Rozprawy doktorskie na temat „Coastal wetlands”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Coastal wetlands.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Coastal wetlands”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Compte, Ciurana Jordi. "Food webs of Mediterranean coastal wetlands". Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/7879.
Pełny tekst źródłaStreszczenie:
En aquesta tesi doctoral s'han estudiat els efectes directes i indirectes de dos tipus d'espècies claus de la comunitat aquàtica dels aiguamolls de l'Empordà (aiguamolls costaners mediterranis amb una xarxa tròfica senzilla). S'han realitzat experiments al camp utilitzant microcosmos i mesocosmos i els resultats han estat analitzats mitjançant tres aproximacions: la taxonòmica, la funcional i la de mides. S'ha comprovat que en situacions amb absència de predadors i dominància d'una única espècie en el zooplàncton (en aquest cas Calanipeda aquaedulcis i Daphnia magna), la segregació del recurs entre els diferents estadis de desenvolupament de la mateixa espècie zooplanctònica és una estratègia per evitar la competència intraespecífica en condicions de limitació de recurs. Per altra banda, la presència de diferents top-predators a la comunitat aquàtica (en aquest cas la medusa Odessia maeotica i el peix Aphanius iberus) desencadena una cascada tròfica en el plàncton però amb efectes top-down diferents segons el top-predator.In this PhD, direct and indirect effects of key species were studied in the aquatic community of the Empordà wetlands (Mediterranean coastal wetlands with a simple food web). Different field experiments were carried out using microcosms and mesocosms. To analyze the results, three approaches were used: taxonomic, functional and size-based. Results obtained from the experiments confirm that, in situation with absence of predator and dominance of single zooplanktonic specie (in this case Calanipeda aquaedulcis and Daphnia magna), resource partitioning among different developmental stages of same zooplanktonic specie is a strategy to reduce the intraespecific competence when the resource is limiting. On the other hand, the presence of different top-predators in aquatic community (in this case the jellyfish Odessia maeotica and the Iberian toothcarp Aphanius iberus) triggers a trophic cascade in plankton, however they have different top-down effects according to top-predator.
2
Trobajo, Pujadas Rosa. "Ecological analysis of periphytic diatoms in Mediterranean coastal wetlands (Empordà wetlands, NE Spain)". Doctoral thesis, Universitat de Girona, 2003. http://hdl.handle.net/10803/7661.
Pełny tekst źródłaStreszczenie:
S'han estudiat els efectes dels factors ambientals sobre el perífiton dels sistemes lenític fluctuants del aiguamolls de l'Empordà. L'estudi s'ha realitzat als tres nivells d'integració: nivell d'ecosistema considerant el rol del perífiton envers els altres productors primaris; a nivell de comunitat, estudiant la composició específica de les diatomees i a nivell de població estudiant la plasticitat fenotípica d'una espècie de diatomea (Nitzschia frustulum).A nivell d'ecosistema s'observa que els factors que afavoreixen el predomini dels diferents tipus de productors primaris (perífiton, fitoplàncton i macròfits) són la renovació i el grau d'eutròfia de l'aigua. A nivell de comunitat els factors determinants en la composició i distribució de les espècies de diatomees són els gradients confinament-inundació així com la productivitat del sistema. En funció d'aquest factors s'han establert 5 associacions de diatomees. A nivell de població es demostra que tant la salinitat, com la relació N : P a l'aigua com el moviment de l'aigua afecten la morfologia i ultraestructura de la valva de N. frustulum. De forma interessant s'observa que la salinitat, considerada com a factor individual, afecta N. frustulum a nivell poblacional provocant-li modificacions en la morfologia de la valva, per en canvi, no afecta a nivell de comunitat, ja que totes les espècies de diatomees presents en ambients de salinitat fluctuant són eurihalines.
The effects of environmental conditions on periphytic of lentic and fluctuating waters (Empordà wetlands) at the three different levels of organisation were studied: at ecosystem level, considering the role of periphyton among the primary producers; at community level, analysing the periphytic diatom species composition; and at population level studying the phenotypic plasticity of a selected diatom species (Nitzschia frustulum). The factors favouring the predominance of different primary productors (periphyton, phytoplankton and macrophytes) were the turnover and eutrophy of the water. At the community level, we observed that the main factors affecting diatom species composition and distribution are the gradients confinement-flooding and productivity of the system. Based on these factors 5 diatom assemblages have been distinguished. At the population level, the results of the present thesis proved that the morphology and ultrastructure of N. frustulum is affected by salinity, N : P ratio and movement of the water. Interestingly the results showed that salinity, as a single environmental factor, has effect at N. frustulum population level resulting in phenotypic plasticity while there is no effect of salinity at diatom community level since in such environments with fluctuating salinity all the species present are euryhaline.
3
Pyo, Hee-Dong. "An economic evaluation of coastal wetlands in Korea". Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343390.
Pełny tekst źródłaStreszczenie:
AN ECONOMIC EVALUATION OF COASTAL \VETLANDS IN KOREA BY IIEE-DONG PYO The thesis undertakes a detailed economic analysis of the coastal wetlands of Korea and applies the double-bounded dichotomous choice model and spike model of the contingent valuation method to systematically evaluate their conservation value. Further analysis including an extension of the original spike model using only singlcbounded data (Kristrom, I ()(n) to modelling double-bounded data for more statistical efficiency to deal with /.ero observations was made. As a result, the estimated willingness-to-pay for conserving the coastal wetlands under the study is S3.9 per month per household, and the annual aggregated conservation value for the entire nation is about 175 million dollars in a conservative scenario. The study then applies a benefit-cost analysis (8C';\) to coastal wetlands around the Youngsan River, an area of dispute between development and preservation in Korea, with a synthesised estimation of the ecosystcm functional values for coastal wetlands and rice paddies developed by reclamation. The results show wetland development would be preferred to its preservation in an optimistic seenano and conventional BC A, yielding NPV of $49million at the discount rate of 8(Yo, IRR of 8.28%, and B/C ratio of 1.03. By contrast, a normal scenario rejects economic feasibility for the development project at the discount rate of 8°/c), yielding a NPV of -$271 million, IRR of 6.5% and B/C ratio of 0.84. With an extended Be A including conservation values for I-year, 5-year and 1 O-year payment, the estimates of IRR are 7.42%, 5.42%, and 4.06%, respectively under the optimistic scenario. Meanwhile, under the nOnllal Scenario the estimates of IRR arc 5.85%, 4.25%, and 3.09%, respectively. In addition, this study includes a discussion of a comprehensiYe review of conjoint analysis and the integrated environmental management of coastal wetlands developing sustainability indicators for coastal lisheries using bio-economic models in Appendix.
4
Ouyang, Xiaoguang. "Exploring Carbon Mineralisation and Burial in Coastal Wetlands". Thesis, Griffith University, 2017. http://hdl.handle.net/10072/370678.
Pełny tekst źródłaStreszczenie:
Mangroves and saltmarshes are ‘blue carbon’ ecosystems and studies on their carbon (C) dynamics have become highly topical. In these coastal wetlands, the aboveground biomass sequesters C and allocates C to belowground roots. A significant portion of aboveground biomass is transferred to the sediment as litterfall. Belowground roots and their exudates are ultimately decomposed by microbial communities. As the product of root decomposition, CO2 is released from the sediment surface and organic C (OC) contributes to sediment C burial. In addition, the decomposition of litter and sediment organic material also contributes to CO2 efflux from the sediment surface. The patterns of belowground C dynamics in blue C ecosystems remain unclear, especially sediment C burial, root C decomposition, and the relative contributions of different sources to sediment CO2 efflux. Further, sediment CO2 efflux and C storage have typically been examined separately in past research. Improved understanding of these patterns will help consolidate the theory of C cycling in coastal wetlands and facilitate effective ‘blue C’ management. My thesis aims to fill these gaps via systematic quantitative reviews and synthesis of literature data, field surveys and laboratory microcosm experiments.
Studies on C stock in saltmarsh sediments have increased since the previous major review (Chmura et al., 2003). However, uncertainties exist in estimating global carbon storage in these vulnerable coastal habitats, thus hindering the assessment of their importance. Combining direct data and indirect estimation, my thesis compiled studies involving 143 sites across the southern and northern hemispheres, and provides an updated estimate of the global average carbon accumulation rate (CAR) at 244.7 g C m-2 yr-1 in saltmarsh sediments. Based on region-specific CAR and estimates of saltmarsh area in various geographic regions between 40°S to 69.7°N, total CAR in global saltmarsh sediments is estimated at ~ 10.2 Tg C yr-1. Latitude, tidal range and elevation appear to be important drivers for CAR of saltmarsh sediments, with considerable variation among different biogeographic regions. The data indicate that while the capacity for carbon sequestration by saltmarsh sediments ranked the first amongst coastal wetland and forested terrestrial ecosystems, their carbon budget was the smallest due to their limited and declining global areal extent. However, some uncertainties remain for this global estimate owing to limited data availability.
One of the aims of this thesis was to determine the drivers of root decomposition and its role in C budgets in mangroves and saltmarsh: the patterns of root decomposition, and its contribution to C budgets, in mangroves and saltmarsh. The impact of climatic (temperature and precipitation), geographic (latitude), temporal (decay period) and biotic (ecosystem type) drivers was explored using multiple regression models. Best-fit models explain 50% and 48% of the variance in mangrove and saltmarsh root decay rates, respectively. A combination of biotic, climatic, geographic and temporal drivers influence root decay rates. Rainfall and latitude have the strongest influence on root decomposition rates in saltmarsh. For mangroves, forest type is the most important; decomposition is faster in riverine mangroves than other types. Mangrove species Avicennia marina and saltmarsh species Spartina maritima and Phragmites australis have the highest root decomposition rates. Root decomposition rates of mangroves were slightly higher in the Indo-west Pacific region (average 0.16 % day-1) than in the Atlantic-east Pacific region (0.13 % day-1). Mangrove root decomposition rates also show a negative exponential relationship with porewater salinity. In mangroves, global root decomposition rates are 0.15 % day-1 based on the median value of rates in individual studies (and 0.14 % day-1 after adjusting for area of mangroves at different latitudes). In saltmarsh, global root decomposition rates average 0.12 % day-1 (no adjustment for area with latitude necessary). The global estimate of the amount of root decomposing is 10 Tg C yr-1 in mangroves (8 Tg C yr-1 adjusted for area by latitude) and 31 Tg C yr-1 in saltmarsh. Local root C burial rates reported herein are 51-54 g C m-2 yr-1 for mangroves (58-61 Tg C yr-1 adjusted for area by latitude) and 191 g C m-2 yr-1 for saltmarsh. These values account for 24.1-29.1% (mangroves) and 77.9% (saltmarsh) of the reported sediment C accumulation rates in these habitats. Globally, dead root C production is the significant source of stored sediment C in mangroves and saltmarsh.
Mangroves are blue carbon ecosystems that sequester significant carbon but release CO2, and to a lesser extent CH4, from the sediment through oxidation of organic carbon or from overlying water when flooded. Previous studies, e.g. Leopold et al. (2015), have investigated sediment organic C (SOC) content and CO2 flux separately, but did not provide a holistic perspective for both components of blue carbon. Based on field data from a mangrove in southeast Queensland, Australia, this thesis used a structural equation model to elucidate (1) the biotic and abiotic drivers of surface SOC (10 cm) and sediment CO2 flux; (2) the effect of SOC on sediment CO2 flux; and (3) the covariation among the environmental drivers assessed. Sediment water content, the percentage of fine-grained sediment (<63μm), surface sediment chlorophyll and light condition collectively drive sediment CO2 flux, explaining 41% of their variation. Sediment water content, the percentage of fine sediment, season, landform setting, mangrove species, sediment salinity and chlorophyll collectively drive surface SOC, explaining 93% of its variance. Sediment water content and the percentage of fine sediment have a negative impact on sediment CO2 flux but a positive effect on surface SOC content, while sediment chlorophyll is a positive driver of both. Surface SOC was significantly higher in Avicennia marina (2994±186 g m-2, mean+ SD) than in Rhizophora stylosa (2383± 209 g m-2). SOC was significantly higher in winter (2771±192 g m-2) than in summer (2599±211 g m-2). SOC significantly increased from creek-side (865±89 g m-2) through mid (3298±137 g m-2) to landward (3933±138g m-2) locations. Sediment salinity was a positive driver of SOC. Sediment CO2 flux without the influence of biogenic structures (crab burrows, aerial roots) averaged 15.4 mmol m-2 d-1 in A. marina stands under dark conditions, lower than the global average dark flux (61 mmol m-2 d-1) for mangroves.
CO2 flux is a critical component of the global C budget. While CO2 flux has been increasingly studied in mangroves, few studies partition components contributing to the flux. Partitioning CO2 flux sources helps constrain C budgets. We developed the combined 13C stable isotope labelling and closed chamber technique. The technique was used to partition CO2 efflux from the seedlings of mangrove Avicennia marina in laboratory microcosms, with a focus on sediment CO2 efflux. The result showed that (1) canopy was the chief component of ecosystem CO2 efflux, (2) the degradation of sediment organic matter was the major component of sediment CO2 efflux, followed by root respiration and litter decomposition via isotope mixing models. There was a significant relationship between δ13C values of CO2 released at the sediment-air interface and both root respiration and sediment organic matter decomposition. The findings provide the relative contribution of different components to ecosystem and sediment CO2 efflux, and thus can partition the sources of ecosystem respiration and sediment C mineralization in mangroves.
My thesis demonstrates that saltmarshes play a disproportionately important role in sediment C accumulation (244.7 g C m-2 yr-1) although their global area extent is declining, and saltmarsh CAR varies with latitude, tidal range, elevation and biogeographic regions. Dead root production contributes a significant proportion to sediment C in both mangroves and saltmarsh, and the updated global estimate of root C decomposition (8 Tg C yr-1) in mangroves reflects an underestimate in the reported value (5 Tg C yr-1). In a sub-tropical mangrove forest, SOC content and CO2 flux are influenced by sediment physio-chemical properties, and/or species, light conditions. Sediment water content and the percentage of fine sediment have contrasting effect on both but sediment chlorophyll is a positive driver of both, and these factors may be highlighted in ‘blue C’ management of this mangrove. In establishing mangroves (Avicennia marina), the result of a laboratory microcosm experiment shows that canopy was the major source of ecosystem CO2 efflux. The decomposition of roots contributes more to sediment CO2 efflux in comparison with sediment organic matter, which is in contrast to the pattern in mature mangroves.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
5
Theriault, Holly Jean. "Stratigraphic Analysis and Transgression Rates of Maine's Coastal Wetlands Due to Rising Sea Level". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/TheriaultHJ2008.pdf.
Pełny tekst źródła
6
Seilheimer, Titus Spear Chow-Fraser Patricia. "Development and use of fish-based indicators of wetland quality for Great Lakes coastal wetlands". *McMaster only, 2006.
Znajdź pełny tekst źródła
7
Powell, Paula Angele. "The effects of hydrology and nutrient inputs at South Milton Ley on the ecology of the common reed Phragmites australis (Cav. Trin. ex Steudal)". Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/2061.
Pełny tekst źródłaStreszczenie:
South Milton Ley is a small coastal wetland in Southern England. A sand-bar forms periodically at its seaward end and separates fresh water from the sea. The common reed Phragmites australis dominates the wetland and when a sand bar is present a shallow freshwater lake forms. Monthly water budgets were prepared for the years 1994, 1995 and 1996 and intermittent flooding of the Ley was also monitored. This information was used to calculate a range of residence times (between one hour and eleven days) and the characteristics of various flow regimes when the sandbar, which dams the Ley, is open or closed. Reed growth and the lake's ecology are potentially influenced by effluent from a sewage treatment works (STW) that discharges into the wetland. Water chemistry and hydrology of the wetland have been studied alongside experiments to investigate any effects of nutrient enrichment from the STW on reed growth. Inflowing and outflowing waters were analysed in order to determine concentrations of total oxidised nitrogen (TON), total dissolved nitrogen (TDN), soluble reactive phosphorus (SRP), total dissolved phosphorus (TDP) and potassium (K). Over the study period the annual load of SRP to the Ley increased from 3.65 gmˉ² aˉ¹ in 1992 to 8.1 gmˉ² aˉ¹ in 1996. TON load rose from 69.35 g mˉ² aˉ¹ in 1992 to 104.8 g mˉ² aˉ¹ in 1996. K fell from 97.3 g mˉ² aˉ¹ in 1994 to 96.4 g mˉ² aˉ¹ in 1996. The STW uses a Reedbed Treatment System (RBTS) to 'polish' its final effluent. The efficiency o f the RBTS was studied and during 1996 the efficiency rate for T ON was 20.9% and for SRP was 9.3%. Measurements of height, diameter, numbers of internodes, density and biomass of reeds collected from South Milton Ley were undertaken during August 1994 and 1995. Results of analyses for 1994 indicate that reeds were thinner and possessed fewer seedheads than those of 1995 but that density was greater. Reed fieldwork during 1994 found that height, diameter, numbers of internodes, biomass and number of seedheads were greater below the STW than above. During 1995 only seedhead production was greater below the outlet. The wettest area of the Ley contained reeds with greatest height and diameter. The driest area produced a higher density of reed growth. Laboratory experiments suggested that low N:K ratios and high P:K produced taller plants. Data from reed fieldwork together with results from hydrology and water chemistry studies were used in a statistical analysis in order to determine which, if any of these factors caused changes in reed growth. A conclusive link between water chemistry, hydrology and plant variables was not found. Correlation analysis for 1994 indicated that high concentrations of SRP and TON could produce thin reeds with low biomass. Analysis for 1995 suggested that elevated K values could produce a high density of short reeds. Water depth was found to have a significant effect (P < 0.001) on diameter. The key factors for reed decline (high water levels from spring to winter which can inhibit reed regeneration and increase residence times, increasing nutrient loads and changes in the ratio of N:P:K which could alter reed growth) are all present. At its present loading the Ley is nutrient rich and does not appear to be buffering wetland waters. After data analysis and fieldwork was completed a bloom of Oscillatoria sp.occurred at the seaward end of the Ley during August 1999. This, the first know occurrence of a bloom may be an indication that changes in the ecosystem of South Milton Ley are occurring. For the future, a programme of nutrient reduction, hydrological management and growing knowledge of wetland processes may prevent adverse changes.
8
Wilson, Benjamin J. "Drivers and Mechanisms of Peat Collapse in Coastal Wetlands". FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3718.
Pełny tekst źródłaStreszczenie:
Coastal wetlands store immense amounts of carbon (C) in vegetation and sediments, but this store of C is under threat from climate change. Accelerated sea level rise (SLR), which leads to saltwater intrusion, and more frequent periods of droughts will both impact biogeochemical cycling in wetlands. Coastal peat marshes are especially susceptible to saltwater intrusion and changes in water depth, but little is known about how exposure to salinity affects organic matter accumulation and peat stability. I investigated freshwater and brackish marsh responses to elevated salinity, greater inundation, drought, and increased nutrient loading. Elevated salinity pulses in a brackish marsh increased CO2 release from the marsh but only during dry-down. Elevated salinity increased root mortality at both a freshwater and brackish marsh. Under continuously elevated salinity in mesocosms, net ecosystem productivity (NEP) was unaffected by elevated salinity in a freshwater marsh exposed to brackish conditions (0 à 8 ppt), but NEP significantly increased with P enrichment. Elevated salinity led to a higher turnover of live to dead roots, resulting in a ~2-cm loss in soil elevation within 1 year of exposure to elevated salinity. When exposing a brackish marsh to more saline conditions (10 à 20 ppt), NEP, aboveground biomass production, and root growth all significantly decreased with elevated salinity, shifting the marsh from a net C sink to a net C source to the atmosphere. Elevated salinity (10 à 20 ppt) did not increase soil elevation loss, which was already occurring under brackish conditions, but when coupled with a drought event, elevation loss doubled. My findings suggest these hypotheses for the drivers and mechanisms of peat collapse. When freshwater marshes are first exposed to elevated salinity, soil structure and integrity are negatively affected through loss of live roots within the soil profile, leaving the peat vulnerable to collapse even though aboveground productivity and NEP may be unaffected. Subsequent dry-down events where water falls below the soil surface further accelerate peat collapse. Although saltwater intrusion into freshwater wetlands may initially stimulate primary productivity through a P subsidy, the impact of elevated salinity on root and soil structure has a greater deleterious effect and may ultimately be the factors that lead to the collapse of these marshes.
9
Regan, Matthew. "Plant community response to wetland enhancement techniques in coastal wetlands of the upper St. Lawrence River". Thesis, State University of New York Col. of Environmental Science & Forestry, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10254553.
Pełny tekst źródłaStreszczenie:
Stabilized water levels of the upper St. Lawrence River have reduced plant diversity and allowed competitively dominant taxa such as Typha x glauca and Typha angustifolia to displace productive sedge meadow habitat. This research studied the effects of two wetland enhancement techniques using habitat heterogeneity and manipulating hydrology. Dredge spoils from pothole excavations in Typha marshes were reconfigured to create habitat mounds. These habitat mounds created from an exposed seed bank had less Typha spp. and were more diverse than the surrounding remnant Typha marshes. Sedge meadow vegetation did not successfully colonize these habitat mounds. Water levels at two wetlands were raised above the water levels of the upper St. Lawrence River. Raising water levels increased floating leaf aquatic vegetation but did not decrease Typha spp. Alternative enhancement methods may be necessary to control Typha spp. while restoring sedge meadows.
10
Wilton, Kylee Margaret, i res cand@acu edu au. "Coastal Wetland Habitat Dynamics in Selected New South Wales Estuaries". Australian Catholic University. School of Arts and Sciences, 2002. http://dlibrary.acu.edu.au/digitaltheses/public/adt-acuvp29.29082005.
Pełny tekst źródłaStreszczenie:
Intertidal wetland habitats in southeastern Australia have changed significantly during the past sixty years. Mangrove habitats have expanded both seawards and landwards, the latter being at the expense of saltmarsh habitats. This relatively common phenomenon is generally suggested to be an outcome of sea-level rise. Several factors potentially responsible for this change are examined, including changes in mean sealevel during the past 50 to 100 years, changes in climate, population growth, catchment landuse, and estuary type. A protocol for mapping estuarine habitats was developed and implemented, incorporating the application of geographic information systems. Spatial and temporal coastal wetland habitat changes at nine sites along the New South Wales coast are illustrated. These habitat dynamics were shown to not correlate between sites. The results demonstrate that sea-level rise in this region cannot solely account for the extent of change during the past sixty years. With the exception of one site (Careel Bay), there have been no correlations between contemporary mean sea-level rise and mangrove incursion of the saltmarsh habitats at the study sites, or with rainfall patterns, at the scale of observation in this study, which was largely decadal. The only correlations determined during this study have been between population growth and coastal wetland habitat dynamics in some sites. In spite of saltmarsh habitat loss being a regional phenomenon, local factors appear to have a profound bearing on the rates of change. Neither contemporary mean sea-level rise, rainfall patterns, estuary type, catchment landuse, catchment natural cover nor population pressure can account solely for the patterns in the spatial and temporal dynamics of the coastal wetlands of New South Wales. It seems apparent that regional factors create preconditions favourable for mangrove incursion, but that localised conditions have been responsible for the extent of these incursions from site to site. That is, despite higher sea-level and greater rainfall, the extent of change has been determined by the unique characteristics of each site. The results have important implications for current estuary management practices in the state of New South Wales. The lack of spatial and temporal trends in coastal wetland habitat dynamics point to the need for management to be conducted on a localised, rather than regional scale. Additionally, anthropogenic influences must be carefully managed, since the extent of mangrove habitat expansion into saltmarsh areas is unlikely to be a natural occurrence.
11
Fruchter, Jesse. "DO LARGE, INFREQUENT DISTURBANCES RELEASE ESTUARINE WETLANDS FROM COASTAL SQUEEZING?" OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/923.
Pełny tekst źródłaStreszczenie:
As disturbance frequencies, intensities, and types have changed and continue to change in response to changing climate and land-use patterns, coastal communities undergo shifts in both species composition and dominant vegetation type. Over the past 100 years, fire suppression throughout the Northern Gulf of Mexico coast has resulted in shifts towards woody species dominance at the expense of marsh cover. Over the next 100 years, sea levels will rise and tropical storm activity is projected to increase; resultant changes in salinity could reduce cover of salt-intolerant fresh marsh species. Together, the effects of fire suppression upslope and rising salinities downslope could "squeeze" fresh marsh species, reducing cover and potentially threatening persistence. To mitigate the effects of fire suppression, the use of prescribed fire as a management tool to mimic historic conditions is becoming increasingly widespread and will likely gain further popularity during the 21st century. Ecological shifts that will result from changing disturbance regimes are unknown. It was hypothesized that two recent hurricanes, Ivan and Katrina in 2004 and 2005, respectively, and a prescribed fire, in 2010, differentially affected species along the estuarine gradient and drove overall shifts away from woody dominance. Overall community composition did not change significantly in the intermediate and fresh marsh zones. However, significant changes occurred in the salt and brackish marshes and in the woody-dominated fresh marsh-scrub ecotone zones. Relative to 2004, woody species abundance decreased significantly in all zones in 2006, following Hurricanes Ivan and Katrina, and 2012, following the hurricanes and fire, though woody species regeneration in the marsh-scrub ecotone had begun to occur by 2012. It is hypothesized that interacting changes in fire and tropical storm regimes could release upslope areas from coastal squeezing.
12
Blount, Keyyana. "Land Use Effects on Carbon Cycling in Oregon Coastal Wetlands". Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23152.
Pełny tekst źródłaStreszczenie:
Pacific Northwest coastal wetland extent has been significantly reduced due to development. To understand the effects of land use change on carbon cycling in coastal wetlands, we compared soil carbon dynamics in restored, disturbed (by diking or draining), and reference wetlands in both freshwater and saline conditions in Coos Bay, Oregon. We quantified soil carbon pools, measured in situ fluxes of methane (CH4) and carbon dioxide (CO2), and estimated sediment deposition and carbon sequestration rates. We found that land use change influences carbon cycling and storage in coastal wetlands. The disturbed marshes have likely lost all their organic material after draining or diking, except for a shallow A horizon. The restored marsh in situ CH4 and CO2 fluxes were intermediate between the disturbed and reference marshes. Generally, restored marshes showed a partial return of carbon storage functions, or an indication that reference level functions may be achieved over time.
13
Matavire, Melisa M. "Impacts of sugarcane farming on coastal wetlands of the north coast of Zululand, Kwadukuza, South Africa". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97121.
Pełny tekst źródłaStreszczenie:
Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Wetlands are key to providing important ecosystem goods and services yet they are under threat from a number of anthropogenic activities. In particular, in this study area, agriculture in the form of sugarcane farming is a threat to wetlands as sugarcane is reliant on a good water supply. The impacts of sugarcane farming emanates from the fact that sugarcane is a mono crop that requires wetland resources and uses a lot of pesticides and fertilisers. Despite the assumed contribution of sugarcane farming to wetland loss and degradation, few studies have quantitatively assessed the spatio-temporal changes in wetland extent as well as changes in water quality because of this activity. This study assesses the impacts of sugarcane farming on wetland extent and water quality in two coastal wetlands of KwaDukuza, North coast of Zululand, South Africa. Specifically this study sought to (i) assess the impacts of sugarcane farming on the spatial extent of wetlands between 1959 and 2012, (ii) determine if sugarcane farming negatively affect water quality within the wetlands and (iii) evaluate the perceptions of local farmers regarding impacts of sugarcane farming on wetlands. Results of the study indicated an increase in the extent of Zinkwazi sugarcane fields from 62.3% to 67% between 1959 and 1989 and Nonoti sugarcane fields’ extent increased from 50.5 % to 56.4% between 1959 and 2000. The last decade from the year 2000 showed gradual decrease in the area of wetland farmed by sugarcane due to the global sugar price remaining static while the cost of farming inputs increased and due to conversion of some farms to urban developments. Unfortunately, this has not lead to an increase in wetland area as the waterfront type developments, as well as a formal settlement have replace the sugarcane in the wetlands. Water was analysed for nitrogen (N), phosphorus (P) and potassium (K) and results for both Zinkwazi and Nonoti indicated an increasing trend of N and P from upstream to the middle region of the rivers and a decreasing trend of the N and P from the middle region to downstream. Sugarcane farming does not take place below the middle region and so does not provide fresh sources of these nutrients. The downstream area where the N and P decrease also coincides with the area of the river under tidal influence such that the N and P are being diluted by the incoming tidal seawater. K showed an increasing trend from upstream to downstream and its values were higher than N and P. Concentrations of N and P above the South African water quality guidelines for aquatic ecosystem were recorded in the middle region. Furthermore, farmers’ perceived wetlands to have been transformed to agricultural land and related these changes to their sugarcane farming activities. It can thus, be concluded that sugarcane farming has resulted in wetland loss as well as deterioration of water quality within the Zinkwazi and Nonoti wetlands in KwaDukuza. In that regard, there isneed to engage farmers in wetland management programs in order to reduce the negative environmental impacts associated with sugarcane farming in wetlands.
AFRIKAANSE OPSOMMING: Vleilande is die sleutel tot die verskaffing van ‘n belangrike ekosisteem dienste, maar hulle is onder ‘n bedreiging deur 'n aantal menslike aktiwiteite. In besonder in hierdie studie area, is Argriculture in die vorm van suikerriet boerdery is bedraging vir vleilande, en suikerriet is afhanklik van 'n goeie watervoorraad. Ten spyte van die veronderstelde bydraes van suikerriet boerdery, is die vleiland aan die agteruitgang, 'n Paar studies het kwantitatief die tydruimtelike veranderinge in die vleiland, sowel as veranderinge in die gehalte van water as gevolg van hierdie aktiwiteit waargeneem. Spesifiek is hierdie studie gepoog om (i) te bepaal wat die impak van suikerriet boerdery op die ruimtelike omvang van die vleiland tussen 1959 en 2012 is, (ii) bepaal of suikerriet boerdery negatief beïnvloed is deur die gehalte van water in die vleilande en (iii) die persepsies van plaaslike boere rakende die evalueering en impak van suikerriet boerdery op die vleilande. Resultate van die studie het aangedui 'n toename in die omvang van Zinkwazi suikerriet velde van 62,3% tot 67% tussen 1959 en 1989, en die Nonoti suikerriet velde toegeneem het met 50,5% tot 56,4% tussen 1959 en 2000. Die laaste dekade van die jaar 2000 het geleidelike afname in die area van die vleilande getoon, omdat suikerriet as gevolg van die globale suiker prys die koste van boerdery-insette verhoog het, en dit het gelei tot die omskakeling van 'n paar plase na stedelike ontwikkelings. Ongelukkig het dit nie gelei tot 'n toename in die vleiland gebiede nie, met die gevolg die waterfront tipe ontwikkelings, asook 'n formele nedersetting, vervang die suikerriet in die vleilande. Water is ontleed vir N, P en K en resultate vir beide Zinkwazi en Nonoti, het aangedui 'n toenemende tendens van stikstof en Fosfor. Dit gaan stroomop na die middel-streek van die riviere en 'n dalende neiging van die N en P uit die middel streek stroomaf. Suikerriet boerdery vind nie plaas onder die middel streek nie, en so is daar nie vars bronne, wat van hierdie voedingstowwe verskaf nie. Die stroomaf gebied waar die N en P ‘n afname het, val ook saam met die gebied van die rivier onder die gety , en dit beinvloed sodanig dat die N en P se water verdun word deur die inkomende gety se seewater. K het 'n toenemende neiging van stroomop en stroomaf en sy waardes is hoër as van die N en P. Konsentrasies van N en P bo die Suid-Afrikaanse water standaard riglyne is in die middel streek aangeteken. Verder, beskou boere dat die vleilande behoort te verander om die landbougrond en verwante veranderinge aan hul suikerriet boerdery en aktiwiteite. Ons kan dus aflei dat suikerriet boerdery het gelei tot die vleiland se verlies asook die verandering in die watergehalte in die Zinkwazi en die Nonoti vleilande in KwaDukuza. In dié verband is dit nodig dat die boere in die vleiland by programme betrek word ten einde die negatiewe omgewingsimpakte wat met suikerriet boerdery gepaard gaan in vleilande te verminder.
14
Anorov, Julie Margaret, i n/a. "Integrated Study of Coastal Wetland Characteristics and Geomorphic Processes in a South East Queensland Catchment". Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060223.153104.
Pełny tekst źródłaStreszczenie:
Coastal wetlands are dynamic ecosystems that are highly susceptible to change due to natural and human factors. The study area, located within the Native Dog Creek sub-catchment of the Logan River - which drains into Moreton Bay, south east Queensland - holds a detailed history of environmental change spanning most of the Holocene epoch. This history is preserved in the estuarine sedimentary record and is a valuable indicator of natural environmental change. More recently, human-induced changes within the study area have been superimposed on the natural process of environmental change. In order to develop a conceptual bio-geomorphic model of the coastal wetlands of Native Dog Creek, this thesis examined - on an integrated catchment basis - the evolution and connectivity of four coastal wetland community types (Melaleuca, Casuarina, saltmarsh and mangroves). The research consisted of four discrete studies within the study area: a geomorphic investigation that provided a framework for understanding how the wetlands evolved during the Holocene epoch; an acid sulfate soil (ASS) study that surveyed the distribution and concentration of sulfides; a palynological study that examined the natural directions of ecosystem change; and an investigation of the impact of specific human activities on these ecosystems. Detailed stratigraphic modelling found that the Logan River system (and its Native Dog Creek sub-catchment) has evolved from an infilling estuary since the peak of the Holocene transgression 6500 years before present. Recognition of the major controls that influenced geomorphic coastal development during the Holocene, provided important insights into the distribution and genesis of estuarine pyritic sediments which strongly influence the soils within the study area. In general, the estuarine central basin and fluvial delta sediments posed the greatest risk to the environment from acidification if disturbed. The major focus of the ASS study was to survey the distribution of ASS and to identify other areas most vulnerable to acidification. A predictive approach that combined chemical and stratigraphic analysis was used. Results showed that these areas are intrinsically related to their environment of deposition. The study found, for example, that the alternation of excessively wet and dry conditions - combined with high organic carbon levels and variations in microtopography - provided ideal conditions for the re-formation of pyrite in the stream channel within the Melaleuca wetlands. The palaeo-environmental study reconstructed the evolution of Holocene coastal wetland vegetation during the marine transgression and subsequent shoreline progradation. Pollen records from the four representative wetland communities (previously mentioned) were examined. The results found the mid-late Holocene vegetation history was controlled by the development of geomorphic features that have affected freshwater input, drainage and salinity. In response to the progradation of the shoreline after sea level stabilised, changes in fossil pollen from mangroves and saltmarsh taxa during the early-mid Holocene, to freshwater taxa during the late Holocene, are estimated to have taken 800 years. Thus, pollen analysis when used in combination with stratigraphic modelling, provided an important point of reference for rates of natural ecological change in response to evolutionary changes to the physical environment. The wetlands within the study area have suffered varying degrees of disturbance since European settlement in the 1820s. The most significant changes occurred during early European settlement, when vast areas of coastal lowlands were cleared for timber, sheep and cattle grazing and for agricultural purposes. A second period of change occurred from 1989 to 1995, when the Melaleuca community suffered dieback in response to hydrological modifications to Native Dog Creek for the development of a golf course. Results indicate that human-induced changes over the past 170 years have occurred at a rate far beyond the ability of the natural ecosystem to adapt or move to a more ecologically sustainable state, at least in the short-term. Hence the current environment is experiencing degradation through both decline in health and loss of indigenous species. The development of a conceptual bio-geomorphic model was based on the integration of results from all four studies, in an effort to provide a holistic understanding of the coastal wetland environment and of the impact of human-induced changes upon that environment. If these vulnerable ecosystems are to be maintained, successful and sustainable coastal management strategies must rely on a sound scientific understanding of the response of a coastal ecosystem to both human and environmental changes.
15
Anorov, Julie Margaret. "Integrated Study of Coastal Wetland Characteristics and Geomorphic Processes in a South East Queensland Catchment". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/365955.
Pełny tekst źródłaStreszczenie:
change due to natural and human factors. The study area, located within the Native Dog Creek sub-catchment of the Logan River - which drains into Moreton Bay, south east Queensland - holds a detailed history of environmental change spanning most of the Holocene epoch. This history is preserved in the estuarine sedimentary record and is a valuable indicator of natural environmental change. More recently, human-induced changes within the study area have been superimposed on the natural process of environmental change. In order to develop a conceptual bio-geomorphic model of the coastal wetlands of Native Dog Creek, this thesis examined - on an integrated catchment basis - the evolution and connectivity of four coastal wetland community types (Melaleuca, Casuarina, saltmarsh and mangroves). The research consisted of four discrete studies within the study area: a geomorphic investigation that provided a framework for understanding how the wetlands evolved during the Holocene epoch; an acid sulfate soil (ASS) study that surveyed the distribution and concentration of sulfides; a palynological study that examined the natural directions of ecosystem change; and an investigation of the impact of specific human activities on these ecosystems. Detailed stratigraphic modelling found that the Logan River system (and its Native Dog Creek sub-catchment) has evolved from an infilling estuary since the peak of the Holocene transgression 6500 years before present. Recognition of the major controls that influenced geomorphic coastal development during the Holocene, provided important insights into the distribution and genesis of estuarine pyritic sediments which strongly influence the soils within the study area. In general, the estuarine central basin and fluvial delta sediments posed the greatest risk to the environment from acidification if disturbed. The major focus of the ASS study was to survey the distribution of ASS and to identify other areas most vulnerable to acidification. A predictive approach that combined chemical and stratigraphic analysis was used. Results showed that these areas are intrinsically related to their environment of deposition. The study found, for example, that the alternation of excessively wet and dry conditions - combined with high organic carbon levels and variations in microtopography - provided ideal conditions for the re-formation of pyrite in the stream channel within the Melaleuca wetlands. The palaeo-environmental study reconstructed the evolution of Holocene coastal wetland vegetation during the marine transgression and subsequent shoreline progradation. Pollen records from the four representative wetland communities (previously mentioned) were examined. The results found the mid-late Holocene vegetation history was controlled by the development of geomorphic features that have affected freshwater input, drainage and salinity. In response to the progradation of the shoreline after sea level stabilised, changes in fossil pollen from mangroves and saltmarsh taxa during the early-mid Holocene, to freshwater taxa during the late Holocene, are estimated to have taken 800 years. Thus, pollen analysis when used in combination with stratigraphic modelling, provided an important point of reference for rates of natural ecological change in response to evolutionary changes to the physical environment. The wetlands within the study area have suffered varying degrees of disturbance since European settlement in the 1820s. The most significant changes occurred during early European settlement, when vast areas of coastal lowlands were cleared for timber, sheep and cattle grazing and for agricultural purposes. A second period of change occurred from 1989 to 1995, when the Melaleuca community suffered dieback in response to hydrological modifications to Native Dog Creek for the development of a golf course. Results indicate that human-induced changes over the past 170 years have occurred at a rate far beyond the ability of the natural ecosystem to adapt or move to a more ecologically sustainable state, at least in the short-term. Hence the current environment is experiencing degradation through both decline in health and loss of indigenous species. The development of a conceptual bio-geomorphic model was based on the integration of results from all four studies, in an effort to provide a holistic understanding of the coastal wetland environment and of the impact of human-induced changes upon that environment. If these vulnerable ecosystems are to be maintained, successful and sustainable coastal management strategies must rely on a sound scientific understanding of the response of a coastal ecosystem to both human and environmental changes.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
16
Ogorek, Jacob. "Sediment methylmercury concentrations and production rates in coastal wetlands of Chequamegon Bay (WI), Lake Superior /". Connect to online version, 2009. http://minds.wisconsin.edu/handle/1793/45132.
Pełny tekst źródła
17
McNair, Sheila A. Chow-Fraser Patricia. "The use of primary producers for assessing and monitoring aquatic habitat quality in Great Lakes coastal wetlands". *McMaster only, 2006.
Znajdź pełny tekst źródła
18
Teasdale, Phillip Angus. "The late holocene evolution of coastal wetlands in Argyll, Western Scotland". Thesis, Brunel University, 2005. http://bura.brunel.ac.uk/handle/2438/5574.
Pełny tekst źródłaStreszczenie:
A detailed geochronological and geochemical study has been undertaken on selected sediment cores from four lowland coastal marsh environments in Argyll, Western Scotland. This region of northern Britain has experienced differential crustal uplift and relative sea-level changes throughout the Holocene in response to glacio-isostatic adjustment. The complex interplay between land movements and relative sea-level continues to influence the morphological development of the Scottish coast. The study of lowland inter-tidal sedimentary environments from this region provides an opportunity to investigate the linkages between current estimated crustal movements, regional relative sea-level rise and the evolution of contemporary coastal saltmarshes derived from the record of historical sedimentation. The four sites are located across a ca. 70 km transect extending from the head of Loch Scridain (western Isle of Mull), across the Firth of Lorne to the head of Loch Etive, (mainland Argyll). Vertical activity distributions of the natural radionuclide 21OPb and anthropogenic isotopes (137Cs and 243Am) have been measured and are used to assess the depositional history of marsh sediment accumulation recorded in the four marsh cores. Down-core activity profiles of radionuclides are only reliable as a means of modelling recent marsh evolution provided no early-diagenetic (redox) reactions have compromised the historical depositional record within the marsh sediments. Solid-phase major and trace element down-core geochemical distributions provide a means of assessing the extent to which post-depositional (redox) reactions may have influenced the reliability of the radiometric dating methods. Marsh sediment geochemistry also serves as a useful proxy for identifying compositional variability over the period of marsh development investigated. Dating of the Argyll saltmarsh cores indicates that over the period corresponding to mature marsh conditions rates of sedimentation vary significantly across the study area. At Loch Scridain an average rate of 1.1 mm yr-1 corresponding to an historical period of ca. 130 years is recorded. Comparison with estimated rates of regional sea-level rise suggest an established asymptotic relationship between marsh accretion and coastal forcing, implying historical crustal stability at this site. At sites within the Firth of Lome (Loch Don and Loch Creran) average rates of 2.5 and 3.3 mm yr-1 are recorded for the ca. 70 year period to 1995 with a figure of 2.2 mm yr-1 recorded in the marsh core from the head of Loch Etive. These values are well in excess of estimated relative sea-level rise during the twentieth century suggesting that these marshes may not yet have reached full equilibrium with sea-level. Microfossil analysis of the Loch Etive core helps to identify a more complex depositional history with an underlying trend of marine transgression for the ca. 110 year period of marsh development recorded in these sediments. Over the most recent period of marsh development (ca. 5 years) a significant increase in the rate of marsh sedimentation at all sites is recorded. This signifies the response of these marshes to a very recent increase in the rate of relative sea-level rise across the region. Comparison with available storm frequency data indicates that the evolution of these marsh environments have not been subject to the influence of significant storm activity over the last in the late Twetieth century. The findings suggest that the more clastic sedimentary composition of the Argyll marshes results in these inter-tidal areas being extremely sensitive to changes in coastal forcing (sea-level rise). The implications of recent relative sea-level rise, current vertical crustal movements and future coastal management are discussed.
19
Cummings, Angela R. "An Analysis of Palustrine Mitigation Wetlands in the Virginia Coastal Plain". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/78141.
Pełny tekst źródłaStreszczenie:
In recent years, the success of wetland mitigation projects and their ability to function as natural systems has been questioned. This study was conducted (i) to characterize and examine differences between mitigation and natural wetlands, (ii) to examine differences in soil morphology along a wetness gradient in mitigation and natural wetlands, and (iii) to observe changes in mitigation wetlands with time. Site characteristics, including soil properties, hydrology, and vegetation, were analyzed for three mitigation-reference wetland pairs located in the Virginia Coastal Plain. Hydrologic regimes of mitigation areas, when compared to reference areas, generally showed larger differentials between seasonal high and low watertables. Mitigation areas, dominated by herbaceous vegetation, tended to be lower in C and N levels and higher in soil pH, and much higher in bulk density than the mature forested reference wetland. Initially low levels of C and N did not increase significantly over the five-year study period. Soils in the mitigation area were more uniform and considerably less differentiated when compared to those of the reference area. Testing for Fe(II) with alpha-alpha, dipyridyl dye solution produced mixed results, obtaining both positive and negative reactions to saturated samples. Oxidized rhizospheres, associated with active root channels in surface horizons, formed in less than ten years under the current hydrologic conditions. These features were more abundant and more prominent in areas saturated at or above the surface for longer periods of time. Overall, site differences between mitigation and reference areas are mainly due to construction practices and a lack of organic matter accumulation. Better design methods should incorporate the addition of organic amendments, with attempts to minimize soil compaction.Master of Science
20
Grieger, Rebekah. "Resilience of Coastal Freshwater Wetland Vegetation to Climate Change". Thesis, Griffith University, 2021. http://hdl.handle.net/10072/410470.
Pełny tekst źródłaStreszczenie:
Coastal wetlands are globally important ecosystems, valued for their provision of habitat, storm mitigation, water quality improvement, and carbon sequestration. Coastal wetlands are also one of the ecosystems most likely to be impacted by projected changes in climate, particularly changes associated with sea level rise, altered rainfall patterns, and changes to storm patterns and severity. Coastal freshwater wetlands (CFWs) are amongst the most understudied group of coastal wetlands and are characterised by freshwater dominated hydrology but can also experience periods of salinity associated with their proximity to the coast (i.e. as the result of storm surge and spring high tides). CFWs commonly occur as the most landward of coastal wetlands and many adjoin urban development, exposing them to anthropogenic impacts (nutrient enrichment, clearing, hydrology alteration). This position in the coastal landscape makes CFWs highly susceptible to salinity stress, particularly climate change induced sea level rise. Research investigating CFWs, their ecology, and responses to climate change threats, is greatly lacking, particularly for areas outside the United States of America (USA). This thesis investigates the resilience of CFWs to climate change and aims to address significant knowledge gaps by investigating: 1) the current knowledge of CFW responses to projected climate change globally; 2) the structure and composition of CFW vegetation in southeast Queensland and exploring drivers of vegetation patterns; 3) the role of soil seed banks in vegetation resilience for CFWs in southeast Queensland through contributions to vegetation dynamics; and 4) the regenerative potential and responses of CFW vegetation communities to altered hydrology and salinity regimes simulating sea level rise. To begin, I synthesised the current knowledge of CFW responses to projected changes in climate globally, through a systematic quantitative literature review, with the aim of identifying key knowledge gaps regarding geographic locations and research areas, with particular focus on four key aspects of climate change: sea level rise, altered rainfall, extreme events, increased temperature, and greenhouse gases. In Chapter 2, I reviewed published research on responses of CFWs in observational, experimental, and modelling studies within those four key aspects of climate change. This review identified that, despite the increasing research interest, knowledge of all aspects of climate change is lacking, particularly outside of the USA. Within the USA, while there is a significant body of research exploring the response of CFWs to impacts associated with rising sea levels, changes to rainfall patterns, and extreme events, the impacts of temperature and greenhouse gases remain unknown globally. Importantly, research investigating the response of CFWs to multiple climate drivers was identified as a significant knowledge gap.The research then focused on field and greenhouse studies of CFW vegetation communities in southeast Queensland, Australia to expand the knowledge of CFWs outside of the USA. Chapters 3 and 4 explored patterns in standing and soil seed bank vegetation assemblages and provides a baseline understanding of the structure and composition of these vegetation communities. In addition, I assessed local and regional environmental drivers (i.e. local hydrology, soil salinity, local land uses, projected sea level rise extent) of vegetation patterns and discussed potential changes to these drivers with climate change. To explore the effects of sea level rise on ground in CFWs, I conducted an in-situ hydrology and salinity manipulation experiment at an abandoned sugarcane farm which has a regenerating CFW vegetation community (Chapter 5). CFWs in southeast Queensland are important for their roles in nutrient cycling and habitat provision for endangered fauna species. My assessment of these vegetation communities (Chapter 3) also highlights that CFWs are home to a diverse vegetation assemblage including at least two flora species of national significance, flagging the biodiversity importance of these isolated wetland patches within a developed coastal landscape. Species composition was distinct between vegetation patches and a large proportion of variation between sites was associated with differences in local hydrology and salinity influence. The importance of hydrology and salinity as drivers of vegetation patterns suggests that climate change could dramatically impact the structure and composition of CFWs. The ability of CFWs to be maintained in the landscape under a changing climate is influenced by their regenerative capacity from soil seed banks or other propagule banks. In Chapter 4, I assessed the composition of CFW soil seed banks and explored potential drivers of vegetation patterns. Through this study, I again found that hydrology and salinity were strong drivers of patterns in soil seed bank composition, as well as, local land use which was associated with the proportion of exotic species. Similarity of soil seed banks to standing vegetation was low, suggesting that soil seed banks have a minimal role in maintaining standing vegetation communities in southeast Queensland CFWs. Rather, soil seed banks could provide a mechanism for vegetation change along four possible trajectories depending on the soil seed bank composition and abiotic conditions. Hydrology and salinity are important drivers of CFW vegetation composition identified in this thesis. In Chapter 5, I explored the impacts of altered hydrology and salinity regimes on CFW vegetation communities regenerating on abandoned agricultural land. Change in vegetation composition and structure was assessed in-situ at Yandina Creek Wetlands (YCW) where vegetation has naturally regenerated into communities typical of CFWs in southeast Queensland during 15 years since abandoment of sugarcane production. This regeneration potential is important given the projected constriction of CFWs between migrating seaward Changes were varied in each habitat surveyed, however, reductions in vegetation cover and species richness were observed over time in response to altered conditions in freshwater habitats. Conversely, vegetation cover increased in the saltmarsh, suggesting that this community is tolerant of the altered conditions and may expand within YCW. The changes observed at YCW suggest that widespread change is likely for many CFWs with increasing sea levels, but careful management could aid in maintaining these ecosystems in the coastal landscape. Overall, this thesis significantly furthers the understanding of CFWs and their vegetation patterns outside of the USA, and explores the future of these systems with climate change in southeast Queensland, Australia. The findings of this thesis highlight the importance of hydrology and salinity as drivers of vegetation patterns and indicates that dramatic and potentially rapid change in vegetation structure and composition will occur as a result of climate change. CFWs in southeast Queensland are important and highly variable vegetation communities, where loss of even single wetland patches could result in local species extirpation. It is unlikely that CFWs will remain in the landscape in their current state and continue to provide benefits from ecosystem services without significant management action. Even with such action, widespread loss or modification is likely and continued research is required to understand the full scope of climate change impacts.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
21
Charles, Sean Patrick. "Saltwater Intrusion and Vegetation Shifts Drive Changes in Carbon Storage in Coastal Wetlands". FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3791.
Pełny tekst źródłaStreszczenie:
Coastal wetlands protect coastlines through efficient storage of organic carbon (OC) that decreases wetland vulnerability to sea level rise (SLR). Accelerated SLR is driving saltwater intrusion and altering vegetation communities and biogeochemical conditions in coastal wetlands with uncertain implications. We quantified changes in OC stocks and fluxes driven by 1) saltwater and phosphorous intrusion on freshwater and brackish marshes, 2) vegetation along an experimental saltmarsh to mangrove gradient, 3) saltwater intrusion and vegetation change across a marsh to mangrove ecotone, and 4) vegetation change and mangrove forest development along a marsh to mangrove ecotone. Increasing salinity in freshwater marshes decreased root biomass and soil elevation within one year. In brackish marshes, increased salinity decreased root productivity and biomass and increased root breakdown rate (k), while added salinity did not increase elevation loss. In our experimental marsh-mangrove ecotone, mangrove vegetation promoted higher organic carbon (OC) storage by increasing above and belowground biomass and reducing organic matter k. However, mangroves also increased belowground k, and decreased allochthonous marine subsidies, indicating the potential for OC storage trade-offs. In the Southeast Everglades, we identified strong interior-coastal gradients in soil stoichiometry and mangrove cover. Interior freshwater soil conditions increased k, while total soil OC stocks decreased toward the coast indicating that saltwater intrusion is driving large scale soil OC loss. In the southeast Everglades, mangrove expansion increased root biomass and root productivity, but did not mitigate the overall loss of OC stocks toward the coast. Similarly, in the southwest Everglades, saltwater intrusion drove a decrease in soil OC. However, mangrove encroachment drove a rapid recovery and increased OC stocks. Mangrove encroachment doubled aboveground biomass within the last ten years, increased it 30 times in the last 30 years, and doubled belowground biomass after 20 years. Our research shows that 1) moderate saltwater intrusion without mangrove encroachment will lead to a loss in OC stocks and potentially lead to wetland elevation loss and submergence, 2) in the absence of a change in saltwater intrusion, mangrove expansion can enhance OC storage 3) mangrove expansion can mitigate OC loss during saltwater intrusion, but this pattern depends on mangrove recruitment and ecosystem productivity.
22
Chaun, Melissa Claire. "A Comparison of Three Wetland Evaluation Methods in their Assessment of Nontidal Wetlands in the Coastal Plain of Virginia". W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539617683.
Pełny tekst źródła
23
Shirley, Laura J. "Land-cover change in coastal wetlands along the northern Gulf of Mexico /". Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1251832991&sid=6&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Pełny tekst źródła
24
ZOBRIST, KURT DANIEL. "COASTAL HARMONY: BETWEEN MARINE ECOSYSTEMS AND COASTAL DEVELOPMENT". University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1082747560.
Pełny tekst źródła
25
Downs, Christine Marie. "Imaging Wetland Hydrogeophysics: Applications of Critical Zone Hydrogeophysics to Better Understand Hydrogeologic Conditions in Coastal and Inland Wetlands and Waters". Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7397.
Pełny tekst źródłaStreszczenie:
This dissertation consists of three projects utilizing electric and electromagnetic (EM) methods to better understand critical-zone hydrogeologic conditions in select Florida wetlands and waters.
First, a time-lapse electrical resistivity (ER) survey was conducted in section of mangrove forest on a barrier island in southeast Florida to image changes in pore-water salinity in the root zone. ER data show the most variability in the root zone over a 24-hour period, and, generally, the ground is more resistive during the day than overnight.
Second, a suite of three-dimensional forward models, based on varying lateral boundaries and conductivities typical of a coastal wetland, were run to simulate the EM response of a commerical electromagnetic induction instrument crossing over said boundaries. Normalized profiles show the transition is sharper in a hypersaline regime than one where freshwater and clay are present. Furthermore, enough variability exists in hypersaline regimes to justify collecting profile measurements in multiple coil configurations to constrain the nature of a lateral boundary.
Also, under certain circumstances, there are kinks in the EMI response even across abrupt boundaries due to concentrated current density at a layer's edge.
Lastly, geophysical surveys were conducted at six wetlands in west-central Florida to characterize potential hydrostratigraphic units and compare/contrast them to the current conceptual model for cypress dome wetlands. ER was used to image the geometry of the top of limestone; ground penetrating radar (GPR) was used to image stratigraphy beneath and surrounding wetlands. These wetlands can be grouped into two models. Topographic highs surrounding wetlands are controlled by the undulating top of limestone at sites where the region is characterized by limestone ridges. In contrast, topographic highs are controlled by thick sand packages at sites regionally characterized by sand dunes over scoured limestone.
26
MacÃdo, JoemÃlia ConceiÃÃo AraÃjo. "Distribution of functional groups of aquatic plants in coastal wetlands of northeastern Brazil". Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14346.
Pełny tekst źródłaStreszczenie:
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoAs plantas aquÃticas situadas em lagoas costeiras apresentam traÃos funcionais selecionados por condiÃÃes abiÃticas e relacionados à histÃria de vida, que lhes permitiram a colonizaÃÃo e estabelecimento nesses ambientes. O presente trabalho testou as seguintes hipÃteses: (1) que as espÃcies possuem um padrÃo homogÃneo de traÃos funcionais, resultando na formaÃÃo de poucos grupos; (2) que as variÃveis limnolÃgicas e pedolÃgicas atuam como filtro que selecionam esses traÃos e interferem na distribuiÃÃo das populaÃÃes na lagoa. Desta forma os traÃos funcionais das espÃcies presentes numa lagoa costeira do nordeste brasileiro foram analisados por meio de uma amostragem por transectos. Amostras de sedimento foram retiradas e analisadas em laboratÃrio. Os parÃmetros limnolÃgicos foram aferidos em campo, assim como a profundidade da lÃmina dâÃgua e a distÃncia de ocorrÃncia das espÃcies em relaÃÃo à margem. Os dados biolÃgicos evidenciaram a formaÃÃo de dois grupos funcionais, corroborando a primeira hipÃtese. PorÃm, as variÃveis abiÃticas foram associadas à distribuiÃÃo de poucas populaÃÃes, refutando a segunda hipÃtese. Com isso concluÃmos que a comunidade de plantas aquÃticas analisada à formada por traÃos semelhantes e os efeitos abiÃticos nÃo sÃo determinantes para formaÃÃo destes grupos.
Aquatic plants located in coastal lagoons have functional traits selected by abiotic conditions and related to the history of life, which allowed them to colonization and establishment in these environments. The present study tested the following hypotheses: (1) that the species have a homogeneous pattern of functional traits, resulting in the formation of a few groups; (2) that the limnological variables and soil act as a filter to select those traits and interfere in the distribution of populations in the pond. Thus the functional traits of the species present in a coastal lagoon in northeastern Brazil were analyzed using a sampling transects. Sediment samples were taken and analyzed in the laboratory. The limnology parameters were measured in the field, as well as the depth of the water depth and the occurrence of species away from the margin. Biological data showed formation of two functional groups, supporting the first hypothesis. But the abiotic variables were associated with the distribution of a few people, refuting the latter. Thus we conclude that the community of aquatic plants analyzed is formed by similar traits and abiotic effects are not decisive for the formation of these groups.
27
Kapusinski, Douglas John. "Factors Affecting Invertebrate and Fish Communities in Coastal Wetlands of the Great Lakes". Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1353202400.
Pełny tekst źródła
28
Fu, Jing. "Environmental Impacts of Aquaculture Ponds on Coastal Wetlands in the Yellow River Estuary". Kyoto University, 2017. http://hdl.handle.net/2433/225949.
Pełny tekst źródła
29
Kemp, Annabeth S. "Freshwater cyanoprokaryota blooms in the Swan Coastal Plain wetlands: ecology, taxonomy and toxicology". Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/1477.
Pełny tekst źródłaStreszczenie:
Relatively little published information on cyanoprokaryote (blue-green algal) blooms in the freshwater wetlands in Western Australia is available. There has been little research on the urban lakes and rivers, examining the relationship between environmental conditions and toxin-producing blooms. In this project the ecology, morphology and toxicity of cyanoprokaryota blooms in 27 metropolitan lakes and sumplands, as well as three major rivers, from 2000 to 2003, on the Swan Coastal Plain (SCP) in the southwest of Western Australia were investigated.A total of 24 species were identified and described, of which nine species had not been previously documented in the area. This included the potentially toxic species Cylindrospermopsis raciborskii, Aphanizomenon ovalisporum and Anabaena bergii var. limnetica. An illustrated guide to the common bloom-forming species was generated using conventional taxonomic criteria.Microcystis flos-aquae and Microcystis aeruginosa were the dominant bloom-forming cyanoprokaryotes, widespread in their distribution. Anabaena circinalis, A. bergii var. limnetica and Anabaenopsis elenkinii were the common filamentous species. Anabaena circinalis was common to certain freshwater sites, while A. bergii var. limnetica and A. elenkinii occurred in salinity ranging from fresh (< 1ppt) to hyposaline (3-10 ppt). Sites with similar species assemblages were identified using two-way indicator species analysis and clustering analysis. From this, a distinct distribution pattern emerged, which was defined by the main genera observed in the lakes – Microcystis, Anabaena, Aphanizomenon and Anabaenopsis.The spatial and temporal distribution of the common bloom-forming cyanoprokaryote species was examined in conjunction with spring-summer physico-chemical data using principal component analysis. It was found that pH, water temperature and electrical conductivity/salinity accounted for variations among the lakes, with electrical conductivity the variable explaining the greatest variation. Lakes located on the coast, or further inland at the base of the Darling Scarp, were more hyposaline to saline, and the remaining lakes were fresh. Although the SCP lakes form consanguineous groups based on geochemistry and hydrology, no similarities among them were found in terms of water quality.The relationship between nitrogen (N) and phosphorus (P) concentrations (total and dissolved inorganic) and cyanoprokaryote community structure (N-fixing versus non-N-fixing species) was investigated in five selected lakes; Yangebup Lake, Bibra Lake, Blue Gum Lake, Tomato Lake and Emu Lake. The lakes ranged from mesotrophic to eutrophic and supported spring-summer blooms containing multiple species. Overall an inverse relationship between cyanoprokaryote abundance and total ambient nutrient concentrations at the time of the blooms was evident. No transition in dominance in the community was observed in Yangebup Lake, Emu Lake and Bibra Lake, as they were dominated by non-heterocytic species (M. aeruginosa and M. flos-aquae) throughout spring and summer. For Yangebup Lake and Bibra Lake, the abundance of non-heterocytic species decreased concomitantly with decreasing dissolved inorganic N. In contrast, heterocytic species (A. circinalis) dominated the spring community in Tomato Lake, and summer community in Blue Gum Lake, when N and P concentrations were at their highest.The presence of microcystins in Microcystis dominated blooms was examined using high performance chromatography. A total of 32 natural bloom samples, representing 13 lakes, were analysed for microcystin variants; -LR, -RR and -YR. Twenty-eight samples proved to be toxic with the highest total microcystin concentration from 1645 to 8428.6 µg L[superscript]-1, the lowest concentrations were less than 10 µg L[superscript]-1 with some below the detection limit. Microcystis aeruginosa and M. flos-aquae were associated with these microcystin-containing blooms, although M. flos-aquae appear to be less toxic. The presence of Nodularia spumigena in the Lake Yangebup was associated with high concentrations of nodularin (1664 µg L[superscript]-1).Employing enzyme-linked immunosorbent assay for microcystins and the brine shrimp (Artemia) bioassays allowed a greater number of lake samples to be analysed and provided a rapid assessment of toxicity. The three methods for cyanotoxin detection verified Yangebup Lake, Herdsman Lake, Hyde Park, Jackadder Lake and Emu Lake as highly toxic sites. Low toxicity was demonstrated in samples from Lake Goollelal, Lake Joondalup, Lake Claremont, Blue Gum Lake and North Lake. These results provided the first evidence of cyanotoxin producing blooms in urban lakes of the SCP.A comparative study on cyanoprokaryota blooms in Swan River estuary, upper Canning River and upper Serpentine River found that these sites, although hyposaline to saline, contained species that were common in the freshwater lakes. Sampling the river systems showed M. aeruginosa, M. flos-aquae, A. circinalis, A. elenkinii and Planktothrix planctonica to be cosmopolitan in distribution, present in SCP wetlands of varied salinity. Similarities between the upper Canning River and lakes in environmental conditions and species assemblage were demonstrated using multivariate analyses.Toxin analysis of bloom samples from the Swan River and upper Canning River revealed microcystin concentrations were less than that of the surrounding lakes (1.05-124.16 µg L[superscript]-1). Similarly, nodularin concentrations were higher in Yangebup Lake than the upper Serpentine River. However, the dominance of Anabaena in Canning River samples, and the highly toxic result from the Artemia bioassay suggests microcystin is not the predominant cyanotoxin in this wetland.This study has produced an overview of the distribution and morphology of cyanotoxin-producing cyanoprokaryotes in the SCP wetlands. The data presented provide the basis for further cyanoprokaryote research in Western Australia, in particular the molecular characterisation of bloom-forming toxic species.
30
Kemp, Annabeth S. "Freshwater cyanoprokaryota blooms in the Swan Coastal Plain wetlands: ecology, taxonomy and toxicology". Curtin University of Technology, Division of Science and Engineering, Department of Environmental Biology, 2009. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=129384.
Pełny tekst źródłaStreszczenie:
Relatively little published information on cyanoprokaryote (blue-green algal) blooms in the freshwater wetlands in Western Australia is available. There has been little research on the urban lakes and rivers, examining the relationship between environmental conditions and toxin-producing blooms. In this project the ecology, morphology and toxicity of cyanoprokaryota blooms in 27 metropolitan lakes and sumplands, as well as three major rivers, from 2000 to 2003, on the Swan Coastal Plain (SCP) in the southwest of Western Australia were investigated.A total of 24 species were identified and described, of which nine species had not been previously documented in the area. This included the potentially toxic species Cylindrospermopsis raciborskii, Aphanizomenon ovalisporum and Anabaena bergii var. limnetica. An illustrated guide to the common bloom-forming species was generated using conventional taxonomic criteria.
Microcystis flos-aquae and Microcystis aeruginosa were the dominant bloom-forming cyanoprokaryotes, widespread in their distribution. Anabaena circinalis, A. bergii var. limnetica and Anabaenopsis elenkinii were the common filamentous species. Anabaena circinalis was common to certain freshwater sites, while A. bergii var. limnetica and A. elenkinii occurred in salinity ranging from fresh (< 1ppt) to hyposaline (3-10 ppt). Sites with similar species assemblages were identified using two-way indicator species analysis and clustering analysis. From this, a distinct distribution pattern emerged, which was defined by the main genera observed in the lakes – Microcystis, Anabaena, Aphanizomenon and Anabaenopsis.
The spatial and temporal distribution of the common bloom-forming cyanoprokaryote species was examined in conjunction with spring-summer physico-chemical data using principal component analysis. It was found that pH, water temperature and electrical conductivity/salinity accounted for variations among the lakes, with electrical conductivity the variable explaining the greatest variation. Lakes located on the coast, or further inland at the base of the Darling Scarp, were more hyposaline to saline, and the remaining lakes were fresh. Although the SCP lakes form consanguineous groups based on geochemistry and hydrology, no similarities among them were found in terms of water quality.
The relationship between nitrogen (N) and phosphorus (P) concentrations (total and dissolved inorganic) and cyanoprokaryote community structure (N-fixing versus non-N-fixing species) was investigated in five selected lakes; Yangebup Lake, Bibra Lake, Blue Gum Lake, Tomato Lake and Emu Lake. The lakes ranged from mesotrophic to eutrophic and supported spring-summer blooms containing multiple species. Overall an inverse relationship between cyanoprokaryote abundance and total ambient nutrient concentrations at the time of the blooms was evident. No transition in dominance in the community was observed in Yangebup Lake, Emu Lake and Bibra Lake, as they were dominated by non-heterocytic species (M. aeruginosa and M. flos-aquae) throughout spring and summer. For Yangebup Lake and Bibra Lake, the abundance of non-heterocytic species decreased concomitantly with decreasing dissolved inorganic N. In contrast, heterocytic species (A. circinalis) dominated the spring community in Tomato Lake, and summer community in Blue Gum Lake, when N and P concentrations were at their highest.
The presence of microcystins in Microcystis dominated blooms was examined using high performance chromatography. A total of 32 natural bloom samples, representing 13 lakes, were analysed for microcystin variants; -LR, -RR and -YR. Twenty-eight samples proved to be toxic with the highest total microcystin concentration from 1645 to 8428.6 µg L[superscript]-1, the lowest concentrations were less than 10 µg L[superscript]-1 with some below the detection limit. Microcystis aeruginosa and M. flos-aquae were associated with these microcystin-containing blooms, although M. flos-aquae appear to be less toxic. The presence of Nodularia spumigena in the Lake Yangebup was associated with high concentrations of nodularin (1664 µg L[superscript]-1).
Employing enzyme-linked immunosorbent assay for microcystins and the brine shrimp (Artemia) bioassays allowed a greater number of lake samples to be analysed and provided a rapid assessment of toxicity. The three methods for cyanotoxin detection verified Yangebup Lake, Herdsman Lake, Hyde Park, Jackadder Lake and Emu Lake as highly toxic sites. Low toxicity was demonstrated in samples from Lake Goollelal, Lake Joondalup, Lake Claremont, Blue Gum Lake and North Lake. These results provided the first evidence of cyanotoxin producing blooms in urban lakes of the SCP.
A comparative study on cyanoprokaryota blooms in Swan River estuary, upper Canning River and upper Serpentine River found that these sites, although hyposaline to saline, contained species that were common in the freshwater lakes. Sampling the river systems showed M. aeruginosa, M. flos-aquae, A. circinalis, A. elenkinii and Planktothrix planctonica to be cosmopolitan in distribution, present in SCP wetlands of varied salinity. Similarities between the upper Canning River and lakes in environmental conditions and species assemblage were demonstrated using multivariate analyses.
Toxin analysis of bloom samples from the Swan River and upper Canning River revealed microcystin concentrations were less than that of the surrounding lakes (1.05-124.16 µg L[superscript]-1). Similarly, nodularin concentrations were higher in Yangebup Lake than the upper Serpentine River. However, the dominance of Anabaena in Canning River samples, and the highly toxic result from the Artemia bioassay suggests microcystin is not the predominant cyanotoxin in this wetland.
This study has produced an overview of the distribution and morphology of cyanotoxin-producing cyanoprokaryotes in the SCP wetlands. The data presented provide the basis for further cyanoprokaryote research in Western Australia, in particular the molecular characterisation of bloom-forming toxic species.
31
Mazzei, Viviana. "Diatoms as tools for inferring changing environmental gradients in coastal, freshwater wetlands threatened by saltwater intrusion". FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3716.
Pełny tekst źródłaStreszczenie:
Saltwater intrusion alters the natural salinity and phosphorus (P) gradients in the oligotrophic, freshwater wetlands located near coastlines of the Caribbean Basin with important consequences to the structure and function of key ecosystem components, including plants, soil microbes, and periphyton. Periphyton communities, particularly diatoms, are extremely sensitive to water quality changes and can serve as excellent bioindicators; however, little is known about their use in detecting novel rates of saltwater intrusion into coastal, freshwater wetlands. I examined the individual and combined effects of elevated salinity and P on periphyton functional processes and diatom composition by conducting transect surveys along salinity and P gradients in the southern Everglades, as well as through mesocosm studies in which salinity and P were experimental manipulated. I demonstrated that conductivity (a proxy for salinity) and P gradients drive spatial patterns in diatom assemblage structure in the southern Everglades and that these assemblages have relatively low conductivity (2 mS cm-1) and total P thresholds (82 µg g-1). These findings were supported by the experimental work which showed that monthly pulses of elevated salinity only ~1 ppt above ambient was sufficient to cause significant shifts in periphytic diatom assemblages along with reduced periphyton productivity, total carbon, and nutrient content. The addition of P to freshwater and salt-treated periphyton significantly elevated mat total P, underscoring the P-uptake efficiency of periphyton. Surprisingly, addition of P to freshwater periphyton did not elicit significant functional or compositional responses, although chlorophyll-aconcentrations and accumulation rates tended to be higher with P. Similar chlorophyll-atrends were observed for salt-treated mats with added P, but these mats also exhibited significantly higher gross primary productivity and net ecosystem productivity compared to all other treatments and a diatom assemblage distinct from any other treatment. This research provides new and valuable information regarding periphyton dynamics in response to changing water sources that will allow us to extend the use of periphyton, and their diatom assemblages, as tools for environmental assessments related to saltwater intrusion in the southern Everglades and other karstic, freshwater wetlands.
32
Schmidt, John Michael. "Litter Decomposition in Created and Adjacent Forested Wetlands of the Coastal Plain of Virginia". Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/43580.
Pełny tekst źródłaStreszczenie:
Litter decomposition is a poorly understood function of constructed and natural forested wetlands. This study compared rates of litter mass loss, changes in litter morphology, and associated macroinvertebrate populations in constructed and natural non-tidal wetlands. Two sets of wetlands (constructed vs. natural) were studied in eastern Virginia; a 9 year-old riparian set near Fort Lee, (FL), and a 2 year-old wet flat set in Charles City County, (CC). Mixed deciduous forest litter collected from the FL natural wetland decayed more rapidly in the created wetlands than the adjacent forested wetlands. Mixed emergent marsh litter collected from the FL created wetland exhibited a similar relationship, although marsh litter decomposed slower than forest litter. Litter area and weight loss followed a similar pattern, although area loss lagged behind weight loss, consistent with an initial leaching phase of decomposition. Both the FL and CC created wetlands exhibited faster litter decomposition than their adjacent forested wetland, however, the FL created wetland had a lower weight:area ratio and higher detritivore abundance than the adjacent forested wetland, while the reverse was true for the CC wetland pair. These relationships suggest macroinvertebrates played an important role in decomposition in the FL created wetland, while other factors were more significant at CC. Faster decomposition in the created wetlands may be of concern for long-term soil organic matter accumulation, or conversely, may indicate quick recovery of the litter decomposition function. Overall, these findings point out the difficulties involved in using certain functional indicators to compare very young and mature systems.Master of Science
33
Johnson, David Edward. "Conserving inter-tidal wetlands : a regional ecosystem-based approach to rehabilitation and recreation". Thesis, Southampton Solent University, 1998. http://ssudl.solent.ac.uk/1274/.
Pełny tekst źródłaStreszczenie:
Integrated Coastal Zone Management (ICZM) depends on the recognition that benefits associated with healthy functioning (function benefits) of ecosystems are irreplaceable in ecological, geomorphological and social terms. A methodology for evaluating different inter-tidal wetlands on the basis of indicators representing their full range of functions is presented. Each inter-tidal wetland is attributed a function related score. These scores are region specific. Whilst they allow a ranking of inter-tidal wetland importance, they do not equate to economic value. A key advantage of this approach is that it quantifies the regional resource, and forms a basis upon which to consider the impact of future pressures and prioritise conservation actions. The methodology has been applied to the Solent and Poole Bay Marine Natural Area (MNA). The 13 inter-tidal wetlands within this region have been scored and ranked, highlighting the relative importance of the large inter-tidal wetlands of Poole, chichester and Langstone Harbours compared with the snmaller inter-tidal wetlands of the north shore of the Isle of Wight. The main challenges facing the conservation of this regional resource are evaluated and the cumulative impact/risk of key pressures is assessed. Lymington/Keyhaven and Southampton Water are considered to be the regional inter-tidal wetlands whose function benefits are most at risk over the next 20 years. A restoration target of 1200 ha of inter-tidal wetland is suggested for the MNA, with a recommendation that re-creation efforts should focus on Chichester Harbour. A detailed case study of the Lymington/Keyhaven inter-tidal wetland is presented. Technical rehabilitation solutions are suggested based on the synthesis of physical and ecological survey date. This research concludes that work to restore inter-tidal wetlands is urgently needed. Such work requires appropriate central Government funding together with a new mechanism, over and above existing compulstory purchase powers, to rationalize coastal landholdings. Investment should concentrate initially on the most easily rehabilitated and re-created sites, to offset the impact of natural forcing mechanisms associated with global environmental change. A role for environmental mediators in identified to raise the political and social acceptability of inter-tidal wetland restoration and a regional ecosystem-based approach is suggested as the best way forward
34
Johnson, Jaimie L. "The Aquatic Community Associated with Native and Invasive Macrophytes in Lake Erie Coastal Wetlands". Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1535382268156399.
Pełny tekst źródła
35
Servais, Shelby M. "Changes in Soil Microbial Functioning in Coastal Wetlands Exposed to Environmental Stressors and Subsidies". FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3821.
Pełny tekst źródłaStreszczenie:
Environmental perturbations are ubiquitous features of ecosystems and shape ecological structure and function. Climate change will alter the intensity and frequency of disturbances and expose ecosystems to novel combinations of useful inputs (subsidies) and harmful inputs (stressors). Coastal wetlands are particularly vulnerable to changing environmental conditions and are increasingly exposed to effects of interacting subsidies and stressors. In particular, the Florida Coastal Everglades, which has experienced accelerated change due to a history of water management practices, is vulnerable to new disturbances associated with climate change. The low-lying Florida Everglades faces multiple disturbances from storm surge, nutrient enrichment, and sea-level rise which will influence its responses to future environmental perturbations. Microbial communities are often used to characterize environmental change because of their high surface area to volume ratio, permeable membrane, and quick turnover rates. Therefore, assessing how microbial function changes can provide insights into how subsidies and stressors interact to alter biogeochemical cycles. I tested how nutrient enrichment can alter ecosystem responses to stress and found that it did not promote recovery in mangrove plants. I examined how long-term exposure to salinity and phosphorus (the limiting nutrient in the Everglades) affected microbial enzyme activity and found that salinity alone acts as a suppressor of enzyme activity but phosphorus addition can mitigate salinity stress in sawgrass soil. I tested how pulses of salinity can affect the microbially-mediated breakdown of organic material and found that the microbial community was functionally redundant and unaffected by saltwater pulses; however, microbial activity was consistently lower in the brackish marsh compared to the freshwater marsh. I investigated how gradients of salinity and phosphorus affected freshwater and brackish soils and determined previous exposure to saltwater intrusion dominates affects microbial function and soil composition. Across these experiments, I found that environmental perturbations alter the microbial-mediated processing of nutrients and carbon, and legacies of previous disturbances influence the microbial response to new disturbance regimes.
36
Loder, Nicholas Mason. "An evaluation of the potential of coastal wetlands for hurricane surge and wave energy reduction". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3139.
Pełny tekst źródła
37
Egnotovich, Michael Steven. "Eutrophication and coastal wetlands linking nutrient enrichment to tidal freshwater marsh ecosystem structure and function /". College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3823.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Marine-Estuarine-Environmental Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
38
Brien, Lynn Ferrara. "Modeling eutrophication vulnerability in coastal Louisiana wetlands impacted by freshwater diversion: a remote sensing approach". Diss., Kansas State University, 2015. http://hdl.handle.net/2097/18999.
Pełny tekst źródłaStreszczenie:
Doctor of PhilosophyDepartment of Geography
Kevin P. Price
A major strategy in response to rapid degradation and loss of Louisiana’s coastal wetlands has been the construction of siphon diversion projects. The diversions are designed to reintroduce nutrient enriched freshwater from the Mississippi River into wetland ecosystems to combat saltwater intrusion and stimulate marsh growth. The lack of consensus regarding the effects of river diversions on nutrient enrichment of wetland ecosystems is coupled with major concerns about eutrophication. Locating, assessing, and monitoring eutrophic marsh vegetation represent major challenges to understanding the impacts of freshwater diversions. As a result, this study was undertaken to investigate the feasibility of modeling eutrophication vulnerability of a coastal Louisiana marsh receiving turbid Mississippi River water. The major objective was to integrate remotely sensed data with field measurements of vegetation biophysical characteristics and historical ecosystem survey data to delineate landscape patterns suggestive of vulnerability to eutrophication. The initial step in accomplishing this goal was to model the spatial distribution of freshwater impacts using satellite image-based turbidity frequency data associated with siphon diversion operation. Secondly, satellite and spectroradiometer band combinations and vegetation indices optimal for modeling marsh biophysical characteristics related to nutrient enrichment were identified. Finally, satellite image data were successfully integrated with measures of historical and concurrent marsh biophysical characteristics to model the spatial distribution of eutrophication vulnerability and to elucidate the impacts of freshwater diversions.
39
Quick, Lynne. "Late Quaternary palaeoenvironments of the southern Cape, South Africa palynological evidence from three coastal wetlands". Doctoral thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/4798.
Pełny tekst źródłaStreszczenie:
Includes abstract.Includes bibliographical references.
Despite significant advances in palaeoenvironmental research in southern Africa, the late Quaternary palaeoenvironmental history of the region remains incomplete as palaeoclimatic proxy records are temporally and spatially discontinuous. The southern Cape is a key focus area within this region as it encompasses the Fynbos Biome, a global biodiversity hotspot, as well as rare Afrotemperate forest patches and is therefore of great botanical importance. As this area includes the transition from southern Africa’s winter rainfall zone to the year-round rainfall zone, it is also important from a climatic perspective.
40
Ward, Raymond. "Landscape and ecological modelling : development of a plant community prediction tool for Estonian coastal wetlands". Thesis, University of Brighton, 2012. https://research.brighton.ac.uk/en/studentTheses/37b928df-19dc-48f5-aad8-08398383fb95.
Pełny tekst źródłaStreszczenie:
Estonian coastal wetlands are of international importance as they support characteristic biological diversity. Their limited extent and distribution mean that these wetlands are of high conservation concern, and as such have been identified as a priority in the European Union Habitats Directive. These wetlands are typified by a flat, extensive landscape, situated between the micro-tidal «0.02m), brackish Baltic Sea and a forest interior. Due to the low relief these wetlands may be under threat from sea level rise. This research consisted of four studies: (i) to determine and quantify the relationship between a range of coastal wetland plant community types, elevation and edaphic conditions. Results demonstrated that plant community distribution was significantly affected by micro-topography and edaphic variability. The majority of the plant communities were discernible in the field by elevation alone and elevation was found to be the factor that could distinguish the greatest number of plant communities. (ii) to determine an appropriate method of interpolating LiDAR elevation data and assess the use of LiDAR data in creating a static correlative model to determine plant community type based on elevation. Results showed that with dGPS calibration the model could accurately predict plant community location. Validation of the model in two further sites showed that the correlative model was able to predict plant community with almost perfect (K 0.81) and moderate agreement (K 0.53) dependent on the site. (iii) to determine sediment accretion rates to complete the dynamic model by analysing the level of radionuclides, 137CS and 210Pb, in discrete core sections. Results showed that during periods of greater storminess sediment accretion increased almost threefold. These sensitivity data were included in the dynamic correlative model. (iv) to assess the effects of sea level rise on plant communities in Estonian coastal wetlands under five sea level scenarios, two accretion rate scenarios and factoring in isostatic uplift rates. Results showed that local sea level will rise in some sites and decrease in others dependent on location and SLR scenario. This study has indicated that in many instances Estonian coastal wetlands will increase in extent in the future due to high rates of sediment accretion, particularly in a scenario with more frequent storms, and isostatic uplift. The study has shown that following validation, calibration and sensitivity analysis LiDAR data can be used to accurately predict plant community type in microtopographical ecosystems. The model developed in this study of Estonian coastal wetlands is likely to be transferable to other appropriate habitats such as tidal, estuarine, and floodplains wetlands.
41
Pantaleoni, Eva. "Assessing Coastal Plain Wetland Composition using Advanced Spaceborne Thermal Emission and Reflection Radiometer Imagery". Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28419.
Pełny tekst źródłaStreszczenie:
Establishing wetland gains and losses, delineating wetland boundaries, and determining their vegetative composition are major challenges that can be improved through remote sensing studies. In this study, we used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to separate wetlands from uplands in a study of 870 locations on the Virginia Coastal Plain. We used the first five bands from each of two ASTER scenes (6 March 2005 and 16 October 2005), covering the visible to the short-wave infrared region (0.52-2.185υm). We included GIS data layers for soil survey, topography, and presence or absence of water in a logistic regression model that predicted the location of over 78% of the wetlands. While this was slightly less accurate (78% vs. 86%) than current National Wetland Inventory (NWI) aerial photo interpretation procedures of locating wetlands, satellite imagery analysis holds great promise for speeding wetland mapping, lowering costs, and improving update frequency. To estimate wetland vegetation composition classs of the study locations, we generated a Classification and Regression Tree (CART) model and a Multinomial Logistic Regression (logit) model, and compared their accuracy in separating woody wetlands, emergent wetlands and open water. The overall accuracy of the CART model was 73.3%, while the overall accuracy of the logit model was 76.7%. Although the CART producer's accuracy (correct category classification) of the emergent wetlands was higher than the accuracy from the multinomial logit (57.1% vs. 40.7%), we obtained the opposite result for the woody wetland category (68.7% vs. 52.6%). A McNemar test between the two models and NWI maps showed that their accuracies were not statistically different. We conducted a sub-pixel analysis of the ASTER images to establish canopy cover of forested wetlands. The canopy cover ranged from 0 to 225 m2. We used visble-near-infrared ASTER bands, Delta Normalized Difference Vegetation Index, and a Tasselled Cap transformation in an ordinary linear regression (OLS) model. The model achieved an adjusted-R2 of 0.69 and an RMSE of 2.73% when the canopy cover is less than 16%. For higher canopy cover values, the adjusted-R2 was 0.4 and the RMSE was19.79%. Taken together, these findings suggest that satellite remote sensing, in concert with other spatial data, has strong potential for mapping both wetland presence and type.Ph. D.
42
Leung, Wai-hung, i 梁偉雄. "The conservation of coastal wetlands, especially the Mai Po marshes, in Hong Kong: problems and prospects". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31253441.
Pełny tekst źródła
43
Cope, Jeff A. "Coastal squeeze of vegetation zones in the Los Cerritos Wetlands| The effect of sea level rise". Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1583669.
Pełny tekst źródłaStreszczenie:
This project assesses the elevation of several vegetation zones of the Los Cerritos Wetlands in Southern California to determine the possible effects of sea level rise on the salt marsh vegetation, the foundation of coastal salt marsh ecology. Steamshovel Sough in the Los Cerritos Wetland contains ideal habitat for the project. This coastal salt marsh is unique in that it abuts artificial elevation gradients of urban development on all sides. The confined nature of the wetland restricts its ability to adjust to future sea levels, a process known as coastal squeeze, which calls the sustainability of this scarce ecosystem into question. In-situ surveying of indicator species Parrish's Glasswort and Pacific Cordgrass (Arthrocnemum subterminale and Spartina foliosa) revealed the habitat elevations above sea level. Modelling various sea level rise scenarios using the habitat ranges determined through in-site surveying reveal expected future habitat zones. Los Cerritos Wetland has a notable susceptibility to sea level rise because of topographic convolutions created by local urban development. One and two foot sea level rise scenarios project substantial zone shifts resulting in pronounced winners and losers. The results here highlight the delicacy of the marsh and its intimate relationship to sea level, and hold a powerful utility to restoration project managers seeking to create a salt marsh that reflects the natural distribution of various habitats and which possesses longevity in the face of the changing environment.
44
Ott, Emily Thomas. "Soil Genesis and Vegetation Response to Amendments and Microtopography in Two Virginia Coastal Plain Created Wetlands". Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/83529.
Pełny tekst źródłaStreszczenie:
Wetlands serve important ecosystem functions such as carbon sequestration but are often affected by disturbances like urban development, agriculture, and road building. For wetlands created to mitigate losses, it is important that the ecosystem functions successfully replicate those of natural wetlands. Created wetlands have frequently not provided these functions due to issues including low organic carbon (OC), high soil bulk density (BD), lost topsoil, incorrect hydrology, and failure of targeted vegetation establishment. Organic matter (OM) amendments help created wetlands attain these functions quicker, but, their long-term effects are seldom reported. This research's purpose was to measure the long-term effects of treatments at a sandy tidal freshwater wetland created in 2003 (WWE) and a fine-textured, non-tidal wetland created in 2002 (CCW). We tested OM treatments, topsoil amendment, and microtopography effects on soil and vegetation properties at WWE and OM treatments at CCW. Pedogenic changes in soil morphology, physical and chemical properties were detected by comparing data to previous studies at these sites. At both sites, litter and biomass parameters were measured to estimate total mass C. Herbaceous biomass was measured at WWE. At WWE, no long-term OM treatment effects from 78 or 156 Mg ha-1 were observed. Soils in pits had higher OC, lower BD, and lower chroma than soils on mounds. Sandy and loamy HSFI's developed at WWE within four years, but there were fewer sandy indicators after 12 years. Loamy HSFI's were lost at CCW from 2003 to 2016. Plots at WWE that were amended with topsoil had higher soil mass C than the sandy soil due to a finer texture, but total mass C did not vary. At CCW, long-term OM treatment effects were observed, including lower BD, higher soil mass C, and higher tree mass C with increasing compost rates up to 224 Mg ha-1. Overall, the ideal compost loading rate for constructed wetlands varied with wetland type and mitigation goals. Compost rates of 112 Mg ha-1 are sufficient for short term establishment of wetland vegetation and hydric soil properties, but higher rates near 224 Mg ha-1 may be required for effects that last over 10 years.Ph. D.
45
Spangler, Jonathan Travis. "An Assessment of Floating Treatment Wetlands for Reducing Nutrient Loads from Agricultural Runoff in Coastal Virginia". Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/86656.
Pełny tekst źródłaStreszczenie:
Floating treatment wetlands (FTWs) are an innovative best management practice that can enhance the performance of traditional retention ponds by increasing removal of the nutrients nitrogen (N) and phosphorous (P). FTWs consist of floating rafts on which wetland plants are planted, allowing the roots to be submerged below the water surface while the shoots remain above. A growing body of research has documented FTW performance with regard to urban runoff treatment, however evaluation of FTW effectiveness for treatment of agricultural runoff has received less attention. Due to high fertilization and irrigation rates, commercial nursery runoff contains much higher concentrations of N and P than runoff from urban areas. We conducted this study over two growing seasons (2015 and 2016) to assess the effectiveness of FTWs for use in commercial nursery retention ponds. In the first study we used two different nutrient concentrations, one to simulate nursery runoff (17.1 mg∙L-1 TN and 2.61 mg∙L-1 TP) and one to simulate concentrations that fall between urban and nursery runoff (5.22 mg∙L-1 TN and 0.52 mg∙L-1 TP). Four treatments were used: 1) Pontederia cordata planted in cups supported by a Beemat, 2) Juncus effusus planted in cups supported by a Beemat, 3) a Beemat with no plants, and 4) no treatment (open-water). Performance was evaluated based on a 7-day hydraulic retention time (HRT). Pontederia cordata removed between 90.3% and 92.4% of total phosphorus (TP) and 84.3% and 88.9% total nitrogen (TN), depending on initial loads. These reductions were significantly more than other treatments at both high and low nutrient loading rates. Juncus effusus performed better than the control treatments for TP removal at low nutrient concentrations, but did not perform any better than the control at higher nutrient loads. In the second study, conducted in 2016, we evaluated different plant species over two 8-week trials using simulated nursery runoff. We used five monoculture FTWs with the following species: Agrostis alba, Canna ×generalis, Carex stricta, Iris ensata, and Panicum virgatum. Additionally, two treatments were created from mixed species plantings and the final treatment consisted of an open water control mesocosm. Nutrient removal performance was evaluated over a 7-day HRT. P removal (phosphate-P) by FTW treatments ranged from 26.1% to 64.7% for trial 1 and 26.8% to 63.2% for trial 2. Trial 1 N removal (sum of ammonium-N, nitrate-N, and nitrite-N) efficiencies ranged from 38.9% to 82.4%, and trial 2 ranged from 12.9% to 59.6%. Panicum virgatum removed significantly more N and P than the control and any other FTW treatment in the second study. Both studies indicated, depending upon plant species, that FTWs can effectively remove nitrogen and phosphorous from urban and commercial nursery retention ponds.Master of Science
46
Leung, Wai-hung. "The conservation of coastal wetlands, especially the Mai Po marshes, in Hong Kong : problems and prospects /". Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17457403.
Pełny tekst źródła
47
Anderson, Bert D. "The Distribution and Biogeochemistry of Subtropical Intertidal Microbial Mats". Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7730.
Pełny tekst źródłaStreszczenie:
Microbial mats have played an important role in the carbon (C) and nutrient cycles since the Archean Eon and modern mats are important contributors to the biogeochemistry of intertidal wetlands. Microbial mats are flat assemblages of microbes that are currently found in many unvegetated habitats globally. Intertidal salt pans are a common habitat for microbial mats, however little is known about the distribution of microbial mats within the intertidal landscape. Understanding the spatial distribution of microbial mats is critical to developing quantitative estimates of the impacts of microbial mats on their ecosystems. We photographically measured the presence and density of microbial mats within 1 m2 quadrats across a landscape scale (~1000 Ha) on the Gulf Coast of Florida. The wide variety of metabolic processes that are found within microbial mats makes the net biogeochemical impacts of the microbial mats highly variable as well. To explore the biogeochemistry associated with microbial mats, we measured a suite of soil attributes under microbial mats and compared those measurements to nearby soils without microbial mats. We found that microbial mats are found on soils with biogeochemical attributes that are significantly different than soils without microbial mats. Soil organic matter, nitrate concentration, and soil temperature significantly increased in soils under microbial mats; pH was significantly lower in soils under microbial mats. Also notable was although the concentration of soil organic matter was higher, the bioavailability of that organic matter was significantly lower. Microbial mat presence is correlated with geomorphic variables such as proximal boundaries, as well as neighboring vegetation and other microbial mats.
48
Enwright, Nicholas. "Using Geographic Information Systems for the Functional Assessment of Texas Coastal Prairie Freshwater Wetlands Around Galveston Bay". Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc28416/.
Pełny tekst źródłaStreszczenie:
The objective of this study was to deploy a conceptual framework developed by M. Forbes using a geographic information system (GIS) approach to assess the functionality of wetlands in the Galveston Bay Area of Texas. This study utilized geospatial datasets which included National Wetland Inventory maps (NWI), LiDAR data, National Agriculture Imagery Program (NAIP) imagery and USGS National Land Cover data to assess the capacity of wetlands to store surface water and remove pollutants, including nitrogen, phosphorus, heavy metals, and organic compounds. The use of LiDAR to characterize the hydrogeomorphic characteristics of wetlands is a key contribution of this study to the science of wetland functional assessment. LiDAR data was used to estimate volumes for the 7,370 wetlands and delineate catchments for over 4,000 wetlands, located outside the 100-yr floodplain, within a 2,075 square mile area around Galveston Bay. Results from this study suggest that coastal prairie freshwater wetlands typically have a moderate capacity to store surface water from precipitation events, remove ammonium, and retain phosphorus and heavy metals and tend to have a high capacity for removing nitrate and retainremove organic compounds. The results serve as a valuable survey instrument for increasing the understanding of coastal prairie freshwater wetlands and support a cumulative estimate of the water quality and water storage functions on a regional scale.
49
Wei, Anhua Chow-Fraser Patricia. "Forecasting the response of coastal wetlands to declining water levels and environmental disturbances in the Great Lakes". *McMaster only, 2007.
Znajdź pełny tekst źródła
50
Margo, Michael Ray. "Restoration of resaca wetlands and associated wet prairie habitats at Palo Alto Battlefield National Historic Site". Texas A&M University, 2003. http://hdl.handle.net/1969.1/3918.
Pełny tekst źródłaStreszczenie:
Cultivation and drainage projects associated with livestock production have substantially
disturbed resaca wetlands and wet prairie habitats in southern Texas. As a consequence
of the anthropogenic disturbances, the area of these wetlands has been reduced and the
ecological integrity of the remaining wetlands has been compromised. The goal of this
study was to explore effective strategies for ecological restoration of coastal prairie and
resaca ecosystems in south Texas and provide restoration recommendations to the
National Park Service at Palo Alto Battlefield National Historic Site (NHS). Field
experiments were conducted to evaluate the effectiveness of different approaches for
restoring Spartina spartinae on disturbed saline flats. A resaca hydrologic study was
initiated to evaluate the groundwater hydrology in disturbed versus undisturbed resaca
wetlands and explore potential restoration strategies. Transplanting S. spartinae in the
fall season was more successful (80% survivability) than seeding (0% initial
establishment), spring transplanting (0% survival), spring and fall mechanical
transplanting (0% and 6% survivability, respectively). Soil disturbance significantly
affected (p < 0.05) survival of transplanted tillers and basal diameter of both the bare root and container-grown transplants in the fall manual treatments. The initial
hydrologic study of the resaca wetlands found that vegetation rooting zone hydrology
was likely dependent on surface water rather than groundwater. These findings suggest
that strategies that restore surface hydrologic regimes will likely restore the ecosystem
structure and function of disturbed resacas. Manually transplanting bare-root stock of S.
spartinae in the late fall season without soil disturbance will increase the likelihood of
successful saline flat restoration.