Juvenile (4 g) tilapia of four varieties, Nile tilapia (Oreochromis niloticus), blue tilapia (O. aureus), Florida red tilapia (O. urolepis hornorum x O. mossambicus), and Mississippi commercial tilapia (Oreochromis spp.) were tested for salinity tolerance. This was accomplished by subjecting them to four salinity regimes during a 97-h period with as long as 63 h acclimation. Salinity regimes represented salinities found along coastal Louisiana. Each variety was challenged individually against every other variety and thus in triplicate. All four varieties are commercially produced in the southeastern United States. The Florida red tilapia and Mississippi commercial tilapia are hybrid-based varieties (distinct species were crossed to produce their lineages). Juvenile O. aureus, O. niloticus, and Florida red tilapia exhibited good survival (> 81%) in salinity regimes up to 20 ppt, with moderate survival of O. aureus (54%) and Florida red tilapia (33%) at 35 ppt salinity. Mississippi commercial tilapia survived salinity regimes up to 10 ppt and exhibited poor survival at 20 ppt (5%). The potential for acclimation and survival of juvenile tilapia in Louisianas coastal aquatic habitats was evaluated based on a comparison of trial results with prevailing seasonal salinities in coastal waters. The study indicated O. aureus, O. niloticus, and Florida red tilapia could survive salinities throughout the year along coastal Louisiana. These results will allow Louisiana and other Gulf of Mexico states to more objectively evaluate risks associated with tilapia production in coastal watersheds by quantifying the salinity tolerances of two commercially important hybrid-based tilapia strains.

Reducing predator populations in the prairie pothole region can greatly increase nest success of both over water and upland nesting ducks. However, little is understood about impacts of predator removal on other wildlife within the same area. I conducted a field experiment to test whether small mammals, primarily mice (Peromyscus sp.) and voles (Microtus sp.), responded to seasonally reduced predator abundance. I compared small mammal abundance on 10 experimental (259 ha) sites in North Dakota during 2001 and 2002 with intensive, seasonal predator trapping with 10 control sites (259 ha) also monitored in both years. Small mammals were more abundant on sites where predators had been removed (F_3,132= 44.45, P<0.001), suggesting that small mammals responded numerically to an absence of medium-sized carnivores. However, levels of small mammals were comparable in both springs, suggesting that enlarged populations of rodents in summer and early fall were not sustained through winter. I also observed a strong positive relationship between small mammal abundance and duck nest success (r = 0.84, P = 0.002 in 2001; r= 0.82, P = 0.004 in 2002), suggesting a possible buffer effect small mammals may have on predation of waterfowl nest.

The extracts of many plants used in traditional medicine contain curative agents that are used in many modern medicines. As part of the quest for potentially valuable plants of medicinal value, the plant species Phyllanthus amarus Schum. and Thonn. and Quassia amara L. were chosen based on ethno-pharmacological knowledge from Suriname, South America. Phyllanthus amarus (whole plant) was collected in the city Paramaribo and in the country, and Quassia amara (wood) was collected in the countryside of Suriname. The aim of this study was to optimize extraction methods in order to maximize the recovery of secondary metabolites in the crude extracts of P. amarus and Q. amara. This was accomplished by examining the influence of different extraction solvents on the presence of secondary metabolites in the extracts by thin layer chromatography (TLC), determining the most suitable mobile phase for the plant extracts, and determining the most suitable detection method. Ten grams of each species were extracted (w/v 1:10) with 50% methanol in water, 99% methanol, and 50% methanol in chloroform. Thin layer chromatography (TLC) was used to analyze the compounds in the plant extracts. In order to detect the most compounds, it was necessary to determine the optimal mobile phase (chloroform/methanol 9:1; 95:5; or 98:2) and most suitable detection method (I: UV-254 nm and Phosphomolybdic acid reagent; II: UV-365 nm and Dragendorff reagent; III: ethanolic sulfuric acid reagent; or IV: ethanolic sulfuric acid and UV-365 nm). For both plant species, crude extracts from methanol and chloroform-methanol yielded the highest number of fractions. Mobile phase chloroform/methanol 95:5 eluted the most fractions and had the best separation. Detection method I detected a wide variety of fractions/compounds. In the P. amarus extracts the following secondary metabolites were visualized: alkaloids, flavonoids, lignans, phenols and indole derivatives. In Q. amara extracts, alkaloids (e.g. β-carbolines, canthin-6-ones) and quassinoids were detected. Methanol as an extraction solvent gave the best recovery (extraction rate) of secondary metabolites in both plants, and it can be concluded that different extraction solvents influence the extraction rate. Optimized powder extracts were produced as determined by TLC analysis for future bioassay tests.

Marsh terracing and coconut fiber mats are two restoration techniques currently being implemented at Sabine National Wildlife Refuge. We tested two hypotheses related to these restoration techniques: (1) marsh terracing enhances nekton assemblages, so that nekton use is similar to those at natural marsh edges, and (2) coconut matted marsh edges enhance SAV recruitment, so that nekton use is similar to those found at natural marsh edges. Samples from terraces and coconut matted marsh were compared to samples from the natural marsh and open water habitats. We measured the following variables at each habitat: (1) nekton density and abundance, (2) nekton biomass, (3) nekton size, (4) nekton diversity, and (5) nekton species composition. Using a collapsible throw trap with 3 mm mesh and a 3 x 2 m straight seine, 180 nekton samples were collected at four sampling dates from winter 2001 to fall 2002. Six habitat types were sampled: (1) natural marsh edge (< 1 m from marsh - water interface), (2) coconut matted marsh edge, (3) terrace edge, and (4), (5), (6) open water (50 m from marsh - water interface for all 3 edge types). Environmental variables that may be influenced by restoration status were also monitored at each habitat. Samples from terraces and coconut matted marsh were compared to samples from the natural marsh edge and open water habitat. Results indicated that nekton variables at coconut matted edge and open water, natural edge, and terrace edge were not significantly different (p > 0.332). Nekton density, biomass, and diversity were lower in open water habitats associated with natural marsh and terraces than in the other four habitats (p < 0.0001). Coconut matted and natural marsh edges had significantly higher numbers of some benthic dwelling species (e.g. blue crab Callinectes sapidus, white shrimp Litopaenaus setiferous, naked goby Gobiosoma bosc, clown goby Microgobius gulosus, Gulf pipefish Syngnathus scovelli) than terrace marsh edges (p < 0.0004), potentially due to differences in substrate caused by construction of the terraces. Researchers have suggested that decreased benthic habitat quality at dredged material marshes is related to an impaired infaunal community and differences in sediment texture. At Sabine NWR, terracing and coconut matting increased nekton utilization 4.5 times above that in open water habitat by enhancing and increasing marsh edge relative to open water. The value of terrace and coconut matted marsh habitat for individual species may vary depending on their niche requirements. Future research on terrace success at providing nekton habitat should address nekton growth rates and correlate nekton composition to the infaunal community.

Black bears (Ursus americanus) historically occurred throughout much of North Americas forested landscapes, but loss of critical habitat and overharvest significantly reduced abundance and distribution. In the southeastern United States, black bear conservation has become a high priority and restoration has been suggested y to recolonize suitable habitat. My study focused on evaluating restoration of the Louisiana black bear (U. americanus luteolus) to the Red River Complex (RRC) in east-central Louisiana. This involved translocating female bears with new born cubs from source populations within Louisiana and monitoring their movements, habitat use, and social acceptance of the restoration program to determine if restoration attempts should be continued. Females relocated using this method had restricted home ranges and movements during the initial 30-days following release, and established home ranges at the release site within 7 months. Females continued to den in the area they established home ranges through the following 2 winters. Vegetation measurements at used locations suggest that habitat suitability in the RRC similar to other areas considered highly suitable for bears in the Southeast. A survey of hunters within the RRC indicates that support for the project was high (> 70%) but knowledge about the restoration was low (< 60%), although public meetings were held prior to the release of bears to the area. This data indicates that restoration of the Louisiana black bear to the RRC is feasible and should be continued in an effort to establish a new breeding sub-population of bears in the region.

Submerged aquatic vegetation (SAV) plays an important role in aquatic systems, providing shelter, breeding habitat, and epiphytic forage for numerous fishes and aquatic macroinvertebrates. Since 1960, many lentic habitats in the southern U.S. have been invaded by Hydrilla verticillata, and in the last two decades this aggressive macrophyte has become the dominant species of SAV in the Atchafalaya River Basin in south central Louisiana. Because of its highly branched morphology and characteristically high densities, I found it difficult to quantitatively sample the macrofauna inhabiting hydrilla stands with traditional gears such as sweep nets, particularly under the canopy. As a consequence, I developed a suitcase trap that provided an efficient, quantitative method of sampling hydrilla-associated macroinvertebrates, and compared the abundance and taxonomic composition of samples collected with suitcase and sweep net samplers in dense hydrilla habitat. The suitcase trap is easy to deploy and retrieve, effective in all plant densities, permits estimation of macroinvertebrate densities by plant volume or dry weight, and is more effective than traditional sweep nets in describing the vertical distribution of macroinvertebrates inhabiting hydrilla-dominated littoral habitats. To provide a better understanding of the effects of exotic macrophyte invasions on the ecology of epiphytic invertebrates, and to identify possible management alternatives to mitigate detrimental impacts associated with these invasions on littoral habitat quality, I measured the density of vegetation-dwelling macroinvertebrates on exotic Hydrilla verticillata and native Ceratophyllum demersum in the Atchafalaya Basin. I collected a total of 34,996 macroinvertebrates from hydrilla and coontail habitat from May to August 2001 to determine how exotic hydrilla compares to native macrophytes in terms of macroinvertebrate habitat. Abundant macroinvertebrate taxa included Amphipoda, Decapoda, Diptera, Gastropoda, and Ephemeroptera. Overall, macroinvertebrate abundance between hydrilla and coontail was relatively similar. It is apparent from this study that, at least at the assemblage level, differences between abundance and distribution patterns of macroinvertebrates in different macrophyte species do exist. Principal component analysis displayed differences between macroinvertebrate assemblages, although the relative effects (and interactions) of declining or fluctuating water quality, macrophyte architecture, food resource quantity and quality, and predatory mortality on macroinvertebrate community composition remain to be identified.

<p class=MsoNormal style='text-indent:.5in;line-height:200%'>Terraces are a widely used wetland restoration tools in coastal Louisiana, yet the benefits of terraces are poorly documented.<span style='mso-spacerun:yes'> </span>Like terraces, coconut mats also may increase abundance of submerged aquatic vegetation (SAV), but their benefits are undocumented.<span style='mso-spacerun:yes'> </span>I compared SAV and seed abundance in a marsh pond among three treatments: terrace, coconut mat, and marsh.<span style='mso-spacerun:yes'> </span></p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>I evaluated terraces constructed in 1999 and coconut mats installed in 2001 in portions of unit 7 of Sabine National Wildlife Refuge that converted from emergent marsh to open water between 1956 and 1978. I randomly selected 3 terrace, marsh, and coconut mat stations. I evaluated transects 0 meters, 5 meters, and 50 meters (here after open water) from emergent vegetation at each station.<span style='mso-spacerun:yes'> </span>Submerged aquatic vegetation was evaluated on the terrace and marsh by harvesting SAV from 10-cm diameter cores, harvesting SAV from 1-m² plots, and raking: only 1-m² plot sampling was conducted on coconut mat treatments. I evaluated seed abundance on terrace and marsh transects with 10-cm diameter cores, which could not be used on the coconut mats.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>Submerged aquatic vegetation biomass differed between treatments and sampling dates. Biomass of SAV, as estimated by the cores, was greater on the marsh transects than the terrace transects. The SAV biomass, as estimated by 1-m² plots, was greatest during September 2002. Biomass of SAV, as estimated by 1-m² plots, was greater on coconut mats than terrace or marsh transects. Raking indicated that in September 2002, the percent occurrence of SAV was greater on the marsh transects than on the terrace transects.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>Seed biomass was greater adjacent to marsh than to terraces, which was similar to that in open water. Seeds of sawgrass (<i style='mso-bidi-font-style:normal'>Cladium jamaicense </i>Crantz) accounted for 87% of the seed biomass but did not germinate in a greenhouse.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>My results indicated that terraces failed to increase SAV abundance above levels found in open water as was predicted. I concluded that restoration planners should no longer assume that terraces increase SAV abundance. Coconut mats increased SAV abundance. Additional studies on a variety of areas and configurations are needed to determine if my observations are typical.</p>

Direct-contact (DC) and non-contact (NC) ultrasonic transmission (UT) methods were developed to characterize the structural performance of oriented strandboard (OSB). The UT variable velocity was shown to be sensitive to the physical impediments caused by flake interfacial boundaries and embedded voids. Both attenuation and root mean square (RMS) voltage were good indicators of the zero void densification level for OSB, a point of the greatest transmissivity of the stress wave energy. For both DC and NC methods, the predicted densities of the model were validated for spatial distribution over each OSB type. Based on the EN300 standard for panel manufacturing, the control limits were ±10% of the panel average density. The density prediction was found to improve with higher resin content (RC) and higher nominal density (ND) levels. From the out-of-limits plots, the predicted in-situ densities produced a reasonably spatial coherence to the measured values. All panels made with ND 0.60 g/cm3 or greater conformed well within the limits, with declining conformity towards lower RC panels. For each composite type made of different particle sizes, the equilibrium moisture content showed a decreasing trend toward smaller particle panels. The attenuation and RMS were good indicators for moisture change and densification level for each composite type. The velocity, sensitive to physical resistance of particle sizes, increased with increasing IB strength and sample density, manifesting the positive influence of layering, resin content, and the negative effect of bark as a constituent. The results of the creep rupture tests on commercial OSB using an acoustic emission (AE) technique indicated that the cumulative AE event count parameter was highly correlated with deflection parameter and appropriately represented the accumulation of incipient damage. Under high stress levels, specimens with high moisture content (MC) sustained the worse damages having the shortest creep rupture time followed by specimens with dynamically rising MC. Defects on the compression-side of the bending specimen were found critical to creep rupture than those on the tension-side. The in-plane fracture patterns tended to follow the defect trenches of low-density valleys, and worsened with greater variability of the horizontal density, indicating the need to measure and control the horizontal density variation within reasonable limits.

Decline of northern bobwhite (Colinus virginianus) populations during the past 30 years in southern portions of their range has increased efforts to improve habitat quality by integration of wildlife and forest management. Prescribed burns and herbicides have potential to benefit bobwhites, vegetation, invertebrates, and small mammal communities in pine-dominated systems. This study was conducted at 700-hectare Louisiana State University Idlewild Research Station of LSU's Agricultural Center in East Feliciana Parish. The experiment was conducted on 3, 10.12-hectare, 75 to 85 year-old, over-mature, uneven-aged pine stands on hilltops and sloping terrain. Experimental design included vegetation, invertebrate, and small mammal response to 3 treatments of 2 types of selective herbicide (imazapyr, imazapyr + glyphosate) and a control applied after an initial prescribed burn. Each stand served as whole plots and treatments as subplots within a split-plot arrangement. Treatments were randomly assigned and replicated across 3 stands. Herbicide treatments were more effective at improving vegetational structure for brood-rearing and nesting bobwhites. Plant and invertebrate species diversity declined on herbicide treatments during the first year, but increased on imazapyr plots during the second year. Bobwhite food plants increased on imazapyr plots for the first year and were greater on both herbicide treatments the second year. Herbicides reduced sweetgum but neither negatively affected hard mast producing species > 10 cm dbh. High overstory canopy closure and drought conditions may have negatively affected vegetation response. Herbicides did not produce bare ground percentages preferred by bobwhites. Prescribed burn alone created and maintained escape cover more suitable for bobwhites. Overall, imazapyr provided greater benefits to bobwhite, retained floristic species diversity, and greatly improved invertebrate diversity. Small mammal abundance increased on herbicide treatments presumably because of changes in vegetational characteristics and communities, and increased plant and invertebrate diversity on imazapyr treatments. Additionally, Peromyscus species was most common mammal trapped on all plots. Future research should evaluate vegetative response to herbicides under variable canopy conditions and different imazapyr application rates. We recommend managers target areas where prescribed burns are not possible and apply imazapyr strategically to create diverse, patchy habitat.

This study aims to contribute to addressing the gap that exists in determining the role an organizations internal operations play in information technology (IT) adoption in organizations. In particular, this research stems from investigating the relationship between company success at adopting information technology systems (the Internet) in the United States forest products industry (specifically, the lumber sector) and the extent to which organizational orientation within the industry supports the development. Following an extensive literature review, a conceptual model that represents the synthesis of information technology adoption-marketing orientation influences is developed. (This study does not infer that a company can acquire only one orientation at any one time). The United States forest products industry has traditionally been perceived as being production-oriented by many researchers. Marketing orientation, however, is a relatively new phenomenon that is gradually seeping into the way the industry does business as a result of competition, technology advancement, and the changing needs of consumers. Consequently, a number of propositions are tested and managerial and research recommendations are put forward. Overall, this research finds that email and the World Wide Web are the two most popular internet-based applications used by companies in the lumber industry. A positive relationship exists between factors of Internet adoption (extent of Internet application, user participation, perceived ease of use by user, perceived usefulness by user, and adoption diffusion by company) and perceived company effectiveness of Internet adoption under high and low marketing orientation, with a higher rate of increase in high marketing orientation than low marketing orientation.