylene, and there is noticeable force preventing the scope from sliding along the ball through-hole under clamping. A prototype of this device is constructed for proof-of-concept.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24243号 / 農博第2522号 / 新制||農||1094(附属図書館) / 学位論文||R4||N5414(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 松浦 健二, 教授 大門 高明, 教授 日本 典秀 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM