The distribution of South African loggerhead sea turtles (Caretta caretta) as indicated by epibionts and stable isotopes
- Authors: Nolte, Christopher Robin
- Date: 2019
- Subjects: Sea turtles -- South Africa , Loggerhead turtle -- South Africa Sea turtles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/31611 , vital:31625
- Description: Many marine species undertake long-distance migrations as part of their life history strategies, and so form an important part of marine ecosystems performing a range of functions, across many habitats. However, these migratory species, including sea turtles, face multiple threats and anthropogenic impacts across their ranges and knowing their movement and distribution patterns enables more effective and appropriate conservation strategies to be devised. Satellite telemetry has provided invaluable information on spatial distribution of marine migrants, but applying this approach to a large proportion of a population is often unfeasible and costly. This study aimed to identify alternative, more cost effective methods that could assist with tracking animal movements across a larger proportion of a population of marine focal species, such as sea turtles. This study used nesting loggerhead sea turtles (Caretta caretta) from the iSimangaliso Wetland Park, South Africa as a model species to test these alternative methods and subsequently combine body condition, habitat use, and distribution range in the South West Indian Ocean. First, epibiont community assemblages were investigated as a proxy to determine sea turtle body condition. A body condition index was created using plastron shape, injuries and skin deformities. Sixty turtles were classified into four body condition categories ranging from poor to very good and this was reflected in their epibiont communities as both species abundance and richness increased with a decline in body condition. A total of twenty-eight epibiont taxa were identified from a range of systematic groups including, but not limited to, Amphipoda, Cirripedia, Brachyura and Polychaeta. The barnacle Chelonibia testudinaria showed the greatest variation among different body conditions with an increase in abundance as turtle body condition deteriorated. These results suggest that epibiont load can be used as an indicator of body condition that is easy to implement in the field. Second, a combination of organic δ13C and δ15N isotopic signatures of turtle epidermis and epibiont communities was used to infer foraging habitat. One hundred and seventy turtles were sampled for stable isotope analysis. These turtles were clustered into two groups based on δ13C at -13.61 ‰ with relative depletion or enrichment indicating foraging in oceanic or neritic environments, respectively. The epibiont communities of IV 80 turtles closely followed this cluster grouping; turtles with depleted δ13C had a higher abundance and frequency of oceanic epibiont species, such Lepas spp. Similarly, three neritic epibionts (Hyale grandicornis, Hyachelia tortugae and Podocerus africanus) were the other habitat-specific species driving community assemblages, with higher occurrence and abundance on turtles in the enriched δ13C cluster. Additionally, the size of the dietary niche was determined by a Bayesian analysis of δ13C and δ15N for 46 turtles in different body condition categories. Although there was overlap among categories, individuals in very good body condition had the smallest dietary niche. These results show the complementarity of using epibionts and stable isotope analysis in determining foraging area. Third, Chelonibia testudinaria barnacles on sea turtles were analysed for δ18O and inorganic δ13C. The δ18O of expected calcite fractionation was mapped for the known migration routes of eight turtles in the South West Indian Ocean. The inorganic carbon values were not very informative on movement, however, the δ18O analysis of the barnacle showed the range of the turtle host moving through the isoscape. Most of the turtles migrated from the north in the Mozambique Channel, to the southern rookery in South Africa, which is in accordance with reports from tag recoveries and satellite telemetry studies. Using this approach to track migratory species that have epibiotic barnacles can provide complimentary approach to satellite tracking that can be used on more individuals within a population. This study aids in providing alternative methods to study body condition, habitat use and regional movement of loggerhead sea turtles. These approaches can be applied to other sea turtle species and migratory marine fauna to help better understand their movement patterns thereby promoting more effective conservation strategies. Future work should consider incorporating different cohorts, examining other epibionts such as meiofauna and diatoms, including additional isotope and trace elements for analysis on habitat and improving the resolution of the isoscape data for δ18O of seawater in the SWIO.
- Full Text:
- Date Issued: 2019
- Authors: Nolte, Christopher Robin
- Date: 2019
- Subjects: Sea turtles -- South Africa , Loggerhead turtle -- South Africa Sea turtles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/31611 , vital:31625
- Description: Many marine species undertake long-distance migrations as part of their life history strategies, and so form an important part of marine ecosystems performing a range of functions, across many habitats. However, these migratory species, including sea turtles, face multiple threats and anthropogenic impacts across their ranges and knowing their movement and distribution patterns enables more effective and appropriate conservation strategies to be devised. Satellite telemetry has provided invaluable information on spatial distribution of marine migrants, but applying this approach to a large proportion of a population is often unfeasible and costly. This study aimed to identify alternative, more cost effective methods that could assist with tracking animal movements across a larger proportion of a population of marine focal species, such as sea turtles. This study used nesting loggerhead sea turtles (Caretta caretta) from the iSimangaliso Wetland Park, South Africa as a model species to test these alternative methods and subsequently combine body condition, habitat use, and distribution range in the South West Indian Ocean. First, epibiont community assemblages were investigated as a proxy to determine sea turtle body condition. A body condition index was created using plastron shape, injuries and skin deformities. Sixty turtles were classified into four body condition categories ranging from poor to very good and this was reflected in their epibiont communities as both species abundance and richness increased with a decline in body condition. A total of twenty-eight epibiont taxa were identified from a range of systematic groups including, but not limited to, Amphipoda, Cirripedia, Brachyura and Polychaeta. The barnacle Chelonibia testudinaria showed the greatest variation among different body conditions with an increase in abundance as turtle body condition deteriorated. These results suggest that epibiont load can be used as an indicator of body condition that is easy to implement in the field. Second, a combination of organic δ13C and δ15N isotopic signatures of turtle epidermis and epibiont communities was used to infer foraging habitat. One hundred and seventy turtles were sampled for stable isotope analysis. These turtles were clustered into two groups based on δ13C at -13.61 ‰ with relative depletion or enrichment indicating foraging in oceanic or neritic environments, respectively. The epibiont communities of IV 80 turtles closely followed this cluster grouping; turtles with depleted δ13C had a higher abundance and frequency of oceanic epibiont species, such Lepas spp. Similarly, three neritic epibionts (Hyale grandicornis, Hyachelia tortugae and Podocerus africanus) were the other habitat-specific species driving community assemblages, with higher occurrence and abundance on turtles in the enriched δ13C cluster. Additionally, the size of the dietary niche was determined by a Bayesian analysis of δ13C and δ15N for 46 turtles in different body condition categories. Although there was overlap among categories, individuals in very good body condition had the smallest dietary niche. These results show the complementarity of using epibionts and stable isotope analysis in determining foraging area. Third, Chelonibia testudinaria barnacles on sea turtles were analysed for δ18O and inorganic δ13C. The δ18O of expected calcite fractionation was mapped for the known migration routes of eight turtles in the South West Indian Ocean. The inorganic carbon values were not very informative on movement, however, the δ18O analysis of the barnacle showed the range of the turtle host moving through the isoscape. Most of the turtles migrated from the north in the Mozambique Channel, to the southern rookery in South Africa, which is in accordance with reports from tag recoveries and satellite telemetry studies. Using this approach to track migratory species that have epibiotic barnacles can provide complimentary approach to satellite tracking that can be used on more individuals within a population. This study aids in providing alternative methods to study body condition, habitat use and regional movement of loggerhead sea turtles. These approaches can be applied to other sea turtle species and migratory marine fauna to help better understand their movement patterns thereby promoting more effective conservation strategies. Future work should consider incorporating different cohorts, examining other epibionts such as meiofauna and diatoms, including additional isotope and trace elements for analysis on habitat and improving the resolution of the isoscape data for δ18O of seawater in the SWIO.
- Full Text:
- Date Issued: 2019
The relationship between attribution style, rural vs urban status and traumatic stress severity in Kiambu and Nyeri counties, Kenya
- Authors: Ndungu, Jane Wagithi
- Date: 2018
- Subjects: Post-traumatic stress disorder -- Kenya , Post-traumatic stress disorder -- Patients -- Interviews -- Kenya Rural conditions -- Psychological aspects -- Kenya Rural mental health services -- Kenya Community psychology -- Kenya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/32793 , vital:32363
- Description: Traumatic exposure and posttraumatic stress in Kenya is a common experience. Despite this prevalence, an investigation of the dynamic influence of variables (such as cultural differences) on posttraumatic stress has received little attention in the country. This means that a relatively narrow understanding of traumatic stress exists in the Kenyan context. This study therefore investigated the relationship between attribution style, rural vs. urban status and posttraumatic stress severity. The exploration and description of these relationships contributed to creating a more nuanced understanding of traumatic stress. Such a nuanced understanding would be useful to a variety of fields of practice. The study utilised a sample from a rural and urban area of Kenya. A purposive convenience sample of 178 rural and 176 urban individuals was used. The study employed a biographical questionnaire and 2 quantitative measures, namely, the Attribution Style Questionnaire (ASQ) and the PTSD Checklist for DSM-5 (PCL-5). Descriptive and inferential statistics were used to analyse the data. Results indicated that posttraumatic stress severity in the urban area was significantly higher than in the rural area. The urban sample was significantly more likely to attribute negative events to internal (rather than external) and specific (rather than global) causes than the rural sample. A regression analysis showed that a negative internal attribution style and educational level had a significant relationship with posttraumatic stress severity.
- Full Text:
- Date Issued: 2018
- Authors: Ndungu, Jane Wagithi
- Date: 2018
- Subjects: Post-traumatic stress disorder -- Kenya , Post-traumatic stress disorder -- Patients -- Interviews -- Kenya Rural conditions -- Psychological aspects -- Kenya Rural mental health services -- Kenya Community psychology -- Kenya
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/32793 , vital:32363
- Description: Traumatic exposure and posttraumatic stress in Kenya is a common experience. Despite this prevalence, an investigation of the dynamic influence of variables (such as cultural differences) on posttraumatic stress has received little attention in the country. This means that a relatively narrow understanding of traumatic stress exists in the Kenyan context. This study therefore investigated the relationship between attribution style, rural vs. urban status and posttraumatic stress severity. The exploration and description of these relationships contributed to creating a more nuanced understanding of traumatic stress. Such a nuanced understanding would be useful to a variety of fields of practice. The study utilised a sample from a rural and urban area of Kenya. A purposive convenience sample of 178 rural and 176 urban individuals was used. The study employed a biographical questionnaire and 2 quantitative measures, namely, the Attribution Style Questionnaire (ASQ) and the PTSD Checklist for DSM-5 (PCL-5). Descriptive and inferential statistics were used to analyse the data. Results indicated that posttraumatic stress severity in the urban area was significantly higher than in the rural area. The urban sample was significantly more likely to attribute negative events to internal (rather than external) and specific (rather than global) causes than the rural sample. A regression analysis showed that a negative internal attribution style and educational level had a significant relationship with posttraumatic stress severity.
- Full Text:
- Date Issued: 2018
An assessment of the implementation of employment equity: Department of Transport in the province of the Eastern Cape
- Authors: Mqingwana, Phelo Zolisa
- Date: 2015
- Subjects: Discrimination in employment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/11335 , vital:26912
- Description: During the apartheid era black people were systematically excluded from all positions of influence in the state and civil society. The majority of senior posts in government were held by whites, in particular, white males. Women and people with disabilities were similarly disadvantaged and marginalised, particularly those from black communities. With the new post-apartheid dispensation, the democratic government took a conscious decision to change that situation. It is against this background that that the Employment Equity Act (EEA) was introduced in 1998. The two main aims of the Act are: to achieve employment equity by promoting equal opportunity and fair treatment in employment through the elimination of unfair discrimination; and to implement the affirmative action measures, to redress the disadvantages in employment experienced by designated groups in order to ensure their equitable representation in all occupational categories and levels in the workforce. The implement of EEA in the Eastern Cape Department of Transport (ECDOT) has so far not been very successful as the Department still has not managed to meet the set targets. According to their Employment Equity Plan (EEP), the senior management level (SMS) is still dominated by males. Although the situation is slightly better at the middle management level, it is still far from being ideal. The lower ranks are dominated by females. With regard to people with disabilities (PWDs) the Department is still far from meeting their 2% target. The purpose of this research was to determine if the ECDOT has been able to implement the dictates of the EEA. It aims to look at ways in which the EEA can best be implemented in order to ensure that the desired results are achieved. This study was prompted by the fact that the ECDOT has not managed to reach the EEA targets in hiring people with disabilities (PDWs) and elevating women to senior positions. The study explored the views of the employees of the Department regarding the implementation of EE. It was conducted using the quantitative approach. 90 employees were asked to respond to a structured questionnaire designed by the researcher. The findings of the study indicate that although in some areas the Department has been able to successfully implement EE, issues of racial equity, diversity, infrastructure conducive for people with disabilities, recruitment practices, and management commitment still need to be improved on. The study recommends, amongst others, that managers should provide leadership in the implementation process, more recruitment sources should be explored, suitable infrastructure must be provided, diversity issues must be addressed through workshops and training sessions, employee participation needs to be ensured, and that feedback must always be provided to EE beneficiaries in order to keep make sure they remain within the organisation and continue to improve.
- Full Text:
- Date Issued: 2015
- Authors: Mqingwana, Phelo Zolisa
- Date: 2015
- Subjects: Discrimination in employment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/11335 , vital:26912
- Description: During the apartheid era black people were systematically excluded from all positions of influence in the state and civil society. The majority of senior posts in government were held by whites, in particular, white males. Women and people with disabilities were similarly disadvantaged and marginalised, particularly those from black communities. With the new post-apartheid dispensation, the democratic government took a conscious decision to change that situation. It is against this background that that the Employment Equity Act (EEA) was introduced in 1998. The two main aims of the Act are: to achieve employment equity by promoting equal opportunity and fair treatment in employment through the elimination of unfair discrimination; and to implement the affirmative action measures, to redress the disadvantages in employment experienced by designated groups in order to ensure their equitable representation in all occupational categories and levels in the workforce. The implement of EEA in the Eastern Cape Department of Transport (ECDOT) has so far not been very successful as the Department still has not managed to meet the set targets. According to their Employment Equity Plan (EEP), the senior management level (SMS) is still dominated by males. Although the situation is slightly better at the middle management level, it is still far from being ideal. The lower ranks are dominated by females. With regard to people with disabilities (PWDs) the Department is still far from meeting their 2% target. The purpose of this research was to determine if the ECDOT has been able to implement the dictates of the EEA. It aims to look at ways in which the EEA can best be implemented in order to ensure that the desired results are achieved. This study was prompted by the fact that the ECDOT has not managed to reach the EEA targets in hiring people with disabilities (PDWs) and elevating women to senior positions. The study explored the views of the employees of the Department regarding the implementation of EE. It was conducted using the quantitative approach. 90 employees were asked to respond to a structured questionnaire designed by the researcher. The findings of the study indicate that although in some areas the Department has been able to successfully implement EE, issues of racial equity, diversity, infrastructure conducive for people with disabilities, recruitment practices, and management commitment still need to be improved on. The study recommends, amongst others, that managers should provide leadership in the implementation process, more recruitment sources should be explored, suitable infrastructure must be provided, diversity issues must be addressed through workshops and training sessions, employee participation needs to be ensured, and that feedback must always be provided to EE beneficiaries in order to keep make sure they remain within the organisation and continue to improve.
- Full Text:
- Date Issued: 2015
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