Oxpecker host-selection in the Salambala conservancy, northeastern Namibia
- Lukubwe, Michael S, Craig, Adrian J F K, Manyangadze, Tawanda
- Authors: Lukubwe, Michael S , Craig, Adrian J F K , Manyangadze, Tawanda
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449934 , vital:74866 , https://doi.org/10.3957/056.053.0166
- Description: By studying the host-selection patterns of oxpecker species, researchers can gain valuable insights into their ecological roles and interactions with different host species. This information is crucial for developing effective conservation strategies that prioritise the protection of oxpeckers and their host populations. The study conducted field observations and recorded data on the number of oxpeckers and their respective host species. Additionally, this study investigated the relationship between host species and host parameters (body mass and hair length) in the Salambala conservancy in northeastern Namibia. Selection and density indices were used to calculate the number of host animals supporting one oxpecker as well as the oxpecker density on a host's body surface. Pentad-based counts of oxpeckers and ungulates were conducted.
- Full Text:
- Date Issued: 2023
- Authors: Lukubwe, Michael S , Craig, Adrian J F K , Manyangadze, Tawanda
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449934 , vital:74866 , https://doi.org/10.3957/056.053.0166
- Description: By studying the host-selection patterns of oxpecker species, researchers can gain valuable insights into their ecological roles and interactions with different host species. This information is crucial for developing effective conservation strategies that prioritise the protection of oxpeckers and their host populations. The study conducted field observations and recorded data on the number of oxpeckers and their respective host species. Additionally, this study investigated the relationship between host species and host parameters (body mass and hair length) in the Salambala conservancy in northeastern Namibia. Selection and density indices were used to calculate the number of host animals supporting one oxpecker as well as the oxpecker density on a host's body surface. Pentad-based counts of oxpeckers and ungulates were conducted.
- Full Text:
- Date Issued: 2023
Persistent effects of historical sea levels on the population structure of a temporary wetland copepod
- Emami-Khoyi, Arsalan, Jooste, Candice M, Wasserman, Ryan J, Dalu, Tatenda, Raath-Krüger, Morgan J, Jansen van Vuuren, Bettine, Teske, Peter R
- Authors: Emami-Khoyi, Arsalan , Jooste, Candice M , Wasserman, Ryan J , Dalu, Tatenda , Raath-Krüger, Morgan J , Jansen van Vuuren, Bettine , Teske, Peter R
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445115 , vital:74348 , https://doi.org/10.1111/fwb.14139
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well‐connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
- Date Issued: 2023
- Authors: Emami-Khoyi, Arsalan , Jooste, Candice M , Wasserman, Ryan J , Dalu, Tatenda , Raath-Krüger, Morgan J , Jansen van Vuuren, Bettine , Teske, Peter R
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445115 , vital:74348 , https://doi.org/10.1111/fwb.14139
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well‐connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
- Date Issued: 2023
Short Course Handouts Bundle for the Training of Trainers Course: Introductory course to facilitating social learning and stakeholder engagement in natural resource management contexts
- Weaver, Martin, Rosenberg, Eureta, Cockburn, Jessica J, Thifhulufhelwi, R, Chetty, Preven, Mponwana, Maletje, Mvulane, P
- Authors: Weaver, Martin , Rosenberg, Eureta , Cockburn, Jessica J , Thifhulufhelwi, R , Chetty, Preven , Mponwana, Maletje , Mvulane, P
- Date: 2023
- Subjects: Social learning , Stakeholder management , Natural resources Management , Community education
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/338822 , vital:62456 , ISBN
- Description: This document is a compilation of the course handouts (materials) developed and produced for the “Training of Trainers” Short Course – the full title of which is the: “Introductory course to facilitating social learning and stakeholder engagement in natural resource management contexts”.
- Full Text:
- Date Issued: 2023
- Authors: Weaver, Martin , Rosenberg, Eureta , Cockburn, Jessica J , Thifhulufhelwi, R , Chetty, Preven , Mponwana, Maletje , Mvulane, P
- Date: 2023
- Subjects: Social learning , Stakeholder management , Natural resources Management , Community education
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/338822 , vital:62456 , ISBN
- Description: This document is a compilation of the course handouts (materials) developed and produced for the “Training of Trainers” Short Course – the full title of which is the: “Introductory course to facilitating social learning and stakeholder engagement in natural resource management contexts”.
- Full Text:
- Date Issued: 2023
Special issue on moult in African birds
- Craig, Adrian J F K, Erni, Birgit
- Authors: Craig, Adrian J F K , Erni, Birgit
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449566 , vital:74830 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2023.2289255
- Description: All birds need to replace worn and damaged feathers on a regular basis. Replacement of the flight feathers (remiges and rectrices) is particularly critical, since these influence the efficiency of flight, which in turn has a direct impact on foraging success, parental care and predator evasion. The remiges and rectrices are by far the largest individual feathers, and thus make up a large proportion of the feather mass that must be replaced. During the moult period, a bird must produce new feather material while coping with a reduction in insulation and waterproofing as well as potentially compromised flight ability. Consequently, the moult period is a critical element in the annual cycle, and its timing should minimise any negative effects on survival and reproduction.
- Full Text:
- Date Issued: 2023
- Authors: Craig, Adrian J F K , Erni, Birgit
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449566 , vital:74830 , https://www.tandfonline.com/doi/pdf/10.2989/00306525.2023.2289255
- Description: All birds need to replace worn and damaged feathers on a regular basis. Replacement of the flight feathers (remiges and rectrices) is particularly critical, since these influence the efficiency of flight, which in turn has a direct impact on foraging success, parental care and predator evasion. The remiges and rectrices are by far the largest individual feathers, and thus make up a large proportion of the feather mass that must be replaced. During the moult period, a bird must produce new feather material while coping with a reduction in insulation and waterproofing as well as potentially compromised flight ability. Consequently, the moult period is a critical element in the annual cycle, and its timing should minimise any negative effects on survival and reproduction.
- Full Text:
- Date Issued: 2023
The Emancipatory Nature of Transformative Agency
- Lotz-Sisitka, Heila, Thifhulufhelwi, Reuben, Chikunda, Charles, Mponwana, Maletje
- Authors: Lotz-Sisitka, Heila , Thifhulufhelwi, Reuben , Chikunda, Charles , Mponwana, Maletje
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436175 , vital:73232 , ISBN 9781009153799 , https://doi.org/10.1017/9781009153799
- Description: Cultural-historical activity theory (CHAT) research has established an impressive body of scholarship that advances social understanding of human agency in the transformation of society, much of which is captured in contributions to this volume (cf. Hopwood (Chapter 15); Sannino (Chapter 2); Stetsenko (Chapter 3); Bal and Bird Bear (Chapter 8)). The main tenets of this work, building on the historical legacy of Vygotsky and Marx, affirm that humans are not passive recipients of external stimuli or influences but are active co-creators of the world (s) they inhabit. They are capable of using and producing cultural tools to take power over their own volitional action (s)(cf. Sannino, 2015, Chap-ter 2 of this volume; Hopwood and Gottshalk, 2017). Vygotsky’s major legacy in coming to understand transformative agency is that the cultural tools produced and used as mediational means are critical in the emergence of transformative agency (Sannino, 2015, 2020, Chapter 2 of this volume; Stetsenko, 2019; Hopwood, Chapter 15 of this volume) and thus in the transformation of human activity. As shown by Sannino (2015, 2020), such tools offer stimulus for volitional action that can break paralysis, especially when conflicts of motives are experienced.
- Full Text:
- Date Issued: 2023
- Authors: Lotz-Sisitka, Heila , Thifhulufhelwi, Reuben , Chikunda, Charles , Mponwana, Maletje
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436175 , vital:73232 , ISBN 9781009153799 , https://doi.org/10.1017/9781009153799
- Description: Cultural-historical activity theory (CHAT) research has established an impressive body of scholarship that advances social understanding of human agency in the transformation of society, much of which is captured in contributions to this volume (cf. Hopwood (Chapter 15); Sannino (Chapter 2); Stetsenko (Chapter 3); Bal and Bird Bear (Chapter 8)). The main tenets of this work, building on the historical legacy of Vygotsky and Marx, affirm that humans are not passive recipients of external stimuli or influences but are active co-creators of the world (s) they inhabit. They are capable of using and producing cultural tools to take power over their own volitional action (s)(cf. Sannino, 2015, Chap-ter 2 of this volume; Hopwood and Gottshalk, 2017). Vygotsky’s major legacy in coming to understand transformative agency is that the cultural tools produced and used as mediational means are critical in the emergence of transformative agency (Sannino, 2015, 2020, Chapter 2 of this volume; Stetsenko, 2019; Hopwood, Chapter 15 of this volume) and thus in the transformation of human activity. As shown by Sannino (2015, 2020), such tools offer stimulus for volitional action that can break paralysis, especially when conflicts of motives are experienced.
- Full Text:
- Date Issued: 2023
The prevalence, uses and cultural assimilation of shrub and tree invasive alien plants in a biodiversity hotspot along the Wild Coast, South Africa
- Wootton, Oscar, Shackleton, Charlie M
- Authors: Wootton, Oscar , Shackleton, Charlie M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401314 , vital:69725 , xlink:href="https://doi.org/10.1080/26395916.2023.2216804"
- Description: Invasive alien plant species (IAPS) frequently offer both ecosystem services and disservices to rural communities with high livelihood dependency on local landscapes. However, biocultural relationships with IAPS may go deeper than just provisioning uses, as they may be assimilated into local belief systems manifest in them becoming embedded in cultural constructions such as naming, stories, songs and ceremonies. It is likely that IAPS that are culturally assimilated will represent a greater conflict of interest in the face of proposed controls of IAPS in biodiversity hotspots where conservation priorities are frequently deemed paramount by external agencies. Using a mixed-methods approach we undertook roadside surveys of 17 selected IAPS along the 250 km Wild Coast section of the Maputaland-Pondoland-Albany biodiversity hotspot, accompanied by questionnaire interviews with 48 local people. The mean number of IAPS per site was four, ranging from zero (only one site) to ten, and local inhabitants deemed the abundance of all but one of the species to be increasing. All species had been in the region for decades, had a vernacular name, and all but one had direct consumptive uses. Species with multiple uses were more widely recognised. However, there was only marginal incorporation of the IAPS into stories, songs and ceremonies, although medicinal uses of some IAPS were for cultural/spiritual needs rather than physical ailments per se. These results show that despite widespread use, there was as yet relatively limited cultural assimilation of the IAPS in the Wild Coast region.
- Full Text:
- Date Issued: 2023
- Authors: Wootton, Oscar , Shackleton, Charlie M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401314 , vital:69725 , xlink:href="https://doi.org/10.1080/26395916.2023.2216804"
- Description: Invasive alien plant species (IAPS) frequently offer both ecosystem services and disservices to rural communities with high livelihood dependency on local landscapes. However, biocultural relationships with IAPS may go deeper than just provisioning uses, as they may be assimilated into local belief systems manifest in them becoming embedded in cultural constructions such as naming, stories, songs and ceremonies. It is likely that IAPS that are culturally assimilated will represent a greater conflict of interest in the face of proposed controls of IAPS in biodiversity hotspots where conservation priorities are frequently deemed paramount by external agencies. Using a mixed-methods approach we undertook roadside surveys of 17 selected IAPS along the 250 km Wild Coast section of the Maputaland-Pondoland-Albany biodiversity hotspot, accompanied by questionnaire interviews with 48 local people. The mean number of IAPS per site was four, ranging from zero (only one site) to ten, and local inhabitants deemed the abundance of all but one of the species to be increasing. All species had been in the region for decades, had a vernacular name, and all but one had direct consumptive uses. Species with multiple uses were more widely recognised. However, there was only marginal incorporation of the IAPS into stories, songs and ceremonies, although medicinal uses of some IAPS were for cultural/spiritual needs rather than physical ailments per se. These results show that despite widespread use, there was as yet relatively limited cultural assimilation of the IAPS in the Wild Coast region.
- Full Text:
- Date Issued: 2023
The trophic position and isotopic niche of a cryptogenic tube-building polychaete in a protected clear-water estuarine bay
- van Rensburg, Hendre, Richoux, Nicole B, Simon, Carol A
- Authors: van Rensburg, Hendre , Richoux, Nicole B , Simon, Carol A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454404 , vital:75341 , xlink:href="https://doi.org/10.1016/j.ecss.2023.108549"
- Description: The Knysna Estuary is a large, clear-water embayment and one of the most important estuaries for conservation in southern Africa. The estuary is detritus-dominated and the benthic food webs have low diversities of carnivores, which may make the estuary vulnerable to invasions through the empty niche hypothesis. In the last two decades, the Knysna Estuary has experienced an increase in the population of the cryptogenic and apparently omnivorous estuarine moonshine worm (Diopatra aciculata). Our goal was to describe the trophic role of D. aciculata. We measured carbon and nitrogen stable isotopes in all the common macrophytes and macroinvertebrates across four seasons to 1) establish the isotopic landscapes of three disparate sites within the Knysna Estuary where D. aciculata occurs, 2) establish whether the trophic level of D. aciculata matches those of other common macroinvertebrates, and 3) establish whether the isotopic niche of D. aciculata overlaps with those of syntopic macroinvertebrates. Communities at the different sites differed in food web width, most likely due to differences in primary producer diversity. Our findings suggested that D. aciculata is a facultative carnivore, and some sub-populations are sustained primarily by animal tissues. Isotopic niche overlap analysis showed that direct competition with other common macroinvertebrate consumers is doubtful and D. aciculata occupies a unique niche within the estuary.
- Full Text:
- Date Issued: 2023
- Authors: van Rensburg, Hendre , Richoux, Nicole B , Simon, Carol A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454404 , vital:75341 , xlink:href="https://doi.org/10.1016/j.ecss.2023.108549"
- Description: The Knysna Estuary is a large, clear-water embayment and one of the most important estuaries for conservation in southern Africa. The estuary is detritus-dominated and the benthic food webs have low diversities of carnivores, which may make the estuary vulnerable to invasions through the empty niche hypothesis. In the last two decades, the Knysna Estuary has experienced an increase in the population of the cryptogenic and apparently omnivorous estuarine moonshine worm (Diopatra aciculata). Our goal was to describe the trophic role of D. aciculata. We measured carbon and nitrogen stable isotopes in all the common macrophytes and macroinvertebrates across four seasons to 1) establish the isotopic landscapes of three disparate sites within the Knysna Estuary where D. aciculata occurs, 2) establish whether the trophic level of D. aciculata matches those of other common macroinvertebrates, and 3) establish whether the isotopic niche of D. aciculata overlaps with those of syntopic macroinvertebrates. Communities at the different sites differed in food web width, most likely due to differences in primary producer diversity. Our findings suggested that D. aciculata is a facultative carnivore, and some sub-populations are sustained primarily by animal tissues. Isotopic niche overlap analysis showed that direct competition with other common macroinvertebrate consumers is doubtful and D. aciculata occupies a unique niche within the estuary.
- Full Text:
- Date Issued: 2023
Two new Poyntonophrynus species (Anura: Bufonidae) highlight the importance of Angolan centers of endemism
- Baptista, Ninda L, Pinto, Pedro V, Keates, Chad, Lobón-Rovira, Javier, Edwards, Shelley, Rödel, Mark-Oliver
- Authors: Baptista, Ninda L , Pinto, Pedro V , Keates, Chad , Lobón-Rovira, Javier , Edwards, Shelley , Rödel, Mark-Oliver
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461572 , vital:76214 , xlink:href="https://zoobank.org/7B5494CC-F8F2-46EA-BB73-D28B13D31CB6"
- Description: The pygmy toad genus Poyntonophrynus is endemic to southern Africa. The morphology of these small toads is conserved. They are usually dully colored, and are predominately adapted to arid conditions. During recent surveys in Angola we found Poyntonophrynus specimens that were not assignable to known species. Using an integrative approach, based on mitochondrial and nuclear DNA, morphology, osteology, biogeography and ecology, we identified three new lineages, and describe two of them as new species. All three lineages are closely related to P. pachnodes, an Angolan endemic species, but they are geographically isolated from it. The new species are morphologically distinguishable, and are associated with two of the most important Angolan centers of endemism: the western escarpment and the central highlands. In order to get a more comprehensive understanding of the osteology of the genus, we also provide an osteological characterization of P. dombensis, which was not available to date. Our findings i) increase the number of earless species in the genus Poyntonophrynus, ii) emphasize southwestern Africa as the cradle of diversification in this genus, iii) report the occurrence of Poyntonophrynus in humid environments, thus showing that these toads are ecologically more variable than previously thought, and iv) underline the importance of further biodiversity studies in Angolan centers of endemism.
- Full Text:
- Date Issued: 2023
- Authors: Baptista, Ninda L , Pinto, Pedro V , Keates, Chad , Lobón-Rovira, Javier , Edwards, Shelley , Rödel, Mark-Oliver
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461572 , vital:76214 , xlink:href="https://zoobank.org/7B5494CC-F8F2-46EA-BB73-D28B13D31CB6"
- Description: The pygmy toad genus Poyntonophrynus is endemic to southern Africa. The morphology of these small toads is conserved. They are usually dully colored, and are predominately adapted to arid conditions. During recent surveys in Angola we found Poyntonophrynus specimens that were not assignable to known species. Using an integrative approach, based on mitochondrial and nuclear DNA, morphology, osteology, biogeography and ecology, we identified three new lineages, and describe two of them as new species. All three lineages are closely related to P. pachnodes, an Angolan endemic species, but they are geographically isolated from it. The new species are morphologically distinguishable, and are associated with two of the most important Angolan centers of endemism: the western escarpment and the central highlands. In order to get a more comprehensive understanding of the osteology of the genus, we also provide an osteological characterization of P. dombensis, which was not available to date. Our findings i) increase the number of earless species in the genus Poyntonophrynus, ii) emphasize southwestern Africa as the cradle of diversification in this genus, iii) report the occurrence of Poyntonophrynus in humid environments, thus showing that these toads are ecologically more variable than previously thought, and iv) underline the importance of further biodiversity studies in Angolan centers of endemism.
- Full Text:
- Date Issued: 2023
Using Citizen Science to Protect Natural Untreated Drinking Water Sources: Natural Springs in Rural Catchments and B3 Municipalities in the Eastern Cape
- Mtati, Nosi, Chetty, Preven, Norman, Yondela, Mvulane, Paulose, Libala, Notiswa, Weaver, Matthew J T, Wolff, Margaret M, Cockburn, Jessica J, Mazibuko, Thembalani
- Authors: Mtati, Nosi , Chetty, Preven , Norman, Yondela , Mvulane, Paulose , Libala, Notiswa , Weaver, Matthew J T , Wolff, Margaret M , Cockburn, Jessica J , Mazibuko, Thembalani
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/425732 , vital:72279 , ISBN 978-0-6392-0550-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/3097 final.pdf
- Description: Citizen science is a well-known mechanism used by researchers to col-lect scientific data working together with citizens. It can also be used by interested and concerned citizens (social activists regarding environ-mental threats) to protect natural occurring things like biodiversity, rare species that are threatened extension and much more. It can be a natu-ral occurring process that evolves with time but it can also have some guidelines of how to monitor, collect, analyse and disseminate data. In this project we used participatory action research processes to co-develop tools (co-create being one of the types of citizen science) with local communities, using their knowledge of their area to monitor and protect natural springs. Springs are useful for providing drinking water for people but also for livestock. In rural areas and small towns where service delivery is not reliable, natural occurring water sources become the reliable supply for these communities. Springs also provide ecosys-tem services as they are a keystone ecological infrastructure. These natural water sources can be threatened by pollution, especially that of livestock which is mostly unattended, because they are sometimes shared by people and animals. This poses health risks to the users. This study co-developed the “spring protection and sustainable use” tool/s that can be used to guide communities and local government on how to protect these important water sources. Citizen science also cre-ates opportunities for learning to take place among the participants as well as the researchers involved.
- Full Text:
- Date Issued: 2023
- Authors: Mtati, Nosi , Chetty, Preven , Norman, Yondela , Mvulane, Paulose , Libala, Notiswa , Weaver, Matthew J T , Wolff, Margaret M , Cockburn, Jessica J , Mazibuko, Thembalani
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/425732 , vital:72279 , ISBN 978-0-6392-0550-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/3097 final.pdf
- Description: Citizen science is a well-known mechanism used by researchers to col-lect scientific data working together with citizens. It can also be used by interested and concerned citizens (social activists regarding environ-mental threats) to protect natural occurring things like biodiversity, rare species that are threatened extension and much more. It can be a natu-ral occurring process that evolves with time but it can also have some guidelines of how to monitor, collect, analyse and disseminate data. In this project we used participatory action research processes to co-develop tools (co-create being one of the types of citizen science) with local communities, using their knowledge of their area to monitor and protect natural springs. Springs are useful for providing drinking water for people but also for livestock. In rural areas and small towns where service delivery is not reliable, natural occurring water sources become the reliable supply for these communities. Springs also provide ecosys-tem services as they are a keystone ecological infrastructure. These natural water sources can be threatened by pollution, especially that of livestock which is mostly unattended, because they are sometimes shared by people and animals. This poses health risks to the users. This study co-developed the “spring protection and sustainable use” tool/s that can be used to guide communities and local government on how to protect these important water sources. Citizen science also cre-ates opportunities for learning to take place among the participants as well as the researchers involved.
- Full Text:
- Date Issued: 2023
Using Facebook user photos to quantify surface water dependency in Southern African arid-zone bird species
- Dixon, Elizabeth A, Smit, Ben
- Authors: Dixon, Elizabeth A , Smit, Ben
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441668 , vital:73905 , https://doi.org/10.1080/01584197.2023.2182223
- Description: Birds need to maintain their hydration by either gaining water from their food or by drinking surface water. Many arid-zone birds do not need to consume surface water to maintain body condition. Conservationists need to better understand avian use of surface water sources to inform management plans in a warming world. In this study, we explored the use of Facebook’s image search as a tool to predict interspecific variations in avian surface water use. There was a significant correlation between the proportion of Facebook photographs of each species associated with surface water, and surface water use indices for these species based on published field studies. These findings suggest that Facebook may be a useful source of data for determining the dependence of bird species on surface water. Future research could address the potential for Facebook and other social media platforms for answering a range of ecological questions relating to avian water dependency.
- Full Text:
- Date Issued: 2023
- Authors: Dixon, Elizabeth A , Smit, Ben
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441668 , vital:73905 , https://doi.org/10.1080/01584197.2023.2182223
- Description: Birds need to maintain their hydration by either gaining water from their food or by drinking surface water. Many arid-zone birds do not need to consume surface water to maintain body condition. Conservationists need to better understand avian use of surface water sources to inform management plans in a warming world. In this study, we explored the use of Facebook’s image search as a tool to predict interspecific variations in avian surface water use. There was a significant correlation between the proportion of Facebook photographs of each species associated with surface water, and surface water use indices for these species based on published field studies. These findings suggest that Facebook may be a useful source of data for determining the dependence of bird species on surface water. Future research could address the potential for Facebook and other social media platforms for answering a range of ecological questions relating to avian water dependency.
- Full Text:
- Date Issued: 2023
A social media analytics framework for decision-making in citizen relationship management
- Authors: Yakobi, Khulekani
- Date: 2022-12
- Subjects: Social Media Analytics -- South Africa , Decision making --Mathematical models , Service delivery
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60048 , vital:62815
- Description: Globally social media has shown unprecedented levels of adoption and Social Media Analytics (SMA) is a rapidly growing topic. For governments, SMA holds the promise of providing tools and frameworks to collect, monitor, analyse and visualise social media data, usually driven by specific requirements from a target application. However, social media data is noisy and unstructured, and organisations struggle to extract knowledge from this data, and convert it into actual intelligence. This study argues that SMA can support intelligent decision-making for Citizen Relationship Management (CzRM). CzRM is a growing effort of governments around the world to strive to respond rapidly to their citizens by fostering a closer relationship thereby creating more effective and efficient service delivery. However, there is a little evidence in literature on empirical studies of any existing decision-making framework for CzRM and SMA adoption. In particular, there is a gap with regards incorporating SMA into decision-making for CzRM of governments, particularly in developing countries like South Africa. The aim of this study was to develop a framework that provides guidelines, including methods and tools, incorporating SMA into decision-making for CzRM in the Gauteng Provincial Government (GPG) and the Free State Provincial Government (FSPG) of South Africa. A Systematic Literature Review (SLR) and conceptual analysis method was conducted to design the Social Media Analytics Framework for Decision-making in the context of CzRM (the SMAF). The findings from the literature review revealed several benefits and challenges with SMA, in particular the shortage of skills, guidelines, methods and tools for SMA. These challenges were used to draft guidelines that were included in the framework, which consists of five components that can be used to derive intelligent information from SMA. The pragmatic philosophy and a case study design was used to generate an in-depth, multifaceted understanding of the underlying problems in the case of the GPG and the FSPG. The German North-West Metropolitan region was used as a third case study to provide a more global perspective and a case of a developed country in terms of Gross Domestic Product. The scope of the study was limited to social media posts by provincial citizens related to CzRM and service delivery. Both formative and summative evaluations of the proposed theoretical framework were conducted. The formative evaluation was conducted v | Page as an Expert Review to receive feedback of the framework from the experts in the field of Computer Science and Information Systems. The findings validated the framework and some minor improvements were made based on the experts’ recommendations. Focus Group Discussions (FGDs) with participants from government managers and decision makers in the three cases were conducted. Case documents for the three cases were collected and reviewed. All collected data was analysed using the Qualitative Content Analysis (QCA) method and common categories and themes were identified. Summative evaluations were conducted in the form of a Field Study, which consisted of an analysis of Twitter data from the three cases, and a closing FGD with Business Intelligence (BI) experts at the primary case of the e-Government department of the GPG. The findings revealed that SMA has been adopted in all three cases; however, while their strategies are comprehensive their implementations are very much in their early stages. The findings also highlighted the status of SMA in government and some potential gaps and areas for implementing the framework. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Yakobi, Khulekani
- Date: 2022-12
- Subjects: Social Media Analytics -- South Africa , Decision making --Mathematical models , Service delivery
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60048 , vital:62815
- Description: Globally social media has shown unprecedented levels of adoption and Social Media Analytics (SMA) is a rapidly growing topic. For governments, SMA holds the promise of providing tools and frameworks to collect, monitor, analyse and visualise social media data, usually driven by specific requirements from a target application. However, social media data is noisy and unstructured, and organisations struggle to extract knowledge from this data, and convert it into actual intelligence. This study argues that SMA can support intelligent decision-making for Citizen Relationship Management (CzRM). CzRM is a growing effort of governments around the world to strive to respond rapidly to their citizens by fostering a closer relationship thereby creating more effective and efficient service delivery. However, there is a little evidence in literature on empirical studies of any existing decision-making framework for CzRM and SMA adoption. In particular, there is a gap with regards incorporating SMA into decision-making for CzRM of governments, particularly in developing countries like South Africa. The aim of this study was to develop a framework that provides guidelines, including methods and tools, incorporating SMA into decision-making for CzRM in the Gauteng Provincial Government (GPG) and the Free State Provincial Government (FSPG) of South Africa. A Systematic Literature Review (SLR) and conceptual analysis method was conducted to design the Social Media Analytics Framework for Decision-making in the context of CzRM (the SMAF). The findings from the literature review revealed several benefits and challenges with SMA, in particular the shortage of skills, guidelines, methods and tools for SMA. These challenges were used to draft guidelines that were included in the framework, which consists of five components that can be used to derive intelligent information from SMA. The pragmatic philosophy and a case study design was used to generate an in-depth, multifaceted understanding of the underlying problems in the case of the GPG and the FSPG. The German North-West Metropolitan region was used as a third case study to provide a more global perspective and a case of a developed country in terms of Gross Domestic Product. The scope of the study was limited to social media posts by provincial citizens related to CzRM and service delivery. Both formative and summative evaluations of the proposed theoretical framework were conducted. The formative evaluation was conducted v | Page as an Expert Review to receive feedback of the framework from the experts in the field of Computer Science and Information Systems. The findings validated the framework and some minor improvements were made based on the experts’ recommendations. Focus Group Discussions (FGDs) with participants from government managers and decision makers in the three cases were conducted. Case documents for the three cases were collected and reviewed. All collected data was analysed using the Qualitative Content Analysis (QCA) method and common categories and themes were identified. Summative evaluations were conducted in the form of a Field Study, which consisted of an analysis of Twitter data from the three cases, and a closing FGD with Business Intelligence (BI) experts at the primary case of the e-Government department of the GPG. The findings revealed that SMA has been adopted in all three cases; however, while their strategies are comprehensive their implementations are very much in their early stages. The findings also highlighted the status of SMA in government and some potential gaps and areas for implementing the framework. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
Beauty from Ashes:short term postfire regeneration of dune fynbos -thicket vegetation in the South Eastern Cape floristic region
- Authors: Gcina, Sinenjongo
- Date: 2022-12
- Subjects: Fynbos ecology – Nelson Mandela University Campus Nature Reserve , Forest fires -- Prevention and control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59666 , vital:62319
- Description: Aim This study aims to provide an understanding and a description of the short-term postfire regeneration and ecology of the fynbos-thicket vegetation on a coastal dune system in the southeastern Cape Floristic Region. Another aim is to assess the recovery of the vegetation community by assessing the growth forms and the disturbance response across a range of species from thicket and fynbos communities and to provide a belowground bud bank classification for each of these species in the coastal dune systems. Location The study site was the Mandela University Reserve and the Noordhoek dune fields, situated in Gqeberha, Eastern Cape, which is part of the south-eastern Cape Floristic Region. The study site hosts thicket-fynbos mosaic vegetation type that occurs in a Mediterranean-Climate Ecosystem (MCE). Methods Firstly, field observations and photographs of plant species were taken weekly to assess and identify the species that were emerging and persisting in the dune system in the first 12 months postfire. Phenological events of the species that emerged (e.g., flowering, fruiting, leaf growth, leaf yellowing, and leaf abscission) were also observed and reported on. Secondly, an excavation of 21 species (e.g., Jamesbrittenia microphylla, Euclea racemosa, Olea exasperata, Searsia laevigata) was conducted to classify the species into their belowground bud bank types. Results There was a rapid emergence of resprouters (facultative resprouters and obligate resprouters) in the first 12 months postfire. This was followed by their growth; primarily occurring after the rainfall events. The dominant resprouting species (facultative resprouters and obligate resprouters) entered the system two weeks after the fire. There was a significant difference in the time to the first emergence of the different regeneration groups postfire (P < 0.001): on average, obligate sprouters (OS) appeared 1 month after fire – two months earlier than facultative sprouters (FS) and four months earlier than non-sprouters (NS). There was no statistical evidence to suggest that the FS and non-sprouters NS emerged at different times postfire; however, most NS species were observed in the system 5 months after fire. 4 Exceptions were the NS species Pelargonium grossularoides and Mesembryanthemum aitonis, both annuals that emerged 1 month after fire. A wide range of OS species that appeared earlier in the system (e.g., Euclea racemosa, Olea exasperata, Searsia laevigata, and Lauridia tetragona) exhibit underground lateral growth with belowground bud banks (BBBs) from which they recover after disturbance. In total, six BBB types were recorded in this study, namely: bud-bearing root, rhizome, rhizophore, woody rhizome, stem tuber, and corms. The bud-bearing root from woody species was the dominant BBB in this system. Main conclusion The return of species that occurs in the first year after fire occurs rapidly in the first 2 months as resprouting species (primarily OS) appear in the system. Following this, the rate of return of species decreases as reseeding species (primarily NS) gradually reestablish and occupy the gaps in the dune fynbos-thicket vegetation. This study has shown that plant species in this ecosystem are adapted to fire disturbance as their populations are able to reestablish through various regeneration strategies, including resprouting from different types of BBB. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Gcina, Sinenjongo
- Date: 2022-12
- Subjects: Fynbos ecology – Nelson Mandela University Campus Nature Reserve , Forest fires -- Prevention and control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59666 , vital:62319
- Description: Aim This study aims to provide an understanding and a description of the short-term postfire regeneration and ecology of the fynbos-thicket vegetation on a coastal dune system in the southeastern Cape Floristic Region. Another aim is to assess the recovery of the vegetation community by assessing the growth forms and the disturbance response across a range of species from thicket and fynbos communities and to provide a belowground bud bank classification for each of these species in the coastal dune systems. Location The study site was the Mandela University Reserve and the Noordhoek dune fields, situated in Gqeberha, Eastern Cape, which is part of the south-eastern Cape Floristic Region. The study site hosts thicket-fynbos mosaic vegetation type that occurs in a Mediterranean-Climate Ecosystem (MCE). Methods Firstly, field observations and photographs of plant species were taken weekly to assess and identify the species that were emerging and persisting in the dune system in the first 12 months postfire. Phenological events of the species that emerged (e.g., flowering, fruiting, leaf growth, leaf yellowing, and leaf abscission) were also observed and reported on. Secondly, an excavation of 21 species (e.g., Jamesbrittenia microphylla, Euclea racemosa, Olea exasperata, Searsia laevigata) was conducted to classify the species into their belowground bud bank types. Results There was a rapid emergence of resprouters (facultative resprouters and obligate resprouters) in the first 12 months postfire. This was followed by their growth; primarily occurring after the rainfall events. The dominant resprouting species (facultative resprouters and obligate resprouters) entered the system two weeks after the fire. There was a significant difference in the time to the first emergence of the different regeneration groups postfire (P < 0.001): on average, obligate sprouters (OS) appeared 1 month after fire – two months earlier than facultative sprouters (FS) and four months earlier than non-sprouters (NS). There was no statistical evidence to suggest that the FS and non-sprouters NS emerged at different times postfire; however, most NS species were observed in the system 5 months after fire. 4 Exceptions were the NS species Pelargonium grossularoides and Mesembryanthemum aitonis, both annuals that emerged 1 month after fire. A wide range of OS species that appeared earlier in the system (e.g., Euclea racemosa, Olea exasperata, Searsia laevigata, and Lauridia tetragona) exhibit underground lateral growth with belowground bud banks (BBBs) from which they recover after disturbance. In total, six BBB types were recorded in this study, namely: bud-bearing root, rhizome, rhizophore, woody rhizome, stem tuber, and corms. The bud-bearing root from woody species was the dominant BBB in this system. Main conclusion The return of species that occurs in the first year after fire occurs rapidly in the first 2 months as resprouting species (primarily OS) appear in the system. Following this, the rate of return of species decreases as reseeding species (primarily NS) gradually reestablish and occupy the gaps in the dune fynbos-thicket vegetation. This study has shown that plant species in this ecosystem are adapted to fire disturbance as their populations are able to reestablish through various regeneration strategies, including resprouting from different types of BBB. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Characterising termite mound spatial patterns in the Eastern Cape Karoo : applying drone remote sensing,GIS and spatial statistics
- Mngcele, Lizalise Sive Nqaba
- Authors: Mngcele, Lizalise Sive Nqaba
- Date: 2022-12
- Subjects: Drone aircraft in remote sensing – Eastern Cape Karoo , Termites , Geographic information Systems – South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59555 , vital:62169
- Description: The Eastern Cape Karoo in South Africa has been earmarked for potential Shale Gas development, which has necessitated the understanding of existing ecosystems to be quantiĄed pre-development, in order to have a baseline against which the exploration can be monitored. Termite mounds as baseline mechanisms, are known to be sensitive to ecosystem disturbance and because of their abundance in the exploration zone, have been studied as indicator species. They are both a surface and subsurface phenomena which makes them an ideal baseline monitoring mechanism. Termite mound height, basal circumference and geospatial data was collected against natural and anthropogenic factors: elevation, vegetation, water, soil, geology, human settlements and roads. Mound distributions were observed across four study sites, and seven plots, using a DJI Phantom 4 Pro drone, an aerial and ground survey. Observed mound data on the drone and aerial survey was compared to that of the ground survey. Overall, the drone survey outperformed the aerial survey in recording accurate termite mound data. This was largely attributed to the scale of the study which gave the drone a competitive advantage. It allowed for drone data to be collected at 40 m altitude with an image resolution of 2-6 cm/pixel on each plot. In addition, drone detection accuracy was improved through the ability to generate digital surface models (DSMs) through point clouds and overlaying them with orthomosaics. Considering observed mound spatial point patterns, both the drone and aerial survey were more than 50% percent consistent with the ground survey, although the drone survey detected 28.57% more accurate mound spatial point patterns than the aerial survey. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Mngcele, Lizalise Sive Nqaba
- Date: 2022-12
- Subjects: Drone aircraft in remote sensing – Eastern Cape Karoo , Termites , Geographic information Systems – South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59555 , vital:62169
- Description: The Eastern Cape Karoo in South Africa has been earmarked for potential Shale Gas development, which has necessitated the understanding of existing ecosystems to be quantiĄed pre-development, in order to have a baseline against which the exploration can be monitored. Termite mounds as baseline mechanisms, are known to be sensitive to ecosystem disturbance and because of their abundance in the exploration zone, have been studied as indicator species. They are both a surface and subsurface phenomena which makes them an ideal baseline monitoring mechanism. Termite mound height, basal circumference and geospatial data was collected against natural and anthropogenic factors: elevation, vegetation, water, soil, geology, human settlements and roads. Mound distributions were observed across four study sites, and seven plots, using a DJI Phantom 4 Pro drone, an aerial and ground survey. Observed mound data on the drone and aerial survey was compared to that of the ground survey. Overall, the drone survey outperformed the aerial survey in recording accurate termite mound data. This was largely attributed to the scale of the study which gave the drone a competitive advantage. It allowed for drone data to be collected at 40 m altitude with an image resolution of 2-6 cm/pixel on each plot. In addition, drone detection accuracy was improved through the ability to generate digital surface models (DSMs) through point clouds and overlaying them with orthomosaics. Considering observed mound spatial point patterns, both the drone and aerial survey were more than 50% percent consistent with the ground survey, although the drone survey detected 28.57% more accurate mound spatial point patterns than the aerial survey. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Evaluation of the mesozooplankton functional diversity indices in Algoa Bay as proxies to assess the stability of the food chain leading to the African penguin (Spheniscus demersus)
- Authors: Rukuni, Praxedes Vimbai
- Date: 2022-12
- Subjects: Marine zooplankton --South Africa -- Algoa bay , Penguins -- South Africa -- Conservation , Fishes -- Predators of -- South Africa -- Algoa Bay
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59956 , vital:62698
- Description: Current unprecedented environmental changes threaten food web and ecosystem stability, which is particularly concerning in areas with vulnerable species such as the endangered African penguin Spheniscus demersus. In this study I adopted a holistic approach integrating many ecosystem levels to better understand African penguin behavioural ecology and food web stability. I investigated interplay between physico-chemical parameters and zooplankton functional diversity at various temporal and spatial scales in Algoa Bay. The study further investigated the applicability of zooplankton functional diversity (FD) in inferring African penguin food web stability by comparing the FD of zooplankton found in anchovies regurgitated from African penguins and the ones found in the Bay PELTER Stations. Gut contents of anchovies regurgitated from Bird Island and St Croix penguins were also evaluated using Frequency of Occurrence and Dominance methods and compared between colonies. Zooplankton FD in Algoa Bay varied over time but not at spatial scales with chlorophyll-a, Sea Surface Temperature (SST), turbidity and salinity being potential drivers of zooplankton FD. Chlorophyll-a and salinity were positively correlated with FD, meanwhile FD was inversely correlated to turbidity and SST. The study also observed minor differences in the physico-chemical parameters associated with African penguin foraging grounds, though different dietary preferences were found between the anchovies regurgitated from penguins from the two colonies. Anchovies regurgitated by penguins from Bird Island targeted large sized groups such as Decapods, meanwhile anchovies from the St Croix penguin colony targeted small sized Ostracods and Cirripedia. This study therefore, provides insight on the influence of fluctuations in physico-chemical parameters in shaping zooplankton communities in Algoa Bay. The study also emphasises anchovy dietary plasticity, switching from selective feeding to opportunistic feeding in instances of prey shortages which contributes to a stable African penguin food web in the face of climate change. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Rukuni, Praxedes Vimbai
- Date: 2022-12
- Subjects: Marine zooplankton --South Africa -- Algoa bay , Penguins -- South Africa -- Conservation , Fishes -- Predators of -- South Africa -- Algoa Bay
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59956 , vital:62698
- Description: Current unprecedented environmental changes threaten food web and ecosystem stability, which is particularly concerning in areas with vulnerable species such as the endangered African penguin Spheniscus demersus. In this study I adopted a holistic approach integrating many ecosystem levels to better understand African penguin behavioural ecology and food web stability. I investigated interplay between physico-chemical parameters and zooplankton functional diversity at various temporal and spatial scales in Algoa Bay. The study further investigated the applicability of zooplankton functional diversity (FD) in inferring African penguin food web stability by comparing the FD of zooplankton found in anchovies regurgitated from African penguins and the ones found in the Bay PELTER Stations. Gut contents of anchovies regurgitated from Bird Island and St Croix penguins were also evaluated using Frequency of Occurrence and Dominance methods and compared between colonies. Zooplankton FD in Algoa Bay varied over time but not at spatial scales with chlorophyll-a, Sea Surface Temperature (SST), turbidity and salinity being potential drivers of zooplankton FD. Chlorophyll-a and salinity were positively correlated with FD, meanwhile FD was inversely correlated to turbidity and SST. The study also observed minor differences in the physico-chemical parameters associated with African penguin foraging grounds, though different dietary preferences were found between the anchovies regurgitated from penguins from the two colonies. Anchovies regurgitated by penguins from Bird Island targeted large sized groups such as Decapods, meanwhile anchovies from the St Croix penguin colony targeted small sized Ostracods and Cirripedia. This study therefore, provides insight on the influence of fluctuations in physico-chemical parameters in shaping zooplankton communities in Algoa Bay. The study also emphasises anchovy dietary plasticity, switching from selective feeding to opportunistic feeding in instances of prey shortages which contributes to a stable African penguin food web in the face of climate change. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Grain size analysis, coastal hydrodynamics and erosion protection: a case study from Knysna and Plettenberg Bay, South Africa
- Authors: Pezisa, Ayabulela Raymond
- Date: 2022-12
- Subjects: Grain -- Analysis , Hydrodynamics , Shore protection
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27698 , vital:69394
- Description: The modern beach sands and Cretaceous Knysna Formation distributed along the coast of Plettenberg Bay and Knysna coast in the Western Cape Province of South Africa, have been examined and studied in the field outcrops and laborataries via grain-size analysis, XRD, SEM, EDX and microcope petrography analyses. This study looked into the coastal hydrodynamics and environment protection. The project aims to investigate the sediment distribution, grain-size variation, sedimentary structures, coast erosion and mitigation in the Plettenberg and Knysna coast to address environmental issues in the south coast of South Africa. The research will provide new insight onto coastal sedimentation, hydrodynamic condition, coastline erosion and the safety of the coastal environment and human property. The study will promote government attention on the sea level change, which caused flooding and environmental disaster along the south coastal area of South Africa. The rock sequence in the inland side of the study areas belongs to Cretaceous Knysna Formation, which comprises seven upward fining sequences. The stratigraphic sequence is underlain by the Table Mountain quartzite of the Cape Supergroup, and is overlain by Tertiary sediments and modern coastal dune sands. The Knysna Formation at the research area consists of massive conglomerate, sandstone and minor mudstone of mainly fluvial dominated sediments. The grain size analysis reveals that the modern fluvial channels at Plettenberg Bay and Knysna areas are of dominant coarse sands with minor silt and mud, which defines the sediments were deposited by moderate to high energy currents. Whilst the beach zones in Plettenberg Bay are predominated by fine to medium-grained marine sands. Grain-size analyses of beach sands show well-sorted, fine to coarse skewed in grain size distribution, indicating a relative lower to medium uniform energy condition during transportation and deposition. The bivariate plots of grain-size distribution demonstrate of the shallow agitated marine environment with the influence of tide and aeolian processes. Hydrodynamic condition in the beach area was more persistant and less variation compared to the river environment. The mineralogy and petrology studies revealed that in Plettenberg Bay and Knysna sediments are predominantly consisted of minerals quartz, feldspar, calcite, muscovite, aragonite, clay minerals, and salts (halite). Skeletal carbonate minerals (shell and coral fragments) are more than chemical precipitated carbonate minerals. The microtextures detected on the surface of the fluvial and marine sand grais involve V-shaped pits, upturn pits, dissolution pits and secondary mineral precipitation that were created by chemical and mechanical processes formed via sea-water dissolution, corrosion, and transport crashing. Whereas the boring holes and burrows created by activity of microorganisms boing into the surface of the grains. These microtextures of the river and beach sands exhibit a shallow marine and fluvial environments with medium to high energy conditions and active organic activities. Several sedimentary structures were detected in the coastal environments, including various types of ripple marks and dunes, burst bubble-hole, swash line, rill marks, rhomboid marks, burrows, boring and bioturbation, planar lamination and gravel pavement. In addition, sedimentary structures were also identified in the Cretaceous Knysna Formation such as air/water escape hole, convolute bedding, lenticular bedding, tabular cross-bedding and load cast. The sedimetnary structures closely linked with hydrodynamic conditions and therefore can be used as indicators for depositional environments. Flooding and erosion had become a coastal disaster that results in sediment redistribution throughout the coastal system and therefore caused landscape reform like coastal cliffs and sharpened dunes in erosive areas. Particularly, coastal hazards become more and more serious in recent years due to climate and sea leavel changes. Thus, to recognise coastal erosion and disaster and make a management strategy is of significant importance to compete against coastline retreat and to protect infrastructure and human safety in the coast area. The author had proposed a number of mitigation methods for environmental protection and for combating coastal erosion, including breakwaters, groins, jetties, vertical walls, rock armour, vegetation, boundary hardening, and revetment etc, which are the effective ways for protection of coast retreat, property damage and human safety. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Pezisa, Ayabulela Raymond
- Date: 2022-12
- Subjects: Grain -- Analysis , Hydrodynamics , Shore protection
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27698 , vital:69394
- Description: The modern beach sands and Cretaceous Knysna Formation distributed along the coast of Plettenberg Bay and Knysna coast in the Western Cape Province of South Africa, have been examined and studied in the field outcrops and laborataries via grain-size analysis, XRD, SEM, EDX and microcope petrography analyses. This study looked into the coastal hydrodynamics and environment protection. The project aims to investigate the sediment distribution, grain-size variation, sedimentary structures, coast erosion and mitigation in the Plettenberg and Knysna coast to address environmental issues in the south coast of South Africa. The research will provide new insight onto coastal sedimentation, hydrodynamic condition, coastline erosion and the safety of the coastal environment and human property. The study will promote government attention on the sea level change, which caused flooding and environmental disaster along the south coastal area of South Africa. The rock sequence in the inland side of the study areas belongs to Cretaceous Knysna Formation, which comprises seven upward fining sequences. The stratigraphic sequence is underlain by the Table Mountain quartzite of the Cape Supergroup, and is overlain by Tertiary sediments and modern coastal dune sands. The Knysna Formation at the research area consists of massive conglomerate, sandstone and minor mudstone of mainly fluvial dominated sediments. The grain size analysis reveals that the modern fluvial channels at Plettenberg Bay and Knysna areas are of dominant coarse sands with minor silt and mud, which defines the sediments were deposited by moderate to high energy currents. Whilst the beach zones in Plettenberg Bay are predominated by fine to medium-grained marine sands. Grain-size analyses of beach sands show well-sorted, fine to coarse skewed in grain size distribution, indicating a relative lower to medium uniform energy condition during transportation and deposition. The bivariate plots of grain-size distribution demonstrate of the shallow agitated marine environment with the influence of tide and aeolian processes. Hydrodynamic condition in the beach area was more persistant and less variation compared to the river environment. The mineralogy and petrology studies revealed that in Plettenberg Bay and Knysna sediments are predominantly consisted of minerals quartz, feldspar, calcite, muscovite, aragonite, clay minerals, and salts (halite). Skeletal carbonate minerals (shell and coral fragments) are more than chemical precipitated carbonate minerals. The microtextures detected on the surface of the fluvial and marine sand grais involve V-shaped pits, upturn pits, dissolution pits and secondary mineral precipitation that were created by chemical and mechanical processes formed via sea-water dissolution, corrosion, and transport crashing. Whereas the boring holes and burrows created by activity of microorganisms boing into the surface of the grains. These microtextures of the river and beach sands exhibit a shallow marine and fluvial environments with medium to high energy conditions and active organic activities. Several sedimentary structures were detected in the coastal environments, including various types of ripple marks and dunes, burst bubble-hole, swash line, rill marks, rhomboid marks, burrows, boring and bioturbation, planar lamination and gravel pavement. In addition, sedimentary structures were also identified in the Cretaceous Knysna Formation such as air/water escape hole, convolute bedding, lenticular bedding, tabular cross-bedding and load cast. The sedimetnary structures closely linked with hydrodynamic conditions and therefore can be used as indicators for depositional environments. Flooding and erosion had become a coastal disaster that results in sediment redistribution throughout the coastal system and therefore caused landscape reform like coastal cliffs and sharpened dunes in erosive areas. Particularly, coastal hazards become more and more serious in recent years due to climate and sea leavel changes. Thus, to recognise coastal erosion and disaster and make a management strategy is of significant importance to compete against coastline retreat and to protect infrastructure and human safety in the coast area. The author had proposed a number of mitigation methods for environmental protection and for combating coastal erosion, including breakwaters, groins, jetties, vertical walls, rock armour, vegetation, boundary hardening, and revetment etc, which are the effective ways for protection of coast retreat, property damage and human safety. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-12
Habitat use by Juvenile coastal fish in subtidal vegetated habitats of Algoa Bay;s shallow water seascape
- Authors: Mkhize,Thembani
- Date: 2022-12
- Subjects: Sailing ships -- South Africa -- Algoa Bay --History , Marine fishes -- Algoa Bay -- South Africa , Fish improvement habitat
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59788 , vital:62429
- Description: Structurally complex habitats such as seagrass, mangroves, and seaweed are important as nurseries in estuaries and nearshore marine environments. While numerous studies have focussed on structurally complex vegetated habitats in estuaries, few studies have focussed on vegetated nursery habitats (particularly seaweed) in coastal areas and their importance. The main aim of this project is to examine the nature of shallow water vegetated habitat (Zostera capensis seagrass and Plocamium corallorhiza macroalga) usage by juvenile fish in the Algoa Bay shallow water seascape (Swartkops Estuary and Flat Rocks nearshore subtidal reef). This aim was achieved by quantifying and comparing complexity of these two habitat-forming species, and the fish assemblages (relative abundance, richness, size structure and behaviour) across the two habitats. To measure and compare complexity of Z. capensis and P. corallorhiza, canopy height, density and leaf/blade width were sampled. In addition to these structural complexity indices, Fractal D (dimensionless complexity indices) was also quantified using Image software. Zostera capensis (1553.3 Indiv/m2 ) had a slightly higher mean density compared to P. corallorhiza (1303.7 Indiv/m2 ) but the difference was not significant. When sites (within each habitat) were compared, density did not show any significant differences between sites. Canopy height of Z. capensis (56.9 cm) was significantly higher compared to P. corallorhiza (16.6 cm), with no significant differences between sites. On the other hand, P. corallorhiza (0.9 cm) blades were significantly wider than Z. capensis (0.2 cm) leaves. Fractal D values followed the same trend as leaf/blade width with, with P. corallorhiza (1.8) having significantly higher Fractal D values than Z. capensis (1.5). The last two indices also had a positive relationship as Fractal D increased with increasing leaf/blade width. These results show that overall P. corallorhiza is more structurally complex than Z. capensis. Calibrated mini stereo underwater remote video systems (mini stereo-RUVs) were optimised in these two studied habitats to ensure they were suitable to measure and identify juvenile fishes. A pilot optimization study found that a minimum of five deployments and a minimum of 45 minutes filming duration is required to study fish assemblages in these two habitats. For comparison of fish assemblages and assessment of habitat use by fish, mini stereo-RUVs were deployed in both habitats (three sites per habitat) and were left to record for 60 minutes for a v total of five sampling occasions in seagrass and seven sampling occasions in macroalga between 7 September 2020 and 9 April 2021. Collected videos were analysed, with relative abundance (MaxN), richness and fish length extracted. Fish behaviour was also analysed and compared between habitats. Mean fish MaxN was slightly higher in Z. capensis (3.4) than in P. corallorhiza (2.9), although this result was not significant. Species diversity was significantly higher in P. corallorhiza as shown by both richness (Z. capensis = 11 and P. corallorhiza = 18) and the Shannon diversity index (Z. capensis = 1.3 and P. corallorhiza = 1.7). Both habitats were dominated by species from the family Sparidae, with six estuary-associated marine species common between the two habitats. Both Z. capensis and P. corallorhiza were dominated by juvenile fish, with more than 70 % of measured fish being juveniles. Fish length was not significantly different in the two habitats. Juvenile fish assemblages were significantly distinct between the two habitats (ANOSIM). In terms of habitat use, fish behaviour analysis showed that fish use both habitats as nurseries. There was no significant difference in fish behaviour in the two habitats and fish behaviours associated with higher levels of habitat use (slow meandering and feeding) were the most common behaviours in both habitats. Although not significant, feeding behaviour (also associated with a high degree of habitat use) was observed more in macroalga than in the seagrass habitat. Although none of the studied complexity indices could be related to abundance, both leaf/blade width and Fractal Dimension showed a positive relationship with the number of species recorded, while canopy height showed a strong negative relationship with the number of species. Overall, this study shows that Plocamium corallorhiza red macroalga in the shallow marine environment may be as important in shallow marine environments as Zostera capensis seagrass in estuaries as nursery habitats for marine fi , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Mkhize,Thembani
- Date: 2022-12
- Subjects: Sailing ships -- South Africa -- Algoa Bay --History , Marine fishes -- Algoa Bay -- South Africa , Fish improvement habitat
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59788 , vital:62429
- Description: Structurally complex habitats such as seagrass, mangroves, and seaweed are important as nurseries in estuaries and nearshore marine environments. While numerous studies have focussed on structurally complex vegetated habitats in estuaries, few studies have focussed on vegetated nursery habitats (particularly seaweed) in coastal areas and their importance. The main aim of this project is to examine the nature of shallow water vegetated habitat (Zostera capensis seagrass and Plocamium corallorhiza macroalga) usage by juvenile fish in the Algoa Bay shallow water seascape (Swartkops Estuary and Flat Rocks nearshore subtidal reef). This aim was achieved by quantifying and comparing complexity of these two habitat-forming species, and the fish assemblages (relative abundance, richness, size structure and behaviour) across the two habitats. To measure and compare complexity of Z. capensis and P. corallorhiza, canopy height, density and leaf/blade width were sampled. In addition to these structural complexity indices, Fractal D (dimensionless complexity indices) was also quantified using Image software. Zostera capensis (1553.3 Indiv/m2 ) had a slightly higher mean density compared to P. corallorhiza (1303.7 Indiv/m2 ) but the difference was not significant. When sites (within each habitat) were compared, density did not show any significant differences between sites. Canopy height of Z. capensis (56.9 cm) was significantly higher compared to P. corallorhiza (16.6 cm), with no significant differences between sites. On the other hand, P. corallorhiza (0.9 cm) blades were significantly wider than Z. capensis (0.2 cm) leaves. Fractal D values followed the same trend as leaf/blade width with, with P. corallorhiza (1.8) having significantly higher Fractal D values than Z. capensis (1.5). The last two indices also had a positive relationship as Fractal D increased with increasing leaf/blade width. These results show that overall P. corallorhiza is more structurally complex than Z. capensis. Calibrated mini stereo underwater remote video systems (mini stereo-RUVs) were optimised in these two studied habitats to ensure they were suitable to measure and identify juvenile fishes. A pilot optimization study found that a minimum of five deployments and a minimum of 45 minutes filming duration is required to study fish assemblages in these two habitats. For comparison of fish assemblages and assessment of habitat use by fish, mini stereo-RUVs were deployed in both habitats (three sites per habitat) and were left to record for 60 minutes for a v total of five sampling occasions in seagrass and seven sampling occasions in macroalga between 7 September 2020 and 9 April 2021. Collected videos were analysed, with relative abundance (MaxN), richness and fish length extracted. Fish behaviour was also analysed and compared between habitats. Mean fish MaxN was slightly higher in Z. capensis (3.4) than in P. corallorhiza (2.9), although this result was not significant. Species diversity was significantly higher in P. corallorhiza as shown by both richness (Z. capensis = 11 and P. corallorhiza = 18) and the Shannon diversity index (Z. capensis = 1.3 and P. corallorhiza = 1.7). Both habitats were dominated by species from the family Sparidae, with six estuary-associated marine species common between the two habitats. Both Z. capensis and P. corallorhiza were dominated by juvenile fish, with more than 70 % of measured fish being juveniles. Fish length was not significantly different in the two habitats. Juvenile fish assemblages were significantly distinct between the two habitats (ANOSIM). In terms of habitat use, fish behaviour analysis showed that fish use both habitats as nurseries. There was no significant difference in fish behaviour in the two habitats and fish behaviours associated with higher levels of habitat use (slow meandering and feeding) were the most common behaviours in both habitats. Although not significant, feeding behaviour (also associated with a high degree of habitat use) was observed more in macroalga than in the seagrass habitat. Although none of the studied complexity indices could be related to abundance, both leaf/blade width and Fractal Dimension showed a positive relationship with the number of species recorded, while canopy height showed a strong negative relationship with the number of species. Overall, this study shows that Plocamium corallorhiza red macroalga in the shallow marine environment may be as important in shallow marine environments as Zostera capensis seagrass in estuaries as nursery habitats for marine fi , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Investigation of thermal and electrical characteristics of crystalline silicon photovoltaic modules under varying operational conditions
- Authors: Vumbugwa, Monphias
- Date: 2022-12
- Subjects: Photovoltaic power generation -- South Africa , Silicon crystals -- South Africa , Solar cells
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60014 , vital:62733
- Description: Solar energy has become an attractive and environmentally mindful method in electrical power generation as it contributes significantly to meeting the high demand for the power needed for socio and economic developments. The rise in deployment of Photovoltaic (PV) facilities with large capacity creates the need for accurate and reliable PV inspection techniques for optimum performance, the longevity of PV modules and quick return on PV investment. The performance of PV modules in the field is often monitored through several inspection methods that require a rapid throughput such as Thermal Infrared (TIR) imaging and current-voltage (I-V) measurements. Unmanned Aerial Vehicle (UAV) based TIR imaging is widely applied in large PV plants since it is cost-effective and is usually conducted in-situ while the plant is operating at irradiance levels above 600 W.m-2 . One of the outcomes of the interpretations of TIR images is an attempt to quantify the energy loss in PV plants associated with the abnormal thermal signatures identified on TIR images. No standard procedure has yet outlined the quantification of energy loss related to TIR images of underperforming modules since the interpretation of TIR images remains a challenge. PV modules operate under dynamic operating conditions which can influence the results and interpretation of thermal and electrical characterisation measurements. Dynamic operation conditions refer to any disorders in the operation of the modules and cells which cause a change in the current and voltage characteristics of the PV source. These dynamic operation conditions include; changesin load conditions, irradiance, soiling and shading levels. The tests were done under steady state conditions. Although measurements are generally done while the operating conditions are as steady as possible, some changes in conditions have a profound effect on thermal and electrical measurements. In this study, these effects and some of the changes in conditions that cause them were studied. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Vumbugwa, Monphias
- Date: 2022-12
- Subjects: Photovoltaic power generation -- South Africa , Silicon crystals -- South Africa , Solar cells
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60014 , vital:62733
- Description: Solar energy has become an attractive and environmentally mindful method in electrical power generation as it contributes significantly to meeting the high demand for the power needed for socio and economic developments. The rise in deployment of Photovoltaic (PV) facilities with large capacity creates the need for accurate and reliable PV inspection techniques for optimum performance, the longevity of PV modules and quick return on PV investment. The performance of PV modules in the field is often monitored through several inspection methods that require a rapid throughput such as Thermal Infrared (TIR) imaging and current-voltage (I-V) measurements. Unmanned Aerial Vehicle (UAV) based TIR imaging is widely applied in large PV plants since it is cost-effective and is usually conducted in-situ while the plant is operating at irradiance levels above 600 W.m-2 . One of the outcomes of the interpretations of TIR images is an attempt to quantify the energy loss in PV plants associated with the abnormal thermal signatures identified on TIR images. No standard procedure has yet outlined the quantification of energy loss related to TIR images of underperforming modules since the interpretation of TIR images remains a challenge. PV modules operate under dynamic operating conditions which can influence the results and interpretation of thermal and electrical characterisation measurements. Dynamic operation conditions refer to any disorders in the operation of the modules and cells which cause a change in the current and voltage characteristics of the PV source. These dynamic operation conditions include; changesin load conditions, irradiance, soiling and shading levels. The tests were done under steady state conditions. Although measurements are generally done while the operating conditions are as steady as possible, some changes in conditions have a profound effect on thermal and electrical measurements. In this study, these effects and some of the changes in conditions that cause them were studied. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-12
Mesozooplankton and particle dynamics in Algoa Bay, South Africa
- Engelbrecht, Melindi Frances
- Authors: Engelbrecht, Melindi Frances
- Date: 2022-12
- Subjects: Marine zooplankton – Algoa bay -- South Africa , Estuarine ecology , Zooplankton –Ecology --South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59544 , vital:62157
- Description: Coastal ecosystems provide society with important ecosystem services: climate regulation, biogeochemical nutrient and waste cycling, food security, shoreline protection, tourism, and recreational support. Increased anthropogenic pressure on coastal ecosystems and changing environmental variables ultimately affect the provision of ecosystem services. Mesozooplankton are key trophic species and biological indicators of change within the marine environment and provide sound predictions of ecosystem responses to a changing climate due to their short life cycles and physiology linked to temperature. Algoa Bay has been the subject of extensive research and monitoring and encompasses a marine protected area (Addo Elephant National Park MPA). The Underwater Vision Profiler 5 (UVP5) was utilised with conventional sampling techniques of the PELTER monitoring program (i.e., Bongo nets) to investigate mesozooplankton (200 – 2000 µm) and particle (> 100 µm) dynamics within the dynamic coastal ecosystem of Algoa Bay, located within warmtemperate South Africa, in spring 2020 and summer 2021. This study revealed seasonal shifts in mesozooplankton taxa succession from spring herbivorous/omnivorous, dominated by copepods, to summer omnivorous/carnivorous mesozooplankton, dominated by copepods, Noctiluca sp., Cladocera, doliolids, salps and siphonophores. The mesozooplankton integrated abundance (mean ± standard error) increased from spring to summer, with 101 ± 26 (min. – max.: 18 – 200) x 103 ind m¯ 2 and 422 ± 80 (min. – max.: 37 – 1056) x 103 ind m¯ 2 , respectively. In summer, mesozooplankton composition was affected by the passage of a Natal Pulse, identified from satellite-derived sea level anomaly data. This study also provided the first vertical profiles of copepod distributions and suspended particles in Algoa Bay, with a peak of small particle (< 1 mm ESD) biomass close to the bottom and often, but not systematically, higher copepod abundances above the thermocline. The results presented herein are expected to contribute to the understanding of the coastal pelagic ecosystem in Algoa Bay in response to environmental perturbations , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Engelbrecht, Melindi Frances
- Date: 2022-12
- Subjects: Marine zooplankton – Algoa bay -- South Africa , Estuarine ecology , Zooplankton –Ecology --South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59544 , vital:62157
- Description: Coastal ecosystems provide society with important ecosystem services: climate regulation, biogeochemical nutrient and waste cycling, food security, shoreline protection, tourism, and recreational support. Increased anthropogenic pressure on coastal ecosystems and changing environmental variables ultimately affect the provision of ecosystem services. Mesozooplankton are key trophic species and biological indicators of change within the marine environment and provide sound predictions of ecosystem responses to a changing climate due to their short life cycles and physiology linked to temperature. Algoa Bay has been the subject of extensive research and monitoring and encompasses a marine protected area (Addo Elephant National Park MPA). The Underwater Vision Profiler 5 (UVP5) was utilised with conventional sampling techniques of the PELTER monitoring program (i.e., Bongo nets) to investigate mesozooplankton (200 – 2000 µm) and particle (> 100 µm) dynamics within the dynamic coastal ecosystem of Algoa Bay, located within warmtemperate South Africa, in spring 2020 and summer 2021. This study revealed seasonal shifts in mesozooplankton taxa succession from spring herbivorous/omnivorous, dominated by copepods, to summer omnivorous/carnivorous mesozooplankton, dominated by copepods, Noctiluca sp., Cladocera, doliolids, salps and siphonophores. The mesozooplankton integrated abundance (mean ± standard error) increased from spring to summer, with 101 ± 26 (min. – max.: 18 – 200) x 103 ind m¯ 2 and 422 ± 80 (min. – max.: 37 – 1056) x 103 ind m¯ 2 , respectively. In summer, mesozooplankton composition was affected by the passage of a Natal Pulse, identified from satellite-derived sea level anomaly data. This study also provided the first vertical profiles of copepod distributions and suspended particles in Algoa Bay, with a peak of small particle (< 1 mm ESD) biomass close to the bottom and often, but not systematically, higher copepod abundances above the thermocline. The results presented herein are expected to contribute to the understanding of the coastal pelagic ecosystem in Algoa Bay in response to environmental perturbations , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Moult and energetics in three species from the Euplectes genus representing a gradient of elaborate plumage ornamentation
- Authors: Webb, Stacey Leigh
- Date: 2022-12
- Subjects: Sexual selection in animals – South Africa , Bird watching -- Africa, Southern , Plumage
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60026 , vital:62734
- Description: Elaborate plumage ornamentation in birds has fascinated scientists since the 1800s. The evolution and persistence of elaborate and costly ornamentation seemed to be in opposition to the theory of natural selection. However, over the years research has revealed the role and functional significance of elaborate plumage ornamentation in sexual selection. Recent studies have shown that the energetic costs associated with moulting into new plumages are higher than maintenance costs, but these costs have not been quantified for species that exhibit elaborate breeding plumage ornamentation for sexual selection. In addition, for these sexually selected ornamental traits (signals) to have evolved and be maintained, there must be some aspect of individual quality that they convey to the receiver. Despite a large body of literature on sexual selection, honest signalling and ornamental plumage in birds, the physiological correlates of honest signalling during sexual selection and the messages these signals convey to the receivers are poorly understood. In this study, I investigated four aspects related to the honesty of the sexual selection signal. These were (i) seasonal variation in standardised resting metabolic rates of breeding and non-breeding birds, (ii) moult phenology, (iii) physiological parameters linked to honest signalling, and (iv) the energetic costs of production and maintenance of elaborate plumage ornamentation using three species from the Euplectes genus as model species. The three species selected, the red-collared widowbird (Euplectes ardens), fan-tailed widowbird (Euplectes axillaris) and the southern red bishop (Euplectes orix) represent a gradient of plumage elaboration and although the receivers of the sexual selection signals are known for these three species, the energetic cost of the signals and the underlying message the signals convey remain unknown. I measured seasonal variation in resting metabolic rate (RMR), body mass (Mb), thermoneutral zone (TNZ) and body temperature (Tb) over the course of two years in the three selected Euplectes species (E. ardens, E. axillaris and E. orix; chapter 2). My results showed no significant effect of season on RMR (except in E. orix females) suggesting that in these species the metabolic costs in summer (associated with breeding season) are comparable to the metabolic costs associated with thermoregulation during winter. Contrary to my prediction that metabolic costs would increase along a gradient of increasing tail length (due to the energetic costs Webb V associated with elaborate plumage ornamentation), I found no significant effect of species. The lack of a significant result indicates that once the initial investment in plumage is complete, other predictor variables play a role (in this case body mass). , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Webb, Stacey Leigh
- Date: 2022-12
- Subjects: Sexual selection in animals – South Africa , Bird watching -- Africa, Southern , Plumage
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60026 , vital:62734
- Description: Elaborate plumage ornamentation in birds has fascinated scientists since the 1800s. The evolution and persistence of elaborate and costly ornamentation seemed to be in opposition to the theory of natural selection. However, over the years research has revealed the role and functional significance of elaborate plumage ornamentation in sexual selection. Recent studies have shown that the energetic costs associated with moulting into new plumages are higher than maintenance costs, but these costs have not been quantified for species that exhibit elaborate breeding plumage ornamentation for sexual selection. In addition, for these sexually selected ornamental traits (signals) to have evolved and be maintained, there must be some aspect of individual quality that they convey to the receiver. Despite a large body of literature on sexual selection, honest signalling and ornamental plumage in birds, the physiological correlates of honest signalling during sexual selection and the messages these signals convey to the receivers are poorly understood. In this study, I investigated four aspects related to the honesty of the sexual selection signal. These were (i) seasonal variation in standardised resting metabolic rates of breeding and non-breeding birds, (ii) moult phenology, (iii) physiological parameters linked to honest signalling, and (iv) the energetic costs of production and maintenance of elaborate plumage ornamentation using three species from the Euplectes genus as model species. The three species selected, the red-collared widowbird (Euplectes ardens), fan-tailed widowbird (Euplectes axillaris) and the southern red bishop (Euplectes orix) represent a gradient of plumage elaboration and although the receivers of the sexual selection signals are known for these three species, the energetic cost of the signals and the underlying message the signals convey remain unknown. I measured seasonal variation in resting metabolic rate (RMR), body mass (Mb), thermoneutral zone (TNZ) and body temperature (Tb) over the course of two years in the three selected Euplectes species (E. ardens, E. axillaris and E. orix; chapter 2). My results showed no significant effect of season on RMR (except in E. orix females) suggesting that in these species the metabolic costs in summer (associated with breeding season) are comparable to the metabolic costs associated with thermoregulation during winter. Contrary to my prediction that metabolic costs would increase along a gradient of increasing tail length (due to the energetic costs Webb V associated with elaborate plumage ornamentation), I found no significant effect of species. The lack of a significant result indicates that once the initial investment in plumage is complete, other predictor variables play a role (in this case body mass). , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Psychologists’ perceptions of the growth and change promoting factors in psychotherapy within a culturally diverse South Africa
- Authors: Heyneke, Wilmie
- Date: 2022-12
- Subjects: Psychotherapy -- South Africa , therapeutic alliance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/60155 , vital:63207
- Description: The therapeutic relationship established between a psychologist and a client is considered one of the main factors determining successful psychotherapy outcomes. While this may be the case, there remain inconsistencies in the literature and debate regarding its influence, especially when contextual factors such as diverse beliefs, may influence the therapeutic relationship. Furthermore, there is a scarcity of information focusing on psychologists’ experiences working within the culturally diverse South African context. This study aimed to better understand, from a psychologist’s perspective, the growth and change promoting factors they feel are influencing successful therapeutic outcomes within the South African context. This was pursued recognising that the diverse belief systems in South Africa, which do not always adhere to biomedical conceptualisations of health and illness, may influence the therapeutic interaction. This study explored the following research question: What are the key factors that promote growth and change in individual psychotherapy within the diverse South African context? Drawing on a qualitative approach, an explorative descriptive research design was chosen as it enabled the researcher to explore the perceptions of the participants on the given topic. The sampling technique that was employed was non-probability purposive sampling and psychologists registered with the Health Professionals Council of South Africa formed part of the sample. In-depth online interviewing was employed as the data collection tool, using online platforms like Microsoft Teams and Zoom. Data were analysed using Braun and Clarke’s thematic analysis guidelines and themes that were identified was reported. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Heyneke, Wilmie
- Date: 2022-12
- Subjects: Psychotherapy -- South Africa , therapeutic alliance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/60155 , vital:63207
- Description: The therapeutic relationship established between a psychologist and a client is considered one of the main factors determining successful psychotherapy outcomes. While this may be the case, there remain inconsistencies in the literature and debate regarding its influence, especially when contextual factors such as diverse beliefs, may influence the therapeutic relationship. Furthermore, there is a scarcity of information focusing on psychologists’ experiences working within the culturally diverse South African context. This study aimed to better understand, from a psychologist’s perspective, the growth and change promoting factors they feel are influencing successful therapeutic outcomes within the South African context. This was pursued recognising that the diverse belief systems in South Africa, which do not always adhere to biomedical conceptualisations of health and illness, may influence the therapeutic interaction. This study explored the following research question: What are the key factors that promote growth and change in individual psychotherapy within the diverse South African context? Drawing on a qualitative approach, an explorative descriptive research design was chosen as it enabled the researcher to explore the perceptions of the participants on the given topic. The sampling technique that was employed was non-probability purposive sampling and psychologists registered with the Health Professionals Council of South Africa formed part of the sample. In-depth online interviewing was employed as the data collection tool, using online platforms like Microsoft Teams and Zoom. Data were analysed using Braun and Clarke’s thematic analysis guidelines and themes that were identified was reported. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-12