Terracing is a novel technique used to combat coastal marsh loss in Louisiana and Texas. Terraces are assumed to slow marsh erosion, decrease pond depth, and encourage vegetation expansion. Terraced ponds have never been evaluated as habitat for waterbirds, which heavily depend on Louisiana�s coastal marshes. From April 2005 to April 2006, I monitored waterbird species richness and density through time to estimate effects that terracing has on habitat quality. Water quality (turbidity, salinity, conductivity, water temperature, and water depth) also was measured. Submerged aquatic vegetation (SAV) biomass and nekton density were measured from April 2005 to September 2005. I monitored paired terraced and unterraced ponds in three sites within Louisiana�s Chenier Plain. Observations and samples were taken in two microhabitat types within ponds: marsh edge and open water. Terracing ponds increased the proportion of marsh edge, but did not alter water quality variables measured. SAV and nekton were denser at the marsh edge than in open water, but did not differ significantly when compared at the whole-pond level between pond types. Waterbirds also were denser at the marsh edge. Waterbird density was consistently greater in terraced ponds. Waterbird species richness was greater in terraced ponds in winter and during spring and summer was generally greater in terraced ponds. Additionally, bird density in ponds varied by foraging guild. During spring and summer, aerialists, shorebirds, and dabbling foragers were consistently denser in terraced ponds. Wading forager densities varied in ponds with time, but were generally denser in terraced ponds. Diving foragers were not dense and did not differ between pond types. During winter, only dabbling and wading foragers were significantly denser in terraced ponds, but these two guilds represented 83% of birds observed. Other foraging group densities did not differ between pond types. Several species of conservation concern were observed. Trends in density for most species of concern were similar to those seen for the foraging guild in which that species was classified. Marsh edge is a biologically prolific habitat. The amount of edge necessary to achieve pond level effects for nekton and SAV has not been evaluated.

Pine plantation forests are increasing in scope across the southeastern United States, particularly Louisiana. These areas provide poor quality bobwhite brood-rearing habitats, and become increasingly degraded without periodic disturbance. Poor quality habitat conditions at a landscape-level scale usually results in reduced fall bobwhite body weights, creating low survival rates. We researched 4 understory vegetation management techniques (ie. mowing, no treatment, burn only, and imazapyr with burning) within pine plantations to evaluate their effects on vegetation composition and structure and on arthropod abundance and availability relative to bobwhite brooding habitat in 2002-2005. We used 1,155 human-imprinted bobwhite chicks to estimate foraging efficiency relative to the various treatments. We assumed that human-imprinted chicks foraged similarly to that of wild chicks, and that they provided a better indicator as to habitat quality in comparison to conventional entomological collection methods (ie. sweepnets and pitfalls). Foraging efficiency of human-imprinted bobwhite chicks was greatest in imazapyr/ burn (RCW) treatments relative to the other treatments. RCW treatments produced vegetation characteristics similar to what could be considered fair brooding habitat relative to the other treatments. Important vegetation characteristics found in RCW treatments were different from the other treatments. Our results suggest that the RCW treatment is more effective at enhancing quality of brooding habitats in degraded pine plantation stands relative to the other treatments. We also used bobwhite whistle counts collected from 2002-2005 to develop a GIS model that assessed landscape features associated with breeding males within a 200m spatial scale. Landscape and class-level habitat variables associated with calling bobwhites were then extrapolated to predict occurrence based on specific habitat features. Our landscape-level analysis determined that the probability of occurrence of bobwhites in an area was related positively to increasing patch diversity, but negatively to the homogeneity of patch types. At the class-level, bobwhite occurrence was positively influenced by increasing amounts of early successional habitat and edge complexity associated with two types of mature pine stands (unburned and RCW treatment). Negative bobwhite abundance was influenced by increasing amounts of 16-25 year old thinned pine plantations, and the amount of variation in patch size of unburned mature pine stands.

Genetic effects influencing salinity tolerance (ST) and cold tolerance (CT) were evaluated in two full diallel mating designs using six tilapia varieties: Oreochromis aureus (BL), O. mossambicus (MO), O. niloticus (NI), O. niloticus crossbreds (RE), Mississippi commercial strain (MC) and Florida red tilapia (FL). Statistical analyses provided estimates of direct heterosis (h_i), cross heterosis (h_ij), maternal effects (m_i), line effects (l_i), reciprocal and specific reciprocal effects (r_ij and r**_ij), and general and specific combining abilities (GCA and S_ij). Analysis of genetic effects for ST indicated that FL exhibited significant GCA (P < 0.01). BL, FL, and MO exhibited highly significant l_i (P < 0.01). Highly significant m_i (P < 0.01) was apparent for FL and RE. Highly significant S_ij and h_ij% (P < 0.01) were exhibited in two and eight variety combinations (VCs), respectively. Highly significant r_ij (P < 0.01) was observed in BL-MO, and MC-RE. In addition, highly significant r**_ij (P < 0.05) was noted in BL-MO and FL-RE. Analysis of genetic effects for CT indicated that BL, MC and RE exhibited significant GCA's (P < 0.05). Highly significant l_i and m_i (P < 0.01) were apparent in BL and RE, respectively. Significantly negative S_ij (P < 0.05) was exhibited only in BLxMC, while negative and significant h_ij% (P < 0.05) was apparent in BLxMC, FLxMO and FLxRE. Highly significant r_ij (P < 0.01) was apparent in FL-MC and MC-RE, while negative and significant r**_ij (P < 0.05) was exhibited only in FL-MC. No significant direct heterosis (h_i) was apparent in ST or CT. Improvement in ST in could be accomplished by developing a breeding program combining selection, hybridization and backcrossing in MO, BL and FL, while improvement of CT may be accomplished by selection and hybridization in BL. The potential environmental and commercial implications of developing salinity-tolerant and cold-tolerant tilapia varieties and crosses are discussed.

Expanding on the Theory of Location, New Economic Geography, and Porter's Theory of Clusters this dissertation attempts to identify key factors influencing the location of firms in a resource-based industry. The softwood lumber industry in the United States is used as a case study to test several hypotheses concerning these theories. Two U.S. regions, the West and the South, were selected for analysis because they account for over 70 percent of U.S lumber manufacturing capacity. A multi-disciplinary research approach involved three-stages. First, self-reported preferences were analyzed using common factor and conjoint analyses for preferences for location attributes. Surveys were sent to all sawmill managers in the U.S. West and South regions. Respondents were identified through the Random Lengths' Big Book (2006), the industry's most comprehensive database. Survey procedures followed Dillman's (2000) Tailored Design Method. Conjoint analysis provided information on the relative importance of selected site attributes using several econometric models to estimate coefficients, significance and marginal effects of site attributes. Second, a model for industry location behavior in the U.S. South was developed using a spatial econometric model. An exploratory analysis identified deviations from complete spatial randomness as first-hand evidence of clustering. The presence of sawmill enterprises was used as the dependent variable, aggregated at the county level. Spatial autoregressive and correlated error econometric models were used to correct for spatial correlation. The final model was used to identify counties where softwood lumber industry development could occur in the future with a high probability of success. Third, two cross-sections of data were analyzed using point density tools to explore spatial concentration in the softwood lumber industry over time. There is evidence of consolidation in the industry as the number of firms has declined while capacity has increased over time. The findings are congruent with spatial predictions drawn by Location Theory, New Economic Geography and to some extent the Theory of Clusters. Research methods used in this study have the ability to capture decision-makers preferences and to operationalize major theories of location, economic geography and cluster development. Results can provide industry and economic development professionals with a new decision-making tool.

The bark of Eucommia ulmoides Oliver (Eucommiaceae) has been used over thousands of years as a folk remedy. Extracts from the bark exhibit multiple pharmacological functions, especially in lowering blood pressure. Geniposidic acid (GA), pinoresinol diglucoside (PG) and chlorogenic acid (CA) are three compounds isolated from the bark of the Eucommia tree, which display enormous bioactivities. As a type of plant tissue culture, the hairy root culture system displays prospective application over traditional cell or callus cultures, which are characterized by rapid growth, and stable biochemical and genetic capacity. The present dissertation discusses the establishment and chemical analysis of E. ulmoides hairy roots. After molecular identification, including PCR and Southern blotting, hairy roots were subjected to various physical and chemical treatments to investigate their impacts on growth and secondary metabolites. Results showed that light, initial pH, and culture volume did not affect the growth remarkably, while medium type, medium strength, sucrose concentration and auxin influenced the growth significantly. Biomass of E. ulmodies hairy roots increased 30% in modified culture conditions. Initial pH only had effect on PG content, while culture volume showed some effect on CA content. Other factors demonstrated varied impacts on content and yield of secondary metabolites. Zero to 50 µM methyl jasmonic acid (MeJA) elicited PG synthesis but inhibited GA production. A low concentration of salicylic acid (SA) reduced secondary metabolic synthesis, while a high concentration of it accelerated the exudation of the metabolites into medium. Exposure to light tended to improve synthesis of secondary metabolites, especially GA and CA. In contrast to other sources of E. ulmoides, hairy roots could synthesize high amounts of secondary metabolites, even specific compounds. In order to increase secondary metabolite production, Vitreoscilla hemoglobin (VHb) was introduced into E. ulmoides hairy root. Molecular characterization, i.e. PCR, Southern blotting and Northern blotting, confirmed the integration and expression of the VHb gene. The transformed hairy root showed improved growth and enhanced synthetic capacity of secondary metabolites. This research will contribute to exploit a new approach to produce PG, GA and CA from the special tissue culture, hairy root culture system.

Over the past 30 years, the king rail (Rallus elegans) has purportedly declined precipitously throughout its range, with the most severe declines seen in the migratory populations. King rails, however, are considered a game species in Louisiana and Texas, thus, it is important to determine what proportion of king rails wintering there are migratory. This is complicated because there is no reliable method to distinguish between king and clapper rails and few studies have attempted to capture wintering rails. The objectives of this study were to: 1) Determine the best method for capturing wintering rails; 2) Determine if morphometric measurements could be used to identify and sex king and clapper rails; 3) Determine the ratio of resident to migrant king rails in southern Louisiana and Texas using stable isotope analysis of feathers. I captured 523 rails, including 187 tentatively identified king rails, 68 tentatively identified clapper rails, 107 Virginia rails, 123 sora, and 38 yellow rails. The effectiveness of capture techniques were: 1) drop-door traps with drift fencing - 0.0063 rails per trap hour, 2) capturing by hand or net from an airboat at night - 2.13 rails per hour, and 3) capturing by hand or net from an ATV at night - 1.80 rails per hour. Discriminate analysis of morphometric measurements revealed that wing, tarsus and culmen measurements could be used to differentiate between king and clapper rails. Multiple stable isotope analysis of rail feathers, äD, ä13C, ä15N, and ä34S, showed distinct differences among winter collected king rails and known migrants, but did not show differences between the winter collected king rails and residents. This indicates that most, if not all, of the winter collected king rails were resident to Louisiana and Texas. A linear relationship was seen between äDf values and estimated äDp values at the collection locations (r2 = 0.42). The fractionation factor that resulted from this analysis could be used to determine an approximate breeding location for the winter collected rails, and also indicated that most, 99%, of the winter collected king rails were resident to Louisiana and Texas.

Landscape change throughout North America has resulted in heightened nest predator population and declining avian productivity. Essential to establishing effective management design is an understanding of differential predation pressure among avian groups as group specific responses to predation impact may exist. The objective of this study was to examine the efficacy of predator trapping on the nest success and density of ground nesting avifauna in 2004-2005 in the Virginia Coast Reserve, specifically dabbling ducks, Canada Goose and Willet. Second, we determine the impact of predation on ground nesting birds by relating indices of predator abundance to nest density and nest success for island plots. Overall Mayfield nest success for dabbling ducks was 54.4% (n = 12) in 2004 and 17.7% (n = 30) in 2005. Green Transformed nest success for dabbling ducks was 34.5% (n = 25) in 2004 and 23.0% (n = 42). For Canada goose, overall Mayfield nest success was 53.1 (n = 37) in 2004 and 47.7% (n = 39) in 2005. Overall Green Transformed nest success for Canada Goose was 59.5% (n = 57) in 2004 and 50.6% (n = 51) in 2005. Finally, overall Green Transformed nest success for Willet was 53.7% (n = 110) in 2004 and 46.0% (n = 118) in 2005. Nest success estimates on island plots varied greatly. There was no difference in nest success between trapped and non-trapped islands for dabbling ducks (P = 0.1990), Canada Goose (P = 0.4860), Willet (P = 0.4920) and artificial nest success (P = 0.4200). Likewise, there was no difference in nest density between trapped and non-trapped islands for dabbling ducks (P = 0.2408), Canada Goose (P = 0.2950), and Willet (P = 0.1381). Several factors may explain this result including a lack of trapping efficacy, design flaws, low intensity of trapping, and differences in island habitat affecting avian nest site selection and sample size. Nest success for both dabbling ducks (P = 0.0225) and Willets (P < 0.0001) was inversely related to predator activity, as measured by artificial nest success. In contrast, Canada Goose (P = 0.6686) showed no relationship between nest success and predator activity. For Canada Goose (P = 0.0064) and Willet (P = 0.0029), nest density decreased with increasing predator activity on island plots. Biased nest detection, philopatry to islands with reduced predation risk, and active selection for reduced predator environments may explain the higher nest density on islands with reduced predator activity. On barrier islands in Virginia, dabbling duck nest densities are independent of predator activity (P = 0.1981). I hypothesize that, in this system, the availability of brood rearing habitat for ducks govern island selection above predation risk.

I compared nest success estimates for both shorebirds and Sharp-tailed Grouse between controls and 36 square-mile blocks that were trapped for intermediate mammalian predators. I also investigated shorebird nest site selection by comparing vegetation visual obstruction and species composition between nest sites and the surrounding field. Nest success (Mayfield estimate ± SE) was not different between trapped and control blocks for shorebirds (trap: 50.8% ± 6.3%; control: 69.1% ± 17.5%) or Sharp-tailed Grouse (trap: 61.3% ± 8.3%; control: 48.7% ± 10.0%). This indicates that trapping intermediate mammalian predators is not an efficient method of increasing shorebird or Sharp-tailed Grouse nest success. Regardless of the surrounding habitat type, shorebird nest sites were located in characteristic vegetation depending on species. Common Snipe preferred nest sites to be covered by native vegetation that obstructed vision below 21cm. Wilsons Phalarope also preferred native vegetation, however they nested in vegetation obstructing vision less than 16cm. Upland Sandpipers showed little preference for vegetation species composition, although nest sites were typically found in vegetation obstructing vision less than 21cm. These results indicate that useful shorebird habitat includes relatively sparse, native vegetation.

In the southeastern United States, industrial agriculture dominates the landscape, and much of the native land cover is in decline. Longleaf pine forests were once a dominant ecosystem in this region, but have largely disappeared. However, little research has been conducted on how this loss affects wildlife, especially mammalian predators. With increasing restoration efforts for longleaf pine it is important to assess the impact on species that inhabit those landscapes. Gray foxes (Urocyon cinereoargenteus) are native to the Southeast, but are adaptable to a wide range of habitats. Therefore, during 2002-2006 I studied a population of gray foxes on land managed for longleaf pine (Ichauway plantation) and the surrounding agriculture and residential landscape. Gray fox habitat selection did not differ across seasons (P > 0.050) at any of the 3 spatial scales examined, but was non random at all scales (P ≤ 0.050). Gray foxes preferred habitat types that were rare or not available on Ichauway including residential areas, hardwood forests, and industrial agriculture. Gray foxes were largely found partially or completely off Ichauway. In fact, gray foxes that overlapped Ichauway were found closer (Λ = 12.06, P < 0.001) to the borders of Ichauway than expected. Annual survival was 0.610 ± 0.100. Sixteen deaths were documented, and human causes (i.e., vehicle collisions) accounted for most (n=10) of these. Gray fox mortality from human caused sources may have been higher than in most other populations because of the selection of anthropogenic habitat and lack of trapping. Home range sizes differed between seasons (F2,34 = 3.97, P = 0.030), with home ranges in winter (152.43 ± 32.02 ha) being larger than either breeding (91.42 ± 12.93 ha) or kit-rearing (99.68 ± 18.27 ha) seasons. Grafens kinship coefficient was used to examine relatedness through genetic analysis. No correlation was detected between distance of trapped gray foxes with one another and their genetic distance for either 2004-2005 or 2005-2006 (P > 0.1). Preliminary evidence suggested that closer relatives may be more apt to overlap one anothers spatial use area.

This dissertation addresses applying industrial park concepts to the development of aquaculture parks in public waters specifically for off-bottom triploid Easter oyster, Crassostrea virginica, culture. The objectives are to identify the permitting process, relevant agencies, and legislation needed to facilitate development of aquaculture parks in the Gulf of Mexico states, and test and analyze off-bottom oyster culture for commercial production of triploid oysters. Off-bottom culture can increase oyster production, but fouling organisms can reduce growth and survival rates. The Adjustable Longline System (ALS), commercially used in Australia, allows oyster bags to be suspended in the water column and positioned for aerial drying to deter fouling. This study evaluates means of controlling fouling organisms for off-bottom culture of diploid oysters by measuring 1) growth rate, 2) survival rate, and 3) fouling rates. This study shows that routine aerial exposure reduces the amount of fouling organisms without significantly affecting growth or survival. The oysters in all treatments reached market-size in twelve months and had survival rates greater than 80%. Advances in oyster genetics research are creating superior candidates for culture and needs to be coupled with advanced grow-out methods to reach full potential. Triploid oyster culture is a viable alternative to natural oyster production but requires investment in seed. This study analyzed the capital, operating costs, and break-even prices of a 0.40-hectare ALS for triploid oyster culture. The analysis assumes that seed is purchased from a hatchery and that the culturist harvests triploid oysters during the months when on-bottom oysters have a lower meat yield. The break-even costs are determined for a 100-count box of oysters. Once importation and permitting costs are determined, areas of the budget can then be adjusted to reduce the break-even price. This will include such factors as domestic system components, labor hours, or stocking density. The results will determine if off-bottom culture of triploid oysters is a good investment for the Louisiana oyster industry. In addition, an operational plan was also prepared for the ALS to meet the International Shellfish Sanitation Council requirements for shellfish culture facilities.