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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.
1

Systematic Marine Reserve Design

Stewart, Romola Russell Unknown Date (has links)
Since the first reserve selection algorithm was developed in the early 1980s, systematic approaches to reserve design have attracted widespread support due to their ability to identify repeatable and efficient solutions to conservation planning problems. Yet there has been limited application of these methods to the problem of designing reserve systems for biodiversity conservation in the marine environment. In my dissertation research, I apply systematic methods to examine four fundamental issues in marine reserve system design. These issues consider how conservation planning outcomes are influenced when design constraints such as spatial compactness, efficiency, economic costs and incremental reserve establishment are formulated as part of the reserve design problem. First, I consider the trade-offs between spatial design and cost efficiency. In particular, I examine how well marine reserve systems can satisfy the design requirement to minimise the degree of fragmentation whilst minimising reserve system cost. In this case cost refers to the number of sites required to achieve biodiversity conservation objectives. The second issue is the inefficiency of ad hoc marine reserve system design. In terrestrial systems, ad hoc reserve design has been shown to produce inefficient reserve systems, limiting opportunities to achieve conservation targets. I examine how efficiently South Australia’s existing marine reserves contribute to quantitative conservation targets and introduce a new measure of irreplaceability. This metric reflects the potential value of a site’s contribution to reservation goals, by assessing whether a site is selected more than could be expected from chance alone. Sites selected as often as would be expected by chance, fail to contribute to the design of efficient marine reserve systems and represent an opportunity cost. The third issue addresses the demands on reserve systems to achieve both conservation and socio-economic objectives. Options for the design of marine reserve systems, which achieve better economic outcomes for commercial users without compromising conservation targets, are examined using a cost function that serves to make trade–offs early in the design process. The fourth issue is one of shifting targets and incremental reserve design. The problem was most recently highlighted with the rezoning of the Great Barrier Reef Marine Park, where the amount of no-take areas increased from 5% to over 30% but the original zoning arrangements were left in place. The consequence this has on the efficiency of the final marine reserve system is examined when different starting targets are used as the base. Each issue is examined by formulating planning scenarios using data for South Australia’s state waters as a case study. The marine reserve systems are configured using the mathematical optimisation program MARXAN to examine the complex trade-offs of conservation planning problems. The program offers the flexibility to incorporate new approaches and developing theory in marine conservation into the formal statement of the reserve design problem. The results offer some important insights for the future of marine reserve system design. These include 1) efficient representation of biodiversity is only part of the reserve design problem, with small increases in reserve system cost reported as a trade-off for more spatially compact marine reserve systems, 2) despite spanning less than 4% of South Australian state waters, the existing ad hoc marine reserves presented considerable opportunity costs that did not improve even when conservation targets were increased. Hence ad hoc reserve selection is likely to constrain effective conservation of marine biodiversity by compromising the ability to select more suitable sites, 3) integrating conservation and socio-economic objectives presents opportunities to design representative, efficient and practical marine reserve systems that minimise potential loss to commercial users with only small increases to the areal extent of the reserve system and 4) incrementally changing target levels of reservation has a minor affect on the efficiency of the final reserve system, though is likely to influence which planning units are in the final reserve system.
2

Conservation assessment of South African mammals

Keith, Mark 14 February 2006 (has links)
Clearly established conservation priorities are urgently required for taxa and ecosystems in critical need of conservation. This helps to identify and document taxa most in need of conservation attention, and provides an index of the state of degeneration of biodiversity. Including as much relevant information as possible in a prioritisation assessment will deliver the most accurate classification, yet these variables should not overly complicate the prioritisation process. Conservation assessments depend not just on the taxon’s susceptibility to threat (i.e. risk of extinction, or Red List assessments), but also the conservation value, irreplaceability and nature and intensity of the threats. Research into the value and applicability of conservation prioritisation tools at a regional scale, allowed for the assessment of the extinction risk as well as subsequent priority ranking of South African mammals. At the outset research was directed towards investigating South African mammals in accordance with their respective regional and global World Conservation Union (IUCN) Red List and Red Data Book assessments. The regional Red List assessment drastically improved local knowledge of the current extinction risk of various mammals, and identified 57 marine and terrestrial mammals to be highly threatened. Up to date regional extinction risk assessments, allowed for the investigation of whether a human activity threat index derived from six human activity variables across South Africa could be used to highlight mammals threatened with extinction while also being exposed to high human activity. Evidence indicated various threatened and lower risk mammals were exposed to high human activity throughout their range, pointing to high potential threat and future increase in extinction risk. For relevant prioritisation to take place, components of vulnerability (IUCN Red List assessments, and occupancy data), irreplaceability (endemism and taxonomic distinctiveness), and threat measures (body mass and human density in a taxa distributional range) was introduced into relational priority assessment which allowed for a simplified approach in determining conservation priorities for taxa under various region-specific conditions. The use of different sets of information clearly affected the priority rankings. South African Chiroptera and Carnivora was used as a case study to addresses whether a simple measure of taxonomic diversity can be used as a proxy for different measures of phylogenetic diversity in determining regional conservation priority of taxa, when such information is limited. Evidence does suggest that the utilisation of the simple taxonomic diversity measure may provide the appropriate information on evolutionary diversity. Two theoretical concepts were proposed to address some potential shortcomings in the conservation prioritisation arena. The Orange List method offers a system to identify “species [or taxa] of high national importance or of high conservation value” (South African National Environmental Management: Biodiversity Act 2004). In turn the Green Data List essentially represents a radical shift in the traditional approach to the management of both threatened and invasive taxa. Throughout this thesis, evidence do point to smaller mammals being of high conservation concern in South Africa, with the members from the Orders Rodentia, Chiroptera and Insectivora being constantly identified as high conservation priority. Apart from contributing to our current understanding of the conservation importance/priority of South Africa mammals, this current thesis has resulted in a robust understanding of various assessment techniques. / Thesis (DPhil (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted
3

Implications of global change for important bird areas in South Africa

Coetzee, Bernard W. T. 19 November 2008 (has links)
The Important Bird Areas (IBAs) network of BirdLife International aims to identify sites that are essential for the long-term conservation of the world’s avifauna. A number of global change events have the potential to negatively affect, either directly or indirectly, most bird species, biodiversity in general and associated ecological processes in these areas identified as IBAs. To assist conservation decisions, I assessed a suite of ten landscape scale anthropogenic pressures to 115 Important Bird Areas (IBAs) in South Africa, both those currently placing pressures on IBAs and those that constitute likely future vulnerability to transformation. These threats are combined with irreplaceability, a frequently used measure of conservation importance, to identify the suite of IBAs which are high priority sites for conservation interventions: those with high irreplaceability and are highly vulnerable to anthropogenic threats. A total of 22 (19%) of the South African IBAs are highly irreplaceable and are highly vulnerable to at least some of the pressures assessed. Afforestation, current and potential future patterns of alien plant invasions affect the largest number of highly irreplaceable IBAs. Only 9% of the area of highly irreplaceable IBAs is formally protected. A total of 81 IBAs (71%) are less than 5% degraded or transformed. This result, together with seven highly irreplaceable IBAs found outside of formally protected areas with lower human densities than expected by chance provides an ideal opportunity for conservation interventions. However, all the pressures assessed vary geographically, with no discernible systematic pattern that might assist conservation managers to design effective regional interventions. Furthermore, I used the newly emerging technique of ensemble forecasting to assess the impact of climate change on endemic birds in relation to the IBAs network. I used 50 endemic species, eight bioclimatic envelope models, four climate change models and two methods of transformation to presence or absence, which essentially creates 2400 projections for the years 2070-2100. The consensual projection shows that climate change impacts are very likely to be severe. The majority of species (62%) lose climatically suitable space and 99% of grid cells show species turnover. Five species lose at least 85% of climatically suitable space. The current locations of the South African Important Bird Areas network is very likely ineffective to conserve endemic birds under climate change along a “business a usual” emissions scenario. Many IBAs show species loss (41%; 47 IBAs) and species turnover (77%; 95 IBAs). However, an irreplaceability analysis identified mountainous regions in South Africa as irreplaceable refugia for endemic species, and some of these regions are existing IBAs. These IBAs should receive renewed conservation attention, as they have the potential to substantially contribute to a flexible conservation network under realistic scenarios of climate change. Considering all the global change threats assessed in this study, the Amersfoort-Bethal-Carolina District and the Grassland Biosphere Reserve (IBA codes: SA018; SA020) are the key IBAs in South Africa for conservation prioritisation. / Dissertation (MSc)--University of Pretoria, 2008. / Zoology and Entomology / unrestricted
4

Brand image, brand communication, brand attachment y product irreplaceability en relación al brand loyalty en la categoría telefonía hogar. / Brand image, brand communication, brand attachment and product irreplaceability in relation to brand loyalty in the home telephony category.

Muñante Acaro, Ariana Ximena, Zevallos Málaga, Natalia Ida 07 July 2021 (has links)
En un entorno de pandemia, a causa del covid-19, consideramos necesario determinar la relación entre las variables con los servicios de telecomunicaciones, en especial los servicios de telefonía hogar. La presente investigación tiene como objetivo identificar la cercanía del brand image, brand communication, brand attachment y product irreplaceability en relación al brand loyalty en la categoría de telefonía hogar. La investigación será de tipo cuantitativo, con un alcance correlacional y transversal. Las respuestas estarán en una escala de likert del 1 al 7, y en cuanto a la determinación del instrumento se ha considerado que será adaptación. Asimismo, el análisis será por medio de ecuaciones estructurales y el software será PLS. Para este efecto se trabajará con una muestra de 400 personas entre hombres y mujeres que utilicen algún servicio de telefonía hogar. / Due to the Covid-19 virus, we consider it necessary to determinate the relationship between variables with telecommunication services, especially home services. The goal of the following research is to identify the resemblance between the brand image, brand communication, brand attachment, and product irreplaceability with brand loyalty in the home services category. The answers will be on a likert scale from 1 to 7, and as for the determination of the instrument, it has been considered that it will be an adaptation. Likewise, the analysis will be through structural equations and the software will be PLS. This research will have a quantitative type, with a correlational and transversal reach. To achieve this research, we will be needing 400 people between men and women that use a home phone service. / Trabajo de investigación

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