An Assessment of the Effect of Rotenone on Selected Non-Target Aquatic Fauna
- Dalu, Tatenda, Wasserman, Ryan J, Jordaan, Martine, Froneman, P William, Froneman, Pierre William, Weyl, Olaf L F
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Jordaan, Martine , Froneman, P William , Froneman, Pierre William , Weyl, Olaf L F
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124240 , vital:35579 , https://doi.org/10.1371/journal.pone.0142140.g001
- 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 zooplank- ton would be more susceptible to rote none 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 par- ticularly 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, P William , Froneman, Pierre William , Weyl, Olaf L F
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124240 , vital:35579 , https://doi.org/10.1371/journal.pone.0142140.g001
- 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 zooplank- ton would be more susceptible to rote none 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 par- ticularly 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
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
Fish predation regimes modify benthic diatom community structures: experimental evidence from an in situ mesocosm study
- Wasserman, Ryan J, Vink, Tim J F, Dalu, Tatenda, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Dalu, Tatenda , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68052 , vital:29190 , https://doi.org/10.1111/aec.12255
- Description: Publisher version , Diatoms are important primary producers in shallow water environments. Few studies have assessed the importance of biological interactions in structuring these communities. In the present study, benthic diatom community structure in relation to manipulated food webs was assessed using in situ mesocosms, whereby predator-free environments and environments comprising two different fish species were assessed. Zooplankton abundance, settled algal biomass and the diatom community were monitored over a 12‐day period across each of the three trophic scenarios. Differences among treatments over time were observed in zooplankton abundances, particularly copepods. Similarly, the benthic diatom community structure changed significantly over time across the three trophic treatments. However, no differences in total algal biomass were found among treatments. This was likely the result of non‐diatom phytoplankton contributions. We propose that the benthic diatom community structure within the mesocosms was influenced by trophic cascades and potentially through direct consumption by the fish. The study highlights that not only are organisms at the base of the food web affected by predators at the top of the food web, but that predator identity is potentially an important consideration for predator–prey interaction outcomes with consequences for multiple trophic levels.
- Full Text: false
- Date Issued: 2015
- Authors: Wasserman, Ryan J , Vink, Tim J F , Dalu, Tatenda , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68052 , vital:29190 , https://doi.org/10.1111/aec.12255
- Description: Publisher version , Diatoms are important primary producers in shallow water environments. Few studies have assessed the importance of biological interactions in structuring these communities. In the present study, benthic diatom community structure in relation to manipulated food webs was assessed using in situ mesocosms, whereby predator-free environments and environments comprising two different fish species were assessed. Zooplankton abundance, settled algal biomass and the diatom community were monitored over a 12‐day period across each of the three trophic scenarios. Differences among treatments over time were observed in zooplankton abundances, particularly copepods. Similarly, the benthic diatom community structure changed significantly over time across the three trophic treatments. However, no differences in total algal biomass were found among treatments. This was likely the result of non‐diatom phytoplankton contributions. We propose that the benthic diatom community structure within the mesocosms was influenced by trophic cascades and potentially through direct consumption by the fish. The study highlights that not only are organisms at the base of the food web affected by predators at the top of the food web, but that predator identity is potentially an important consideration for predator–prey interaction outcomes with consequences for multiple trophic levels.
- Full Text: false
- Date Issued: 2015
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