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Supporting social learning and knowledge management withing the ecological infrastructure for water security project

An integrative approach to understanding vulnerability of an alpine range-restricted bird to climate warming

  • Authors: Oswald, Krista Natasha
  • Date: 2020
  • Subjects: Passeriformes -- South Africa -- Western Cape , Passeriformes -- Physiology -- South Africa -- Western Cape , Passeriformes -- Behavior -- Climatic factors -- South Africa -- Western Cape , Passeriformes -- Reproduction -- Climatic factors -- South Africa -- Western Cape , Passeriformes -- Dispersal -- South Africa -- Western Cape , Passeriformes -- Food -- South Africa -- Western Cape , Passeriformes -- Nests-- South Africa -- Western Cape , Blue Hill Nature Reserve , Cape Rockjumper -- Climatic factors , Chaetops frenatus
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/148517 , vital:38746
  • Description: Understanding species' vulnerability to climate change requires an integrative ecological approach involving, at minimum, physiology, behaviour, reproductive success, and limitations on dispersal. In this thesis I determined potential negative effects of increasing temperatures on behaviour, reproduction, and ability to disperse in an alpine-restricted bird, the Cape Rockjumper Chaetops frenatus ("Rockjumper"). Here I provide a comprehensive ecological set of data for understanding the link between Rockjumper population declines and warming habitats. I tested whether Rockjumper microsite-use at high temperatures resulted in decreased time spent on important behaviours, such as foraging. I found Rockjumpers made increased use of rock-shade as air temperature increased and so spent less time panting, but birds in rock-shade foraged less. Birds may be constrained to foraging in sun at high temperatures to sustain energy or water requirements, despite risks of high thermal load, or else face lost foraging opportunities by remaining in rock-shade. I determined if adult nest attendance and causes of nest failure were related to high temperatures. I filmed nests over two breeding seasons to examine temperature-effects on adult time in nests, provisioning rate, and resultant nestling daily mass gain. The only temperature effect I found was decreased percent daily change in body mass for older nestlings at hotter temperatures. I also examined causes of nest failure over three breeding seasons in relation to nest concealment and habitat openness by observing failure/success. Nests in more open territories (i.e. early post-fire habitat) had greater success, and the main cause of predation came from Boomslang Dispholydus typus. Importantly, the probability of Boomslang predation increased significantly at hotter temperatures. These findings show there may be direct negative effects of increasing temperatures on reproductive success and population recruitment, and so hotter temperature during the breeding season may be at least partly responsible for observed population declines. Lastly, I examined genetic structure of populations across mountain ranges separated from one another by lowland habitat unsuitable for Rockjumpers. I predicted I would find little evidence for dispersal between mountain ranges separated by unsuitable lowland habitat, but instead found Rockjumpers show little evidence for inbreeding. I also found evidence for a past bottleneck event or founder effect, and little overall genetic diversity (possibly as their specialized niche exerts selective pressure). Low diversity may limit Rockjumpers' ability to adapt to a changing environment. Adult physiological and behavioural thresholds to increasing temperatures are often used to create predictions of climate change effects. My past physiological research and current behavioural research suggest no particularly strong evidence that temperature-related population declines are driven by poor physiological capacity to tolerate heat or negative behaviour trade-offs. Instead, my current research shows that understanding negative effects of increasing temperatures may require a more in-depth approach involving investigation of fine-scale ecological interactions. No single one of my chapters provides the insight necessary for understanding Rockjumper population declines at warming temperatures. Instead, I show how an integrative approach may be necessary for assessing species' vulnerability to climate change by examining multiple ecological aspects of a single sentinel species, using an alpine species with a narrow thermal range and highly specialized habitat niche.
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  • Date Issued: 2020

How do urban dwellers identify with features within urban green spaces in the Eastern Cape?

  • Authors: Manyani, Amanda
  • Date: 2019
  • Subjects: Land use, Urban -- South Africa , Greenbelts -- South Africa , City planning -- South Africa
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/95596 , vital:31174
  • Description: Public urban green spaces contain natural and artificial features which play crucial roles in supporting urban social-ecological systems, a fact now recognized globally. The various natural and artificial features contained in public urban green spaces are said to be key contributors to the quality of life and well-being of urban dwellers. Nevertheless, this has been largely ignored in urban design in South Africa, especially in the poorer township and Reconstruction Development Program (RDP) areas. At the individual household and community levels within the poorer communities, the provision of green spaces and trees, as well as recreation facilities, is well below world standards, and much less than what is available in the more affluent areas of South African towns. Additionally, most research on the links between nature and human well-being in urban contexts comes from developed world contexts which adopt a westernized view of the relationship. Yet, in many societies of the Global South, including South Africa, worldviews and experiences of nature in green spaces and use of other recreational features takes on different meanings to those of the Global North. To show these differences, a combination of methods was used in this study, different types of green spaces were assessed and evaluated by structured observations so as to record the features present within the spaces. A survey of 360 households was conducted by targeting green space users and households within 100 metres from a green space. Results indicated that, across all the green space types, formal green spaces had a low cover of shrubs, trees and herbs whilst having high lawn cover. Furthermore, vegetation had poor rating across all the green spaces since the vegetation was either overgrown herbs, dense thickets of shrubs and mostly alien trees that were either diseased or forked. Similar to the disparity in the composition and structure of vegetation within the green spaces, there was a wide variability in the composition of recreational features and amenities across the green spaces. The formal green spaces had the most amenities like play equipment, shelter and seating. Informal green spaces and commonages had little or no recreational features available. The attributes of these spaces therefore influenced the reasons for visiting as more than 90 % of the respondents simply used the spaces for transit. With regards to attitudes and preferences towards particular features, they were emerging sense of strong negative feelings towards natural features. Most respondents emphasized the need for green spaces that are well laid out with maintained lawns, recreational facilities and open vegetation. Thus, the current design and available features within the studied urban green spaces do not meet local needs and aspirations and thus do not contribute to better well-being and quality of life as much as they could. Specifically, the various health benefits linked with being in contact with nature in the public green spaces were not evident in this study. The South African specific context in green space use, perception and people’s preferences is thus crucial for urban planning and sustainability.
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  • Date Issued: 2019

Post-release evaluation of Megamelus scutellaris Berg. (hemiptera: delphacidae): a biological control agent of water hyacinth Eichhornia crassipes (Mart.) Solms-Laub (Pontederiaceae) in South Africa

  • Authors: Miller, Benjamin Erich
  • Date: 2019
  • Subjects: Megamelus scutellaris Berg. , Delphacidae , Noxious weeds -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Water hyacinth -- Biological control -- South Africa , Biological pest control agents
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/92330 , vital:30710
  • Description: Water hyacinth, Eichhornia crassipes (Mart.) Solms-Laub. (Pontederiaceae) is a free-floating aquatic macrophyte from South America that was introduced to South Africa in the 1900s for its attractive ornamental flowers. The plant was classified as a serious invader in the country in the 1970s, eventually becoming the worst invasive aquatic plant in South Africa. Biological control is widely regarded as the most effective method of managing water hyacinth, as it is ecologically safe, cost-effective, and self-sustaining. To date, nine biological control agents have been released in South Africa against water hyacinth, including eight arthropods and a pathogen. Due to the cumulative effects of highly eutrophic waterbodies, which mitigate the damage caused by biological control, and the cold winters which inhibit the rate of biological control agent population build up, South Africa currently has more biological control agents released on water hyacinth than anywhere else in the world. The need for a cold-tolerant agent that can reproduce and develop quickly, while still being damaging to water hyacinth in eutrophic systems, led to the introduction of the most recently released water hyacinth biological control agent, the planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae), which was initially collected from Argentina. This thesis formed the first post-release evaluation of M. scutellaris since its release in South Africa in 2013. It included a greenhouse experiment to measure the agent’s feeding damage in relation to different nutrient levels and stocking rates, as well as a field component to evaluate both the post-winter recovery of M. scutellaris, and a nationwide survey to measure the establishment of the agent around the country in relation to climate, water quality, and plant health. In the greenhouse experiment, the feeding damage was quantified using measurements of plant growth parameters and chlorophyll fluorometry. It was found that, like other biological control agents of water hyacinth, M. scutellaris was most damaging when released in high numbers on plants grown at medium nutrient levels, and less effective on plants grown at elevated nutrient levels. A water hyacinth infestation on the Kubusi River was selected for the evaluation of the post-winter recovery of M. scutellaris. The Kubusi River is both the first site where M. scutellaris was released, and the coldest site where water hyacinth biological control agents have established successfully in South Africa. Monthly visits tracking seasonal plant health characteristics and agent population densities indicated that the populations of M. scutellaris were impacted most significantly by the season. Low temperatures led to the water hyacinth plants being of poor quality during the winter, which had a subsequent negative effect on the agent populations. The agents could only fully recover by late summer, which meant that the plants were without any significant biological control through the initial phases of the growing season, when they were most vulnerable, and a significant lag-phase occurred between the recovery of the plants and the recovery of the agent population after the winter bottleneck. A survey of all sites where M. scutellaris had been released in South Africa yielded 16 sites where the agents had successfully established, having survived at least one full winter. Among these sites were four sites where the agents were found without them having been released, indicating that they can disperse unaided to new sites. The temperature was a major factor responsible for the success or failure of establishment, with very few agents surviving in the hot areas of South Africa or in areas with a high frost incidence. The density of M. scutellaris was higher in nutrient-rich water, and on plants with more leaves, suggesting that the quality of the plants also contributed to establishment. The results of this thesis showed that M. scutellaris is able to establish successfully in South Africa, and that the agents are capable of causing significant damage to water hyacinth, making it a promising addition to the biological control programme. Novel methods of measuring subtle insect feeding damage in plants and quantifying agent populations are also discussed, along with suggestions for the future implementation of M. scutellaris in South Africa.
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  • Date Issued: 2019

Repatriating Xhosa music recordings archived at the International Library of African Music (ILAM) and reviving interest in traditional Xhosa music among the youth in Grahamstown

  • Authors: Madiba, Elijah Moleseng
  • Date: 2019
  • Subjects: International Library of African Music , Xhosa (African people) -- Music , Sound recordings in ethnomusicology -- South Africa , Ethnomusicology -- South Africa -- Makhanda , Cultural property -- Repatriation -- South Africa -- Makhanda , Rap musicians -- South Africa -- Makhanda
  • Language: English
  • Type: text , Thesis , Masters , MMus
  • Identifier: http://hdl.handle.net/10962/76599 , vital:30611
  • Description: This research looks at the feasibility of using repatriation as a tool for the revitalisation of indigenous music within a contemporary South African musical context. Using tracks from the International Library of African Music (ILAM), this investigation presents isiXhosa traditional and indigenous music to a group of musicians from a hip-hop background that would never have had access to this type of music before. The thesis then traces their creative use of the music within their own genres. Speaking to the legacy of the Hugh Tracey collection at ILAM and criticisms that have surfaced, this research also attempts to validate the efforts made by Hugh Tracey in collecting and documenting African music. Themes ranging from understanding the term “tradition” are addressed, as well as other technical terms in the vernacular while also exploring and analysing the results of the repatriation project. Practical issues regarding the sampling of indigenous music were interrogated carefully due to the fact that the complexity of African music was foreign to most of the participants. Their familiarity with the music, or lack thereof, either motivated or ended the musicians’ participation in the research project. An in-depth analysis of the results of the musicians’ interaction with the music is presented where this study finds, at the heart of this research, that the musicians performed as agents who easily took to revitalising the music.
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  • Date Issued: 2019

Shifting white SADF veteran identities from apartheid to contemporary South Africa

  • Authors: Weich, Francois
  • Date: 2019
  • Subjects: South Africa -- History -- 1961-1994 , Angola -- History -- South African Incursions, 1978-1990 -- Veterans , South Africa -- History, Military -- 1961- , Veterans -- South Africa -- Personal narratives , South Africa -- Armed forces , South Africa -- Politics and government -- 1961-1978 , South Africa -- Politics and government -- 1978-1989 , South Africa. South African Defence Force
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/76106 , vital:30504
  • Description: The ideologies and structures of the apartheid state have received extensive academic attention, but the legacies of the militarisation of white South African men – a group that exists at a unique intersection of apartheid privilege and exploitation – have not been sufficiently addressed. Even as beneficiaries of apartheid, white men were militarised through structures of coercion and the mobilisation of identity constructions that resulted in the widespread submission to conscription and support for apartheid militarism. This thesis explores the relationship between those militarised identities and the historical processes of apartheid through a consideration of a broad range of white SADF veteran narratives from the Missing Voices Oral History Project archive. This consideration of the role of identity mobilisation in apartheid can shed light on the effect of historical processes of militarisation on white men in South Africa, as well as address the persistence of values and behaviours that may present barriers to the social transformation of South Africa towards a true constitutional democracy. The thesis explores identity in SADF veteran narratives through the application of social constructionism in order to determine the effect of coercive structures and identity mobilisation on individuals, and to gauge the persistence militarised identities after the social and political structures underpinning them had become defunct. The identity content of the narratives is contextualised in relation to structures of coercion employed by the apartheid state and the SADF alongside a consideration of the effect of political transition on veterans. The legacy of the historical environment and the impact of political transition on SADF veterans’ constructed identities is investigated in relation to these veterans’ own visions of their roles in post-apartheid South Africa. Therefore, this thesis endeavours to contribute to the expansion of the field of historical and identity study by considering the construction and renegotiation of military identities that maintained, benefited from, and were exploited by the apartheid state.
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  • Date Issued: 2019

The remote sensing of fires and their effects on soil properties in the uKhahlamba Drakensberg Park

  • Authors: Moore, Natasha Jade
  • Date: 2019
  • Subjects: Remote sensing -- South Africa -- KwaZulu-Natal , Soil ecology -- South Africa -- KwaZulu-Natal , Grassland fires -- South Africa -- KwaZulu-Natal , Grassland fires -- Remote sensing -- South Africa -- KwaZulu-Natal , Soils -- Effect of fires on -- South Africa -- KwaZulu-Natal , uKhalamba Drakensberg Park (South Africa)
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/94400 , vital:31042
  • Description: Fires are a common and natural occurrence globally and specifically on the African continent. The Drakensberg Mountains are home to southern Africa’s high-altitude fire-climax grasslands, where fire is the dominant management tool. Fire is used to maintain the grasslands in the uKhahlamba Drakensberg Park (UDP) World Heritage Site, located on the eastern escarpment of the KwaZulu-Natal Drakensberg. This study aimed to investigate the spatial and temporal frequency of fires using remote sensing, and to investigate the effect of fire frequency on soil properties in the UDP. Remote sensing offers a set of supportive tools for the management of this sensitive vegetation and specifically to assess the frequency and spatial extent of fires. Field assessments can then be used to assess the impact of fires. Remotely sensed data were used to determine fire frequency and the spatial extent of fires in the UDP. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) active fire detection point data were processed to investigate the temporal resolution of fires. Landsat 5 and 8 imagery were utilised for conducting Normalised Burn Ratios (NBR) to determine the spatial extent of the burn scars of fires. The results from the remotely sensed data were used to select study sites for accessing the effects of fire frequency on soil properties. The remote sensing results showed the main fire season in the UDP was from May to October, and annual burn scars from the available Landsat data for 1998 to 2017 ranged from 22.5% to 57.67% of the UDP. Remote sensing was shown to be an effective tool for monitoring fires in the UDP, with a combination of satellite data producing the best results. Soil properties were highly varied across the UDP. Environmental factors were shown to have a more significant influence on soil properties than fire frequency. This study highlighted the complex nature and diversity of fires and soils across the UDP.
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  • Date Issued: 2019

Developing a citizen technician based approach to suspended sediment monitoring in the Tsitsa River catchment, Eastern Cape, South Africa

  • Authors: Bannatyne, Laura Joan
  • Date: 2018
  • Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/62593 , vital:28211
  • Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
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  • Date Issued: 2018

The changing face of Rhodes University: exploring aspects of visuality, sexuality and protest between the apartheid and postapartheid periods

The teaching practice component of initial teacher education: a social justice approach

  • Authors: Long, Kelly Ann
  • Date: 2018
  • Subjects: Educational change -- South Africa , Teachers -- Training of -- South Africa , Education -- South Africa -- History , Education – South Africa -- Evaluation , Education -- Standards -- South Africa , Teacher effectiveness -- South Africa , Social justice and education , Education -- Study and teaching (Higher) -- South Africa
  • Language: English
  • Type: text , Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10962/60200 , vital:27746
  • Description: Research asserts that learner performance in South African schools is in a state of crisis. While many more learners’ post-1994 in South Africa have physical access to education, very few have epistemological access. The quality of the education learners receive is polarised along socio economic lines. This crisis has its roots in the legacy of colonialism and apartheid, and as such, there is a need to transform the education system to ensure equal opportunity for all learners, and ultimately economic growth and security for the country. One of the explanations offered for the crisis in learner performance is the poor teacher education system. However, there is a paucity of research in teacher education generally in South Africa, and specifically in relation to pre-service teachers. Furthermore, little attention has been given to how initial teacher education could contribute to the promotion of a social justice agenda with the intention of transforming the South African schooling system. This research seeks to understand how the expectations, scaffolding and assessment of preservice teachers’ teaching practices can be utilised to promote social justice during the Teaching Practice (TP) component of initial teacher education. In answering the research question, I analyse data and literature to identify a set of key valued functionings of quality praxis that preservice teachers ought to be provided the capability to realise, at the level of achieved functioning. This is a qualitative case study located in the interpretive paradigm. The case under study is: quality teaching practices of pre-service teachers. This case is bound by context (initial teacher education in South Africa) and setting (the pre-service teacher in the classroom). Two South African Higher Education Institutions (HEIs) were selected through purposive sampling and their respective Teaching Practice (TP) documentation was analysed. Focus group interviews were conducted with five lecturers involved in TP at one of the HEIs. The theoretical framework of the study used to guide the analysis of the data was underpinned by a social justice perspective on quality education. Given that a social justice perspective does not have analytic tools, I view quality pre-service teachers’ teaching practices as praxis and utilise the capability approach as a mechanism for identification and description of valued functionings and capabilities that contribute to quality praxis. There are four significant findings in my research. Firstly, there is consistency with regards to the valued functionings and capabilities across the TP documentation of the two participating HEIs. In other words, the conceptions of a capable pre-service teacher are similar. Secondly, if social justice goals are to be realised, greater clarity of the valued functionings needs to be evident in the TP documentation. Thirdly, the valued functionings can be categorised into those that are foundational and those that promote a social justice agenda. Finally, in promoting a social justice agenda, there are functionings that ought to be valued by the HEIs that are seemingly not currently valued.
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  • Date Issued: 2018

Deriving norms for learners in the disadvantaged schools of the peri-urban areas of the Eastern Cape: the case of the Vassiliou Mathematics Proficiency Test (VASSI)

  • Authors: Masango, Siphesihle Polkadot
  • Date: 2017
  • Subjects: VASSI Mathematics Proficiency Test , Mathematical ability -- Testing -- South Africa , Educational tests and measurements -- South Africa , Children with social disabilities -- Education -- South Africa , Children with social disabilities -- Education -- South Africa -- Makhanda -- Case studies
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/49929 , vital:25943
  • Description: This study builds on South African cross-cultural research which highlights the need for careful stratification of normative samples for quality of education and geographical location. The aim of the present study was to produce an expanded set of preliminary norms for learners in the disadvantaged schools of the peri-urban areas of the Eastern Cape, Grahamstown, on the Vassiliou Mathematics Foundation Phase Test (VASSI) and Vassiliou Mathematics Proficiency Test (VASSI), respectively. The test was administered to Grade 1-6 learners in four different schools all within Joza location, Grahamstown. For the learners’ convenience the tests were translated into isiXhosa, the translations were provided together with the original English questions. Archival data collected by honours students was also incorporated in this study. The total number of participants was N=724 which was comprised of 147 grade 1s, 123 grade 2s, 117 grade 3s, 128 grade 4s, 113 grade 5s and 96 grade 6s. Norm-referenced criterion was used in analysing the data. The results of this study are in accordance with those purporting the low performance of disadvantaged learners on the school subject, mathematics. Stanines for the various grades (Grade 1 to 6) were calculated and are presented in the study. This study has demonstrated that although gender, language and other ethnic variables have an impact on mathematics performance, quality of education and socioeconomic status have a significant effect. Further research is needed on the effect of quality of education and socioeconomic status on learners in disadvantaged schools on this test in particular.
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  • Date Issued: 2017

Photosynthetic and growth responses of C3 and C4 grasses to short- duration sunflecks and resultant consequences for their performance in understory environments

  • Authors: Adams, Claire Elizabeth
  • Date: 2017
  • Subjects: Understory plants -- Effect of light on , Grasses -- Effect of light on -- South Africa , Erharta -- Effect of light on , Brachiara -- Effect of light on
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/5016 , vital:20753
  • Description: Low C4 grass species abundance in understory environments is thought to be as a result of their high-light requirements, lack of photosynthetic advantage relative to C3 species in cooler environments, and an inability to adequately utilise sunflecks. This study sets out to investigate this theory, hypothesizing that C3 grass species outperform C4 grass species under the canopy, not as a result of quantum efficiency temperature effects, but as a result of C4 species inability to utilize short-duration sunflecks. Short sunflecks could result in a breakdown in assimilate movement between the mesophyll (MSC) and bundle sheath (BSC) cells. The role of BSC leakiness, stomata and PSII efficiency on the ability of C3 and C4 Alloteropsis semialata to utilize short-duration sunflecks was investigated using gaseous exchange and chlorophyll fluorescence techniques, while the growth of both subspecies under a simulated flecking-light environment tested whether these measured responses translated into effects on growth. As C3 grasses are known to possess higher levels of stomatal conductance in relation to C4 species, results showed that C3 A. semialata was able to utilize short-duration sunflecks as a result of increased stomatal conductance and an ability to induce photosynthesis under various light flecking conditions. In contrast, C4 A. semialata was unable to utilize sunflecks possibly as a result of energetic limitations of the carboxylation mechanism (PSII) and not because of increased bundle sheath leakiness. These photosynthetic responses translated into growth differences when both types were grown in an artificially flecking light environment. The photosynthetic differences noted for C3 and C4 A.semialata were also evident in shade adapted understory grasses; Erharta erecta (C3), Dactylotenium australe (C4) and Brachiaria chusqueoides (C4). As photosynthetic induction was marginally more rapid in all species relative to A. semialata it suggests some degree of adaptation in shade grasses, however the inability of the C4 species to utilise short sunflecks remained. As a result, it was hypothesized that C3 shade adapted E. erecta and C4 B. chusqueoides, co-inhabiting the same forest understory, are able to do so because of differences in light micro-environments associated with each species. However, canopy openness and light profiles determined for theses micro-climates showed no differences and that both species have persisted within a relatively stable understory environment. The coexistence was possible as the understory was supplied with a significant proportion of its daily light in flecks sufficiently long as to not compromise C4 productivity. A survey of 10 species of grasses under various canopy densities and in the open showed a strong negative linear relationship between canopy openness and the rate at which photosynthesis was induced by flecking light, which has not been shown before. This did not result from the phylogenetic relationship between species and could be shown for a single species (E. erecta) growing in a range of light environments. This demonstrates that C4 grasses, despite adaptation, would be limited from sunfleck environments if a significant proportion of the daily light available consists of flecks of short-duration. The generation of such environments may occur as a result of woody thickening and could help explain the observed decline in C4 grasses under these conditions.
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  • Date Issued: 2017

Normative self-perceptions of journalists in Nigeria : the case of the Guardian newspaper

  • Authors: Tiri, Judith
  • Date: 2014
  • Subjects: Guardian (Nigeria) , Nigeria -- In mass media , Nigeria -- Politics and government -- In mass media , Newspapers -- Nigeria , Journalism -- Political aspects -- Nigeria , Journalists -- Nigeria -- Psychology
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3523
  • Description: The study aims at interrogating the self - perceptions of journalists in Nigeria. The study is an attempt to answer some questions as: what contributions have journalists made to the democratization of Nigeria from 1960 to date? What role(s) did the media play during and after the transition to democracy? To what extent have the activities of politicians and the business class affected t he media’s social responsibility? What are the self-perceptions of journalists working in Nigeria’s The Guardian newspaper? The studies on normative theories of the press, Journalism Culture, and the perceived influences on journalism practice in a democra cy were adapted to answer the afore-listed questions. The works on how elite continuity and transitology models affect the perceptions of journalists in new democracies were also used to answer the questions posed. Since the field of research of the preced ing works is the West, the Nigerian experience points to issues that were not addressed in the prior studies because of the latter’s unique socio-political, historical, economic and ethno-religious structures . The data were collected and analyzed according to the QualitaQualitative paradigm, using in-depth semi-structured individual interviews with journalists working at The Guardian newspaper. The findings suggest that the journalists have made positive contributions to Nigeria’s democratization. The journalists that support this thesis claim that the self-perceptions of their role have changed from an adversarial position to a democratically-defined social responsibility role. This is because journalists ensure that government policies are implemented and the iss ues that affect the masses are reported. The findings show that in spite of the shift to democratization some challenges have remained, for example the journalists’ lives are not safe ; they collect bribes which are popularly called brown envelopes in Nigeria, write biased stories, and hold partisan relationships with the politicians and entrepreneurial elites and so on. The study acknowledges that democratization is in a continuum and that (the stakeholders or) civil society, journalists, the state and the entrepreneurial elites must contribute to deepen Nigeria’s democracy. The study suggests a self-perception theory that uses individual structures and institutions of a country to guide the stakeholders to play roles that will deepen democracy.
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  • Date Issued: 2014

Field and laboratory measurements of polarization mode dispersion in optical fibres

  • Authors: Viljoen, Lawrence
  • Date: 2005
  • Subjects: Optical fibers
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:10513 , http://hdl.handle.net/10948/375 , Optical fibers
  • Description: In this dissertation, the PMD measurements of field and laboratory optical fibre will be discussed. In the laboratory, temperature cycling of different configurations of fibre were tested. It is shown that the environmental temperature plays a significant role in determining the behaviour of PMD. The PMD of all fibres tested showed changes in the PMD when the environmental temperature was changing, but remained constant for constant temperatures. This is explained by the structure and thermal coefficients of the materials used to make up the fibres. It is found that the temperature gradient has a large effect on the magnitude of the PMD fluctuations. Field measurements were conducted on buried and aerial cable. It is shown that the PMD of aerial cables shows a higher degree of scatter than the PMD of buried cables. The scatter seen in the PMD can be attributed to changing environmental temperature as well as movement of the cable. The PMD of the deployed fibre is in all cases found to be considerably higher than the PMD of laboratory fibre. Age of the fibre, deployment conditions and installation procedures are believed to be responsible for the higher value. Long term monitoring of the PMD is also found to be critical when testing fibres. Over- or underestimations of the average PMD are often made in the field due to only a limited number of readings being taken. Having a large test ensemble of input states of polarization is shown to increase the accuracy of the results. For aerial cables, movement of the cable has the same effect as scrambling the input SOP and hence the results will be more accurate. Buried cables on the other hand show little movement and hence only one input SOP is often tested. Scrambling the input SOP will therefore increase the accuracy of these results.
  • Full Text:
  • Date Issued: 2005

An investigation into the effects of socio-economic and education factors on WAIS-III performance in a stratified South African sample

  • Authors: Kemp, Ryan
  • Date: 2000
  • Subjects: Wechsler Adult Intelligence Scale -- South Africa , Intelligence tests -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3002 , http://hdl.handle.net/10962/d1002511 , Wechsler Adult Intelligence Scale -- South Africa , Intelligence tests -- South Africa
  • Description: The present study examined the effects of socio-economic status, quality and level of education on performance on the Wechsler Adult Intelligence Scale 3rd Edition r.:w AIS-III). The study was conducted within the context of the present Human Sciences Research Council (HSRC) W AIS-III standardisation process, cross-cultural psychometric research and the notion of test-wiseness. A South African sample (N = 68) comprising African first language (n = 40) and English first language (n = 28) participants, stratified for age (19 - 30 years), gender and educational attainment (Matric and Graduate) were utilised. Effects due to quality of education were determined by dividing the African language participants into those with private/model C schooling (n = 20) and those with DET schooling (n = 20). Effects due to level of education were determined by dividing the entire sample into those with Matric level education (n = 34) and those with Graduate level education (n = 34). Detailed demographic and socio-economic information were recorded for all participants, who completed the entire American version of the W AIS-III. Results revealed a highly significant positive correlation between high socio-economic status and W AIS-III Full Scale IQ. In addition the respective impact of the relatively poor quality of education and lower level of educational attainment on W AIS-III performance was substantial. These results were discussed in terms of their implications for cross-cultural research, the HSRC standardisation of the W AIS-III and the practical use of the W AIS-III in neuropsychological assessment.
  • Full Text:
  • Date Issued: 2000

Organisation development: a formative evaluation of an OD intervention

  • Authors: Routledge, Michael Henry Collis
  • Date: 1999
  • Subjects: Organizational change , Organizational behavior , Action research , Psychology, Industrial
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3044 , http://hdl.handle.net/10962/d1002553 , Organizational change , Organizational behavior , Action research , Psychology, Industrial
  • Description: Rapid changes and increased competitiveness in business environments, together with greater demands by employees for improvements in the quality of their work lives, make it necessary for organisations to review their operating styles and functions. Many companies have found an answer in Organisation Development (OD) which focuses on ways in which people associated with organisations learn to diagnose and solve those problems which limit organisational effectiveness. The present study evaluates the progress of an OD intervention underway in an organisation in Zimbabwe. A formative evaluation is undertaken during an OD intervention. It is designed to assess the change effort's progress in such a way that steps can subsequently be taken to correct, modify or enhance such aspects of the intervention as may be determined by the evaluation. The study begins with a review of the company's original and revised Mission Statements as well as the present and last two sets of corporate three-year plans. These documents inform the construction of an interview guide. Individual interviews are then used to ascertain attitudes of respondents to the OD intervention and the changes it is bringing about. In addition the interviews are used to gauge the degree of commitment of respondents to the intervention. All the senior managers in the organisation are interviewed as well as the holding company's chief executive and the external consultant facilitating the intervention. The study records fundamental changes taking place in the attitudes of top managers and the first signs of an impact of these attitude changes on the formulation of company plans. Management styles and the culture of the organisation also show some change and influence on routine business operations. In addition there are early indications of an alteration of behaviour at other levels in the organisation. Business outcomes are improving and it is proposed that the benefits are due to fortuitous market developments assisted to an extent by the culture and attitude changes brought about by the OD intervention.
  • Full Text:
  • Date Issued: 1999

An investigation commissioned by the National Union of Mineworkers

  • Authors: NUM
  • Date: July 1985
  • Subjects: NUM
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/134861 , vital:37212
  • Description: The University of the Witwatersrand has a long established relationship with the mining industry. Indeed, its origins go back to the South African School of Mines established in Kimberley in 1896. (1). Since 1917, the Chamber of Mines has given direct grants to the University and its predecessors. In fact, the Chamber remains our largest private donor. Murray has shown in his authoritative study of the early years of the University that there have been occasions in our history when the Chamber has felt that it has not received a satisfactory return upon its massive investment in the University (2). On balance, however, the University can rightly claim to have served the Chamber well over the years. In recent years, the other side of the industry's history and social structure has been a focus of systematic investigation in this University. Here, van Onselen's Chibaro stands out : a pioneering attempt to create historically the social world of the compound in the early years of the mining industry in Southern Rhodesia. In our own Department, Moodie, Bozzoli, and Innes have all contributed to our knowledge of the social structure of mining.
  • Full Text:
  • Date Issued: July 1985

Some properties of a model F1 layer of the ionosphere

  • Authors: De Jager, Gerhard
  • Date: 1963
  • Subjects: Ionosphere , Ionospheric electron density
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5515 , http://hdl.handle.net/10962/d1011046 , Ionosphere , Ionospheric electron density
  • Description: The present work was initially aimed at providing an explanation for some of the phenomena that occur in the ionosphere at sunrise. The approach that was taken was to determine the changes that take place on a theoretical model of the ionosphere and then to compare these with observations. A prerequisite for this approach was a theoretical model that would show, among other things, a bifurcation of the F layer during daytime without making unjustified arbitrary assumptions. The absence of such a model, particularly as far as non-equilibrium conditions are concerned, resulted in the present attempt to provide such a model for the F1 region.
  • Full Text:
  • Date Issued: 1963
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