Coastal wetland forest ecosystems rely on the intimate interactions of hydrology, salinity, and coastal forest vegetation. The boundary between marsh and forest is often where hummock-swale terrain exists. It remains unknown as to the degree to which trees may experience varied salinity level within hummocks provided with freshwater flux. This study examined the hydrological regime of the hummock-swale terrain that resulted in salinity variation and whether freshwater source exists for baldcypress. Natural tracers of stable isotopes of water and salinity were applied to understand the sources of water. To better examine the tracers used, we conducted several experiments to gain a clearer understanding of the variability in isotopic compositions in throughfall and by extracting water from wood and soil. The studies indicated that baldcypress are able to avoid saline flooding from hummocks. We found that the throughfall process does correspond with the canopy structure enough to strongly influence throughfall amount but only weakly influence isotopic composition. Also at microtopographic scale, salinity of the groundwater in hummocks remained chronically high and vertical solute exchange was little. The shallow subsurface of hummocks was a zone characterized by slow dilution and episodic salinization rather than slow salinization and episodic flushing. Rainfall and frequent inundation by generally low-salinity water flushed salts and maintained lower salinity in upper layers. Thus the baldcypress forest overall occupies a nonsaline site, but the episodic influxes followed by slow leaching occurs superimposed on a layer of salinity that lies presumably beneath the root zone for most of the growing season. In addition, the systematic errors were little considering the isotopic fractionation during water extraction from wood.

The greatest diversity of crayfishes, especially of rare Orconectes species, is found in the central Louisiana watersheds (Red River, Mermentau, Calcasieu, and Vermillion-Teche), and most species are widely distributed among the drainages. The purpose of this research was to lay groundwork for species distribution and metacommunity modelling for crayfishes in this region. To address this goal, two field studies were performed in the summers of 2013 and 2014, as well as an indoor laboratory study. Analyses of broadly distributed species indicated no significant correlations between species abundances and habitat variables nor any significant environmental gradients for those species. Within-drainage variability of habitat was substantial in this study and a large range of site conditions were sampled within any particular drainage, despite significant drainage differences. Subsequent analysis of drainage-restricted species indicated that drainage-scale modelling is suitable for endemic species such as Procambarus pentastylus and P. natchitochae. However, more restricted Orconectes maletae, O. blacki, and O. hathawayi could not be effectively modelled at the drainage scale, in part because they were not detected in the majority of samples. Examination of gear types and times of day indicated that catch per unit effort (CPUE) and average total length of crayfish was greater with electrofishers than with dipnets; however, no differences between time of day were detected for either CPUE or crayfish total length. Differences in estimates of sample diversity using different combinations of gears and times of day were detected when calculated on a per individual basis, but not on a per site basis. In intraspecific competition trials, body size and chelae width were found to be significant biological factors in determining the odds of dominance in O. blacki and P. pentastylus. Presence of predator cue (water conditioned by Micropterus salmoides) generally reduced frequencies of dominance interactions in both species and generally increased median shelter occupancy times for both species. This research provides much needed information on the distributions and ecology of central Louisiana crayfishes, and future studies will be needed to quantify genetic units, dispersal corridors, and interspecific interactions between other co-occurring species and to characterize the central Louisiana crayfish metacommunity.

Wading birds in southwestern Louisiana and southeastern Texas rely heavily on rice fields and crawfish ponds as foraging areas; however, little information exists on food availability throughout the annual crop cycle. The objectives of this study are: 1) Develop a classification for rice and crawfish fields based upon tillage, forage crop (for crawfish fields), water depths, vegetation density, vegetation height, and other visible parameters; 2) Quantify the distribution of rice and crawfish fields in various stages across the landscape through time; 3) Determine the effects of rice and crawfish field types and landscape characteristics on wading bird use; and, 4) Evaluate the relationships among field classification, habitat characteristics, and invertebrate densities (including crawfish) in selected field types through time. To address these objectives, I used stratified-random sampling to select 50 1.6 km long road transects in 7 parishes and 3 counties of the major rice/crawfish producing parishes/counties in southwestern Louisiana and southeastern Texas. From April 2013 April 2014 I conducted monthly surveys along the transects to assess rice/crawfish habitat conditions, as well as conduct waterbird surveys. From May 2013 until February 2014 I conducted quarterly macroinvertebrate and nekton sampling of selected fields in the region. The results of the study demonstrate the intra-annual variability in resources available to waterbirds and other wetland dependent wildlife throughout the coastal prairie region. Rice agriculture as a percentage of surveyed land use varied from 0-30%. Crawfish agriculture varied in a 12-month period from 0-15% of lands surveyed. Crop type, irrigation and tillage were the factors that contributed most to macroinvertebrate abundance and biomass. Waterbird use of fields was not randomly distributed. Irrigation, seeding method and tillage all seemed to contribute to waterbird use of fields surveyed in the region.

The thesis examines a panel of trade flows during 2009-2013, exploring the influence of regulatory quality on the pattern of forest products imports by India from 143 partner countries. The study applies a pooled regression model followed by Generalized Least Squared (GLS) technique and a more robust Feasible Generalized Least Squared (FGLS) method of estimation with regulatory quality, distance between the partner country and India, total forest area of partner country, GDP and population indicators to assess the impact of partner countrys regulatory quality and other trade-related factors on imports of forest products by India. The results support the notion that imports of forest products depend on regulatory quality, the distance between the trading countries, forest cover, the size of the economy and other factors considered in the model. The study also considers the impact of regional variability on forest products import by India. Quantitatively, the results suggest that a 1 percent improvement in regulatory quality of the partner country would yield a 6.10 percent increase in imports of forest products by India. A 1 percent increase in distance between India and the trading country yields a 0.60 percent decrease in total import volume, whereas a 1 percent increase in forest area of partner country and a 1 percent increase in GDP of partner country yields an increase in forest products imports to India by 0.24 percent and 0.75 percent, respectively. Thus, it confirms that while improvement in regulatory quality of partner countries contribute to improved imports, improvements in the GDP of partner country and increase in the total forest area are equally important in facilitating the growth of forest products imports by India. This improvement implies policy emphasis on the governance, economy and environment of the trading countries and, are important to support the furtherance of the volume of trade flows across countries.

The Rusty Blackbird (Euphagus carolinus) has gained notoriety in recent years as one of the fastest declining North American bird species, with a global population loss of as much as 95%. Causes of the decline are not completely understood, but the high rate of forested wetland change in the southeastern United States suggests that wintering habitat degradation may be a primary driver. To better inform management on critical wintering grounds, I surveyed 68 sites in Louisiana where Rusty Blackbirds had been known to occur to address how occupancy changes with habitat type and colonization and extinction rates vary with ground cover, rainfall, and invertebrate biomass. Rusty Blackbirds use a large area while foraging on the wintering ground, therefore management may need to be targeted to even larger spatial scales. I assessed the relationship between statewide Rusty Blackbird abundance data from the Louisiana Winter Bird Atlas and landscape scale habitat within 512 unique USGS 7.5-minute quadrangles using datasets on land cover, cropland cover, and soil type. Results indicate that forested wetlands are important habitats associated with Rusty Blackbird presence, but only under certain conditions. Rusty Blackbirds prefer shallow water for foraging. At my sites, deep water cover increased with the cover of forested wetlands and may have deterred Rusty Blackbirds from using primarily forested wetland sites. The most important variables associated with transience were wet leaf litter and invertebrate biomass, which were both positively associated with colonization and negatively associated with extinction probability. For the Louisiana Winter Bird Atlas data, the top model included all explanatory variables for Rusty Blackbird abundance. Abundance increased with cover of soil hydrologic groups C, C/D, and D, which are capable of retaining surface water, suggesting that at larger scales water cover is more important than any particular habitat type. Pecans are an important food source for wintering Rusty Blackbirds and pecan orchards had the strongest positive relationship with abundance. In addition to maintaining pecan groves on the landscape, Rusty Blackbirds may benefit from management for shallowly flooded forested wetlands that can support high amounts of wet leaf litter on the grounds surface and abundant invertebrates.

The Atchafalaya River Delta system along with the Wax Lake Outlet Delta and the Mississippi River Delta are the only three areas in Louisiana where land is being gained. Beneficial use of dredge spoil from shipping channel maintenance is used on the Atchafalaya River Delta to supplement natural accretion. These dredge spoil islands have the ability to provide valuable nesting habitat for a variety of waterbirds, including Mottled Ducks. Previous studies on these islands reported mammalian predation to be a significant cause of nest failure for Mottled Ducks. I tested the hypothesis that predator reduction through trapping would increase Mottled Duck nesting success. I selected six islands based on vegetative conditions optimal for nesting vegetation and separated them into three trapped and three control islands. I found mammalian depredation of Mottled Duck nests to be rare and was not successful in detecting or trapping any predators. Instead, I found that flooding, which had been a minor issue in a previous study, to be the major cause of nest failure during the 2012 and 2013 nesting seasons. I found that Mottled Ducks strongly preferred nesting on islands that were isolated from the main delta complex. I used LIDAR elevation data as well as NOAA and pressure transducer data logger water level data to evaluate the relationship between nest elevation and nest success. I found no apparent relationship between nest elevation and nest success. Mayfield nest success for Mottled Duck nests was 20.5% in 2012 and 11.5% in 2013 with 34.5% of nests destroyed by flooding. Further research into the effects of flood duration, frequency, and incubation stage at flooding as well as considering partial loss of clutches may show a clearer relationship between nest success and the effects of flooding

Complex fluvial processes influence floodplains. River modifications in the 1930s have affected hydrogeomorphic processes influencing the lower White River in southeastern Arkansas. The overall objective of this study was to better understand the hydrologic and geomorphic influence on the floodplain forest. We used the HEC-RAS model to quantify hydrologic relationships within the floodplain before and after 1930s river modifications. The model can replicate flooding within 3-5 m. Despite river modifications, HEC-RAS modeling showed headwater floods influenced the upper reach of the floodplain while backwater floods from the Mississippi River influenced the lower reach of the floodplain. Post-1930s incision that occurred from the confluence to the middle reach of the lower floodplain reduced the flooding extent primarily in frequent (< 5-year return interval) headwater floods. In contrast, incision only reduced flooding extent in the smallest (1-year return interval) backwater floods, and larger backwater events were largely unaffected. Modeled flooding regimes for PNV classes were more distinguishable among floodplain reaches than among PNV classes. The upper reach in the floodplain flooded more often from headwater floods, but the lower reach in the floodplain flooded deeper by backwater floods. Post-1930s incision reduced flooding depth and flooding extent the most in the riverine backwater upper zone , riverine backwater lower zone, and riverine overbank natural levee classes. The largest reductions in flooding depth and extent within these classes occurred during the more frequent floods, which are most important for ecological processes

Avian diversity in degraded fragmented Amazonian landscapes depends on the persistence of species in cleared and disturbed areas. Regenerating forest facilitates bird dispersal within degraded Amazonian landscapes and may tip the balance in favor of persistence in previously depauperate habitat patches. Despite the potential value of Amazonian second growth, we lack comparisons of demography among second growth, continuous forest, forest fragments in regenerating landscapes, and truly isolated fragments. Here, we used point-count and capture data to compare Amazonian bird communities among continuous forest plots, 100 ha forest fragments with adjacent second growth, 100 ha forested islands bounded by water, young and older second growth plots. We also compared differences in survival, population growth and age ratios between primary and mature secondary forest. Among foraging guilds, understory insectivores and obligate-flocking species were nearly absent in islands and young second growth. Fragments surrounded by a regenerating matrix were surprisingly species rich, suggesting that a developing matrix may mitigate extinction associated with fragmentation. Survival and population growth was lower in mature second growth relative to primary forest for all foraging guilds except frugivores, gap specialists and ant-following birds. Similarly, age ratios were skewed towards more adult insectivorous birds in older forest; these findings suggest that dominant individuals may preferentially use older forest. Our findings reinforce that true islands are extinction-driven systems with distinct, depauperate communities. Islands are not appropriate comparisons to forest fragments in some landscapes. In contrast, succession of bird communities in second growth facilitates recolonization of forest fragments, permitting fragments as small as 100 ha to support bird communities similar to continuous forest.

Each year, floodplain habitats are inundated and dewatered throughout the lower Mississippi River during the flood pulse. Many organisms, particularly fishes, are facultative or obligate users of inundated floodplain habitats for foraging and reproduction. The abundance and distribution of these fishes are influenced by annual floods, ranging from weeks to months depending on intensity and duration of the pulse. One major consequence of anthropogenic alterations to the river has been the sequential loss of connectivity of floodplain habitats. In light of these changes, a concentrated effort has been made to restore the integrity of the LMR floodplain. An integral part of restoration efforts depends on understanding characteristics of aquatic habitats that promote reproduction, growth, and survival of floodplain species. In collaboration with USFWS and GCPOLCC, this project investigated fish-habitat relationships and identified aquatic habitat conditions that promote healthy alligator gar populations. My objectives for this study were to: 1) identify floodplain habitat features associated with desired fish assemblage characteristics based on the role of Alligator Gar as a surrogate species; and 2) develop a sampling protocol for surveying alligator gar with side-scan sonar. The sampling program involved collecting fishes with gill nets throughout the flood pulse and documenting species and sizes of fishes collected in relation to habitat characteristics. A total of 373 fishes representing 14 species were sampled across 62 sites during two pulse periods (2013-2014). The most frequently caught species was Smallmouth Buffalo, which made up approximately half of the total catch followed second by Bigmouth buffalo. Considering two species of conservation concern that were present, Paddlefish (n=8) were found strictly in OPWA and FLVG. Conversely, Alligator Gar (n=31), which were caught at 22 sites with 6 sites producing multiple fish. These sites also yielded significant abundances of other fish species, including Gizzard Shad (53.8%; n=13), Common Carp (45.5%; n=22), and Longnose Gar (60.0%; n=5). Analyses revealed that fish assemblage structure was strongly related to habitats in REWA and OPWA, distance to river, sample year, and river stage. Alligator gar were reliably detected with side-scan sonar, yielding 788 images collected and a total estimate of 515 gar with approximate total lengths > 1m. These data will assist in developing sound conservation strategies throughout the LMRV to identify areas that fit the USFWSs needs in prioritization of conservation and floodplain restoration projects and the Services initiative for strategic habitat conservation. A better understanding of this floodplain system and the characteristics that contribute to its habitat value will hopefully provide the basis for development of management programs to enhance floodplain fish diversity and accessibility of floodplain habitats to riverine species.

I surveyed random (mail and internet panel surveys) and convenience samples (web surveys) of Louisiana waterfowl hunters following the 2009-2010, 2011-2012, and 2012-2013 seasons. I hypothesized significant differences in effort, success, satisfaction and demographics, but no difference in attitudes, in responses between random and convenience survey methods. I mailed to stratified random samples of 2,500 in 2010, 6,400 in 2012, and 2,500 each for mail and on-line internet panel response in 2013. An identical web survey, hosted each year during the same time period, facilitated open-access response. I received 1,676 usable responses in 2010 (727 mail and 949 web), 2,382 usable responses in 2012 (1,096 mail and 1,286 web), and 2,121 usable responses in 2013 (590 mail, 145 internet panel, and 1,407 web). Cost per usable response averaged $39.10 for mail surveys, $41.70 for the internet panel survey, and $3.20 for web surveys. Compared with the mail surveys and internet panel, respondents to the web surveys hunted more frequently, harvested more waterfowl, and placed higher levels of self-identity or importance on waterfowl hunting. However, I noted similarities in attitudes toward regulatory alternatives across survey methods in all 3 studies. I tested the random and convenience samples using binary logistic regression of variables measuring effort, success, satisfaction, and demographics, exceeding statistical standards for classification accuracy in 2010 and 2012, but not 2013, resulting in a mixed conclusion for these characteristics. Identical tests of attitudinal variables failed to meet statistical standards for classification accuracy in all 3 studies, confirming the inability to distinguish respondents by survey method using attitudinal variables. Polar reclassification of attitudinal responses into bichotomous categories led to identical managerial conclusions in 12 of 13 Likert-scaled questions, irrespective of survey method. Results support my hypothesis of no significant differences in hunter attitudes between random and convenience samples. These findings identify an opportunity to increase stakeholder feedback at reduced costs using web-based surveys. I suggest that survey methodology be carefully linked to survey objectives, and that open web surveys may be used to supplement random surveys in investigations of stakeholder attitudes to inform development of natural resource policy.