Incorporation of environmental issues in South Africa’s municipal Integrated Development Plans
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180481 , vital:43393 , xlink:href="https://doi.org/10.1080/13504509.2015.1062161"
- Description: The transition to full democracy in South Africa in 1994 saw local government becoming the focal point for dealing with socio-economic development needs of communities. The Integrated Development Plan (IDP) has been used as the tool for guiding local development objectives, balanced against environmental demands within a sustainable development paradigm. Here we examine the extent to which this is being achieved through an analysis of IDPs from 35 different municipalities at three scales. We test the hypothesis that the metropolitan municipalities are better at mainstreaming environmental issues into their IDPs than local and district municipalities. Results indicate that mainstreaming environmental issues in IDPs is still low. The hypothesis that metropoles are better at mainstreaming environmental issues than district and local municipalities was not accepted since there were no significant differences between municipalities. There was low relative budget allocations and inclusion of vision and mission statements that mainstream environmental issues in all municipalities. For mainstreaming of environmental issues to be effective in IDPs, both proactive approaches and multi-faceted bottom-up and top-down approaches are suggested.
- Full Text:
- Date Issued: 2016
Infecting the city: site-situational performance and ambulatory hermeneutics
- Authors: Simbao, Ruth K
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146156 , vital:38500 , DOI: 10.1080/09528822.2016.1266776
- Description: This article proposes the term ‘site-situational’ art or performance as a meaningful shift beyond ‘site-specificity’ and as a way to develop forward-moving and relational understandings of place. While place falls prey to Western, modernist stereotypes of closed, territorial geographic systems, site-situational readings, radical forms of ‘recognition’ and ambulatory hermeneutics enable an understanding of place as a wandering signifier, a trickster figure, and an in-the-moment conversation between environments and living beings. Through an analysis of the 2009 Infecting the City performing arts festival in South Africa, the article links site-situational performance to situational understandings of identification in the context of migration and xenophobia. It connects the participatory creative resistance aspired to by the Situationists that transforms situations rather than just recognises them, to the potential mutuality that can be experienced when one recognises oneself in the face of a ‘foreigner’ as well as the potential culpability that accompanies pro-active recognition-on-the-run.
- Full Text:
- Date Issued: 2016
Interaction of graphene quantum dots with 4-acetamido-2, 2, 6, 6-tetramethylpiperidine-oxyl free radicals
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189031 , vital:44810 , xlink:href="https://doi.org/10.1007/s10895-015-1712-0"
- Description: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidineoxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photoinduced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
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- Date Issued: 2016
Interpreting press coverage of South Africa’s post-apartheid “obesity epidemic”:
- Authors: Vincent, Louise , Malan, Chantelle
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141866 , vital:38011 , DOI: 10.1080/21604851.2015.1015397
- Description: This study examines news reporting on South Africa’s alleged “obesity” epidemic between 1997 and 2012. Results indicate that fatness is equated with disease, crisis, and dysfunction and the fat black body is singled out for particular attention as a social problem. News reporting on fat in South Africa uncritically takes up the views of sources with commercial interests who are presented as “experts” on fat. Their interpretations of the fat black body as a social problem are influenced by the imperative of new markets for products that are to be found principally in the ranks of the post-apartheid black middle class.
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- Date Issued: 2016
Intra-and inter-group perceptions of Chinese and Tanzanian employees in intercultural cooperation
- Authors: Mayer, Claude-Hélène , Boness, Christian M , Louw, Lynette , Louw, Mattheus J
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61111 , vital:27976 , http://www.up.ac.za/media/shared/643/ZP_Files/2016/Papers/hrl18_full.zp97856.pdf , ISBN 9780620717977
- Description: The cooperation between Chinese and Tanzanian employees and organisations has a very long tradition in Tanzanian history. The purpose of this paper is to explore and understand how Chinese and Tanzanian employees see themselves and “the other” while cooperating. This research presents a study of a single case, conducted in a selected Chinese organisation in Tanzania. It uses a hermeneutical research paradigm. Data was collected using semi-structured interviews and observation and analysed through content analysis, following Terre Blanche’s model. Findings demonstrate and explain the perspectives which Chinese and Tanzanian employees hold mutually with regard to the group image of self and other within the organisation, as well as perceptions of self and other in terms of organisational, environmental and cultural contexts. Since this is a qualitative single organisational case study, the findings are limited to this single organisation and are not generalisable. Conclusions drawn from the new research insights are provided and recommendations are given in terms of how Chinese and Tanzanian perceptions present themselves and how organisations could work with self-image and counter images to improve intercultural cooperation.
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- Date Issued: 2016
Introducing State of the Discipline Papers
- Authors: Macleod, Catriona I , Capdevila, Rose , Marecek, Jeanne
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446272 , vital:74486 , xlink:href="https://doi.org/10.1177/0959353516649724"
- Description: The editors of Feminism and Psychology are delighted to introduce the first of our State of the Discipline papers. Twenty-five years have passed since the establishment of FandP. Significant work in feminist psychology and in feminisms relevant to psychology has been published both in this jour-nal and in others since (and before) the establishment of FandP. The range of topics that feminists in psychology consider has expanded and the reach of feminist studies has broadened. In light of the dynamic growth of the field, we believe that the time is ripe to establish what we have termed ‘State of the Discipline’ papers. We envision this series as a collection of occasional papers pertaining to particular topics or issues. What, we ask, is the current state of a specific topic within feminisms and psychologies? The State of the Discipline papers, written by scholars with a long-standing engagement with the topic, are neither empirical articles nor literature re-views. Instead, the papers are intended to apprise readers of the current state of knowledge about the topic, drawing on the literatures of both psy-chology and feminist studies. The articles: summarise key developments; point out areas of conceptual and methodological debate among feminist scholars; open up the topic to further scrutiny and new ways of understand-ing; and promote nuanced work in the field.
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- Date Issued: 2016
Investigating multi-thread utilization as a software defence mechanism against side channel attacks
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430190 , vital:72672 , https://doi.org/10.1145/3015166.3015176
- Description: A state-of-the-art software countermeasure to defend against side channel attacks is investigated in this work. The implementation of this novel approach consists of using multi-threads and a task scheduler on a microcontroller to purposefully leak out information at critical points in the cryptographic algorithm and confuse the attacker. This research demonstrates it is capable of outperforming the known countermeasure of hiding and shuffling in terms of preventing the secret information from being leaked out. Furthermore, the proposed countermeasure mitigates the side channel attacks, such as correlation power analysis and template attacks.
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- Date Issued: 2016
Keeping it in the family: coevolution of latrunculid sponges and their dominant bacterial symbionts
- Authors: Matcher, Gwynneth F , Waterworth, Samantha C , Walmsley, Tara A , Matsatsa, Tendayi , Parker-Nance, Shirley , Davies-Coleman, Michael T , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65603 , vital:28818 , https://doi.org/10.1002/mbo3.417
- Description: publisher version , The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU0.03), while a second OTU0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites. , This research was supported by a SARChI grant from the South African National Research Foundation (NRF, GUN: 87583) and the Rhodes University Sandisa Imbewu Programme. S. C. W. was supported by an NRF Innovation PhD Scholarship and a Rhodes University Henderson PhD Scholarship. T. A. W. was supported by PhD Fellowships from the NRF and the German Academic Exchange Service (DAAD)
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- Date Issued: 2016
Knowledge and knowers in teaching and learning: an enhanced approach to curriculum alignment
- Authors: Clarence, Sherran
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59823 , vital:27655 , http://www.legitimationcodetheory.com/pdf/2016Clarence-c.pdf
- Description: John Biggs’ well-known curriculum design approach, constructive alignment, is widely used in higher education in the United Kingdom, Australia and South Africa. Developed with one dominant account of learning through curriculum, this approach has a gap in terms of accounting for other kinds of knowledge building, and associated knower development. This paper proposes a complementary approach that accounts for different kinds of knowledge and knower building. Using Legitimation Code Theory’s concept of Specialisation, the paper argues that accounting for what makes a discipline ‘special’ in terms of its basis for legitimate achievement can enable curriculum writers to align curricula more effectively with that basis in different disciplines. Using a case study approach, this paper shows how this tool can provide lecturers and academic development practitioners with a useful mode of analysing curriculum alignment to more ably account for differential development of disciplinary knowledges and knowers.
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- Date Issued: 2016
Knowledge, perceptions and willingness to control designated invasive tree species in urban household gardens in South Africa
- Authors: Shackleton, Charlie M , Shackleton, Ross T
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180445 , vital:43389 , xlink:href="https://doi.org/10.1007/s10530-016-1104-7"
- Description: Many biological invasions result in negative impacts on the environment and human livelihoods, but simultaneously some also provide benefits that are valued differently by various stakeholders. To inform policy and management of invasive species it is important to assess landowners’ and broader society’s knowledge and perceptions of invasive species, something which is lacking in many contexts, especially in urban settings. In this study we interviewed 153 householders living in a medium-sized South African town who had declared invasive alien trees in their gardens. Less than half of the respondents could identify the invasive tree on their property and only one-third knew that it was an invasive alien species. There was a positive association between income and education levels with exposure to media about invasive alien species and respondents’ ability to identify the species and name any other invasive alien tree species. Knowledge levels were unequal across species. Amongst those who knew the tree was an invasive alien species, reasons why they retained it in their gardens included that it would be costly or too much effort to remove, they liked the tree, that it was not causing any harm and that the property was rented and so its removal was not their responsibility. However, the majority of people (83 %) were willing to have it removed from their garden if done for free by appropriate agencies, which is promising for compliance with new regulations on invasive species implemented at the end of 2014 in South Africa. The results also highlight the need for targeted and appropriate education and awareness programs amongst urban householders on invasive alien species, relevant legislation and their obligations.
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- Date Issued: 2016
Listening to the ‘Born Frees’: politics and disillusionment in South Africa
- Authors: Malila, Vanessa , Garman, Anthea
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158884 , vital:40237 , https://doi.org/10.1080/23743670.2015.1084587
- Description: In 2014 South Africa celebrated 20 years of democracy, and for many of the ‘Born Frees’ – those who came of age politically after 1996 – this was their first opportunity to vote in national elections. With democracy came the promise for South Africa's marginalised majority of voice and agency, but also the implicit promise that their democratically elected government would listen to them. In addition, the South African media have long championed their role as a voice for the voiceless. This article presents work done with youngsters from South Africa's poorest province, the Eastern Cape, in an effort to listen to their experience of politics and to understand their use of the media – especially whether it enables them to speak out and be heard in the public sphere.
- Full Text:
- Date Issued: 2016
Lives "on hold": the Daily Sun and the South African identity document
- Authors: Boshoff, Priscilla A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143538 , vital:38255 , https://hdl.handle.net/10520/EJC195358
- Description: The relationship between a personal identity and the state-issued Identity Document (ID) is the focus of this article, which examines stories published in the "Horror Affairs" column of the popular South African tabloid, the Daily Sun. These highly emotional stories tell of the despair and desperation felt by individuals at the lack of an ID book, which is blamed on the inefficiency of the state Department of Home Affairs. In order to explicate this relationship I make use of Agamben's notion of "bare life" and the camp in conjunction with Lacan's idea of the Symbolic Order to argue that if the Identity Document provides the means by which the individual is made to signify, the lack of an Identity Document threatens to reduce the individual to "bare life". By publishing the stories of those deprived of the visibility that the ID provides, the Daily Sun, I show, directly engages in this exchange, and, in contrast to Home Affairs, bestows its own even stronger gift of identity by the fact of appearance in its pages.
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- Date Issued: 2016
Macroinvertebrate communities associated with duckweed (Lemnaceae) in two Eastern Cape rivers, South Africa
- Authors: Muskett, Phillippa C , Hill, Jaclyn M , Weyl, Philip S R
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444065 , vital:74182 , https://doi.org/10.2989/16085914.2016.1241173
- Description: The functional feeding groups and diversity of macroinvertebrate communities associated with duckweed mats in the New Years River (two sites) and Bloukrans River (two sites), Eastern Cape province, South Africa, were assessed. Duckweed (Lemnaceae) is a ubiquitous family of floating macrophytes. A total of 41 macroinvertebrate families were collected monthly over a six-month period from February to July 2014. Duckweed biomass in both rivers was highly variable both temporally and spatially. The majority of identified macroinvertebrate taxa were predators and detritivores, with a small percentage of herbivores. An average of approximately 26% of the macroinvertebrate taxa found were from families that include species from more than one functional feeding group. Although overall measures of diversity and ecosystem health (Fisher’s α and Simpson’s index) remained constant over time in the New Years River, significant differences in macroinvertebrate community structure were seen between sites and months on both rivers, with dissimilarity being driven by a larger number of species in the New Years River. This high variability within macroinvertebrate assemblages probably reflects a combination of heterogeneous duckweed distribution, variation in physico-chemistry, opportunistic behaviours of macroinvertebrate predators and/or successional colonisation of duckweed mats.
- Full Text:
- Date Issued: 2016
Mapping epistemic cultures and learning potential of participants in citizen science projects
- Authors: Vallabh, Priya , Lotz-Sisitka, Heila , O'Donoghue, Rob B , Schudel, Ingrid J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128939 , vital:36192 , https://doi.org/10.1111/cobi.12701
- Description: The ever-widening scope and range of global change and interconnected systemic risks arising from people–environment relationships (social‐ecological risks) appears to be increasing concern among, and involvement of, citizens in an increasingly diversified number of citizen science projects responding to these risks. We examined the relationship between epistemic cultures in citizen science projects and learning potential related to matters of concern. We then developed a typology of purposes and a citizen science epistemic‐cultures heuristic and mapped 56 projects in southern Africa using this framework. The purpose typology represents the range of knowledge‐production purposes, ranging from laboratory science to social learning, whereas the epistemic‐cultures typology is a relational representation of scientist and citizen participation and their approach to knowledge production. Results showed an iterative relationship between matters of fact and matters of concern across the projects; the nexus of citizens’ engagement in knowledge‐production activities varied. The knowledge‐production purposes informed and shaped the epistemic cultures of all the sampled citizen science projects, which in turn influenced the potential for learning within each project. Through a historical review of 3 phases in a long‐term river health‐monitoring project, we found that it is possible to evolve the learning curve of citizen science projects. This evolution involved the development of scientific water monitoring tools, the parallel development of pedagogic practices supporting monitoring activities, and situated engagement around matters of concern within social activism leading to learning‐led change. We conclude that such evolutionary processes serve to increase potential for learning and are necessary if citizen science is to contribute to wider restructuring of the epistemic culture of science under conditions of expanding social-ecological risk.
- Full Text:
- Date Issued: 2016
MARS Motif: Assessment and Ranking Suite for transcription factor binding motifs
- Authors: Kibet, Cabel K , Machanick, Philip
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439339 , vital:73568 , https://doi.org/10.1101/065615
- Description: We describe MARS (Motif Assessment and Ranking Suite), a web-based suite of tools used to evaluate and rank PWM-based motifs. The increased number of learned motif models that are spread across databases and in different PWM formats, leading to a choice dilemma among the users, is our motivation. This increase has been driven by the difficulty of modelling transcription factor binding sites and the advance in high-throughput sequencing technologies at a continually reducing cost. Therefore, several experimental techniques have been developed resulting in diverse motif-finding algorithms and databases. We collate a wide variety of available motifs into a benchmark database, including the corresponding experimental ChIP-seq and PBM data obtained from ENCODE and UniPROBE databases, respectively. The implemented tools include: a data-independent consistency-based motif assessment and ranking (CB-MAR), which is based on the idea that ‘correct motifs’ are more similar to each other while incorrect motifs will differ from each other; and a scoring and classification-based algorithms, which rank binding models by their ability to discriminate sequences known to contain binding sites from those without. The CB-MAR and scoring techniques have a 0.86 and 0.73 median rank correlation using ChIP-seq and PBM respectively. Best motifs selected by CB-MAR achieve a mean AUC of 0.75, comparable to those ranked by held out data at 0.76 – this is based on ChIP-seq motif discovery using five algorithms on 110 transcription factors. We have demonstrated the benefit of this web server in motif choice and ranking, as well as in motif discovery.
- Full Text:
- Date Issued: 2016
MARS: Motif Assessment and Ranking Suite for transcription factor binding motifs
- Authors: Kibet, Caleb K , Machanick, Philip
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61155 , vital:27985 , http://dx.doi.org/10.1101/065615
- Description: We describe MARS (Motif Assessment and Ranking Suite), a web-based suite of tools used to evaluate and rank PWM-based motifs. The increased number of learned motif models that are spread across databases and in different PWM formats, leading to a choice dilemma among the users, is our motivation. This increase has been driven by the difficulty of modelling transcription factor binding sites and the advance in high-throughput sequencing technologies at a continually reducing cost. Therefore, several experimental techniques have been developed resulting in diverse motif-finding algorithms and databases. We collate a wide variety of available motifs into a benchmark database, including the corresponding experimental ChIP-seq and PBM data obtained from ENCODE and UniPROBE databases, respectively. The implemented tools include: a data-independent consistency-based motif assessment and ranking (CB-MAR), which is based on the idea that `correct motifs' are more similar to each other while incorrect motifs will differ from each other; and a scoring and classification-based algorithms, which rank binding models by their ability to discriminate sequences known to contain binding sites from those without. The CB-MAR and scoring techniques have a 0.86 and 0.73 median rank correlation using ChIP-seq and PBM respectively. Best motifs selected by CB-MAR achieve a mean AUC of 0.75, comparable to those ranked by held out data at 0.76 { this is based on ChIP-seq motif discovery using five algorithms on 110 transcription factors. We have demonstrated the benefit of this web server in motif choice and ranking, as well as in motif.
- Full Text:
- Date Issued: 2016
MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine
- Authors: Mack, John , Mkhize, Scebi , Safonoya, Evgeniya A , Gorbunova, Yulia G , Tsivadze, Aslan Yu , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240743 , vital:50867 , xlink:href="https://doi.org/10.1142/S1088424616500322"
- Description: An analysis of the MCD spectroscopy and TD-DFT calculations of magnesium tetra-(15-crown-5-oxanthreno)-phthalocyanine is reported. This study provides a reassessment of an earlier study on the nature of the bands in UV-visible absorption spectra of magnesium and zinc tetra-(15-crown-5-oxanthreno)-phthalocyanine that was based on an analysis of TD-DFT calculations for a series of model complexes with the B3LYP functional. A detailed analysis of MCD spectral data and TD-DFT calculations with the CAM-B3LYP functional for the complete Mg(II) complex provides an additional insight into the optical properties and electronic structures of tetra-(15-crown-5-oxanthreno)-phthalocyanines. Thus, the bands in the Q-band region are reassigned as being due exclusively to the Q transition of Gouterman’s 4-orbital model, since intense pseudo-A1𝒜1 terms are observed in the MCD spectrum in a spectral region that had previously been assigned as charge transfer bands.
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- Date Issued: 2016
Modelling transport of inshore and deep-spawned chokka squid (Loligo reynaudi) paralarvae off South Africa: the potential contribution of deep spawning to recruitment
- Authors: Downey-Breedt, Nicola , Roberts, Michael J , Sauer, Warwick H H , Chang, N
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125183 , vital:35742 , https://doi.10.1111/fog.12132
- Description: The South African chokka squid, Loligo reynaudi, spawns both inshore (≤70 m) and on the mid-shelf (71–130 m) of the Eastern Agulhas Bank. The fate of these deep-spawned hatchlings and their potential contribution to recruitment is as yet unknown. Lagrangian ROMS-IBM (Regional Ocean Modelling System-Individual-Based Model) simulations confirm westward transport of inshore and deep-spawned hatchlings, but also indicate that the potential exists for paralarvae hatched on the Eastern Agulhas Bank deep spawning grounds to be removed from the shelf ecosystem. Using a ROMS-IBM, this study determined the transport and recruitment success of deepspawned hatchlings relative to inshore-hatched paralarvae. A total of 12 release sites were incorporated into the model, six inshore and six deep-spawning sites. Paralarval survival was estimated based on timely transport to nursery grounds, adequate retention within the nursery grounds and retention on the Agulhas Bank shelf. Paralarval transport and survival were dependent on both spawning location and time of hatching. Results suggest the importance of the south coast as a nursery area for inshore-hatched paralarvae, and similarly the cold ridge nursery grounds for deep-hatched paralarvae. Possible relationships between periods of highest recruitment success and spawning peaks were identified for both spawning habitats. Based on the likely autumn increase in deep spawning off the Tsitsikamma coast, and the beneficial currents during this period (as indicated by the model results) it can be concluded that deep spawning may at times contribute significantly to recruitment.
- Full Text:
- Date Issued: 2016
Molecular genetic, life-history and morphological variation in a coastal warm-temperate sciaenid fish: evidence for an upwelling-driven speciation event
- Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Santos, Carmen V D , Kruger, Jerraleigh , Thomas, Jessica A , Shaw, Paul W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125252 , vital:35750 , http://dx.doi.10.1111/jbi.12829
- Description: The marine environment is punctuated by biogeographical barriers that limit dispersal and gene flow in otherwise widespread species (Teske et al., 2011a,b; Briggs & Bowen, 2012; Luiz et al., 2012). These barriers may be physical obstacles such as landmasses (e.g. Isthmus of Panama) or less intuitive features such as deep water (Lessios et al., 2003), freshwater outflows (Floeter et al., 2008) or oceanographic features (Shaw et al., 2004; Galarza et al., 2009; von der Heyden et al., 2011). Upwelling cells and sea surface temperature (SSTs) gradients in particular are known to disrupt gene flow, leading to divergence of allopatric populations and species (Waters & Roy, 2004; Teske et al., 2011a; Henriques et al., 2012, 2014, 2015). However, as oceanographic features are seldom permanent and frequently subject to considerable environmental variability, many barriers often permit some level of permeability to dispersal (Floeter et al., 2008). Other processes may influence the persistence of differentiated allopatric taxa across such physical barriers (Bradbury et al., 2008), with ecological divergence (and diversifying selection) being reported as a major evolutionary process influencing the biogeographical distributions of marine species (Pelc et al., 2009; Teske et al., 2011a; Gaither et al., 2015).
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- Date Issued: 2016
Molecular identification of Azolla invasions in Africa: The Azolla specialist, Stenopelmus rufinasus proves to be an excellent taxonomist
- Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
- Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
- Full Text:
- Date Issued: 2016