Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza
- Nokelainen, Ossi, Ripley, Bradford Sherman, Van Bergen, Erik, Osborne, Colin P, Brakefield, Paul M
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
Recommendations for the future of recreational fisheries to prepare the social‐ecological system to cope with change
- Arlinghaus, Robert, Cooke, Steven J, Sutton, S G, Danylchuk, A J, Potts, Warren M, Freire, K D M, Alós, J, Da Silva, E T, Cowx, Ian G, Van Anrooy, R
- Authors: Arlinghaus, Robert , Cooke, Steven J , Sutton, S G , Danylchuk, A J , Potts, Warren M , Freire, K D M , Alós, J , Da Silva, E T , Cowx, Ian G , Van Anrooy, R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125810 , vital:35819 , https://doi.10.1111/fme.12191
- Description: This paper presents conclusions and recommendations that emerged from the 7th World Recreational Fishing Conference (WRFC) held in Campinas, Brazil in September 2014. Based on the recognition of the immense social and economic importance of recreational fisheries coupled with weaknesses in robust information about these fisheries in many areas of the world, particularly in many economies in transition, it is recommended to increase effort to build effective governance arrangements and improve monitoring and assessment frameworks in data-poor situations. Moreover, there is a need to increase interdisciplinary studies that will foster a systematic understanding of recreational fisheries as complex adaptive social-ecological systems. To promote sustainable recreational fisheries on a global scale, it is recommended the detailed suggestions for governance and management outlined in the United Nations Food and Agricultural Organization Technical Guidelines for Responsible Fisheries: Recreational Fisheries are followed.
- Full Text:
- Date Issued: 2016
- Authors: Arlinghaus, Robert , Cooke, Steven J , Sutton, S G , Danylchuk, A J , Potts, Warren M , Freire, K D M , Alós, J , Da Silva, E T , Cowx, Ian G , Van Anrooy, R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125810 , vital:35819 , https://doi.10.1111/fme.12191
- Description: This paper presents conclusions and recommendations that emerged from the 7th World Recreational Fishing Conference (WRFC) held in Campinas, Brazil in September 2014. Based on the recognition of the immense social and economic importance of recreational fisheries coupled with weaknesses in robust information about these fisheries in many areas of the world, particularly in many economies in transition, it is recommended to increase effort to build effective governance arrangements and improve monitoring and assessment frameworks in data-poor situations. Moreover, there is a need to increase interdisciplinary studies that will foster a systematic understanding of recreational fisheries as complex adaptive social-ecological systems. To promote sustainable recreational fisheries on a global scale, it is recommended the detailed suggestions for governance and management outlined in the United Nations Food and Agricultural Organization Technical Guidelines for Responsible Fisheries: Recreational Fisheries are followed.
- Full Text:
- Date Issued: 2016
SASO and Black Consciousness, and the shift to congress politics
- Authors: Badat, Saleem
- Date: 2016
- Language: English
- Type: book chapter , text
- Identifier: http://hdl.handle.net/10962/59755 , vital:27645 , http://witspress.co.za/catalogue/students-must-rise/
- Description: Students Must Rise 98 Chapter 8 SASO and Black Consciousness, and the shift to congress politics I n 1960, demonstrators protesting against pass laws were killed and injured by police at Sharpeville. Soon afterwards, the apartheid government declared a state of emergency. Over 11 000 political activists were detained, and repressive new laws, police raids, arrests, bannings, and torture were used to crush political opposition to apartheid. The African National Congress (ANC) and Pan Africanist Congress (PAC) were banned, and many leaders of the ANC and PAC were arrested and imprisoned , and hundreds fled into exile. For many white South Africans, the rest of the 1960s were a time of economic boom, political calm, prosperity, and rising living standards. Some blacks took the opportunity to accumulate wealth, power, and privilege through the Bantustans that the apartheid government established as part of its separate development programme. For most blacks, it was a period of great economic exploitation, extensive political and social control, fear, and demoralisation. It was difficult to see how there could be any political challenge to white minority rule. Anti-apartheid organisations faced immediate repression. They also had to overcome black people’s fear and demoralisation, which stood in the way of mobilising opposition against apartheid. The emergence of the South African Students’ Organisation and Black Consciousness Despite many problems, the South African Students’ Organisation (SASO) was formed as an exclusively black university and college student organisation in 1968. It escaped immediate state repression, and developed a following among students at the Saleem Badat SASO and Black Consciousness, and the shift to congress politics 99 universities reserved for blacks. Thereafter, the ideology of Black Consciousness (BC) was developed and other BC organisations were formed, resulting in the BC movement. SASO saw its challenge as the ‘assertion, manifestation and development of a sense of awareness politically, socially and economically among the black community’.1 It emphasised black ‘group cohesion and solidarity’ as ‘important facets of Black Consciousness’, the need for ‘the totality of involvement of the oppressed people’, and for BC ‘to be spread to reach all sections of the black community’.2 SASO began community development, literacy, education, media, culture, and sports projects, which aimed to help black communities to determine and realise their own needs. They were seen as a means to win the trust of people and to educate and mobilise them.3 Projects instilled the idea of self-reliance, seen as important for achieving freedom, in members and communities. SASO created a favourable political climate for various organisations to emerge.
- Full Text: false
- Date Issued: 2016
- Authors: Badat, Saleem
- Date: 2016
- Language: English
- Type: book chapter , text
- Identifier: http://hdl.handle.net/10962/59755 , vital:27645 , http://witspress.co.za/catalogue/students-must-rise/
- Description: Students Must Rise 98 Chapter 8 SASO and Black Consciousness, and the shift to congress politics I n 1960, demonstrators protesting against pass laws were killed and injured by police at Sharpeville. Soon afterwards, the apartheid government declared a state of emergency. Over 11 000 political activists were detained, and repressive new laws, police raids, arrests, bannings, and torture were used to crush political opposition to apartheid. The African National Congress (ANC) and Pan Africanist Congress (PAC) were banned, and many leaders of the ANC and PAC were arrested and imprisoned , and hundreds fled into exile. For many white South Africans, the rest of the 1960s were a time of economic boom, political calm, prosperity, and rising living standards. Some blacks took the opportunity to accumulate wealth, power, and privilege through the Bantustans that the apartheid government established as part of its separate development programme. For most blacks, it was a period of great economic exploitation, extensive political and social control, fear, and demoralisation. It was difficult to see how there could be any political challenge to white minority rule. Anti-apartheid organisations faced immediate repression. They also had to overcome black people’s fear and demoralisation, which stood in the way of mobilising opposition against apartheid. The emergence of the South African Students’ Organisation and Black Consciousness Despite many problems, the South African Students’ Organisation (SASO) was formed as an exclusively black university and college student organisation in 1968. It escaped immediate state repression, and developed a following among students at the Saleem Badat SASO and Black Consciousness, and the shift to congress politics 99 universities reserved for blacks. Thereafter, the ideology of Black Consciousness (BC) was developed and other BC organisations were formed, resulting in the BC movement. SASO saw its challenge as the ‘assertion, manifestation and development of a sense of awareness politically, socially and economically among the black community’.1 It emphasised black ‘group cohesion and solidarity’ as ‘important facets of Black Consciousness’, the need for ‘the totality of involvement of the oppressed people’, and for BC ‘to be spread to reach all sections of the black community’.2 SASO began community development, literacy, education, media, culture, and sports projects, which aimed to help black communities to determine and realise their own needs. They were seen as a means to win the trust of people and to educate and mobilise them.3 Projects instilled the idea of self-reliance, seen as important for achieving freedom, in members and communities. SASO created a favourable political climate for various organisations to emerge.
- Full Text: false
- Date Issued: 2016
Seeing yourself in a new light: crossing the threshold to “researcher"
- Authors: Clarence, Sherran
- Date: 2016
- Language: English
- Type: book chapter , text
- Identifier: http://hdl.handle.net/10962/61390 , vital:28021 , http://www.africansunmedia.co.za/Sun-e-Shop/tabid/78/ProductId/385/Default.aspx , http://dx.doi.org/10.17613/M6WW52
- Description: Writing, and the thinking, reading and analytical process that writers engage with to make writing possible, is transformative, and doctoral students in the social sciences especially tend to write themselves into their new identities as ‘doctors’ and recognised researchers. Much has been written in recent years about doctoral writing, including many advice books on how to write a ‘big-book’ or similar doctoral thesis into being. While some of the journal articles and books are helpful, and provide useful accounts of the complex challenges of writing a doctoral thesis, many of the advice books in particular focus more on the text itself, with the writer oddly under-accounted for. Recent research on, for example, doctoral writing groups and doctoral identity speaks into this gap helpfully, but much of it is written in contexts other than South Africa, and much of it is written for rather than by students going through or having recently completed a PhD process. This chapter contributes to a growing body of research and reflection on the role of writing itself in the process of becoming a ‘doctor’. Building on relevant blog posts and critical reflection through a research journal on my own transformative doctoral writing process at a South African university, this chapter will reflect on how challenging yet also potentially thrilling the writing process can be during a PhD. Readers will hopefully find in this chapter useful insights into their own process of becoming a doctor, and ideas for making their own ‘writing and becoming’ process more engaging and rewarding.
- Full Text: false
- Date Issued: 2016
- Authors: Clarence, Sherran
- Date: 2016
- Language: English
- Type: book chapter , text
- Identifier: http://hdl.handle.net/10962/61390 , vital:28021 , http://www.africansunmedia.co.za/Sun-e-Shop/tabid/78/ProductId/385/Default.aspx , http://dx.doi.org/10.17613/M6WW52
- Description: Writing, and the thinking, reading and analytical process that writers engage with to make writing possible, is transformative, and doctoral students in the social sciences especially tend to write themselves into their new identities as ‘doctors’ and recognised researchers. Much has been written in recent years about doctoral writing, including many advice books on how to write a ‘big-book’ or similar doctoral thesis into being. While some of the journal articles and books are helpful, and provide useful accounts of the complex challenges of writing a doctoral thesis, many of the advice books in particular focus more on the text itself, with the writer oddly under-accounted for. Recent research on, for example, doctoral writing groups and doctoral identity speaks into this gap helpfully, but much of it is written in contexts other than South Africa, and much of it is written for rather than by students going through or having recently completed a PhD process. This chapter contributes to a growing body of research and reflection on the role of writing itself in the process of becoming a ‘doctor’. Building on relevant blog posts and critical reflection through a research journal on my own transformative doctoral writing process at a South African university, this chapter will reflect on how challenging yet also potentially thrilling the writing process can be during a PhD. Readers will hopefully find in this chapter useful insights into their own process of becoming a doctor, and ideas for making their own ‘writing and becoming’ process more engaging and rewarding.
- Full Text: false
- Date Issued: 2016
What lies beneath: exploring the deeper purposes of feedback on student writing through considering disciplinary knowledge and knowers
- Van Heerden, Martina, Clarence, Sherran, Bharuthram, Sharita
- Authors: Van Heerden, Martina , Clarence, Sherran , Bharuthram, Sharita
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59856 , vital:27669 , https://doi.org/10.1080/02602938.2016.1212985
- Description: Feedback plays an integral role in students’ learning and development, as it is often the only personal communication that students have with tutors or lecturers about their own work. Yet, in spite of its integral role in student learning, there is disagreement between how students and tutors or lecturers perceive the pedagogic purpose of feedback. Central to this disagreement is the role that feedback has to play in ensuring that students produce the ‘right’ kinds of knowledge, and become the ‘right’ kinds of knowers within their disciplines. This paper argues that, in order to find common ground between students and tutors or lecturers on what feedback is for, and how to both give and use it effectively, we need to conceptualise disciplinary knowledge and knowers anew. We offer, as a useful starting point, the Specialisation dimension of Legitimation Code Theory as both practical theory and methodological tool for exploring knowledge and knowers in English Studies and Law as two illustrative cases. The paper concludes that this analysis offers lecturers and tutors a fresh understanding of the disciplinary knowledge and knower structures they work within and, relatedly, a clearer view of the work their feedback needs to do within these.
- Full Text: false
- Date Issued: 2016
- Authors: Van Heerden, Martina , Clarence, Sherran , Bharuthram, Sharita
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59856 , vital:27669 , https://doi.org/10.1080/02602938.2016.1212985
- Description: Feedback plays an integral role in students’ learning and development, as it is often the only personal communication that students have with tutors or lecturers about their own work. Yet, in spite of its integral role in student learning, there is disagreement between how students and tutors or lecturers perceive the pedagogic purpose of feedback. Central to this disagreement is the role that feedback has to play in ensuring that students produce the ‘right’ kinds of knowledge, and become the ‘right’ kinds of knowers within their disciplines. This paper argues that, in order to find common ground between students and tutors or lecturers on what feedback is for, and how to both give and use it effectively, we need to conceptualise disciplinary knowledge and knowers anew. We offer, as a useful starting point, the Specialisation dimension of Legitimation Code Theory as both practical theory and methodological tool for exploring knowledge and knowers in English Studies and Law as two illustrative cases. The paper concludes that this analysis offers lecturers and tutors a fresh understanding of the disciplinary knowledge and knower structures they work within and, relatedly, a clearer view of the work their feedback needs to do within these.
- Full Text: false
- Date Issued: 2016
'Meaningful engagement’: Towards a language rights paradigm for effective language policy implementation
- Docrat, Zakeera, Kaschula, Russell H
- Authors: Docrat, Zakeera , Kaschula, Russell H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174812 , vital:42512 , https://doi.org/10.1080/02572117.2015.1056455
- Description: This article aims to develop the concept of ‘meaningful engagement’ in terms of the contemporary language policy implementation framework in South Africa. By exploring the current language policies, implementation and the current lack of effectiveness, the authors offer a new implementation focus drawn from the legal concept of ‘meaningful engagement’. ‘Meaningful engagement’ is a concept within the socio-economic rights sphere. This article expands and advances the concept within a language policy framework. Against the enabling legislative environment created by the Use of Official Languages Act 12 of 2012 and the overarching Constitutional framework which embeds the rights of all official languages, ‘meaningful engagement’ is developed and applied to selected language policies and practices.
- Full Text:
- Date Issued: 2015
- Authors: Docrat, Zakeera , Kaschula, Russell H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174812 , vital:42512 , https://doi.org/10.1080/02572117.2015.1056455
- Description: This article aims to develop the concept of ‘meaningful engagement’ in terms of the contemporary language policy implementation framework in South Africa. By exploring the current language policies, implementation and the current lack of effectiveness, the authors offer a new implementation focus drawn from the legal concept of ‘meaningful engagement’. ‘Meaningful engagement’ is a concept within the socio-economic rights sphere. This article expands and advances the concept within a language policy framework. Against the enabling legislative environment created by the Use of Official Languages Act 12 of 2012 and the overarching Constitutional framework which embeds the rights of all official languages, ‘meaningful engagement’ is developed and applied to selected language policies and practices.
- Full Text:
- Date Issued: 2015
Anton and Vale van der Merwe: reinterpreting Afro-Oriental studio ceramics traditions in South Africa
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/968 , vital:30077
- Description: Growing awareness of ancient Chinese Song and Yuan ceramics, amongst other Oriental traditions, by people with western connections such as Bernard Leach and Michael Cardew, in conjunction with influences from Japanese associates such as Soyetsu Yanagi, Kenkichi Tomimoto, and Shoji Hamada, (De Waal 1997, Harrod 2012, Kikuchi 1977, Leach 1976) has had many consequences. It spread a consciousness idealizing self-sufficient pottery studios where potters were in touch with all aspects of creating utilityware, largely from local materials for local use. Out of this emerged an Anglo-Oriental studio ceramic philosophy of form and practice, associated mainly with hand-made high temperature reduction fired ceramics. These ideas spread to South Africa in the late 1950s, and by the early 1960s local studios were being established along these lines. This studio ceramics movement grew exponentially in South Africa, initiating a phase of Afro-Oriental ceramics that remains a powerful way of life and visual arts influence. This paper seeks to explore aspects of Afro- Oriental studio ceramics in South Africa, with particular reference to the Leach/Hamada/Cardew to Rabinowitz, and Van der Merwe lineage.
- Full Text:
- Date Issued: 2015
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/968 , vital:30077
- Description: Growing awareness of ancient Chinese Song and Yuan ceramics, amongst other Oriental traditions, by people with western connections such as Bernard Leach and Michael Cardew, in conjunction with influences from Japanese associates such as Soyetsu Yanagi, Kenkichi Tomimoto, and Shoji Hamada, (De Waal 1997, Harrod 2012, Kikuchi 1977, Leach 1976) has had many consequences. It spread a consciousness idealizing self-sufficient pottery studios where potters were in touch with all aspects of creating utilityware, largely from local materials for local use. Out of this emerged an Anglo-Oriental studio ceramic philosophy of form and practice, associated mainly with hand-made high temperature reduction fired ceramics. These ideas spread to South Africa in the late 1950s, and by the early 1960s local studios were being established along these lines. This studio ceramics movement grew exponentially in South Africa, initiating a phase of Afro-Oriental ceramics that remains a powerful way of life and visual arts influence. This paper seeks to explore aspects of Afro- Oriental studio ceramics in South Africa, with particular reference to the Leach/Hamada/Cardew to Rabinowitz, and Van der Merwe lineage.
- Full Text:
- Date Issued: 2015
Being a Born Free: the misunderstandings and missed opportunities facing young South Africans
- Authors: Malila, Vanessa
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158680 , vital:40220 , https://hdl.handle.net/10520/EJC175765
- Description: Young South Africans are often referred to as the Born Frees - a term which sometimes means people born after 1994, sometimes people born after 1990, or young people who came of age politically after 1994. I've come to really dislike the term Born Frees and particularly the way it is used by the media and the politicians. By calling young people Born Frees, society is using apartheid as a reference point to identify a post-apartheid generation. This reference point (the transition to a 'free' society) unfortunately does not resonate with many of the young people that I've encountered in my research and many feel insulted by the implications of this term, which does not apply to them in any way. Should South African society really be using the transition from apartheid to define its young people and how does it relate to the lives of real young people in South Africa today? Are they really Born Free, free from what, free to do what, free individuals or free as a collective? I will look at some of the stereotypes being used in the mainstream media of Born Frees, and then look at the reaction to this term by some real young South Africans.
- Full Text:
- Date Issued: 2015
- Authors: Malila, Vanessa
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158680 , vital:40220 , https://hdl.handle.net/10520/EJC175765
- Description: Young South Africans are often referred to as the Born Frees - a term which sometimes means people born after 1994, sometimes people born after 1990, or young people who came of age politically after 1994. I've come to really dislike the term Born Frees and particularly the way it is used by the media and the politicians. By calling young people Born Frees, society is using apartheid as a reference point to identify a post-apartheid generation. This reference point (the transition to a 'free' society) unfortunately does not resonate with many of the young people that I've encountered in my research and many feel insulted by the implications of this term, which does not apply to them in any way. Should South African society really be using the transition from apartheid to define its young people and how does it relate to the lives of real young people in South Africa today? Are they really Born Free, free from what, free to do what, free individuals or free as a collective? I will look at some of the stereotypes being used in the mainstream media of Born Frees, and then look at the reaction to this term by some real young South Africans.
- Full Text:
- Date Issued: 2015
Brown hyena habitat selection varies among sites in a semi-arid region of southern Africa
- Welch, Rebecca J, Tambling, Craig J, Bissett, Charlene, Gaylard, Angela, Müller, Konrad, Slater, Kerry, Strauss, W Maartin, Parker, Daniel M
- Authors: Welch, Rebecca J , Tambling, Craig J , Bissett, Charlene , Gaylard, Angela , Müller, Konrad , Slater, Kerry , Strauss, W Maartin , Parker, Daniel M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123277 , vital:35423 , https://doi.10.1093/jmammal/gyv189
- Description: In the last 50 years, the human impact on ecosystems has been greater than during any other time period in human history (Millennium Ecosystem Assessment 2003). Large carnivores face anthropogenic threats worldwide, specifically persecution, habitat degradation, and habitat fragmentation (Everatt et al. 2014; Groom et al. 2014; Ripple et al. 2014; Wolfe et al. 2015). Because large carnivores often occupy high trophic levels, their presence influences species at lower levels through trophic cascades (Ripple et al. 2014). Natural experiments, taking advantage of large carnivore management, have shown that large predators provide fundamental ecosystem and economic services that help maintain healthy and diverse ecosystems (Ripple et al. 2014). Additionally, carnivores play an important role in other ecosystem processes, for example, scavenging carnivores may provide regulatory services, such as waste removal, nutrient cycling, and disease regulation. Such services add stability to ecosystems and ensure energy flow through multiple trophic levels (DeVault et al. 2003; Wilson and Wolkovich 2011).
- Full Text:
- Date Issued: 2015
- Authors: Welch, Rebecca J , Tambling, Craig J , Bissett, Charlene , Gaylard, Angela , Müller, Konrad , Slater, Kerry , Strauss, W Maartin , Parker, Daniel M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123277 , vital:35423 , https://doi.10.1093/jmammal/gyv189
- Description: In the last 50 years, the human impact on ecosystems has been greater than during any other time period in human history (Millennium Ecosystem Assessment 2003). Large carnivores face anthropogenic threats worldwide, specifically persecution, habitat degradation, and habitat fragmentation (Everatt et al. 2014; Groom et al. 2014; Ripple et al. 2014; Wolfe et al. 2015). Because large carnivores often occupy high trophic levels, their presence influences species at lower levels through trophic cascades (Ripple et al. 2014). Natural experiments, taking advantage of large carnivore management, have shown that large predators provide fundamental ecosystem and economic services that help maintain healthy and diverse ecosystems (Ripple et al. 2014). Additionally, carnivores play an important role in other ecosystem processes, for example, scavenging carnivores may provide regulatory services, such as waste removal, nutrient cycling, and disease regulation. Such services add stability to ecosystems and ensure energy flow through multiple trophic levels (DeVault et al. 2003; Wilson and Wolkovich 2011).
- Full Text:
- Date Issued: 2015
Deposition of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shells around CdSeTe alloyed core quantum dots: effects on optical properties
- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:7289 , http://hdl.handle.net/10962/d1020342
- Description: In this work, we synthesized water-soluble L-cysteine-capped alloyed CdSeTe core quantum dots (QDs) and investigated the structural and optical properties of deposition of each of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shell layers. Photophysical results showed that the overcoating of a CdS shell around the alloyed CdSeTe core [quantum yield (QY) = 8.4%] resulted in effective confinement of the radiative exciton with an improved QY value of 93.5%. Subsequent deposition of a ZnSe shell around the CdSeTe/CdS surface decreased the QY value to 24.7%, but an increase in the QY value of up to 49.5% was observed when a ZnS shell was overcoated around the CdSeTe/CdS/ZnSe surface. QDs with shell layers showed improved stability relative to the core. Data obtained from time-resolved fluorescence measurements provided useful insight into variations in the photophysical properties of the QDs upon the formation of each shell layer. Our study suggests that the formation of CdSeTe/CdS core/shell QDs meets the requirements of quality QDs in terms of high photoluminescence QY and stability, hence further deposition of additional shells are not necessary in improving the optical properties of the core/shell QDs. Copyright © 2015 John Wiley & Sons, Ltd. , Original publication is available at http://dx.doi.org/10.1002/bio.3013
- Full Text: false
- Date Issued: 2015
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:7289 , http://hdl.handle.net/10962/d1020342
- Description: In this work, we synthesized water-soluble L-cysteine-capped alloyed CdSeTe core quantum dots (QDs) and investigated the structural and optical properties of deposition of each of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shell layers. Photophysical results showed that the overcoating of a CdS shell around the alloyed CdSeTe core [quantum yield (QY) = 8.4%] resulted in effective confinement of the radiative exciton with an improved QY value of 93.5%. Subsequent deposition of a ZnSe shell around the CdSeTe/CdS surface decreased the QY value to 24.7%, but an increase in the QY value of up to 49.5% was observed when a ZnS shell was overcoated around the CdSeTe/CdS/ZnSe surface. QDs with shell layers showed improved stability relative to the core. Data obtained from time-resolved fluorescence measurements provided useful insight into variations in the photophysical properties of the QDs upon the formation of each shell layer. Our study suggests that the formation of CdSeTe/CdS core/shell QDs meets the requirements of quality QDs in terms of high photoluminescence QY and stability, hence further deposition of additional shells are not necessary in improving the optical properties of the core/shell QDs. Copyright © 2015 John Wiley & Sons, Ltd. , Original publication is available at http://dx.doi.org/10.1002/bio.3013
- Full Text: false
- Date Issued: 2015
Fish predation regimes modify benthic diatom community structures: experimental evidence from an in situ mesocosm study
- Wasserman, Ryan J, Vink, Tim J F, Dalu, Tatenda, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Dalu, Tatenda , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68052 , vital:29190 , https://doi.org/10.1111/aec.12255
- Description: Publisher version , Diatoms are important primary producers in shallow water environments. Few studies have assessed the importance of biological interactions in structuring these communities. In the present study, benthic diatom community structure in relation to manipulated food webs was assessed using in situ mesocosms, whereby predator-free environments and environments comprising two different fish species were assessed. Zooplankton abundance, settled algal biomass and the diatom community were monitored over a 12‐day period across each of the three trophic scenarios. Differences among treatments over time were observed in zooplankton abundances, particularly copepods. Similarly, the benthic diatom community structure changed significantly over time across the three trophic treatments. However, no differences in total algal biomass were found among treatments. This was likely the result of non‐diatom phytoplankton contributions. We propose that the benthic diatom community structure within the mesocosms was influenced by trophic cascades and potentially through direct consumption by the fish. The study highlights that not only are organisms at the base of the food web affected by predators at the top of the food web, but that predator identity is potentially an important consideration for predator–prey interaction outcomes with consequences for multiple trophic levels.
- Full Text: false
- Date Issued: 2015
- Authors: Wasserman, Ryan J , Vink, Tim J F , Dalu, Tatenda , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68052 , vital:29190 , https://doi.org/10.1111/aec.12255
- Description: Publisher version , Diatoms are important primary producers in shallow water environments. Few studies have assessed the importance of biological interactions in structuring these communities. In the present study, benthic diatom community structure in relation to manipulated food webs was assessed using in situ mesocosms, whereby predator-free environments and environments comprising two different fish species were assessed. Zooplankton abundance, settled algal biomass and the diatom community were monitored over a 12‐day period across each of the three trophic scenarios. Differences among treatments over time were observed in zooplankton abundances, particularly copepods. Similarly, the benthic diatom community structure changed significantly over time across the three trophic treatments. However, no differences in total algal biomass were found among treatments. This was likely the result of non‐diatom phytoplankton contributions. We propose that the benthic diatom community structure within the mesocosms was influenced by trophic cascades and potentially through direct consumption by the fish. The study highlights that not only are organisms at the base of the food web affected by predators at the top of the food web, but that predator identity is potentially an important consideration for predator–prey interaction outcomes with consequences for multiple trophic levels.
- Full Text: false
- Date Issued: 2015
Historical demography of southern African patellid limpets: congruence of population expansions, but not phylogeography
- Mmonwa, Kolobe L, Teske, Peter R, McQuaid, Christopher D, Barker, Nigel P
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444814 , vital:74300 , https://doi.org/10.2989/1814232X.2015.1009165
- Description: Global climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum. Such expansions and the ability of species to colonise new habitats will influence their genetic structure, but the link between scales of larval dispersal and the strength of phylogeographic structure is not always clear. We analysed a fragment of the mitochondrial COI gene of 11 sympatric species of intertidal southern African patellid limpets to investigate how ancient oceanographic dynamics have shaped and maintained their contemporary spatial genetic variation. Our data show that the patellid limpets investigated display congruent evidence of spatial expansion during the Late Pleistocene or Early Holocene, which corresponds with the establishment of the contemporary southern African shoreline. We argue that closely related and co-distributed southern African intertidal invertebrates responded to ancient climatic oscillations as a cohesive group. In contrast, contemporary oceanographic circulation has shaped the phylogeographic patterns of these limpets in different ways. We show close relationships between phylogeography and biogeography for some species, but not for others, despite the similarities in their life histories and exposure to the same climatic changes.
- Full Text:
- Date Issued: 2015
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444814 , vital:74300 , https://doi.org/10.2989/1814232X.2015.1009165
- Description: Global climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum. Such expansions and the ability of species to colonise new habitats will influence their genetic structure, but the link between scales of larval dispersal and the strength of phylogeographic structure is not always clear. We analysed a fragment of the mitochondrial COI gene of 11 sympatric species of intertidal southern African patellid limpets to investigate how ancient oceanographic dynamics have shaped and maintained their contemporary spatial genetic variation. Our data show that the patellid limpets investigated display congruent evidence of spatial expansion during the Late Pleistocene or Early Holocene, which corresponds with the establishment of the contemporary southern African shoreline. We argue that closely related and co-distributed southern African intertidal invertebrates responded to ancient climatic oscillations as a cohesive group. In contrast, contemporary oceanographic circulation has shaped the phylogeographic patterns of these limpets in different ways. We show close relationships between phylogeography and biogeography for some species, but not for others, despite the similarities in their life histories and exposure to the same climatic changes.
- Full Text:
- Date Issued: 2015
Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system
- Sloterdijk, Hans, James, Nicola C, Smith, M Kyle S, Ekau, Werner, Weyl, Olaf L F
- Authors: Sloterdijk, Hans , James, Nicola C , Smith, M Kyle S , Ekau, Werner , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443919 , vital:74171 , https://doi.org/10.1080/15627020.2015.1021169
- Description: This study investigates the distribution, relative abundance, population growth and biology of the alien invasive fish Gambusia affinis in the Wilderness Lakes System, a coastal lake system in the warm-temperate region of South Africa. Fish were collected throughout the system during four seasonal sampling trips in spring (October 2010), summer (February 2011), autumn (May 2011) and winter (July 2011). Gambusia affinis were widespread and abundant in all habitats from the freshwater reaches of the inflowing Touw River to the more saline lakes and estuary. Sex ratio was generally female dominated and mean length at maturity was 14.7 mm standard length (SL) for males and 20.3 mm SL for females. Reproduction was strongly seasonal with reproductively active fish sampled in spring and summer but not in autumn and winter. Relative abundance also varied seasonally, with populations following typical ‘boom and bust’ population dynamics. By winter, the population in all habitats was lower with mortality rates as high as 85%. The stronghold of the population appears to be in the channels between the lakes, where relative abundance was more consistent and winter mortality rates were lower. The survivors, which are primarily females, then reconstitute the population in the spring and summer months.
- Full Text:
- Date Issued: 2015
- Authors: Sloterdijk, Hans , James, Nicola C , Smith, M Kyle S , Ekau, Werner , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443919 , vital:74171 , https://doi.org/10.1080/15627020.2015.1021169
- Description: This study investigates the distribution, relative abundance, population growth and biology of the alien invasive fish Gambusia affinis in the Wilderness Lakes System, a coastal lake system in the warm-temperate region of South Africa. Fish were collected throughout the system during four seasonal sampling trips in spring (October 2010), summer (February 2011), autumn (May 2011) and winter (July 2011). Gambusia affinis were widespread and abundant in all habitats from the freshwater reaches of the inflowing Touw River to the more saline lakes and estuary. Sex ratio was generally female dominated and mean length at maturity was 14.7 mm standard length (SL) for males and 20.3 mm SL for females. Reproduction was strongly seasonal with reproductively active fish sampled in spring and summer but not in autumn and winter. Relative abundance also varied seasonally, with populations following typical ‘boom and bust’ population dynamics. By winter, the population in all habitats was lower with mortality rates as high as 85%. The stronghold of the population appears to be in the channels between the lakes, where relative abundance was more consistent and winter mortality rates were lower. The survivors, which are primarily females, then reconstitute the population in the spring and summer months.
- Full Text:
- Date Issued: 2015
Standard Practices
- Amendt, Jens, Anderson, G, Campobasso, Carlo P, Dadour, I R, Gaudry, E, Hall, Martin J R, Moretti, T C, Sukontason, K L, Villet, Martin H
- Authors: Amendt, Jens , Anderson, G , Campobasso, Carlo P , Dadour, I R , Gaudry, E , Hall, Martin J R , Moretti, T C , Sukontason, K L , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442821 , vital:74036 , ISBN , https://www.routledge.com/Forensic-Entomology-International-Dimensions-and-Frontiers/Tomberlin-Benbow/p/book/9780367575885
- Description: The use of forensic entomology has become established as a global science. Recent efforts in the field bridge multiple disciplines including, but not limited to, microbiology, chemistry, genetics, and systematics as well as ecology and evolution. The first book of its kind, Forensic Entomology: International Dimensions and Frontiers provides an inclusive summary of worldwide research on this body of knowledge that integrates aspects of a wide range of scientific realms. The book first reviews the history of forensic entomology, its accomplishments, and future challenges in nations around the world. It then provides perspectives of other scientific disciplines that are shaping the questions being addressed in the field.
- Full Text:
- Date Issued: 2015
- Authors: Amendt, Jens , Anderson, G , Campobasso, Carlo P , Dadour, I R , Gaudry, E , Hall, Martin J R , Moretti, T C , Sukontason, K L , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442821 , vital:74036 , ISBN , https://www.routledge.com/Forensic-Entomology-International-Dimensions-and-Frontiers/Tomberlin-Benbow/p/book/9780367575885
- Description: The use of forensic entomology has become established as a global science. Recent efforts in the field bridge multiple disciplines including, but not limited to, microbiology, chemistry, genetics, and systematics as well as ecology and evolution. The first book of its kind, Forensic Entomology: International Dimensions and Frontiers provides an inclusive summary of worldwide research on this body of knowledge that integrates aspects of a wide range of scientific realms. The book first reviews the history of forensic entomology, its accomplishments, and future challenges in nations around the world. It then provides perspectives of other scientific disciplines that are shaping the questions being addressed in the field.
- Full Text:
- Date Issued: 2015
An Interview with Ken Barris:
- Authors: Marais, Mike
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144050 , vital:38306 , DOI: 10.4314/eia.v41i1.9
- Description: Ken Barris was born in Port Elizabeth and lives in Cape Town, where he works at the Cape Peninsula University of Technology. His writing includes two collections of poetry, a collection of short stories, and five novels, the most recent being What Kind of Child (2006) and Life Underwater (2012). His work has been translated into Turkish, Danish, German and Slovenian, and poetry and short fiction have appeared in various anthologies. More recently, he has turned to writing for academic journals. His research interests are postapartheid fiction and language education.
- Full Text:
- Date Issued: 2014
- Authors: Marais, Mike
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144050 , vital:38306 , DOI: 10.4314/eia.v41i1.9
- Description: Ken Barris was born in Port Elizabeth and lives in Cape Town, where he works at the Cape Peninsula University of Technology. His writing includes two collections of poetry, a collection of short stories, and five novels, the most recent being What Kind of Child (2006) and Life Underwater (2012). His work has been translated into Turkish, Danish, German and Slovenian, and poetry and short fiction have appeared in various anthologies. More recently, he has turned to writing for academic journals. His research interests are postapartheid fiction and language education.
- Full Text:
- Date Issued: 2014
Behavior of Palladium Nanoparticles in the Absence or Presence of Cobalt Tetraaminophthalocyanine for the Electrooxidation of Hydrazine
- Maringa, Audacity, Nyokong, Tebello
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
- Full Text: false
- Date Issued: 2014
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
- Full Text: false
- Date Issued: 2014
Bioinformatics education—perspectives and challenges out of Africa
- Tastan Bishop, Özlem, Adebiyi, Ezekiel F, Alzohairy, Ahmed M, Everett, Dean B, Ghedira, Kais, Ghouila, Amel, Kumuthini, Judit, Mulder, Nicola J, Panji, Sumir, Patterton, Hugh-G
- Authors: Tastan Bishop, Özlem , Adebiyi, Ezekiel F , Alzohairy, Ahmed M , Everett, Dean B , Ghedira, Kais , Ghouila, Amel , Kumuthini, Judit , Mulder, Nicola J , Panji, Sumir , Patterton, Hugh-G
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123244 , vital:35420 , https://doi.10.1093/bib/bbu022
- Description: The discipline of bioinformatics has developed rapidly since the complete sequencing of the first genomes in the 1990s.The development of many high-throughput techniques during the last decades has ensured that bioinformatics has grown into a discipline that overlaps with, and is required for, the modern practice of virtually every field in the life sciences. This has placed a scientific premium on the availability of skilled bioinformaticians, a qualification that is extremely scarce on the African continent. The reasons for this are numerous, although the absence of a skilled bioinformatician at academic institutions to initiate a training process and build sustained capacity seems to be a common African shortcoming.This dearth of bioinformatics expertise has had a knock-on effect on the establishment of many modern high-throughput projects at African institutes, including the comprehensive and systematic analysis of genomes from African populations, which are among the most genetically diverse anywhere on the planet. Recent funding initiatives from the National Institutes of Health and theWellcomeTrust are aimed at ameliorating this shortcoming. In this paper, we discuss the problems that have limited the establishment of the bioinformatics field in Africa, as well as propose specific actions that will help with the education and training of bioinformaticians on the continent. This is an absolute requirement in anticipation of a boom in high-throughput approaches to human health issues unique to data from African populations.
- Full Text:
- Date Issued: 2014
- Authors: Tastan Bishop, Özlem , Adebiyi, Ezekiel F , Alzohairy, Ahmed M , Everett, Dean B , Ghedira, Kais , Ghouila, Amel , Kumuthini, Judit , Mulder, Nicola J , Panji, Sumir , Patterton, Hugh-G
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123244 , vital:35420 , https://doi.10.1093/bib/bbu022
- Description: The discipline of bioinformatics has developed rapidly since the complete sequencing of the first genomes in the 1990s.The development of many high-throughput techniques during the last decades has ensured that bioinformatics has grown into a discipline that overlaps with, and is required for, the modern practice of virtually every field in the life sciences. This has placed a scientific premium on the availability of skilled bioinformaticians, a qualification that is extremely scarce on the African continent. The reasons for this are numerous, although the absence of a skilled bioinformatician at academic institutions to initiate a training process and build sustained capacity seems to be a common African shortcoming.This dearth of bioinformatics expertise has had a knock-on effect on the establishment of many modern high-throughput projects at African institutes, including the comprehensive and systematic analysis of genomes from African populations, which are among the most genetically diverse anywhere on the planet. Recent funding initiatives from the National Institutes of Health and theWellcomeTrust are aimed at ameliorating this shortcoming. In this paper, we discuss the problems that have limited the establishment of the bioinformatics field in Africa, as well as propose specific actions that will help with the education and training of bioinformaticians on the continent. This is an absolute requirement in anticipation of a boom in high-throughput approaches to human health issues unique to data from African populations.
- Full Text:
- Date Issued: 2014
Can δ15N and δ13C stable isotopes and fatty acid signatures indicate changes in phytobenthos composition on an artificial substrate?
- Dalu, Tatenda, Froneman, P William
- Authors: Dalu, Tatenda , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68086 , vital:29197 , https://doi.org/10.2989/16085914.2014.974018
- Description: Publisher version , Temporal changes in fatty acid composition and δ15N, δ13C stable isotope values of the phytobenthos growing on artificial clay substrates under natural conditions over a 28-day period at an upstream and a downstream site in the Kowie River near Grahamstown were investigated in 2012. High concentrations of diatom markers 16:1ω7 and 20:5ω3 fatty acids were recorded, especially at the downstream site, reflecting the importance of diatoms in contributing to the phytobenthos communities at that station. After day 7 at the downstream site the average δ15N value of the phytobenthos was lighter, gradually increasing by ∼2‰ and ∼5‰ overall to heavier values on day 28. At the upstream site there were no significant changes (<1‰ increase) in δ15N values of the phytobenthos over time. Stable nitrogen (δ15N) and carbon (δ13C) signatures in the phytobenthos communities were significantly different between sites (one-way ANOVA; p < 0.001). The stable isotope values and fatty acid concentrations of phytobenthos at the downstream site were different to those of the phytobenthos at the upstream site, and they changed concurrently with changes in the phytobenthos community structure. At the downstream site there was a strong correlation of the δ15N of phytobenthos with nitrates (R = 0.56) and time (weeks; R = 0.81). However, the fatty acids were not specific enough to characterise the composition of phytobenthos communities. Other biomarker methods, such as stable isotopes and microscopic examination of the communities, were found to be useful. The results from this relatively small-scale tile experiment indicate the complexity of changes in fatty acid composition and δ15N, δ13C stable isotope values of a phytobenthos community. Stable isotope and fatty acid composition can be successfully used to map changes in phytobenthos composition and carbon and nitrogen flow patterns along a river continuum.
- Full Text: false
- Date Issued: 2014
- Authors: Dalu, Tatenda , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68086 , vital:29197 , https://doi.org/10.2989/16085914.2014.974018
- Description: Publisher version , Temporal changes in fatty acid composition and δ15N, δ13C stable isotope values of the phytobenthos growing on artificial clay substrates under natural conditions over a 28-day period at an upstream and a downstream site in the Kowie River near Grahamstown were investigated in 2012. High concentrations of diatom markers 16:1ω7 and 20:5ω3 fatty acids were recorded, especially at the downstream site, reflecting the importance of diatoms in contributing to the phytobenthos communities at that station. After day 7 at the downstream site the average δ15N value of the phytobenthos was lighter, gradually increasing by ∼2‰ and ∼5‰ overall to heavier values on day 28. At the upstream site there were no significant changes (<1‰ increase) in δ15N values of the phytobenthos over time. Stable nitrogen (δ15N) and carbon (δ13C) signatures in the phytobenthos communities were significantly different between sites (one-way ANOVA; p < 0.001). The stable isotope values and fatty acid concentrations of phytobenthos at the downstream site were different to those of the phytobenthos at the upstream site, and they changed concurrently with changes in the phytobenthos community structure. At the downstream site there was a strong correlation of the δ15N of phytobenthos with nitrates (R = 0.56) and time (weeks; R = 0.81). However, the fatty acids were not specific enough to characterise the composition of phytobenthos communities. Other biomarker methods, such as stable isotopes and microscopic examination of the communities, were found to be useful. The results from this relatively small-scale tile experiment indicate the complexity of changes in fatty acid composition and δ15N, δ13C stable isotope values of a phytobenthos community. Stable isotope and fatty acid composition can be successfully used to map changes in phytobenthos composition and carbon and nitrogen flow patterns along a river continuum.
- Full Text: false
- Date Issued: 2014
Colonisation and community structure of benthic diatoms on artificial substrates following a major flood event: a case of the Kowie River (Eastern Cape, South Africa)
- Dalu, Tatenda, Froneman, P William, Chari, Lenin D, Richoux, Nicole B
- Authors: Dalu, Tatenda , Froneman, P William , Chari, Lenin D , Richoux, Nicole B
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143357 , vital:38239 , http://dx.doi.org/10.4314/wsa.v40i3.10
- Description: A major flooding event that occurred during October–November 2012 caused major changes in the Kowie River hydromorphology and aquatic communities. The aim of our study was to identify the environmental variables that structure riverine benthic diatom communities at upstream and downstream locations 25 km apart on the Kowie River, South Africa. This was undertaken using tiles as artificial substrates so that we could study how the communities developed after the flood disturbance. The diatom community structure was assessed over a 28-day period following a flood event in October 2012. The Mann Whitney test indicated that there was a statistically significant difference (p 0.05) in total dissolved solids, salinity, pH and oxygen reduction potential between the two sites. In total, 58 diatom species belonging to 30 genera were identified over the 28-day study.
- Full Text:
- Date Issued: 2014
- Authors: Dalu, Tatenda , Froneman, P William , Chari, Lenin D , Richoux, Nicole B
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143357 , vital:38239 , http://dx.doi.org/10.4314/wsa.v40i3.10
- Description: A major flooding event that occurred during October–November 2012 caused major changes in the Kowie River hydromorphology and aquatic communities. The aim of our study was to identify the environmental variables that structure riverine benthic diatom communities at upstream and downstream locations 25 km apart on the Kowie River, South Africa. This was undertaken using tiles as artificial substrates so that we could study how the communities developed after the flood disturbance. The diatom community structure was assessed over a 28-day period following a flood event in October 2012. The Mann Whitney test indicated that there was a statistically significant difference (p 0.05) in total dissolved solids, salinity, pH and oxygen reduction potential between the two sites. In total, 58 diatom species belonging to 30 genera were identified over the 28-day study.
- Full Text:
- Date Issued: 2014
Cracks in reproductive health rights: knowledge of abortion legislation stipulations amongst learners in Buffalo City, South Africa
- Macleod, Catriona I, Seutlwadi, Lebogang, Steele, Gary I
- Authors: Macleod, Catriona I , Seutlwadi, Lebogang , Steele, Gary I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6296 , http://hdl.handle.net/10962/d1014772
- Description: Background: The Choice on Termination of Pregnancy (CTOP) Act legalised abortion on request in South Africa until up to 12 weeks of gestation and thereafter under specified conditions. Within the context of liberal legislation, accurate information is a necessary (although not sufficient) requirement for women to exercise their reproductive rights. Objectives: This research investigated Grade 11 learners’ knowledge of the CTOP Act and its stipulations. Methods: Survey research was conducted with respondents drawn from a range of schools in Buffalo City, South Africa. Multi-stage sampling was used, namely stratified random sampling of schools and purposive sampling of grades used within schools. The data were collected by means of self-administered questionnaires in group situations. Results: Results indicate that knowledge of the legal status of abortion, as well as of the various stipulations of the law, was poor. Various misunderstandings were evident, including that spousal approval is required in order for married women to have an abortion. Significant differences between the knowledge of respondents at the various schools were found, with those learners attending schools formerly designated for African learners during Apartheid having the least knowledge. Conclusion: Given the multiple factors that may serve as barriers to women accessing abortion, it is imperative that at least the most fundamental aspect of reproductive rights, that is, the right to information, is not undermined.
- Full Text:
- Date Issued: 2014
- Authors: Macleod, Catriona I , Seutlwadi, Lebogang , Steele, Gary I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6296 , http://hdl.handle.net/10962/d1014772
- Description: Background: The Choice on Termination of Pregnancy (CTOP) Act legalised abortion on request in South Africa until up to 12 weeks of gestation and thereafter under specified conditions. Within the context of liberal legislation, accurate information is a necessary (although not sufficient) requirement for women to exercise their reproductive rights. Objectives: This research investigated Grade 11 learners’ knowledge of the CTOP Act and its stipulations. Methods: Survey research was conducted with respondents drawn from a range of schools in Buffalo City, South Africa. Multi-stage sampling was used, namely stratified random sampling of schools and purposive sampling of grades used within schools. The data were collected by means of self-administered questionnaires in group situations. Results: Results indicate that knowledge of the legal status of abortion, as well as of the various stipulations of the law, was poor. Various misunderstandings were evident, including that spousal approval is required in order for married women to have an abortion. Significant differences between the knowledge of respondents at the various schools were found, with those learners attending schools formerly designated for African learners during Apartheid having the least knowledge. Conclusion: Given the multiple factors that may serve as barriers to women accessing abortion, it is imperative that at least the most fundamental aspect of reproductive rights, that is, the right to information, is not undermined.
- Full Text:
- Date Issued: 2014