This study examines wind generated waves during winter storms, their transformation/attenuation near the marsh edge, and the resulting saltmarsh edge erosion. A simple numerical model for wave generation, transmission and marsh edge erosion was developed and validated against observations from Lake Borgne, Louisiana. Results suggest that meteorological conditions modify the local water depth via wind or wave setup and atmospheric pressure, thus exerting a first order control on the location of wave attack, which in turn determines the type of wave forces (shear vs. impact) that dominate the erosion process. Scarp failure follows, at a location determined by water level, creating multiple erosive scarps and terraces. High measured erosion, likely due to marsh edge destabilization followed by subsequent frontal passage forces differential marsh erosion, exposing underlying substrate to further erosion. A conceptual model for marsh edge retreat is developed using these observations and supported further by model predictions.

To combat the rapid degradation of the Louisiana coast, the Louisiana Coastal Protection and Restoration Authority has planned strategic land building initiatives throughout the Louisiana Gulf coast, including beach nourishment and marsh creation projects. It is commonly agreed that the state lacks sufficient renewable sediment resources to maintain the planned CPRA land building program. However, Louisiana, the state that commonly ranks last in state recycling percentage, recycles an estimated 0.6% of the waste glass consumed in the state. Glass is predominantly silica sand. This thesis evaluates laboratory‑determined characteristics of recycled crushed glass cullet to assess its suitability as a renewable aggregate for beach nourishment and marsh creation projects. Specifically, the research herein evaluates geotechnical and settling characteristics of recycled crushed glass cullet produced in Pearl River, Louisiana. Additionally, this research evaluates the effects on beach nourishment and marsh creation design parameters of blending this material with Gulf coastal sediments.

The cycling of arsenic in the marine photosynthetic plants and algae was examined by analysing total arsenic concentrations and arsenic species in selected marine photosynthetic organisms from the south-east coast, NSW, Australia. A range of elements required for metabolism in photosynthetic organisms were also analysed to determine if any relationship between these elements and arsenic concentrations occurred. Organisms were selected from salt marsh and mangrove ecosystems, marine inter-tidal and estuarine environments, and two species of marine phytoplankton cultured, to represent the different marine environments that primary producers inhabit. Organisms selected were compared to species within their own environment and then a comparison made between the varying ecosystems. In the salt marsh and mangrove ecosystems, the leaves of four species, the mangrove Avicennia marina, the samphire Sarcocornia quinqueflora, the seablight Suaeda australis, and the seagrass Posidonia australis were sampled from three locations from the south-east coast of NSW using nested sampling. Mean total arsenic concentrations (mean � sd) dry mass for all locations were A. marina (0.38 � 0.18 �g g-1 to 1.2 � 0.7 �g g-1), S. quinqueflora (0.13 � 0.06 �g g-1 to 0.46 � 0.22 �g g-1), S. australis (0.03 � 0.06 �g g-1 to 0.05 � 0.03 �g g-1)and P. australis (0.34 � 0.10 �g g-1 to 0.65 � 0.26 �g g-1). Arsenic concentrations were significantly different between species and locations but were consistently low compared to marine macroalgae species. Significant relationships between As and Fe concentrations for A. marina, S. quinqueflora and P. australis and negative relationship between As and Zn concentrations for S. quinqueflora could partially explain arsenic concentrations in these species. No relationship between As and P concentrations were found in this study. All terrestrial species contained predominantly inorganic arsenic in the water extractable and residue fractions with minor concentrations of DMA in the water-soluble fraction. P. australis also contained dimethylated glycerol and phosphate arsenoriboses. The presence of arsenobetaine, arsenocholine and trimethylated glycerol arsonioribose is most likely due to the presence of epiphytes on fronds on P. australis. In contrast, macroalgae contained higher total arsenic concentrations compared to marine terrestrial angiosperms. Total arsenic concentrations also varied between classes of algae: red macroalgae 4.3 �g g-1 to 24.7 �g g-1, green macroalgae 8.0 �g g-1 to 11.0 �g g-1 and blue green algae 10.4 �g g-1 and 18.4 �g g-1. No significant relations were found between As concentrations and concentrations of Fe, Co, Cu, Mn, Mo, Mg, P and Zn concentrations, elements that are required by macroalgae for photosynthesis and growth. Distinct differences between algal classes were found for the proportion of arsenic species present in the lipid and water-soluble fractions, with green algae having a higher proportion of As in lipids than red or estuarine algae. Acid hydrolysis of the lipid extract revealed DMA, glycerol arsenoribose and TMA based arsenolipids. Within water-soluble extracts, red and blue-green algae contained a greater proportion of arsenic as inorganic and simple methylated arsenic species compared to green algae, which contained predominantly glycerol arsenoribose. Arsenobetaine, arsenocholine and tetramethylarsonium was also present in water-soluble extracts but is not normally identified with macroalgae and is again likely due to the presence of attached epiphytes. Residue extracts contained predominantly inorganic arsenic, most likely associated with insoluble constituents of the cell. Mean arsenic concentrations in the green microalgae Dunaliella tertiolecta were 13.3 �g g-1 to 14.5 �g g-1, which is similar to arsenic concentrations found in green macroalgae in this study. Diatom Phaeodactylum tricornutum arsenic concentrations were 1.62 �g g-1 to 2.08 �g g-1. Varying the orthophosphate concentrations had little effect on arsenic uptake of microalgae. D. tertiolecta and P. tricornutum metabolised arsenic, forming simple methylated arsenic species and arsenic riboses. The ratio of phosphate to glycerol arsenoriboses was higher than that normally found in green macroalgae. The hydrolysed lipid fraction contained DMA arsenolipid (16-96%) with minor proportions of phosphate arsenoribose (4-23%). D. tertiolecta at f/10 phosphate concentration, however, contained glycerol arsenoribose and another arsenic lipid with similar retention as TMAO as well as DMA. The similarities between arsenic species in the water-soluble hydrolysed lipids and water-soluble extracts, especially for P. tricornutum, suggests that cells readily bind arsenic within lipids, either for membrane structure or storage, releasing arsenic species into the cytosol as degradation of lipids occurs. Inorganic arsenic was sequestered into insoluble components of the cell. Arsenic species present in D. tertiolecta at lower phosphate concentrations (f/10) were different to other phosphate concentrations (f/2, f/5), and require further investigation to determine whether this is a species-specific response as a result of phosphate deficiency. Although there are similarities in arsenic concentrations and arsenic species in marine photosynthetic organisms, it is evident that response to environmental concentrations of arsenic in uncontaminated environments is dependent on the mode of transfer from the environment, the influence of other elements in arsenic uptake and the ability of the organism to metabolise and sequester inorganic arsenic within the cell. It is not scientifically sound to generalise on arsenic metabolism in �marine plants� when species and the ecosystem in which they exist may influence the transformation of arsenic in higher marine organisms. There is no evidence to suggest that angiosperms produce AB as arsenic is mostly present as inorganic As, with little or no arsenic present in the lipids. However, marine macro- and microalgae both contain lipids with arsenic moieties that may be precursors for AB transformation. Specifically, the presence of TMA and dimethylated arsenoribose based arsenolipids both can transform to AB via intermediates previously identified in marine organisms. Further identification and characterization of As containing lipids is required.

Listed as federally-endangered in 1990, the Lower Keys marsh rabbit (LKMR, Sylvilagus palustris hefneri) exists as a metapopulation in patches of wetland habitat in Florida’s Lower Keys. This study sought to address 2 priority actions identified by the LKMR Recovery Team: (1) monitoring of populations and (2) reintroduction. Monitoring the distribution and status of LKMR populations is critical for targeting future management actions. Informal transects for rabbit fecal pellets were used to survey habitat patches documented in1988–1995 surveys and to identify additional patches of occupied and potential habitat. Next, a buffer was created around patches to help managers account for uncertainty in rabbit movements and to identify groups of patches that might function as local populations. Surveys included 228 patches of occupied and potential habitat, 102 of which were occupied by rabbits. Patches were arranged in 56 occupied and 88 potential populations. Surveys revealed new patches of both occupied and potential habitat. Considering only areas included in 1988–1995 surveys, however, revealed a net decrease in the number of occupied patches. Many of the recently extirpated populations, which tended to occupy the periphery of larger islands or small neighboring islands, were unlikely to be recolonized without human intervention. Reintroduction provides a means of artificially recolonizing potential habitat. Two pilot reintroductions were conducted to evaluate this conservation strategy for the species. The second reintroduction was postponed, but the first effort met all criteria for short-term success, including survival comparable to a control group, fidelity to release sites, and evidence of reproduction. There are a limited number of potential source populations for translocations. Future efforts should consider using in-situ captive breeding to prevent potential long-term impacts to these populations. Few potential release sites exhibited suitable habitat quality and landscape context. Thus, for reintroduction to be more widely-applied for this species, it must be part of a comprehensive management plan involving land acquisition, control of secondary impacts from development, and habitat restoration and enhancement.

Listed as federally-endangered in 1990, the Lower Keys marsh rabbit (LKMR, Sylvilagus palustris hefneri) exists as a metapopulation in patches of wetland habitat in Florida’s Lower Keys. This study sought to address 2 priority actions identified by the LKMR Recovery Team: (1) monitoring of populations and (2) reintroduction. Monitoring the distribution and status of LKMR populations is critical for targeting future management actions. Informal transects for rabbit fecal pellets were used to survey habitat patches documented in1988–1995 surveys and to identify additional patches of occupied and potential habitat. Next, a buffer was created around patches to help managers account for uncertainty in rabbit movements and to identify groups of patches that might function as local populations. Surveys included 228 patches of occupied and potential habitat, 102 of which were occupied by rabbits. Patches were arranged in 56 occupied and 88 potential populations. Surveys revealed new patches of both occupied and potential habitat. Considering only areas included in 1988–1995 surveys, however, revealed a net decrease in the number of occupied patches. Many of the recently extirpated populations, which tended to occupy the periphery of larger islands or small neighboring islands, were unlikely to be recolonized without human intervention. Reintroduction provides a means of artificially recolonizing potential habitat. Two pilot reintroductions were conducted to evaluate this conservation strategy for the species. The second reintroduction was postponed, but the first effort met all criteria for short-term success, including survival comparable to a control group, fidelity to release sites, and evidence of reproduction. There are a limited number of potential source populations for translocations. Future efforts should consider using in-situ captive breeding to prevent potential long-term impacts to these populations. Few potential release sites exhibited suitable habitat quality and landscape context. Thus, for reintroduction to be more widely-applied for this species, it must be part of a comprehensive management plan involving land acquisition, control of secondary impacts from development, and habitat restoration and enhancement.

Rapid development and urbanization of the Lower Florida Keys in the last 30 years has fragmented the habitat of the Lower Keys marsh rabbit (Sylvilagus palustris hefneri) and threatened it with extinction. Current threats exist at multiple spatiotemporal scales and include threats due to development, invasive species, and global climate change. On Boca Chica Key, the Lower Keys marsh rabbit (LKMR) exists as a metapopulation on Naval Air Station-Key West (NASKW). I conducted a population viability analysis to determine the metapopulation's risk of extinction under multiple management scenarios by developing a spatially-explicit, stage-structured, stochastic matrix model using the programs RAMAS Metapop and ArcGIS. These management scenarios include clearance of airfield vegetation, habitat conversion, and control of feral cats as an invasive species. Model results provided the Navy with relative risk estimates under these different scenarios. Airfield clearance with habitat conversion increased extinction risk, but when coupled with feral cat control, risk was decreased. Because of the potential of sea-level rise due to human-induced global climate change, and its projected impact on the biodiversity of the Florida Keys, I estimated the impacts of rising sea levels on LKMR across its geographic distribution under scenarios of no, low (0.3m), medium (0.6m), and high (0.9m) sea-level rise. I also investigated impacts due to 2 treatments (allowing vegetation to migrate upslope and not allowing migration), and 2 land-use planning decisions (protection and abandonment of humandominated areas). Not surprisingly, under both treatments and both land-use planning decisions, I found a general trend of decreasing total potential LKMR habitat with increasing sea-level rise. Not allowing migration and protecting human-dominated areas both tended to decrease potential LKMR habitat as compared with allowing migration and abandoning human-dominated areas. In conclusion, conservation strategies at multiple scales need to be implemented in order to reduce threats to LKMR, such as development, invasive species, and global climate change.

Document formatted into pages; contains 46 pages. / Title from PDF of title page. / Thesis (M.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Herbivore abundances are determined by a set of interacting factors that vary among different habitat types. Specifically, herbivore abundances in monocultures and polycultures may be governed by the same set of factors but with varying influences in the different habitats. In addition, monophagous and polyphagous herbivores may respond differently to the same set of influencing factors. I examined several abiotic and biotic factors in manipulated monocultures and polycultures of Borrichia frutescens in a west central Florida salt marsh. The experimental plots differed in both plant diversity and aboveground habitat structure to see how each component of diversity contributed to variability in the abiotic and biotic factors and how those factors were related to differences in herbivore abundances. The monoculture treatment involved clipping all above ground non-host plant material to achieve a host plant monoculture. The polyculture treatments involved pinning all non-host plant material to achieve a polyculture with reduced above ground habitat structure. The second polyculture treatment was a control in which the naturally diverse plots were unmanipulated. Two monophagous and one polyphagous herbivores were chosen for this study because of their abundance and availability in the field. The two monophagous herbivores on the host plant Borrichia frutescens were Pissonotus quadripustulatus (Homoptera:Delphacidae) and Asphondylia borrichiae (Diptera: Cecidomyiidae) both of which have been well studied in the field where the current experiment took place. The polyphagous herbivore was Cyarda acutissima (Homoptera: Flatidae), a poorly known invasive from Cuba. Soil salinity and host plant leaf nitrogen content were the abiotic factors measured. Herbivore abundances, percent egg and gall parasitism by parasitoids, spider abundances on host plant stems and ground spider abundances were the biotic factors measured. Both salinity and host plant leaf nitrogen were significantly different among the different treatments with clipped plots having the highest salinity and leaf nitrogen content. Population densities of both of the monophagous herbivores were not significantly different between treatments. The polyphagous herbivore had significantly higher abundances in the pinned and control plots than in the clipped plots. Stem spider abundances were not significantly different among treatments. Ground spiders, however, were significantly more abundant in control and pinned plots than clipped plots. Parasitism of both monophagous herbivores was not significantly different between treatments but was generally higher in the control plots. The results suggest that for monophagous herbivores bottom-up and top-down factors act antagonistically in monocultures but for the polyphagous herbivore, the presence of multiple host plants is more influential in diverse plots even given the higher abundances of generalist predators. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

In 2011 Manitoba experienced an extreme flood. The operation of the Assiniboine River Diversion resulted in the addition of approximately 1.72 million cubic decameters of water to Lake Manitoba and an increase in water levels to 1.5 m above normal. Although this event resulted damage to farmland and many local homes, it also provided me the unique opportunity to utilize previously impractical methods of bathymetric and substrata distribution analysis in the adjoining Delta Marsh. Combined with satellite imagery taken in 2011 I was able to classify the vegetation classes within the study area and explore the relationship between vegetation distributions and water depth as well as those between water depth and substrata distribution. A seed bank study was carried out to explore the diversity of viable seeds in the area. In addition, satellite imagery taken in 2009 was used to evaluate the effects of the flood event experienced in 2011. / October 2015

Populations of black mangroves (Avicennia sp.) are hypothesized to expand their latitudinal range with global climate change in the 21st century, induced by a reduction in the frequency and severity of coastal freezes, which are known to limit mangrove colony extent and individual tree size, as well as an overall warmer climate. The Gulf of Mexico is located at the northward limit of black mangrove habitat and is therefore a prime candidate for population expansion with global warming. This expansion may come at the expense of existing Gulf coastal saline wetlands that are dominantly Spartina spp. marsh grasses. The present study was conducted to focus, not on the extent to date of this replacement, but to examine the potential implications of a marsh to mangrove transition in Gulf wetlands, specifically 1) resistance to accelerating eustatic sea level rise (ESLR) rates, 2) wetland resistance to wave attack in large storms (increased cyclonic storm frequency/intensity is predicted with future climate warming), and 3) organic carbon sequestration and wetland soil geochemistry. Field sites of adjacent and intergrown Avicennia mangrove and Spartina marsh populations in similar geomorphological setting were selected in back-barrier areas near Port Aransas and Galveston, TX (two sites each) as part of a larger-scale planned study of the full latitudinal transition of the western Gulf funded by the National Institute for Climate Change Research (U.S. Department of Energy). The reconnaissance conducted for site surveys show that black mangrove populations in this part of Texas are clustered near inlet areas, suggesting seed transport vectors are a major control on colony establishment, and likely, on the potential rapidity of wetland habitat replacement. Resistance to ESLR was tested by 1) creating high-accuracy (±1 cm) elevation maps over ~5,000 m² areas of adjacent mangrove and marsh areas, and 2) measuring mineral and organic matter accumulation rates (Pb/Cs radiotracer geochronology, loss on ignition) from auger cores. Elevation surveys in Port Aransas indicate mangrove vegetated areas are 4 cm higher in elevation than surrounding marsh on an average regional scale, and 1 to 2 cm higher at the individual mangrove scale: at the Galveston sites, any trend is complicated by the area's pre-existing geomorphology and the relative youth of the mangrove colonies. ¹³⁷Cs accumulation rates and loss on ignition data indicate that mineral trapping is 4.1 times higher and sediment organics are 1.7 times lower in mangroves at Port Aransas; no such definable trends exist at the Galveston sites or in calculated ²¹⁰Pb sediment accumulation rates. This additional mineral particle trapping in mangroves does not differ in grain size character from marsh mineral accumulation. Elevation change may also be effected by root volume displacement: live root weight measurements in the rooted horizon (~0 to 20 cm depth) are consistently higher in mangrove cores from Port Aransas and the site at the west end of Galveston Island. Port Aransas porosities are lower in mangrove rooted horizons, with a corresponding increase in sediment strength (measured by shear vane in the cores), suggesting mangrove intervals may be more resistant to wave-induced erosion during storm events. Port Aransas mangroves exhibit higher pore water redox potentials and salinities over entire core depths and depressed pH over rooted intervals, suggesting a distinct diagenetic environment exists relative to marsh sites. Increased salinities and higher redox potentials may be a function of the rooting network, which introduces oxygen into the sediment and focuses evapo-transpiration and salt exclusion within this zone: this may prove advantageous when competing with marsh grasses by elevating salinities to levels that are toxic for Spartina. Trends observed in the more mature systems of Port Aransas are generally absent at the Galveston sites, suggesting the youth and physically shorter stature of these systems means they have not yet established a unique sediment signature. / text

Pertinent abiotic and biotic factors and their interdependencies necessary to comprehend the ecology of saline systems are investigated and evaluated. A designed saline ecosystem is proposed as a constructive method to reduce waste volume. Landscape pattern is investigated as the vehicle for an evapotranspiration induced directional saline gradient. A demonstration site is used to explore conceptual design application of the idea of ecosystem pattern consisting of a linear sequence of ecotopes, each displaying its own ecological community in relation to salinity range and site context. Biota is relinquished to self-organization. Potential for research use of the ecosystem is illustrated.