Wetlands are some of the most diverse and productive ecosystems on earth. Water-level fluctuations determine the ecological function of shallow lakes and wetlands. Currently, anthropogenic modification to water-level fluctuations is the leading source of ecological degradation in lake and wetland ecosystems worldwide. I used wading birds nesting in Lake Okeechobee, as a model system to address the challenges of environmental restoration within an ecosystem greatly impacted by anthropogenic activities. Specifically, I 1) identified environmental factors most important for predicting the number of wading bird nests, 2) tested the assumptions of both the match-mismatch and the threshold hypothesis by modeling the relationship between nesting success and prey density with foraging habitat availability, and 3) measured the stress response of Great (Ardea alba) and Snowy Egrets (Egretta thula) to hydrologically-mediated changes in food availability. Collectively, the results suggest that the number of nests was greatest when area of nesting substrate was high and water-levels were moderate (3.9 - 4.4 m). Nest numbers dropped when either nesting substrate or foraging habitat was limited. My investigation into the predictions of the match-mismatch and threshold hypotheses found that indeed, prey density can reduce or intensify the effects of a mismatch event. The interaction of prey density and foraging habitat availability was significant and positive in both models. Saturation thresholds existed for both fledging success (147 prey (m^2)^-1) and total productivity (189 prey (m^2)^-1), above which high concentrations of prey could sustain nesting when foraging habitat availability was low. Finally, my studies of the stress response support the hypothesis that hydrologic factors associated with prey availability play an important role in regulating nesting patterns, although the level of food limitation the birds experience at the lake was not as severe as expected. Model selection identified foraging habitat availability as most influential to the nestling Great Egret stress response, whereas foraging habitat availability and prey density both influenced nestling Snowy Egret stress response. Moreover, the Snowy Egret stress response was more sensitive to changes in prey availability than was the Great Egret stress response. Temperature and foraging conditions influenced yolk corticosterone concentrations for both egret species. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2018. / South Africa is a signatory to the Convention on Wetlands of International Importance especially as Waterfowl Habitat of 1971 (referred to as the Ramsar Convention), which is an international convention making provision for protection and wise use of wetlands. Article 3 of the Ramsar Convention requires signatories to formulate and implement their planning to promote wise use of wetlands within their jurisdiction. “Wise use of wetlands” is defined as “the maintenance of their ecological character, achieved through the implementation of ecosystem approaches, within the context of sustainable development” (Birnie & Boyle, 2009: 674). The concept of wise use has been interpreted to mean sustainable development (de Klemm & Shine, 1999: 47; Birnie & Boyle, 2009: 49; Kiss & Shelton, 2007: 93; Birnie & Boyle, 2009: 674; Sands, 2003: 604), as it pertains to wetlands. Having said this, the National Environmental Management Act 107 of 1998 (NEMA) sets out principles of sustainable development that every organ of state must apply in the execution of their duties. Due to the wise use-sustainable development link, two NEMA principles have been considered to form the basis of this study, i.e. sections 2(4)(l) and 2(4)(r). The first principle places an obligation upon the state to ensure that there is intergovernmental coordination and harmonisation of policies, legislation and action relating to the environment (read to include a wetland); and the second principle is to ensure that specific attention in the management and planning are had to wetlands. Ironically, factors that are identified as hindering wise use include, but are not limited to: conflicting and incomplete sectoral law, absence of monitoring procedures, the absence of legal measures for environmental management of water quantity and quality. Therefore, an analysis will be undertaken to determine the extent to which South Africa’s legislative framework regulating wetland conservation is fulfilling the requirements for the promotion of wise use, through these two principles. Focus was had to environmental and related legislation, policies and regulations that promote and/or constrain wetland conservation and wise use. This study identifies the flaws within the law; and proposes streamlining and, where apposite, amendments to the existing legislative framework regulating wetlands in order for South Africa to fulfil her obligations.

Magister Artium - MA / Wetlands provide various ecosystem services such as provisioning, regulating, supporting, and cultural services which may be directly or indirectly beneficial to humans. The manner in which such wetlands are managed is partly determined by human perceptions of their value. However, climatic variability and climate change put the continued provision of such ecosystems under stress. The result is that certain ecosystem services may be provided to differing extents during anomalously wet or dry years. There is thus uncertainty as to the values ascribed to wetlands by people during varying climatic phases. This thesis focuses on understanding how people perceive the functioning of wetlands within our current climate against a background of climatic variability and climate change. This study explores people’s perceptions regarding the functioning of wetlands and ecosystem services provided during dry and wet years, as an indication of how climatic variability and climate change impact peoples’ perceptions. The data was collected in the wetlands of the Agulhas Plain in the Nuwejaars Catchment. Five wetlands classified and scored using the WETEcoServices tool. In addition, five semi-structured interviews and three participatory mapping exercises with landowners were also undertaken. The study reports on the landowners’ awareness of wetland ecosystems, ecosystem services and climatic variability and climate change. Provisioning, supporting, and cultural ecosystem services are frequently used by landowners, which can be impacted by climatic variability and climate change. The WETEcoService benefits and landowners perceptions of ecosystem services varies, as the WETEcoService direct and indirect ecosystem services are either effective or ineffective in dry and wet years. In contrast to landowners perceptions emphasising the importance of ecosystem services directly beneficial to them. The study recommends that the ecosystem services landowners perceive as important is linked to their interest to guarantee their participation in catchment management. WET-EcoService benefits can inform landowners and managers about ecosystem services degradation and whether their conservation methods are either positively or negatively impacting wetlands.

Wetland, which contains about 20 - 30% of global soil carbon pool (Lal, 2008), is one of the world’s most important environmental resources for long-term carbon storage, and plays a vital role in global carbon cycling, especially in mitigating carbon concentration in the atmosphere. However, it is also the ecosystem that has been most seriously abused and suffering from continuous degradation and loss across the world. During the past few centuries, about 50% of the world’s wetland has been lost due to increasing anthropogenic disturbances and global warming (Mitsch & Gosselink, 2007; Gibbs, 2000; Dugan, 1993; Zedler and Kercher, 2005). One typical example is the wetland in Dongting Lake area of China, which was once China’s largest freshwater wetland and now has become the second one. During the past few decades, the Lake has experienced many significant changes causing the rapid degradation, shrinkage and fragmentation of its wetland. Therefore, monitoring the changes of the Lake wetland in spatial distribution and temporal trend and predicting its potential dynamics under climate change and human induced disturbances are becoming increasingly important for linking policy decision-making with regulatory actions and subsequent land-use activities. The overall objective of this project is to monitor the wetland changes in the Lake area and predict its dynamics in the future using proposed land use and land cover (LULC) classification, change detection and modelling approaches. To start with, this study examined the spatiotemporal dynamics of the Lake wetland patterns during the past half century through analyzing remotely sensed images acquired on six time points, including 1978, 1984, 1994, 2001, 2004, 2009, and 2013. A hybrid knowledge-based classification method which combines supervised and expert classification systems was first applied to conduct image classifications with special attention to the classification accuracy of the wetland categories including water, paddy field, reed and marsh categories. After that, a post-classification based change detection technique was carried out to monitor the dynamics of the Lake wetland. The error matrices and Kappa coefficients were than used to assess the classification accuracy. The classification results demonstrated that the proposed hybrid classification approach could discriminate the wetland categories from others with the high accuracy of 96.9%, 93.7%, 82.6%, and 82.4% for water, paddy field, reed, and marsh categories, respectively. The LULC analysis based on the classification showed that wetland area (reed and marsh) in the Lake area has decreased with a dramatic decrease trend after the Three Gorges Dam being fully operated in 2003. To predict future wetland changes and allocate the changes effectively, an integrated model incorporating the logistic, the Markov, and the Conversion of Land use and its Effects (CLUE-S) models has been developed and utilized to 1) produce the LULC probability surface maps; 2) to simulate the LULC change demand in 2013 and 2025 of which the demand for 2013 was then used for validating the results of this integrated model by comparing with the actual LULC maps of the same year; 3) to allocate the simulated changes of 2013 and 2025 based on the obtained LULC probability surface maps and some user-defined rules including land use conversion rules and conversion elasticity. The results from the model validation indicated that the integrated model performed very well with an overall modelling accuracy and Kappa statistic of 80.2% and 74.9%, respectively. The results also suggested that the wetland area is likely to undergo further decrease of another 256.3 km2 by 2025. In summary, this study focused on the development of a unique and integrated approach for the LULC image classification, change detection and prediction of the wetland area – Dongting Lake region in which the landscape was complex and experiencing fast and dramatic changes due to the construction of the TGD. The approach can be easily extended to other wetland associated studies. By providing the information of the long-term wetland dynamics and simulation of its future changes in the Lake area, this research will also enhance our understanding of wetland resources, their dynamics and relationships with human activity induced disturbances and thus promote our ability to make informed use and wise restoration regulations of wetlands.

The northern slopes of the Uinta Mountains, Utah were previously glaciated and contain many landslides. The Tokewanna Landslide is very large and lacks Quaternary faults. Presumably, increased moisture was the failure trigger. A Quaternary climate record from a cored fen, developed in a small basin between hummocks, was reconstructed using sediment pyrolysis, biomass balance, and magnetic susceptibility. Pyrolysis is used to define Hydrogen Indices that are used to delineate wetter and drier conditions based on the kerogen type - Type III being drier, and Type II wetter. The data were matched to a time/depth curve and compared to other Uinta Mountains climate studies. Pyrolysis, biomass balance, and magnetic susceptibility results indicate drier to wetter conditions from ~11,027 to ~8,800 cal yr BP. This was followed by an increase in precipitation, peaking ~8,060 cal yr BP, and then decreasing. Drying conditions ensued after ~4,800 cal yr BP, and from ~1,700 cal yr BP to modern. Regional studies suggest mid-Holocene Epoch warming; some also indicate increased precipitation during those periods. A study at nearby Little Lyman Lake (Tingstad et al., 2011) displays a plankton percent record similar to the wetness record of the study fen. The fen core record does not indicate wet conditions at its base as expected. The record begins ~11,000 cal yr BP and likely represents an incomplete history of this Holocene fen, as the base of the wetland deposits was not reached.

The purpose of this research was to assess the ability of subsurface flow wetlands, with aeration and vegetation, to remove nitrogen in cold weather climates. Aeration was shown to enhance the wetland cell's ability to remove not only nitrogen but also CBOD, COD, and phosphorus (retention) more effectively. There was a significant difference (p< 0.05) in both total nitrogen and ammonia effluent concentrations comparing aerated to unaerated wetland cells, while no significance was found comparing planted and unplanted wetland cells. The effluent ammonia concentrations from the aerated wetland cells ranged from 2.7 to 5.7 mg N/L, while for unaerated cells effluent concentration ranged from 22 to 23 mg N/L. The effluent total nitrogen concentrations from the aerated wetland cells ranged from 9.0 to 12 mg N/L, while those from unaerated cells ranged from 23 to 24 mg N/L. The effluent concentrations showed no significant difference (p < 0.05) when comparing results of three temperature ranges. There is a correlation when comparing ammonia mass removal rates to mass loading rates. Ammonia removal in the aerated wetland cells ranged from 82 to 95%, while unaerated cells ranged from 39 to 45%. The hydraulic retention times ranged from 3.13 to 4.33 days and the tanks-in-series ranged from 1.46 to 2.84. Using this information the wetland cells were modeled using both the TIS and the PkC* models. The k values (PkC* model) of the aerated wetlands for ammonia ranged from 131 to 221 m/d, while the unaerated wetland cells had values ranging from 20.4 to 36.7 m/d. The models appear to show a good prediction of the effluent ammonia concentration for the unaerated cells but the aerated cells show the model does not effectively capture the effects of aeration.

Multispectral aerial videography was used to reproduce the jurisdictional delineation of wetland area of approximately 50 hectares in Davis County, Utah Imagery from the system consisted of three-band composite with wavelengths covering 550 nm (±10 nm), 650 nm (±10 nm), and 850 nm (±10 nm). The site was overflown at three different flight dates during the 1992 growing season (June 2, July 22, October 1). Imagery resolution varied from 0.56 m to 0.81 m. Mosaiced images were analyzed with a Supervised clustering/maximum likelihood classifier, ISODATA clustering/Euclidan classifier, statistical clustering/maximum likelihood classifier, and fuzzy c-means clustering. Overall accuracies for wetland/upland designations as compared to ground truth data varied from 60% to 75%. The ISODATA method was the poorest performer for all dates and both of two accuracy testing techniques. Supervised clustering and statistical clustering were comparable with a slight edge in accuracy to the supervised clustering. The best all-round performer was the fuzzy c-means algorithm in terms of time spent and accuracy.

>Magister Scientiae - MSc / Improved knowledge is required on the quantity and source of water resources, particularly evident during periods of drought currently being faced in South Africa. There is inadequate knowledge with regards to the flood attenuating properties of wetlands, particularly evident in the ungauged catchments of Southern Africa. This study aims to improve the knowledge on the contribution of flow from tributaries with headwaters in mountainous regions to low lying areas and the effects of wetlands on river flow patterns. Several river flow monitoring sites were established along the major upper tributaries of the Nuwejaars River at which daily water levels were recorded and bi-weekly discharge measurements were conducted. Weather data was collected using four automatic weather stations and three automatic rain gauges’ setup throughout the catchment. Rainfall data coupled with rating curves and daily discharges were used to assess the flow responses of these tributaries to rainfall events. Additionally, stable isotope analysis and basic water quality analysis was used to determine the major sources of flow within the major tributaries. The rainfall and river flow data collected, coupled with the characterization of the wetland was used to determine the flood attenuation capabilities of the wetland. Lastly, a conceptual model based on a basic water balance was developed to further explain the role of the wetland and its effects on river flows. The results showed a 27-hour lag time in peak flows from the upper tributaries at the inflows of the wetland to the outflow. Two of the upper tributaries had flow throughout the year and were fed by springs in the upper mountainous regions of the catchment and all tributaries were largely reliant on rainfall for peak flows. The temporary storage of flows within the wetland occurred as a result of the Nuwejaars River bursting its banks, filling of pools, or ponds and the Voëlvlei Lake. It was concluded that the wetland increased the travel time and decreased the magnitude of flows of the Nuwejaars River. However, due to the fact that wetlands are interlinked on a catchment scale and have a collective effect on flood attenuation this study may be improved by looking at the wetlands within the catchment holistically.

The objective of this thesis is to provide a detailed investigation of phosphorus transformations in constructed wetlands. Five replicate Wetland Units were constructed adjacent the wastewater treatment plant in Richmond, Australia. Each wetland was supplied with secondary or tertiary sewage effluent and planted identically with species of schoenoplectus, Phragmites, and Triglochin. Detention times for each Unit were established at 5 or 15 days. Phosphorus concentrations were monitored routinely at the inlet and outlet of each Unit, with a number of specific studies conducted to investigate internal transformations. These studies, undertaken in 1994 and 1995, determined that plants were the dominant phosphorus store in the short term, during wetland establishment and that sediments were the dominant long-term phosphorus storage compartment. Laboratory investigations indicated that there was no significant role for bacteria or algae in the water column relating to phosphorus sequestering, although microorganisms appeared to have some role in the translocation of phosphorus to soil binding sites. After phosphorus contacted the soil surface, transpiration related entrainment of surface water and direct phosphorus uptake by plants were the dominant mechanisms for causing phosphorus to move deeper through the soil substrate. Removal of phosphorus from the interstitial water was by incorporation to biomass or direct sorption to soil binding sites / Doctor of Philosophy (PhD)

This thesis investigates nutrient contribution to six hyper-eutrophic lakes located within close proximity of each other on the Swan Coastal Plain and 20 kilometres south of the Perth Central Business District, Western Australia. The lakes are located within a mixed land use setting and are under the management of a number of state and local government departments and organisations. These are a number of other lakes on the Swan Coastal Plain for which the majority are less than 3 metres in depth and considered as an expression of the groundwater as their base is below the regional groundwater table throughout most of the year. The limited amount of water quality data available for these six lakes and the surface water and groundwater flowing into them has restricted a thorough understanding of the processes influencing the water quality of the lakes. Various private and public companies and organisations have undertaken studies on some of the individual wetlands and there is a wide difference in scientific opinion as to the major source of the nutrients to those wetlands. These previous studies failed to consider regional surface water and groundwater effects on the nutrient fluxes and they predominantly only investigated single wetland systems. This study attempts for the first time to investigate the regional contribution of nutrients to this system of wetlands existing on the Swan Coastal plain. As such, it also includes new research on the nutrient contribution to some of the remaining wetlands. The research findings indicate that the lake sediments represent a considerable store of nutrients (nitrogen and phosphorus). These sediments in turn control the nutrient status of the lake's water column. Surface water is found to contribute on an event-basis load of nutrients to the lakes whilst the groundwater surprisingly appears to contribute a comparatively low input of nutrients but governs the water depth. Analysis of the regional groundwater shows efficient denitrifying abilities as a result of denitrifying bacteria and the transport is localised. Management recommendations for the remediation of the social and environmental value of the lakes include treatment of the lake’s sediments via chemical bonding or atmospheric oxidation; utilising the regional groundwater’s denitrifying abilities to ‘treat’ the surface water via infiltration basins; and investigating the merits of managed or artificial aquifer recharge (MAR).