The effect of habitat and spatial management on reef fish in an established marine protected area
- Authors: Dames, Vivienne Abigail
- Date: 2021
- Subjects: iSimangaliso Wetland Park (South Africa) -- Management , Reef fishes -- South Africa -- KwaZulu-Natal , Baited remote underwater stereo-video systems (stereo-BRUVs) , Marine parks and reserves -- Monitoring -- South Africa -- KwaZulu-Natal , Fish populations -- Measurement
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171150 , vital:42024
- Description: The persistence of harvested fish populations in the Anthropocene will be determined, above all, by how they respond to the interacting effects of climate change and fisheries exploitation. Predicting how populations will respond to both these threats is essential for any adaptive and sustainable management strategy. The response of fish populations to climate change is underpinned by physiological rates and tolerances, and emerging evidence suggests there may be physiological-based selection in capture fisheries. By quantifying important physiological rates of a model species, the endemic seabream, Chrysoblephus laticeps, across ecologically relevant thermal gradients and from populations subjected to varying intensities of commercial exploitation, this thesis aimed to 1) provide the first physiologically grounded climate resilience assessment for a South African linefish species, and 2) elucidate whether exploitation can drive populations to less physiologically resilient states in response to climate change. To identify physiologically limiting sea temperatures and to determine if exploitation alters physiological trait distributions, an intermittent flow respirometry experiment was used to test the metabolic response of spatially protected and exploited populations of C. laticeps to acute thermal variability. Exploited populations showed reduced metabolic phenotype diversity, fewer high-performance aerobic scope phenotypes, and a significantly lower aerobic scope curve across all test temperatures. Although both populations maintained a relatively high aerobic scope across a wide thermal range, their metabolic rates were compromised when extreme cold events were simulated (8 °C), suggesting that predicted future increases in upwelling frequency and intensity may be the primary limiting factor in a more thermally variable future ocean. The increment widths of annuli in the otoliths of C. laticeps from contemporary and historic collections were measured, as a proxy for the annual growth rate of exploited and protected populations. Hierarchical mixed models were used to partition growth variation within and among individuals and ascribe growth to intrinsic and extrinsic effects. The best model for the protected population indicated that the growth response of C. laticeps was poorer during years characterised by a high cumulative upwelling intensity, and better during years characterised by higher mean autumn sea surface temperatures. The exploited population growth chronology was too short to identify an extrinsic growth driver. The growth results again highlight the role of thermal variability in modulating the response of C. laticeps to its ambient environment and indicate that the predicted increases in upwelling frequency and intensity may constrain future growth rates of this species. A metabolic index (ϕ), representing the ratio of O2 supply to demand at various temperatures and oxygen concentrations, was estimated for exploited and protected populations of C. laticeps and used to predict future distribution responses. There was no difference in the laboratory calibrations of ϕ between populations, and all data was subsequently combined into a single piecewise (12 °C) calibrated ϕ model. To predict the distribution of C. laticeps, ϕ was projected across a high-resolution ocean model of the South African coastal zone, and a species distribution model implemented using the random forest algorithm and C. laticeps occurrence points. The future distribution of C. laticeps was estimated by predicting trained models across ocean model projections up to 2100. The best predictor of C. laticeps’ current distribution was minimum monthly ϕ and future predictions indicated only a slight range contraction on either edge of C. laticeps’ distribution by 2100. In order to provide policy makers, currently developing climate change management frameworks for South Africa’s ocean, with a usable output, the results of all research chapters were combined into a marine spatial model. The spatial model identified areas where C. laticeps is predicted to be resilient to climate change in terms of physiology, growth and distribution responses, which can then be prioritised for adaptation measures, such as spatial protection from exploitation. While these results are specific to C. laticeps, the methodology developed to identify areas of climate resilience has broad applications across taxa. From a global perspective, perhaps the most salient points to consider from this case study are the evidence of selective exploitation on physiological traits and the importance of environmental variability, rather than long-term mean climate changes, in affecting organism performance. These ideas are congruent with the current paradigm shift in how we think of the ocean, selective fisheries, and how they relate to organism climate resilience.
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- Date Issued: 2021
The impact of labour legislation on selected small firms in Mbombela (Nelspruit)
- Authors: Dlamini, Sikhulile Blessing
- Date: 2021
- Subjects: Labor laws and legislation -- South Africa , Small business -- Law and legislation-- South Afric , Small business -- South Africa -- Mbombela -- Case studies
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/170781 , vital:41959
- Description: This study uses the theoretical framework of industrial relations pluralism, to study and analyse the impacts of labour legislation on six small firms (employing less than 50 workers) based in Mbombela (formerly Nelspruit), Mpumalanga province, South Africa. The analysis is based on the viewpoints of six managers and how they see the impacts of labour legislation on their respective firms. The analysis is aided by utilising theory and literature to make sense of the manager perspectives on the topic. Also, utilising a qualitative research design to collect and analyse the data, the study presents diverse findings in terms of how the participants perceived and experienced certain types of legislation. Some managers believed that the benefits of labour legislation outweighed the costs. While others believed the exact opposite. At an overall level, the study revealed that most of the participants were not as severely affected by labour legislation as might be expected; given the scarcity of resources in most small firms. This was partly because of various coping strategies and practices (mostly involving the use of informal procedures) that were adopted by the firms. Also, some small firms who aimed at expanding their businesses strategised to adopt some formal procedures and practices in order to easily absorb labour legislation and subsequently mordenise their businesses in the process. While a few firms persisted with more informal customs as they appeared cost-effective and necessary in their particular market positioning.
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- Date Issued: 2021
The invasion ecology of Pontederia cordata L. (Pontederiaceae) in South Africa
- Authors: Wansell, Sage Nora-Lee
- Date: 2021
- Subjects: Plant invsions -- South AFrica , Invasive plants -- Ecology -- South Africa , Pontederiaceae -- South AFrica
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172433 , vital:42200
- Description: Pontederia cordata L. (Pontederiaceae) is a tristylous invasive macrophyte – originating from North and South America – that has caused detrimental environmental, agricultural and socio-economic impacts in South Africa (SA). This novel study investigates the invasive ecology of P. cordata in SA by determining population genetics, pollination ecology and floral traits. Preliminary field surveys suggest that only one of three tristylous forms of P. cordata is invading SA and no seeds have been observed in any invasive populations. This study therefore determined the population genetics, mode of spread of P. cordata in SA and possible reasons for the lack of seed production, as well as providing suggestions for future control and management strategies. Inter Simple Sequence Repeats of leaf samples from invasive populations in SA and the native range of the United States of America (USA) were performed to determine the population genetics of P. cordata. The clarification of population structure of an alien invasive plant can provide insight into founder effects, introduction events and modes of spread and is important for the development of management plans such as biological control. Results from the genetic analyses indicated that P. cordata populations have low genetic diversity within and amongst invasive populations in comparison to native populations. This suggests that high gene flow and sexual reproduction is not present in invasive populations, and that only a single or very few introductory events have occurred in SA. Furthermore, invasive P. cordata populations shared the highest genetic similarity with native samples from Belle Haven, Virginia, USA, and thus further sampling and future genetic surveys should be conducted in this area to identify source populations to survey for potential biological control agents. Following these findings, I investigated whether sexual reproduction and seed production is absent from invasive P. cordata populations in SA as speculated. Floral traits from populations throughout all the invaded provinces were measured and, along with pollen grain measurements, it was determined that only short-morphed plants are present in SA. It was speculated that the absence of native pollinators in the invasive range may be responsible for the absence of sexual reproduction. However, a pollination study confirmed the presence of generalist insect pollinators. Thereafter, artificial pollination experiments on 8 865 flowers were conducted to determine whether an incompatibility system was present which prevented seed production. No seeds were produced and it was concluded that illegitimate pollination of the short-morphed plants prevented seed production and rhizomes are responsible for the invasion of P. cordata throughout SA. The implications of these findings and possible management strategies such as biological control is discussed in Chapter 4. These findings suggest that control programmes should target the plants rhizomes to prevent and reduce spread. Preventing the introduction of medium- and long-morphed plants into SA is crucial to prevent P. cordata from producing seeds and intensifying invasion further through both asexual and sexual spread.
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- Date Issued: 2021
The potential conflict of interest associated with the management of Rosa rubiginos L. (Rosehip) in South Africa
- Authors: Westwood, Timothy
- Date: 2021
- Subjects: Invasive plants -- South Africa , Biological invasions -- Economic aspects , Rose hips -- Economic aspects -- South Africa , Roses -- South Africa , Rose culture -- Economic aspects -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/172458 , vital:42204
- Description: Rosa rubiginosa L. is a category 1b invasive plant species in South Africa and must be controlled according to NEM:BA. However, R. rubiginosa has the potential to provide economic benefit in South Africa due to the expanding market for the shrubs fruit, rosehips. The shrub is not permitted to be cultivated in South Africa due to legislation, limiting the economic potential as the rosehips are only able to be collected from wild R. rubiginosa shrubs. In order to expand the rosehip market in South Africa a downgrade or removal of R. rubiginosa from the invasive species list would be required, as wild harvest is limited. This study aims to assess the benefits and cost associated with R. rubiginosa in order to determine whether the legislation should be altered allowing for the cultivation of the shrub in South Africa. Due to the limited literature surrounding R. rubiginosa three different questionnaires and a case study were used in order to assess the benefits and negatives associated with the shrub. Experts in the field of invasion biology were surveyed to bridge the gap in the R. rubiginosa literature. Landowners, where the shrub is abundant, were surveyed to determine the negative impacts of R. rubiginosa. Rosehip companies were surveyed in order to determine the current size and potential of the R. rubiginosa (rosehip) market. The case study looked at how a rosehip company would benefit if R. rubiginosa was allowed to be cultivated in South Africa. The study found R. rubiginosa to have great economic potential and market growth, with very little negative economic impact. The case study showed that one rosehip company would grow from 1500 tons of raw rosehip to 20 000 tons if cultivation was allowed, resulting in a growth in turnover from R57 million to R760 million ($1=R14.8). The findings in the study show that R. rubiginosa does not significantly affect landowners where it is abundant. Therefore, it is suggested that a change to the legislation should be considered allowing for the cultivation of R. rubiginosa should be implemented.
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- Date Issued: 2021
The relationship between organisational leadership and job satisfaction of three generational age groups in a school context
- Authors: Haasbroek, Juan Gert Diedericks
- Date: 2021
- Subjects: Educational leadership -- South Africa , High Schools -- Administration -- South Africa -- Western Cape , Management , High school teachers -- South Africa -- Western Cape -- Case studies , High school teachers -- South Africa -- Western Cape -- Job satisfaction , High school teachers -- South Africa -- Western Cape -- Attitudes
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/170802 , vital:41961
- Description: With multiple generations in education, there are different leadership styles preferred by schoolteachers that affect their job satisfaction (Cufaude and Riemersma, 1999:1-3). Schools should ensure that leadership works toward satisfied teachers to reach sustainable organisational performance. The resource-based view argues that organisations should look within the organisation, particularly human resources, to find sources that lead to improved organisational performance (Jurevicius, 2013:1). Therefore, organisations should equip themselves with the required leadership style(s) to meet employee expectations. Furthermore, it is imperative to look at different generations within the school’s context, as it will strengthen or weaken the relationship between organisational leadership and job satisfaction. The study adopted a quantitative approach, using the Multiple Leadership Questionnaire and the Minnesota Satisfaction Questionnaire as instruments for collecting primary data. The population consists of high school teachers in the Eden District, Western Cape that work at affluent schools, which are declared as quantile 4 and 5 model schools. There is a total of 13 high schools that fall within this specification with a total population of 220 teachers. In total, 111 questionnaires were distributed, of which 73 were returned. Sixty-eight were considered usable. Both sample parameters specified by the research instruments were met. The primary purpose of the study was to investigate the relationship between leadership within the organisation (referring to transformational, transactional, and passive-avoidant organisational leadership styles) and employee job satisfaction of high school teachers in the Eden District. Different generations, from the age group perspective, is composed as a moderating variable in the relationship between organisational leadership and job satisfaction. The empirical study established that the independent variables, the leadership styles employed by the organisation, are directly related to employee job satisfaction. Of the three independent variables, transformational leadership and, to a lesser extent, transactional leadership proved to have a positive association with job satisfaction. In contrast, passive-avoidant leadership has a negative relationship with job satisfaction. It is also established that the relationship is stronger or weaker based on generations, positioning generations from the age group perspective as satisfactory moderator. It was found that Millennials prefer the transactional leadership style as this will strengthen the relationship between organisational leadership and job satisfaction. Baby Boomers prefer transformational leadership for the greatest positivity. To a lesser extent, transactional leadership will also contribute to the relationship’s strength between organisational leadership and job satisfaction. Generation X is indifferent to transactional or transformational leadership.
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- Date Issued: 2021
The views of amakrwala on the meaning of umqombothi and commercial alcohol use during the initiation ceremonies
- Authors: Mavimbela, Mzoli
- Date: 2021
- Subjects: Youth -- Alcohol use , Alcoholism -- South Africa , Alcoholism -- Psychological aspects , Initiation rites -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/60862 , vital:68801
- Description: Ulwaluko or initiation ceremony is one of the most important ceremonies practiced by the amaXhosa ethnic group to mark male adolescents’ transition from boyhood to manhood. Every young Xhosa male is anticipated to undergo this ceremony in order to be respected and be viewed as a true man by the society. There is a dearth of literature on amakrwala’s views regarding the meaning of traditional beer (umqombothi) and commercial alcohol (brandy or beer) use during the initiation ceremony. Thus, this study addresses this gap, as it adds to the existing spectrum of knowledge on the meaning of alcohol use during the amaXhosa initiation process. The socio-cultural theory was selected as the theoretical framework for the study. This study took a qualitative nature which was exploratory-descriptive and contextual in design employing a non-probability purposive-criterion based technique to sample 16 identified amaXhosa adult males between the ages of 18 to 24 years who recently went through the initiation ceremony. Sixteen individual semi-structured telephonic interviews were conducted. Data collected was analysed using thematic data analysis. Various data verification strategies were employed to ensure trustworthiness. Research ethics applicable to this study were guided by the principles contained in the Belmont report (1979). The findings showed that during the amaXhosa initiation ceremony both commercial alcohol and umqombothi played significant but different roles during each stage of the ceremony. The majority of amakrwala viewed umqombothi as a significant beer for ancestors to divinely bless isiko while brandy and beer were viewed as sweets or beers for fun which accompanied umqombothi. Brandy and beer were viewed as beers required by abafana teaching amakrwala manhood in the lighthouses. Thus, negative behaviours portrayed by abafana during imigidi after drinking alcohol were viewed as a great concern by amakrwala. 7 Alcohol use in ulwaluko was viewed as good by the amakrwala but they emphasized that there should be guidelines that monitor responsible drinking.
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- Date Issued: 2021
Towards the development of a pro-environmental strategy for improving catch-and-release behaviour in recreational fisheries – a case study on a competitive South African angling body
- Authors: Mannheim, Samantha L
- Date: 2021
- Subjects: Fishing -- Environmental aspects -- South Africa , Fishing -- South Africa , Fishers -- Attitudes -- South Africa , Fishers -- Attitudes -- South Africa -- Cast studies , Fishes -- Conservation -- South Africa , Rock and Surf Super Pro League , Southern African Fisheries Ecology Research Lab
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171862 , vital:42133
- Description: Catch-and-release (C&R) is becoming increasingly popular in recreational fisheries with the potential to contribute towards conserving the oceans limited fish stocks. Several studies have highlighted high rates of mortality and many sub-lethal effects which ultimately have a negative impact on fish population viability. With poorly developed handling practices, the fish that are released suffer the consequences of physical and physiological stress and do not always survive, thus making the ethics of C&R fishing questionable. Many studies have contributed to our understanding of the factors that influence the fate of fish released by anglers. Despite this, few interventions have been able to improve angler C&R behaviour. Pro-environmental behavioural strategies however hold some potential for improving angler C&R behaviour. To test their potential, we partnered with the South African Rock and Surf Super Pro League (RASSPL Africa), the biggest exclusively C&R competitive shore-based angling league in South Africa. The first two years (2013 and 2014) of the partnership were purely focused on building trust and relationships and making observations on angler behaviour. In 2015, we collected baseline data on angler behaviour and fish health during the RASSPL national fishing competition. This was followed by comparable data collection at the following two national competitions in 2016 and 2017 after the introduction of a combination of pro- environmental behaviour interventions, including rule changes, improving angler knowledge, behavioural modelling, rewards, penalties and feedback to improve C&R behaviour. There were significant improvements in angler behaviour, including a decline in total air exposure from 101.93s ± 64.34 in 2015 to 77.37s ± 60.52 in 2017 (F(2,618) = 9.27, P < 0.01), and the time taken for an angler to place their fish into a bucket declined from 105.86s ± 69.47 in 2015 to 23.05s ± 24.13 in 2017 (F(2,556) = 158.71, P < 0.01). There were also improvements in the health of the fish, with a decline in the blood lactate concentration and mean reflex action mortality predictor (RAMP’s) scores for the dominant species, Diplodus capensis (lactate – 9.46 ± 3.80 mmol.l-1 in 2015 and 6.69 ± 2.99 mmol.l-1 in 2017, RAMP – 0.28 ± 0.22 in 2015 and 0.19 ± 0.17 in 2017), and Haploblapharus fuscus (lactate – 4.25 ± 1.89 mmol.l-1 in 2015 and 1.76 ± 0.78 mmol.l-1in 2017, RAMP – 0.15 ± 0.18 in 2015 and 0 ± 0 in 2017). In 2018, surveys were conducted to gain insight into angler demographics and external (social, economic, cultural and institutional) and internal factors (knowledge and awareness, motivations, attitudes and perceptions) associated with the RASSPL anglers. Surveys were also designed to assist in identifying what components were key drivers behind the angler’s behavioural changes. The demographic characteristics of RASSPL anglers were not dissimilar from the general recreational angling public in South Africa, suggesting that this kind of intervention may have potential at a broader scale. In terms of the drivers of behavioural change, the surveys revealed that 68% of respondents strongly agreed that the structural rule changes contributed to their improved behaviour. This was followed by the educational presentations (66% of the respondents) and modelling / demonstrative videos (59% of the respondents). The conservation prizes were considered less effective, with only 27% of anglers strongly agreeing that this intervention improved their C&R behaviour. Overall this study has demonstrated that it is possible to improve the C&R behaviour of anglers in a competitive setting, with the most effective component of the intervention being the use of rule changes (structural approach). These findings suggest that proenvironmental strategies hold potential for improving the C&R behaviour of anglers and the health of released fishes. It is suggested that interventions to improve C&R behaviour should aim to develop long-term relationships, and implement a broad range of well communicated strategies based on reliable data and sound rationality. Key words: marine shore-based fisheries; community engagement; pro- environmental behaviour; behavioural intervention.
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- Date Issued: 2021