A newly discovered population of the critically endangered false limpet Siphonaria compressa Allanson, 1958 (Pulmonata: Siphonariidae), with observations on its reproductive biology
- Allanson, Brian R, Herbert, D G
- Authors: Allanson, Brian R , Herbert, D G
- Date: 2005-05-23
- Language: English
- Type: Article
- Identifier: vital:6833 , http://hdl.handle.net/10962/d1007570
- Description: The endangered false limpet, Siphonaria compressa, originally described by Allanson in 1958 from Langebaan Lagoon, Saldanha, has been found living in intertidal eelgrass meadows in the embayment of the Knysna River estuary at Bollard Bay, Leisure Isle, Knysna, South Africa. This represents only the second known site of occurrence of the species. Although classified by the IUCN as critically endangered, the Knysna population is viable. , Acrobat Distiller 6.0 (Windows)
- Full Text:
- Authors: Allanson, Brian R , Herbert, D G
- Date: 2005-05-23
- Language: English
- Type: Article
- Identifier: vital:6833 , http://hdl.handle.net/10962/d1007570
- Description: The endangered false limpet, Siphonaria compressa, originally described by Allanson in 1958 from Langebaan Lagoon, Saldanha, has been found living in intertidal eelgrass meadows in the embayment of the Knysna River estuary at Bollard Bay, Leisure Isle, Knysna, South Africa. This represents only the second known site of occurrence of the species. Although classified by the IUCN as critically endangered, the Knysna population is viable. , Acrobat Distiller 6.0 (Windows)
- Full Text:
A century of Zoology and Entomology at Rhodes University, 1905 to 2005
- Hodgson, Alan N, Craig, Adrian J F K
- Authors: Hodgson, Alan N , Craig, Adrian J F K
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6922 , http://hdl.handle.net/10962/d1011905
- Description: The history of the Department of Zoology & Entomology at Rhodes University is traced from its origin with a single staff member, through the era of permanent heads of department to the present day staff. Significant achievements and developments in teaching and research are highlighted, and some anecdotal material is included.
- Full Text:
- Date Issued: 2005
- Authors: Hodgson, Alan N , Craig, Adrian J F K
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6922 , http://hdl.handle.net/10962/d1011905
- Description: The history of the Department of Zoology & Entomology at Rhodes University is traced from its origin with a single staff member, through the era of permanent heads of department to the present day staff. Significant achievements and developments in teaching and research are highlighted, and some anecdotal material is included.
- Full Text:
- Date Issued: 2005
A decision-making framework for restoring riparian zones degraded by invasive alien plants in South Africa
- Holmes, P M, Richardson, D M, Esler, K J, Witkowski, Ed T F, Fourie, S
- Authors: Holmes, P M , Richardson, D M , Esler, K J , Witkowski, Ed T F , Fourie, S
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6635 , http://hdl.handle.net/10962/d1006859
- Description: Riparian habitats in many parts of South Africa are severely degraded by invasive alien plants, especially trees. These invasions reduce water yields from catchments and affect riverine functioning and biodiversity. Initiatives are under way countrywide to clear alien plants from watercourses and surrounding catchments. Current understanding of key processes that regulate riparian functioning and define options for restoration is rudimentary. We review the impacts of riparian invasions and identify factors limiting the recovery of natural vegetation following alien clearance. We propose a framework of strategic interventions for optimizing restoration success. The framework identifies abiotic and biotic barriers to restoration at the scales of catchments and local reaches. In highly transformed catchments, interventions at the reach scale may fail if important barriers at the catchment scale are not addressed. The extent to which propagule supply and microsite conditions inhibit vegetation recovery is unknown. We also know little of the relative importance of dispersing vegetative propagules, dispersing seeds and soil-stored seed banks in vegetation dynamics, particularly after severe disturbances such as dense invasion by alien plants. The importance of geomorphological and hydrological factors in mediating recovery of riparian vegetation has not been adequately explored for all climatic areas in South Africa. More research is needed to determine the influence of different alien species and clearing treatments on the recovery of riparian vegetation. The literature strongly suggests that in highly alien-transformed catchments, the re-introduction of riparian species is required to promote recovery and suppress re-invasion. However, such interventions are unlikely to be widely implemented unless the cost: benefit ratios are favourable.
- Full Text:
- Date Issued: 2005
- Authors: Holmes, P M , Richardson, D M , Esler, K J , Witkowski, Ed T F , Fourie, S
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6635 , http://hdl.handle.net/10962/d1006859
- Description: Riparian habitats in many parts of South Africa are severely degraded by invasive alien plants, especially trees. These invasions reduce water yields from catchments and affect riverine functioning and biodiversity. Initiatives are under way countrywide to clear alien plants from watercourses and surrounding catchments. Current understanding of key processes that regulate riparian functioning and define options for restoration is rudimentary. We review the impacts of riparian invasions and identify factors limiting the recovery of natural vegetation following alien clearance. We propose a framework of strategic interventions for optimizing restoration success. The framework identifies abiotic and biotic barriers to restoration at the scales of catchments and local reaches. In highly transformed catchments, interventions at the reach scale may fail if important barriers at the catchment scale are not addressed. The extent to which propagule supply and microsite conditions inhibit vegetation recovery is unknown. We also know little of the relative importance of dispersing vegetative propagules, dispersing seeds and soil-stored seed banks in vegetation dynamics, particularly after severe disturbances such as dense invasion by alien plants. The importance of geomorphological and hydrological factors in mediating recovery of riparian vegetation has not been adequately explored for all climatic areas in South Africa. More research is needed to determine the influence of different alien species and clearing treatments on the recovery of riparian vegetation. The literature strongly suggests that in highly alien-transformed catchments, the re-introduction of riparian species is required to promote recovery and suppress re-invasion. However, such interventions are unlikely to be widely implemented unless the cost: benefit ratios are favourable.
- Full Text:
- Date Issued: 2005
A re-evaluation of plastochron index determination in peas - a case for using leaflet length
- Ade-Ademilua, Omobolanle Elizabeth, Botha, Christiaan E J
- Authors: Ade-Ademilua, Omobolanle Elizabeth , Botha, Christiaan E J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6491 , http://hdl.handle.net/10962/d1004472
- Description: The plastochron index (PI) is a measure of plant growth reports our findings on PI using the average length of and can be used to determine growth rate, based upon the first pair of leaflets on each node. Early leaflet appearance of successive leaves on the axis of the growth in peas occurs exponentially and the early plant. PI should under ideal growth conditions be a stages of growth of successive pairs of leaflets occur at regular event and should be predictable with a relatively the same relative growth rate. Given that growth of small error of a few hours. PI has been variously leaflets during early development can be measured calculated in peas, and each method reported has had successfully, we propose the use of leaflet growth as a with it a number of problems that do not allow for measure of the plastochron index in peas. Our results reasonable prediction of PI. Internode length varies suggest that plant age is best expressed using the greatly and is dependent upon the variety, which may be plastochron index, which is a measure of the time short- or long-stemmed; thus this parameter is not ideal interval between the initiations of successive events — for determining growth rate or plant age. This paper in the case of peas, of successive pairs of leaflets.
- Full Text:
- Date Issued: 2005
- Authors: Ade-Ademilua, Omobolanle Elizabeth , Botha, Christiaan E J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6491 , http://hdl.handle.net/10962/d1004472
- Description: The plastochron index (PI) is a measure of plant growth reports our findings on PI using the average length of and can be used to determine growth rate, based upon the first pair of leaflets on each node. Early leaflet appearance of successive leaves on the axis of the growth in peas occurs exponentially and the early plant. PI should under ideal growth conditions be a stages of growth of successive pairs of leaflets occur at regular event and should be predictable with a relatively the same relative growth rate. Given that growth of small error of a few hours. PI has been variously leaflets during early development can be measured calculated in peas, and each method reported has had successfully, we propose the use of leaflet growth as a with it a number of problems that do not allow for measure of the plastochron index in peas. Our results reasonable prediction of PI. Internode length varies suggest that plant age is best expressed using the greatly and is dependent upon the variety, which may be plastochron index, which is a measure of the time short- or long-stemmed; thus this parameter is not ideal interval between the initiations of successive events — for determining growth rate or plant age. This paper in the case of peas, of successive pairs of leaflets.
- Full Text:
- Date Issued: 2005
A successful cognitive-behavioural intervention that failed : a case study of adolescent conduct disorder at a school for the disadvantaged
- Mashalaba, Eugenia D, Edwards, David J A
- Authors: Mashalaba, Eugenia D , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6273 , http://hdl.handle.net/10962/d1008273
- Description: Conduct Disorder (CD) is a widespread problem in southern Africa. The aim of the study was to design, implement and evaluate a multi-modal cognitive-behavioural intervention based on treatments developed overseas, in order to investigate whether this approach can be transported to a South African school for deprived children. The target adolescent had a history of severely disruptive behaviour and was facing expulsion from a shelter for homeless children and his school. A thorough assessment served as the basis for a case formulation and treatment plan. Intervention included 23 individual sessions focussing on bereavement and the learning of self-control skills and prosocial behaviours, as well as contingency management training for school and shelter staff. Progress was tracked with a behaviour checklist completed daily by the teacher and regular interviews with school and shelter staff. After four months, the disruptive behaviour was eliminated. However, he was involved in stealing with some other learners and expelled anyway. Nevertheless the case study provides evidence for the transportability of the cognitive-behavioural approach to this kind of setting and documents the way in which a comprehensive intervention can be tailored to the needs of a child with a severely deprived background and little social support.
- Full Text:
- Date Issued: 2005
- Authors: Mashalaba, Eugenia D , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6273 , http://hdl.handle.net/10962/d1008273
- Description: Conduct Disorder (CD) is a widespread problem in southern Africa. The aim of the study was to design, implement and evaluate a multi-modal cognitive-behavioural intervention based on treatments developed overseas, in order to investigate whether this approach can be transported to a South African school for deprived children. The target adolescent had a history of severely disruptive behaviour and was facing expulsion from a shelter for homeless children and his school. A thorough assessment served as the basis for a case formulation and treatment plan. Intervention included 23 individual sessions focussing on bereavement and the learning of self-control skills and prosocial behaviours, as well as contingency management training for school and shelter staff. Progress was tracked with a behaviour checklist completed daily by the teacher and regular interviews with school and shelter staff. After four months, the disruptive behaviour was eliminated. However, he was involved in stealing with some other learners and expelled anyway. Nevertheless the case study provides evidence for the transportability of the cognitive-behavioural approach to this kind of setting and documents the way in which a comprehensive intervention can be tailored to the needs of a child with a severely deprived background and little social support.
- Full Text:
- Date Issued: 2005
A.k.a. Breyten Breytenbach : critical approaches to his writings and paintings, J.L. Coullie and J.U. Jacobs, eds. : book review
- Authors: Vorster, Anton F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6335 , http://hdl.handle.net/10962/d1012399
- Description: a.k.a. Breyten Breytenbach brings together a collection of 14 essays by 12 scholars on the work of this remarkable South African writer, poet and painter. Designating Breytenbach as ‘South African’ is, of course, already a highly contentious act. It relates directly to the central concern of this volume (and one of the central concerns of Breytenbach’s work), namely the question of identity. The title characterises the artist’s proper name as but one in a series of constantly shifting and interchanging personas adopted in his art (and in his life, e.g. when working underground in the 1970s to contribute to the overthrow of the apartheid regime). The painting on the cover further explores the theme of the mask, with the white male figure’s face covered by a book-like object (although his eyes are partially visible through the object), and the presence of a burning hat floating in the air next to him serves as an additional link with many of his other paintings where headgear is associated with shifting identities, as pointed out by Marilet Sienaert in her essay, “The I of the Beholder: Identity and Place in the Art and Writing.” Like several of the other authors, Sienaert places great emphasis on the notion of movement or transformation as critical to Breytenbach’s thinking and creative practice. It is virtually unavoidable, given his background, that he should grapple with “the contemporary notion of ‘home’ being both everywhere and nowhere”, and that travel and nomadism should have become two of the most prominent themes in his poetry as well as his prose. Identity and creativity are both dependent upon the ability to constantly renew oneself and to “keep moving”.
- Full Text:
- Date Issued: 2005
- Authors: Vorster, Anton F
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6335 , http://hdl.handle.net/10962/d1012399
- Description: a.k.a. Breyten Breytenbach brings together a collection of 14 essays by 12 scholars on the work of this remarkable South African writer, poet and painter. Designating Breytenbach as ‘South African’ is, of course, already a highly contentious act. It relates directly to the central concern of this volume (and one of the central concerns of Breytenbach’s work), namely the question of identity. The title characterises the artist’s proper name as but one in a series of constantly shifting and interchanging personas adopted in his art (and in his life, e.g. when working underground in the 1970s to contribute to the overthrow of the apartheid regime). The painting on the cover further explores the theme of the mask, with the white male figure’s face covered by a book-like object (although his eyes are partially visible through the object), and the presence of a burning hat floating in the air next to him serves as an additional link with many of his other paintings where headgear is associated with shifting identities, as pointed out by Marilet Sienaert in her essay, “The I of the Beholder: Identity and Place in the Art and Writing.” Like several of the other authors, Sienaert places great emphasis on the notion of movement or transformation as critical to Breytenbach’s thinking and creative practice. It is virtually unavoidable, given his background, that he should grapple with “the contemporary notion of ‘home’ being both everywhere and nowhere”, and that travel and nomadism should have become two of the most prominent themes in his poetry as well as his prose. Identity and creativity are both dependent upon the ability to constantly renew oneself and to “keep moving”.
- Full Text:
- Date Issued: 2005
Abundance and commercialization of Phoenix Reclinata in the King Williamstown area, South Africa
- Gyan, C A, Shackleton, Charlie M
- Authors: Gyan, C A , Shackleton, Charlie M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6634 , http://hdl.handle.net/10962/d1006829
- Description: In the Eastern Cape of South Africa the fronds of the wild palm Phoenix reclinata are harvested by rural women and manufactured into hand brushes, which are sold in urban centres. This paper reports on the abundance of P. reclinata palms, the profile of the harvesters, and the economic returns from trading in palm brushes as a case study of locally driven non-timber forest product commercialization. The palm resource was in a reasonable state with most clumps being lightly (36%) or moderately (43%) harvested, with many others uncut due to physical or culturally defined refugia. Tall trees within a clump were uncut because the fronds were too high. The estimated production of fronds was less than 25 per cent of the local demand. Consequently, harvesters were seeking alternative areas and species. Mean gross monthly income was R475 (USD45) which was an important cash contribution. Net income was 75 per cent of this. Income earned per seller was influenced by factors such as age, education, hours in the trade, and whether any household member received an old-age pension from the State. Older and less educated sellers had been trading longer than younger or more educated vendors.
- Full Text:
- Date Issued: 2005
- Authors: Gyan, C A , Shackleton, Charlie M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6634 , http://hdl.handle.net/10962/d1006829
- Description: In the Eastern Cape of South Africa the fronds of the wild palm Phoenix reclinata are harvested by rural women and manufactured into hand brushes, which are sold in urban centres. This paper reports on the abundance of P. reclinata palms, the profile of the harvesters, and the economic returns from trading in palm brushes as a case study of locally driven non-timber forest product commercialization. The palm resource was in a reasonable state with most clumps being lightly (36%) or moderately (43%) harvested, with many others uncut due to physical or culturally defined refugia. Tall trees within a clump were uncut because the fronds were too high. The estimated production of fronds was less than 25 per cent of the local demand. Consequently, harvesters were seeking alternative areas and species. Mean gross monthly income was R475 (USD45) which was an important cash contribution. Net income was 75 per cent of this. Income earned per seller was influenced by factors such as age, education, hours in the trade, and whether any household member received an old-age pension from the State. Older and less educated sellers had been trading longer than younger or more educated vendors.
- Full Text:
- Date Issued: 2005
African herbal medicines in the treatment of HIV: Hypoxis and Sutherlandia: an overview of evidence and pharmacology
- Mills, Edward, Cooper, Curtis, Seely, Dugald, Kanfer, Isadore
- Authors: Mills, Edward , Cooper, Curtis , Seely, Dugald , Kanfer, Isadore
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6401 , http://hdl.handle.net/10962/d1006337
- Description: In Africa, herbal medicines are often used as primary treatment for HIV/AIDS and for HIV-related problems. In general, traditional medicines are not well researched, and are poorly regulated. We review the evidence and safety concerns related to the use of two specific African herbals, which are currently recommended by the Ministry of Health in South Africa and member states for use in HIV: African Potato and Sutherlandia. We review the pharmacology, toxicology and pharmacokinetics of these herbal medicines. Despite the popularity of their use and the support of Ministries of Health and NGOs in some African countries, no clinical trials of efficacy exist, and low-level evidence of harm identifies the potential for drug interactions with antiretroviral drugs. Efforts should be made by mainstream health professionals to provide validated information to traditional healers and patients on the judicious use of herbal remedies. This may reduce harm through failed expectations, pharmacologic adverse events including possible drug/herb interactions and unnecessary added therapeutic costs. Efforts should also be directed at evaluating the possible benefits of natural products in HIV/AIDS treatment.
- Full Text:
- Date Issued: 2005
- Authors: Mills, Edward , Cooper, Curtis , Seely, Dugald , Kanfer, Isadore
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6401 , http://hdl.handle.net/10962/d1006337
- Description: In Africa, herbal medicines are often used as primary treatment for HIV/AIDS and for HIV-related problems. In general, traditional medicines are not well researched, and are poorly regulated. We review the evidence and safety concerns related to the use of two specific African herbals, which are currently recommended by the Ministry of Health in South Africa and member states for use in HIV: African Potato and Sutherlandia. We review the pharmacology, toxicology and pharmacokinetics of these herbal medicines. Despite the popularity of their use and the support of Ministries of Health and NGOs in some African countries, no clinical trials of efficacy exist, and low-level evidence of harm identifies the potential for drug interactions with antiretroviral drugs. Efforts should be made by mainstream health professionals to provide validated information to traditional healers and patients on the judicious use of herbal remedies. This may reduce harm through failed expectations, pharmacologic adverse events including possible drug/herb interactions and unnecessary added therapeutic costs. Efforts should also be directed at evaluating the possible benefits of natural products in HIV/AIDS treatment.
- Full Text:
- Date Issued: 2005
An LC-MS-MS method for the determination of cyclizine in human serum
- Mohammadi, Ali, Kanfer, Isadore, Sewram, V, Walker, Roderick B
- Authors: Mohammadi, Ali , Kanfer, Isadore , Sewram, V , Walker, Roderick B
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6408 , http://hdl.handle.net/10962/d1006481
- Description: Cyclizine is a piperazine derivative with anti-emetic activity that is useful in the prevention and treatment of nausea and vomiting associated with motion sickness. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the quantitation of cyclizine in serum. Sample pretreatment involved liquid-liquid extraction of 200 μl of serum with dichloromethane after the addition of 100 μl each of ammonium hydroxide and internal standard solutions. The extracts were analyzed by HPLC on a Luna ® C18 reversed-phase column and an ion-trap mass spectrometer with an electrospray interface. A limit of detection of 1 ng/ml was determined which allowed for the reliable measurement of cyclizine in the serum of human subjects. The method was found to be linear over the calibration range of 2.5-100 ng/ml. The applicability of this method was demonstrated by the analysis of serum obtained from a human volunteer following administration of a single 50 mg cyclizine hydrochloride tablet. The reported method was observed to have the necessary sensitivity, selectivity, precision and accuracy for monitoring cyclizine concentrations in human subjects following oral administration.
- Full Text:
- Date Issued: 2005
- Authors: Mohammadi, Ali , Kanfer, Isadore , Sewram, V , Walker, Roderick B
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6408 , http://hdl.handle.net/10962/d1006481
- Description: Cyclizine is a piperazine derivative with anti-emetic activity that is useful in the prevention and treatment of nausea and vomiting associated with motion sickness. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the quantitation of cyclizine in serum. Sample pretreatment involved liquid-liquid extraction of 200 μl of serum with dichloromethane after the addition of 100 μl each of ammonium hydroxide and internal standard solutions. The extracts were analyzed by HPLC on a Luna ® C18 reversed-phase column and an ion-trap mass spectrometer with an electrospray interface. A limit of detection of 1 ng/ml was determined which allowed for the reliable measurement of cyclizine in the serum of human subjects. The method was found to be linear over the calibration range of 2.5-100 ng/ml. The applicability of this method was demonstrated by the analysis of serum obtained from a human volunteer following administration of a single 50 mg cyclizine hydrochloride tablet. The reported method was observed to have the necessary sensitivity, selectivity, precision and accuracy for monitoring cyclizine concentrations in human subjects following oral administration.
- Full Text:
- Date Issued: 2005
Anti-oesophageal cancer activity in extracts of deep-water Marion Island sponges
- Davies-Coleman, Michael T, Froneman, P William, Keyzers, Robert A, Whibley, Catherine, Hendricks, Denver T, Samaai, Toufiek, McQuaid, Christopher D
- Authors: Davies-Coleman, Michael T , Froneman, P William , Keyzers, Robert A , Whibley, Catherine , Hendricks, Denver T , Samaai, Toufiek , McQuaid, Christopher D
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6569 , http://hdl.handle.net/10962/d1004132
- Description: Oesophageal cancer is one of the most common causes of cancer-related deaths in South African black males. The limited efficacy of chemotherapeutic agents to treat this disease has prompted a search for potential new chemical entities with anticancer properties. We report here on the evidence for anti-oesophageal cancer activity in the methanolic extracts of five species of sponges dredged from a depth of approximately 100 m in the vicinity of Marion Island in the Southern Ocean during the autumn of 2004.
- Full Text:
- Date Issued: 2005
- Authors: Davies-Coleman, Michael T , Froneman, P William , Keyzers, Robert A , Whibley, Catherine , Hendricks, Denver T , Samaai, Toufiek , McQuaid, Christopher D
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6569 , http://hdl.handle.net/10962/d1004132
- Description: Oesophageal cancer is one of the most common causes of cancer-related deaths in South African black males. The limited efficacy of chemotherapeutic agents to treat this disease has prompted a search for potential new chemical entities with anticancer properties. We report here on the evidence for anti-oesophageal cancer activity in the methanolic extracts of five species of sponges dredged from a depth of approximately 100 m in the vicinity of Marion Island in the Southern Ocean during the autumn of 2004.
- Full Text:
- Date Issued: 2005
Art for the masses? Justification for the public support of the arts in developing countries – two arts festivals in South Africa
- Authors: Snowball, Jeanette D
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6077 , http://hdl.handle.net/10962/d1006127 , http://dx.doi.org/10.1007/s10824-005-5064-5
- Description: In the New South Africa, as in other developing countries, the equitable distribution of public resources is a priority. The case for public support of the arts is thus difficult to make because it has been shown and borne out by South African research, that arts audiences tend to represent the better educated, more prosperous minority of society, not the majority of the very poor, mainly African-origin population. Using data from willingness to pay studies conducted at two South African arts festivals, this paper shows that, when the positive externalities provided by the arts are included in their valuation, it can be shown that both high and low income earners benefit. However, as suggested by Seaman (2003), it is also found that some of what the WTP figure is capturing is current and expected future economic benefit from the event.
- Full Text:
- Date Issued: 2005
- Authors: Snowball, Jeanette D
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6077 , http://hdl.handle.net/10962/d1006127 , http://dx.doi.org/10.1007/s10824-005-5064-5
- Description: In the New South Africa, as in other developing countries, the equitable distribution of public resources is a priority. The case for public support of the arts is thus difficult to make because it has been shown and borne out by South African research, that arts audiences tend to represent the better educated, more prosperous minority of society, not the majority of the very poor, mainly African-origin population. Using data from willingness to pay studies conducted at two South African arts festivals, this paper shows that, when the positive externalities provided by the arts are included in their valuation, it can be shown that both high and low income earners benefit. However, as suggested by Seaman (2003), it is also found that some of what the WTP figure is capturing is current and expected future economic benefit from the event.
- Full Text:
- Date Issued: 2005
Attitudes of Xhosa-speaking students at the University of Fort Hare towards the use of Xhosa as a language of learning and teaching (LOLT)
- Dalvit, Lorenzo, De Klerk, Vivian A
- Authors: Dalvit, Lorenzo , De Klerk, Vivian A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6100 , http://hdl.handle.net/10962/d1008664
- Description: This article presents and discusses the results of a survey of a sample of Xhosa-speaking students at the University of Fort Hare regarding their attitudes towards the possible introduction of Xhosa as a medium of instruction at this institution. The research takes into account, among other things, the students' attitudes towards English and Xhosa and their opinions and beliefs about the introduction of dual-mediumship and its possible consequences. The survey was conducted with questionnaires and interviews and the results were first analysed as a whole, and then split into different categories according to gender, year of study, subject studied etc. This analysis indicates that while English is recognised as the dominant language in South Africa and, more specifically, in the domain of education, some categories of respondents acknowledge the usefulness of Xhosa as an additional medium of instruction. This survey clearly shows that it would make little sense to present Xhosa-speaking students at Fort Hare with a rigid choice between the existing English-medium and a dual-medium (English and Xhosa) policy and that more nuanced options would need to be offered. For example, respondents seem to consider the use of Xhosa as a medium of instruction more appropriate in the first years of study, for selected subjects and in some domains within the academic context rather than others. This study can be fruitfully compared with similar research carried out at other South African institutions. Moreover, the results of the present research can be used to inform future decisions regarding language policy at the University of Fort Hare.
- Full Text:
- Date Issued: 2005
- Authors: Dalvit, Lorenzo , De Klerk, Vivian A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6100 , http://hdl.handle.net/10962/d1008664
- Description: This article presents and discusses the results of a survey of a sample of Xhosa-speaking students at the University of Fort Hare regarding their attitudes towards the possible introduction of Xhosa as a medium of instruction at this institution. The research takes into account, among other things, the students' attitudes towards English and Xhosa and their opinions and beliefs about the introduction of dual-mediumship and its possible consequences. The survey was conducted with questionnaires and interviews and the results were first analysed as a whole, and then split into different categories according to gender, year of study, subject studied etc. This analysis indicates that while English is recognised as the dominant language in South Africa and, more specifically, in the domain of education, some categories of respondents acknowledge the usefulness of Xhosa as an additional medium of instruction. This survey clearly shows that it would make little sense to present Xhosa-speaking students at Fort Hare with a rigid choice between the existing English-medium and a dual-medium (English and Xhosa) policy and that more nuanced options would need to be offered. For example, respondents seem to consider the use of Xhosa as a medium of instruction more appropriate in the first years of study, for selected subjects and in some domains within the academic context rather than others. This study can be fruitfully compared with similar research carried out at other South African institutions. Moreover, the results of the present research can be used to inform future decisions regarding language policy at the University of Fort Hare.
- Full Text:
- Date Issued: 2005
Biological removal of nitrogen species from metal-processing wastewater
- Kasia, J M, Duncan, John R, Burgess, Jo E
- Authors: Kasia, J M , Duncan, John R , Burgess, Jo E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6482 , http://hdl.handle.net/10962/d1006256
- Description: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors' work using synthetic wastewater.
- Full Text:
- Date Issued: 2005
- Authors: Kasia, J M , Duncan, John R , Burgess, Jo E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6482 , http://hdl.handle.net/10962/d1006256
- Description: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors' work using synthetic wastewater.
- Full Text:
- Date Issued: 2005
Burrow utilization by springhares (Pedetescapensis) in the Eastern Cape, South Africa
- Authors: Peinke, D M , Brown, C R
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6962 , http://hdl.handle.net/10962/d1012025
- Description: The use of burrows by springhares was investigated in the Eastern Cape, South Africa using radio telemetry. Springhares utilized 4–27 different burrows scattered over areas ranging from 0.6–28.5 ha, with maximum distances of 170–1000 m between burrows. Springhares frequently changed burrows, seldom spending more than a few consecutive days in each, unless rearing young. The number of burrows used by individuals was correlated with the length of time they were tracked and, even after a year, some individuals were still occupying burrows previously unused by them. Males and females did not differ significantly in the mean number of burrows used, the mean area over which these were distributed, or the mean maximum distance between burrows. Springhares were generally solitary and occupied burrows were, with few exceptions, apparently avoided by conspecifics.
- Full Text:
- Date Issued: 2005
- Authors: Peinke, D M , Brown, C R
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6962 , http://hdl.handle.net/10962/d1012025
- Description: The use of burrows by springhares was investigated in the Eastern Cape, South Africa using radio telemetry. Springhares utilized 4–27 different burrows scattered over areas ranging from 0.6–28.5 ha, with maximum distances of 170–1000 m between burrows. Springhares frequently changed burrows, seldom spending more than a few consecutive days in each, unless rearing young. The number of burrows used by individuals was correlated with the length of time they were tracked and, even after a year, some individuals were still occupying burrows previously unused by them. Males and females did not differ significantly in the mean number of burrows used, the mean area over which these were distributed, or the mean maximum distance between burrows. Springhares were generally solitary and occupied burrows were, with few exceptions, apparently avoided by conspecifics.
- Full Text:
- Date Issued: 2005
Cholera in KwaZulu-Natal : probing institutional governmentality and indigenous hand-washing practices
- Authors: O’Donoghue, Rob
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6094 , http://hdl.handle.net/10962/d1008616
- Description: The paper reviews education activities in a successful anti-cholera campaign amongst rural communities in eastern southern Africa. It is centred on probing how a modern institutional governmentality was relatively blind to an historical legacy of Nguni hand-washing practices and came to exclude use of simple tests for coliform contamination in rural health education activities. The study examines institutional processes, probing discontinuities between the health education message and the complex social ecology of cholera. In so doing, it uncovers how a post-apartheid institutional rhetoric of participation, empowerment and social transformation is playing out in communicative interventions to instil healthier practices amongst the rural poor. Institutional perspectives such as this are rooted in an institutional legacy of appropriation and control. Despite the current rhetoric of participation, instrumental orientations are being sustained as the radical critique of struggle for freedom and change gives way, through comfortable submission and intellectual conformity, to an instrumental conservatism in many post-apartheid institutional settings today. The study notes and probes a surprising resonance between the ecology of the disease and an intergenerational social capital of indigenous hand-washing practices. The evidence suggests that these patterns of hand-washing practice would have served to contain the disease in earlier times and points to this social capital as a focus for co-engaged action on environment and health concerns. The findings suggest that an opposing of institutional and indigenous knowledge is not a simple matter and that moving beyond a legacy of cultural exclusion and marginalisation remains a challenge as the first decade of post-apartheid democratic governance comes to a close.
- Full Text:
- Date Issued: 2005
- Authors: O’Donoghue, Rob
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6094 , http://hdl.handle.net/10962/d1008616
- Description: The paper reviews education activities in a successful anti-cholera campaign amongst rural communities in eastern southern Africa. It is centred on probing how a modern institutional governmentality was relatively blind to an historical legacy of Nguni hand-washing practices and came to exclude use of simple tests for coliform contamination in rural health education activities. The study examines institutional processes, probing discontinuities between the health education message and the complex social ecology of cholera. In so doing, it uncovers how a post-apartheid institutional rhetoric of participation, empowerment and social transformation is playing out in communicative interventions to instil healthier practices amongst the rural poor. Institutional perspectives such as this are rooted in an institutional legacy of appropriation and control. Despite the current rhetoric of participation, instrumental orientations are being sustained as the radical critique of struggle for freedom and change gives way, through comfortable submission and intellectual conformity, to an instrumental conservatism in many post-apartheid institutional settings today. The study notes and probes a surprising resonance between the ecology of the disease and an intergenerational social capital of indigenous hand-washing practices. The evidence suggests that these patterns of hand-washing practice would have served to contain the disease in earlier times and points to this social capital as a focus for co-engaged action on environment and health concerns. The findings suggest that an opposing of institutional and indigenous knowledge is not a simple matter and that moving beyond a legacy of cultural exclusion and marginalisation remains a challenge as the first decade of post-apartheid democratic governance comes to a close.
- Full Text:
- Date Issued: 2005
Comparison of maximal aerobic capacity during running and lifting activities : research article
- Christie, Candice J, Scott, Patricia A
- Authors: Christie, Candice J , Scott, Patricia A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6745 , http://hdl.handle.net/10962/d1009314
- Description: Acknowledging the specificity of assessing maximal output, the purpose of this paper was to compare the physiological and perceptual responses during a traditional running activity and the common industrial task of lifting; both were taken to maximal effort. The responses of eight male participants were measured during both physical activities separated by at least five days: i) a progressive speed protocol (PSP) involved running on a treadmill at increasing speeds, starting at 10 km.h[superscript -1] and increasing by 1 km.h[superscript -1] every minute until exhaustion; ii) a progressive frequency protocol (PFP) required participants to lift a load of 20% body mass at increasing lifting frequencies, starting at one lift every 10s and reducing the time between lifts by 1s every minute until exhaustion. Physiological responses were measured using a portable on-line system, the K4b[superscript 2] (Cosmed(r)). "Central" perceptual measures were obtained every minute using the rating of perceived exertion (RPE) scale. Results: Responses increased progressively with augmented exercise intensity in both protocols; however, oxygen consumption and peak oxygen values were both lower during the lifting protocol compared to the running protocol. In contrast to the oxygen uptake responses, peak RER values were significantly higher during lifting (mean of 1.32) than running (mean of 1.18), while maximal heart rate and perceptual responses revealed no significant difference between the two protocols. These findings caution against using the 'traditional' treadmill protocol to assess the aerobic capacity of manual labourers involved in lifting, as it is evident that the traditional lower body protocol will indicate a higher capacity than the maximum capacity of an upper body activity, which could lead to manual labourers being taxed beyond acceptable limits.
- Full Text:
- Date Issued: 2005
- Authors: Christie, Candice J , Scott, Patricia A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6745 , http://hdl.handle.net/10962/d1009314
- Description: Acknowledging the specificity of assessing maximal output, the purpose of this paper was to compare the physiological and perceptual responses during a traditional running activity and the common industrial task of lifting; both were taken to maximal effort. The responses of eight male participants were measured during both physical activities separated by at least five days: i) a progressive speed protocol (PSP) involved running on a treadmill at increasing speeds, starting at 10 km.h[superscript -1] and increasing by 1 km.h[superscript -1] every minute until exhaustion; ii) a progressive frequency protocol (PFP) required participants to lift a load of 20% body mass at increasing lifting frequencies, starting at one lift every 10s and reducing the time between lifts by 1s every minute until exhaustion. Physiological responses were measured using a portable on-line system, the K4b[superscript 2] (Cosmed(r)). "Central" perceptual measures were obtained every minute using the rating of perceived exertion (RPE) scale. Results: Responses increased progressively with augmented exercise intensity in both protocols; however, oxygen consumption and peak oxygen values were both lower during the lifting protocol compared to the running protocol. In contrast to the oxygen uptake responses, peak RER values were significantly higher during lifting (mean of 1.32) than running (mean of 1.18), while maximal heart rate and perceptual responses revealed no significant difference between the two protocols. These findings caution against using the 'traditional' treadmill protocol to assess the aerobic capacity of manual labourers involved in lifting, as it is evident that the traditional lower body protocol will indicate a higher capacity than the maximum capacity of an upper body activity, which could lead to manual labourers being taxed beyond acceptable limits.
- Full Text:
- Date Issued: 2005
Contrasting spatial heterogeneity of sessile organisms within mussel (Perna perna L.) beds in relation to topographic variability
- Erlandsson, J, McQuaid, Christopher D, Kostylev, V E
- Authors: Erlandsson, J , McQuaid, Christopher D , Kostylev, V E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6949 , http://hdl.handle.net/10962/d1011979
- Description: We examined the spatial heterogeneity in three sessile rocky shore organisms, the mussel Perna perna, the barnacle Octomeris angulosa (Sowerby) and the red alga Gelidium pristoides (Turn.) at a range of continuous local scales along horizontal transects within mid- and upper mussel beds of South African shores. We also examined the relationships between variability of organisms and topographic features (rock depressions, slope, aspect), and between mussel, barnacle and algal variability over the same scales. To estimate spatial heterogeneity, we analyzed scaling properties of semivariograms using a fractal approach. Relationships between different variables at the different scales were examined by cross-semivariograms. Spatial dependence of P. perna variability increased with spatial dependence of topographic variability, so that scaling regions of mussel and topographic distributions corresponded well. This relationship often improved with larger local scales (mussel cover increased with depressions, steeper slope and aspect towards waves), while at smaller spatial scales, variability in mussel cover was less well explained by variability in topography. The variability of the barnacle O. angulosa exhibited spatial dependence, even on topographically unstructured shores. In contrast, the distribution of the alga G. pristoides revealed high fractal dimensions, showing spatial independence on topographically unstructured shores. Algae also showed a very strong negative relationship with mussels at most local scales, and a negative relationship with barnacles in upper zones, especially at larger local scales. Barnacles may show clear spatial dependence because of hydrodynamics (at larger local scales) and the need to find a future mate in close proximity (at smaller local scales), while algae may show a strong negative relationship with mussels because of competition for space.
- Full Text:
- Date Issued: 2005
- Authors: Erlandsson, J , McQuaid, Christopher D , Kostylev, V E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6949 , http://hdl.handle.net/10962/d1011979
- Description: We examined the spatial heterogeneity in three sessile rocky shore organisms, the mussel Perna perna, the barnacle Octomeris angulosa (Sowerby) and the red alga Gelidium pristoides (Turn.) at a range of continuous local scales along horizontal transects within mid- and upper mussel beds of South African shores. We also examined the relationships between variability of organisms and topographic features (rock depressions, slope, aspect), and between mussel, barnacle and algal variability over the same scales. To estimate spatial heterogeneity, we analyzed scaling properties of semivariograms using a fractal approach. Relationships between different variables at the different scales were examined by cross-semivariograms. Spatial dependence of P. perna variability increased with spatial dependence of topographic variability, so that scaling regions of mussel and topographic distributions corresponded well. This relationship often improved with larger local scales (mussel cover increased with depressions, steeper slope and aspect towards waves), while at smaller spatial scales, variability in mussel cover was less well explained by variability in topography. The variability of the barnacle O. angulosa exhibited spatial dependence, even on topographically unstructured shores. In contrast, the distribution of the alga G. pristoides revealed high fractal dimensions, showing spatial independence on topographically unstructured shores. Algae also showed a very strong negative relationship with mussels at most local scales, and a negative relationship with barnacles in upper zones, especially at larger local scales. Barnacles may show clear spatial dependence because of hydrodynamics (at larger local scales) and the need to find a future mate in close proximity (at smaller local scales), while algae may show a strong negative relationship with mussels because of competition for space.
- Full Text:
- Date Issued: 2005
Critical perspectives on research on post-traumatic stress disorder and implications for the South African context
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6228 , http://hdl.handle.net/10962/d1007778
- Description: This article introduces a special issue of the Journal of Psychology in Africa on post-traumatic stress disorder (PTSD) in Africa and particularly in South Africa and examines the critical debate that has surrounded PTSD research. It begins with an examination of the meaning of the term trauma, and of its specialised use within the clinical context and with respect to the concept of PTSD. The diagnostic approach to the detection of PTSD is presented, criteria in the DSM-IV-TR and the ICD-10 are summarised and differences between the two manuals are discussed. Arguments presented by critics of the concept of PTSD are presented and discussed. These concern the historical evolution of the concept, concerns about the universality of PTSD cross-culturally, and problems arising from understanding human suffering from a narrow medical perspective. It is concluded that while there are dangers in thinking of the sequelae of trauma as a medical/psychiatric problem, and while the alarming rate of traumatic events needs to be addressed at the political, economic and societal level, there is an important place for the provision of assessment and treatment of PTSD within a psychiatric/psychological clinical setting.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6228 , http://hdl.handle.net/10962/d1007778
- Description: This article introduces a special issue of the Journal of Psychology in Africa on post-traumatic stress disorder (PTSD) in Africa and particularly in South Africa and examines the critical debate that has surrounded PTSD research. It begins with an examination of the meaning of the term trauma, and of its specialised use within the clinical context and with respect to the concept of PTSD. The diagnostic approach to the detection of PTSD is presented, criteria in the DSM-IV-TR and the ICD-10 are summarised and differences between the two manuals are discussed. Arguments presented by critics of the concept of PTSD are presented and discussed. These concern the historical evolution of the concept, concerns about the universality of PTSD cross-culturally, and problems arising from understanding human suffering from a narrow medical perspective. It is concluded that while there are dangers in thinking of the sequelae of trauma as a medical/psychiatric problem, and while the alarming rate of traumatic events needs to be addressed at the political, economic and societal level, there is an important place for the provision of assessment and treatment of PTSD within a psychiatric/psychological clinical setting.
- Full Text:
- Date Issued: 2005
Current trends in research focused on pushing and pulling : research article
- Authors: Todd, Andrew I
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6744 , http://hdl.handle.net/10962/d1009313
- Description: The purpose of this review paper is to provide a synopsis of the findings of papers on pushing and pulling; and to identify areas of contention which require further in depth analysis. It is evident from reviewing the published papers on pushing and pulling that there is a lack of consensus as to which one of these two actions has the greatest force production. The main problem is probably the lack of standardized methodology in push-pull research. Furthermore, even when similar methodologies have been used the description of postures adopted during testing by the subjects varies greatly from paper to paper. The various studies have employed different postures and also imposed different restrictions on the postures adopted during experimentation, making comparisons between findings difficult. Much emphasis has been placed on the evaluation of static pushing and pulling tasks, and there is a clear need for further research into dynamic pushing and pulling. Additionally to date the focus of much of this research has been on the biomechanical stresses placed on the body with little attention being given to the physiological cost of pushing and pulling.
- Full Text:
- Date Issued: 2005
- Authors: Todd, Andrew I
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6744 , http://hdl.handle.net/10962/d1009313
- Description: The purpose of this review paper is to provide a synopsis of the findings of papers on pushing and pulling; and to identify areas of contention which require further in depth analysis. It is evident from reviewing the published papers on pushing and pulling that there is a lack of consensus as to which one of these two actions has the greatest force production. The main problem is probably the lack of standardized methodology in push-pull research. Furthermore, even when similar methodologies have been used the description of postures adopted during testing by the subjects varies greatly from paper to paper. The various studies have employed different postures and also imposed different restrictions on the postures adopted during experimentation, making comparisons between findings difficult. Much emphasis has been placed on the evaluation of static pushing and pulling tasks, and there is a clear need for further research into dynamic pushing and pulling. Additionally to date the focus of much of this research has been on the biomechanical stresses placed on the body with little attention being given to the physiological cost of pushing and pulling.
- Full Text:
- Date Issued: 2005
Derivation of quantitative management objectives for annual instream water temperatures in the Sabie River using a biological index
- Rivers-Moore, Nick A, Jewitt, G P W, Weeks, D C
- Authors: Rivers-Moore, Nick A , Jewitt, G P W , Weeks, D C
- Date: 2005
- Language: English
- Type: text , Article
- Identifier: vital:7093 , http://hdl.handle.net/10962/d1012426
- Description: Adaptive management of river systems assumes uncertainty and makes provision for system variability. Inherent within this management approach is that perceived limits of 'acceptable' system variability are regarded not only as testable hypotheses, but also as playing a central role in maintaining biodiversity. While the Kruger National Park currently functions as a flagship conservation area in South Africa, projected increases in air temperatures as a consequence of global climate change present challenges in conserving this biodiversity inside the established land boundaries. Within the rivers of the Kruger National Park, a management goal of maintaining biodiversity requires a clearer understanding of system variability. One component of this is water temperature, an important water quality parameter defining the distribution patterns of aquatic organisms. In this study, Chiloglanis anoterus Crass (1960) (Pisces: Mochokidae) was selected as a biological indicator of changes in annual water temperatures within the Sabie River in the southern Kruger National Park. Relative abundances of C. anoterus were determined using standard electro-fishing surveys. The presence or absence of C. anoterus was linked to cumulative annual heat units using a logistic regression model, and a critical annual cumulative water temperature threshold estimated. A correlative relationship between this temperature threshold and a biological index using a C. anoterus condition factor provides river ecologists with a tool to assess ecologically significant warming trends in Sabie River water temperatures. A similar approach could be applied with relative ease to other Southern African river systems. Further testing of this hypothesis is suggested, as part of the adaptive management cycle.
- Full Text:
- Date Issued: 2005
- Authors: Rivers-Moore, Nick A , Jewitt, G P W , Weeks, D C
- Date: 2005
- Language: English
- Type: text , Article
- Identifier: vital:7093 , http://hdl.handle.net/10962/d1012426
- Description: Adaptive management of river systems assumes uncertainty and makes provision for system variability. Inherent within this management approach is that perceived limits of 'acceptable' system variability are regarded not only as testable hypotheses, but also as playing a central role in maintaining biodiversity. While the Kruger National Park currently functions as a flagship conservation area in South Africa, projected increases in air temperatures as a consequence of global climate change present challenges in conserving this biodiversity inside the established land boundaries. Within the rivers of the Kruger National Park, a management goal of maintaining biodiversity requires a clearer understanding of system variability. One component of this is water temperature, an important water quality parameter defining the distribution patterns of aquatic organisms. In this study, Chiloglanis anoterus Crass (1960) (Pisces: Mochokidae) was selected as a biological indicator of changes in annual water temperatures within the Sabie River in the southern Kruger National Park. Relative abundances of C. anoterus were determined using standard electro-fishing surveys. The presence or absence of C. anoterus was linked to cumulative annual heat units using a logistic regression model, and a critical annual cumulative water temperature threshold estimated. A correlative relationship between this temperature threshold and a biological index using a C. anoterus condition factor provides river ecologists with a tool to assess ecologically significant warming trends in Sabie River water temperatures. A similar approach could be applied with relative ease to other Southern African river systems. Further testing of this hypothesis is suggested, as part of the adaptive management cycle.
- Full Text:
- Date Issued: 2005