Par Pond is a man-made 1120 ha cooling reservoir located on the Savannah River Site near Aiken, South Carolina. From 1972-1978 a detailed study on the status of the alligator in Par Pond was conducted by Tom Murphy (unpub. MS thesis Univ. of GA, 1977). Murphy estimated that approximately 110 alligators inhabited Par Pond with an adult (> 1.8 m) to juvenile (< 1.8 m) ratio of (1.8:1), an overall sex ratio of 3.2:1, and an average of only 2.3 nests/yr. The purpose of this study (1986-1989) was to determine the current population size and structure, determine how the population has changed in the last 15 years and to examine growth and survival of juvenile alligators. Data were collected by monthly night-time eyeshine counts aerial surveys, capturing animals, and locating and following the fate of nests. There was a strong positive correlation between water temperature and the number of alligators observed during eyeshine counts. Both eyeshine counts and aerial surveys were highest in spring and varied seasonally. A total of 184 different non-hatchling and 157 hatchling alligators were captured between May 1986 and November 1988. Population estimates and size distributions based on capture data indicate that over the last 15 years the population has increased from approximately 110 to 200 alligators, and the size distribution has shifted from one dominated by large adults to one that has a higher proportion of juveniles. The current sex ratio (2.6:1) is not significantly different from that reported by Murphy (1977, 3.2:1). However, the average number of nests/yr has increased from 2.3 to 4.0. Data on juvenile growth and survival show that the growth rate of hatchlings (32.9 cm/yr total length) is greater than that of animals age 1-3 (21.6 cm/yr total length) and survival of all ages is variable between years and between clutches. Results from this study indicate that from 1972-988 the population has increased ac an average exponential rate of 6 % per year. If conditions in Par Pond do not change, the population size should continue to increase.

Wildlife management and conservation frequently rely on understanding mechanisms that influence distribution and abundance of animals. I quantified space use for a population of inland riverine adult male alligators in Mississippi. Results indicated habitat selection is a scale-dependent process and aquatic vegetation, water depth, and water temperature may be important factors influencing alligator foraging and thermoregulation. Apparent habitat suitability and low alligator density did not manifest in an observed body size-based dominance hierarchy. I also analyzed long-term Mississippi alligator spotlight survey data for trends and effects of environmental covariates on counts. Model results indicated alligator counts have increased over time. This response likely reflects benefits accrued from decades of protection and wetland conservation. Distance sampling does not appear to be a feasible monitoring technique for riverine alligator populations. Nevertheless, it is important that survey protocols and monitoring programs account for imperfect detection and model important covariates.

The alligator gar Atractosteus spatula is a euryhaline fish found in the Gulf of Mexico and surrounding drainages. However, the extent of its hypo-osmotic abilities are not well understood. To determine effect of salinity on growth, metabolic rate, and osmoregulation abilities the following question was developed: when does the alligator gar have the osmoregulatory capabilities to survive in hyperosmotic environments? To answer this question, two different age groups (60 and 330 days after hatch [DAH]) of juvenile alligator gar were exposed to 4 different salinities (0, 8, 16, and 24 ppt) for a 30-day period. Specific growth rate, oxygen consumption rate, plasma osmolality, plasma ion concentrations, tissue Na+, K+-ATPase activities, and drinking rate were measured. I determined that the 60 DAH alligator gar had a greater ability to grow and regulate ions than did the 330 DAH alligator gar in increased salinity.

Histological analysis of long bone thin sections is commonly used to infer growth rates and ecology of extinct vertebrates, particularly within Archosauria. However, most comparative neontological studies have used small samples of captive individuals, limiting the scope of variation. To fill this gap, 44 femoral thin sections of wild Alligator mississippiensis were prepared and analyzed. Comparison of slides revealed that larger individuals from cooler climates tend to show more LAGs compared to southerly A. mississippiensis of similar size, however, there is considerable variation. This pronounced variation in wild specimens emphasizes the need to use caution when interpreting paleohistological data with little modern comparative samples. Finally, thin sections of early Pliocene Alligator sp. fossils from the Gray Fossil Site (GFS), Washington Co., Tennessee were prepared. The GFS Alligator grew more slowly than A. mississippiensis examined and may have reached reproductive maturity at smaller sizes.

There is a vast diversity in tetrapod lung branching morphology. Phylogenetically, much of the pulmonary diversity among vertebrates appears to arise from the way epithelial tubes branch or form saccular (cyst) structures. Fgf10 activity has been shown to play a critical role in regulating branch versus cyst morphology. We hypothesize that the species-specific differences in lung morphology may be primarily due to species-specific differences in Fgf10 expression. To test this hypothesis, we have performed bioinformatic analyses on the Fgf10 locus and have identified a conserved 11 kb noncoding region that potentially contains the Fgf10 lung enhancer. We are taking a large DNA sequence upstream of the Fgf10 gene of the American Alligator and swapping it into the orthologous locus in the genome of chicken primordial germ cells (cPGCs). We are accomplishing these swaps by using a combination of homology directed repair (HDR) and recombinase mediated cassette exchange (RMCE) in cPGCs. These edited cell lines can be used to generate germline chimeric chickens capable of producing offspring that putatively drive Fgf10 expression in the lung under control of regulatory sequences from various other reptiles. We have also generated a cPGC line where, through RMCE, we can easily target any enhancer from any organism to drive a GFP reporter as a means to test the temporal and spatial regulatory characteristics of these enhancers. This work is funded through a BYU Turkey Vaccine Grant and a Skaggs Mentoring Grant.

Crocodilians and birds comprise sister taxa of archosaurs, the development of these vertebrates occurs within an egg case that leaves developing embryos susceptible to fluctuations in the nesting environment. Studies suggest that sub-optimal conditions alter morphological growth and cardiovascular physiology. Regulation of the cardiovascular system is immature in the subjects studied, and embryos may rely on humoral rather than neural control of the cardiovascular system. The primary focus of this dissertation was to assess regulatory mechanisms responsible for maintenance of arterial pressure and heart rate. Dehydration stress had marked effects on embryo growth, and altered baseline cardiovascular parameters, while leaving the response to humoral regulator, angiotensin II (Ang II), unaffected. However, dehydrated alligator embryos developed cholinergic tone on heart rate. Hypoxic incubated chicken embryos were reduced in embryo mass, and altered response to humoral regulatory components Ang I and adenosine in addition identifying a novel regulatory component of the cardiovascular response to acute hypoxia. Collectively, these studies add to the existing knowledge of cardiovascular physiology in embryonic archosaurs and suggest that some components of cardiovascular regulation are plastic following developmental stress.

As the nineteenth century drew to a close, people living in coastal Louisiana noticed that local rodents called muskrats were rapidly increasing and quickly becoming pests by digging up crops and into levees. Property owners soon demanded their elimination, but to the ire of many, Louisiana officials chose to develop a market for muskrat fur and protect its supply through management laws. The state sought the cooperation of trappers in order to maintain global demand, but when nutria were released alongside the muskrat, the ecological balance of the marsh was permanently altered. Muskrats shrank back into obscurity, and trappers struggled to embrace the nutria as a substitute. This thesis will trace the Louisiana muskrat industry's development starting with its rise in the 1890s, continuing through its years as a leading furbearer, and ending with its replacement by the nutria in the 1960s.

Orientador: Mary Rosa Rodrigues de Marchi / Co-orientador: Adriana Paiva de Oliveira / Banca: Maria Lúcia Ribeiro / Banca: Carolina Lourencetti / Banca: Mario Sergio Galhiane / Banca: Maria Eliana Lopes Ribeiro de Queiroz / Resumo: Mostramos aqui a ocorrência de poluentes orgânicos persistentes em ovos de jacaré-do-Pantanal (Caiman yacare), coletados em dois municípios do estado de Mato Grosso (Brasil), em 2012 e 2013. p,p'-DDE foi o composto encontrado em maior concentração (51,3 - 78,1 ng g-1 de ovo liofilizado) em ambas as regiões estudadas. Para a extração de pesticidas organoclorados - OCPs - (p,p'-DDD, p,p'-DDE, o,p'-DDT, o,p'-DDD, o,p'-DDE, β-endosulfan e endosulfan sulfato) e bifenilas policloradas - PCBs - (congêneres 28, 52, 101, 118, 138, 153 e 180), o conteúdo total de ovos de C. yacare, exceto a casca, foi homogeneizado, liofilizado e submetido a um método de extração sólido-líquido com partição em baixa temperatura (ESL-PBT) que previamente foi otimizado e validado. Foi utilizado um cromatógrafo a gás (CG) com detector por captura de elétrons (ECD) para a detecção destes analitos. PCB 209 a 10 ng mL-1 e tetrabromobenzeno (TBB) a 10 ng mL-1 foram utilizados como padrão interno e como padrão de recuperação (surrogate), respectivamente. O método de extração foi otimizado através de um estudo quimiométrico que incluiu um planejamento fatorial 24 com triplicata do ponto central, para determinação das melhores condições de análise dos compostos de interesse. Volume de solvente extrator (8 - 12 mL), tempo de agitação em vortex (1 - 5 min), tempo de centrifugação a 2.500 rpm (5 - 15 min) e tempo de congelamento (4 - 12 h) foram as variáveis consideradas e testadas em dois níveis, mais a triplicata do ponto central. A recuperação normalizada foi utilizada como resposta para avaliação dos fatores que influenciam o método de extração. As respostas normalizadas foram submetidas ao teste t de Student para determinação dos fatores significativos e as interações entre os fatores foram avaliadas a partir da superfície de resposta. O método otimizado inclui 12... / Abstract: This work shows the occurrence of persistent organic pollutants in the eggs of Caiman yacare, collected in two regions from Pantanal mato-grossense (Brazil), in 2012 and 2013. p,p'-DDE was the analyte found in higher concentration (51.3 - 78.1 ng g-1 of lyophilized egg) in both regions studied. For the extraction of organochlorine pesticides (p,p'-DDD, p,p'-DDE, o,p'-DDT, o,p'-DDD, o,p'-DDE, β-endosulphan and endosulphan sulfate) and polychlorinated biphenyls - PCBs - (congeners 28, 52, 101, 118, 138, 153, 180) C. yacare eggs, except shell, were homogenized, lyophilized and was applied a method solid-liquid extraction with low temperature partition (SLE-LTP) optimized and validated. A gas chromatograph (GC) with electron capture detector (ECD) was used. PCB 209 10 ng mL-1 was used as internal standard and tetrabromobenzene (TBB) 10 ng mL-1 was used as surrogate. The optimization was based on a chemometric study included a 24 factorial design with three replications of the central point to determine the best conditions for the analysis of compounds of interest. Volume extracting solvent (8-12 mL), vortexing time (1-5 min), centrifugation time at 2,500 rpm (5-15 min) and time freezing (4-12 h) were the variables considered and tested at two levels, plus the triplicate central point. The normalized recovery was used as a response to evaluation of factors that influence the extraction method. The normalized responses were submitted to the Student's t-test to determine the significant factors and interactions between factors were evaluated from the response surface. The optimized method includes: extractor solvent 12 mL (acetonitrile: ethyl acetate - 6,5:1,5 v/v), 5 min of vortexing time, 15 min centrifugation at 2,500 rpm and 12 hour freezing. To validate the method, The chromatographic area of each analyte relative to the internal standard chromatographic area vs. concentration were used to... / Doutor

Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominated sedimentary rocks. The association of gold and related arsenic with faults at the margins of a Jurassic pluton and sedimentary rocks suggests that ore fluids migrated along faults and fracture s. Permeability of the faults changed over time within the Casino deposit, where the ore-controlling fault was a distributed conduit in the early stages of mineralization but a barrier and a localized conduit a t opposite ends of the deposit during later stages. Results indicate that faults may significantly influence patterns of ore deposition and change character over deposit-scale distances, and continued slip along faults may create clay-rich low-permeability faults that are mineralized during early stages of development.

The American alligator (Alligator mississippiensis) has been frequently studied in large reservoirs and coastal marshes. Large ontogenetic shifts in their diet and morphology have been linked with changes in habitat use, with adult males using deep, open water and juveniles and nesting females relying on vegetated marsh. In certain regions of the inland portion of the alligator’s range, these different aquatic habitats are represented by seasonal wetlands and riverine systems that are separated by a terrestrial matrix. Ontogenetic habitat shifts, therefore, would require overland movements between systems, which has important implications for conservation of the species. I tested several commonly used methods of surveying alligator populations to determine the most effective method of studying alligators in seasonal wetlands. I then used systematic trapping, nest surveys and radio telemetry to determine habitat use and overland movement rates by different sex and size classes. I found that seasonal wetlands provided nesting and nursery sites for these inland alligator populations, but that both juveniles undergoing an ontogenetic shift and nesting females move between the wetlands and riverine systems. Overland movements by alligators between the wetland and riverine habitats establish a level of functional connectivity between these aquatic ecosystems. I constructed a habitat suitability index of both the wetlands and the surrounding landscape to determine which patch and landscape characteristics were important to wetland use by alligators. I found that both descriptive wetland characteristics and the spatial relationships between wetlands were important predictors of alligator use. Overland movement was related to upland landuse as well as distance between aquatic habitats. Conserving a variety of wetland sizes and types within an intact upland matrix is critical to maintaining connectivity across the landscape. Furthermore, understanding how species may act as mobile links between ecosystems, particularly those with ontogenetic niche shifts, illustrates the importance of approaching conservation from a landscape perspective.