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The golden-winged warbler (Vermivora chrysoptera) is an early successional Nearctic-Neotropical migrant songbird undergoing population declines range-wide. The Cumberland Mountains contain one of the southernmost populations where goldenwingeds occur in relatively high densities on old reclaimed surface mines. The three objectives of this research were to (1) describe the basic demography and habitat use of this population, (2) compare the demography of the Cumberland population to a population in Ontario, and (3) to model alternative land use scenarios and the impacts on both the golden-winged warbler and the cerulean warbler (Dendroica cerulean), another declining Nearctic-Neotropical migrant that occupies mature forests. Specifically, I modeled daily nest survival rate as a function of biologically meaningful covariates (Part 2) and the relative effects of habitat and demographic factors on territory size variation (Part 3) for the Tennessee population. There was some evidence of annual variation in nest survival rates and a decline throughout the nesting season, but I found little evidence that local habitat characteristics measurably affected nest survival. Territory size varied with the percent cover of vines and the number of snags. The single demographic factor related to territory size was nest success; birds with larger territories had a greater rate of nest success. I compared annual adult survival, fecundity, rate of population growth (λ), and mean time to extinction for Tennessee and Ontario populations (Part 4). Adult survival and fecundity were similar for the two populations such that predictions based on the theory of life history variation with latitude were not supported. Lambda estimates suggested that both populations were declining and I projected extirpation within 20-30 years without immigration. To further explore avian populations in the Cumberlands, I modeled coal mining, reclamation, and timber harvesting under a base-case scenario (as described by landowners and industries) as well as for alternatives that limited the amount of disturbance (Part 5). None of the scenarios were sustainable alternatives for cerulean and golden-winged warbler populations. My results suggest that future disturbances should be significantly limited to meet cerulean population goals and existing early successional habitat should be maintained and enhanced to sustain goldenwinged warbler populations.

The Little River in Blount County is home to one of the richest darter faunas in East Tennessee. Increases in agriculture and development on several tributaries and the main stem of the Little River are suspected as causes for reduced abundance in fish populations. Earlier research on the Little River identified three species, Etheostoma cinereum (ashy darter), Percina burtoni (blotchside logperch), and P. williamsi (sickle darter), as having low densities. From May – October 2009, snorkel observations were made at 16 predetermined sites along the mainstem of the river to determine abundance and habitat association of these target species, as well as abundance of P. aurantiaca (tangerine darter) for comparison with historic surveys. All fish observed while snorkeling were identified and microhabitat measurements were taken at the location of all target species. Observations included 39 fish species, including 273 P. aurantiaca, 58 P. burtoni, and 7 P. williamsi. Etheostoma cinereum were not encountered during this study. Our observations documented that darter populations during 2009 were significantly different than historic populations, indicating that local populations of the target species have been negatively impacted since the historic survey. E. cinereum has been consistently difficult to collect on the Little River, and previous sampling efforts have observed this species with less frequency in the last 30 years. The absence of this species in this study may be an artifact of habitat degradation due to development and agriculture, two consecutive years of drought in 2007-2008, or potential sampling bias due to high flows in 2009. Habitat measurements documented that P. burtoni were frequently associated with gravel and cobble substrates. This habitat association is indicative of the feeding habits of P. burtoni who use their padded snout to flip small stones and feed on the aquatic insects found underneath. Turbidity was closely associated with river mile, with a consistent increase in turbidity at downstream sites in the watershed.

I monitored 60 radio-collared and tagged pen-raised white-tailed deer (Odocoileus virginianus) to ascertain mortality rates on three areas in Louisiana from April 2001 - April 2002. Two of 60 were not used in the analysis because mortality occurred from complications with darting and an affixed radio-collar. Study deer were exposed to legal hunting mortality only if they emigrated from the three study areas. Twenty deer were released to the wild on the Louisiana State University Deer Study Area (LSUDSA) (4,810 ha), where 9 of 20 (45%) suffered mortality. Harvest accounted for 56%, vehicles 22%, and other 22% of the mortality on the LSUDSA. Two groups of 20 were released into 2 high fence enclosures, (275 ha and 608 ha), where 4 of 20 (20%) and 1 of 18 (6%) suffered mortality, respectively. Other mortality accounted for 100% of the losses in the high fence enclosures. Mortality rates were significantly lower in penned deer than in the released deer (Chi-Square 8.33 2df, P<0.05). These results suggest that high fence enclosures reduce emigration and hence deaths caused by hunting and vehicles and may reduce overall mortality. These results also suggest that a higher harvestable surplus may result from high fencing.

Benthic intertidal bivalves play an essential role in estuarine ecosystems by contributing to habitat provision, water filtration, and promoting productivity. As such, ecosystem level changes that impact population distributions and persistence of local bivalve populations may have large ecosystem level consequences, making it important to better understand the population distribution and ecology of native bivalve populations. Gametogenesis, recruitment, growth, mortality, size structure and density of the ribbed mussel, Geukensia demissa, were examined across a salinity gradient in southeastern Louisiana. In summer 2012, 100-m transects were placed at interior and edge marsh plots to collect data on mussel density, and vegetation data at duplicate sites in upper (salinity ~4), central (salinity ~8) and lower (salinity ~15) Barataria Bay, LA. Caged growth and recruitment plots were established adjacent to each transect, in April, and growth, mortality and recruitment of individually marked mussels within plots were recorded in November 2012. Mussels were randomly sampled monthly from low (~ 5) and high (~25) salinity marsh sites, and histologically processed to determine the seasonal progression of gametogenesis. Mussel densities were greatest within mesohaline marsh (66.6 + 18 m-2), J. roemerianus vegetation (191.2 + 42.7 m-2) and plots experiencing 20-60% annual flooding rates (46.7 + 13.8 m-2). Mussel recruitment, growth, size and survival were significantly higher at mid and high salinity marsh edge sites as compared to all interior and low salinity sites. Peak gametogenic ripeness occurred between April and September, positively correlated with temperature, and coincidental with seasonal shifts in salinity. The observed patterns of density, growth and mortality in Barataria Bay may reflect detrital food resource availability due to local site flooding rates, vegetation community distribution along the salinity gradient, and reduced predation at higher salinity edge sites.

The Atchafalaya River Basin (ARB), Louisiana supports a diverse centrarchid assemblage, characterized by abundant populations of largemouth bass Micropterus salmoides, black crappie Pomoxis nigromaculatus, warmouth Lepomis gulosus, bluegill Lepomis macrochirus, redspotted sunfish Lepomis miniatus, longear sunfish Lepomis megalotis and redear sunfish Lepomis microlophus. This dynamic floodplain ecosystem is comprised of a mosaic of macrohabitats, including natural bayous, shallow lakes, dead-end and open pipeline canals. I conducted an extensive feeding ecology study to determine the influence of these macrohabitats on foraging activity through stomach content and stable isotope analyses. I collected 2,036 centrarchids with electrofishing efforts in the summers of 2011 and 2012. Canonical correspondence analysis of prey items revealed evidence of resource partitioning within the assemblage, as suggested by limited dietary overlap and significant separation of diets among the seven species (F = 8.6516, P = 0.01). Multivariate analysis of stable nitrogen (δ15N) isotopes revealed evidence of trophic specialization (F = 24.29, P = 0.0001) within the assemblage, despite moderate overlap in foraging habitat suggested by carbon (δ13C) signatures (F = 2.76, P = 0.0147). Results of the generalized linear mixed model (F = 1.06, P = 0.3907) and multivariate analyses of stable isotopes (P = 0.86) indicated that macrohabitat did not have an overall effect on diets or isotope values. Traditional dietary indices, such as index of relative importance values, indicated specialization in prey preference for each species, suggesting a limited degree of competition between centrarchids. In summary, despite physicochemical differences among macrohabitats, these results suggest that prey selection was species specific and independent of macrohabitat type.Condition (relative weight) was also investigated to discern the potential influence of macrohabitat and physicochemical properties. Associations were species specific, indicating disparate manners of habitat utilization that may influence niche separation, although parameters such as dissolved oxygen differential were positively associated with multiple species. Although water quality and physical habitat characteristics differed among macrohabitats, trends in centrarchid condition suggest that while habitats within the ecosystem differ regarding their overall suitability as sunfish foraging habitat, all of the centrarchid species are generally able to flourish within the permanent waterbodies of the ARB floodplain.

Nest success of upland nesting ducks is the primary driver of duck population growth in the Prairie Pothole Region. Nest success is greatly influenced by nest predation and the amount of available nesting cover on the landscape. The decline in acres enrolled in the Conservation Reserve Program (CRP) in this region has negatively impacted the amount of available nesting cover, making nesting cover sparse and confined to small patches where predation rates are potentially elevated. I evaluated the efficacy of seasonal predator reduction on increasing nest success on low-grassland density (>10% grassland cover), 93 km2 landscapes in two different habitat types used by nesting birds, large fields and roadside ditches. Ditches were sampled because they are a major cover source in low-grassland density landscapes. I monitored 1,899 nests during the 2010-2012 breeding seasons. Predator reduction had a significant influence in large fields as nest success was 1.6 times greater in large fields on trapped sites (44% nest success) than on control sites (27% nest success). Predator reduction, however, did not significantly increase nest success in roadside ditches (13% nest success on trapped sites, 12% nest success on control sites). A large majority of monitored nests were located in large fields resulting in the overall effect of predator reduction significantly increasing nest success by 13%. These results indicate that predator reduction is an effective intensive management technique in low-grassland density landscapes and can be used as a management tool in a post-CRP era. Future research should evaluate different trapping techniques in efforts to increase nest success in the roadside ditches.

This project examined the ecologically and economically valuable eastern oyster (Crassotrea virginica) in Louisiana with two field experiments. Little information has been gathered on the performance of local Louisiana oyster stocks and no study has focused on a comparison of stocks among variable estuarine conditions. Additionally, the use of alternative grow-out methods and intensive cage aquaculture has never been evaluated in Louisiana. For the first study, a dermo-resistant stock of oysters (LSU-OYS: OBOY) was compared to three wild oyster stocks along a salinity gradient. The objectives of this study were to determine the optimal oyster stock(s) and the ideal grow-out condition(s) for intensive oyster aquaculture production. The second experiment compared the efficiencies of three commercially used, off-bottom culture systems. The objective of this study was to suggest which off-bottom grow-out method(s) is most suitable for use in Louisiana estuaries. The results of the stock comparison suggested that the selected dermo-resistant stock had greater mortality than two of the three wild stocks in all the environmental conditions tested. Specifically, wild stocks taken from low salinity areas had greater performance in test areas with low salinities while wild stocks collected from high salinity areas had greater performance at high salinity sites. The results of the grow-out method comparison revealed that an adjustable long line system (ALS) was the most suitable culture system in both high and low salinity conditions, specifically due to overall higher survival, improved growth in shell height, and reduced effort in labor and handling time. For the first time, the performance of four oyster stocks and three intensive oyster culture methods were quantified, suggesting superior stocks, grow-out conditions, and culture systems for augmenting wild production and increasing total production in the Louisiana oyster industry.

Agriculture and moist-soil management are important management techniques used on wildlife refuges to provide adequate energy for migrant and wintering waterbirds. However, in arid systems, the presence and accumulation of soluble salts throughout the soil profile can limit total biomass production of wetland plants and agronomic crops and thus jeopardize meeting waterbird energy needs. It is unknown how moist-soil management and traditional agriculture practices influence the accumulation and distribution of soluble salts of soil profiles. In this study of an arid wetland ecosystem, I determine: 1) the effect of long-term, distinct surface hydrologic regimes associated with moist-soil management and agricultural production on salt accumulation; and 2) the specific effects of rototillage and irrigation frequency on salinity concentrations and plant biomass in moist-soil impoundments. My study was conducted at Bosque del Apache National Wildlife Refuge near San Antonio, New Mexico. In May 2012, prior to the growing season, I collected one meter deep soil cores from both moist-soil impoundments and agricultural fields; cores were analyzed in 10 cm segments for soluble salt concentrations. I implemented a split-plot experiment to evaluate salinity concentrations in moist-soil impoundments between rototilled and no-till soils under a 9 and 14 day irrigation frequency. Soil salinity was measured in May and August of 2011 and 2012 and plant biomass in August. My findings suggest that agricultural fields contain significantly higher concentrations of soluble salts in deeper portions of the profile. This may be attributed to the lack of leaching afforded by summer agricultural irrigations as little connectivity to the groundwater and groundwater salinity was detected during groundwater monitoring. In contrast, periodic flooding in winter and summer flood irrigations in moist-soil impoundments may serve as leaching events and created a more dynamic groundwater hydrograph. This seasonal wetland hydroperiod may facilitate lower soil profile salinities but further research is needed to evaluate its successful use in agriculture fields to lower soil salinities. Few differences in soil salinity were detected between tillage and irrigation treatments within moist-soil impoundments. However plant above ground biomass of annual wetland grasses was greater in rototilled soils. This is most likely attributed to the effects of physical disturbance that stimulates germination rather than differences in soil salinity, however greater aboveground biomass does not necessarily equate to higher seed or tuber production.