The alligator gar Atractosteus spatula is a large, long-lived, physostomous fish that inhabits aquatic habitats throughout the central U.S., ranging from Oklahoma southward to the Gulf of Mexico. Unfortunately, the alligator gar has declined significantly in abundance throughout much of its historic range and is now considered vulnerable to localized extirpation. The goal of this study was to provide basic data on the ecology and life history of a commercially-exploited alligator gar population in south Louisiana. This study also focused on age determination and alternate aging techniques such as sectioned otoliths and sectioned scales. From 10 April 2007 through 21 May 2008, alligator gar were collected with jug lines from Bayou DuLarge and surrounding areas with the aid of a local commercial fisher. A total of 203 male, 125 female and 1 unsexed alligator gar were collected. Sex ratio was approximately 1:1 for catch by month. Overall, female alligator gar were longer, heavier, and had larger girths than males. Alligator gar predominately fed on fishes (34%), although crustaceans (4%) and non-food items (5%) were also found. Based on gonadosomatic index values, spawning occurred from March through May. Gar ages ranged from 1 to 26 years with a mean age of 5 years for males based on sectioned otoliths (N = 194) and sectioned scales (N = 144). Mean age for females based on sectioned otoliths (N = 122) was 5.5 years, and 5.8 years based on sectioned scales (N = 71). In my sample, it appeared male and female alligator gar matured by age 5. The growth rate (k value from von Bertalanffy growth equation) was 0.323 ± 0.017, and annual survival from a catch curve was estimated to be 79.9% (Z = 0.225). Sectioned otoliths yielded the highest precision between readers (0.46, Average Percent Error) and presented fewer complications during age determination as compared to sectioned scales. Life history and age information from this study will aid with understanding the complex and variable nature of the Bayou DuLarge alligator gar population and will be useful to agencies in the development of future management programs for this unique species.

Colonization of natural areas by Chinese privet (Ligustrum sinense Lour.) threatens biodiversity and preservation of native habitat in the southeastern United States. High rates of seed production and dispersal, coupled with clonal growth, result in a competitive advantage when introduced to novel areas. Land managers have attempted to control L. sinense through prolonged flooding, prescribed fire, and herbicide application with little success. I determined presence of L. sinense invasion in four sites in Louisiana and assessed key reproductive, growth, and survivorship characteristics defining its life course. I used vegetation surveys, germination trials, dendrochronology, and demographic models to elucidate stages in L. sinenses life cycle that contribute most to population growth. Populations of L. sinense have the potential for rapid growth. I germinated seeds under growth chamber, greenhouse, and field conditions. Stage-based matrix projection models showed the finite rate of population increase (λ) ranged from 1.48 in the field to 2.26 in the growth chamber. I used elasticity analysis to identify the proportional contribution of remaining in a stage (P), growing to a subsequent stage (G), and fecundity (F) to population growth, and perturbed matrices to mimic management strategies. A 50% reduction in PSEEDLING, PJUVENILE, and PSMALL ADULT reduced λ to 1.66 in the growth chamber and 1.63 in the greenhouse. Under field conditions, a 50% reduction in all Pi was required to bring λ to 1, so that populations were stationary. Reductions in FADULT did not immediately cause a decline in population growth. Approaches that target multiple life stages may be more successful for managing L. sinense. Using field germination rates, reduction of FLARGE ADULT by 50%, plus a 50% reduction of GSEEDLING and GJUVENILE, and PSMALL ADULT and PLARGE ADULT made population growth stationary (λ = 1.04). Management techniques that increase annual mortality of specific life stages may be more cost effective than targeting all individuals within a population. This study has identified transitions that contribute most to population growth over a range of growing conditions and indicated management options that may streamline control of this invasive plant.

The aqueous leaf extract of Rubus suavissimus (Chinese sweet leaf tea) was active in inhibiting angiogenesis, which could be used to suppress adipogenesis and cause weight loss. Following this revelation and approach, the anti-obesity effect was thoroughly investigated in normal and obese rat models. The investigations began with the preparation of quality-controlled extract. First, the crude extraction methods were examined leading to the characterization of the chemical composition. Second, the impure components were removed by alcohol precipitation and column chromatography, resulting in a standardized sweet leaf tea extract (RUS). Third, three bioavailable compounds identified from the urine analyses were re-constituted to form the purified sweet leaf tea extract (GER), which accounted for 27% by weight of the RUS. These standardized and purified sweet leaf tea extracts were then evaluated for their anti-obesity effect in normal and obese-prone rats. Both RUS and GER reduced body weight gain by 7% (p =0.999) in normal rodents but statistical analyses failed to show any significance due to small sample size. Amazingly, it was discovered that the use of the tri-compounds combination (GER) produced the same anti-obesity effect as the standardized extract (RUS). Consequently, new experiments were focused on the GER using obese-prone rats as the study model. GER showed a significant anti-obesity effect by reducing 22% (p¡Ü 0.001) weight gain compared to the high-fat diet control group. Total abdominal fat was reduced significantly by 48%, indicating that the lost body mass was mainly due to the loss of body fat. Other benefits of the Chinese sweet leaf tea extract included lowered blood glucose, cholesterol, and triglycerides. Food intake was not affected. No adverse effects were observed. This research provides exciting insights about the novel use of the Chinese sweet leaf tea as a safe and effective anti-obesity agent beyond its historic use as a natural sweetener. Human clinical investigations are strongly warranted to determine the effective doses and long-term use safety in combating obesity or managing body weight.

Forestry is a major contributor to the Ghanaian economy and has the potential to increase its contribution if a number of challenges are overcome. Over the past 15 years, Ghana has modified its forest policies, laws, and regulations, but still faces serious challenges with illegal logging and unsustainable forest management. At the same time, Ghanas major wood product trading partner, the European Union (EU), is requesting that Ghana, under the Voluntary Partnership Agreement (VPA), ensures that wood products from Ghana to the EU are legally produced. Additionally, several EU wood product importers have requested their suppliers in Ghana to meet certification requirements. To date, efforts by Ghanaian companies to achieve certification have not been successful. Certification can potentially address forest management challenges facing tropical countries like Ghana, while enhancing the export of wood products to environmentally sensitive markets, such as the EU. This research was conducted to identify the underlying causes for Ghanaian companies inability to meet certification requirements and the implications for forest management and timber exports from Ghana. The research was conducted in Ghana from May to August 2009. Mail surveys supported by field assessment of forest management practices were the main research methods used. In addition, interviews were conducted with key contacts from the four groups studied: policymakers, loggers, wood processors/exporters, and wood product importers from Ghana. Results suggest that current forest management practices in Ghana are unsustainable. Forest management certification was found to have a positive impact on forest management, but is unlikely to be an effective mechanism in influencing overall forest management practices. Respondents identified illegal logging, corruption, and weak enforcement of forest laws as the key impediments to sustainable forestry in Ghana. In spite of the increasing demand for certified wood products by European importers, results indicate that Europe is the primary destination for respondent wood exports. The most significant conclusion is that the government should undertake institutional roles reform to transfer key forest management functions to companies that adhere to government standards, while addressing the underlying factors of corruption, illegal logging, and weak enforcement of forest laws through a broader stakeholder consultative process.

The effects of bait type, trap-soak duration, and a trap entrance modification were evaluated from February through May 2008 in a 1.29 ha crawfish (red swamp crawfish, Procambarus clarkii) pond in southwest Louisiana. Commercial pyramid traps with three entrance funnels, 1.9-cm square-mesh vinyl-coated welded metal wire, were used. In trial 1, crawfish catch was evaluated in traps baited with Atlantic menhaden (Brevoortia tyrannus), a formulated dry bait, or a menhaden+formulated bait mixture, each at 24-h and 48-h soak durations. In trial 2, the escape of marked crawfish was evaluated in the presence or absence of bait at 24-h and 48-h soak durations. In trial 3, the catchability of traps with modified entrances, designed to reduce crawfish escape, were evaluated at 24-h and 48-h trap-soak durations. In trial 1, menhaden alone was the most effective bait in February and March, all baits were equally effective in April, and the formulated bait alone was most effective in May. Overall, crawfish catch per unit effort (CPUE) with a 24-h soak duration was 36% and 27% higher in number and weight than the 48-h soak. Mean crawfish size increased when trap-soak duration was increased from 24-h to 48-h. In trial 2, traps containing no marked crawfish caught significantly more crawfish in both number (37%) and weight (30%) than traps with marked crawfish indicating that the presence of crawfish in traps prior to baiting decreased catch. Mean crawfish escape from traps ranged from 29 to 34%, and the presence or absence of bait had no significant effect on escape; however, the mean escape rate following a 48-h trap-soak duration (39%) was nearly twice that of a 24-h soak (22%). Crawfish CPUE with modified traps was 20% higher with a 48-h trap-soak duration. Modification of the trap entrance funnels with plastic cable ties appeared to reduce the rate of crawfish egress from the traps between 24-h and 48-h.

This dissertation research aimed to quantify current soil organic carbon (SOC) stocks across Louisianas landscape, examine the spatial relationships between SOC and terrain factors at the watershed and river basin scales, and predict SOC changes in surface soils during future climate change. Using Louisiana as an example, a spatially-explicit modeling framework was developed that is conducive to watershed-scale prediction of soil carbon stock and change. SOC densities at the watershed scale were estimated using the USDA NRCS Soil Geographic Database (STATSGO). Louisiana watersheds and National Land Cover Database (NLCD) were used to aggregate total soil carbon and estimate average soil carbon density. Watershed drainage densities and slopes were quantified with 1:24 K Digital Elevation Models (DEM) data and the Louisiana hydrographic water features. Potential changes in SOC under 0.5° x 0.5° high-resolution climate change projections in Louisiana were simulated using a RothC model at a watershed scale under three greenhouse gas emissions scenarios (A1FI, A2, B2) based on the HadCM3 climate model. LIDAR and DEM datasets were used to assess the spatial distribution of potential inundated coastal areas; estimate the current wetland areas, SOC storage, and nitrogen contents at risk in Louisiana, classified by the National Wetlands Inventory (NWI) and DEM datasets. The research found that SOC density ranged from 22 to 108 tons/ha in the upper 30-cm soil at the watershed scale, with the highest density in emergent herbaceous wetlands. Among Louisianas 12 river basins, the Barataria, Terrebonne, and Lake Pontchartrain Basins in southeast Louisiana showed the highest SOC density. SOC density was positively correlated with watershed drainage density (r2=0.43), but negatively correlated with watershed slope gradient (r2=0.52) and elevation (r2=0.50). The modeling study on climate change effects showed that SOC storage in the top 30-cm soil layer of Louisiana forests, croplands, and grasslands would significantly decrease under all climate change scenarios. Coastal areas in southeastern Louisiana have some freshwater and estuarine wetland ecosystems that store a large quantity of organic carbon. Much of these areas have elevations less than 100 centimeters and are, therefore, prone to inundation of sea level rises during future climate change.

Recovery of heavy metals from chromated copper arsenate (CCA) treated southern pine wood samples with three different dimension was investigated by recovery with acetic acid, oxalic acid and phosphoric acid in microwave reactor. Diluted phosphoric acid mixed with acetic acid was found to be very effective to remove copper, chromium, and arsenic from spent CCA-treated southern pine sawdust at a high temperature and in a short time. No single acid can totally recover all these three metals in one step in this method. Oxalic acid was effective in removing chromium and arsenic, and acetic acid was effective in removing copper and arsenic; However, CCA cannot be recovered with the mixture of acetic acid and oxalic acid because of a possible conflict effect. The effects of mixed acid concentration, reaction time, and temperature in microwave on recovery of CCA-treated wood samples were determined. The minimal reaction condition for maximum extracting CCA elements was 2.75% phosphoric acid mixed with 0.5% acetic acid, for 10min. at 130°C. The total recovery rate of CCA can reach 100% arsenic, 93.5% chromium, and 98.5% copper in one step. Statistical analysis showed the concentration of phosphoric acid and temperatures were two important factors. Three sizes of wood chips were also extracted in the microwave reactor. For the particle size of 0.5×0.5×0.5cm, 93.5% arsenic, 64.5% chromium, and 95.89% copper was extracted by 3.5% phosphoric acid mixed with 0.5% oxalic acid after 50 min at 130°C. Although it needs a longer time to achieve the total CCA extraction, the microwave reactor assisted acid extraction method was more effective than previous approaches.

Water chemistry, habitat quality, and channel stability interact to influence a streams biological integrity. The goal of this project was to assess how channel stability, together with other physicochemical stream measurements, are associated with the structure and abundance of resident macroinvertebrate communities. I recorded multiple physicochemical parameters and calculated a Pfankuch habitat stability index monthly for a year at potential reference streams in southeastern Louisiana. I assessed the relationships of channels stability with measured physicochemical parameters with multiple regression and principle components analysis. Mixed model multivariate analysis of variance was used to determine associations of habitat characteristics with resident macroinvertebrate genera and communities. In the September woody debris sample, macroinvertebrate abundance was generally determined by habitat factors that describe stream metabolism and woody debris habitat, in the May woody debris sample, abundances of xylophilic macroinvertebrates appeared to be more associated with geomorphologic components of a stream rather than stream productivity. The PSI was associated with multiple habitat variables, and variability in channel stability between streams was found to affect macroinvertebrate genera and community abundances in both seasons regardless of stream size or stream productivity. Because of the high correlations between the PSI, other habitat variables, and macroinvertebrate abundance, I believe the PSI should be used in future studies that focus on developing a biotic index in low gradient Louisiana streams. Integrating biological monitoring, more precise habitat measurements, and current physicochemical monitoring protocols will result in managers having more tools to evaluate stream degradation and protect Louisianas waterways.

In riverine wetlands, the rate and magnitude of water exchanged between river channels and adjacent wetlands have a major influence on hydrologic function and associated aquatic habitat and water quality. River channels are generally separated from backswamps by natural levees; however, preferential flow may allow potentially substantial water and solute exchange between them. Determining the influence of preferential flow on water and solute transport in natural levees requires an innovative approach that allows measurement of transport rates at a scale large enough to capture field-scale variability. To test the hypothesis that preferential flow is important to subsurface water movement through natural levees, we measured hydraulic gradients and solute tracers in a 10 x 9 m grid of 19 shallow (2m) monitoring wells within a large volume (300 m3) of natural levee in the Atchafalaya Basin, Louisiana. In addition to measuring transient responses to natural events, we constructed a small reservoir on the backswamp side of the levee to create a hydraulic gradient from the swamp to the adjacent river channel. We used a simple linear system approach to model residence time distributions of water and solute within the natural levee. Overall, hydraulic response to forcing events, whether from rain or reservoir filling, was rapid in all wells (mean pressure wave velocity 2.5 E-2 m/s) and relatively uniform; in comparison, tracer transport was much slower (mean 3.2 E-4 m/s) and more variable. Spatially, mean subsurface tracer velocities varied over several orders of magnitude: between 1.6 E-7 and 6.8 E-5 m/s under a 12-cm hydraulic gradient and between 2.1 E-7 and 2.2 E-3 m/s under a 70-cm hydraulic gradient. Comparatively greater variability of chemical verses hydraulic behavior indicates multiple functioning transport mechanisms in natural levee sediments and suggests preferential flow; thus, methods that estimate transport rates based on standard point measurements likely greatly underestimate exchange at the field scale. Results suggest that preferential, subsurface flow through natural levees may provide hydrologic connectivity that is meaningful to basin-scale biogeochemical processes.

North American grassland birds have been declining at an alarming rate. Winter habitat for grassland species in the southeastern U.S. generally occurs within forests subject to management. I studied wintering grassland bird communities in De Soto National Forest in southern Mississippi. My objectives were to: 1) Assess bird communities and vegetation structure in upland forest stands that were salvage-logged following Hurricane Katrina, in stands managed for Red-cockaded Woodpeckers (Picoides borealis, RCW), and in stands containing bogs; and 2) Determine the extent of the association between vegetation and occurrence of the common wintering grassland birds. I conducted bird and vegetation surveys in 27 stands over two winters. The wintering grassland bird community included Bachmans Sparrow (Aimophila aestivalis), Henslows Sparrow (Ammodramus henslowii), and Sedge Wren (Cistothorus platensis). Forest-stand associations varied among species. Bachmans Sparrows occurred only in upland and RCW-managed stands, Henslows Sparrows occurred only in bogs and RCW-managed stands, and Sedge Wren occurred in all stand types. None of these species densities was statistically different between salvaged and unsalvaged stands. There were no statistically significant differences in total grassland bird density or species richness among stand types. Henslows Sparrow use of RCW stands was mostly ephemeral, but our data were consistent with previous studies suggesting that RCW management benefits grassland birds. Spatially uniform, dense herbaceous cover, and cover of Scleria muhlenbergii, a preferred food item, best predicted Henslows Sparrow stand occupancy. Increased woody understorey vegetation and decreased tree density best predicted Sedge Wren occupancy. I recommend management practices focusing on small-scale herbaceous ground-layer restoration in bogs, an increase in the number of RCW clusters, and the thinning of trees in dense stands.