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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.
1581

Measuring the recovery of the Benguela Current Large Marine Ecosystem: an application of the DPSIR framework

Mukuvari, Itai 30 April 2015 (has links)
Overfishing in the Benguela Current Large Marine Ecosystem (BCLME) resulted in degradation of the ecosystem. This study used the Driver-Pressure-State-Impact-Response (DPSIR) indicator framework to determine whether the ecosystem is now recovering. Indicator trends were analysed using various data sources that included government institutions and intergovernmental institutions. The results showed that the overall effect of Driver indicators was negative. This was mainly because of socio-economic pressure such as the need to create more jobs in light of rising national unemployment and the declining contribution of the fisheries sector to Gross Domestic Product (GDP). In addition to scientific advice, socio-economic factors also influenced the determination of Total Allowable Catches (TACs). The overall trend of Pressure indicators was positively influenced by the effect of TACs. The TACs reduced the quotas allocated for commercial fishing. Environmental factors did not seem to play a significant role in this study. State indicators had mixed results with the indicators assessed almost split in the middle between those showing a positive trend and those showing a negative trend. On the other hand, Impact and Response indicators showed overall positive results. Therefore, the conclusion of the study was that the degradation of the BCLME has slowed down and there are some signs of recovery. / Environmental Sciences / M.Sc. (Environmental Science)
1582

A community-based approach for evaluating tradeoffs across marine ecosystem services in Oregon

Freeman, Peter M. 28 September 2012 (has links)
As competing uses of our coastlines increase, natural resource agencies are employing marine spatial planning (MSP) to designate areas for different uses or activities in order to reduce conflicts while achieving ecological, economic and social objectives. A central challenge of implementing MSP is development of a rigorous approach for analyzing tradeoffs across the provision of ecosystem services (i.e., the benefits humans receive from nature). This study develops an operational approach to this problem that is founded on community-based methods, ecological production theory, and multi-criteria decision analysis (MCDA). The approach merges ecological models with surveys to identify marine ecosystem services for use in tradeoff analysis. The approach allows for a single set of marine ecosystem services to at once be valued by local stakeholders and measured by biologists, thus connecting social and biological monitoring efforts. To develop the approach in a real-world context, I examined ecosystem services associated with nearshore marine ecosystems in Oregon, where marine reserves are being introduced for biodiversity conservation. I worked with stakeholder focus groups in three Oregon communities to identify 24 marine ecosystem services. I then linked the ecosystem services with ecological indicators, which I then consolidated to derive 11 items for use in a survey-based tradeoff analysis exercise. I administered the survey to a nonrandom sample of stakeholders in Oregon (n=31), from which their relative preferences and preference weights for ecosystem services were derived. The weights and preference measures may then be used in MSP decision-making. Furthermore, I grouped the stakeholder survey data in three ways: by location of residence (coastal vs. non-coastal), by eight categories of affiliation (e.g., business owners, conservationists, commercial and recreational fishers, etc.), and by resource use patterns. I then analyzed the various groupings of stakeholders for within- and between-group homogeneity of preferences. Results of the analyses showed that there are statistically significant variations in preferences within and between most groupings. Capturing the variations in stakeholder preferences is important when developing policies that affect different stakeholder groups. Thus, when implementing the survey instrument, I suggest random sampling of stakeholders stratified by location, affiliation, and resource use. This study provides one of the first examples of a systems-based approach to ecosystem service valuation operationalized to inform MSP, and novel features of the approach have a number of implications for advancing marine research and management. First, by using stakeholders to identify ecosystem services, the approach allows for a tailored implementation of ecosystem-based management at the community level. Second, by integrating ecological and economic information on the provision and value of ecosystem services, the approach provides relevant data for MSP decision-making during the siting, evaluation, and monitoring stages. And third, by applying both stated-preference and MCDA methods, the approach may capture the array of values represented by diverse stakeholder groups. / Graduation date: 2013
1583

Development of a sustainable land and ecosystem services decision support framework for the Mphaphuli Traditional Authority, Limpopo Province, South Africa

Musetsho, Khangwelo Desmond 05 1900 (has links)
This study aimed to investigate the spatial extent of Land-Use Land-Cover (LULC) change and the implications for ecosystem services in order to develop a sustainable land-use management framework for traditional authorities in South Africa. Effectively, this study undertook an insightful examination of the impacts that arise from policy decisions and practices, which unfortunately were found to be ineffective. The methodologies and approaches used in this study included both quantitative and qualitative techniques. The critical quantitative method employed in this research was the use of survey questionnaires to collect primary data. Qualitative approaches, such as one-on-one and key informant interviews, were used to triangulate the findings. Remote sensing and geographic information system (GIS) methods were used to investigate changes in LULC from 1990 to 2018 through the use of data obtained from the South African National Land-Cover project. Stochastic models were used to predict future LULC changes from 2018 to 2050. The Co$ting Nature Policy Support System was used to identify and undertake economic valuation of services provided by ecosystems. Statistical analysis using the Statistical Package for the Social Sciences was used to identify correlations and the reliability of the data, while graphs and tables were generated to identify patterns and lessons from the research. Between 1990 and 2018, significant changes in land cover were noticed for thickets and dense bush, woodlands, waterbodies, subsistence agriculture, and built-up areas. Woodlands changed by over 1 000 hectares (ha) per year, while thickets decreased by over 900 ha per year. Drivers of these changes include deforestation, among others. Future predictions for LULC revealed that between 2018 and 2050, almost 500 ha of woodlands would be lost to built-up areas. The aggregate value of the services flowing from ecosystems was found to be R9 509 044 608.00. A significant issue was that 90% of the traditional leaders interviewed could not positively respond to whether they knew the extent of the land they presided over, which raised questions regarding the effectiveness of their management systems. Recommendations were made in this study to address the limitations identified in the land-use management practices by adapting elements of the main theoretical frameworks, namely the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services framework; the Drivers, Pressures, States, Impacts and Responses framework; the sustainability theory; and the hierarchy of plans, into a new framework designed specifically for traditional leaders, titled the “Traditional leaders land-use decision support framework”. / Environmental Sciences / D. Phil. (Environmental Management)
1584

EN ANALYS OM HUR KVALITATIV VÄRDERING AV EKOSYSTEMTJÄNSTER KAN BIDRA TILL EN MER HÅLLBAR FYSISK PLANERING: EN FALLSTUDIE OM GRÖNBY, SKÅNE. / An analysis of how qualitative evaluation of ecosystem services can contribue to a more sustainable planing of land use: a case study of Grönby, Scania.

Björkman Sjölund, Fanny January 2022 (has links)
Det mänskliga samhället är beroende av de ekosystemtjänster som naturen förser oss med. Trots det finns det mycket som visar att ekosystemtjänster minskar i mängd och funktion. Det största hotet mot ekosystemtjänsterna är en förändrad markanvändning där naturområden exploateras eller förändras i hög grad. För att uppnå en mer hållbar markanvändning ska ekosystemtjänster integreras i fysisk planering. Den metod som vunnit mest slagkraft i det är värdering av ekosystemtjänster. Ekosystemtjänster kan värderas på fyra olika sätt där den monetära värderingen varit enklast att applicera på nuvarande fysisk planering och därför blivit det mest använda. Det finns dock en problematik med att den monetära värderingen av ekosystemtjänster blivit den mest använda. Problemet existerar i att vissa former av ekosystemtjänster inte går att värdera monetärt. Något som skapar en obalans i vilka ekosystemtjänster som framgångsrikt integreras i den fysiska planeringen. Den här studien har utförts för att undersöka vilken roll den kvalitativa värderingen av ekosystemtjänster kan spela i fysisk planering. För att undersöka det utfördes en fallstudie på orten Grönby i Trelleborgs Kommun. Först utfördes en dokumentanalys för att undersöka hur Trelleborgs kommun arbetat med ekosystemtjänster i styrdokument. Sedan utfördes en go-alongintervjustudie där informanter fick värdera de naturområden och ekosystemtjänster som fanns i närområdet. Rollen som den kvalitativa värderingen av ekosystemtjänster kan bidra med är att den har möjligheten att integrera medborgare i den fysiska planeringen för ekosystemtjänster. Resultatet korrelerade genom det med tidigare studier om att kvalitativ värdering bidrar med andra lager, dimensioner, kunskaper och beskrivningar av känslor som andra värderingar av ekosystemtjänster exkluderar. Det belyste även faktorer som bidrar till värderingen. Några av dem faktorerna var: den visuella upplevelsen, möjligheten till aktiviteter, möten med vilda arter och chansen till återhämtning. / The human society is to a great extent dependent on the ecosystem services that nature provides for us. Despite this, there is a lot of evidence showing that ecosystem services decrease both in amount and in function. The greatest threat to ecosystem services is a changein land use. Where natural areas are being exploited or changed in a large scale. To achieve a more sustainable usage of land, ecosystem services is going to be integrated in the planning of land usage. The best available method for integrating ecosystem services is evaluation of ecosystem services. There are four different methods for evaluating ecosystem services wherethe monetary evaluation has gained the greatest breakthrough. The problem however is that some ecosystem services cannot be evaluated in monetary values. Something that cases an imbalance in which types of ecosystem services that is successfully integrated in the planning of land usage. This study aimed to analyze what role that qualitative evaluation of ecosystem services can fulfill in the planning of land usage. To investigate that, a case study was conducted about the area of Grönby in Trelleborgs municipality. Firstly, an analysis over policy documents from Trelleborgs municipality were analyzed to gain an understanding of the municipality’s work with ecosystem services. A qualitative evaluation of the surrounding ecosystem services was conducted by interviewing local residents in a go-along interview. The role that qualitative evaluation of ecosystem services can provide is that it offers local residents to participate in the planning of land use. The result of the study correlated with former studies that qualitative evaluation of ecosystem services can highlight other types of layers, dimensions, knowledge, and description of emission that other method of evaluation of ecosystem services excludes. In the study there was also some findings about which types of factors that affect the qualitative evaluation of ecosystem services. Some of the factors were: the visual experience, the possibility to participate in activities in the natural areas, the encounter with wildlife and the opportunity for recovery.
1585

Ecosystem-Based Management of the Lake Erie Ecosystem: A Survey-Based Approach to Assessment of Management Needs

Wilson, Gregory B. 08 April 2011 (has links)
No description available.
1586

Echanges de CO2 atmosphérique dans la lagune d’Arcachon et relations avec le métabolisme intertidal / Atmospheric CO2 exchange in the Arcachon lagoon and relationships with the intertidal metabolism

Polsenaere, Pierre 29 April 2011 (has links)
Les zones côtières ne sont prises en compte dans les budgets globaux de CO2 atmosphérique que depuis peu. Il s’avère que bien qu’elles ne représentent globalement que de faibles superficies, les flux de carbone et de nutriments y sont très significatifs à l’échelle globale. On sait peu de chose sur le comportement des écosystèmes lagunaires vis-à-vis du CO2 et, encore moins des zones intertidales où les échanges avec l’atmosphère ont lieu alternativement avec l’eau et le sédiment. Les objectifs de cette étude ont été d’une part, d’établir le bilan de carbone échangé entre la lagune d’Arcachon, l’atmosphère et le milieu terrestre, et d’autre part de mettre en relation ces flux avec la production nette de l’écosystème (NEP) afin de mieux caractériser le statut métabolique de celle-ci ainsi que les facteurs environnementaux clés. Pour cela, nous avons mis en place pour la première fois et à différentes saisons et stations, des mesures directes de flux de CO2 par Eddy Corrélation, une méthode fonctionnant en continu pendant l’immersion et l’émersion. En parallèle, les apports de carbone terrestre sous ses différentes formes ont été quantifiés par un suivi annuel sur 9 rivières alimentant la lagune. L’export total de carbone par le bassin versant à travers les eaux de surface des rivières est estimé à 116 t C km-2 an-1 dont 39% est exporté à la lagune sous forme organique dissoute (DOC) du fait de la prédominance de podzols dans le bassin versant. La forte minéralisation de la matière organique terrestre dans les sols et eaux souterraines sursature largement les eaux en CO2 et l’export sous forme de carbone inorganique dissoute (DIC) représente environ 21%. La formulation d’un modèle mathématique, le « StreamCO2-DEGAS », basé sur les mesures de pCO2, de concentrations et de compositions isotopiques en DIC a permis de montrer que 43% de l’export total de carbone était dégazé sous forme de CO2 depuis les rivières vers l’atmosphère, réduisant alors le flux net entrant dans la lagune à 66 t C km-2 an-1. Concernant la mesure de flux verticaux, l’analyse cospectrale ainsi que les résultats obtenus en adéquation avec les contrôles physiques et biologiques aux différentes échelles tidale, diurne et saisonnières, ont permis de valider la méthode de l’Eddy Covariance en zone intertidale. Sur l’ensemble de la période de mesures, les flux de CO2 étaient faibles, variant entre -13 et 19 µmol m-2 s-1. Des puits de CO2 atmosphérique à marée basse le jour ont été systématiquement observés. Au contraire, pendant l’immersion et à marée basse la nuit, des flux positifs ou négatifs ou proche de zéro ont été observés suivant la saison et la station étudiées. L’analyse concomitante des flux de CO2 et des images satellites du platier à marée basse le jour a clairement permis de discriminer l’importance relative des deux cycles métaboliques distincts des principaux producteurs primaires avec (1) les herbiers de Zostera noltii à cycle annuel long, dominant la NEP en été et en automne à la station la plus centrale et (2) les communautés microphytobenthiques, dominant la production primaire brute (PPB) au printemps à la même station et en automne au fond du bassin. Un recyclage rapide de cette production durant l’immersion et l’émersion a aussi clairement été mis évidence. Au vue des différents résultats, la technique d’Eddy Covariance utilisée en zone intertidale laisse envisager d’intéressantes perspectives en termes de connaissances sur les budgets de carbone et les processus écologiques et biogéochimiques dans la zone côtière. / The coastal zone is only taken into account since recently in global carbon budgeting efforts. Although covering globally modest surface areas, carbon and nutrient fluxes in the coastal zone appear significant at the global scale. However, little is known about the CO2 behaviour in lagoons and even less in intertidal zones where exchanges with the atmosphere occur alternatively with the water and the sediment. The purposes of this work are, on one hand, to establish the carbon budget between the Arcachon lagoon, the atmosphere and the terrestrial watershed and on the other hand, to link these fluxes with the net ecosystem production (NEP) and better characterize its metabolic status along with the relevant environmental factors. For the first time, CO2 flux measurements by Eddy Correlation have been carried out at different seasons and stations in the tidal flat. In parallel, the total terrestrial carbon export from river waters has been quantified throughout a complete hydrological cycle in nine watercourses flowing into the lagoon. The total carbon export from the watershed through surface river waters is estimated at 116 t C km-2 yr-1 on which 39% is exported to the lagoon as dissolved organic carbon (DOC) owing to the predominance of podzols in the watershed. Intense organic matter mineralization in soils and groundwaters largely over-saturate river waters in CO2 on which export accounts for 21% as dissolved inorganic carbon (DIC). The mathematical “StreamCO2-DEGAS” model formulation based on water pCO2, DIC concentrations and isotopic composition measurements permits to show that 43% of the total carbon export was degassed as CO2 from the riverine surface waters to the atmosphere, lowering then this latter to 66 t C km-2 yr-1. With respect to the CO2 flux measurements in the lagoon, cospectral analysis and the well accordance of results with physical and biological controls at the tidal, diurnal and seasonal time scales permit to validate the Eddy Correlation technique over tidal coastal zone. CO2 fluxes with the atmosphere, during each period, were generally weak and ranged between -13 and 19 µmol m-2 s-1. Low tide and daytime conditions were always characterized by an uptake of atmospheric CO2. In contrast, during the immersion and during low tide at night, CO2 fluxes where either positive or negative, or close to zero, depending on the season and the site. The concomitant analysis of CO2 fluxes with satellite images of the lagoon at low tide during the day clearly discriminate the relative importance of the two distinct metabolic carbon cycling involving the main primary producers, i.e. (1) the Zostera noltii seagrass meadow predominance on the NEP in autumn and summer in the more central station, with an annual cycling and (2) the microphytobenthos community predominance on the gross primary production (GPP) in spring at the same station and in autumn in the inner part of the bay where a rapid carbon cycling during the immersion and the emersion was clearly highlighted. The different results obtained with the Eddy Correlation technique over tidal flats opens interesting perspectives on the knowledge of the carbon budget and the biogeochemical and ecological processes within the coastal zone.
1587

Ecosystem services, biodiversity and human wellbeing along climatic gradients in smallholder agro-ecosystems in the Terai Plains of Nepal and northern Ghana

Thorn, Jessica Paula Rose January 2016 (has links)
Increasingly unpredictable, extreme and erratic rainfall with higher temperatures threatens to undermine the adaptive capacity of food systems and ecological resilience of smallholder landscapes. Despite growing concern, land managers still lack quantitative techniques to collect empirical data about the potential impact of climatic variability and change. This thesis aims to assess how ecosystem services and function and how this links with biodiversity and human wellbeing in smallholder agro-ecosystems in a changing climate. To this end, rather than relying on scenarios or probabilistic modelling, space was used as a proxy for time to compare states in disparate climatic conditions. Furthermore, an integrated methodological framework to assess ecosystem services at the field and landscape level was developed and operationalised, the results of which can be modelled with measures of wellbeing. Various multidisciplinary analytical tools were utilised, including ecological and socio-economic surveys, biological assessments, participatory open enquiry, and documenting ethnobotanical knowledge. The study was located within monsoon rice farms in the Terai Plains of Nepal, and dry season vegetable farms in Northern Ghana. Sites were selected that are climatically and culturally diverse to enable comparative analysis, with application to broad areas of adaptive planning. The linkages that bring about biophysical and human changes are complex and operate through social, political, economic and demographic drivers, making attribution extremely challenging. Nevertheless, it was demonstrated that within hotter and drier conditions in Ghana long-tongued pollinators and granivores, important for decomposition processes and pollination services, are more abundant in farms. Results further indicated that in cooler and drier conditions in Nepal, the taxonomic diversity of indigenous and close relative plant species growing in and around farms, important for the provisioning of ecosystem services, decreases. All other things equal, in both Nepal and Ghana findings indicate that overall human wellbeing may be adversely effected in hotter conditions, with a potentially significantly lower yields, fewer months of the year in which food is available, higher exposure to natural hazards and crop loss, unemployment, and psychological anxiety. Yet, surveys indicate smallholders continue to maintain a fair diversity of species in and around farms, which may allow them to secure basic necessities from provisioning ecosystem services. Moreover, farmers may employ adaptive strategies such as pooling labour and food sharing more frequently, and may have greater access to communication, technology, and infrastructure. Novel methodological and empirical contributions of this research offer predictive insights that could inform innovations in climate-smart agricultural practice and planning.
1588

Evaluating the spatial and environmental benefits of green space : an international and local comparison on rural areas / Luan Cilliers

Cilliers, Luan January 2015 (has links)
In South Africa, urbanized environments are often studied individually, not taking the surrounding natural environment into account (McConnachie and Shackleton, 2012: 2). Current approaches focussing on the integration of Urban Planning and Urban Ecology seek to address these issues of integrated planning. Urban Ecology practice aims to describe the study of (1) humans in human settlements, of (2) nature in human settlements, and of (3) the joined relationships between humans and nature. Urban Ecology thus forms a major part of Urban and Spatial Planning, with regard to the objectives of sustainable planning and development, green infrastructure planning, and resilience. The role and impact of green spaces to support sustainable human settlements are no new phenomenon (Byrne & Sipe, 2010: 7). This is related to the different benefits which nature provides, referred to in this research as ecosystem services (or environmental benefits) of green spaces. Green spaces, in this sense, are fundamental areas in human settlements, in need of intentional and structured planning approaches to enhance sustainability and said environmental benefits. It is important to realise that the environment in urbanized areas is dependent on the local communities (in terms of conservation and appropriate planning approaches), but that local communities (society) are also dependent on the environment (in terms of certain benefits which are provided by the said green spaces and environment). Rural settlements in South Africa experience various problems and challenges in terms of planning for the environment through green spaces (as well as sustainability), mainly as a result of the fragmentation of these rural areas, the existence of lost spaces, urbanisation, urban sprawl and poverty (Trancik, 1986; Barnett, 1995; IIED, 2000; DEAT, 2006; McMahan et al, 2002). This research attempted to address the challenges of integrated planning and green space provision in a local rural context, by means of: (1) A literature study encompassing research on Urban Ecology; Urban Planning; environmental dimension of planning; provision of ecosystem services; green infrastructure planning; resilience, and relevant policies and legislation; (2) An empirical investigation and comparative evaluation of international case studies, along with a local case study; and (3) drawing conclusions and recommendations for the local case study, based on the international approaches and identified best-practices. This research evaluated the spatial and environmental benefits of green space and enhanced the importance of planning for such benefits in rural South African areas. / MArt et Scien (Urban and Regional Planning), North-West University, Potchefstroom Campus, 2015
1589

Evaluating the spatial and environmental benefits of green space : an international and local comparison on rural areas / Luan Cilliers

Cilliers, Luan January 2015 (has links)
In South Africa, urbanized environments are often studied individually, not taking the surrounding natural environment into account (McConnachie and Shackleton, 2012: 2). Current approaches focussing on the integration of Urban Planning and Urban Ecology seek to address these issues of integrated planning. Urban Ecology practice aims to describe the study of (1) humans in human settlements, of (2) nature in human settlements, and of (3) the joined relationships between humans and nature. Urban Ecology thus forms a major part of Urban and Spatial Planning, with regard to the objectives of sustainable planning and development, green infrastructure planning, and resilience. The role and impact of green spaces to support sustainable human settlements are no new phenomenon (Byrne & Sipe, 2010: 7). This is related to the different benefits which nature provides, referred to in this research as ecosystem services (or environmental benefits) of green spaces. Green spaces, in this sense, are fundamental areas in human settlements, in need of intentional and structured planning approaches to enhance sustainability and said environmental benefits. It is important to realise that the environment in urbanized areas is dependent on the local communities (in terms of conservation and appropriate planning approaches), but that local communities (society) are also dependent on the environment (in terms of certain benefits which are provided by the said green spaces and environment). Rural settlements in South Africa experience various problems and challenges in terms of planning for the environment through green spaces (as well as sustainability), mainly as a result of the fragmentation of these rural areas, the existence of lost spaces, urbanisation, urban sprawl and poverty (Trancik, 1986; Barnett, 1995; IIED, 2000; DEAT, 2006; McMahan et al, 2002). This research attempted to address the challenges of integrated planning and green space provision in a local rural context, by means of: (1) A literature study encompassing research on Urban Ecology; Urban Planning; environmental dimension of planning; provision of ecosystem services; green infrastructure planning; resilience, and relevant policies and legislation; (2) An empirical investigation and comparative evaluation of international case studies, along with a local case study; and (3) drawing conclusions and recommendations for the local case study, based on the international approaches and identified best-practices. This research evaluated the spatial and environmental benefits of green space and enhanced the importance of planning for such benefits in rural South African areas. / MArt et Scien (Urban and Regional Planning), North-West University, Potchefstroom Campus, 2015
1590

Land-use impacts on biodiversity and ecosystem functioning of complex multitrophic communities

Barnes, Andrew D. 19 November 2015 (has links)
No description available.

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