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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Application of Biomarkers and Compound Specific Stable Isotopes for the Assessment of Hydrology as a Driver of Organic Matter Dynamics in the Everglades Ecosystem

He, Ding 25 June 2014 (has links)
The Everglades is a sub-tropical coastal wetland characterized among others by its hydrological features and deposits of peat. Formation and preservation of organic matter in soils and sediments in this wetland ecosystem is critical for its sustainability and hydrological processes are important divers in the origin, transport and fate of organic matter. With this in mind, organic matter dynamics in the greater Florida Everglades was studied though various organic geochemistry techniques, especially biomarkers, bulk and compound specific δ13C and δD isotope analysis. The main objectives were focused on how different hydrological regimes in this ecosystem control organic matter dynamics, such as the mobilization of particulate organic matter (POM) in freshwater marshes and estuaries, and how organic geochemistry techniques can be applied to reconstruct Everglades paleo-hydrology. For this purpose organic matter in typical vegetation, floc, surface soils, soil cores, and estuarine suspended particulates were characterized in samples selected along hydrological gradients in the Water Conservation Area 3, Shark River Slough and Taylor Slough. This research focused on three general themes: (1) Assessment of the environmental dynamics and source-specific particulate organic carbon export in a mangrove-dominated estuary. (2) Assessment of the origin, transport and fate of organic matter in freshwater marsh. (3) Assessment of historical changes in hydrological conditions in the Everglades (paleo-hydrology) though biomarkes and compound specific isotope analyses. This study reports the first estimate of particulate organic carbon loss from mangrove ecosystems in the Everglades, provides evidence for particulate organic matter transport with regards to the formation of ridge and slough landscapes in the Everglades, and demonstrates the applicability of the combined biomarker and compound-specific stable isotope approach as a means to generate paleohydrological data in wetlands. The data suggests that: (1) Carbon loss from mangrove estuaries is roughly split 50/50 between dissolved and particulate carbon; (2) hydrological remobilization of particulate organic matter from slough to ridge environments may play an important role in the maintenance of the Everglades freshwater landscape; and (3) Historical changes in hydrology have resulted in significant vegetation shifts from historical slough type vegetation to present ridge type vegetation.
112

Examining Movement and Habitat Selection of Everglades Fishes in Response to Seasonal Water levels

Hill, Gregory J 10 March 2017 (has links)
Fish distribution patterns and seasonal habitat use play a key role in the food web dynamics of aquatic ecosystems, including the Florida Everglades. In this study I examined the fine scale habitat shifts and movements of spotted sunfish, Lepomis punctatus across varying seasons and hydrologic conditions using in-situ field enclosures and Passive Integrated Transponder (PIT) systems. Data on fish use of three dominant Everglades marsh habitats and activity level were recorded continuously from January to August, 2015. Fish were more active and had the highest use of higher elevation habitats when water levels rose during an experimental reversal in mid-April. Fish activity was higher at increasing water levels relative to decreasing. Fish activity also varied with the rate of change, with the highest activity occurring during rapid increases in depth. Findings from this study provide insight on how fish response to changing water levels may affect foraging for wading birds, a key performance measure for Everglades restoration.
113

Recreational Angler Perspectives of Nonnative Fish Species and Mercury Advisories

Edwards, Christopher J. 15 November 2013 (has links)
The central Everglades serve as a Wildlife Management Area and as a Water Conservation Area for the Miami-Fort Lauderdale metropolitan area. It is also home to over 22 nonnative freshwater fish species and carries restrictive fish consumption guidelines for Mercury. In my study, boat anglers and canal bank anglers were personally interviewed in the field, to research their awareness and perspectives of these potential environmental and health threats. The study found 78% of anglers were aware of the presence of nonnative fish species, but favored native fish species, and that 69% were aware of mercury advisories, but did not eat fewer fish because of them. Demographic characteristics were found to predict awareness, which differed significantly between angler types. Public awareness campaigns of nonnative fish impacts should target high school educated, canal bank anglers while mercury advisories should be directed at canal bank anglers, who typically keep and consume their catch more than boat anglers, to those who live more than 30 miles from the area, and all anglers under the age of 48.
114

The Interactive Effects of Predators, Resources, and Disturbance on Freshwater Snail Populations from the Everglades

Ruehl, Clifton B 23 April 2010 (has links)
The origins of population dynamics depend on interplay between abiotic and biotic factors; the relative importance of each changing across space and time. Predation is a central feature of ecological communities that removes individuals (consumption) and alters prey traits (non-consumptive). Resource quality mitigates non-consumptive predator effects by stimulating growth and reproduction. Disturbance resets predator-prey interactions by removing both. I integrate experiments, time-series analysis, and performance trials to examine the relative importance of these on the population dynamics of a snail species by studying a variety of their traits. A review of ninety-three published articles revealed that snail abundance was much less in the Everglades and similar ecosystems compared to all other freshwater ecosystems considered. Separating consumptive from non-consumptive (cues) predator effects at different phosphorous levels with an experiment determined that phosphorous stimulated, but predator cues inhibited snail growth (34% vs. 23%), activity (38% vs. 53%), and reproductive effort (99% vs. 90%) compared to controls. Cues induced taller shells and smaller openings and moved to refugia where they reduced periphyton by 8%. Consumptive predator effects were minor in comparison. In a reciprocal transplant cage experiment along a predator cue and phosphorous gradient created by a canal, snails grew 10% faster and produced 37% more eggs far from the canal (fewer cues) when fed phosphorous-enriched periphyton from near the canal. Time-series analysis at four sites and predator performance trials reveal that phosphorous-enriched regions support larger snail populations, seasonal drying removes snails at all sites, crayfish negatively affect populations in enriched regions, and molluscivorous fish consume snails in the wet season. Combining these studies reveals interplay between resources, predators, and seasonality that limit snail populations in the Everglades and lead to their low abundance compared to other freshwater ecosystems. Resource quality is emerging as the critical factor because improving resources profoundly improved growth and reproduction; seasonal drying and predation become important at times and places. This work contributes to the general understanding in ecology of the relative importance of different factors that structure populations and provides evidence that bolsters monitoring efforts to assess the Comprehensive Everglades Restoration Plan that show phosphorous enrichment is a major driver of ecosystem change.
115

Water and Soil Salinity Mapping for Southern Everglades using Remote Sensing Techniques and In Situ Observations

Unknown Date (has links)
Everglades National Park is a hydro-ecologically significant wetland experiencing salinity ingress over the years. This motivated our study to map water salinity using a spatially weighted optimization model (SWOM); and soil salinity using land cover classes and EC thresholds. SWOM was calibrated and validated at 3-km grids with actual salinity for 1998–2001, and yielded acceptable R2 (0.89-0.92) and RMSE (1.73-1.92 ppt). Afterwards, seasonal water salinity mapping for 1996–97, 2004–05, and 2016 was carried out. For soil salinity mapping, supervised land cover classification was firstly carried out for 1996, 2000, 2006, 2010 and 2015; with the first four providing average accuracies of 82%-94% against existing NLCD classifications. The land cover classes and EC thresholds helped mapping four soil salinity classes namely, the non saline (EC = 0~2 dS/m), low saline (EC = 2~4 dS/m), moderate saline (EC = 4~8 dS/m) and high saline (EC >8 dS/m) areas. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
116

Water Table and Nutrient Dynamics in Neotropical Savannas and Wetland Ecosystems

Villalobos-Vega, Randol 07 May 2010 (has links)
The Tropical savannas of central Brazil (cerrado) and the Everglades wetland (Florida) ecosystems are ideal systems to study landscape spatial mosaics and their interactions. Both ecosystems show a variety of plant physiognomies distributed within small spatial scales and elevation gradients. Such variety of plant physiognomies provide an opportunity to investigate the roles of climate, topography, nutrient availability and water table dynamics as determinants of plant physiognomic distributions, and their role in shaping regional systems. South Florida Wetlands and the tropical savannas of central Brazil are examples of hydrologically-controlled ecosystems. In hydrologically-controlled ecosystems water sources, the availability of nutrients, and the patterns of water movement play important roles in determining vegetation structure and function. The main objective of this study was to understand ecosystem level processes that shape different physiognomies in two hydrologically-controlled ecosystems. I conducted field work at the IBGE ecological reserve, a field experimental station located in Brasilia, Brazil. I also worked at the Everglades National Park in an area located near the south entrance of the Park in Homestead, Florida. I carried out three interconnected studies investigating water and nutrient dynamics: (1) In a Brazilian savanna I manipulated levels of litter input and measured changes to soil properties, organic matter decomposition and tree growth. I found that changes in litter input affect soil physicochemical properties and soil biochemical processes. I also found that litter dynamics influence tree growth through their effects on soil physicochemical properties. (2) I also studied the effect of water table depth and its temporal variation on spatial patterns of vegetation distribution in the cerrado landscape. I monitored diurnal and seasonal changes in water table depth along two tree-density and topographic gradients. In addition, I measured woody species composition, growth rates of four tree species, litter production, soil nutrients, and nutrient resorption efficiency along those two gradients. I found that water table depth has an important role in determining the spatial distribution of cerrado physiognomies; it also affects tree growth, species composition and nutrient resorption efficiency. (3) In the Everglades I studied patterns of underground water uptake by two vegetation types. I monitored seasonal and diurnal changes in water table depth in a Hammock forest, in a stand dominated by the invasive woody species Schinus terebinthifolius, as well as the water level in an adjacent lake. I estimated stand level transpiration using two different approaches: with sap flow measurements and diurnal oscillations in water table levels. Then, I calculated the total quantity of groundwater withdrawn by evapotranspiration for the wet and dry seasons in the Hammocks and in the exotic invaded site and then compared the results. I found that water uptake by Everglades trees is well coupled to diurnal changes in water table depth and that the amount of water withdrawn from the groundwater was larger during the wet season than during the dry season. Finally, I detected hydrological feedbacks between different vegetation types and nearby bodies of water. Results of this study contributes to the current knowledge of ecosystem level processes in tropical and subtropical ecosystems where water circulation and water availability play a dominant role in shaping vegetation structure and function.
117

Sentidos e significados (significa??es) atribu?dos pelos povos ? sa?de e o processo de implanta??o do Parque Nacional das Sempre-vivas: ?sofrimento ? oc? n?o ter liberdade?

Reis, Aremita Aparecida Vieira dos 05 February 2018 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-09-17T21:02:51Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aremita_aparecida_vieira_reis.pdf: 2418281 bytes, checksum: 67deea14d94e0a30cc247899cc0b1807 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-10-01T18:59:10Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aremita_aparecida_vieira_reis.pdf: 2418281 bytes, checksum: 67deea14d94e0a30cc247899cc0b1807 (MD5) / Made available in DSpace on 2018-10-01T18:59:10Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aremita_aparecida_vieira_reis.pdf: 2418281 bytes, checksum: 67deea14d94e0a30cc247899cc0b1807 (MD5) Previous issue date: 2018 / A pesquisa trata de reflex?es qualitativas de campo que t?m a Psicologia S?cio Hist?rica como eixo epistemol?gico norteador e que tem como objetivo geral: levantar, analisar e desvelar os sentidos e significados (significa??es) que as comunidades tradicionais atribuem ao processo sa?de-doen?a e ? implanta??o do Parque Nacional das Sempre-vivas. Como objetivos espec?ficos: verificar, analisar e desvelar qual a concep??o que os povos tradicionais que residem na ?rea de abrang?ncia do Parque Nacional das Sempre-vivas t?m acerca do processo sa?de-doen?a; verificar, analisar e desvelar se os povos tradicionais que residem na ?rea de abrang?ncia do Parque Nacional das Sempre-vivas correlacionam o processo de sa?de-doen?a com a implanta??o do Parque Nacional das Sempre-vivas; verificar, analisar e desvelar, quais os sentidos e significados atribu?dos ? implanta??o do Parque Nacional das Sempre-vivas pelos povos tradicionais que residem na ?rea de abrang?ncia do mesmo. A pesquisa foi realizada na ?rea de abrang?ncia do Parque Nacional das Sempre-vivas localizado na regi?o nordeste do estado de Minas Gerais. Para a constru??o desse estudo, tr?s mulheres representantes de distintas comunidades foram entrevistadas. A entrevista semiestruturada centralizada e recorrente foi a t?cnica de obten??o das informa??es. ? an?lise de N?cleos de Significa??es e a an?lise dos N?cleos Tem?ticos foram as estrat?gias anal?ticas utilizadas. Todos os preceitos ?ticos da Resolu??o 466/12 foram acatados e garantidos. Ao buscar desvelar a rela??o entre o Parque Nacional das Sempre-vivas e o processo de adoecimento dos povos afetados foi necess?rio entender de onde vinham os conhecimentos e as pr?ticas relacionados aos cuidados de sa?de, qual a concep??o de sa?de-doen?a adotada por esses povos, essa busca nos conduziu ?s av?s, bisav?s, tatarav?s detentoras dos conhecimentos e praticas relacionado aos cuidados da sa?de, nas quais resguardam um patrim?nio social carregado de significa??es atribu?das pelos povos nativos destas terras. Constatamos que a sobreposi??o do Parque Nacional das Sempre-vivas em terras tradicionalmente ocupadas provocou sofrimento ps?quico desencadeado pelo medo e aos atos de viol?ncia a que foram submetidos, al?m disso, a repress?o das atividades das popula??es habitantes representa o rompimento com o existir desses povos e como consequ?ncia, leva ao adoecimento. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Sa?de, Sociedade e Ambiente, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2018. / The research deals with qualitative field reflections that have Historical Partner Psychology as a guiding epistemological axis and whose general objective is: to raise, analyze and reveal the meanings and meanings (meaning) that traditional communities attribute to the health-disease process and the implantation of the Evergreens National Park. As specific objectives: to verify, analyze and unveil the conception that the traditional peoples that reside in the area of coverage of the Everglades National Park have about the health-disease process; verify, analyze and reveal if the traditional peoples who live in the area covered by the Everglades National Park correlate the health-disease process with the implementation of the Evergreen National Park; verify, analyze and reveal the meanings and meanings attributed to the implantation of the Evergreen National Park by the traditional peoples residing in the area covered by it. The research was carried out in the area covered by the Evergreen National Park located in the northeastern region of the state of Minas Gerais. For the construction of this study, three women representatives from different communities were interviewed. The centralized and recurrent semi-structured interview was the technique of obtaining the information. The analysis of Nuclei of Meanings and the analysis of the Thematic Nuclei were the analytical strategies used. All the ethical precepts of Resolution 466/12 were adhered to and guaranteed. In seeking to unveil the relationship between Evergreens National Park and the disease process of affected peoples, it was necessary to understand where the knowledge and practices related to health care came from, what the concept of health-disease adopted by these peoples, this search led us to the grandparents, great-grandparents, great-grandparents holding the knowledge and practices related to health care, in which they safeguard a social patrimony loaded with meanings attributed by the native peoples of these lands. We find that the overlapping of the Evergreen National Park in traditionally occupied lands caused psychic suffering triggered by the fear and acts of violence to which they were subjected. In addition, the repression of the activities of the inhabitants represents the rupture with the existence of these peoples and as a consequence, leads to illness.
118

Habitat and Seasonal Distribution of the North American River Otter (Lontra canadensis) and Vertebrate Species Assemblages in Two Protected Areas of the Florida Everglades

Hamilton, Catherine Faye 01 November 2014 (has links)
The Florida Everglades ecosystem is threatened by human development, increased pollution, freshwater scarcity, and invasive species; factors that have negatively impacted the Everglades and native species health and populations. Man-made canals and levies have redirected the natural flow of fresh water from Lake Okeechobee into the Florida Everglades, starving central and south Florida ecosystems of necessary fresh water and nutrients. Through the efforts of the Comprehensive Everglades Restoration Project (CERP), freshwater is being redirected back into central and south Florida, returning the sheet flow of water back into the Everglades. Monitoring species abundance in the Everglades is a beneficial conservational tool for assessing restoration efforts from CERP. As a semi-aquatic apex predator, river otters (Lontra canadensis) are a useful health bio-indicator for the Florida Everglades. In order to conduct future population studies of river otters in the Florida Everglades, it must first be ascertained where they can be found and what time of year they are most likely to be sighted. For this study, Moultrie infrared game cameras were used to photograph the presence or absence of river otters within the five main habitats in the Everglades; the pinelands, hardwood hammock, cypress swamp, marsh prairie, and mangrove estuary at two protected areas in the Florida Everglades (Big Cypress National Preserve and Fakahatchee Strand State Park). River otters were most frequently sighted in the hardwood hammock habitat, but were also found in the cypress swamp. The large majority of river otter sightings occurred during dry season, which is thought to be a function of restricted water availability and aquatic mobility. Future population studies of river otters would be most productive in the hardwood hammock and cypress swamp habitats during dry season. Game camera images along with field opportunistic sightings, resulted in a variety of species documented. This provided valuable information of species richness and distribution within and amongst the habitats. The hardwood hammock was found to be the most species rich habitat, having over half the species observed in the study in this habitat. The Aves class was the most abundantly observed in the Everglades, and was most frequently sighted during the dry season. As a refuge for migratory birds, the Everglades house the majority of bird species during the winter months, which occur during dry season. The Aves class was most frequently sighted in the pinelands habitat during dry season. This habitat, being the highest in elevation and therefore the driest, shows a stronger resemblance to most northern bird habitats then does the water-saturated wetlands found throughout the Everglades. The mangrove estuary was the most commonly occurring outlier, having the least species overlap when compared to the other habitats. All other habitats in the Everglades are freshwater wetlands, while the mangrove estuary is a brackish environment, which limits the species that are unable to tolerate saline conditions. Further studies of species abundance throughout the Everglades will aid in monitoring CERP restoration efforts over time.
119

Numerical Modeling of the Effects of Hydrologic Conditions and Sediment Transport on Geomorphic Patterns in Wetlands

Mahmoudi, Mehrnoosh 30 September 2014 (has links)
This dissertation focused on developing a numerical model of spatial and temporal changes in bed morphology of ridge and slough features in wetlands with respect to hydrology and sediment transport when a sudden change in hydrologic condition occurs. The specific objectives of this research were: (1) developing a two-dimensional hydrology model to simulate the spatial distribution of flow depth and velocity over time when a pulsed flow condition is applied, (2) developing a process-based numerical model of sediment transport coupled with flow depth and velocity in wetland ecosystems, and (3) use the developed model to explore how sediment transport may affect the changes in bed elevation of ridge and slough landscape patterns observed in wetlands when a conditional pulsed flow was applied. The results revealed the areas within deep sloughs where flow velocities and directions change continuously. This caused enhanced mixing areas within the deep slough. These mixing areas may have had the potential to affect processes such as sediment redistribution and nutrient transport. The simulation results of solute/sediment transport model also supported the existence of areas within the domain where the mixing processes happened. These areas may have caused that nutrients and suspended particles stay longer time rather than entraining toward downstream and exiting the system. The results of bed simulation have shown very small magnitude of change in bed elevation inside deep slough and no changes on the ridge portion of the study area, when a conditional pulsed flow is applied. These findings may suggest that implementing pulsed flow condition did not increase suspended sediment concentration, which results in insignificant changes in bed morphology of a ridge and slough landscape. Therefore sediment transport may not play an important role in wetland bed morphology and ridge and slough stability. Results from the model development and numerical simulations from this research will provide an improved understanding of how wetland features such as ridge may have formed and degraded by changes in water management that resulted from increasing human activity in wetlands such as The Florida Everglades, over the past decades.
120

Studium autekologie vybraných taxonů křídových rostlin pomocí izotopů uhlíku / Autecological study of selected Cretaceous plants using stable Carbon isotopes

Zahajská, Petra January 2016 (has links)
1 Abstract This thesis presents an analysis of fossil plants from the Cenomanian Peruc-Korycany Formation of the Bohemian Cretaceous Basin and from the Bückeberg Formation of the Lower Saxony Basin in Germany. Based on earlier studies, both areas provide sediments that are considered to have developed in tidally influenced fluvial systems. Studied fossil plants are represented by ginkgoalean plant leaves (Ertemophyllum, Tritaenia), branches of conifers (Frenelopsis) and lauroid angiosperms (Eucalyptolaurus). Frenelopsis, Eretmophyllum and Tritaenia are considered to be halophytic plants, while Lauroid angiosperms were considered to grow in fresh water conditions. The fossil plants were studied using cuticle analysis and two methods of stable carbon isotope analysis: Bulk carbon isotope analysis and Compound Specific Isotope analysis. For cuticle analysis samples were observed and documented macroscopically and microscopically. To specify the environmental conditions, recent samples from three salt marshes in Great Britain were studied and analysed using the same methods as the fossil samples. The data from all observations and measurements were processed and their interpretation supported the modelled environment based on the sedimentological data. Frenelopsis were growing in a haline environment with low...

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