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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Effects of Sediment Removal on Vegetation Communities in Prairie Pothole Wetlands in North Dakota

Smith, Caitlin Langworthy January 2011 (has links)
The goal of this study was to assess effects of sediment removal on vegetation communities in Prairie Pothole wetlands in North Dakota to determine if this management technique is providing desired results to create conditions for ideal vegetation communities in wetlands that will benefit wildlife. This project consists of vegetation surveys from seasonal wetlands located in Benson, Eddy. Towner. and Wells counties in North Dakota. Three types of wetlands were surveyed: natural (reference), excavated (treatment), and converted cropland. Vegetation surveys were completed in the shallow marsh and wet meadow zones of seasonal wetlands. Sites were sampled using a modified Daubenmire method. Aerial photos were assessed to determine the occurrence of drawdown cycles in wetland sites. Plant communities were analyzed using non-metric multidimensional scaling and multi-response permutation procedure was used to make comparisons between sites. The wet meadow zones and shallow marsh zones of the three types of wetlands were all significantly different (p<0.016) from one another. In general, restored wetlands show vegetation trends that liken natural wetlands while those that have been allowed to recover without restoration tend to be cattail choked. When examining hybrid cattail specifically visual obstruction scores were approximately four times greater in converted cropland sites versus treatment or reference sites. Vegetation composition indicates hydrologic conditions (fresh to brackish conditions) of specific sites and regional distribution are likely influential factors in wetland plant establishment. / North Dakota State University / U.S. Fish and Wildlife Service / Ducks Unlimited
42

An investigation into the effect of metals on chlorophyll content and photosynthesis activity of the wetland plant phragmites australis in the lower Diep River, Milnerton, Cape Town

Ayeni, Olutoyosi Olaide January 2011 (has links)
Thesis (MTech (Environmental Management)))--Cape Peninsula University of Technology, 2011. / A study involving a wetland plant, common reed (Phragmites australis L.) was carried out along the bank of the lower Diep River and the adjacent soil samples from four different sites (Milnerton Lagoon, Lower Estuary, Milnerton Bowling Club and Woodbridge Island), Cape Town, South Africa. The aim was to determine the extent of metal contamination and its impact on physiological indices. Results showed that among the metals evaluated, AI and Fe were consistently higher in all the soil samples (from both river bank and the adjacent soil) followed by Zn, Mn, Pb, Cu, Cd, Co, Cr and Ni. The concentrations of AI in the river banks ranged between 1214.1 - 3176 mg.kg-1 compared with the adjacent soils, where AI concentration ranged from 434.8 - 2445.4 mg.kq". The Fe concentrations from the river bank values ranged from 1136.4 - 4897.2 mg.kg-1 compared with Fe concentrations of the adjacent soil samples which ranged from 402.2 - 2459.8 mg.kg-1 . Generally, Zn ranged from 2.4 - 211.5 mq.kq"; Mn: 5.5 - 48.05 mg.kq': Pb: 0.97 - 71.7 mg.kq"; Cu: 0.3 - 45.9 mg.kq'; Cd: 0.0 - 9.3 mg.kq": Co: 0.2 - 2.7 mg.kq': Cr: 0.3 - 2.1 mg.kg-1 ; and Ni: 0.02 - 2.6 mg.kg-1. Overall, Ni had the lovest concentrations in the ecosystem. Results also showed that the abundance of metals from plant samples were in the order of AI > Pb > Cd > Co > Ni > Cr; and for micronutrients, Fe > Mn > Zn > Cu both in the shoots and roots sampled from all the sites investigated. The values of chlorophylls a, b and total chlorophyll as well as photosynthesis were significantly higher in the P. australis plant samples and from the adjacent soil compared with those from the river bank. These results suggest that contamination of soils and wetland ecosystem by metals over and above plant requirements may affect the chlorophyll and photosynthesis rate of the plant thereby undermining the physiological functioning of plants growing along river systems.
43

Testing the Floristic Quality Assessment Index in natural and created wetlands in Mississippi, USA

Herman, Brook Danielle. January 2005 (has links)
Thesis (M.S.) -- Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.
44

The utilisation of the WET-Health and WET-EcoServices tools in the application of Wetland decision making.

Ramburran, Esmeralda. 15 November 2013 (has links)
Wetlands serve many purposes in the landscape and are under increasing threat as a consequence of urbanisation despite their importance directly and indirectly to humans. Through an evaluation of the suitability of the WET-Health and WET-EcoServices tools in determining wetland functionality and the provision of goods and services of the wetlands, it was decided that these tools were particularly appropriate for fulfilling the purpose of this research. WET-Health, used in combination with WET-EcoServices, is effective in determining the overall health of wetlands and provides possible reasons for degradation which reduces the ability of wetlands to supply the benefits associated with the particular hydrogeomorphic type. A feedback and questionnaire survey was conducted with eThekwini municipality to determine if the WET-Health and WET-EcoServices tools satisfied their needs and to ascertain whether these tools would be suitable for management of their wetlands. This research, in collaboration with eThekwini municipality’s Planning Department, seeks to contribute to the management and maintenance of wetlands within the uMdloti Catchment so that more informed wetland management decisions regarding wetland sustainability can be made. A level 1 and 2 WET-Health and WET-EcoServices assessments were applied to three sites namely; the Robert Armstrong, Le Mercy and Lake Victoria Barn swallow roosting wetlands. A WET-Health Level 1 assessment can be considered more feasible than a Level 2 which provides similar results yet is more time consuming, however, expert knowledge and experience with the tool may be necessary. A Level 2 WET-EcoServices assessment is recommended as it not only highlights what benefits are being provided but the extent of each benefit thereof also determining whether a wetland has a greater chance to provide a particular benefit but may not being effective in doing so. This in turn allows for efforts and resources to be directed towards improving wetland management and land-use planning and decision making for which the tools are particularly suitable. The tools were considered appropriate and necessary for wetland management and can be adapted into eThekwini municipality’s work situation. The tools provide a holistic approach for wetland assessment as catchment activities are considered. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
45

The geomorphology of wetlands in the upper Mooi River catchment, KwaZulu-Natal.

Longmore, Jennifer Lyn. January 2001 (has links)
Wetlands are now recognized as being an integral component of the physical landscape. Geomorphology has recently been recognised by wetland scientists as being of fundamental importance in wetland genesis, maintenance and evolution, thereby providing the context for informed, effective wetland management and conservation. At present there exists a paucity of geomorphological wetland research in South Africa. A hydro-geomorphic approach was adopted to attain an understanding of wetland genesis, distribution and functioning of a range of different palustrine wetland systems in the upper Mooi-River Catchment of KwaZulu-Natal. The physical, chemical and landscape-morphological characteristics of wetland soils were investigated to interpret the processes operating within those wetland systems. Both field and laboratory work suggest that wetland creation and maintenance in the upper Mooi River catchment may be attributed primarily to climatic factors, landscape position, landform and geological characteristics. These factors were found to cumulatively control the hydrological characteristics of wetlands, which impart an important influence on internal wetland conditions. While soil properties do not appear to be a primary factor in the establishment of these wetlands, they are nevertheless found to be important in the regulation of the hydrological dynamics of wetland systems. The close interdependence between wetlands and the surrounding landscape and the hydrological cycle is evident in the wetland systems investigated. Geomorphic processes within wetlands such as overbank flooding, overland flow, sedimentation, piping, leaching, soil swelling, shrinkage and cracking and channel incision and dynamics were found to be important variables in determining the nature and internal characteristics of wetland systems. In several of the systems investigated, all of the above mentioned processes were operative, while in other systems, a number of these processes were either insignificant or absent. Canonical Variate Analysis indicated that while commonalities exist between the palustrine wetland systems investigated in this study, significant differences were found between different groups. This supports the argument that a subclassification of the palustrine system into five different palustrine wetland types is warranted. While the scope of the present research did not allow for an extensive investigation of suitable methods of rehabilitation, the study suggests that an understanding of geomorphic process and wetland dynamics will be beneficial to wetland management and conservation as a whole. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.
46

Regional scale modelling of the lower River Murray wetlands: a model for the assessment of nutrient retention of floodplain wetlands pre- and post-management.

Bjornsson, Kjartan Tumi January 2008 (has links)
Most of the lower River Murray and its floodplain wetlands are impacted upon by degradation caused by river regulation. Increasingly the restoration of these ecosystems and the river water quality has become a high priority for federal and state governments and associated departments and agencies. Public concern is adding to the pressures on these departments and agencies to restore these ecosystems and to sustainably maintain the river water quality. The long term monitoring of floodplain wetlands has been limited, compounding the difficulties faced by managers and decision makers on assessing the potential outcome of restoration options. The role of this project in the broad scheme of restoration/rehabilitation is to contribute to the construction of a model capable of increasing managers and decision makers understanding, and build consensus of potential outcomes of management option. This model was to use available data. The developed model, based on WETMOD developed by Cetin (2001), simulates wetland internal nutrient processes, phytoplankton, zooplankton and macrophyte biomass as well as the interaction (nutrient and phytoplankton exchange) between wetlands and the river. The model further simulates the potential impact management options have on the wetlands, and their nutrient retention capacity, and therefore their impact on the river nutrient load. Due to the limitation of data, wetlands were considered in categories for which data was available. Of these two had sufficient data to develop, calibrate and validate the model. Management scenarios for these two wetlands were developed. These scenarios included, the impact of returning a degraded wetland in a turbid state to a rehabilitated clear state, and the impact the removal of nutrient from irrigation drainage inflows has on wetland nutrient retention, and consequent input to the river. Scenarios of the cumulative impact of the management of multiple wetlands were developed based on using these two wetlands, for which adequate data was available, as “exemplar” wetlands, i.e. data from these wetlands were substituted for other similar wetlands (those identified as belonging to the same category). The model scenarios of these multiple wetlands provide some insight into the potential response management may have on individual wetlands, the cumulative impact on river nutrient load and how wetland morphology may relate to management considerations. The model is restricted by data availability and consequently the outputs. Further, some limitations identified during the development of the model need to be addressed before it can be applied for management purposes. However, the model and methods provide a guide by which monitoring efforts can assist in developing future modelling assessments and gain a greater insight not only at the monitoring site but also on a landscape scale. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320131 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008
47

The effect of land use on the species composition of amphibians in North Eastern KwaZulu-Natal.

Russell, Charlene. January 2010 (has links)
Global declines in amphibian species have directed research towards investigating why this is happening. One of the major causes of these declines is the fragmentation and loss of habitat. This study examined the effect of land use on the species composition of frogs within North Eastern KwaZulu-Natal, and the use of buffer zones to facilitate the protection of these species. Three land use types were investigated: sugar cane (Saccharum officinarum), gum (Eucalyptus sp.) plantations and conservation areas. The average number of frog species differed between areas: conservation 13.2 ± 6.6; plantations 3.8 ± 1.3; and sugar cane 2.8 ± 1.4. Sugar and gum plantation were found to be lacking the wetland and grassland/woodland habitats. In addition to this, the frog species that were not present on these land use types were those that are totally dependent on water as well as those that are not dependent on a water source. Two species were highlighted as possible indicator species of land use: Amietophrynus gutturalis and Hyperolius marmoratus. To mitigate the effect of these land use types, the use of buffer zones was explored in a desktop study. A range of buffer zones were applied to wetlands in a sample study area, using a range of distances including the distances of 290 m and 159 m recommended by Semlitsch and Bodie (2003), and the recommended distances for wetlands in South Africa of 10-20 m. The application of a 290 m and 159 m buffer zone on a conglomerate of wetlands connected by a 100m buffer was the most feasible as it incorporated a percentage of the total study (6.4% and 4.3%) area similar to the percentage occupied by the recommended 20m buffer zone (5.5%) around all wetlands, and still incorporated the range under protection put forward by Semlitsch and Bodie (2003). Management implications of these findings are discussed. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
48

Characterisation of the hydrological processes and responses to rehabilitation of a headwater wetland of the Sand River, South Africa.

Riddell, Edward Sebastian. January 2011 (has links)
The erosion of headwater wetlands in the Sand River catchment, in the lowveld of north-eastern South Africa has led to a focus on their rehabilitation, both for livelihood security for those that use them for subsistence agriculture, as well as for provision of streamflow regulation services for the Sand River itself. One such wetland, the Craigieburn-Manalana itself undergoing severe erosion was subject to technical rehabilitation using concrete weirs and gabion dams to stabilize the erosion gullies during 2007. Through a series of papers the research discussed in this thesis examined the response of the wetland?s hydrodynamics to the implementation of these measures. Through the installation of a network of hydrometric apparatus the research has shown that the wetlands hydrology is largely controlled by the presence of both horizontal and vertical clay aquicludes within a hydraulically conductive sandy matrix. The sequence of these aquicludes had allowed for artesian phreatic surface phenomena identified in a relatively hydrologically intact region of the wetland. The gully erosion had initiated hydraulic drawdown of the wetland?s water table leading to the desiccation of the system. The construction of a buttress weir within the erosion gully had restored the wetlands hydrodynamics to that typical of conditions upstream of a clay-plug. The research also explored the role that clay plays in terms of controlling the wetland?s hydro-geomorphic setting through geophysical analysis. A conceptual model was then derived that states that these wetlands are held in place by clay-plugs that form through clay illuviation from the hillslopes at regions of valley confinement. This has important implications for the connectivity of wetland process domains. The research also determined the inputs of surface and subsurface flows to the wetland and it was found through detailed examination of soil moisture responses and variably saturated soil physics modelling using the HYDRUS model, that the wetland is hydrologically connected to its contributing hillslope by threshold induced preferential flow pathways, via macropores, that only respond after specific antecedent soil moisture conditions are met. In addition, the thesis describes novel approaches to use information provided by soil scientists for the development of catchment hydrological models. It was shown that the use of this hydropedology information improved the low flow response function of the catchment model, ACRU. This development has important implications for up-scaling of catchment process domains, or hydrological response units by being able to generalize on hillslope hydrological responses based on configuration of their soil type elements. The research also undertook to examine the role that the wetlands play in catchment processes. It was found through water budgeting, supported by hydrological time-series, stable isotope analysis and the quantification of vegetation water use within the wetland and contributing catchment, that these wetlands do not augment baseflows during the dry season. Furthermore, it is only early on during the wet season that these systems may attenuate peak flows, thereafter they act as conduits for high storm flows. Similarities emanated from this research with previous hydrological studies of headwater wetland systems in southern Africa and these are discussed. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
49

Managing wetlands : a community perspective

Sunday, Jenny M. 04 May 2013 (has links)
Increased residential and commercial development threatens wetland functions, particularly near urban centers. This research explores the values and attitudes of residents concerning wetlands, wetland restoration, and development near Fort Wayne and Huntington, Indiana, the location of a large wetland restoration project. Key Informant interviews were conducted to contextualize issues on wetlands, stormwater management, development, and community involvement. Interviews results were used to generate a random sample, multi-county mail survey. Results show that residents find protecting groundwater, green space, and access to clean drinking water very important. Environmental concern is high regarding flooding, development, and water quality. KI’s underestimate resident’s awareness of water quality issues. A proposed model of significant factors in explaining resident’s attitudes towards wetlands includes whether or not they are a farmer, wetland knowledge, well-being, and positive attitudes towards green space and development. This research is unique because the respondents have exposure to wetland areas on a regular basis. Wetlands are highly appreciated and are an important part of the community. There is a fine balance of property rights and pro-conservation attitudes among residents. Future research can explore whatconservation specifically means to people and how their views on property rights shape that meaning. Results from this research can aid management decisions that can be either beneficial or detrimental to the wetland and those who depend on it for a variety of needs. / Department of Natural Resources and Environmental Management
50

高美濕地經營管理之探討:協力夥伴關係的觀點 / The management of Gaomei Wetland: the view of partnership

李雅慧, Lee,Ya Huei Unknown Date (has links)
我國濕地經營管理現況在政策面、法制面及執行面上,無法建立濕地經營管理無縫的網,在我國濕地經營管理之相關計畫中,相當注重不同利害關係人之參與,又「濕地」係涉及生物習性及牽動人為活動之動態過程,因此,濕地經營管理之協力夥伴關係為何及其良窳相當重要。此外,近年來,人民環保意識抬頭,對於濕地議題之重視性及積極度水漲船高,進而促使政府與地方相關利害團體尋求協力並建立協力夥伴關係,而政府對於有關濕地經營管理之協力夥伴關係所為之影響相關文獻檢閱甚少,故有其探究價值。 本文欲探討「高美濕地」之經營管理,高美濕地於2004年已確立其「台中縣高美野生動物重要棲息環境」及「台中縣高美野生動物保護區」之法定地位,然而,在徒法不足以自行下,高美濕地之經營管理狀況層出不窮,因此,政府與地方相關利害團體,不僅在態度及行為上皆日漸積極,並且形成協力夥伴關係。職是之故,本研究透過蒐集相關文獻、文件及訪談資料,從協力夥伴關係之觀點釐清高美濕地經營管理中,多重利害關係人之協力夥伴關係及檢視是否達成維繫良好協力夥伴關係之條件,並且探究政府對於協力夥伴關係所為之影響。 研究結果發現,高美濕地經營管理之協力夥伴關係有其特殊性,一方面,協力夥伴關係存在中介團體及專家學者之參與呈現外圍性,另一方面,協力夥伴關係之組成上,參與廣度問題致使地方上相關非營利組織在協力關係中產生疏離;再者,維繫高美濕地經營管理協力夥伴關係良好運作條件之檢視,發現高美濕地經營管理之良好運作基本條件存在文獻未提及之「代表性」,其次,良好運作之外在條件並非全部適用於高美濕地經營管理之協力夥伴關係中,此外,良好運作條件之基本前提、外在條件及內在條件三者在高美濕地之運用上產生連動性;最後,政府對於高美濕地經營管理協力夥伴關係之影響上,第一線政府行動者占有相當重要之地位,而且,政府之角色上,政府行動者之影響力遠遠大於政府制度。 / On policy-making、law-making and reinforcement, our wetlands have faced many difficulties in wetland management. The participants of stakeholder emphasis on biology and human-behavior involvement are related to wetland management policies. Therefore, the partnership of wetland is extremely important. Besides, the environmental issues have taken a serious place within people in recent years, which have improved the firm partnership between government and local stakeholder. Since there are lacks of related reviews on researches, it still valued. This research is about management of Gaomei wetland, which has legislatively established “the Taichung county Gaomei wild animals’ essential habitat” and “the Taichung county game park”. However, insufficient of law-enforcement, the obstacles of Gaomei wetland management have became a hot potato. Therefore, the government and the local stakeholder have turned into actively on attitude and behavior, and have formed a firm partnership. Through the collected related reviews、documents, and the interview data , the research clarify the point of Gaomei wetland management on whether the multi-stakeholders’ partnership would view and maintain the well-running condition, and to investigate what would government impact on the partnership. The result indicates that the partnership has feature on Gaomei wetland: On one hand, the partnership which within intermediated group and participant of experts is less-core. On the other hand, the composition of partnership has generated the isolation between the local non-profit organizations. Furthermore, on the view of maintaining Gaomei wetland management , which to keep the well-operation condition, to discover the basic review without representative on well wetland management. And the outside well-operation conditions are not all suitable for the partnership on Gaomei wetland management; in addition, the fundamental premise 、outside and interior of well-operation have generated the relation on Gaomei wetland operation. In conclusion, the government has played the essential role on maintaining the management of wetland and the role of government has greater than institution.

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