Pollination success in a deceptive orchid is enhanced by co-occurring rewarding magnet plants
- Johnson, Steven D, Peter, Craig I, Nilsson, L Anders, Agren, Jon
- Authors: Johnson, Steven D , Peter, Craig I , Nilsson, L Anders , Agren, Jon
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6520 , http://hdl.handle.net/10962/d1005949 , http://www.jstor.org/stable/3449962
- Description: It has been debated whether pollination success in nonrewarding plants that flower in association with nectar-producing plants will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the nonrewarding bumblebee-pollinated orchid Anacamptis morio and associated nectar-producing plants at a site in Sweden. Pollination success (estimated as pollen receipt and pollen removal) in A. morio was significantly greater for individuals translocated to patches of nectar-producing plants (Geum rivale and Allium schoenoprasum) than for individuals placed outside (similar to20 m away) such patches. These results provide support for the existence of a facilitative magnet species effect in the interaction between certain nectar plants and A. morio. To determine the spatial scale of these interactions, we correlated the visitation rate to flowers of A. morio with the density of sympatric nectar plants in 1-m(2) and 100-m(2) plots centered around groups of translocated plants, and at the level of whole meadows (similar to0.5-2 ha). Visitation rate to flowers of A. morio was not correlated with the 1-m(2) patch density of G. rivale and A. schoenoprasum, but showed a significant positive relationship with density of these nectar plants in 100-m(2) plots. In addition, visitation to flowers of A. morio was strongly and positively related to the density of A. schoenoprasum at the level of the meadow. Choice experiments showed that bees foraging on the purple flowers of A. schoenoprasum (a particularly effective magnet species) visit the purple flowers of A. morio more readily (47.6% of choices) than bees foraging on the yellow flowers of Lotus corniculatus (17% of choices). Overall similarity in flower color and shape may increase the probability that a pollinator will temporarily shift from a nectar-producing "magnet" plant to a nonrewarding plant. We discuss the possibility of a mimicry continuum between those orchids that exploit instinctive food-seeking behavior of pollinators and those that show an adaptive resemblance to nectar-producing plants.
- Full Text:
- Date Issued: 2003
- Authors: Johnson, Steven D , Peter, Craig I , Nilsson, L Anders , Agren, Jon
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6520 , http://hdl.handle.net/10962/d1005949 , http://www.jstor.org/stable/3449962
- Description: It has been debated whether pollination success in nonrewarding plants that flower in association with nectar-producing plants will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the nonrewarding bumblebee-pollinated orchid Anacamptis morio and associated nectar-producing plants at a site in Sweden. Pollination success (estimated as pollen receipt and pollen removal) in A. morio was significantly greater for individuals translocated to patches of nectar-producing plants (Geum rivale and Allium schoenoprasum) than for individuals placed outside (similar to20 m away) such patches. These results provide support for the existence of a facilitative magnet species effect in the interaction between certain nectar plants and A. morio. To determine the spatial scale of these interactions, we correlated the visitation rate to flowers of A. morio with the density of sympatric nectar plants in 1-m(2) and 100-m(2) plots centered around groups of translocated plants, and at the level of whole meadows (similar to0.5-2 ha). Visitation rate to flowers of A. morio was not correlated with the 1-m(2) patch density of G. rivale and A. schoenoprasum, but showed a significant positive relationship with density of these nectar plants in 100-m(2) plots. In addition, visitation to flowers of A. morio was strongly and positively related to the density of A. schoenoprasum at the level of the meadow. Choice experiments showed that bees foraging on the purple flowers of A. schoenoprasum (a particularly effective magnet species) visit the purple flowers of A. morio more readily (47.6% of choices) than bees foraging on the yellow flowers of Lotus corniculatus (17% of choices). Overall similarity in flower color and shape may increase the probability that a pollinator will temporarily shift from a nectar-producing "magnet" plant to a nonrewarding plant. We discuss the possibility of a mimicry continuum between those orchids that exploit instinctive food-seeking behavior of pollinators and those that show an adaptive resemblance to nectar-producing plants.
- Full Text:
- Date Issued: 2003
Population biology of Octopus vulgaris on the temperate south-eastern coast of South Africa
- Oosthuizen, A, Smale, Malcolm J
- Authors: Oosthuizen, A , Smale, Malcolm J
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6768 , http://hdl.handle.net/10962/d1008045
- Description: Population structure and biology of Octopus vulgaris was investigated along the south-eastern coast of South Africa. Samples were collected inter- and sub-tidally as a precursor to the establishment of an experimental octopus fishery in the region. In total, 300 (intertidal) and 147 (subtidal) O. vulgaris were collected over a two year period. Females were found to dominate the intertidal area (sex ratio 2:1), while no difference was found subtidally (sex ratio 1:1). Of those collected intertidally, immature females were most prevalent while males ranged from immature to mature. Mature females were only found subtidally. A marked size difference was apparent, with the subtidal octopus being substantially larger. Although brooding females were found throughout the year, numbers peaked in summer. Individual fecundity ranged between 42,000–790,000 eggs. The total number of eggs produced and the number of eggs per egg string were correlated to female size. Diet did not vary greatly between the inter- and sub-tidal areas, with the main prey items being crustaceans, teleosts and octopus. It appears that the immature females use the intertidal area to feed and grow, before migrating to deeper areas to mature and spawn.
- Full Text:
- Date Issued: 2003
- Authors: Oosthuizen, A , Smale, Malcolm J
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6768 , http://hdl.handle.net/10962/d1008045
- Description: Population structure and biology of Octopus vulgaris was investigated along the south-eastern coast of South Africa. Samples were collected inter- and sub-tidally as a precursor to the establishment of an experimental octopus fishery in the region. In total, 300 (intertidal) and 147 (subtidal) O. vulgaris were collected over a two year period. Females were found to dominate the intertidal area (sex ratio 2:1), while no difference was found subtidally (sex ratio 1:1). Of those collected intertidally, immature females were most prevalent while males ranged from immature to mature. Mature females were only found subtidally. A marked size difference was apparent, with the subtidal octopus being substantially larger. Although brooding females were found throughout the year, numbers peaked in summer. Individual fecundity ranged between 42,000–790,000 eggs. The total number of eggs produced and the number of eggs per egg string were correlated to female size. Diet did not vary greatly between the inter- and sub-tidal areas, with the main prey items being crustaceans, teleosts and octopus. It appears that the immature females use the intertidal area to feed and grow, before migrating to deeper areas to mature and spawn.
- Full Text:
- Date Issued: 2003
Potter's fingerprints: some prehistoric southern African utilityware in an intimate light.
- Authors: Steele, John
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/945 , vital:30070
- Description: Extensive archaeological excavations in southern Africa during the past century have revealed a richly described heritage of widely distributed First-Millennium (C.E.) Agriculturist ceramics. In viewing both artefacts and assessments thereof it can be observed that ways of thinking shape ways of seeing, and explanations ofwhat is seen. Thus, because conceptual frameworks are inseparable from what is observed and explanations that result, consideration is given to some particular mindsets that have led to recent theories concenring local prehistoric material culture. In conclusion, a brief look at dialogues initiated by some contemporary potters who interrogate cherished lifeways and belief systems serve to elucidate current trends towards finding meaning in prehistoric southern African ceramics.
- Full Text:
- Date Issued: 2003
- Authors: Steele, John
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/945 , vital:30070
- Description: Extensive archaeological excavations in southern Africa during the past century have revealed a richly described heritage of widely distributed First-Millennium (C.E.) Agriculturist ceramics. In viewing both artefacts and assessments thereof it can be observed that ways of thinking shape ways of seeing, and explanations ofwhat is seen. Thus, because conceptual frameworks are inseparable from what is observed and explanations that result, consideration is given to some particular mindsets that have led to recent theories concenring local prehistoric material culture. In conclusion, a brief look at dialogues initiated by some contemporary potters who interrogate cherished lifeways and belief systems serve to elucidate current trends towards finding meaning in prehistoric southern African ceramics.
- Full Text:
- Date Issued: 2003
Psycho-medical discourse in South African research on teenage pregnancy
- Macleod, Catriona I, Durrheim, Kevin
- Authors: Macleod, Catriona I , Durrheim, Kevin
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6257 , http://hdl.handle.net/10962/d1007875
- Description: Catriona Macleod and Kevin Durrheim apply a Foucauldian analysis to the scientific literature on teenage pregnancy.
- Full Text:
- Date Issued: 2003
- Authors: Macleod, Catriona I , Durrheim, Kevin
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6257 , http://hdl.handle.net/10962/d1007875
- Description: Catriona Macleod and Kevin Durrheim apply a Foucauldian analysis to the scientific literature on teenage pregnancy.
- Full Text:
- Date Issued: 2003
Quality of life and positive youth development in Grahamstown East, South Africa
- Authors: Moller, Valerie
- Date: 2003
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10962/2363 , vital:20281
- Description: Quality-of-life studies are ideally suited to fulfilling the new international youth research agenda, which focuses on ‘positive youth development’ to make recommendations for policy and practice. The paper reports a South African case study conducted among disadvantaged youth for this purpose. A sample survey of close on 900 African youth, aged 15-24 years, sought to identify indicators of positive development to serve as goals of youth and community work in Grahamstown East/Rini, in the Eastern Cape province of South Africa. The setting is unique. This mainly rural province is among the poorest, least developed, and has one of highest unemployment rates. Nevertheless, Grahamstown may offer special development opportunities for local youth due to the proximity of the city centre and diverse extension projects for youth. The survey found that development opportunities were unequally distributed with the materially advantaged youth being more exposed to development opportunities through their schools, spare time activities, and community contacts. They were more ambitious than others and more aware of risks facing contemporary youth. Advantaged youth also reported higher levels of subjective well-being and optimism, findings consistent with earlier studies conducted among adult populations, which report remarkable congruence between material and subjective well-being among South Africans. The analysis used overall life satisfaction as key indicator of successful youth development to learn more about major youth aspirations and goals. In conclusion, the study was able to identify a youth development initiative based on the aspirations of the youth, which might be pursued as a researcher-practitioner partnership project in line with the new international youth research agenda.
- Full Text:
- Date Issued: 2003
- Authors: Moller, Valerie
- Date: 2003
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10962/2363 , vital:20281
- Description: Quality-of-life studies are ideally suited to fulfilling the new international youth research agenda, which focuses on ‘positive youth development’ to make recommendations for policy and practice. The paper reports a South African case study conducted among disadvantaged youth for this purpose. A sample survey of close on 900 African youth, aged 15-24 years, sought to identify indicators of positive development to serve as goals of youth and community work in Grahamstown East/Rini, in the Eastern Cape province of South Africa. The setting is unique. This mainly rural province is among the poorest, least developed, and has one of highest unemployment rates. Nevertheless, Grahamstown may offer special development opportunities for local youth due to the proximity of the city centre and diverse extension projects for youth. The survey found that development opportunities were unequally distributed with the materially advantaged youth being more exposed to development opportunities through their schools, spare time activities, and community contacts. They were more ambitious than others and more aware of risks facing contemporary youth. Advantaged youth also reported higher levels of subjective well-being and optimism, findings consistent with earlier studies conducted among adult populations, which report remarkable congruence between material and subjective well-being among South Africans. The analysis used overall life satisfaction as key indicator of successful youth development to learn more about major youth aspirations and goals. In conclusion, the study was able to identify a youth development initiative based on the aspirations of the youth, which might be pursued as a researcher-practitioner partnership project in line with the new international youth research agenda.
- Full Text:
- Date Issued: 2003
Review of South African research on volcanic and related rocks and mantle-derived materials : 1999-2002
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6737 , http://hdl.handle.net/10962/d1007550
- Description: This report reviews South African research relating to the scientific interests of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and which was published between 1999 and 2002. The focus is on published work and does not include conference presentations and abstract volumes or other informal documents.
- Full Text:
- Date Issued: 2003
Review of the Cardinalfishes (Perciformes: Apogonidae) of the Red Sea
- Authors: Gon, Ofer , Randall, John E
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7150 , http://hdl.handle.net/10962/d1011853
- Description: Twelve genera and 54 species of cardinalfishes are reported from the Red Sea. The Red Sea cardinalfishes include: Apogon annularis Rüppell, A. apogonides (Bleeker), Apogon bryx Fraser, A. campbelli Smith, A. coccineus Rüppell, A. cookii Macleay, A. cyanosoma Bleeker, A. erythrosoma n. sp., A. exostigma (Jordan & Starks), A. fleurieu (Lacepède), A. fraenatus Valenciennes, A. guamensis Valenciennes, A. gularis Fraser & Lachner, A. heptastygma Cuvier, A. isus Randall & Böhlke, A. kallopterus Bleeker, A. leptacanthus Bleeker, A. multitaeniatus Cuvier, A. nigrofasciatus Lachner, A. pharaonis Bellotti, A. pselion Randall, Fraser & Lachner, A. pseudotaeniatus Gon, A. quadrifasciatus Cuvier, A. queketti Gilchrist, A. semiornatus Peters, A. smithi (Kotthaus), A. spilurus Regan, A. taeniatus Cuvier, A. talboti Smith, A. timorensis Bleeker, A. zebrinus Fraser, Randall & Lachner, Apogonichthys perdix Bleeker, Archamia bilineata Gon & Randall, Archamia fucata (Cantor), Archamia lineolata (Cuvier), Cercamia eremia (Allen), Cheilodipterus lachneri Klausewitz, C. lineatus (Forsskål), C. macrodon LacepPde, C. novemstriatus (Rüppell), C. pygmaios Gon, C. quinquelineatus Cuvier, Foa fo Jordan & Seale, Fowleria aurita (Valenciennes), F. marmorata (Alleyne & Macleay), F. vaiulae (Jordan & Seale), F. variegata (Valenciennes), Neamia octospina Smith & Radcliffe, Pseudamia gelatinosa Smith, Rhabdamia cypselura Weber, R. nigrimentum (Smith), R. spilota Allen & Kuiter, Siphamia permutata Klausewitz, and Sphaeramia orbicularis (Cuvier). Twelve (22%) of the apogonid species are endemic. Seven species, i.e. Apogon apogonides, A. campbelli, A. erythrosoma, A. talboti, Foa fo, Rhabdamia spilota and Sphaeramia orbicularis, are new to the Red Sea. Apogon coccineus of previous authors is a complex of three species, including campbelli Smith and erythrosoma n. sp. The dark-striped species of Apogon of the Red Sea previously identified as angustatus, endekataenia, fasciatus, or novemfasciatus are cookii and nigrofasciatus. Red Sea apogonids identified by previous authors as Apogon bandanensis, monochrous, nubilus and savayensis, are guamensis and zebrinus. Apogon micromaculatus Kotthaus is A. spilurus Regan. The specimen of Apogon kiensis reported by Smith (1961) from the Red Sea is A. bryx, recently described from the Philippines. In the genus Fowleria, polystigma (Bleeker) and punctulata (Rüppell) are junior synonyms of variegata (Valenciennes). F. abocellata Goren & Karplus is a junior synonym of vaiulae (Jordan & Seale), and isostigma (Jordan & Seale) does not occur in the Red Sea. Apogon cupreus and A. latus, both of Cuvier, are unidentifiable. A. hyalosoma and A. taeniophorus are doubtful records.
- Full Text:
- Date Issued: 2003
- Authors: Gon, Ofer , Randall, John E
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7150 , http://hdl.handle.net/10962/d1011853
- Description: Twelve genera and 54 species of cardinalfishes are reported from the Red Sea. The Red Sea cardinalfishes include: Apogon annularis Rüppell, A. apogonides (Bleeker), Apogon bryx Fraser, A. campbelli Smith, A. coccineus Rüppell, A. cookii Macleay, A. cyanosoma Bleeker, A. erythrosoma n. sp., A. exostigma (Jordan & Starks), A. fleurieu (Lacepède), A. fraenatus Valenciennes, A. guamensis Valenciennes, A. gularis Fraser & Lachner, A. heptastygma Cuvier, A. isus Randall & Böhlke, A. kallopterus Bleeker, A. leptacanthus Bleeker, A. multitaeniatus Cuvier, A. nigrofasciatus Lachner, A. pharaonis Bellotti, A. pselion Randall, Fraser & Lachner, A. pseudotaeniatus Gon, A. quadrifasciatus Cuvier, A. queketti Gilchrist, A. semiornatus Peters, A. smithi (Kotthaus), A. spilurus Regan, A. taeniatus Cuvier, A. talboti Smith, A. timorensis Bleeker, A. zebrinus Fraser, Randall & Lachner, Apogonichthys perdix Bleeker, Archamia bilineata Gon & Randall, Archamia fucata (Cantor), Archamia lineolata (Cuvier), Cercamia eremia (Allen), Cheilodipterus lachneri Klausewitz, C. lineatus (Forsskål), C. macrodon LacepPde, C. novemstriatus (Rüppell), C. pygmaios Gon, C. quinquelineatus Cuvier, Foa fo Jordan & Seale, Fowleria aurita (Valenciennes), F. marmorata (Alleyne & Macleay), F. vaiulae (Jordan & Seale), F. variegata (Valenciennes), Neamia octospina Smith & Radcliffe, Pseudamia gelatinosa Smith, Rhabdamia cypselura Weber, R. nigrimentum (Smith), R. spilota Allen & Kuiter, Siphamia permutata Klausewitz, and Sphaeramia orbicularis (Cuvier). Twelve (22%) of the apogonid species are endemic. Seven species, i.e. Apogon apogonides, A. campbelli, A. erythrosoma, A. talboti, Foa fo, Rhabdamia spilota and Sphaeramia orbicularis, are new to the Red Sea. Apogon coccineus of previous authors is a complex of three species, including campbelli Smith and erythrosoma n. sp. The dark-striped species of Apogon of the Red Sea previously identified as angustatus, endekataenia, fasciatus, or novemfasciatus are cookii and nigrofasciatus. Red Sea apogonids identified by previous authors as Apogon bandanensis, monochrous, nubilus and savayensis, are guamensis and zebrinus. Apogon micromaculatus Kotthaus is A. spilurus Regan. The specimen of Apogon kiensis reported by Smith (1961) from the Red Sea is A. bryx, recently described from the Philippines. In the genus Fowleria, polystigma (Bleeker) and punctulata (Rüppell) are junior synonyms of variegata (Valenciennes). F. abocellata Goren & Karplus is a junior synonym of vaiulae (Jordan & Seale), and isostigma (Jordan & Seale) does not occur in the Red Sea. Apogon cupreus and A. latus, both of Cuvier, are unidentifiable. A. hyalosoma and A. taeniophorus are doubtful records.
- Full Text:
- Date Issued: 2003
Seasonal phenology of the diamondback moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae), and its parasitoids on canola, Brassica napus (L.), in Gauteng province, South Africa
- Mosiane, S M, Kfir, R, Villet, Martin H
- Authors: Mosiane, S M , Kfir, R , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6856 , http://hdl.handle.net/10962/d1011139
- Description: Canola, Brassica napus L. (Brassicaceae), is a relativelynewcrop in SouthAfrica. Several insect pests, including diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), that attack cruciferous vegetables, also attack canola. The aims of this study were to determine the seasonal phenology of P. xylostella populations on canola, and the composition, relative abundance and seasonal phenology of parasitoids attacking P. xylostella on this crop. Diamondback moth adults were monitored with synthetic sex-pheromone traps. Larval and pupal populations of P. xylostella were monitored weekly for three years at Bapsfontein and Rietondale in Gauteng province. Samples of diamondback moth larvae, pupae and parasitoid cocoons were collected and transported to the laboratory. Parasitoids that emerged were identified and their incidence recorded. Berlese funnel catches were used as an indicator of the accuracy of the visual counts. The infestation level of P. xylostella larvae was high from May to August at Rietondale, while at Bapsfontein it was high from September to December. There was a high correlation (r=0.79, P<0.001) between pheromone trap catches and subsequent larval infestations at Bapsfontein. The pheromone traps indicated that diamondback moth adults were present throughout the year. Berlese funnel catches indicated that a large number of larvae, especially first instars, were overlooked during visual plant scouting. Parasitism rates were often very high, reaching 90–100 %. The following parasitoids were recorded from field-collected P. xylostella: the larval parasitoids Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) and Apanteles halfordi Ullyett (Hymenoptera: Braconidae), the larval/pupal parasitoids Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), the pupal parasitoid Diadromus collaris (Gravenhorst) (Hymenoptera: Ichneumonidae), and the hyperparasitoids Mesochorus sp. (Hymenoptera: Ichneumonidae) and Pteromalus sp. (Hymenoptera: Pteromalidae). Cotesia plutellae was the most abundant parasitoid throughout the study.
- Full Text:
- Date Issued: 2003
- Authors: Mosiane, S M , Kfir, R , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6856 , http://hdl.handle.net/10962/d1011139
- Description: Canola, Brassica napus L. (Brassicaceae), is a relativelynewcrop in SouthAfrica. Several insect pests, including diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), that attack cruciferous vegetables, also attack canola. The aims of this study were to determine the seasonal phenology of P. xylostella populations on canola, and the composition, relative abundance and seasonal phenology of parasitoids attacking P. xylostella on this crop. Diamondback moth adults were monitored with synthetic sex-pheromone traps. Larval and pupal populations of P. xylostella were monitored weekly for three years at Bapsfontein and Rietondale in Gauteng province. Samples of diamondback moth larvae, pupae and parasitoid cocoons were collected and transported to the laboratory. Parasitoids that emerged were identified and their incidence recorded. Berlese funnel catches were used as an indicator of the accuracy of the visual counts. The infestation level of P. xylostella larvae was high from May to August at Rietondale, while at Bapsfontein it was high from September to December. There was a high correlation (r=0.79, P<0.001) between pheromone trap catches and subsequent larval infestations at Bapsfontein. The pheromone traps indicated that diamondback moth adults were present throughout the year. Berlese funnel catches indicated that a large number of larvae, especially first instars, were overlooked during visual plant scouting. Parasitism rates were often very high, reaching 90–100 %. The following parasitoids were recorded from field-collected P. xylostella: the larval parasitoids Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) and Apanteles halfordi Ullyett (Hymenoptera: Braconidae), the larval/pupal parasitoids Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), the pupal parasitoid Diadromus collaris (Gravenhorst) (Hymenoptera: Ichneumonidae), and the hyperparasitoids Mesochorus sp. (Hymenoptera: Ichneumonidae) and Pteromalus sp. (Hymenoptera: Pteromalidae). Cotesia plutellae was the most abundant parasitoid throughout the study.
- Full Text:
- Date Issued: 2003
Solvent effects on the photochemical and fluorescence properties of zinc phthalocyanine derivatives
- Ogunsipe, Abimbola Olukayode, Maree, D, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola Olukayode , Maree, D , Nyokong, Tebello
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6586 , http://hdl.handle.net/10962/d1004162 , http://dx.doi.org/10.1016/S0022-2860(03)00155-8
- Description: The effects of solvents on the singlet oxygen, photobleaching and fluorescence quantum yields for zinc phthalocyanine (ZnPc) and its derivatives; (pyridino)zinc phthalocyanine ((py)ZnPc), zinc octaphenoxyphthalocyanine (ZnOPPc) and zinc octaestronephthalocyanine (ZnOEPc), is presented. The effects of the solvents on the ground state spectra are also discussed. The largest red shift of the Q band was observed in aromatic solvents, the highest shift being observed for 1-chloronaphthalene. Higher singlet fluorescence quantum yields were observed in THF for ZnPc and ZnOPPC. Also in the same solvent phototransformation rather than photobleaching was observed for ZnOPPc. Split Q band in the emission and excitation spectra of ZnOPPc was observed in some solvents and this is explained in terms of the lowering of symmetry following excitation.
- Full Text:
- Date Issued: 2003
- Authors: Ogunsipe, Abimbola Olukayode , Maree, D , Nyokong, Tebello
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6586 , http://hdl.handle.net/10962/d1004162 , http://dx.doi.org/10.1016/S0022-2860(03)00155-8
- Description: The effects of solvents on the singlet oxygen, photobleaching and fluorescence quantum yields for zinc phthalocyanine (ZnPc) and its derivatives; (pyridino)zinc phthalocyanine ((py)ZnPc), zinc octaphenoxyphthalocyanine (ZnOPPc) and zinc octaestronephthalocyanine (ZnOEPc), is presented. The effects of the solvents on the ground state spectra are also discussed. The largest red shift of the Q band was observed in aromatic solvents, the highest shift being observed for 1-chloronaphthalene. Higher singlet fluorescence quantum yields were observed in THF for ZnPc and ZnOPPC. Also in the same solvent phototransformation rather than photobleaching was observed for ZnOPPc. Split Q band in the emission and excitation spectra of ZnOPPc was observed in some solvents and this is explained in terms of the lowering of symmetry following excitation.
- Full Text:
- Date Issued: 2003
South African research in the hydrological sciences: 1999-2002
- Hughes, Denis A, Ashton, P, Gorgons, A, Jewitt, G P W, Schulze, R, Smithers, J, Pegram, G, Dube, R
- Authors: Hughes, Denis A , Ashton, P , Gorgons, A , Jewitt, G P W , Schulze, R , Smithers, J , Pegram, G , Dube, R
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7074 , http://hdl.handle.net/10962/d1009531
- Description: The principal activities of South African researchers in hydrology and water resources during the reporting period have been concerned with ground- and surface-water interactions, rainfall-runoff modelling, the establishment of improved regional water resource databases, the management of transboundary water resource systems, the ecological reserve, and quantifying the impacts of streamflow reduction activities. Most of these studies have focused on supporting the radically new provisions of the National Water Act of 1998.
- Full Text:
- Date Issued: 2003
- Authors: Hughes, Denis A , Ashton, P , Gorgons, A , Jewitt, G P W , Schulze, R , Smithers, J , Pegram, G , Dube, R
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7074 , http://hdl.handle.net/10962/d1009531
- Description: The principal activities of South African researchers in hydrology and water resources during the reporting period have been concerned with ground- and surface-water interactions, rainfall-runoff modelling, the establishment of improved regional water resource databases, the management of transboundary water resource systems, the ecological reserve, and quantifying the impacts of streamflow reduction activities. Most of these studies have focused on supporting the radically new provisions of the National Water Act of 1998.
- Full Text:
- Date Issued: 2003
Studying the impact of ocean eddies on the ecosystem of the Prince Edward Islands: DEIMEC ll
- Pakhomov, E A, Ansorge, Isabelle J, Kaehler, Sven, Vumazonke, Lukhanyiso U, Gulekana, K, Bushula, T, Balt, C, Paul, D, Hargey, N, Stewart, H, Chang, N, Furno, L, Mkatshwa, S, Visser, C, Lutjeharms, Johan R E, Hayes-Foley, P
- Authors: Pakhomov, E A , Ansorge, Isabelle J , Kaehler, Sven , Vumazonke, Lukhanyiso U , Gulekana, K , Bushula, T , Balt, C , Paul, D , Hargey, N , Stewart, H , Chang, N , Furno, L , Mkatshwa, S , Visser, C , Lutjeharms, Johan R E , Hayes-Foley, P
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6932 , http://hdl.handle.net/10962/d1011952
- Description: The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity.
- Full Text:
- Date Issued: 2003
- Authors: Pakhomov, E A , Ansorge, Isabelle J , Kaehler, Sven , Vumazonke, Lukhanyiso U , Gulekana, K , Bushula, T , Balt, C , Paul, D , Hargey, N , Stewart, H , Chang, N , Furno, L , Mkatshwa, S , Visser, C , Lutjeharms, Johan R E , Hayes-Foley, P
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6932 , http://hdl.handle.net/10962/d1011952
- Description: The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity.
- Full Text:
- Date Issued: 2003
Studying the impact of ocean eddies on the ecosystem of the Prince Edward Islands: DEIMEC ll
- Pakhomov, E A, Ansorge, Isabelle J, Kaehler, S
- Authors: Pakhomov, E A , Ansorge, Isabelle J , Kaehler, S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7132 , http://hdl.handle.net/10962/d1011774
- Description: The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity.
- Full Text:
- Date Issued: 2003
- Authors: Pakhomov, E A , Ansorge, Isabelle J , Kaehler, S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:7132 , http://hdl.handle.net/10962/d1011774
- Description: The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity.
- Full Text:
- Date Issued: 2003
Teenage pregnancy and the construction of adolescence : scientific literature in South Africa
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6258 , http://hdl.handle.net/10962/d1007876 , http://journals.sagepub.com/doi/10.1177/0907568203104003
- Description: The depiction of teenage pregnancy as a social problem relies on the assumption of adolescence as a separable stage of development. Utilising a Derridian framework, I analyse how the dominant construction of adolescence as a transitional stage: (1) acts as an attempt to decide the undecidable (viz. the adolescent who is neither child nor adult, but simultaneously both) – an attempt which collapses in the face of teenage pregnancy; (2) relies on the ideal adult as the endpoint of development, and (3) has effects in terms of gendered and expert/parent/adolescent power relations.
- Full Text:
- Date Issued: 2003
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6258 , http://hdl.handle.net/10962/d1007876 , http://journals.sagepub.com/doi/10.1177/0907568203104003
- Description: The depiction of teenage pregnancy as a social problem relies on the assumption of adolescence as a separable stage of development. Utilising a Derridian framework, I analyse how the dominant construction of adolescence as a transitional stage: (1) acts as an attempt to decide the undecidable (viz. the adolescent who is neither child nor adult, but simultaneously both) – an attempt which collapses in the face of teenage pregnancy; (2) relies on the ideal adult as the endpoint of development, and (3) has effects in terms of gendered and expert/parent/adolescent power relations.
- Full Text:
- Date Issued: 2003
The Boers and the Anglo-Boer War (1899-1902) in the twentieth-century moral imaginary
- Authors: Van Wyk Smith, Malvern
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6120 , http://hdl.handle.net/10962/d1004700
- Description: In 1891 Lord Randolph Churchill, father of the more famous Winston, visited South Africa and the soon-to-be Rhodesia on a trip that was intended to combine big-game hunting with the even more exciting prospects of entering the gold mining business. During the eight months of the visit, Churchill contributed a series of letters to the Daily Graphic on his thoughts and experiences, in one of which he had this to say about the Boers: The Boer farmer personifies useless idleness. Occupying a farm of from six thousand to ten thousand acres, he contents himself with raising a herd of a few hundred head of cattle, which are left almost entirely to the care of the natives whom he employs. It may be asserted, generally with truth, that he never plants a tree, never digs a well, never makes a road, never grows a blade of corn…. He passes his day doing absolutely nothing beyond smoking and drinking coffee. He is perfectly uneducated. With the exception of the Bible, every word of which in its most literal interpretation he believes with fanatical credulity, he never opens a book, he never even reads a newspaper. His simple ignorance is unfathomable, and this in stolid composure he shares with his wife, his sons, his daughters, being proud that his children should grow up as ignorant, as uncultivated, as hopelessly unprogressive as himself. In the winter time he moves with his herd of cattle into the better pastures and milder climate of the low country veldt, and lives as idly and uselessly in his waggon as he does in his farmhouse. The summer sees him returning home, and so on [sic], year after year, generation after generation, the Boer farmer drags out the most ignoble existence ever experienced by a race with any pretensions to civilization. (94–95) The piece caused an outcry, and when a year later Churchill republished the letters as Men, Mines and Animals in South Africa (1892), he attempted to exonerate himself by claiming that these views were intended “to be exclusively confined to…the Dutch population of the Transvaal,” not “generally to the Dutch in South Africa” and went on: “The Dutch settlers in Cape Colony are as worthy of praise as their relatives, the Transvaal Boers, are of blame. The former, loyal, thrifty, industrious, hospitable, liberal are and will, I trust, remain the back-bone of our great colony at the Cape of Good Hope”
- Full Text:
- Date Issued: 2003
- Authors: Van Wyk Smith, Malvern
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6120 , http://hdl.handle.net/10962/d1004700
- Description: In 1891 Lord Randolph Churchill, father of the more famous Winston, visited South Africa and the soon-to-be Rhodesia on a trip that was intended to combine big-game hunting with the even more exciting prospects of entering the gold mining business. During the eight months of the visit, Churchill contributed a series of letters to the Daily Graphic on his thoughts and experiences, in one of which he had this to say about the Boers: The Boer farmer personifies useless idleness. Occupying a farm of from six thousand to ten thousand acres, he contents himself with raising a herd of a few hundred head of cattle, which are left almost entirely to the care of the natives whom he employs. It may be asserted, generally with truth, that he never plants a tree, never digs a well, never makes a road, never grows a blade of corn…. He passes his day doing absolutely nothing beyond smoking and drinking coffee. He is perfectly uneducated. With the exception of the Bible, every word of which in its most literal interpretation he believes with fanatical credulity, he never opens a book, he never even reads a newspaper. His simple ignorance is unfathomable, and this in stolid composure he shares with his wife, his sons, his daughters, being proud that his children should grow up as ignorant, as uncultivated, as hopelessly unprogressive as himself. In the winter time he moves with his herd of cattle into the better pastures and milder climate of the low country veldt, and lives as idly and uselessly in his waggon as he does in his farmhouse. The summer sees him returning home, and so on [sic], year after year, generation after generation, the Boer farmer drags out the most ignoble existence ever experienced by a race with any pretensions to civilization. (94–95) The piece caused an outcry, and when a year later Churchill republished the letters as Men, Mines and Animals in South Africa (1892), he attempted to exonerate himself by claiming that these views were intended “to be exclusively confined to…the Dutch population of the Transvaal,” not “generally to the Dutch in South Africa” and went on: “The Dutch settlers in Cape Colony are as worthy of praise as their relatives, the Transvaal Boers, are of blame. The former, loyal, thrifty, industrious, hospitable, liberal are and will, I trust, remain the back-bone of our great colony at the Cape of Good Hope”
- Full Text:
- Date Issued: 2003
The conjugalisation of reproduction in South African teenage pregnancy literature
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6266 , http://hdl.handle.net/10962/d1008265 , https://orcid.org/0000-0003-0992-3525
- Description: The “conjugalisation of reproduction”, in which childbearing is legitimated only within a marital alliance, underlies some of the pathologisation of the single, female-headed household in the pre-democracy South African teenage pregnancy literature. I utilise a poststructural feminist framework that draws on elements of Derrida’s and Foucault’s work to analyse the conjugalisation of reproduction in South African research. The conjugalisation of reproduction relies on (1) the insidious “unwed” signifier which interpenetrates the term “teenage pregnancy”, allowing the scientific censure of non-marital adolescent re-production without the invocation of moralisation, and (2) the fixation of the husband-wife and parents-children axes of alliance as the main elements for the deployment of sexuality and reproduction in the form of the family. Pregnant teenagers are, in Derridean terms, undecidables: they are neither children (owing to their reproductive status) nor adults (owing to their age), but simultaneously both. Marriage is the authority that decides them, allowing them to join the ranks of adult reproductive subjects.
- Full Text:
- Date Issued: 2003
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6266 , http://hdl.handle.net/10962/d1008265 , https://orcid.org/0000-0003-0992-3525
- Description: The “conjugalisation of reproduction”, in which childbearing is legitimated only within a marital alliance, underlies some of the pathologisation of the single, female-headed household in the pre-democracy South African teenage pregnancy literature. I utilise a poststructural feminist framework that draws on elements of Derrida’s and Foucault’s work to analyse the conjugalisation of reproduction in South African research. The conjugalisation of reproduction relies on (1) the insidious “unwed” signifier which interpenetrates the term “teenage pregnancy”, allowing the scientific censure of non-marital adolescent re-production without the invocation of moralisation, and (2) the fixation of the husband-wife and parents-children axes of alliance as the main elements for the deployment of sexuality and reproduction in the form of the family. Pregnant teenagers are, in Derridean terms, undecidables: they are neither children (owing to their reproductive status) nor adults (owing to their age), but simultaneously both. Marriage is the authority that decides them, allowing them to join the ranks of adult reproductive subjects.
- Full Text:
- Date Issued: 2003
The diet of a small group of extralimital giraffe
- Parker, Daniel M, Bernard, Ric T F, Colvin, S A
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
The experience of being diagnosed with a psychiatric disorder: living the label
- Knight, Zelda G, Bradfield, Bruce
- Authors: Knight, Zelda G , Bradfield, Bruce
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6262 , http://hdl.handle.net/10962/d1007880
- Description: Informed by the investigative thrust of phenomenological inquiry and the 'phenomenology of intersubjectivity', the overarching aim of this article is to provide an accurate illumination of the experience of being diagnosed with a psychiatric disorder, and thus being 'a labelled individual'. This article is based on research that sought to understand the impact of the psychiatric label upon labelled individuals interpersonal and intersubjective presence as experienced outside the psychiatric institution. The principle question asked was: "What is the experience of being a labelled individual in the world?". It was discovered that psychiatric labelling unfolds as a disconnection and dislocation from co-existence with others. Moreover, labelling had the effect of robbing such individuals of their subjectivity, rendering them lonely, misunderstood and viewed as somehow defective, disabled and wrong.
- Full Text:
- Date Issued: 2003
- Authors: Knight, Zelda G , Bradfield, Bruce
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6262 , http://hdl.handle.net/10962/d1007880
- Description: Informed by the investigative thrust of phenomenological inquiry and the 'phenomenology of intersubjectivity', the overarching aim of this article is to provide an accurate illumination of the experience of being diagnosed with a psychiatric disorder, and thus being 'a labelled individual'. This article is based on research that sought to understand the impact of the psychiatric label upon labelled individuals interpersonal and intersubjective presence as experienced outside the psychiatric institution. The principle question asked was: "What is the experience of being a labelled individual in the world?". It was discovered that psychiatric labelling unfolds as a disconnection and dislocation from co-existence with others. Moreover, labelling had the effect of robbing such individuals of their subjectivity, rendering them lonely, misunderstood and viewed as somehow defective, disabled and wrong.
- Full Text:
- Date Issued: 2003
The inception phase of a case study of outcomes - based education assessment policy in the Human and Social Sciences Learning Area of C2005
- Authors: Wilmot, P Dianne
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6107 , http://hdl.handle.net/10962/d1009736
- Description: This article describes the Inception Phase (January to December 2002) of an ongoing research project focused on the Grade 9 Learning Area of Human and Social Sciences of Curriculum 2005. The case study involves a dynamic interaction between a university lecturer, playing the role of 'outside facilitator', and the History and Geography teachers at two independent schools. The article describes how teachers in a given context respond to outcomes-based education assessment policy, and the tools and processes they use to develop the deep understanding inferred by policy (Republic of South Africa, 2000) to implement change in a meaningful way. The article consists of three sections. The first contextualises significant events which foregrounded and provided the impetus for the research project. It provides an overview of the theory informing the research and the goals of the research. The second analyses in narrative form the various stages of the Inception Phase. It describes a process of curriculum development which has involved the development of criterion- referenced assessment rubrics, a Learner and Curriculum Profile, and an audit of current assessment practices in History and Geography at the two schools. The article illuminates the time and effort necessary for creative and systemic curriculum innovation. The final section synthesizes the information gathered.
- Full Text:
- Date Issued: 2003
- Authors: Wilmot, P Dianne
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6107 , http://hdl.handle.net/10962/d1009736
- Description: This article describes the Inception Phase (January to December 2002) of an ongoing research project focused on the Grade 9 Learning Area of Human and Social Sciences of Curriculum 2005. The case study involves a dynamic interaction between a university lecturer, playing the role of 'outside facilitator', and the History and Geography teachers at two independent schools. The article describes how teachers in a given context respond to outcomes-based education assessment policy, and the tools and processes they use to develop the deep understanding inferred by policy (Republic of South Africa, 2000) to implement change in a meaningful way. The article consists of three sections. The first contextualises significant events which foregrounded and provided the impetus for the research project. It provides an overview of the theory informing the research and the goals of the research. The second analyses in narrative form the various stages of the Inception Phase. It describes a process of curriculum development which has involved the development of criterion- referenced assessment rubrics, a Learner and Curriculum Profile, and an audit of current assessment practices in History and Geography at the two schools. The article illuminates the time and effort necessary for creative and systemic curriculum innovation. The final section synthesizes the information gathered.
- Full Text:
- Date Issued: 2003
The prevalence of use and value of wild edible herbs in South Africa
- Authors: Shackleton, Charlie M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6652 , http://hdl.handle.net/10962/d1007063
- Description: The prevalence of use and commercial value of wild edible herbs in South Africa is examined from four recent quantitative studies at eight different sites. The use of wild edible herbs was widespread in rural communities, with over 90% of households using them in all but one sample site. Mean frequency of use in season was generally between two and five times per week, with a mean of four times across all sites. But many households consume them daily. Use in winter was less than in summer. The mass of wild edible herbs consumed ranged from 12 kg to over 130 kg per household per year. Local (farm-gate) prices ranged from R2.65 to R72 per kilogram, but were generally between R30 and R40 per kg. Direct-use value to consuming households ranged from R85 to almost R5000 across the eight sites, with a mean of R1020 per user household per year. Although harvesting of wild herbs takes time, the high gross direct-use value represents a considerable saving on having to purchase commercial alternatives. Key species differ from place to place both in availability and use, and include both indigenous and exotic species. Commonly used genera include Amaranthus, Bidens, Chenopodium, Cleome, Corchorus, and Momordica. The use, value and trade in wild edible herbs currently receives no recognition in land and agrarian reform policies. It is imperative that this be addressed, and the relationships between rural livelihoods, use of wild edible herbs, food security, and land and resource tenure be clarified, and debated within the policy forums around different models for, and delivery of, agrarian reform and rural development.
- Full Text:
- Date Issued: 2003
- Authors: Shackleton, Charlie M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6652 , http://hdl.handle.net/10962/d1007063
- Description: The prevalence of use and commercial value of wild edible herbs in South Africa is examined from four recent quantitative studies at eight different sites. The use of wild edible herbs was widespread in rural communities, with over 90% of households using them in all but one sample site. Mean frequency of use in season was generally between two and five times per week, with a mean of four times across all sites. But many households consume them daily. Use in winter was less than in summer. The mass of wild edible herbs consumed ranged from 12 kg to over 130 kg per household per year. Local (farm-gate) prices ranged from R2.65 to R72 per kilogram, but were generally between R30 and R40 per kg. Direct-use value to consuming households ranged from R85 to almost R5000 across the eight sites, with a mean of R1020 per user household per year. Although harvesting of wild herbs takes time, the high gross direct-use value represents a considerable saving on having to purchase commercial alternatives. Key species differ from place to place both in availability and use, and include both indigenous and exotic species. Commonly used genera include Amaranthus, Bidens, Chenopodium, Cleome, Corchorus, and Momordica. The use, value and trade in wild edible herbs currently receives no recognition in land and agrarian reform policies. It is imperative that this be addressed, and the relationships between rural livelihoods, use of wild edible herbs, food security, and land and resource tenure be clarified, and debated within the policy forums around different models for, and delivery of, agrarian reform and rural development.
- Full Text:
- Date Issued: 2003
The proof of the pudding: the presentation and proof of expert evidence in South Africa
- Meintjes–Van Der Walt, Lirieka
- Authors: Meintjes–Van Der Walt, Lirieka
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6338 , http://hdl.handle.net/10962/d1012403 , http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=170233
- Description: Imagine, as one may well imagine at this time of the day, a chocolate mousse, dark and delectable, or a tempting tiramasu or a perfect pavlova. How are you going to decide which is best? Yes, indeed the actual presentation of the puddings may influence your choice, but to be able to make an informed choice, you would need to taste them. Do you have to make the choice according to your own taste, or do you have to decide which should go best with your menu for your dinner party? If you have to decide which is best, you would have to be able to rank them in relation to other mousses, tiramasus or pavlovas. You need to know the ingredients, and for a professional decision you would need some knowledge of the art of cooking. Proof in the art of cooking, science, and also in law depends on the quantum and quality of evidence or data sufficient to support a conclusion. Loevinger concludes that “[p]roof ultimately depends on the ability of the human mind to make appropriate and useful distinctions and connections among data or items of evidence”.
- Full Text:
- Date Issued: 2003
- Authors: Meintjes–Van Der Walt, Lirieka
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6338 , http://hdl.handle.net/10962/d1012403 , http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=170233
- Description: Imagine, as one may well imagine at this time of the day, a chocolate mousse, dark and delectable, or a tempting tiramasu or a perfect pavlova. How are you going to decide which is best? Yes, indeed the actual presentation of the puddings may influence your choice, but to be able to make an informed choice, you would need to taste them. Do you have to make the choice according to your own taste, or do you have to decide which should go best with your menu for your dinner party? If you have to decide which is best, you would have to be able to rank them in relation to other mousses, tiramasus or pavlovas. You need to know the ingredients, and for a professional decision you would need some knowledge of the art of cooking. Proof in the art of cooking, science, and also in law depends on the quantum and quality of evidence or data sufficient to support a conclusion. Loevinger concludes that “[p]roof ultimately depends on the ability of the human mind to make appropriate and useful distinctions and connections among data or items of evidence”.
- Full Text:
- Date Issued: 2003