Potential suppressive effects of alien Acacia melanoxylon on Afrotemperate Forest tree recruitment
- Miles, Bayleigh, Baard, Johan
- Authors: Miles, Bayleigh , Baard, Johan
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55391 , vital:51989
- Description: Acacia melanoxylon R.Br. is a prominent alien and invasive species in many parts of the world and evidence exists of its adverse effects on indigenous forest community composition through allelopathy and alteration of light regimes. The species also occurs extensively in Southern Cape Afrotemperate Forest (South Africa) and is thought to suppress indigenous Afrotemperate Forest tree seedlings through various mechanisms such as the alteration of natural light regimes or allelopathy, although this has not been rigorously verified. This study aimed to investigate whether Acacia melanoxylon has a suppressive effect on Afrotemperate Forest tree recruitment. Firstly, we assessed the potential allelopathic effect of Acacia melanoxylon and an indigenous Afrotemperate Forest species Olea capensis macrocarpa (C.H.Wright) I.Verd. on the germination of Acacia melanoxylon and three prominent indigenous tree species’ seedlings in a nursery trial. Germination of the indigenous species failed; however, we were able to compare the germination of Acacia melanoxylon among the three treatments, namely Acacia melanoxylon leachate, Olea capensis leachate, and no leachate. The average germination of Acacia melanoxylon was 67% and germination was marginally higher under Acacia melanoxylon leachate and Olea capensis leachate, respectively, than under the control. This suggested that germination of the species is improved, or at the least, unaffected, by leachates of itself or that of a common indigenous canopy species. We then critically evaluated the germination requirements of the indigenous test species to determine probable reasons why their germination failed in our trial. The most plausible explanation for the germination failure could be that the trial period did not encompass an entire winter season and may not have provided adequate cold stratification. We concluded that the lack of sensitivity of Acacia melanoxylon to leachates of itself or a common indigenous overstorey species likely contribute to its success as an invasive species in Southern Cape Afrotemperate Forest. Secondly, we investigated, through field surveys, whether Acacia melanoxylon affects indigenous Afrotemperate Forest tree sapling composition and light regimes underneath its canopy. Using a paired plot design, we compared light intensity, tree sapling species richness, diversity, and density underneath 30 overstorey Acacia melanoxylon trees and 30 indigenous counterparts. We recorded 2506 indigenous tree saplings from 29 species in the 60 plots and found that there were no significant differences in richness, diversity, or v density of saplings underneath Acacia melanoxylon compared to that under indigenous counterparts. Light intensity did not differ significantly underneath Acacia melanoxylon and indigenous canopies, however light intensity varied significantly more underneath the canopies of Acacia melanoxylon. Canonical correspondence analysis of the abundance of sapling species confirmed that sapling composition was not largely determined by the overstorey species. We concluded that Acacia melanoxylon does not significantly alter indigenous tree species composition underneath its canopy at the typical densities (<3 trees per hectare) at which it occurred in the forests of the Garden Route National Park that we surveyed. Nevertheless, populations of Acacia melanoxylon in the forest interior still act as a source of propagules for invasion in forest margins, riparian areas, and neighbouring fynbos shrubland. These invasive attributes need to be considered in the management of the species in the region at large. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Miles, Bayleigh , Baard, Johan
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55391 , vital:51989
- Description: Acacia melanoxylon R.Br. is a prominent alien and invasive species in many parts of the world and evidence exists of its adverse effects on indigenous forest community composition through allelopathy and alteration of light regimes. The species also occurs extensively in Southern Cape Afrotemperate Forest (South Africa) and is thought to suppress indigenous Afrotemperate Forest tree seedlings through various mechanisms such as the alteration of natural light regimes or allelopathy, although this has not been rigorously verified. This study aimed to investigate whether Acacia melanoxylon has a suppressive effect on Afrotemperate Forest tree recruitment. Firstly, we assessed the potential allelopathic effect of Acacia melanoxylon and an indigenous Afrotemperate Forest species Olea capensis macrocarpa (C.H.Wright) I.Verd. on the germination of Acacia melanoxylon and three prominent indigenous tree species’ seedlings in a nursery trial. Germination of the indigenous species failed; however, we were able to compare the germination of Acacia melanoxylon among the three treatments, namely Acacia melanoxylon leachate, Olea capensis leachate, and no leachate. The average germination of Acacia melanoxylon was 67% and germination was marginally higher under Acacia melanoxylon leachate and Olea capensis leachate, respectively, than under the control. This suggested that germination of the species is improved, or at the least, unaffected, by leachates of itself or that of a common indigenous canopy species. We then critically evaluated the germination requirements of the indigenous test species to determine probable reasons why their germination failed in our trial. The most plausible explanation for the germination failure could be that the trial period did not encompass an entire winter season and may not have provided adequate cold stratification. We concluded that the lack of sensitivity of Acacia melanoxylon to leachates of itself or a common indigenous overstorey species likely contribute to its success as an invasive species in Southern Cape Afrotemperate Forest. Secondly, we investigated, through field surveys, whether Acacia melanoxylon affects indigenous Afrotemperate Forest tree sapling composition and light regimes underneath its canopy. Using a paired plot design, we compared light intensity, tree sapling species richness, diversity, and density underneath 30 overstorey Acacia melanoxylon trees and 30 indigenous counterparts. We recorded 2506 indigenous tree saplings from 29 species in the 60 plots and found that there were no significant differences in richness, diversity, or v density of saplings underneath Acacia melanoxylon compared to that under indigenous counterparts. Light intensity did not differ significantly underneath Acacia melanoxylon and indigenous canopies, however light intensity varied significantly more underneath the canopies of Acacia melanoxylon. Canonical correspondence analysis of the abundance of sapling species confirmed that sapling composition was not largely determined by the overstorey species. We concluded that Acacia melanoxylon does not significantly alter indigenous tree species composition underneath its canopy at the typical densities (<3 trees per hectare) at which it occurred in the forests of the Garden Route National Park that we surveyed. Nevertheless, populations of Acacia melanoxylon in the forest interior still act as a source of propagules for invasion in forest margins, riparian areas, and neighbouring fynbos shrubland. These invasive attributes need to be considered in the management of the species in the region at large. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
Assessing service delivery protests in the Nelson Mandela Bay Municipality: the case of Walmer Township
- Authors: Mdanyana, Esethu
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54492 , vital:46609
- Description: In many South Africa’s areas, citizen’s frustration with poor or slow service delivery has resulted in a surge of service delivery protests. Some of these service delivery protests are violent in nature, resulting in the damage of public and private property. Therefore, it is imperative to scrutinize service delivery protests. The South African constitution states that municipalities have the responsibility to make sure that all citizens are provided with services to satisfy their basic needs. These services include water supply, sewage collection and disposal electricity, gas supply health services, roads, storm water drainage, street lighting, municipal parks and recreation. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2021
- Full Text: false
- Date Issued: 2021-12
- Authors: Mdanyana, Esethu
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54492 , vital:46609
- Description: In many South Africa’s areas, citizen’s frustration with poor or slow service delivery has resulted in a surge of service delivery protests. Some of these service delivery protests are violent in nature, resulting in the damage of public and private property. Therefore, it is imperative to scrutinize service delivery protests. The South African constitution states that municipalities have the responsibility to make sure that all citizens are provided with services to satisfy their basic needs. These services include water supply, sewage collection and disposal electricity, gas supply health services, roads, storm water drainage, street lighting, municipal parks and recreation. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2021
- Full Text: false
- Date Issued: 2021-12
The use of photography to visualise abstracted narratives of emotions associated with trauma
- Authors: Warner, Lauren
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54585 , vital:46726
- Description: The purpose of this qualitative research study is to comment on the use of photography to visualise abstracted narratives of the emotions associated with trauma. This is a practicebased study developed on the interweaving of theoretical and practical output. The practical output produced a photographic body of work which argues in favour of an abstracted narrative for the visualisation of trauma by engaging with visualised emotions associated with trauma. The theoretical output of the study relates to three visual themes: firstly, the direct or actual moment of trauma; secondly, the triggering of the traumatic experience and lastly, the abstracted narrative of emotions associated with trauma. Photographing a traumatic event freezes a moment in which the subjects are continually engaging in the traumatic experience. Sontag (2003: 93) asserts that this type of direct photographic representation should be discouraged for fear of aestheticising pain and desensitising the viewer to horror. The study aims not to visualise actual traumatic events, but rather to engage with abstracted narratives of emotions associated with trauma experienced or felt, both directly and indirectly. This is achieved by firstly, providing a context on how the role of photography dealing with trauma has evolved to move beyond the depiction of an actual traumatic experience. Secondly, Gillian Rose’s (2016) Visual Methodologies Framework is introduced and photographers Roger Ballen’s Cut Loose (2015) and Jo Ractliffe’s 1999 work entitled Vlakplaas: 2 June 1999 (Drive-by Shooting) analysed as visual expressions of trauma. Similarly, photographers Robert Frank’s 1978 work entitled Sick of goodby’s and Manuela Thames’s 2019 work entitled Trauma are analysed to reflect on the use of abstracted narratives as they comment on personal traumatic experiences. Lastly, the body of work produced in the practice-based output of the study, Public Places: Private Spaces, are analysed as a vehicle through which emotions are associated with trauma. These traumatic experiences are visually expressed using abstracted images in triptych narratives. This study contributes to the current body of knowledge by critically addressing ways of thinking about the visualisation of trauma. This provides insight into the topic of trauma and the various ways in which it could be visualised without depicting the actual trauma (with the potential of continuously wounding or replaying trauma) and instead engaging with the visualised traumatic experience as an abstracted narrative within a South African context. , Thesis (MA) -- Faculty of Humanities, School of Visual and Performing Arts, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Warner, Lauren
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54585 , vital:46726
- Description: The purpose of this qualitative research study is to comment on the use of photography to visualise abstracted narratives of the emotions associated with trauma. This is a practicebased study developed on the interweaving of theoretical and practical output. The practical output produced a photographic body of work which argues in favour of an abstracted narrative for the visualisation of trauma by engaging with visualised emotions associated with trauma. The theoretical output of the study relates to three visual themes: firstly, the direct or actual moment of trauma; secondly, the triggering of the traumatic experience and lastly, the abstracted narrative of emotions associated with trauma. Photographing a traumatic event freezes a moment in which the subjects are continually engaging in the traumatic experience. Sontag (2003: 93) asserts that this type of direct photographic representation should be discouraged for fear of aestheticising pain and desensitising the viewer to horror. The study aims not to visualise actual traumatic events, but rather to engage with abstracted narratives of emotions associated with trauma experienced or felt, both directly and indirectly. This is achieved by firstly, providing a context on how the role of photography dealing with trauma has evolved to move beyond the depiction of an actual traumatic experience. Secondly, Gillian Rose’s (2016) Visual Methodologies Framework is introduced and photographers Roger Ballen’s Cut Loose (2015) and Jo Ractliffe’s 1999 work entitled Vlakplaas: 2 June 1999 (Drive-by Shooting) analysed as visual expressions of trauma. Similarly, photographers Robert Frank’s 1978 work entitled Sick of goodby’s and Manuela Thames’s 2019 work entitled Trauma are analysed to reflect on the use of abstracted narratives as they comment on personal traumatic experiences. Lastly, the body of work produced in the practice-based output of the study, Public Places: Private Spaces, are analysed as a vehicle through which emotions are associated with trauma. These traumatic experiences are visually expressed using abstracted images in triptych narratives. This study contributes to the current body of knowledge by critically addressing ways of thinking about the visualisation of trauma. This provides insight into the topic of trauma and the various ways in which it could be visualised without depicting the actual trauma (with the potential of continuously wounding or replaying trauma) and instead engaging with the visualised traumatic experience as an abstracted narrative within a South African context. , Thesis (MA) -- Faculty of Humanities, School of Visual and Performing Arts, 2021
- Full Text:
- Date Issued: 2021-12
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