Modified river flows and land subsidence have subjected many coastal swamp forests in the delta of the Mississippi River to greatly altered flooding, sediment, and nutrient regimes. These areas have become inundated to greater depth, duration, and frequency and either are connected to the river and receive drastically increased sediment and nutrients (riverine swamps) or have become disconnected from riverine flooding (stagnant swamps) and receive little or no sediment and nutrient input. To better understand how these changes are affecting ecosystems, dendrochronological techniques for baldcypress (Taxodium distichum L. Rich.) were used at three sites in each of two contrasting swamps to compare how productivity has been historically related to climate and hydrology. The historical responses of baldcypress radial growth to 111 years of climatic variables and 51 years of hydrological data were analyzed by separate and simultaneous multiple linear regression analysis of effects. The effect of flooding on growth of baldcypress depended on the temporal scale and type of floodwater. Seasonal flooding increased growth in flood years for both stagnant and riverine swamps but decreased growth in the ensuing year. Long-term, riverine flooding was positively correlated to growth, but long-term, stagnant flooding was negatively correlated to growth. Growth in both swamps increased at onset of greater flooding, then decreased after several decades of continued frequent flooding. Climatic controls on growth depended upon interactions with hydrology but correlations between growth and flooding variables were consistent and much stronger than climate. When climate was analyzed separately, warm winters and cool, rainy growing seasons were important for higher growth. When hydrology was included in simultaneous analysis with climate, cool, dry fall weather of the previous year was also important. A model of baldcypress growth that only includes hydrologic regime is insufficient to understand growth. Climate, stand history, hydrological regime and the interaction of these effects must be considered to accurately understand changes in growth.

Hurricanes Katrina and Rita made landfall in southern Louisiana during August and September 2005, respectively. Prior to these storms swamp tours were a popular nature-based tourism experience that entertained visitors while teaching them about local flora, fauna, and culture. The number of swamp tour businesses in the state was slowly increasing. The purpose of this study was to determine how many swamp tours were operating after the hurricanes, what type of damage they sustained, and how they repaired their businesses. Differences between those tours that remained open after the hurricanes and those that closed were also examined. A 3-phase mail survey was used to collect data throughout the winter and spring 2006 with a response rate of 74%. Respondents included 22 open businesses and nine closed businesses, seven of which planned to re-open eventually. The most common damages reported were loss of telephone service and damage to the swamp. Fewer tourists were also a problem for swamp tours, as 72% reported business was much lower than before the storms. Significantly more swamp tour businesses that had been operating for more than 15 years remained open after the storms than those businesses operating for less than 15 years. Swamp tour businesses in Louisiana were primarily family owned and employed fewer than five people. The majority of swamp tour owners believed their businesses were important to both the state tourism industry and the local economy of their area. This study also found that a new type of tour, the New Orleans disaster tour, was offered by four businesses that conduct swamp tours. A follow up survey after a period of one or more years is suggested to determine if the number of fully operational swamp tour businesses in the state has increased and detect any changes in the number of tourists in the area.

Considerable research has been conducted to evaluate the adoption of agricultural best management practices and their overall impact on improving environmental quality. However, limited studies have been conducted to evaluate the behavioral factors that influence the adoption of these practices in the context of educational programs The goal of this study is to determine the factors that influence farmer conservation behavior that might lead to an increased probability of improving agriculture and forestry watersheds. A conceptual model was developed to identify the: 1) identify landowner participation in watershed conservation projects, and 2) determine the factors influencing agriculture and forestry landowners to participate in watershed conservation projects. The model includes four major sets of explanatory variables including: 1) social-psychological, 2) farm structural, 3) ecological, and 4) institutional. This study indicates that both farmers and loggers that are younger, more educated and of Caucasian ethnicity tend to participate in environmental stewardship programs which lead to the implementation of conservation practices. Farmers with strong local organization relationships have a greater tendency to participate in environmental stewardship programs which leads to the adoption of conservation practices. Agricultural producers with higher income resulting from farming, higher total acres, and farms legal structure indicated as incorporated tended to participate in environmental stewardship programs. Loggers that produced larger loads per week, which is an indicator of size, tended to participate in environmental stewardship programs. The study also found that agricultural producers who spend more time in a job off-farm and have a family owned operation have a lower tendency to participate in environmental stewardship programs. The study indicates that farmers that have modified their operation due to the Clean Water Act as well as awareness of efforts to control non-point source pollution through the Clean Water Act have a lower tendency to participate in environmental stewardship programs, thus viewed upon as institutional barriers. Also found was loggers with negative relationships toward regulatory agencies and lending institutions have a lower tendency to participate in environmental stewardship programs. Farmers have mixed attitudes toward government involvement in agriculture. These conclusions are supported by earlier studies.

Land for forest plantations is declining while demand for forest products is increasing, creating concern over sustainable forest management. Maintenance of site productivity is fundamental to forest sustainability, and an assessment of cumulative height growth is a useful index of productivity. Loblolly pine height data were used from four research plantations installed by the project Cooperative Research in Sustainable Silviculture and Soil Productivity from Texas to Georgia. The sites vary in soil characteristics, management history, nutrient status at time of planting, and age (from 4 to 9 years). Each site is a randomized complete block design with a factorial treatment arrangement of harvesting practices (minimum and maximum disturbance) and different establishment practices (e.g., bedding, fertilization, herbaceous weed control, herbaceous weed control plus fertilizer, and burning). An integrated statistical analysis using the change in height with age was used for the evaluation of longer-term treatment effects. Harvesting practices had a significant treatment effect on the change in height with age (p < 0.03) at one site, but did not significantly affect early height growth at the other three sites (p > 0.37). On the other hand, establishment practices had a significant effect on the change in height with age (p < 0.01), independent of accompanying harvesting practice.

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.