An assessment of the effect of rotenone on selected non-target aquatic fauna:
- Dalu, Tatenda, Wasserman, Ryan J, Jordaan, Martine, Froneman, P William, Weyl, Olaf L F
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Jordaan, Martine , Froneman, P William , Weyl, Olaf L F
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143247 , vital:38214 , https://doi.org/10.1371/journal.pone.0142140
- Description: Rotenone, a naturally occurring ketone, is widely employed for the management of invasive fish species. The use of rotenone poses serious challenges to conservation practitioners due to its impacts on non-target organisms including amphibians and macroinvertebrates. Using laboratory studies, we investigated the effects of different rotenone concentrations (0, 12.5, 25, 37.5, 50, 100 μg L-1) on selected invertebrate groups; Aeshnidae, Belostomatids, Decapods, Ephemeroptera, Pulmonata and zooplankton over a period of 18 hours. Based on field observations and body size, we hypothesized that Ephemeropterans and zooplankton would be more susceptible to rotenone than Decapods, Belostomatids and snails.
- Full Text:
- Date Issued: 2015
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Jordaan, Martine , Froneman, P William , Weyl, Olaf L F
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143247 , vital:38214 , https://doi.org/10.1371/journal.pone.0142140
- Description: Rotenone, a naturally occurring ketone, is widely employed for the management of invasive fish species. The use of rotenone poses serious challenges to conservation practitioners due to its impacts on non-target organisms including amphibians and macroinvertebrates. Using laboratory studies, we investigated the effects of different rotenone concentrations (0, 12.5, 25, 37.5, 50, 100 μg L-1) on selected invertebrate groups; Aeshnidae, Belostomatids, Decapods, Ephemeroptera, Pulmonata and zooplankton over a period of 18 hours. Based on field observations and body size, we hypothesized that Ephemeropterans and zooplankton would be more susceptible to rotenone than Decapods, Belostomatids and snails.
- Full Text:
- Date Issued: 2015
An Assessment of the Effect of Rotenone on Selected Non-Target Aquatic Fauna: Reflections on Henri Lefebre, Urban Theory and the Politics of Scale
- Dalu, Tatenda, Wasserman, Ryan J, Jordaan, Martine, Froneman, Pierre William
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Jordaan, Martine , Froneman, Pierre William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70425 , vital:29654 , https://doi.org/10.1371/journal.pone.0142140
- Description: Rotenone, a naturally occurring ketone, is widely employed for the management of invasive fish species. The use of rotenone poses serious challenges to conservation practitioners due to its impacts on non-target organisms including amphibians and macroinvertebrates. Using laboratory studies, we investigated the effects of different rotenone concentrations (0,12.5, 25, 37.5, 50, 100 μg L-1) on selected invertebrate groups; Aeshnidae, Belostomatids, Decapods, Ephemeroptera, Pulmonata and zooplankton over a period of 18 hours. Based on field observations and body size, we hypothesized that Ephemeropterans and zooplankton would be more susceptible to rotenone than Decapods, Belostomatids and snails. Experimental results supported this hypothesis and mortality and behaviour effects varied considerably between taxa, ranging from no effect (crab Potamonuates sidneyi) to 100% mortality (Daphnia pulex and Paradiaptomus lamellatus). Planktonic invertebrates were particularly sensitive to rotenone even at very low concentrations. Future research should investigate the recovery time of invertebrate communities after the application of rotenone and conduct field assessments assessing the longer term effects of rotenone exposure on the population dynamics of those less sensitive organisms.
- Full Text:
- Date Issued: 2015
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Jordaan, Martine , Froneman, Pierre William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70425 , vital:29654 , https://doi.org/10.1371/journal.pone.0142140
- Description: Rotenone, a naturally occurring ketone, is widely employed for the management of invasive fish species. The use of rotenone poses serious challenges to conservation practitioners due to its impacts on non-target organisms including amphibians and macroinvertebrates. Using laboratory studies, we investigated the effects of different rotenone concentrations (0,12.5, 25, 37.5, 50, 100 μg L-1) on selected invertebrate groups; Aeshnidae, Belostomatids, Decapods, Ephemeroptera, Pulmonata and zooplankton over a period of 18 hours. Based on field observations and body size, we hypothesized that Ephemeropterans and zooplankton would be more susceptible to rotenone than Decapods, Belostomatids and snails. Experimental results supported this hypothesis and mortality and behaviour effects varied considerably between taxa, ranging from no effect (crab Potamonuates sidneyi) to 100% mortality (Daphnia pulex and Paradiaptomus lamellatus). Planktonic invertebrates were particularly sensitive to rotenone even at very low concentrations. Future research should investigate the recovery time of invertebrate communities after the application of rotenone and conduct field assessments assessing the longer term effects of rotenone exposure on the population dynamics of those less sensitive organisms.
- Full Text:
- Date Issued: 2015
Teaching Mandarin in schools is another slap in the face for African languages
- Kaschula, Russell H, Nosilela, Bulelwa, Heugh, Kathleen, Hendricks, Monica, Maseko, Pamela
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
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