Above ground woody community attributes, biomass and carbon stocks along a rainfall gradient in the savannas of the central lowveld, South Africa
- Shackleton, Charlie M, Scholes, Robert J
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6658 , http://hdl.handle.net/10962/d1007079
- Description: Enumeration of carbon stocks at benchmark sites is a necessary activity in assessing the potential carbon sequestration and possible generation of credits through restoration of intensively impacted sites. However, there is a lack of empirical studies throughout much of the savannas of sub-Saharan Africa, including South Africa. We report an estimation of species specific and site biomass and carbon stocks, and general vegetation structural attributes from three protected areas along a rainfall gradient in the central lowveld, South Africa. Estimates of biomass and carbon stocks were effected through destructive sampling to establish locally derived allometric equations. There was a gradient of increasing woody density, height of the canopy, number of species, density of regenerative stems and a greater proportion of stems in small size classes from the arid locality to the mesic locality, with the semi-arid locality being intermediate. The proportion of spinescent species decreased with increasing rainfall. The mesic locality was significantly more woody than either the arid or semi-arid sites, having double the biomass, four times the density and 40% higher basal area. Above ground carbon pools were also higher; carbon stocks were approximately 9 t/ha for the arid and semi-arid sites and 18 t/ha for the mesic site.
- Full Text:
- Date Issued: 2011
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6658 , http://hdl.handle.net/10962/d1007079
- Description: Enumeration of carbon stocks at benchmark sites is a necessary activity in assessing the potential carbon sequestration and possible generation of credits through restoration of intensively impacted sites. However, there is a lack of empirical studies throughout much of the savannas of sub-Saharan Africa, including South Africa. We report an estimation of species specific and site biomass and carbon stocks, and general vegetation structural attributes from three protected areas along a rainfall gradient in the central lowveld, South Africa. Estimates of biomass and carbon stocks were effected through destructive sampling to establish locally derived allometric equations. There was a gradient of increasing woody density, height of the canopy, number of species, density of regenerative stems and a greater proportion of stems in small size classes from the arid locality to the mesic locality, with the semi-arid locality being intermediate. The proportion of spinescent species decreased with increasing rainfall. The mesic locality was significantly more woody than either the arid or semi-arid sites, having double the biomass, four times the density and 40% higher basal area. Above ground carbon pools were also higher; carbon stocks were approximately 9 t/ha for the arid and semi-arid sites and 18 t/ha for the mesic site.
- Full Text:
- Date Issued: 2011
The next decade of environmental science in South Africa: a horizon scan
- Shackleton, Charlie M, Scholes, Robert J, Vogel, Coleen, Wynberg, Rachel, Abrahamse, Tanya, Shackleton, Sheona E, Ellery, William F N, Gambiza, James
- Authors: Shackleton, Charlie M , Scholes, Robert J , Vogel, Coleen , Wynberg, Rachel , Abrahamse, Tanya , Shackleton, Sheona E , Ellery, William F N , Gambiza, James
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157124 , vital:40088 , https://doi.org/10.1080/03736245.2011.563064
- Description: Environmental systems are in constant flux, with feedbacks and non-linearities catalysed by natural trends and shocks as well as human actions. This poses challenges for sustainable management to promote human well-being. It requires environmental understanding and application that can accommodate such fluxes and pressures, as well as knowledge production systems and institutions that produce graduates with appropriate skills. In this article we consider these challenges in the South African context. Firstly, we summarise six significant environmental realisations from the last decade of environmental science internationally and question what they mean for the teaching of environmental science and research into environmental systems in South Africa in the near future. We then consider these lessons within the context of a horizon scan of near-term pressing environmental issues in South Africa. These include wateruse efficiency, poverty, food security, inequities in land and resource access, urbanisation, agrochemicals and water quality, promoting human well-being and economic adaptability in the face of climate change, and imbuing stronger environmental elements and stewardship into the integrated development planning processes and outcomes. Lastly, we consider the knowledge areas and skills that environmental graduates will require to be able to confront these problems in South Africa and simultaneously contribute to international debates and understandings around the complexity of environmental systems and how to manage them.
- Full Text:
- Date Issued: 2011
- Authors: Shackleton, Charlie M , Scholes, Robert J , Vogel, Coleen , Wynberg, Rachel , Abrahamse, Tanya , Shackleton, Sheona E , Ellery, William F N , Gambiza, James
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157124 , vital:40088 , https://doi.org/10.1080/03736245.2011.563064
- Description: Environmental systems are in constant flux, with feedbacks and non-linearities catalysed by natural trends and shocks as well as human actions. This poses challenges for sustainable management to promote human well-being. It requires environmental understanding and application that can accommodate such fluxes and pressures, as well as knowledge production systems and institutions that produce graduates with appropriate skills. In this article we consider these challenges in the South African context. Firstly, we summarise six significant environmental realisations from the last decade of environmental science internationally and question what they mean for the teaching of environmental science and research into environmental systems in South Africa in the near future. We then consider these lessons within the context of a horizon scan of near-term pressing environmental issues in South Africa. These include wateruse efficiency, poverty, food security, inequities in land and resource access, urbanisation, agrochemicals and water quality, promoting human well-being and economic adaptability in the face of climate change, and imbuing stronger environmental elements and stewardship into the integrated development planning processes and outcomes. Lastly, we consider the knowledge areas and skills that environmental graduates will require to be able to confront these problems in South Africa and simultaneously contribute to international debates and understandings around the complexity of environmental systems and how to manage them.
- Full Text:
- Date Issued: 2011
Woodlands or wastelands: Examining the value of South Africa's woodlands paper
- Shackleton, Charlie M, Willis, C B, Scholes, Robert J
- Authors: Shackleton, Charlie M , Willis, C B , Scholes, Robert J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182158 , vital:43805 , xlink:href="https://hdl.handle.net/10520/EJC33869"
- Description: The savanna woodlands are the largest biome in the country, constituting one-third of South Africa. They are also home to one-quarter of the population, with 70 % of the former homelands being in the savanna biome. Consequently, they have the potential to make a marked contribution to the national economy, both in the formal and informal sector. They are also valuable on a national scale in terms of the ecosystem services they provide, such as carbon storage, biodiversity and water yield. Until recently the real and potential values attached to South Africa's savannas have not been recognised in policy fora and government institutions. Recent policy changes, especially the National Forestry Action Programme and the National Forest Act, have attempted to remedy this situation. These policies have not filtered down to land owners and managers, nor have they resulted in a redirection of government resources. Thus, large areas remain subject to unsustainable use. It is necessary that the true value of woodlands be determined and acknowledged as a stimulus to government agencies, the private sector and local users to use this valuable resource sustainably.
- Full Text:
- Date Issued: 2001
- Authors: Shackleton, Charlie M , Willis, C B , Scholes, Robert J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182158 , vital:43805 , xlink:href="https://hdl.handle.net/10520/EJC33869"
- Description: The savanna woodlands are the largest biome in the country, constituting one-third of South Africa. They are also home to one-quarter of the population, with 70 % of the former homelands being in the savanna biome. Consequently, they have the potential to make a marked contribution to the national economy, both in the formal and informal sector. They are also valuable on a national scale in terms of the ecosystem services they provide, such as carbon storage, biodiversity and water yield. Until recently the real and potential values attached to South Africa's savannas have not been recognised in policy fora and government institutions. Recent policy changes, especially the National Forestry Action Programme and the National Forest Act, have attempted to remedy this situation. These policies have not filtered down to land owners and managers, nor have they resulted in a redirection of government resources. Thus, large areas remain subject to unsustainable use. It is necessary that the true value of woodlands be determined and acknowledged as a stimulus to government agencies, the private sector and local users to use this valuable resource sustainably.
- Full Text:
- Date Issued: 2001
Impact of fire frequency on woody community structure and soil nutrients in the Kruger National Park
- Shackleton, Charlie M, Scholes, Robert J
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181874 , vital:43776 , xlink:href="https://doi.org/10.4102/koedoe.v43i1.210"
- Description: Although fire is recognised as an important determinant of the structure and function of South African savannas, there are few studies of long-term impacts. Controlled burning blocks of contrasting fire season and frequency have been maintained throughout the Kruger National Park for almost 50 years. This paper reports on a quantitative study of the Satara plots to determine the long-term impacts of fire frequency on woody community structure and soil nutrients. Increasing fire frequency significantly decreased woody plant basal area, biomass, density, height, and mean stem circumference. The number of stems per plant and the proportion of regenerative stems increased with increasing fire frequency. Effects on species richness of woody plants were inconsistent. There were no significant differences attributable to fire frequency for any of the soil variables except organic matter and magnesium. Organic carbon was highest in the fire exclusion treatment and lowest in soils from plots burnt triennially. Magnesium levels were greatest in the annually burnt soils and least in the triennial plots.
- Full Text:
- Date Issued: 2000
Impact of fire frequency on woody community structure and soil nutrients in the Kruger National Park
- Authors: Shackleton, Charlie M , Scholes, Robert J
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181874 , vital:43776 , xlink:href="https://doi.org/10.4102/koedoe.v43i1.210"
- Description: Although fire is recognised as an important determinant of the structure and function of South African savannas, there are few studies of long-term impacts. Controlled burning blocks of contrasting fire season and frequency have been maintained throughout the Kruger National Park for almost 50 years. This paper reports on a quantitative study of the Satara plots to determine the long-term impacts of fire frequency on woody community structure and soil nutrients. Increasing fire frequency significantly decreased woody plant basal area, biomass, density, height, and mean stem circumference. The number of stems per plant and the proportion of regenerative stems increased with increasing fire frequency. Effects on species richness of woody plants were inconsistent. There were no significant differences attributable to fire frequency for any of the soil variables except organic matter and magnesium. Organic carbon was highest in the fire exclusion treatment and lowest in soils from plots burnt triennially. Magnesium levels were greatest in the annually burnt soils and least in the triennial plots.
- Full Text:
- Date Issued: 2000
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