This dissertation addressed comparative studies of sperm cryopreservation of diploid and tetraploid Pacific oysters, Crassostrea gigas, with an emphasis on the development of standardized and optimized protocols. This includes comparative ultrastructural differences between sperm from diploid and tetraploid oysters, methods for the rapid estimation of sperm concentration, optimization of cryopreservation, and evaluation of the mechanisms for sperm agglutination (formation of clumps or elongated "noodles") in thawed samples. Currently, cryopreserved sperm has not been commercialized in any aquatic species, and standardization and optimization could greatly benefit the potential commercialization of its use. In oysters specifically, cryopreserved sperm from tetraploids would facilitate the production of all-triploid seedstocks. In this study, sperm from tetraploid oysters were 25% larger in linear dimensions (lengths and widths), and 53% had 5 mitochondria compared to 4 in diploids. Spectrophotometric methods for rapid estimation of sperm concentration were developed and validated. The effects of cooling rate, single or combined cryoprotectants at various concentrations, equilibration time (exposure to cryoprotectant), straw size, and cooling method were evaluated for protocol optimization. Combination of the cryoprotectants polyethylene glycol (PEG; formula weight of 200) and methanol (for sperm from diploids) or PEG and propylene glycol (for sperm from tetraploids) were effective in retaining post-thaw motility only when PEG was at low concentrations (2-6%). Such effectiveness was especially manifested with sperm from tetraploids, for example, post-thaw motility as high as 50% was obtained with combined cryoprotectant. Sperm of tetraploid Pacific oysters were more susceptible to damage from cryopreservation procedures than were those of diploids, and male-to-male variation was significant for sperm from diploid and tetraploid oysters. Sperm agglutination was mainly due to the lack of sufficient cryoprotectant for specific sperm concentrations. These findings demonstrated the importance of standardization in sperm concentration and other procedures during cryopreservation. In addition, the systematic optimization of cryopreservation protocols involving interactions of multiple factors, recognition of male-to-male variation, and development of assays for sperm tolerance prior to freezing are all approaches important for the future potential commercialization of cryopreserved sperm in Pacific oysters and for other aquatic species as well.

Coastal forests in Louisiana are in decline due to natural and human caused changes in the hydrology of the region. Baldcypress and water tupelo trees have been further stressed by caterpillar herbivory in recent decades. Regeneration of water tupelo is crucial for cavity creation for nesting habitat for secondary cavity nesting bird populations. Insectivorous birds have been shown to decrease insect-caused leaf damage on trees in other ecosystems. Two experiments examining effects of insectivorous birds on tree growth were conducted in degraded areas of the Maurepas Swamp in southeastern Louisiana. In the first experiment, nest boxes were added to study plots in degraded swamp in an attempt to increase densities of secondary cavity nesting birds, and to determine if increased insectivorous bird abundance resulted in improved shoot growth of baldcypress saplings. Prothonotary Warblers were the only bird species to utilize nest boxes, nest boxes did not significantly increase densities of Prothonotary Warblers, and insectivorous bird abundance was not correlated with baldcypress shoot growth. In the second experiment, bird exclosures were erected around planted baldcypress and water tupelo seedlings. Leaf damage on trees within bird exclosures and those with an insecticide treatment was not significantly different from controls. Foraging observations of Prothonotary Warblers and Northern Parulas, and video nest monitoring of Prothonotary Warbler nests during caterpillar activity, suggest that birds demonstrate a functional response to baldcypress leafroller caterpillars. Results of video nest monitoring suggested that successful Prothonotary Warbler nests active during baldcypress leafroller activity have the potential to protect 76 grams dry weight of baldcypress foliage. However, birds only foraged on baldcypress taller than 2m, and forest tent caterpillars were only observed to be consumed during the first and final caterpillar instar stages. Planted baldcypress seedlings grew faster than planted water tupelo, and water tupelo seedlings had zero height growth, or died-back four times as frequently as baldcypress. Insectivorous birds provide baldcypress some protection from caterpillar herbivory, but birds may offer little protection to water tupelo, especially trees less than 2m tall.

Understanding habitat affinities of wintering grassland birds is pertinent to their conservation. The objectives of this study were to evaluate the 1) effect burn history has on vegetation structure in coastal prairie; 2) habitat associations of the most common avian species; and, 3) home range size and site fidelity of Le Conte's Sparrow (LCSP). Data were collected on sites with 1-, 2- and 3-year burn histories during the winter of 2002 at Brazoria National Wildlife Refuge, Texas. Line transects were conducted to estimate bird abundance and vegetation measurements were recorded for herbaceous density, shrub density, and community type. Twenty-six Le Conte's Sparrows (Ammodramus lecontii) (LCSP) were radio-marked, in 1- and 2-year burn units, and located for approximately 10 days. One hectare plots on each burn unit were flush-netted once each month. Burn history was highly correlated with herbaceous vegetation and shrub density. LCSP were most common in areas of medium herbaceous density, low to medium litter densities, and areas with tall vegetation. LCSP also occurred in areas with low shrub densities, but abundance was significantly higher in areas with dwarf wax myrtle (Morella cerifera). Savannah Sparrows (Passerculus sandwichensis) were most often found in areas with low herbaceous and shrub densities. Sedge Wrens (Cistothorus platensis) (SEWR) were most common in areas with dense herbaceous vegetation, but showed no relationship to shrub density. SEWR were associated with areas where saltbush and tallow were present. Swamp Sparrows (Melospiza georgiana) were most common in areas of high shrub densities, but demonstrated no relationship to herbaceous vegetation densities. LCSP were sedentary during winter with a mean home range of 2.41 ha (72% < 1 ha) with a 50% probability, and 10.31 ha (44% < 1 ha and 55% < 1.5 ha) with a 95% probability. Home range size did not significantly differ between burn year (p = 0.227). LCSP appeared to exhibit a behavioral response to capture (p < 0.001) with estimated capture probability of 0.462 and recapture probability of 0.056. Maintaining a mosaic of prairie, in three year burn rotations, and controlling woody invasives will provide sufficient overwintering habitat for SAVS, LCSP and SEWR.

Hydrilla verticillata invaded south central Louisiana during the 1970s subsequently becoming the dominant submerged macrophyte in floodplain habitats of the Atchafalaya River Basin. The effects of hydrilla on littoral habitat structure, water quality, fish, and macroinvertebrates have been pervasive, and I hypothesized that dense hydrilla stands would also impact vertebrate predation on resident macroinvertebrates, although predation effects would likely be mediated by bed position. During 2003 and 2004, I conducted exclosure experiments in the Atchafalaya River Basin with artificial substrates to test for variations in hydrilla bed macroinvertebrate communities caused by predation, plant architecture, and bed position. To determine invertebrates consumed by fishes, I also examined stomach contents of potentially invertivorous fishes inhabiting these beds. Results indicate that position and predation are important in structuring macroinvertebrate communities, whereas plant architecture had little effect. My diet analyses indicate that the fishes sampled fall into three categories: 1) those that do not feed on macroinvertebrates; 2) those that feed on small invertebrates (e.g., dipterans); and 3) those that feed on large invertebrates (e.g., decapods) and poeciliid fishes. Further, the diets of the invertivorous fishes coincide with the distributions found in the macroinvertebrate community and, in general, those macroinvertebrates most commonly found in fish diets occurred in greater densities within the bed interior.

The unavailability of total economic values of indigenous people in Indonesia, both in the short and long term, has created the rejection of their existences in the forest area. The purpose of this study is to estimate the total economic value of sustainable forest management conducted by indigenous tribes in Indonesia using total economic value concepts. The tribes total economic value is expressed by estimating the use value, indirect use value and non-use value. The study used benefit transfer and survey methods using questionnaires to estimate the tribes total economic value. The estimated total economic value of the Benuaq Dayak of U.S. $ 6,025.88 per hectare per year was calculated by summing the direct use value (U.S. $0.028 per hectare per year), indirect use value (U.S. $3,156 per hectare per year), and non-use value (U.S. $2,870 per hectare per year). The research hypothesis that the Benuaq Dayaks sustainable resource management has economic value is supported. The research predicted that the estimated total economic value of the Benuaq Dayaks management might create a new perception of the tribe, the private companies, and the government.

In this study, the effect of notch length on impact strength and fracture toughness was examined to exploit the use of wood plastic composite (WPC) as structural materials. Impact and fracture toughness test methods and estimation procedures were carried out. To evaluate the impact strength of WPC, five different notch sizes with two different fiber orientations on the load head were prepared. In terms of fracture mechanics, notch length was converted to stress concentration factor and the relationship between stress concentration factor and impact strength was determined. Fracture surface of impact specimens was investigated to evaluate the fracture mechanism of WPC by scanning electron microscopy (SEM). For the determination of fracture toughness of WPC, a short bar specimen with a rectangular cross section and a different notch size was used. To obtain the stress intensity factor (K_I) for the mode I case, a finite element method (FEM) was carried out. The simulation of the stress intensity factor was performed on four successively refined meshes via quarter point elements around the crack tip. By means of an asymptotic analysis, the verification of the simulation was also presented. The experimental results showed that impact strength of WPC was highly dependant upon the fiber orientation and stress concentration factor. However, fracture toughness was independent of the change of the length of the notch. Fracture toughness of WPC was estimated to be 1.79 MPa√<font style="text-decoration: overline;">m</font> using a four point bending test. The results of the simulation showed that stress intensity factor of WPC was estimated to be 584.9 (kPa√<font style="text-decoration: overline;">m</font>). The results of normal stress at the crack tip from a common sequence of four successively refined meshes were diverged while the results of the stress intensity factors converged. The strength of singularity for normal stress (σ_x) was 4.92 which is quite close to that of true singularity (0.5) for the sharp crack tip when Θ=180°. Crack opening angle (COA) of the four point bending specimen was also estimated to be 50° on the basis of strength of singularity determined from finite element method.

Declines in annual oyster landings and problems associated with seasonal reduction of oyster meat yields have increased interest for development of techniques to produce oysters with enhanced growth characteristics. Research interest has been focused on developing improved lines by induction of polyploidy. The goal of the present study was to evaluate the enhancement of gonadal development of triploid oysters, by the use of the hormone estradiol 17-â (E2) to produce viable eggs for the development of tetraploid broodstocks. Previous studies with the Pacific oyster, Crassostrea gigas, have shown: (1) the need to use the larger eggs of triploid females to accommodate a tetraploid nucleus, and (2) that E2 appears to be responsible for ovarian maturation. The objective of this research was to compare the effect of three dosages of E2 (0.0, 37.5, 75.0 ng/g wet weight) on ovarian maturation of diploid and triploid eastern oysters, Crassostrea virginica, by measuring: 1) gonad-to-body ratio; 2) oocyte area; 3) levels of E2 in the hemolymph; and, 4) by qualitatively staging gonadal development. Experiments were performed in August of 2003 and May and August of 2004 for 9, 12, and 15 days. Image analysis of histological sections (gonadal condition) and enzyme immunoassays (E2 levels) were used to evaluate the effects of steroidal treatments. There was no evidence of oysters in spawning condition in any of the control groups of the triploid oysters, yet oysters in spawning condition were found in the low and high dose treatments in percentages as high as 40%. For the diploid oysters, the effect of E2 was less apparent due to their natural state of fecundity during the summer months. Concentrations of E2 were measured in diploid and triploid oysters and their levels fluctuated from 13.8 to 29.1 for diploids and from 16 to 33.8 for diploids, with respect to the stage of gonadal maturation. The overall response of triploid oysters to E2 suggested that this hormone had a positive effect on ovarian maturation. These results can have direct applicability for the development of tetraploid broodstocks in the eastern oyster.

In 1994, a 17 yr old, slash pine spacing study was thinned to 35% of the maximum stand density to evaluate the influence of prethinning stand conditions on postthinning growth after thinning to a common stand density. It was expected that plots thinned to a common growing stock level should have equal growth increments and if growth was not equal then the difference was related to prethinning stand conditions. Stand growth variables of quadratic mean diameter increment, stand-level basal area increment, and gross-volume increment were evaluated to determine the influence of initial spacing, stand density, and prethinning crown size before thinning and for 5 years after thinning. Lower values of relative stand densities were associated with initially wider spacings before thinning and higher values 2-5 yr after thinning. Before thinning, quadratic mean diameter increment was positively related to initial spacing and prethinning crown dimensions and negatively related to relative stand density. After thinning, quadratic mean diameter increment was not significantly influenced by initial spacing, but it was inversely correlated with prethinning crown ratio 5 yr after thinning as relative stand density increased. Stand-basal area increment was negatively correlated with prethinning crown width, crown ratio, and crown volume before thinning, but it was not significantly related to initial spacing or relative stand density before or after thinning. Gross-volume increment was positively influenced by initial spacing and prethinning crown dimensions and negatively related to relative stand density prior to thinning. These positive relationships were observed during yr 2, 3, and 4 after thinning where wider initial spacings produced larger increments in volume as relative stand densities increased. Prethinning crown dimensions remained correlated with gross-volume increment after thinning. However, after thinning, these correlations with prethinning crown dimensions held a consistent relation with postthinning growth and also conformed to conventional growth-growing stock relationships as stands developed. The significant relationships detected between gross-volume increment and initial spacing, prethinning crown dimensions, and relative stand densities support that prethinning tree characteristics affected postthinning gross-volume increment for the duration of this study.

Decline of amphibians, reptiles, and numerous Neotropical migrant birds has been attributed to habitat destruction and alteration, which warrants examination of these groups in managed forests and their association with habitat characteristics at multiple spatial scales. We surveyed avifauna and herpetofauna communities in 3 managed forests in Louisiana during 2003-2004. Study areas included Sherburne Wildlife Management Area (WMA), a bottomland hardwood forest under uneven-aged management, Bens Creek WMA, an even-aged, short-rotation loblolly pine plantation, and Sandy Hollow WMA, a longleaf pine-savannah maintained with prescribed fire. Field techniques included surveys consisting of avian point counts, drift fence arrays (PFFT), cover boards, visual encounters, anuran calls (ACS), and microhabitat. We derived landscape variables with GIS landcover maps and ArcView GIS 3.3. General trends included the following: PFFT and ACS accounted for the greatest percentage of detections among herpetofauna surveys, and results primarily reflect these efforts. Anuran calling surveys made a substantial contribution to total number species of detected. Species of conservation concern were among detections of both early- and late-successional bird species. At Sherburne, abundance and richness of amphibians, and occurrence of late-successional birds were greater in uncut and individual-selection stands, whereas occurrence of early-successional birds was greater in recent selection cuttings with groups. Abundance of reptiles did not differ across stand type. At Bens Creek, abundance and richness of anurans was greater in 1-year and 11-23-year stands, whereas abundance and richness of lizards was similar across stand age. Late-successional bird species occurred with greater frequency in 11-23-year stands at Bens Creek, whereas frequency of occurrence of early-successional bird species was greater in 1-year and 4-5-year stands. At Sandy Hollow, abundance of reptiles was greater than amphibians, and occurrence of avifauna was similar to pine-savannah ecosystems elsewhere. Responses to habitat factors at all scales were species specific. In general, canopy closure and shrub cover were the most frequent predictors of occurrence at the microhabitat scale. At the landscape scale, canopy closure and streamside management zones were important predictors of occurrence at Bens Creek, whereas openings and shape complexity of longleaf pine and longleaf savannah were frequent predictors of occurrence at Sandy Hollow. Effects of selection cutting and stand age appear to benefit certain species, including species of conservation concern, but are potentially costly for other species. Efforts to combine management of timber with conservation of amphibians, reptiles, and songbirds must take into consideration both the complexity of habitat requirements of species within these groups and the landscape context in which these requirements occur.

Body size is highly variable among geese, both at intra- and interspecific levels. Interspecific variation in several behaviors has been attributed to differences in body size in geese: incubation constancy, tendency to maintain family units, and time spent foraging. Body size has important physiological implications for birds, mostly because mass-specific metabolic rate is greater for birds of smaller mass. The Body-size Hypothesis predicts that smaller species deplete their energy reserves at relatively faster rates than do larger species. Hypotheses and conclusions concerning effects of body size on waterfowl behavior often are based on comparisons of species that confront different climates, habitat types, and food resources, and migrate variable distances with different energetic costs. Accordingly, I controlled for such variation by comparing the behavior and physiology of lesser snow geese (hereafter snow geese) and Ross's geese, which are closely related and highly sympatric throughout the annual cycle. I found that incubation constancies of both species averaged 99%. The defeathered ventral area was positively related to clutch volume and inversely related to prolactin levels in female Ross's geese, but not in female snow geese; moreover, prolactin levels and body condition were inversely related in Ross's geese, but not in snow geese. I documented that 5 of 5 female snow geese and 1 of 5 female Ross's geese possessed fully-developed brood patches. In winter, I documented that Ross's geese spent more time feeding than did snow geese. All these findings, except that for incubation constancy, were consistent with predictions of the Body-size Hypothesis. Finally, I studied effects of intraspecific body size variation on goose behavior by studying movements and behavior of snow geese in southwest Louisiana. I found that both adult and juvenile snow geese from coastal marshes had larger bodies and bills than did those from rice-prairie habitats. Adult snow geese from coastal marshes spent more time feeding than did those in rice-prairies, whereas the opposite was true for juveniles. I conclude that snow geese in southwest Louisiana segregate into coastal marsh and rice-prairie habitats by body morphometrics, but move too frequently between the 2 habitats to be considered separate populations.