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The determination of the solar oxygen abundance is a topic that has long beenunder debate, where the exact value has varied between researchers. These variationsin the oxygen abundance have implications on our understanding of the Sun and itsinterior as well as our understanding of other stars. The aim of this report is to explorethe di erences between three observations; the Liège, Hamburg and SST, and their effecton the solar oxygen abundance calculated from the 777 nm triplet. In the reportit was found that the abundance from the Liège and SST data was lower and in betteragreement (A(O) ≈ 8.709 dex) compared to the Hamburg data (A(O) ≈ 8.732 dex).One of the potential reasons for these di erences explored in the thesis were the e ectsof magnetic  elds. After comparing the di erences it was argued that the SST dataset as well as the Liège could be considered more reliable compared to the Hamburg.The argued abundance was therefore of a somewhat lower value which does not helplessen the inconsistency between solar models and helioseismology. / Bestämningen av mängden syre i solen har länge varit ett debatterat område där det exakta numeriska värdet varierat bland forskare. Dessa variationer av mängden syre ger konsekvenser för vår förståelse av solen och dess inre samt för vår förståelse av andra stjärnor. Syftet med denna rapport är att utforska skillnaderna mellan tre observationer; från Liège, Hamburg och SST, samt deras påverkan på mängden syre i solen beräknad från 777 nm tripletten. Rapporten fann att mängden syre beräknad från Liège- och SST-datan både var lägre samt stämde bättre överens (A(O) ≈ 8.709 dex) i jämförelse med mängden från Hamburg observationen (A(O) ≈ 8.732 dex). En potentiell anledning till skillnaden i resultat som utforskades i denna uppsats var påverkan av magnetiska fält. Efter jämförelse av skillnaderna kunde det konstateras att datan från SST så väl som från Liège kan anses mer pålitliga i förhållande till Hamburg-datan. Den förespråkade mängden syre var åt det lägre hållet vilket inte bidrar till minskningen av avvikelserna mellan modeller av solen och mätningar via helioseismologi.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), brown marmorated stink bug, is an invasive, polyphagous pest that has disrupted integrated pest management programs in Mid-Atlantic tree fruit orchards since 2010. The amount of damage to fruit caused by H. halys feeding is highly variable, even within adjacent orchard blocks, and the influence of orchards and wild host plants nearby on H. halys relative abundance is unknown. Pheromone-based trapping studies conducted along woodland-to-orchard transects, along woodland borders at sites with and without adjacent orchards, and within the mid-canopy of several common wild host trees in woodland borders were used to investigate biotic factors underlying the variability of H. halys populations among sites within a geographically proximate area. Additionally, the retention duration of H. halys on wild and cultivated tree hosts was used as a proxy for host acceptability throughout the season. All trapping studies yielded significantly greater H. halys captures during the late season, and in the transect study, pyramid traps deployed at orchard and woodland edges during this period yielded the highest captures. The presence of orchards or open fields adjacent to woodlands had no significant impact on H. halys captures in sticky traps deployed along wooded edges, but captures varied significantly among orchard and open field sites. Among 11 common wild host plant genera surveyed at these sites, five genera, Elaeagnus, Fraxinus, Lonicera, Ailanthus, and Sassafras, were significantly related to H. halys relative densities. Conversely, studies measuring captures in small pyramid traps within the canopy of wild tree hosts revealed no significant differences among hosts at any point in the season, suggesting that this approach might not be appropriate for assessing host plant suitability. Finally, harmonic radar trials assessing host plant retention as a proxy for host suitability revealed that adults released on peach and pheromone-baited apple trees had significantly greater retention durations than those released on non-host, grass, and that adult retention duration increased from the early to late season. In combination, results indicate that the risk posed by H. halys to cultivated orchard crops varied across locations and seasonally, and may be related to the species composition of wild host trees in adjoining woodlands. / Doctor of Philosophy / Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive insect that has inflicted feeding damage on fruit grown in Mid-Atlantic orchards since 2010. The agricultural landscape in the Mid-Atlantic region complicates BMSB management, as many orchards are bordered by woodlots containing a variety of BMSB host plants. The amount of BMSB feeding injury at harvest can vary greatly among nearby orchards, and even within individual orchards, but it is unknown why these differences exist. Several BMSB trapping studies using pheromone-baited traps revealed that BMSB populations were greatest in the late-season, confirming previous work. Furthermore, captures in traps positioned in lines intersecting orchards and adjacent woodlots revealed late-season BMSB presence was greatest at the orchard and woodland edges. Captures in traps next to woodlots adjacent to orchards and open field sites indicated that the presence of orchards had no impact on captures, but that captures varied significantly among orchard sites and open field sites. A survey of the woody plants in the woodlots adjacent to these sites revealed that five host plant genera were strongly related to BMSB abundance. A study examining BMSB captures in small pyramid traps deployed in the canopy of several common wild tree hosts did not yield differences in captures among hosts at any point in the season, and thus was not a suitable method for assessing seasonal differences in BMSB host use. Finally, harmonic radar technology was used to assess how long BMSB remained on several wild and cultivated host plants at different points in the growing season, as a proxy for host suitability. Peach and pheromone-baited apple showed significantly greater adult retention durations than non-host, grass, and adults remained on host plants longer in the early than late season. Ultimately, these results should aid in the monitoring and management of BMSB by providing a broader understanding of factors underlying the presence and abundance of BMSB on a localized geographic scale.

Understanding the link between environmental factors such as disturbance events, land cover, and soil productivity to spatial variation in animal distributions and vital rates is fundamental to population ecology and wildlife management. The Longleaf pine (Pinus palustris; hereafter, LLP) ecosystem is an archetypal fire-mediated ecosystem, which has seen drastic reductions in land area due to fire suppression. Current restoration utilizes prescribed fire and hardwood removal, but more research is needed to understand the influence of these restoration efforts on the wildlife that exist in that ecosystem. As such, we conducted field surveys on Camp Blanding Joint Training Center and Wildlife Management Area to understand how fire influences relative abundances of mammalian predators, occupancy and species richness of avian species, guilds and communities, and vital rates of white-tailed deer (Odocoileus viginianus) fawns. Our results indicated that mammalian predator space use, and avian species richness were influenced by fire and land cover. Mammalian predator space use was altered by fire conditions and land cover. This mechanism may support predator management strategies that utilizes commonly management techniques for the restoration and conservation of the LLP ecosystem to indirectly alter predator distributions, which has the potential to positively affect the management of important species within this ecosystem. Some mammalian mesocarnivores historically common throughout the southeastern United States were rarely detected, suggesting more research is needed to identify the cause of the potential decline in mesocarnivores in the Southeastern United States. Avian species richness at the community level was positively influenced by the heterogeneity of post fire conditions, or pyrodiversity. Avian species richness of the cavity nesting guild was negatively influenced by increasing time-since-fire. Our results suggest that managers can promote avian community diversity by reducing the size of burn units to create areas with multiple adjacent burn units, with unique fire histories and a mosaic of post-fire conditions. Lastly, fawn recruitment was greater on the higher productivity site than the low productivity site on CB. However, within sites soil productivity did not have a demonstrable effect. In fact, we observed differences between sites, but did not observe any effects of covariates on spatial variation in density or survival of fawns within sites. Although we did not explicitly test the factors influencing our parameters between sites, we hypothesize that the variation in coyote activity rates as well as soil productivity and its subsequent effects (i.e. forage availability, concealment cover, and land cover type) likely drove the differences we saw between sites. These results are relevant to local managers and provide support for unit-specific, deer management on CB. In conclusion, understanding the influence of fire in a frequently burned landscape allows us to better inform management of predators and avian communities using prescribed burns, and the differences in deer populations between areas allowed us to better in inform managers on harvest quotas so that the magnitude of the effect of harvest can better match the population vital rates of each area. / Master of Science / Understanding the link between environmental factors such as fire, land cover and soil productivity is essential for wildlife managers to maintain healthy wildlife populations. The Longleaf pine (Pinus palustris) ecosystem requires frequent fire and has seen drastic reductions in land area due to fire suppression. Current restoration utilizes prescribed fire, controlled burning of an area, and hardwood removal, logging hardwood trees such as oaks, but more research is needed to understand how this restoration influences the wildlife in the longleaf pine ecosystem. As such, we collected data collected from Camp Blanding Joint Training Center and Wildlife Management Area to understand how fire influences the relative numbers of mammalian predators, the distribution and species richness (i.e. number of unique species) of avian species, guilds and communities, and vital rates (i.e. births, survival to a certain age) of white-tailed deer fawns. Our results indicated that mammalian predator distributions, and avian species richness were influenced by fire and land cover. Mammalian predator space use was altered by fire conditions and landcover, which supports a predator management strategy that utilizes prescribed burning and hardwood removal used in restoration and conservation of the LLP ecosystem to indirectly alter predator distributions. Some mammalian mesocarnivores (i.e. foxes, skunks, weasels, etc.) historically common throughout the southeastern United States were rarely detected, suggesting more research is needed to identify the cause of the potential decline of cryptic mesocarnivores in the Southeastern United States. Avian species richness, number of unique species, at the community level was positively influenced by pyrodiversity, the number of unique burn years in an area. This supports and further extends the 'pyrodiversity begets biodiversity' hypothesis for avian species, which states that greater pyrodiversity increases the diversity of bird species in that area. Avian species richness of cavity nesting birds decreased with increasing time since fire. Our results suggest that managers can promote avian community diversity by reducing the size of burn units to create areas with multiple adjacent burn units, with unique fire histories and a mosaic of post-fire conditions. Lastly, fawn recruitment was greater on the higher productivity site than the low productivity site, however, within sites soil productivity did not seem to influence birth and recruitment. Although we did not statistically test the factors influencing our parameters between sites, we hypothesize that the variation in coyote activity rates as well as soil productivity and its subsequent effects (i.e. forage availability, concealment cover, and land cover type) likely drove the differences we saw between sites. These results are relevant to local managers and provide support for managing deer differently across both sites. In conclusion, understanding the influence of fire in a frequently burned landscape allows us to better inform management of predators and avian communities using prescribed burns, and the differences in deer populations between areas allowed us to better in inform managers on harvest quotas so that the magnitude of the effect of harvest can better match the population vital rates of each area.

Field studies were conducted in southwestern Virginia to determine the bionomics and ovipositional preferences of Culex restuans Theobald and Culex pipiens Linnaeus using ovitraps and gravid traps. Both species have been implicated as enzootic and epizootic vectors of West Nile virus (WNV) and these studies provide information on the relative abundance of gravid mosquitoes. Ovitraps were used in the summers of 2002 and 2003 to measure the oviposition activity of Culex mosquitoes, mainly Cx. restuans and Cx. pipiens. In 2002, 1,345 egg rafts were collected from 5 traps set at different locations in the New River Valley (NRV). Cx. restuans constituted 93.2% of the catch; the remainder was Cx. pipiens (6.7%) and Cx. salinarius (<1%). In 2003, 4 ovitraps were placed at each of 6 locations in the NRV. Of 9,794 egg rafts collected, Cx. restuans comprised 92.8%, Cx. pipiens 6.5%, and Cx. salinarius <1%. Oviposition patterns were similar in both years. Cx. restuans oviposition was detected about mid-May, and raft numbers were highest in late June and the middle of July and then showed a steady decline throughout the remainder of each season. Cx. pipiens oviposition activity began later in the season and gradually increased, reaching its peak in August. Although the number of egg rafts of Cx. restuans decreased in August and September while the number of Cx. pipiens egg rafts increased, a crossover in the relative abundance of the two species never occurred. In 2003, the attractiveness of four infusions (cow manure, straw, grass, and rabbit chow) were compared in oviposition traps. For Cx. restuans, the manure infusions collected more egg rafts than the other three infusions for the first four weeks, with two of the weeks showing significance. During week 1, the manure infusions collected significantly more egg rafts than straw (P<0.01), grass (P<0.01), and rabbit (P<0.001). During week 2, manure collected more than grass (P<0.05) and rabbit (P<0.01). The straw and grass infusions yielded the most egg rafts after week 2, and only three weeks showed any significance. When traps began to collect Cx. pipiens, the majority were collected in the straw and grass infusions. During week 6, the hay infusions had significantly more egg rafts when compared to manure (P<0.001) and rabbit infusions (P<0.001) and the grass infusions had significantly more when compared to manure (P<0.05) and rabbit (P<0.01). Week 9 also showed significance when the hay infusions collected significantly more egg rafts than manure and rabbit (P<0.01 and P<0.01, respectively). The attractiveness of the cow manure and straw infusions were also compared in gravid traps. Because it is difficult to accurately discriminate between Cx. pipiens and Cx. restuans that have been collected as adults in gravid traps, these collections were combined into Culex. More Culex mosquitoes were collected in the manure infusions for the first two weeks (P<0.05). No significant differences were found between the numbers of mosquitoes captured in the traps baited with the different infusions after the second week. The shift observed in oviposition preference for both types of traps may have been due to cooler temperatures in the early part of the season. The straw infusions were aged outdoors for 3 days prior to use, and a sufficient incubation temperature to generate the bacteria producing the attractant chemicals may not have been attained. In addition, the manure lagoon had been drawn down and the consistency of the remaining manure became much drier by this time. No chemicals were ever added to the lagoon, but the draw down may have affected the attractiveness of the manure. / Master of Science

Post-pelagic juvenile and subadult Kemp's ridley sea turtles (Lepidochelys kempii) (20-40 cm straight carapace length) utilize nearshore waters of the northwestern Gulf of Mexico as nursery or developmental feeding grounds. This study utilizes 10 years of entanglement netting data to characterize long-term abundance and distribution of Kemp's ridley sea turtles at index habitats in this region. Netting surveys were conducted during April-October 1993-2002, primarily at Sabine Pass, Texas and Calcasieu Pass, Louisiana. Additionally, this study takes an ecosystem-based approach to understanding factors influencing Kemp's ridley in-water abundance and distribution via the development of a conceptual model incorporating data on nesting dynamics, environmental conditions, prey availability, and predation pressure. Overall monthly mean ridley catch-per-unit-effort (CPUE) peaked in the beginning of summer (April-June), probably in response to rising water temperatures and seasonal occurrence of blue crab prey. Annual mean ridley CPUE across all study areas peaked in 1994, 1997, 1999 and 2002, suggesting a 2-3 year cycle in abundance that may be related to patterns in clutch size or hatch success at the Rancho Nuevo, Mexico nesting beach. However, ridley CPUE in nearshore waters remained relatively constant or decreased slightly even as number of hatchlings released from Rancho Nuevo increased exponentially. Annual declines in Texas strandings since 1994 and subsequent increases in Florida counterparts since 1995 suggest a shift in ridley distribution from the western to eastern Gulf in recent years. Significant declines in ridley CPUE at Sabine Pass since 1997 coincided with a concurrent reduction in blue crab size, but a similar trend was not detected at Calcasieu Pass. Kemp's ridley occurrence at study sites was not significantly related to shrimping activity/by-catch. There also were no biologically significant relationships between Kemp's ridley CPUE and abiotic factors, nor were ridleys deterred from utilizing areas frequented by bull sharks. Overall, nesting dynamics and prey availability were conceptual model components appearing to have the greatest influence on nearshore ridley occurrence.