Impact of fracking fluid on Karoo plants based on field and greenhouse experiments
- Authors: Liddell, Duncan Carlyle
- Date: 2020
- Subjects: Plants -- South Africa -- Little Karoo , Desert ecology -- South Africa Great Karoo (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49125 , vital:41603
- Description: Fracking fluid has been indicated to be detrimental to vegetation. In forest vegetation the fracking fluid caused ground vegetation to be extensively damaged with high mortality rates and trees showing premature leaf loss following application. A study by Martin (2017) investigated these effects on Karoo vegetation in a greenhouse and found it to increase stress and reduced the growth with some life forms being identified as sensitive. The current study followed on the work of Martin testing additional species in the same greenhouse and applying different treatments of fracking fluid to Karoo vegetation in their habitat. The plants were monitored by measuring their height, photosynthetic efficiency (stress), biomass allocation and the temperature of the sites. The greenhouse plants had increased growth associated with repeated fracking fluid treatments while having variable stress levels with different treatments of the fracking fluid. The farm had mixed results being generally more stressed due to the treatments, the repeated fracking fluid treatments showed greater growth. The farm vegetation was more sensitive due to prolonged drought which is suspected to play a large role in the different response to fracking fluid between the two sites. The several hypotheses based on the finding of Martin (2017) were not supported by the data in this study. However, the application of fracking fluid did affect the tree species as they were found to be sensitive, while the other plant species was generally stressed after the applications. The greenhouse study cannot accurately represent the effects of fracking fluid on the farm vegetation, due to the large difference in the environment thus, more field studies would need to be conducted to determine the effects of fracking fluid.
- Full Text:
- Date Issued: 2020
- Authors: Liddell, Duncan Carlyle
- Date: 2020
- Subjects: Plants -- South Africa -- Little Karoo , Desert ecology -- South Africa Great Karoo (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49125 , vital:41603
- Description: Fracking fluid has been indicated to be detrimental to vegetation. In forest vegetation the fracking fluid caused ground vegetation to be extensively damaged with high mortality rates and trees showing premature leaf loss following application. A study by Martin (2017) investigated these effects on Karoo vegetation in a greenhouse and found it to increase stress and reduced the growth with some life forms being identified as sensitive. The current study followed on the work of Martin testing additional species in the same greenhouse and applying different treatments of fracking fluid to Karoo vegetation in their habitat. The plants were monitored by measuring their height, photosynthetic efficiency (stress), biomass allocation and the temperature of the sites. The greenhouse plants had increased growth associated with repeated fracking fluid treatments while having variable stress levels with different treatments of the fracking fluid. The farm had mixed results being generally more stressed due to the treatments, the repeated fracking fluid treatments showed greater growth. The farm vegetation was more sensitive due to prolonged drought which is suspected to play a large role in the different response to fracking fluid between the two sites. The several hypotheses based on the finding of Martin (2017) were not supported by the data in this study. However, the application of fracking fluid did affect the tree species as they were found to be sensitive, while the other plant species was generally stressed after the applications. The greenhouse study cannot accurately represent the effects of fracking fluid on the farm vegetation, due to the large difference in the environment thus, more field studies would need to be conducted to determine the effects of fracking fluid.
- Full Text:
- Date Issued: 2020
Impacts of a trophy hunting ban on private land conservation in South African biodiversity hotspots:
- Parker, Kim, de Vos, Alta, Clements, Hayley S, Biggs, Duan, Biggs, Reinette
- Authors: Parker, Kim , de Vos, Alta , Clements, Hayley S , Biggs, Duan , Biggs, Reinette
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158219 , vital:40163 , https://0-doi.org.wam.seals.ac.za/10.1111/csp2.214
- Description: Private land conservation areas (PLCAs) have become critical for achieving global conservation goals, but we lack understanding of how and when these areas respond to global pressures and opportunities. In southern Africa, where many PLCAs rely on trophy hunting as an income‐generating strategy, a potential ban on trophy hunting locally or abroad holds unknown consequences for the future conservation of these lands. In this study, we investigate the consequences of a potential trophy hunting ban in PLCAs in two biodiversity hotspots in South Africa's Eastern and Western Cape provinces. We used semistructured interviews with PLCA managers and owners to elicit perceived impacts of an internationally imposed trophy hunting ban on conservation activities in PLCAs, and to probe alternative viable land uses.
- Full Text:
- Date Issued: 2020
Impacts of a trophy hunting ban on private land conservation in South African biodiversity hotspots:
- Authors: Parker, Kim , de Vos, Alta , Clements, Hayley S , Biggs, Duan , Biggs, Reinette
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158219 , vital:40163 , https://0-doi.org.wam.seals.ac.za/10.1111/csp2.214
- Description: Private land conservation areas (PLCAs) have become critical for achieving global conservation goals, but we lack understanding of how and when these areas respond to global pressures and opportunities. In southern Africa, where many PLCAs rely on trophy hunting as an income‐generating strategy, a potential ban on trophy hunting locally or abroad holds unknown consequences for the future conservation of these lands. In this study, we investigate the consequences of a potential trophy hunting ban in PLCAs in two biodiversity hotspots in South Africa's Eastern and Western Cape provinces. We used semistructured interviews with PLCA managers and owners to elicit perceived impacts of an internationally imposed trophy hunting ban on conservation activities in PLCAs, and to probe alternative viable land uses.
- Full Text:
- Date Issued: 2020
Impacts of cattle grazing pressure on vegetation and soil characteristics in an arid grassland of South Africa
- Authors: Botha, Gert Stephanus
- Date: 2020
- Subjects: Grazing -- Environmental aspects -- South Africa , Cattle -- Feeding and feeds -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/${Handle} , vital:39749
- Description: Natural rangelands are often degraded due to the implementation of incorrect grazing systems. One potential solution is the use of short duration, high intensity grazing. The impacts of this grazing system on, inter alia, vegetation and soil properties have not yet been comprehensively tested within the arid rangelands of South Africa. This study aimed to determine the impacts of grazing intensity on vegetation composition, forage quantity and quality, and soil compaction, soil water infiltration rates and soil chemical properties in an arid grassland in South Africa. The following three grazing treatments were compared: no grazing (NG), low intensity grazing (LIG) and high intensity grazing (HIG). A total of 18 plots (six replicates per treatment) were grazed with Bonsmara cattle. Each plot, 4 ha in size, was surveyed pre-grazing, directly after grazing, and again three, six and 12 months post-grazing. The results indicated that different grazing intensities did not affect grass diversity and the veld condition a year after grazing. Phytomass was influenced by grazing intensity, with no grazing having the highest phytomass throughout the study period. Soil compaction differed among seasons but not among treatments, with summer surveys recording the lowest soil compaction rates. The soil water infiltration rates did not differ between the three different treatments, indicating that grazing intensity did not affect infiltration rates. However, grazing did seem to improve soil nutrient levels when compared to NG. The grazed treatments had higher NH4+, K+, and organic carbon than the NG treatment. Nevertheless, there was no significant difference in nutrients levels when comparing the LIG system to the HIG system. When comparing the soil nutrients levels within a treatment over time, only the HIG treatment showed an increase in soil nutrient levels (Mg2+) over time, whereas the LIG and NG treatments showed no changed throughout the study period. Generally, the study results indicated that in the short term there was no advantage to using higher grazing intensity, although the presence of grazing (as opposed to no grazing) is advantageous to arid grassland functioning.
- Full Text:
- Date Issued: 2020
- Authors: Botha, Gert Stephanus
- Date: 2020
- Subjects: Grazing -- Environmental aspects -- South Africa , Cattle -- Feeding and feeds -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/${Handle} , vital:39749
- Description: Natural rangelands are often degraded due to the implementation of incorrect grazing systems. One potential solution is the use of short duration, high intensity grazing. The impacts of this grazing system on, inter alia, vegetation and soil properties have not yet been comprehensively tested within the arid rangelands of South Africa. This study aimed to determine the impacts of grazing intensity on vegetation composition, forage quantity and quality, and soil compaction, soil water infiltration rates and soil chemical properties in an arid grassland in South Africa. The following three grazing treatments were compared: no grazing (NG), low intensity grazing (LIG) and high intensity grazing (HIG). A total of 18 plots (six replicates per treatment) were grazed with Bonsmara cattle. Each plot, 4 ha in size, was surveyed pre-grazing, directly after grazing, and again three, six and 12 months post-grazing. The results indicated that different grazing intensities did not affect grass diversity and the veld condition a year after grazing. Phytomass was influenced by grazing intensity, with no grazing having the highest phytomass throughout the study period. Soil compaction differed among seasons but not among treatments, with summer surveys recording the lowest soil compaction rates. The soil water infiltration rates did not differ between the three different treatments, indicating that grazing intensity did not affect infiltration rates. However, grazing did seem to improve soil nutrient levels when compared to NG. The grazed treatments had higher NH4+, K+, and organic carbon than the NG treatment. Nevertheless, there was no significant difference in nutrients levels when comparing the LIG system to the HIG system. When comparing the soil nutrients levels within a treatment over time, only the HIG treatment showed an increase in soil nutrient levels (Mg2+) over time, whereas the LIG and NG treatments showed no changed throughout the study period. Generally, the study results indicated that in the short term there was no advantage to using higher grazing intensity, although the presence of grazing (as opposed to no grazing) is advantageous to arid grassland functioning.
- Full Text:
- Date Issued: 2020
Impacts of Climate Change in Determining the Ecological Reserve
- Tanner, Jane L, Griffin, Neil J, Slaughter, Andrew R, Mantel, Sukhmani K, Dabula, Pumza, Hughes, Denis A, Wolff, Margaret G
- Authors: Tanner, Jane L , Griffin, Neil J , Slaughter, Andrew R , Mantel, Sukhmani K , Dabula, Pumza , Hughes, Denis A , Wolff, Margaret G
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438128 , vital:73437 , ISBN 978-0-6392-0124-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2834 final.pdf
- Description: The intermediate and long-term impacts of climate change require evaluation of the adaptive capacity of the riverine ecosystems to pro-mote sustainability. The predicted climate change impacts are the moti-vation behind the current research which targets the knowledge gap of the impacts of climate change on the ecological Reserve (or Ecological Water Requirements [EWR]). In order for the Department of Water and Sanitation (DWS) to meet their mandate to protect aquatic ecosystems, given the constraints of climate change, it is necessary to take cogni-sance of the implications of climate change and to make the necessary adjustments and changes to the ecological Reserve determination methodology. These adjustments will help ensure that sufficient water, at the right time, distributed in the right flow pattern and of adequate quality is provided, so that key ecological processes are sustained, and that biotic communities maintain their health and integrity.
- Full Text:
- Date Issued: 2020
- Authors: Tanner, Jane L , Griffin, Neil J , Slaughter, Andrew R , Mantel, Sukhmani K , Dabula, Pumza , Hughes, Denis A , Wolff, Margaret G
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438128 , vital:73437 , ISBN 978-0-6392-0124-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2834 final.pdf
- Description: The intermediate and long-term impacts of climate change require evaluation of the adaptive capacity of the riverine ecosystems to pro-mote sustainability. The predicted climate change impacts are the moti-vation behind the current research which targets the knowledge gap of the impacts of climate change on the ecological Reserve (or Ecological Water Requirements [EWR]). In order for the Department of Water and Sanitation (DWS) to meet their mandate to protect aquatic ecosystems, given the constraints of climate change, it is necessary to take cogni-sance of the implications of climate change and to make the necessary adjustments and changes to the ecological Reserve determination methodology. These adjustments will help ensure that sufficient water, at the right time, distributed in the right flow pattern and of adequate quality is provided, so that key ecological processes are sustained, and that biotic communities maintain their health and integrity.
- Full Text:
- Date Issued: 2020
Implantation, orientation and validation of a commercially produced heart-rate logger for use in a perciform teleost fish:
- Muller, Cuen, Childs, Amber-Robyn, Duncan, Murray I, Skeeles, Michael R, James, Nicola C, Van der Walt, Kerry-Ann, Winkler, Alexander C, Potts, Warren M
- Authors: Muller, Cuen , Childs, Amber-Robyn , Duncan, Murray I , Skeeles, Michael R , James, Nicola C , Van der Walt, Kerry-Ann , Winkler, Alexander C , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148494 , vital:38744 , doi.org.wam.seals.ac.za/10.1093/conphys/coaa035
- Description: Quantifying how the heart rate of ectothermic organisms responds to environmental conditions (e.g. water temperature) is important information to quantify their sensitivity to environmental change. Heart rate studies have typically been conducted in lab environments where fish are confined. However, commercially available implantable heart rate biologgers provide the opportunity to study free-swimming fish. Our study aimed to determine the applicability of an implantable device, typically used on fusiform-shaped fish (e.g. salmonids), for a perciform fish where morphology and anatomy prevent ventral incisions normally used on fusiform-shaped fish.
- Full Text:
- Date Issued: 2020
- Authors: Muller, Cuen , Childs, Amber-Robyn , Duncan, Murray I , Skeeles, Michael R , James, Nicola C , Van der Walt, Kerry-Ann , Winkler, Alexander C , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148494 , vital:38744 , doi.org.wam.seals.ac.za/10.1093/conphys/coaa035
- Description: Quantifying how the heart rate of ectothermic organisms responds to environmental conditions (e.g. water temperature) is important information to quantify their sensitivity to environmental change. Heart rate studies have typically been conducted in lab environments where fish are confined. However, commercially available implantable heart rate biologgers provide the opportunity to study free-swimming fish. Our study aimed to determine the applicability of an implantable device, typically used on fusiform-shaped fish (e.g. salmonids), for a perciform fish where morphology and anatomy prevent ventral incisions normally used on fusiform-shaped fish.
- Full Text:
- Date Issued: 2020
Implementation of access and benefit-sharing measures has consequences for classical biological control of weeds:
- Silvestri, Luciano, Sosa, Alejandro, Mc Kay, Fernando, Vitorino, Marcello D, Hill, Martin P, Zachariades, Costas, Hight, Stephen, Weyl, Philip S R, Smith, David, Djeddour, Djamila, Mason, Peter G
- Authors: Silvestri, Luciano , Sosa, Alejandro , Mc Kay, Fernando , Vitorino, Marcello D , Hill, Martin P , Zachariades, Costas , Hight, Stephen , Weyl, Philip S R , Smith, David , Djeddour, Djamila , Mason, Peter G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150285 , vital:38964 , https://link.springer.com/article/10.1007/s10526-019-09988-4
- Description: The Convention on Biological Diversity and the Nagoya Protocol establish that genetic resources shall be accessed only upon the existence of prior informed consent of the country that provides those resources and that benefits arising from their utilization shall be shared. Pursuant to both agreements several countries have adopted regulations on access and benefit-sharing. These regulations have created a challenging obstacle to classical biological control of weeds. This paper reviews the experiences of Argentina, Brazil, South Africa, the USA, Canada and CABI in implementing access and benefit-sharing regulations and the implications these measures have on the effective and efficient access, exchange and utilization of biological control agents.
- Full Text:
- Date Issued: 2020
- Authors: Silvestri, Luciano , Sosa, Alejandro , Mc Kay, Fernando , Vitorino, Marcello D , Hill, Martin P , Zachariades, Costas , Hight, Stephen , Weyl, Philip S R , Smith, David , Djeddour, Djamila , Mason, Peter G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150285 , vital:38964 , https://link.springer.com/article/10.1007/s10526-019-09988-4
- Description: The Convention on Biological Diversity and the Nagoya Protocol establish that genetic resources shall be accessed only upon the existence of prior informed consent of the country that provides those resources and that benefits arising from their utilization shall be shared. Pursuant to both agreements several countries have adopted regulations on access and benefit-sharing. These regulations have created a challenging obstacle to classical biological control of weeds. This paper reviews the experiences of Argentina, Brazil, South Africa, the USA, Canada and CABI in implementing access and benefit-sharing regulations and the implications these measures have on the effective and efficient access, exchange and utilization of biological control agents.
- Full Text:
- Date Issued: 2020
Implementation of Professional Development Programmes For Grade R Teachers: A case study of four primary schools in Amathole West Education District, Eastern Cape
- Authors: Jumo, Theresa
- Date: 2020
- Subjects: Teachers -- Development -- Eastern Cape -- South Africa Teachers -- Vocational guidance -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/11341 , vital:39061
- Description: This study investigated the implementation of Professional Development Programmes for Grade R teachers in four primary schools in Amathole West Education District. The interpretive paradigm was employed in this study because it focused on the teachers’ professional development and their participation in a social learning interaction as community of practice. Furthermore, a qualitative approach was used for the collection of data so as to gain in-depth information on the implementation of professional development programmes. Semi-structured interviews and document analysis were used as a form of collecting data. The participants were purposively selected for the sample of this study and comprised of 4 Principals, 1 Subject Advisor and 4 Teachers. Data analysis was done in line with the research questions, aims and objectives of the study. Through the participants’ answers from schools under study, a transcript was formulated, coded and categorized in view of the implementation of Professional Development Programmes for Grade R teachers. The data revealed that Grade R teachers under study were under qualified such that none of the teachers had the recommended Diploma in Grade R qualification as stated by the Department of Basic Education. It was also found that there was diversity in the teachers’ qualifications, colleges and the length in training. The study also indicated that although professional development programmes were held, these were however not properly monitored. Findings also revealed that the intervention strategies through professional development programmes and the support given by the district and the schools were strategies through professional development programmes and the support given by the district and the schools were not adequate and consistent. As a result the participants encountered a number of challenges regarding the implementation of professional development programmes for Grade R teachers. Namely: (1) lack of appropriately qualified personnel to support the teachers both at school and the district (2) lack of adequate follow up support visits and feedbacks from both the school and the district (3) lack of proper management by the schools and (4) lack of collaboration ii and team work in the schools. Thus, there were variances in schools under study especially with regards to late release of funding for teaching and learning materials, support offered to the principals by the Department of Education. As a result, recommendations from the study suggested that the Department of Education and the District have to come up with more strategies of continuously training the teachers and the principals and offering strong and adequate support. The study also recommended the engagement of NGOs for job embedded professional development with longer in-service training periods as compared to the shot in-service professional development programs of once- off workshops. Also another suggestion that the district must monitor school based professional development programs regularly was raised in the study
- Full Text:
- Date Issued: 2020
- Authors: Jumo, Theresa
- Date: 2020
- Subjects: Teachers -- Development -- Eastern Cape -- South Africa Teachers -- Vocational guidance -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/11341 , vital:39061
- Description: This study investigated the implementation of Professional Development Programmes for Grade R teachers in four primary schools in Amathole West Education District. The interpretive paradigm was employed in this study because it focused on the teachers’ professional development and their participation in a social learning interaction as community of practice. Furthermore, a qualitative approach was used for the collection of data so as to gain in-depth information on the implementation of professional development programmes. Semi-structured interviews and document analysis were used as a form of collecting data. The participants were purposively selected for the sample of this study and comprised of 4 Principals, 1 Subject Advisor and 4 Teachers. Data analysis was done in line with the research questions, aims and objectives of the study. Through the participants’ answers from schools under study, a transcript was formulated, coded and categorized in view of the implementation of Professional Development Programmes for Grade R teachers. The data revealed that Grade R teachers under study were under qualified such that none of the teachers had the recommended Diploma in Grade R qualification as stated by the Department of Basic Education. It was also found that there was diversity in the teachers’ qualifications, colleges and the length in training. The study also indicated that although professional development programmes were held, these were however not properly monitored. Findings also revealed that the intervention strategies through professional development programmes and the support given by the district and the schools were strategies through professional development programmes and the support given by the district and the schools were not adequate and consistent. As a result the participants encountered a number of challenges regarding the implementation of professional development programmes for Grade R teachers. Namely: (1) lack of appropriately qualified personnel to support the teachers both at school and the district (2) lack of adequate follow up support visits and feedbacks from both the school and the district (3) lack of proper management by the schools and (4) lack of collaboration ii and team work in the schools. Thus, there were variances in schools under study especially with regards to late release of funding for teaching and learning materials, support offered to the principals by the Department of Education. As a result, recommendations from the study suggested that the Department of Education and the District have to come up with more strategies of continuously training the teachers and the principals and offering strong and adequate support. The study also recommended the engagement of NGOs for job embedded professional development with longer in-service training periods as compared to the shot in-service professional development programs of once- off workshops. Also another suggestion that the district must monitor school based professional development programs regularly was raised in the study
- Full Text:
- Date Issued: 2020
Implementation of safety measures in selected public high schools in the Alfred Nzo East education district
- Authors: Mditshwa, Simbongile
- Date: 2020
- Subjects: Schools -- Security measures School safety and security
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/17895 , vital:41975
- Description: The main aim of the study was to find out how safety measures are implemented in selected public high schools in the Alfred Nzo East Education District. The study was motivated by multiple media reports about incidents that have to do with the safety of learners especially in rural public schools. This case study was grounded in the interpretive paradigm and the qualitative approach was adopted. The study was theoretically guided by the principles from both the Street-Level Bureaucracy (SLB) and the Rational Decision Making Model (RDMM). The data was collected from three schools in the Alfred Nzo East Education District, Eastern Cape, RSA. A purposive sampling technique was utilized to choose the research participants. A total of 21 human participants were involved in interviews where two teachers per school, two learners per school, two SGB parents and a principal were interviewed. Interviews were supplemented with short observations and document analysis. The findings of the research include the following: educators get a minimal empowerment to manage school safety in terms of access to school, scholar transport and on. The researched schools had no school-based safety policies. Some of the challenges included the level of roadworthiness of the vehicles that are used to transport school children which exposes learners to a high risk and that puts more pressure on school safety. Drugs and dangerous weapons are other factors which contribute to the instability of school safety. The researcher recommended that educators should be empowered through support from the principals and from the district coordinator through frequent policy implementation conference using online platform to minimize the costs of physical conferences. I recommended that the community must be active whistle-blowers for drug smuggling because drugs in schools emanate from the communities. Indemnity forms, release forms and school-based policies must be made available for implementation and referencing purposes. Schools should establish healthy relationship with external stakeholders like traditional leaders, SAPS and the Department of Social Development to curb lack of safety in schools.
- Full Text:
- Date Issued: 2020
- Authors: Mditshwa, Simbongile
- Date: 2020
- Subjects: Schools -- Security measures School safety and security
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/17895 , vital:41975
- Description: The main aim of the study was to find out how safety measures are implemented in selected public high schools in the Alfred Nzo East Education District. The study was motivated by multiple media reports about incidents that have to do with the safety of learners especially in rural public schools. This case study was grounded in the interpretive paradigm and the qualitative approach was adopted. The study was theoretically guided by the principles from both the Street-Level Bureaucracy (SLB) and the Rational Decision Making Model (RDMM). The data was collected from three schools in the Alfred Nzo East Education District, Eastern Cape, RSA. A purposive sampling technique was utilized to choose the research participants. A total of 21 human participants were involved in interviews where two teachers per school, two learners per school, two SGB parents and a principal were interviewed. Interviews were supplemented with short observations and document analysis. The findings of the research include the following: educators get a minimal empowerment to manage school safety in terms of access to school, scholar transport and on. The researched schools had no school-based safety policies. Some of the challenges included the level of roadworthiness of the vehicles that are used to transport school children which exposes learners to a high risk and that puts more pressure on school safety. Drugs and dangerous weapons are other factors which contribute to the instability of school safety. The researcher recommended that educators should be empowered through support from the principals and from the district coordinator through frequent policy implementation conference using online platform to minimize the costs of physical conferences. I recommended that the community must be active whistle-blowers for drug smuggling because drugs in schools emanate from the communities. Indemnity forms, release forms and school-based policies must be made available for implementation and referencing purposes. Schools should establish healthy relationship with external stakeholders like traditional leaders, SAPS and the Department of Social Development to curb lack of safety in schools.
- Full Text:
- Date Issued: 2020
Implementing active surveillance for TB—The views of managers in a resource limited setting, South Africa
- Febisola I. AjuduaID, Robert J. MashID
- Authors: Febisola I. AjuduaID , Robert J. MashID
- Date: 2020
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/11260/4433 , vital:44118
- Full Text:
- Authors: Febisola I. AjuduaID , Robert J. MashID
- Date: 2020
- Language: English
- Type: Journal article
- Identifier: http://hdl.handle.net/11260/4433 , vital:44118
- Full Text:
Implementing active surveillance for TB—The views of managers in a resource limited setting, South Africa
- Febisola I. AjuduaID, Robert J. MashID
- Authors: Febisola I. AjuduaID , Robert J. MashID
- Date: 2020
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/11260/4088 , vital:44022
- Full Text:
- Authors: Febisola I. AjuduaID , Robert J. MashID
- Date: 2020
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/11260/4088 , vital:44022
- Full Text:
Implementing prolonged exposure therapy for PTSD in a context of ongoing adversity: a clinical case study
- Booysen, Duane D, Kagee, Ashraf
- Authors: Booysen, Duane D , Kagee, Ashraf
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149275 , vital:38821 , https://0-doi.org.wam.seals.ac.za/10.1177/1534650120925918
- Description: Obstacles regarding the implementation of empirically supported treatments (ESTs) for mental disorders such as post-traumatic stress disorder (PTSD) still require further investigation. One notable obstacle is whether persons in low- and middle-income countries (LMICs) residing in a context of ongoing adversity would benefit from an EST for PTSD. We reflect on the utility of a brief prolonged exposure intervention at a primary care community-counseling center in South Africa. “Sam,” a 45-year-old, female was assessed at baseline, during treatment, postassessment, and at 3-month follow-up. At the beginning of treatment, Sam had a positive diagnosis for PTSD (PSSI-5 = 55, and cutoff is 23) and at the end of treatment (PSSI-5 = 17), and 3-month follow-up (PSSI-5 = 21), she had a negative diagnosis for PTSD. We reflect on the mediating effects that contextual factors such as gang violence had on the treatment process and the feasibility of implementing ESTs for PTSD in LMICs under conditions of ongoing adversity.
- Full Text:
- Date Issued: 2020
- Authors: Booysen, Duane D , Kagee, Ashraf
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149275 , vital:38821 , https://0-doi.org.wam.seals.ac.za/10.1177/1534650120925918
- Description: Obstacles regarding the implementation of empirically supported treatments (ESTs) for mental disorders such as post-traumatic stress disorder (PTSD) still require further investigation. One notable obstacle is whether persons in low- and middle-income countries (LMICs) residing in a context of ongoing adversity would benefit from an EST for PTSD. We reflect on the utility of a brief prolonged exposure intervention at a primary care community-counseling center in South Africa. “Sam,” a 45-year-old, female was assessed at baseline, during treatment, postassessment, and at 3-month follow-up. At the beginning of treatment, Sam had a positive diagnosis for PTSD (PSSI-5 = 55, and cutoff is 23) and at the end of treatment (PSSI-5 = 17), and 3-month follow-up (PSSI-5 = 21), she had a negative diagnosis for PTSD. We reflect on the mediating effects that contextual factors such as gang violence had on the treatment process and the feasibility of implementing ESTs for PTSD in LMICs under conditions of ongoing adversity.
- Full Text:
- Date Issued: 2020
Improved Stability of Rifampicin in the Presence of Gastric-Resistant Isoniazid Microspheres in Acidic Media
- Mwila, Chiluba, Walker, Roderick B
- Authors: Mwila, Chiluba , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183210 , vital:43929 , xlink:href="https://doi.org/10.3390/pharmaceutics12030234"
- Description: The degradation of rifampicin (RIF) in an acidic medium to form 3-formyl rifamycin SV, a poorly absorbed compound, is accelerated in the presence of isoniazid, contributing to the poor bioavailability of rifampicin. This manuscript presents a novel approach in which isoniazid is formulated into gastric-resistant sustained-release microspheres and RIF into microporous floating sustained-release microspheres to reduce the potential for interaction between RIF and isoniazid (INH) in an acidic environment. Hydroxypropyl methylcellulose acetate succinate and Eudragit® L100 polymers were used for the manufacture of isoniazid-loaded gastric-resistant sustained-release microspheres using an o/o solvent emulsification evaporation approach. Microporous floating sustained-release microspheres for the delivery of rifampicin in the stomach were manufactured using emulsification and a diffusion/evaporation process. The design of experiments was used to evaluate the impact of input variables on predefined responses or quality attributes of the microspheres. The percent degradation of rifampicin following 12 h dissolution testing in 0.1 M HCl pH 1.2 in the presence of isoniazid gastric-resistant sustained-release microspheres was only 4.44%. These results indicate that the degradation of rifampicin in the presence of isoniazid in acidic media can be reduced by encapsulation of both active pharmaceutical ingredients to ensure release in different segments of the gastrointestinal tract, potentially improving the bioavailability of rifampicin.
- Full Text:
- Date Issued: 2020
- Authors: Mwila, Chiluba , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183210 , vital:43929 , xlink:href="https://doi.org/10.3390/pharmaceutics12030234"
- Description: The degradation of rifampicin (RIF) in an acidic medium to form 3-formyl rifamycin SV, a poorly absorbed compound, is accelerated in the presence of isoniazid, contributing to the poor bioavailability of rifampicin. This manuscript presents a novel approach in which isoniazid is formulated into gastric-resistant sustained-release microspheres and RIF into microporous floating sustained-release microspheres to reduce the potential for interaction between RIF and isoniazid (INH) in an acidic environment. Hydroxypropyl methylcellulose acetate succinate and Eudragit® L100 polymers were used for the manufacture of isoniazid-loaded gastric-resistant sustained-release microspheres using an o/o solvent emulsification evaporation approach. Microporous floating sustained-release microspheres for the delivery of rifampicin in the stomach were manufactured using emulsification and a diffusion/evaporation process. The design of experiments was used to evaluate the impact of input variables on predefined responses or quality attributes of the microspheres. The percent degradation of rifampicin following 12 h dissolution testing in 0.1 M HCl pH 1.2 in the presence of isoniazid gastric-resistant sustained-release microspheres was only 4.44%. These results indicate that the degradation of rifampicin in the presence of isoniazid in acidic media can be reduced by encapsulation of both active pharmaceutical ingredients to ensure release in different segments of the gastrointestinal tract, potentially improving the bioavailability of rifampicin.
- Full Text:
- Date Issued: 2020
In vitro anti-cancer efficacy and phyto-chemical screening of solvent extracts of Kigelia africana (Lam.) Benth
- Mukavi, Justus W, Mayeku, Philip W, Nyaga, Justine M, Kituyi, Sarah N
- Authors: Mukavi, Justus W , Mayeku, Philip W , Nyaga, Justine M , Kituyi, Sarah N
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429439 , vital:72610 , xlink:href="https://www.cell.com/heliyon/pdf/S2405-8440(20)31325-6.pdf"
- Description: Kigelia africana is a medicinal plant growing naturally in many parts of Africa. In Kenya, a water concoction of the plant is used to treat breast and prostate cancers. Laboratory data on its anti-cancer activity and active principles is limited, hence no scientific rationale for its medicinal use. This study reports on in-vitro toxic activities of dichloromethane and methanol extracts of the plant against human breast cancer cells and phytochemical screening of the two extracts.
- Full Text:
- Date Issued: 2020
- Authors: Mukavi, Justus W , Mayeku, Philip W , Nyaga, Justine M , Kituyi, Sarah N
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429439 , vital:72610 , xlink:href="https://www.cell.com/heliyon/pdf/S2405-8440(20)31325-6.pdf"
- Description: Kigelia africana is a medicinal plant growing naturally in many parts of Africa. In Kenya, a water concoction of the plant is used to treat breast and prostate cancers. Laboratory data on its anti-cancer activity and active principles is limited, hence no scientific rationale for its medicinal use. This study reports on in-vitro toxic activities of dichloromethane and methanol extracts of the plant against human breast cancer cells and phytochemical screening of the two extracts.
- Full Text:
- Date Issued: 2020
In vitro antimicrobial photodynamic inactivation of multidrugresistant Acinetobacter baumannii biofilm using Protoporphyrin IX and Methylene blue
- Anane, Yaw Adjei, Apalata, Teke, Vasaikar, Sandeep, Okuthe, Grace Emily, Songca, Sandile Phinda
- Authors: Anane, Yaw Adjei , Apalata, Teke , Vasaikar, Sandeep , Okuthe, Grace Emily , Songca, Sandile Phinda
- Date: 2020
- Language: English
- Identifier: http://hdl.handle.net/11260/2273 , vital:41315
- Full Text:
- Authors: Anane, Yaw Adjei , Apalata, Teke , Vasaikar, Sandeep , Okuthe, Grace Emily , Songca, Sandile Phinda
- Date: 2020
- Language: English
- Identifier: http://hdl.handle.net/11260/2273 , vital:41315
- Full Text:
In Vitro Release Testing (IVRT) of Topical Hydrocortisone Acetate Creams: a novel approach using positive and negative controls
- Mudyahoto, Nyengeterai Amanda, Rath, Seeprarani, Ramanah, Ashmita, Kanfer, Isadore
- Authors: Mudyahoto, Nyengeterai Amanda , Rath, Seeprarani , Ramanah, Ashmita , Kanfer, Isadore
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149849 , vital:38888 , dx.doi.org/10.14227/DT270120P6
- Description: The objective was to develop and validate an in vitro release testing (IVRT) method to assess the release of hydrocortisone acetate (HCA) from five topical formulations. A marketed generic cream containing 1% HCA was used as the reference product. Vertical diffusion cells (VDCs) were used to assess and compare the release rates of HCA from cream formulations containing 0.5%, 1%, and 1.5% HCA. The study describes a novel approach to test the discriminatory power by including both positive and negative controls to declare pharmaceutical equivalence or inequivalence. The validated method was found to be sensitive, linear, precise, reproducible, robust, and selective for the analysis of HCA from topical cream products. Equivalence or inequivalence was established based on SUPAC-SS acceptance criteria using a 90% CI with limits of 75–133.33%. The IVRT method was shown to have discriminatory ability to appropriately measure significant differences in drug release from various cream formulations. This approach also provides useful information for the future development of acceptable IVRT methods to assess topical dosage forms for local action containing different drugs.
- Full Text:
- Date Issued: 2020
- Authors: Mudyahoto, Nyengeterai Amanda , Rath, Seeprarani , Ramanah, Ashmita , Kanfer, Isadore
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149849 , vital:38888 , dx.doi.org/10.14227/DT270120P6
- Description: The objective was to develop and validate an in vitro release testing (IVRT) method to assess the release of hydrocortisone acetate (HCA) from five topical formulations. A marketed generic cream containing 1% HCA was used as the reference product. Vertical diffusion cells (VDCs) were used to assess and compare the release rates of HCA from cream formulations containing 0.5%, 1%, and 1.5% HCA. The study describes a novel approach to test the discriminatory power by including both positive and negative controls to declare pharmaceutical equivalence or inequivalence. The validated method was found to be sensitive, linear, precise, reproducible, robust, and selective for the analysis of HCA from topical cream products. Equivalence or inequivalence was established based on SUPAC-SS acceptance criteria using a 90% CI with limits of 75–133.33%. The IVRT method was shown to have discriminatory ability to appropriately measure significant differences in drug release from various cream formulations. This approach also provides useful information for the future development of acceptable IVRT methods to assess topical dosage forms for local action containing different drugs.
- Full Text:
- Date Issued: 2020
In Vitro Studies on Antioxidant and AntiParasitic Activities of Compounds Isolated from Rauvolfia caffra Sond
- Tlhapi, Dorcas B, Ramaite, Isaiah D, Anokwuru, Chinedu P, van Ree, Teunis, Hoppe, Heinrich C
- Authors: Tlhapi, Dorcas B , Ramaite, Isaiah D , Anokwuru, Chinedu P , van Ree, Teunis , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425993 , vital:72305 , xlink:href="https://doi.org/10.3390/molecules25173781"
- Description: As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.
- Full Text:
- Date Issued: 2020
- Authors: Tlhapi, Dorcas B , Ramaite, Isaiah D , Anokwuru, Chinedu P , van Ree, Teunis , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425993 , vital:72305 , xlink:href="https://doi.org/10.3390/molecules25173781"
- Description: As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.
- Full Text:
- Date Issued: 2020
In vitro susceptibility of Staphylococcus aureus to porphyrin-silver mediated photodynamic antimicrobial chemotherapy
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
Inclusion in organisations following disability
- Authors: Durrheim, Zenita Beth
- Date: 2020
- Subjects: People with disabilities -- Employment -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/47818 , vital:40380
- Description: Given the prevalence of disability in South Africa and specifically amongst the working population, this study explores the experiences of individuals who have been rendered disabled following injury and have returned to work. This study used a qualitative research design, specifically from an interpretative perspective to gain an understanding of individuals’ experiences of inclusion in organisations following disability due to injury. The phenomenological approach was best suited to this study in terms of its provision of valuable data collection directly from the participants, based on their own unique experiences. The research methodology was based on a multiple case study approach. Semi-structured interviews were conducted with 11 identified participants through purposive sampling. Through thematic analysis, five themes of inclusion were identified including ‘supportive relationships’, ‘organisational support, accommodation and policies’, ‘nature of the working environment’, ‘work ability and financial implications’ and finally ‘personal well-being’. Furthermore, for each of the primary themes, 12 sub-themes were identified. These themes and sub-themes were explored in relation to participant experiences of inclusion as well as linking specific literature of inclusion, return-to-work and disability models to the themes presented. Linking the findings to existing theoretical models of inclusion provided context with many of the themes identified also evident within the theoretical models. The factors identified within the themes of inclusion were conceptualised at different systemic levels with eight factors identified at the macro-organisational level, nine factors at the meso-group level and eight factors at the micro-group level. These identified factors could aid organisations and policymakers to ensure the effective inclusion of individuals with disabilities in organisations.
- Full Text:
- Date Issued: 2020
- Authors: Durrheim, Zenita Beth
- Date: 2020
- Subjects: People with disabilities -- Employment -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/47818 , vital:40380
- Description: Given the prevalence of disability in South Africa and specifically amongst the working population, this study explores the experiences of individuals who have been rendered disabled following injury and have returned to work. This study used a qualitative research design, specifically from an interpretative perspective to gain an understanding of individuals’ experiences of inclusion in organisations following disability due to injury. The phenomenological approach was best suited to this study in terms of its provision of valuable data collection directly from the participants, based on their own unique experiences. The research methodology was based on a multiple case study approach. Semi-structured interviews were conducted with 11 identified participants through purposive sampling. Through thematic analysis, five themes of inclusion were identified including ‘supportive relationships’, ‘organisational support, accommodation and policies’, ‘nature of the working environment’, ‘work ability and financial implications’ and finally ‘personal well-being’. Furthermore, for each of the primary themes, 12 sub-themes were identified. These themes and sub-themes were explored in relation to participant experiences of inclusion as well as linking specific literature of inclusion, return-to-work and disability models to the themes presented. Linking the findings to existing theoretical models of inclusion provided context with many of the themes identified also evident within the theoretical models. The factors identified within the themes of inclusion were conceptualised at different systemic levels with eight factors identified at the macro-organisational level, nine factors at the meso-group level and eight factors at the micro-group level. These identified factors could aid organisations and policymakers to ensure the effective inclusion of individuals with disabilities in organisations.
- Full Text:
- Date Issued: 2020
Incorporating geomorphic knowledge in the management of wetlands in Africa’s drylands: a rapid assessment of the Kafue Wetland
- Lidzhegu, Z, Ellery, William F N, Mantel, Sukhmani
- Authors: Lidzhegu, Z , Ellery, William F N , Mantel, Sukhmani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157108 , vital:40087 , https://doi.org/10.1007/s13157-019-01172-9
- Description: Limited knowledge of wetland geomorphic processes often results in poor wetland management. This study aims to illustrate the importance of incorporating geomorphic knowledge of wetland origin in their management. The geomorphic origin and dynamics of the Kafue wetland were determined from the analysis of remotely sensed and geological data. The wetland is a remnant of a paleo-lake that was captured by the tributary of the middle Zambezi River. At the point of capture, resistant Muva Group metavolcanic rocks dominate narrow valleys characterised by straight channels. The resistant lithology prevents the lower Kafue River to cut into the wetland thus maintaining wetland conditions upstream. Sedimentation regime through overbank and bed deposits shaped the wetland’s structure, ecological diversity, and hydrological functioning. The operation of the Itezhi-tezhi dam has negatively impacted the wetland’s hydrological and sedimentological regime. The dam starves the system of sediment needed for promoting levee and channel bed aggradation. Regulated discharge with reduced sediment load can lead to channel incision and therefore reduce flood frequency, which may ultimately lead to wetland desiccation.
- Full Text:
- Date Issued: 2020
- Authors: Lidzhegu, Z , Ellery, William F N , Mantel, Sukhmani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157108 , vital:40087 , https://doi.org/10.1007/s13157-019-01172-9
- Description: Limited knowledge of wetland geomorphic processes often results in poor wetland management. This study aims to illustrate the importance of incorporating geomorphic knowledge of wetland origin in their management. The geomorphic origin and dynamics of the Kafue wetland were determined from the analysis of remotely sensed and geological data. The wetland is a remnant of a paleo-lake that was captured by the tributary of the middle Zambezi River. At the point of capture, resistant Muva Group metavolcanic rocks dominate narrow valleys characterised by straight channels. The resistant lithology prevents the lower Kafue River to cut into the wetland thus maintaining wetland conditions upstream. Sedimentation regime through overbank and bed deposits shaped the wetland’s structure, ecological diversity, and hydrological functioning. The operation of the Itezhi-tezhi dam has negatively impacted the wetland’s hydrological and sedimentological regime. The dam starves the system of sediment needed for promoting levee and channel bed aggradation. Regulated discharge with reduced sediment load can lead to channel incision and therefore reduce flood frequency, which may ultimately lead to wetland desiccation.
- Full Text:
- Date Issued: 2020
Increasing temperatures increase the risk of reproductive failure in a near threatened alpine groundnesting bird, the Cape Rockjumper Chaetops frenatus:
- Oswald, Krista N, Diener, Elizabeth F, Diener, John P, Cunningham, Susan J, Smit, Ben, Lee, Alan T K
- Authors: Oswald, Krista N , Diener, Elizabeth F , Diener, John P , Cunningham, Susan J , Smit, Ben , Lee, Alan T K
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149324 , vital:38825 , https://0-doi.org.wam.seals.ac.za/10.1111/ibi.12846
- Description: A major cause of reproductive failure in birds is nest predation. Predation risk depends on predator type, as predators vary in their ecology and sensory modalities (e.g. visual vs. olfactory). Snakes (generally olfactory predators) are a major nest predator for small birds, with predation strongly associated with higher temperatures. We investigated nest survival in a ground‐nesting alpine species, the Cape Rockjumper Chaetops frenatus , endemic to alpine fynbos in southwestern South Africa. We collected 3 years of nest data, testing whether nest survival was related to (1) habitat stage (early post‐fire vs. late post‐fire habitat, ≤ 3 and > 3 years since fire respectively), (2) nest concealment and (3) temperature. We found that nests had better survival at lower temperatures, with snake predation (our main source of predation) increasing in higher temperatures.
- Full Text:
- Date Issued: 2020
- Authors: Oswald, Krista N , Diener, Elizabeth F , Diener, John P , Cunningham, Susan J , Smit, Ben , Lee, Alan T K
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149324 , vital:38825 , https://0-doi.org.wam.seals.ac.za/10.1111/ibi.12846
- Description: A major cause of reproductive failure in birds is nest predation. Predation risk depends on predator type, as predators vary in their ecology and sensory modalities (e.g. visual vs. olfactory). Snakes (generally olfactory predators) are a major nest predator for small birds, with predation strongly associated with higher temperatures. We investigated nest survival in a ground‐nesting alpine species, the Cape Rockjumper Chaetops frenatus , endemic to alpine fynbos in southwestern South Africa. We collected 3 years of nest data, testing whether nest survival was related to (1) habitat stage (early post‐fire vs. late post‐fire habitat, ≤ 3 and > 3 years since fire respectively), (2) nest concealment and (3) temperature. We found that nests had better survival at lower temperatures, with snake predation (our main source of predation) increasing in higher temperatures.
- Full Text:
- Date Issued: 2020