Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.

Deteriorating quantity and quality of wetland ecosystem services is a major challenge for the conservation of the Lawuba wetland: socioeconomically the most important wetland area in Swaziland. In response, this study was designed to assess local dependent communities’ factual knowledge of the benefits and threats to the wetland, and their attitudes towards its conservation. In addition, the study employed environmental valuation techniques to estimate the annual economic value of the wetland’s fibre provisioning services and four notions of resource rent associated with the harvested fibre: rent on fibre consumed on site as a final product; and rent on fibre transported for 90 kilometres to Manzini market where it is sold, either as a final product or used as an intermediate input in the production of handicrafts. The fibre ecosystem service was specifically selected on account of its socioeconomic significance. Value of the fibre provisioning service was estimated using market price-based methods, while the magnitude of the different notions of resource rent was estimated using the net price method. A random sample of 63 respondents was used to provide data on the benefits, threats, attitudes, and annual economic value which households attach to the harvested fibre. This sample also provided data used to compute the resource rent associated with fibre harvested and consumed on-site. A random sample of 5 respondents provided data used to compute the resource rent on fibre transported and sold in Manzini as a final consumption good. Finally, a random sample of 5 respondents provided data used to compute the resource rent on fibre manufactured at Lawuba and sold in Manzini. Households had high levels of knowledge of the benefits and threats to the Lawuba wetland. They also had positive attitudes towards its conservation. Chi-square and ANOVA tests rejected the null hypothesis of no association between household: (i) knowledge of the benefits derived from the wetland and income (F = 12.67, p = 0.000), (ii) knowledge of the threats endangering the wetland and education (χ2 = 38.474, p = 0.000), (iii) knowledge of the threats endangering the wetland and income (F = 7.25, p = 0.000), (iv) attitudes towards its conservation and income (F = 13.320, p = 0.000) and (v) attitudes towards its conservation and gender (χ2 = 11.854, p = 0.003). The value of fibre provisioning services was estimated at between US $20,310 and US $32,673 per annum, which translates to US $70 per capita per annum. Magnitude of the resource rent increased along the value chain as theory would predict. It was estimated at US $1.92 (for fibre harvested and consumed on site), US $2.27 (for fibre sold at Manzini as a final product), and US $18 (for fibre manufactured at Lawuba and sold in Manzini). Inasmuch as the study established a positive resource rent, no institutions currently exist for rent capture and appropriate re-investment to support sustainable wetland conservation. The study thus recommends the need to set up suitable resource management institutions. / Dissertation (MSc Agric)--University of Pretoria, 2014. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

The Last Glacial Maximum (LGM) was a period of massive range contraction for numerous taxa, including the water-dispersed mangrove species, Rhizophora mangle L. Following the LGM, R. mangle expanded poleward via propagule transport by ocean currents. In this study, we use microsatellite loci to characterize the genetic structure of nine R. mangle populations and compare potential expansion pathways that resulted in the colonization of the Florida peninsula and Caribbean islands. Results show comparatively greater genetic connectivity between the Caribbean mainland and Florida, a similar pattern between West Africa and Caribbean islands, and substantial admixture on the island of San Salvador, the Bahamas. We conclude that Florida and Caribbean island R. mangle populations were likely recolonized via different expansion pathways. Estimates of recent migration rates are low and populations are structured into three regions (Caribbean mainland, Caribbean islands, Florida). These findings provide insight for future management and conservation initiatives. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Call-response surveys were conducted to better delineate and estimate the population of the nationally threatened least bittern and their habitat requirements in southern Manitoba, Canada. Other marsh bird species whose populations are believed to be declining due to wetland loss throughout, or in parts of, their range were also surveyed including the American bittern, pied-billed grebe, sora, Virginia rail and yellow rail. Surveys were conducted during the 2003 and 2004 breeding seasons within 46 different wetlands. Least bitterns were encountered on 26 occasions at 15 sites within 5 wetlands. The sora was the most abundant and widely distributed target species and was encountered on 330 occasions in 39 of the 46 surveyed wetlands. Yellow rails were not detected during either survey year due to survey methodology. Use of the call-response survey protocol led to an increase in the numbers of all target species detected. This increase was more significant for the least bittern, sora and Virginia rail. Habitat was assessed as percent vegetation cover within a 50-m radius around the calling sites, and forest resource inventory data were used in a Geographic Information System to determine the landscape composition within a 500-m radius around the sites and within a 5-km radius around the wetlands surveyed. Logistic regression analyses were used to evaluate the relationship between the presence of the target species and the site and landscape characteristics. The target species responded differently to different site and landscape characteristics. Least bittern and pied-billed grebe selected areas with higher proportions of Typha spp. and tall shrubs; American bittern also selected areas with higher proportions of tall shrubs. At the 5-km scale, the American bittern responded positively to the amount of wetland and some positive trends were also detected for the pied-billed grebe. Sora and Virginia rail were not associated with any of the measured landscape characteristics. One of the most important steps towards the conservation of marsh bird species in Manitoba and elsewhere is the development, adoption, and implementation of a standardized survey protocol. Based on the results of the present study, I recommend that future surveys include both a passive and call-broadcast period for marsh bird species. Future surveys should be conducted in both the morning and evening and sites should be visited 3 times each during the breeding season. In southern Manitoba, call-response surveys should begin as early as the beginning of May to ensure the survey incorporates the period of peak vocalization. I recommend that future yellow rail surveys be conducted after dark. In this study many of the target species selected sites that had a greater area of wetland habitat surrounding them. Future wetland conservation efforts should focus on the protection and/or restoration of wetland complexes to ensure that remaining wetlands do not become smaller and increasingly isolated from one another. In addition, the Rat River Swamp was found to be the most productive marsh complex for least bittern in southern Manitoba. Measures should be taken to protect this area from future development and alteration. / May 2006

Call-response surveys were conducted to better delineate and estimate the population of the nationally threatened least bittern and their habitat requirements in southern Manitoba, Canada. Other marsh bird species whose populations are believed to be declining due to wetland loss throughout, or in parts of, their range were also surveyed including the American bittern, pied-billed grebe, sora, Virginia rail and yellow rail. Surveys were conducted during the 2003 and 2004 breeding seasons within 46 different wetlands. Least bitterns were encountered on 26 occasions at 15 sites within 5 wetlands. The sora was the most abundant and widely distributed target species and was encountered on 330 occasions in 39 of the 46 surveyed wetlands. Yellow rails were not detected during either survey year due to survey methodology. Use of the call-response survey protocol led to an increase in the numbers of all target species detected. This increase was more significant for the least bittern, sora and Virginia rail. Habitat was assessed as percent vegetation cover within a 50-m radius around the calling sites, and forest resource inventory data were used in a Geographic Information System to determine the landscape composition within a 500-m radius around the sites and within a 5-km radius around the wetlands surveyed. Logistic regression analyses were used to evaluate the relationship between the presence of the target species and the site and landscape characteristics. The target species responded differently to different site and landscape characteristics. Least bittern and pied-billed grebe selected areas with higher proportions of Typha spp. and tall shrubs; American bittern also selected areas with higher proportions of tall shrubs. At the 5-km scale, the American bittern responded positively to the amount of wetland and some positive trends were also detected for the pied-billed grebe. Sora and Virginia rail were not associated with any of the measured landscape characteristics. One of the most important steps towards the conservation of marsh bird species in Manitoba and elsewhere is the development, adoption, and implementation of a standardized survey protocol. Based on the results of the present study, I recommend that future surveys include both a passive and call-broadcast period for marsh bird species. Future surveys should be conducted in both the morning and evening and sites should be visited 3 times each during the breeding season. In southern Manitoba, call-response surveys should begin as early as the beginning of May to ensure the survey incorporates the period of peak vocalization. I recommend that future yellow rail surveys be conducted after dark. In this study many of the target species selected sites that had a greater area of wetland habitat surrounding them. Future wetland conservation efforts should focus on the protection and/or restoration of wetland complexes to ensure that remaining wetlands do not become smaller and increasingly isolated from one another. In addition, the Rat River Swamp was found to be the most productive marsh complex for least bittern in southern Manitoba. Measures should be taken to protect this area from future development and alteration.

Call-response surveys were conducted to better delineate and estimate the population of the nationally threatened least bittern and their habitat requirements in southern Manitoba, Canada. Other marsh bird species whose populations are believed to be declining due to wetland loss throughout, or in parts of, their range were also surveyed including the American bittern, pied-billed grebe, sora, Virginia rail and yellow rail. Surveys were conducted during the 2003 and 2004 breeding seasons within 46 different wetlands. Least bitterns were encountered on 26 occasions at 15 sites within 5 wetlands. The sora was the most abundant and widely distributed target species and was encountered on 330 occasions in 39 of the 46 surveyed wetlands. Yellow rails were not detected during either survey year due to survey methodology. Use of the call-response survey protocol led to an increase in the numbers of all target species detected. This increase was more significant for the least bittern, sora and Virginia rail. Habitat was assessed as percent vegetation cover within a 50-m radius around the calling sites, and forest resource inventory data were used in a Geographic Information System to determine the landscape composition within a 500-m radius around the sites and within a 5-km radius around the wetlands surveyed. Logistic regression analyses were used to evaluate the relationship between the presence of the target species and the site and landscape characteristics. The target species responded differently to different site and landscape characteristics. Least bittern and pied-billed grebe selected areas with higher proportions of Typha spp. and tall shrubs; American bittern also selected areas with higher proportions of tall shrubs. At the 5-km scale, the American bittern responded positively to the amount of wetland and some positive trends were also detected for the pied-billed grebe. Sora and Virginia rail were not associated with any of the measured landscape characteristics. One of the most important steps towards the conservation of marsh bird species in Manitoba and elsewhere is the development, adoption, and implementation of a standardized survey protocol. Based on the results of the present study, I recommend that future surveys include both a passive and call-broadcast period for marsh bird species. Future surveys should be conducted in both the morning and evening and sites should be visited 3 times each during the breeding season. In southern Manitoba, call-response surveys should begin as early as the beginning of May to ensure the survey incorporates the period of peak vocalization. I recommend that future yellow rail surveys be conducted after dark. In this study many of the target species selected sites that had a greater area of wetland habitat surrounding them. Future wetland conservation efforts should focus on the protection and/or restoration of wetland complexes to ensure that remaining wetlands do not become smaller and increasingly isolated from one another. In addition, the Rat River Swamp was found to be the most productive marsh complex for least bittern in southern Manitoba. Measures should be taken to protect this area from future development and alteration.

The hydrology of the Kudumela Wetland, Limpopo Province of South Africa was studied from November 2005 to April 2007, involving both fieldwork and laboratory analyses. This study presents the results of an investigation of the hydrology of the Kudumela Wetland in South Africa, and its contribution to dry season flow in the Mohlapitsi and Olifants Rivers. Initially, 40 Piezometers were installed along seven transects and water levels monitored in order to understand water table level characteristics (fluctuations) with time. Water levels in transects one, three, the right bank portion of transect four and transect six showed fluctuations. Transect two, the left bank portion of transect four and transect five did not show significant temporal changes. The relationships between piezometer water levels, rainfall in the study area and stream flow observed at a river gauging station are not clear. The river within the wetland is a gaining stream because the water table level elevation is above that of the river. This indicates that the wetland is feeding the river. The northern part of the wetland (T1 and T2) is affected by artificial drains and most of the piezometers closest to the river channel showed the lowest variations. The relationships between rainfall, groundwater, and surface water at this site shows that stream flow did not respond quickly to precipitation as expected, even in months when rainfall increased (for example, 74 and 103mm during 08/02/06 and 18/02/06 respectively), and the groundwater levels did not show fluctuations, indicating that groundwater responds gradually to precipitation, and that the relationship between rainfall, groundwater and surface water is complex. The environmental stable isotopes (deuterium and oxygen-18) and the radioactive isotope (tritium) were analyzed, along with field observations of electrical conductivity (EC), pH, total alkalinity (Talka) and some major and minor dissolved ion analyses for tracing water dynamics in the study area. A total of 39 water samples was taken and analyzed from boreholes, auger holes, right bank and left bank drains, various points along the river and springs in four sampling visits to the wetland. The results did not clearly provide a temporal record of isotope and chemical variations in the various sources. Results from the most extensive sampling survey in April 2007 provide the most comprehensive overview of hydrological relationships. Clustering of the stable isotope data suggests that the water samples of upstream and downstream river, auger holes further south and most drains clustered together suggesting a common water source and almost all samples fall above the global (GMWL) and local (Pretoria MWL) meteoric water lines, while some fall between the global and Pretoria meteoric water lines. Six representative water samples were analyzed for major ion concentration. Both cation (Ca, Mg, K, and Na) and anion (HCO3, SO4, Cl, and NO3) analyses in November 2007 confirmed conclusions reached from field observations. The analysis shows that a single type of water (Ca, Mg-HCO3) is involved in the study area. In almost all major ion plots, the right bank drains, upstream river and downstream river samples grouped together in a single cluster. As the means for reliable river flow measurements were not available, except for the gauging station at the outlet of the valley, rough, semi-quantitative estimates were made during several field visits. These, suggest considerable losses of river flow into the gravel/boulder beds at and below a gabion dam at the head of the valley. Three major and several other left bank springs and right bank drains at transects T1 and T2 contributed to the river flow at all times. Along with the isotopic and chemical evidence, these observations have lead to a hypothesis that river water enters the wetland and flows back to the Mohlapitsi River through boulder beds underlying the wetland and through drains on the surface of the argillaceous aquitard covering the more conductive boulder beds. Deeper dolomitic groundwater does not appear to contribute to the water balance at least in the northern half of the wetland. Although environmental isotope and hydrochemistry results may not unequivocally prove this hypothesis they do not contradict it.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 208-216). Description: xiv, 216 leaves : maps ; 29 cm.

Made available in DSpace on 2016-06-02T19:29:12Z (GMT). No. of bitstreams: 1 2388.pdf: 3169628 bytes, checksum: 43b1e64c7e8fa25349e87dc551dfc537 (MD5) Previous issue date: 2009-02-17 / Universidade Federal de Sao Carlos / Wetlands are prioritary ecosystems for conservation due to their vast biological diversity and productivity, besides their many functions and value. In southern Brazil conservative data show that about 90% of the original wetlands are already destroyed due to agricultural expansion, mainly the irrigated rice fields. On the other hand, rice is the most important cereal grown in developing countries, being the main food source for more than half of the world population. Also, a high diversity of plants and animals has been found in these agricultural areas. The main goal of this study was to assess the structure and diversity of macroinvertebrates in rice fields and irrigation canals over the different hydrological phases of the cultivation cycle in an important rice cultivation area in Rio Grande do Sul to preserve the biota in these agroecosystems. Six collections were carried out along a cultivation cycle (June 2005 June 2006) in six rice fields and four irrigation canals in the Coastal Plain of Rio Grande do Sul. Quantitative samples of macroinvertebrates were obtained with a corer inserted 10 cm deep into the sediment, and also qualitative samples with a kick net.The main results obtained were: a total of 26,579 individuals assigned into 119 invertebrate taxa were collected in rice fields and irrigation canals; the maintenance of the dry fields and the flooded fields in the fallow phase favors the setting of a greater amount of macroinvertebrate taxa in the agricultural landscape; the irrigated rice fields can store and keep egg banks and other resistance structures of aquatic invertebrates viable along their cultivation cycle, and the irrigation canals work as habitats for the aquatic invertebrate community, thus assisting to keep the aquatic diversity in these agricultural areas. These results can be used in management plans which aim at reconciling agricultural production and biodiversity conservation in Rio Grande do Sul. / As áreas úmidas são ecossistemas prioritários para a conservação em vista de sua grande diversidade biológica e produtividade, além de suas inúmeras funções e valores. No Sul do Brasil, dados conservativos apontam que aproximadamente 90% das áreas úmidas originais já foram destruídas principalmente devido à expansão agrícola, especialmente de lavouras de arroz irrigado. Por outro lado, o arroz é o cereal mais importante cultivado em países em desenvolvimento, sendo o principal alimento para mais da metade da população mundial. Além disso, uma alta diversidade de espécies de plantas e animais tem sido encontrada nessas áreas agrícolas. O objetivo geral deste estudo foi avaliar a estrutura e a diversidade de macroinvertebrados em lavouras de arroz e em canais de irrigação nas diferentes fases hidrológicas do ciclo de cultivo em uma importante região orizícola do Rio Grande do Sul, visando a conservação da biota nestes agroecossistemas. Foram realizadas seis coletas ao longo de um ciclo de cultivo (junho de 2005 a junho de 2006) em seis lavouras de arroz e quatro canais de irrigação na Planície Costeira do Rio Grande do Sul. Foram obtidas amostras quantitativas de macroinvertebrados utilizando o amostrador do tipo core inserido nos 10 cm superficiais do sedimento, e amostras qualitativas, utilizando uma rede de mão. Os principais resultados obtidos foram: as amostragens resultaram em um total de 26.579 indivíduos distribuídos em 119 táxons de invertebrados coletados nas lavouras de arroz e canais de irrigação; a manutenção de lavouras de arroz com água e sem água no período de resteva favorece o estabelecimento de um maior número de táxons de macroinvertebrados dentro da paisagem agrícola; as lavouras de arroz irrigado são capazes de armazenar e manter viáveis os bancos de ovos e outras estruturas de resistência de invertebrados aquáticos ao longo de seu ciclo de cultivo; e os canais de irrigação funcionam também como hábitats para a comunidade de macroinvertebrados aquáticos, auxiliando na manutenção da biodiversidade aquática nessas áreas agrícolas. Esses resultados podem ser utilizados em planos de manejo que busquem conciliar a produção agrícola com a conservação da biodiversidade no Rio Grande do Sul.

MPM / Oliver Tambo Institute of Governance and Policy Studies