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.

Studies in upland forests of the northeastern and upper mid-western U.S. indicate that high densities of white-tailed deer can reduce vegetation abundance, survival, and richness through over-browsing. In the southern U.S., few studies have examined the effects of deer herbivory on vegetation, and even fewer have done so in forested wetlands. At Jean Lafitte National Park's Barataria Preserve in south Louisiana, managers were concerned that white-tailed deer were concentrating and limiting forest regeneration near a walking trail, where hunting is not allowed. An exclosure study was started there in December 2002 and was conducted through July 2004 to quantify the effects of white-tailed deer on forest regeneration. Differences in densities and heights of naturally occurring tree and woody shrub species > 15 cm but < 200 cm in height were compared between six pairs of fenced and unfenced plots under the forest canopy. Fraxinus pennsylvanica and Quercus nigra juveniles also were planted in these plots, and survival and growth were compared between treatments. Naturally occurring shrub and juvenile tree abundance was compared among plots in treefall gaps and the paired plots under the forest canopy. White-tailed deer decreased the survival of planted Fraxinus pennsylvanica juveniles, but did not affect planted Quercus nigra juveniles or naturally occurring shrubs and juvenile trees. Juvenile trees were ten times more dense in treefall gaps than under the canopy because of the dominance of the exotic Triadica sebifera in gaps. Gap disturbances may be reducing diversity in these coastal wetland forests, rather than promoting diversity as they do in other forests. A more complete understanding of how deer modify the landscape may require future exclosure studies in treefall gaps.

Bottomland hardwood forests and associated fauna, including frogs, are disappearing. The 1990 Farm Bill created a wetland restoration program on private lands called the Wetland Reserve Program (WRP) that has the potential to reverse the declines in species associated with bottomland hardwood forests. As of September 2005, nearly 85,000 ha had been enrolled in Louisiana, but the structure and value of these wetlands to frogs is not known. I evaluated 22 restored and 8 reference wetlands from January through May in 2004 and 2005 to determine the effects of local and landscape scale habitat characteristics on frog species richness and occurrence. I used chorus count surveys, egg mass searches, and dipnet surveys to detect frog species each season. Vegetation characteristics at each wetland were determined seasonally. I evaluated landscape influences by using aerial photography and satellite imagery of the sites to determine the surrounding land use. I used multiple linear and logistic regression analysis and t-tests to evaluate the effects of local and landscape variables on species richness and individual species occurrence. I detected 12 of the 13 species expected to occur. Frog species richness did not differ between restored and natural wetlands, but species richness was higher in 2004 than 2005 (P < 0.0001), presumably due to much greater amounts of rainfall in 2004. Species richness in 2004 was positively influenced by median water depth and canopy cover (P = 0.0011). In 2005, permanent flooding, median water depth, emergent and floating vegetation, and canopy cover positively influenced species richness (P < 0.0001). Species richness also increased with forest in the surrounding landscape. Bullfrogs and bronze frogs were associated with canopy closure, herbaceous vegetation, and nearby forest. Northern cricket frogs were associated with shallow wetlands with floating vegetation, litter, and nearby forest. Gray tree frogs were found in wetlands with canopy cover, low emergent vegetation, and nearby agriculture. Restored wetlands in this study provided suitable frog habitat and supported similar frog species comparable to reference wetlands; however, additional frog and vegetation monitoring should be continued to evaluate restored sites throughout maturation.