A call to halt destructive, illegal mining in Zimbabwe
- Dalu, Mwazvita T B, Wasserman, Ryan J, Dalu, Tatenda
- Authors: Dalu, Mwazvita T B , Wasserman, Ryan J , Dalu, Tatenda
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/480355 , vital:78434 , https://hdl.handle.net/10520/EJC-b45d9ad6
- Description: Amidst the socio-economic meltdown in Zimbabwe, increased illegal mining activities on recently discovered diamond and gold deposits have given local people a source of livelihood. The problem of illegal gold mining is fast spreading through the Eastern Highlands and other parts of the country, as hundreds of artisanal gold miners swarm to the area, tearing up natural forests and plantations. Illegal mining operations are now rampant in the Chimanimani Mountains, a narrow belt located on the eastern Zimbabwean/western Mozambican border. The hilly and generally inaccessible nature of these mountains has preserved much of the native flora and fauna, including some endemic or near endemic animals and plants, and thus they are an important habitat. The highlands are also a crucial international catchment and a major water source for thousands of families dependent on agriculture and fishing for their livelihoods. However, with an estimated 400 000 miners now operating illegally in Zimbabwe, the cumulative mining activities represent a major threat to people’s livelihood security and to the integrity of this crucial catchment, habitat and associated river systems.
- Full Text:
- Date Issued: 2017
- Authors: Dalu, Mwazvita T B , Wasserman, Ryan J , Dalu, Tatenda
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/480355 , vital:78434 , https://hdl.handle.net/10520/EJC-b45d9ad6
- Description: Amidst the socio-economic meltdown in Zimbabwe, increased illegal mining activities on recently discovered diamond and gold deposits have given local people a source of livelihood. The problem of illegal gold mining is fast spreading through the Eastern Highlands and other parts of the country, as hundreds of artisanal gold miners swarm to the area, tearing up natural forests and plantations. Illegal mining operations are now rampant in the Chimanimani Mountains, a narrow belt located on the eastern Zimbabwean/western Mozambican border. The hilly and generally inaccessible nature of these mountains has preserved much of the native flora and fauna, including some endemic or near endemic animals and plants, and thus they are an important habitat. The highlands are also a crucial international catchment and a major water source for thousands of families dependent on agriculture and fishing for their livelihoods. However, with an estimated 400 000 miners now operating illegally in Zimbabwe, the cumulative mining activities represent a major threat to people’s livelihood security and to the integrity of this crucial catchment, habitat and associated river systems.
- Full Text:
- Date Issued: 2017
Trophic isotopic carbon variation increases with pond’s hydroperiod: evidence from an Austral ephemeral ecosystem
- Dalu, Tatenda, Wasserman, Ryan J, Froneman, P William, Weyl, Olaf, L F
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Froneman, P William , Weyl, Olaf, L F
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/467244 , vital:76844 , https://doi.org/10.1038/s41598-017-08026-6
- Description: Trophic variation in food web structure occurs among and within ecosystems. The magnitude of variation, however, differs from system to system. In ephemeral pond ecosystems, temporal dynamics are relatively more important than in many systems given that hydroperiod is the ultimate factor determining the presence of an aquatic state. Here, using stable isotopes we tested for changes in trophic chain length and shape over time in these dynamic aquatic ecosystems. We found that lower and intermediate trophic level structure increased over time. We discuss these findings within the context of temporal environmental stability. The dynamic nature of these ephemeral systems seems to be conducive to greater levels of intermediate and lower trophic level diversity, with omnivorous traits likely being advantageous.
- Full Text:
- Date Issued: 2017
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Froneman, P William , Weyl, Olaf, L F
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/467244 , vital:76844 , https://doi.org/10.1038/s41598-017-08026-6
- Description: Trophic variation in food web structure occurs among and within ecosystems. The magnitude of variation, however, differs from system to system. In ephemeral pond ecosystems, temporal dynamics are relatively more important than in many systems given that hydroperiod is the ultimate factor determining the presence of an aquatic state. Here, using stable isotopes we tested for changes in trophic chain length and shape over time in these dynamic aquatic ecosystems. We found that lower and intermediate trophic level structure increased over time. We discuss these findings within the context of temporal environmental stability. The dynamic nature of these ephemeral systems seems to be conducive to greater levels of intermediate and lower trophic level diversity, with omnivorous traits likely being advantageous.
- Full Text:
- Date Issued: 2017
Variation partitioning of benthic diatom community matrices: Effects of multiple variables on benthic diatom communities in an Austral temperate river system
- Dalu, Tatenda, Wasserman, Ryan J, Magoro, Mandla L, Mwedzi, Tongayi, Froneman, P William, Weyl, Olaf L F
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Magoro, Mandla L , Mwedzi, Tongayi , Froneman, P William , Weyl, Olaf L F
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/467182 , vital:76837 , https://doi.org/10.1016/j.scitotenv.2017.05.162
- Description: This study explores diatom community dynamics in a highly modified semi-arid temperate region river system characterised by inconsistent river flow. Various water and sediment environmental variables were assessed using a multi-faceted analysis approach to determine the spatio-temporal drivers of benthic diatom communities in the river system. Overall, the diatom community was generally dominated by pollution tolerant species, reflecting the anthropogenic intensity and activities on the river system. Diatom community composition was found to be largely determined by water column chemistry variables particularly nutrient concentrations in comparison to sediment chemistry and physical variables. Strong seasonal diatom species composition was also observed and this was driven by strong seasonal variations in nutrient loads and metal concentrations, a result of the variable water flow across the two seasons. However, the greater temporal variation in communities was observed in the smaller systems with the mainstream river system being more homogenous over time. In addition, diatom community composition and environmental variables were found to be different and more pronounced between streams and mainstream sites, than between canals and streams. The study highlights the complex interaction between water column, sediment and physical variables in determining the diatom species composition in small river systems. It also highlights the importance of river flow inconsistency as an indirect variable that alters primary drivers such as nutrient concentrations in the water column and heavy metal levels in the sediment.
- Full Text:
- Date Issued: 2017
- Authors: Dalu, Tatenda , Wasserman, Ryan J , Magoro, Mandla L , Mwedzi, Tongayi , Froneman, P William , Weyl, Olaf L F
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/467182 , vital:76837 , https://doi.org/10.1016/j.scitotenv.2017.05.162
- Description: This study explores diatom community dynamics in a highly modified semi-arid temperate region river system characterised by inconsistent river flow. Various water and sediment environmental variables were assessed using a multi-faceted analysis approach to determine the spatio-temporal drivers of benthic diatom communities in the river system. Overall, the diatom community was generally dominated by pollution tolerant species, reflecting the anthropogenic intensity and activities on the river system. Diatom community composition was found to be largely determined by water column chemistry variables particularly nutrient concentrations in comparison to sediment chemistry and physical variables. Strong seasonal diatom species composition was also observed and this was driven by strong seasonal variations in nutrient loads and metal concentrations, a result of the variable water flow across the two seasons. However, the greater temporal variation in communities was observed in the smaller systems with the mainstream river system being more homogenous over time. In addition, diatom community composition and environmental variables were found to be different and more pronounced between streams and mainstream sites, than between canals and streams. The study highlights the complex interaction between water column, sediment and physical variables in determining the diatom species composition in small river systems. It also highlights the importance of river flow inconsistency as an indirect variable that alters primary drivers such as nutrient concentrations in the water column and heavy metal levels in the sediment.
- Full Text:
- Date Issued: 2017
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