The microbial ecology of sulphidogenic lignocellulose degradation
- Authors: Clarke, Anna Maria
- Date: 2007
- Subjects: Microbial ecology , Lignocellulose , Sulfides , Lignin , Lignocellulose -- Biodegradation , Mines and mineral resources -- Waste disposal , Acid mine drainage
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4094 , http://hdl.handle.net/10962/d1008181
- Description: Acid mine drainage is a well known environmental pollutant, not only in South Africa, but throughout the world, and the use of microbial processes in the treatment of these wastes has been the subject of investigation over past decades. Lignocellulose packed-bed reactors have been used in passive treatment systems, and, although effective initially, they show early decline in performance while the packing material remains largely un-utilized. Little is known about this phenomenon which remains a severe constraint in the development of efficient passive mine water treatment systems. It has been proposed that the degradation pathways of the complex lignocellulose substrate may be limited in some way in these systems during the manifestation of this effect. This study has addressed the problem using a molecular microbial ecology methodology in an attempt to relate trophic functions of the microbial population to the physico-chemical data of the system. A field-scale lignocellulose packed-bed reactor located at Vryheid Coronation Colliery (Northern Kwa-Zulu Natal province, South Africa) was monitored for six years and the results showed the classic profile of performance decline related to a slowdown in sulphate reduction and alkalinity production. The reactor was decommissioned , comprehensive samples were collected along the depth profile and the microbial populations investigated by means of 16S rRNA gene methodology. The population was found to include cellulolytic Clostridia spp., CytophagaIFlavobacterlBacteroidetes, Sphingomonadaceae and as yet uncultured microorganisms related to microbiota identified in the rumen and termite gut. These are all known to be involved as primary fermenters of cellulose. Oesulphosporosinus was present as sulphate reducer. A comparison of substrata sampling and population distribution suggested that spatial and temporal gradients within the system may become established over the course of its operation. Based on these findings, a laboratory-scale reactor was constructed to simulate the performance of the packed-bed reactor under controlled experimental conditions. The laboratory-scale reactor was operated for 273 days and showed comparable performance to that in the field in both biomolecular and physicochemical data. Clearly defined trophic niches were observed. These results suggested that a sequence of events does occur in lignocellulose degradation over time. Based on the spatial and temporal column studies, a descriptive model was proposed to account for these events. It was found that fermentative organisms predominate in the inlet zone of the system using easily extractable compounds from the wood, thus providing feedstock for sulphate reduction occurring in the succeeding compartments. Production of sulphide and alkalinity appears to be involved in the enhancement of lignin degradation and this, in turn, appears to enhance access to the cellulose fraction. However, once the readily extractables are exhausted, the decline in sulphide and alkalinity production leads inexorably to a decline in the overall performance of the system as a sulphate reducing unit operation. These observations led to the proposal that with the addition of a limited amount of a readily available carbon source, such as molasses, in the initial zone of the the reactor, the ongoing generation of sulphide would be sustained and this in turn would sustain the microbial attack on the lignocellulose complex. This proposal was tested in scale-up studies and positive results indicate that the descriptive model may, to some extent, provide an account of events occurring in these systems. The work on sustaining lignocellulose degradation through the maintenance of sulphate reduction in the initial stages of the reactor flow path has led to the development of the Degrading Packed-bed Reactor concept and that, has subsequently been successfully evaluated in the field.
- Full Text:
- Date Issued: 2007
- Authors: Clarke, Anna Maria
- Date: 2007
- Subjects: Microbial ecology , Lignocellulose , Sulfides , Lignin , Lignocellulose -- Biodegradation , Mines and mineral resources -- Waste disposal , Acid mine drainage
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4094 , http://hdl.handle.net/10962/d1008181
- Description: Acid mine drainage is a well known environmental pollutant, not only in South Africa, but throughout the world, and the use of microbial processes in the treatment of these wastes has been the subject of investigation over past decades. Lignocellulose packed-bed reactors have been used in passive treatment systems, and, although effective initially, they show early decline in performance while the packing material remains largely un-utilized. Little is known about this phenomenon which remains a severe constraint in the development of efficient passive mine water treatment systems. It has been proposed that the degradation pathways of the complex lignocellulose substrate may be limited in some way in these systems during the manifestation of this effect. This study has addressed the problem using a molecular microbial ecology methodology in an attempt to relate trophic functions of the microbial population to the physico-chemical data of the system. A field-scale lignocellulose packed-bed reactor located at Vryheid Coronation Colliery (Northern Kwa-Zulu Natal province, South Africa) was monitored for six years and the results showed the classic profile of performance decline related to a slowdown in sulphate reduction and alkalinity production. The reactor was decommissioned , comprehensive samples were collected along the depth profile and the microbial populations investigated by means of 16S rRNA gene methodology. The population was found to include cellulolytic Clostridia spp., CytophagaIFlavobacterlBacteroidetes, Sphingomonadaceae and as yet uncultured microorganisms related to microbiota identified in the rumen and termite gut. These are all known to be involved as primary fermenters of cellulose. Oesulphosporosinus was present as sulphate reducer. A comparison of substrata sampling and population distribution suggested that spatial and temporal gradients within the system may become established over the course of its operation. Based on these findings, a laboratory-scale reactor was constructed to simulate the performance of the packed-bed reactor under controlled experimental conditions. The laboratory-scale reactor was operated for 273 days and showed comparable performance to that in the field in both biomolecular and physicochemical data. Clearly defined trophic niches were observed. These results suggested that a sequence of events does occur in lignocellulose degradation over time. Based on the spatial and temporal column studies, a descriptive model was proposed to account for these events. It was found that fermentative organisms predominate in the inlet zone of the system using easily extractable compounds from the wood, thus providing feedstock for sulphate reduction occurring in the succeeding compartments. Production of sulphide and alkalinity appears to be involved in the enhancement of lignin degradation and this, in turn, appears to enhance access to the cellulose fraction. However, once the readily extractables are exhausted, the decline in sulphide and alkalinity production leads inexorably to a decline in the overall performance of the system as a sulphate reducing unit operation. These observations led to the proposal that with the addition of a limited amount of a readily available carbon source, such as molasses, in the initial zone of the the reactor, the ongoing generation of sulphide would be sustained and this in turn would sustain the microbial attack on the lignocellulose complex. This proposal was tested in scale-up studies and positive results indicate that the descriptive model may, to some extent, provide an account of events occurring in these systems. The work on sustaining lignocellulose degradation through the maintenance of sulphate reduction in the initial stages of the reactor flow path has led to the development of the Degrading Packed-bed Reactor concept and that, has subsequently been successfully evaluated in the field.
- Full Text:
- Date Issued: 2007
The origins, developments, and current performance practices of African neo-traditional choral music of Southern Africa
- Authors: De Beer, Rudolf
- Date: 2007
- Subjects: Choral music -- Africa, Southern , Music -- Performance -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , DMus
- Identifier: vital:8514 , http://hdl.handle.net/10948/d1011781 , Choral music -- Africa, Southern , Music -- Performance -- Africa, Southern
- Description: This study deals with African neo-traditional choral music of sub-Saharan- and Southern Africa, with specific reference to extemporisation. The research focussed on the evolution of this music through an amalgamation of western choral music and African indigenous and traditional musical practices of sub- Saharan and Southern Africa. Specific reference to the syncretism of western music, which came to Africa through colonisation, and the way African indigenous musical traditions influenced it, is preceded by descriptions on African indigenous musical practices and western choral music traditions. The incorporation of traditional folk songs into African makwaya, or “choir music”, was inevitable. This development saw the birth of African neotraditional choral music as a formal part of many choirs’ programmes. A description of five sample choirs engaging with this music was followed by a case study on the Drakensberg Boys’ Choir. The way these choirs deal with different aspects regarding the preparation and performance of this music highlighted many parallels with African indigenous traditions. It also emphasises the important role of this music in choral performance, as well as choral education. As a genre in evolution, one aspect of this music, namely extemporisation, was studied in more detail in order to suggest another way of engaging with this music. Not only is choral extemporisation a possibility in African neo-traditional choral music of Southern Africa, but it is also a flourishing art form in Scandinavia. In Norway and Sweden it also utilises characteristics and techniques of folk music, which raised the status of this music to be a major art form. This notion prompted the suggested application of choral extemporisation to African neo-traditional choral music of Southern Africa. Even if any method of extemporisation may be utilised, it is proposed that characteristics of African sub- Saharan- and Southern African indigenous music be applied. This may result in the incorporation of more of these African indigenous elements in the neo-traditional choral music discussed than the current western harmonic emphasis. However, the suggestion is seen as a next step in the evolution of this music, which corresponds with international practices, and not to return to indigenous practices as such.
- Full Text:
- Date Issued: 2007
- Authors: De Beer, Rudolf
- Date: 2007
- Subjects: Choral music -- Africa, Southern , Music -- Performance -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , DMus
- Identifier: vital:8514 , http://hdl.handle.net/10948/d1011781 , Choral music -- Africa, Southern , Music -- Performance -- Africa, Southern
- Description: This study deals with African neo-traditional choral music of sub-Saharan- and Southern Africa, with specific reference to extemporisation. The research focussed on the evolution of this music through an amalgamation of western choral music and African indigenous and traditional musical practices of sub- Saharan and Southern Africa. Specific reference to the syncretism of western music, which came to Africa through colonisation, and the way African indigenous musical traditions influenced it, is preceded by descriptions on African indigenous musical practices and western choral music traditions. The incorporation of traditional folk songs into African makwaya, or “choir music”, was inevitable. This development saw the birth of African neotraditional choral music as a formal part of many choirs’ programmes. A description of five sample choirs engaging with this music was followed by a case study on the Drakensberg Boys’ Choir. The way these choirs deal with different aspects regarding the preparation and performance of this music highlighted many parallels with African indigenous traditions. It also emphasises the important role of this music in choral performance, as well as choral education. As a genre in evolution, one aspect of this music, namely extemporisation, was studied in more detail in order to suggest another way of engaging with this music. Not only is choral extemporisation a possibility in African neo-traditional choral music of Southern Africa, but it is also a flourishing art form in Scandinavia. In Norway and Sweden it also utilises characteristics and techniques of folk music, which raised the status of this music to be a major art form. This notion prompted the suggested application of choral extemporisation to African neo-traditional choral music of Southern Africa. Even if any method of extemporisation may be utilised, it is proposed that characteristics of African sub- Saharan- and Southern African indigenous music be applied. This may result in the incorporation of more of these African indigenous elements in the neo-traditional choral music discussed than the current western harmonic emphasis. However, the suggestion is seen as a next step in the evolution of this music, which corresponds with international practices, and not to return to indigenous practices as such.
- Full Text:
- Date Issued: 2007
The Rhodes BioSURE process and the use of sustainability indicators in the development of biological mine water treatment
- Authors: Neba, Alphonsus
- Date: 2007
- Subjects: Acid mine drainage Water -- Purification -- Biological treatment Mine water Mine water -- Purification Sewage -- Purification
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3984 , http://hdl.handle.net/10962/d1004043
- Description: Polluted waters, arising from extensive past and ongoing mining operations in South Africa, pose serious environmental threats to the limited fresh water resource. The long time periods, of decades to centuries, over which decanting mine waters may be expected to flow raises additional concerns about the sustainability of these resources. Responses to the problem have thus increasingly been directed towards the long-term sustainability of mine water treatment technologies (MWTT) as a critical indicator in both their research and development, and application. Bioprocess treatments have been considered in this regard and, among these, the Rhodes BioSURE Process has been investigated in preliminary studies using complex organic carbon wastes as the carbon source and electron donor for the central sulphate reduction unit operation. Although both the mining industry and the related statutory/regulatory authority in South Africa share public commitment to sustainability in the treatment of mine waters, no systematic mechanism has emerged to enable the application of sustainability thinking as a guiding principle in the selection and application of MWTTs, nor in the research and development undertaking. This study undertook the development of a Sustainability Indicator Framework in order to provide a systematic basis for the incorporation of sustainability objectives in MWTT bioprocess development, and specifically to use this framework as an input to the investigation of the scaleup development of the Rhodes BioSURE Process. In the development of the MWTT Sustainability Indicator Framework, an initial survey of industry thinking in this area was undertaken and, based on these outcomes, a detailed questionnaire methodology was developed in order to identify and quantify critical sustainability indicators. These included analysis of environmental, economic, social and technical indicators used in sustainability accounting practice in the industry. Statutory/regulatory sustainability targets in the same categories were derived from State of the Environment Reports (SoER) from Provincial authorities where mining is undertaken in South Africa. A synthesis of industry and SoER values was derived from weighted averages and the Sustainability Indicator Framework based on these outcomes. A Conceptual Decision-Support System, to guide the selection and development of MWTTs, was proposed and also based on these results. In the development of the Rhodes BioSURE Process the use of primary sludge (PS) had been investigated as a potential complex carbon and electron donor source. In this regard the utility operator, and sewage treatment process infrastructure, was identified as potentially meeting aspects of the sustainability objectives identified for MWTT application development. Both the Sustainability Indicator Framework and the Conceptual Decision-Support System provided inputs in the formulation of the experimental programme relating to the scale-up development of the Rhodes BioSURE Process. Based on these outcomes, a series of single- and multi-stage reactor configuration, optimisation and enzymology studies were undertaken at bench-, pilot- and technical-scale operations. These units were operated at hydraulic retention times (HRT) ranging between 22 to 72 hours and at chemical oxygen demand to sulphate ratios (COD:SO[subscript 4]) ranging between 1:1 to 2:1. Studies undertaken in fed-batch, bench-scale reactors confirmed the preliminary feasibility of using established sewage treatment infrastructure as a replacement for novel reactor configurations that had been used in the initial studies. The results further indicated that the hydrolysis of PS occurred at different rates under biosulphidogenic conditions in the different reactor configurations investigated. Scale-up of these findings in multi-stage pilot- (7.4m[superscript 3]) and technical-scale plants (680m[superscript 3]) showed comparable performances between the unit operations in terms of SO[subscript 4] and COD removal. These results indicated no apparent advantages in the uncoupling of hydrolysis and sulphate reduction in separate unit operations as had been suggested in previous studies. Scale-down/scale-up studies were undertaken in a continuously fed single-stage reactor configuration and showed that the process could be effectively operated in this way. Previous proposals that chemical and biological gradients established in the sludge bed of the Recycling Sludge Bed Reactor (RSBR) exercised an influence on the rates of substrate hydrolysis were investigated and the relative activity of α- and β-glucosidase and protease enzymes was measured. Results provided additional support for this hypothesis and it was shown that enzyme assay may also provide a useful tool in process development and monitoring studies. While sulphide recovery, following the sulphate reduction step in the BioSURE Process, was not investigated as a component of this study, the treatment of final effluent or waste spills was identified as an important sustainability requirement given the toxicity of sulphide to human and ecosystem environments. A conventional trickle filter reactor system was evaluated for this purpose and showed close to 100% oxidation to sulphate in a short contact time operating regime. Although residual COD removal was low at ~20% of influent, it is considered that high rate recycle biofilter operation could achieve the COD discharge standard of 75 mg/l. The results of the above studies provided inputs into the design, construction and commissioning of the first full-scale commercial application of the Rhodes BioSURE Process for mine wastewater treatment using sewage sludge as the carbon and electron donor source. An adjacent mine and sewage works have been linked by pipeline and an operational capacity of 10 Ml/day water treated has been established with sulphate reduced from ~1300mg/l to <200mg/l. These developments constitute a novel contribution in the mine waste water treatment field.
- Full Text:
- Date Issued: 2007
- Authors: Neba, Alphonsus
- Date: 2007
- Subjects: Acid mine drainage Water -- Purification -- Biological treatment Mine water Mine water -- Purification Sewage -- Purification
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3984 , http://hdl.handle.net/10962/d1004043
- Description: Polluted waters, arising from extensive past and ongoing mining operations in South Africa, pose serious environmental threats to the limited fresh water resource. The long time periods, of decades to centuries, over which decanting mine waters may be expected to flow raises additional concerns about the sustainability of these resources. Responses to the problem have thus increasingly been directed towards the long-term sustainability of mine water treatment technologies (MWTT) as a critical indicator in both their research and development, and application. Bioprocess treatments have been considered in this regard and, among these, the Rhodes BioSURE Process has been investigated in preliminary studies using complex organic carbon wastes as the carbon source and electron donor for the central sulphate reduction unit operation. Although both the mining industry and the related statutory/regulatory authority in South Africa share public commitment to sustainability in the treatment of mine waters, no systematic mechanism has emerged to enable the application of sustainability thinking as a guiding principle in the selection and application of MWTTs, nor in the research and development undertaking. This study undertook the development of a Sustainability Indicator Framework in order to provide a systematic basis for the incorporation of sustainability objectives in MWTT bioprocess development, and specifically to use this framework as an input to the investigation of the scaleup development of the Rhodes BioSURE Process. In the development of the MWTT Sustainability Indicator Framework, an initial survey of industry thinking in this area was undertaken and, based on these outcomes, a detailed questionnaire methodology was developed in order to identify and quantify critical sustainability indicators. These included analysis of environmental, economic, social and technical indicators used in sustainability accounting practice in the industry. Statutory/regulatory sustainability targets in the same categories were derived from State of the Environment Reports (SoER) from Provincial authorities where mining is undertaken in South Africa. A synthesis of industry and SoER values was derived from weighted averages and the Sustainability Indicator Framework based on these outcomes. A Conceptual Decision-Support System, to guide the selection and development of MWTTs, was proposed and also based on these results. In the development of the Rhodes BioSURE Process the use of primary sludge (PS) had been investigated as a potential complex carbon and electron donor source. In this regard the utility operator, and sewage treatment process infrastructure, was identified as potentially meeting aspects of the sustainability objectives identified for MWTT application development. Both the Sustainability Indicator Framework and the Conceptual Decision-Support System provided inputs in the formulation of the experimental programme relating to the scale-up development of the Rhodes BioSURE Process. Based on these outcomes, a series of single- and multi-stage reactor configuration, optimisation and enzymology studies were undertaken at bench-, pilot- and technical-scale operations. These units were operated at hydraulic retention times (HRT) ranging between 22 to 72 hours and at chemical oxygen demand to sulphate ratios (COD:SO[subscript 4]) ranging between 1:1 to 2:1. Studies undertaken in fed-batch, bench-scale reactors confirmed the preliminary feasibility of using established sewage treatment infrastructure as a replacement for novel reactor configurations that had been used in the initial studies. The results further indicated that the hydrolysis of PS occurred at different rates under biosulphidogenic conditions in the different reactor configurations investigated. Scale-up of these findings in multi-stage pilot- (7.4m[superscript 3]) and technical-scale plants (680m[superscript 3]) showed comparable performances between the unit operations in terms of SO[subscript 4] and COD removal. These results indicated no apparent advantages in the uncoupling of hydrolysis and sulphate reduction in separate unit operations as had been suggested in previous studies. Scale-down/scale-up studies were undertaken in a continuously fed single-stage reactor configuration and showed that the process could be effectively operated in this way. Previous proposals that chemical and biological gradients established in the sludge bed of the Recycling Sludge Bed Reactor (RSBR) exercised an influence on the rates of substrate hydrolysis were investigated and the relative activity of α- and β-glucosidase and protease enzymes was measured. Results provided additional support for this hypothesis and it was shown that enzyme assay may also provide a useful tool in process development and monitoring studies. While sulphide recovery, following the sulphate reduction step in the BioSURE Process, was not investigated as a component of this study, the treatment of final effluent or waste spills was identified as an important sustainability requirement given the toxicity of sulphide to human and ecosystem environments. A conventional trickle filter reactor system was evaluated for this purpose and showed close to 100% oxidation to sulphate in a short contact time operating regime. Although residual COD removal was low at ~20% of influent, it is considered that high rate recycle biofilter operation could achieve the COD discharge standard of 75 mg/l. The results of the above studies provided inputs into the design, construction and commissioning of the first full-scale commercial application of the Rhodes BioSURE Process for mine wastewater treatment using sewage sludge as the carbon and electron donor source. An adjacent mine and sewage works have been linked by pipeline and an operational capacity of 10 Ml/day water treated has been established with sulphate reduced from ~1300mg/l to <200mg/l. These developments constitute a novel contribution in the mine waste water treatment field.
- Full Text:
- Date Issued: 2007
The role of achievement motivation on the interlanguage fossilization of middle-aged English-as-a-second-language learners
- Authors: Vujisic, Zoran
- Date: 2007
- Subjects: Second language acquisition Language and languages -- Study and teaching Fossilization (Linguistics) Interlanguage (Language learning) English language -- Study and teaching -- Foreign speakers Motivation in education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2368 , http://hdl.handle.net/10962/d1003748
- Description: Second language acquisition (SLA) is seldom entirely successful with adult learners. It has been suggested that all second language (L2) learners, in the process of mastering a target language (TL), develop a linguistic system that is self-contained and different from both the learner's native language and the TL. This system is referred to as 'interlanguage' (lL). In the process of SLA, IL evolves into an ever-closer approximation of the TL, and ideally, a learner's IL should continue to advance until it becomes equivalent to the TL. However, it has been observed that somewhere in the L2 learning process, IL may reach one or more plateaus during which the development of the IL is delayed or arrested. A permanent cessation of progress toward the TL is referred to as 'fossilization'. Researchers in SLA agree that motivation is one of the key factors influencing language-learning success and studies suggest that some language learning motivation may be related to the need for achievement. The purpose of this research was to establish if adult ESL learners are aware of fossilization and, to examine if motivation, and more specifically achievement motivation, is a factor in IL fossilization. The participants in this study consisted of 15 ESL learners in Puerto Rico who had at least eight years of formal ESL training. The instrument used to gather information included a questionnaire to obtain demographical and qualifying data, an 'English Language Proficiency Evaluation' to determine levels of IL fossilization, a 'Measure of Achievement Motivation' to ascertain achievement motive, and individual and group interviews in order to ascertain perception(s) regarding the role of motivation on fossilization and perceptions regarding the barriers to achieving TL competency. The research demonstrated that there is a moderate to strong positive relationship between IL fossilization and achievement motivation, i.e., high achievement motive is correlated to TL competency and descending levels of achievement motive are correlated to ascending levels of IL fossilization. The findings have significant implications for both ESL learning and instruction, and suggest that not all IL fossilization may be permanent.
- Full Text:
- Date Issued: 2007
- Authors: Vujisic, Zoran
- Date: 2007
- Subjects: Second language acquisition Language and languages -- Study and teaching Fossilization (Linguistics) Interlanguage (Language learning) English language -- Study and teaching -- Foreign speakers Motivation in education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2368 , http://hdl.handle.net/10962/d1003748
- Description: Second language acquisition (SLA) is seldom entirely successful with adult learners. It has been suggested that all second language (L2) learners, in the process of mastering a target language (TL), develop a linguistic system that is self-contained and different from both the learner's native language and the TL. This system is referred to as 'interlanguage' (lL). In the process of SLA, IL evolves into an ever-closer approximation of the TL, and ideally, a learner's IL should continue to advance until it becomes equivalent to the TL. However, it has been observed that somewhere in the L2 learning process, IL may reach one or more plateaus during which the development of the IL is delayed or arrested. A permanent cessation of progress toward the TL is referred to as 'fossilization'. Researchers in SLA agree that motivation is one of the key factors influencing language-learning success and studies suggest that some language learning motivation may be related to the need for achievement. The purpose of this research was to establish if adult ESL learners are aware of fossilization and, to examine if motivation, and more specifically achievement motivation, is a factor in IL fossilization. The participants in this study consisted of 15 ESL learners in Puerto Rico who had at least eight years of formal ESL training. The instrument used to gather information included a questionnaire to obtain demographical and qualifying data, an 'English Language Proficiency Evaluation' to determine levels of IL fossilization, a 'Measure of Achievement Motivation' to ascertain achievement motive, and individual and group interviews in order to ascertain perception(s) regarding the role of motivation on fossilization and perceptions regarding the barriers to achieving TL competency. The research demonstrated that there is a moderate to strong positive relationship between IL fossilization and achievement motivation, i.e., high achievement motive is correlated to TL competency and descending levels of achievement motive are correlated to ascending levels of IL fossilization. The findings have significant implications for both ESL learning and instruction, and suggest that not all IL fossilization may be permanent.
- Full Text:
- Date Issued: 2007
The role of ants in structuring insect communities on the canopies of senegalia drepanolobium near Laikipia, Kenya
- Authors: Kuria, Simon Kamande
- Date: 2007
- Subjects: Ants -- Kenya Ants -- Behavior Insect societies -- Kenya Forest canopy ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5758 , http://hdl.handle.net/10962/d1005446
- Description: In the black cotton ecosystem of Laikipia, Kenya, four symbiotic ants coexist at a fine spatial scale on canopies of Senegalia drepanolobium. They exhibit different aggressive behaviours and modify their tree canopies differently. These diverse behaviours were expected to affect the associated canopy arthropod communities. At the Kenya long-term exclosure experiment (KLEE) and its immediate environs at Mpala Research Centre, Laikipia, the insect communities coexisting with each of the four ant species were characterized, and their response to different vertebrate herbivory. Other ant species inhabiting the tree canopies or the ground were surveyed too. Pitfall trapping was used in sampling terrestrial ants, while beating and mist-blowing were used in collecting arboreal insects. Different sampling methods had varying efficacies, revealing the importance of using several methods. There are at least sixteen ant species in this ecosystem, all occurring on the ground, but only ten species on the trees. Terrestrial ant communities in this ecosystem cannot be used as indicators of grazing pressure for range management. A total of 10,145 individual insects were collected from the tree canopies, comprising of 117 species from seven orders and 25 families, forming a complex community of species interacting at different levels. Symbiotic ant species had a significant effect on insect community structure and composition. Crematogaster sjostedti was associated with a community that was significantly different from the other ant species. There was no significant effect of vertebrate feeding pressure on the canopy insect community, but there was an interaction effect between ant species and treatments. Significant differences between ant species mostly occurred on treatment plots where only cows were allowed to graze. One or more of the ant species may be a keystone species in this ecosystem even though experimental manipulations failed to confirm earlier findings. It was concluded that the one-year period during which experimental manipulations were carried out was not long enough to reflect takeover effects on the insect community. The four symbiotic ant species colonizing S. drepanolobium comprises of two guilds, the hemipteran-tending ants (C. sjostedti and Crematogaster mimosae) and non-tending ants (Crematogaster nigriceps and Tetraponera penzigi). Communities associated with these guilds were found to be significantly different in all four diversity indices. The black cotton ecosystem is species-poor compared to other ecosystem such as forests. The number of insect species that colonizes S. drepanolobium and coexists with acacia-ants forms a large proportion of the invertebrate community. Therefore, this ecosystem should be conserved to safeguard this invertebrate community. This will also give scientists a chance to establish how the various insect species coexist with symbiotic ants on tree canopies.
- Full Text:
- Date Issued: 2007
- Authors: Kuria, Simon Kamande
- Date: 2007
- Subjects: Ants -- Kenya Ants -- Behavior Insect societies -- Kenya Forest canopy ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5758 , http://hdl.handle.net/10962/d1005446
- Description: In the black cotton ecosystem of Laikipia, Kenya, four symbiotic ants coexist at a fine spatial scale on canopies of Senegalia drepanolobium. They exhibit different aggressive behaviours and modify their tree canopies differently. These diverse behaviours were expected to affect the associated canopy arthropod communities. At the Kenya long-term exclosure experiment (KLEE) and its immediate environs at Mpala Research Centre, Laikipia, the insect communities coexisting with each of the four ant species were characterized, and their response to different vertebrate herbivory. Other ant species inhabiting the tree canopies or the ground were surveyed too. Pitfall trapping was used in sampling terrestrial ants, while beating and mist-blowing were used in collecting arboreal insects. Different sampling methods had varying efficacies, revealing the importance of using several methods. There are at least sixteen ant species in this ecosystem, all occurring on the ground, but only ten species on the trees. Terrestrial ant communities in this ecosystem cannot be used as indicators of grazing pressure for range management. A total of 10,145 individual insects were collected from the tree canopies, comprising of 117 species from seven orders and 25 families, forming a complex community of species interacting at different levels. Symbiotic ant species had a significant effect on insect community structure and composition. Crematogaster sjostedti was associated with a community that was significantly different from the other ant species. There was no significant effect of vertebrate feeding pressure on the canopy insect community, but there was an interaction effect between ant species and treatments. Significant differences between ant species mostly occurred on treatment plots where only cows were allowed to graze. One or more of the ant species may be a keystone species in this ecosystem even though experimental manipulations failed to confirm earlier findings. It was concluded that the one-year period during which experimental manipulations were carried out was not long enough to reflect takeover effects on the insect community. The four symbiotic ant species colonizing S. drepanolobium comprises of two guilds, the hemipteran-tending ants (C. sjostedti and Crematogaster mimosae) and non-tending ants (Crematogaster nigriceps and Tetraponera penzigi). Communities associated with these guilds were found to be significantly different in all four diversity indices. The black cotton ecosystem is species-poor compared to other ecosystem such as forests. The number of insect species that colonizes S. drepanolobium and coexists with acacia-ants forms a large proportion of the invertebrate community. Therefore, this ecosystem should be conserved to safeguard this invertebrate community. This will also give scientists a chance to establish how the various insect species coexist with symbiotic ants on tree canopies.
- Full Text:
- Date Issued: 2007
The role of the euthecosome pteropod, limacina retroversa, in the polar frontal zone, Southern Ocean
- Authors: Bernard, Kim Sarah
- Date: 2007
- Subjects: Pteropoda Limacidae Zooplankton -- Antarctic Ocean Copepoda Phytoplankton
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5761 , http://hdl.handle.net/10962/d1005449
- Description: The aim of the present study was to assess the ecological role of the euthecosome pteropod, Limacina retroversa, in particular, and the mesozooplankton community, in general, in the pelagic ecosystem of the Polar Frontal Zone (PFZ), Southern Ocean. Data were collected from four oceanographic surveys to the Indian sector of the PFZ during austral autumn 2000, 2002, 2004 and 2005. Copepods, mainly Calanus simillimus, Oithona similis, Clausocalanus spp. and Ctenocalanus spp., typically dominated total mesozooplankton counts, accounting for, on average, between 75.5 % and 88.1 % (Mean = 77.4 %; SD = 13.4 %) of the total, during the present investigation. Results of the study indicate that L. retroversa may, at times, contribute substantially to total mesozooplankton abundances. During the study, L. retroversa contributed between 0.0 and 30.0 % (Mean = 5.3 %; SD = 7.1 %) to total mesozooplankton numbers. Significant small-scale variability in abundance and size structure of L. retroversa and abundance of copepods was minimal. Inter-annual variability, on the other hand, was significant between some years. Total pteropod numbers were greatest during April 2002 and 2004, while copepods exhibited greatest abundances during April 2004 only. Pearson’s Correlation analysis suggested that L. retroversa abundances were positively correlated to total surface chlorophyll-a (chl-a) concentrations. The significantly lower chl-a concentrations recorded during April 2005 may explain the reduced pteropod numbers observed during that survey. The size class structure of L. retroversa comprised mainly small and mediumsized individuals during all four surveys. This corresponds well with records from the northern hemisphere (sub-Arctic and Arctic waters) where Limacina spp. are reported to exhibit maximum spawning during mid to late-summer. Higher abundances of large individuals only occurred during April 2005, when chl-a concentrations were very low; possibly the result of delayed spawning, due to reduced food availability. Ingestion rates of the four most abundant copepods, determined using the gut fluorescence technique, ranged between 159.32 ng (pigm) ind⁻¹ day⁻¹ and 728.36 ng (pigm) ind⁻¹ day⁻¹ (Mean = 321.01 ng (pigm) ind⁻¹ day⁻¹; SD = 173.91 ng (pigm) ind⁻¹ day). Ingestion rates of L. retroversa were much higher, ranging from an average of 4 28.68 ng (pigm) ind⁻¹ day⁻¹ in April 2002 to 4 196.88 ng (pigm) ind⁻¹day⁻¹in April 2005 (Mean = 4157.36 ng (pigm) ind⁻¹ day⁻¹; SD = 35.37 ng (pigm) ind⁻¹day⁻¹). Average daily grazing rates for the pteropod varied between 0.39 mg (pigm) m⁻² day⁻¹ in April 2005 and 17.69 mg (pigm) m-2 day-1 in April 2004 (Mean = 6.13 mg (pigm) m⁻² day⁻¹; SD = 11.04 mg (pigm) m⁻² day⁻¹); corresponding average daily grazing impacts ranged between 8.4 % and 139.8 % of the phytoplankton standing stock in April 2005 and 2004, respectively (Mean = 48.5 %; SD = 84.5 %). Average daily grazing rates of the four copepods ranged from 4.58 mg (pigm) m⁻² day⁻¹ to 8.77 mg (pigm) m⁻² day⁻¹ -1, during April 2002 and 2004, respectively (Mean = 6.28 mg (pigm) m⁻² day⁻¹; SD = 5.94 mg (pigm) m⁻² day⁻¹). Collectively, the copepods removed an average of between 31.6 % and 89.8 % of the phytoplankton standing stock per day, during April 2002 and 2004, respectively (Mean = 70.8 %; SD = 86.7 %). The daily grazing impact of the copepods accounted for an average of between 40.4 % and 87.8 % of the total zooplankton grazing impact, during April 2004 and 2005, respectively (Mean = 75.0 %; SD = 65.5 %). L. retroversa was responsible for an average of 52.4 % and 59.5 % of the total zooplankton grazing impact, during April 2002 and 2004, respectively. However, during April 2005, when L. retroversa numbers were significantly lower than previous years, the pteropod contributed an average of only 7.5 % to the total zooplankton grazing impact. Thus, during the present investigation,the pteropod was responsible for removing a mean of 48.9 % of the available phytoplankton (SD = 74.9 %). The predation impact of the dominant carnivorous macrozooplankton and micronekton in the PFZ was determined during April 2004 and 2005 using daily ration estimates obtained from the literature. Additionally, gut content analysis was used to determine the contribution of L. retroversa to the diet of the dominant predators. Average predation impact ranged from 1.1 % and 5.7 % of the total mesozooplankton standing stock during April 2004 and 2005, respectively (Mean = 3.8 %; SD = 12.3 %). Chaetognaths and euphausiids dominated total carnivore numbers and made the greatest contributions to total predation impact during both years. Copepods appeared to be the main prey item of the dominant carnivorous macrozooplankton-micronekton in the region. L. retroversa was only detected in the gut contents of the amphipod, Themisto gaudichaudi, but not in either of the chaetognath species (Eukrohnia hamata and Sagitta gazellae) or the myctophid fish (Electrona spp.). The pteropod was found in 19 % of amphipod guts dissected. Pearson’s Correlation analyses showed that the four major predatory zooplankton groups found in the PFZ (chaetognaths, euphausiids, amphipods and myctophid fish) were positively correlated to abundances of L. retroversa, suggesting that the pteropod might be an important prey item for many of the carnivorous macrozooplankton/micronekton in the PFZ. To conclude, L. retroversa may play an important role in the pelagic ecosystem of the PFZ, in austral autumn. However, ocean acidification and calcium carbonate undersaturation (as a result of increased anthropogenic carbon dioxide emissions), that is predicted to occur within the next 50 – 100 years, will most likely have significant implications for the Sub-Antarctic pelagic ecosystem if L. retroversa cannot adapt quickly enough to the changes.
- Full Text:
- Date Issued: 2007
The role of the euthecosome pteropod, limacina retroversa, in the polar frontal zone, Southern Ocean
- Authors: Bernard, Kim Sarah
- Date: 2007
- Subjects: Pteropoda Limacidae Zooplankton -- Antarctic Ocean Copepoda Phytoplankton
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5761 , http://hdl.handle.net/10962/d1005449
- Description: The aim of the present study was to assess the ecological role of the euthecosome pteropod, Limacina retroversa, in particular, and the mesozooplankton community, in general, in the pelagic ecosystem of the Polar Frontal Zone (PFZ), Southern Ocean. Data were collected from four oceanographic surveys to the Indian sector of the PFZ during austral autumn 2000, 2002, 2004 and 2005. Copepods, mainly Calanus simillimus, Oithona similis, Clausocalanus spp. and Ctenocalanus spp., typically dominated total mesozooplankton counts, accounting for, on average, between 75.5 % and 88.1 % (Mean = 77.4 %; SD = 13.4 %) of the total, during the present investigation. Results of the study indicate that L. retroversa may, at times, contribute substantially to total mesozooplankton abundances. During the study, L. retroversa contributed between 0.0 and 30.0 % (Mean = 5.3 %; SD = 7.1 %) to total mesozooplankton numbers. Significant small-scale variability in abundance and size structure of L. retroversa and abundance of copepods was minimal. Inter-annual variability, on the other hand, was significant between some years. Total pteropod numbers were greatest during April 2002 and 2004, while copepods exhibited greatest abundances during April 2004 only. Pearson’s Correlation analysis suggested that L. retroversa abundances were positively correlated to total surface chlorophyll-a (chl-a) concentrations. The significantly lower chl-a concentrations recorded during April 2005 may explain the reduced pteropod numbers observed during that survey. The size class structure of L. retroversa comprised mainly small and mediumsized individuals during all four surveys. This corresponds well with records from the northern hemisphere (sub-Arctic and Arctic waters) where Limacina spp. are reported to exhibit maximum spawning during mid to late-summer. Higher abundances of large individuals only occurred during April 2005, when chl-a concentrations were very low; possibly the result of delayed spawning, due to reduced food availability. Ingestion rates of the four most abundant copepods, determined using the gut fluorescence technique, ranged between 159.32 ng (pigm) ind⁻¹ day⁻¹ and 728.36 ng (pigm) ind⁻¹ day⁻¹ (Mean = 321.01 ng (pigm) ind⁻¹ day⁻¹; SD = 173.91 ng (pigm) ind⁻¹ day). Ingestion rates of L. retroversa were much higher, ranging from an average of 4 28.68 ng (pigm) ind⁻¹ day⁻¹ in April 2002 to 4 196.88 ng (pigm) ind⁻¹day⁻¹in April 2005 (Mean = 4157.36 ng (pigm) ind⁻¹ day⁻¹; SD = 35.37 ng (pigm) ind⁻¹day⁻¹). Average daily grazing rates for the pteropod varied between 0.39 mg (pigm) m⁻² day⁻¹ in April 2005 and 17.69 mg (pigm) m-2 day-1 in April 2004 (Mean = 6.13 mg (pigm) m⁻² day⁻¹; SD = 11.04 mg (pigm) m⁻² day⁻¹); corresponding average daily grazing impacts ranged between 8.4 % and 139.8 % of the phytoplankton standing stock in April 2005 and 2004, respectively (Mean = 48.5 %; SD = 84.5 %). Average daily grazing rates of the four copepods ranged from 4.58 mg (pigm) m⁻² day⁻¹ to 8.77 mg (pigm) m⁻² day⁻¹ -1, during April 2002 and 2004, respectively (Mean = 6.28 mg (pigm) m⁻² day⁻¹; SD = 5.94 mg (pigm) m⁻² day⁻¹). Collectively, the copepods removed an average of between 31.6 % and 89.8 % of the phytoplankton standing stock per day, during April 2002 and 2004, respectively (Mean = 70.8 %; SD = 86.7 %). The daily grazing impact of the copepods accounted for an average of between 40.4 % and 87.8 % of the total zooplankton grazing impact, during April 2004 and 2005, respectively (Mean = 75.0 %; SD = 65.5 %). L. retroversa was responsible for an average of 52.4 % and 59.5 % of the total zooplankton grazing impact, during April 2002 and 2004, respectively. However, during April 2005, when L. retroversa numbers were significantly lower than previous years, the pteropod contributed an average of only 7.5 % to the total zooplankton grazing impact. Thus, during the present investigation,the pteropod was responsible for removing a mean of 48.9 % of the available phytoplankton (SD = 74.9 %). The predation impact of the dominant carnivorous macrozooplankton and micronekton in the PFZ was determined during April 2004 and 2005 using daily ration estimates obtained from the literature. Additionally, gut content analysis was used to determine the contribution of L. retroversa to the diet of the dominant predators. Average predation impact ranged from 1.1 % and 5.7 % of the total mesozooplankton standing stock during April 2004 and 2005, respectively (Mean = 3.8 %; SD = 12.3 %). Chaetognaths and euphausiids dominated total carnivore numbers and made the greatest contributions to total predation impact during both years. Copepods appeared to be the main prey item of the dominant carnivorous macrozooplankton-micronekton in the region. L. retroversa was only detected in the gut contents of the amphipod, Themisto gaudichaudi, but not in either of the chaetognath species (Eukrohnia hamata and Sagitta gazellae) or the myctophid fish (Electrona spp.). The pteropod was found in 19 % of amphipod guts dissected. Pearson’s Correlation analyses showed that the four major predatory zooplankton groups found in the PFZ (chaetognaths, euphausiids, amphipods and myctophid fish) were positively correlated to abundances of L. retroversa, suggesting that the pteropod might be an important prey item for many of the carnivorous macrozooplankton/micronekton in the PFZ. To conclude, L. retroversa may play an important role in the pelagic ecosystem of the PFZ, in austral autumn. However, ocean acidification and calcium carbonate undersaturation (as a result of increased anthropogenic carbon dioxide emissions), that is predicted to occur within the next 50 – 100 years, will most likely have significant implications for the Sub-Antarctic pelagic ecosystem if L. retroversa cannot adapt quickly enough to the changes.
- Full Text:
- Date Issued: 2007
Towards a theory of choral conducting gestures
- Oosthuizen, Benjamin William
- Authors: Oosthuizen, Benjamin William
- Date: 2007
- Subjects: Choral conducting
- Language: English
- Type: Thesis , Doctoral , DMus
- Identifier: vital:8505 , http://hdl.handle.net/10948/589 , Choral conducting
- Description: It is an oversimplification to look only at the manner in which a two-dimensional drawing suggests a three-dimensional movement in order to study choral conducting gestures. It must be recognised that there is a myriad of tacit aspects of knowledge surrounding conducting gestures. These aspects of tacit knowledge might be the reason why the teaching of conducting is done mostly in a continuous practicum, where the apprentice learns from the master, because in the practical situation the novice learns not only explicit knowledge, but also tacit knowledge. On the other hand, it is vital that the process of categorising and theorising about gestures continues in order to at least gain a better explicit knowledge of the process. In doing so, a theoretical knowledge base will strengthen the body of knowledge. This explicit knowledge should contain information with regard to the anatomy of the conductor, a basic understanding of a balanced posture, bilateral symmetry and vertical alignment, and a basic knowledge which will help to understand which main muscle groups are responsible for which basic movements involving gestures. The study of gestures from a theoretical point of view is barely more than five decades old. The demands which 20th and 21st century composers make on conductors question the traditional approaches of the functions of the hands. It has become essential for a conductor to develop greater skill of ambidexterity in order to cope with these demands. Despite the notion by some authors that choral conducting gestures employ standard gestures, it has been shown in this study that this is simply not the case. An overview of the work of authors in the field of conducting gestures was presented through a literature study. Concepts and their definitions have been selected and explained through the answering of research questions. Definitions of parameters and functionality of gestures were clarified to decide which gestures were the most appropriate in certain circumstances. This theory aims to be both descriptive and normative. It is descriptive in the sense that the concepts and issues and relationships around the characteristic aspects of gestures are indicated. It is normative in terms of the suggestions offered with regard to issues pertaining to gestures. This thesis sets out to contribute to the formulation of theoretical aspects of choral conducting gestures in an effort to codify and structure knowledge which is often stored in composers minds and experience, in an effort to pass down this knowledge to other apprentices in the field.
- Full Text:
- Date Issued: 2007
- Authors: Oosthuizen, Benjamin William
- Date: 2007
- Subjects: Choral conducting
- Language: English
- Type: Thesis , Doctoral , DMus
- Identifier: vital:8505 , http://hdl.handle.net/10948/589 , Choral conducting
- Description: It is an oversimplification to look only at the manner in which a two-dimensional drawing suggests a three-dimensional movement in order to study choral conducting gestures. It must be recognised that there is a myriad of tacit aspects of knowledge surrounding conducting gestures. These aspects of tacit knowledge might be the reason why the teaching of conducting is done mostly in a continuous practicum, where the apprentice learns from the master, because in the practical situation the novice learns not only explicit knowledge, but also tacit knowledge. On the other hand, it is vital that the process of categorising and theorising about gestures continues in order to at least gain a better explicit knowledge of the process. In doing so, a theoretical knowledge base will strengthen the body of knowledge. This explicit knowledge should contain information with regard to the anatomy of the conductor, a basic understanding of a balanced posture, bilateral symmetry and vertical alignment, and a basic knowledge which will help to understand which main muscle groups are responsible for which basic movements involving gestures. The study of gestures from a theoretical point of view is barely more than five decades old. The demands which 20th and 21st century composers make on conductors question the traditional approaches of the functions of the hands. It has become essential for a conductor to develop greater skill of ambidexterity in order to cope with these demands. Despite the notion by some authors that choral conducting gestures employ standard gestures, it has been shown in this study that this is simply not the case. An overview of the work of authors in the field of conducting gestures was presented through a literature study. Concepts and their definitions have been selected and explained through the answering of research questions. Definitions of parameters and functionality of gestures were clarified to decide which gestures were the most appropriate in certain circumstances. This theory aims to be both descriptive and normative. It is descriptive in the sense that the concepts and issues and relationships around the characteristic aspects of gestures are indicated. It is normative in terms of the suggestions offered with regard to issues pertaining to gestures. This thesis sets out to contribute to the formulation of theoretical aspects of choral conducting gestures in an effort to codify and structure knowledge which is often stored in composers minds and experience, in an effort to pass down this knowledge to other apprentices in the field.
- Full Text:
- Date Issued: 2007
Towards a transnational feminist aesthetic: an analysis of selected prose writing by women of the South Asian diaspora
- Authors: Naidu, Samantha
- Date: 2007
- Subjects: South Asian literature -- Women authors , Women and literature -- Asia , English prose literature -- Women authors -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2307 , http://hdl.handle.net/10962/d1012941 , https://orcid.org/0000-0001-9456-8657
- Description: This thesis argues that women writers of the South Asian diaspora are inscribing a literary aesthetic which is recognisably feminist. In recent decades women of the South Asian diaspora have risen to the forefront of the global literary and publishing arena, winning acclaim for their endeavours. The scope of this literature is wide, in terms of themes, styles, genres, and geographic location. Prose works range from grave novelistic explorations of female subjectivity to short story collections intent on capturing historical injustices and the experiences of migration. The thesis demonstrates, through close readings and comparative frameworks, that an overarching pattern of common aesthetic elements is deployed in this literature. This deployment is regarded as a transnational feminist practice.
- Full Text:
- Date Issued: 2007
- Authors: Naidu, Samantha
- Date: 2007
- Subjects: South Asian literature -- Women authors , Women and literature -- Asia , English prose literature -- Women authors -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2307 , http://hdl.handle.net/10962/d1012941 , https://orcid.org/0000-0001-9456-8657
- Description: This thesis argues that women writers of the South Asian diaspora are inscribing a literary aesthetic which is recognisably feminist. In recent decades women of the South Asian diaspora have risen to the forefront of the global literary and publishing arena, winning acclaim for their endeavours. The scope of this literature is wide, in terms of themes, styles, genres, and geographic location. Prose works range from grave novelistic explorations of female subjectivity to short story collections intent on capturing historical injustices and the experiences of migration. The thesis demonstrates, through close readings and comparative frameworks, that an overarching pattern of common aesthetic elements is deployed in this literature. This deployment is regarded as a transnational feminist practice.
- Full Text:
- Date Issued: 2007
Towards knowing through doing : improving the societal relevance of systematic conservation assessments
- Authors: Knight, Andrew Thomas
- Date: 2007
- Subjects: Conservation of natural resources -- Planning , Nature conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10598 , http://hdl.handle.net/10948/711 , Conservation of natural resources -- Planning , Nature conservation -- South Africa
- Description: Systematic conservation assessments are spatially-explicit techniques for prioritising areas for the implementation of conservation action. There has been considerable reference in the peer-reviewed literature as to the usefulness of these tools, which appear to be primarily used by academics for theoretical research. A literature review and author survey reveals the peer-reviewed literature is largely theoretical, although conservation action results more frequently than reported. The effectiveness of these interventions is generally described as only ‘fairly effective’. This general trend, coupled with previous personal failures in translating systematic conservation assessments into effective conservation action triggered an explicit process of social learning implemented as action research. It examined the workings of the Subtropical Thicket Ecosystem Planning (STEP) project, which included development of a systematic conservation assessment. Systematic conservations assessments simply provide information on where action should be implemented, and so are only useful if situated within broader operational models for conservation planning. Most operational models presented in the peer-reviewed literature are primarily focused upon the testing ecological data, not upon the delivery of conservation action. A new operational model for conservation planning is presented which more accurately reflects the ‘real-world’ process of conservation planning. An implementation strategy is an essential complement to a systematic conservation assessment. It describes how specific, explicitly-stated goals will be achieved, who is accountable for undertaking these activities, and the resources required. As the Implementation Specialist for the STEP Project, I co-lead the collaborative development of an implementation strategy with stakeholders that aimed to mobilise resources towards achieving common goals. Whilst the development and initial uptake of the strategy was good, subsequent implementation has flounder. The reasons for this are explored. The ultimate pragmatic goal of a conservation planning process is the establishment of effective social learning institutions. These develop common visions, mobilise collective action, and adaptively learn and refine their conservation activities. Thicket Forum is one xi such institution established through the STEP Project. My involvement with Thicket Forum since 2004 in implementing an adaptive learning approach facilitates collaboration between land managers, government and research organisations. Systematic conservation assessments evolved in response to the ad hoc way in which protected areas were implemented, leaving unrepresentative, biased protected area networks. Most research is theoretical and without an intimate understanding of the social-ecological system of a planning region, notably opportunities and constraints for implementing conservation action. Highlighting the importance of an approach which is flexible, not only in space, but in time, which can capitalise upon implementation opportunities, is important for stemming the myth that opportunism is the nemesis of systematic conservation assessments. To this end, conservation planners have been slow to include factors influencing effective implementation in systematic conservation assessments. Many studies which identify candidate protected area networks, first, fail to identify the specific instrument(s) to be applied, and second, assume all intact land is available. Having mapped the willingness of land managers in the Albany District, South Africa, to sell their land, it is demonstrated the majority of targets fail to be achieved because land managers will not sell. Knowing this, the current focus of gathering ever-more ecological data is misplaced. Human, social and economic factors influence target achievement, efficiency and spatial configuration of priority areas. Selecting important areas for conservation, particularly at the local-scale, requires the mapping of factors which define opportunities for conservation. Land manager willingness to collaborate and participate, entrepreneurial orientation, conservation knowledge, social capital, and local champions were applied using a method of hierarchical clustering to identify land managers who represent conservation opportunities for private land conservation initiatives.
- Full Text:
- Date Issued: 2007
- Authors: Knight, Andrew Thomas
- Date: 2007
- Subjects: Conservation of natural resources -- Planning , Nature conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10598 , http://hdl.handle.net/10948/711 , Conservation of natural resources -- Planning , Nature conservation -- South Africa
- Description: Systematic conservation assessments are spatially-explicit techniques for prioritising areas for the implementation of conservation action. There has been considerable reference in the peer-reviewed literature as to the usefulness of these tools, which appear to be primarily used by academics for theoretical research. A literature review and author survey reveals the peer-reviewed literature is largely theoretical, although conservation action results more frequently than reported. The effectiveness of these interventions is generally described as only ‘fairly effective’. This general trend, coupled with previous personal failures in translating systematic conservation assessments into effective conservation action triggered an explicit process of social learning implemented as action research. It examined the workings of the Subtropical Thicket Ecosystem Planning (STEP) project, which included development of a systematic conservation assessment. Systematic conservations assessments simply provide information on where action should be implemented, and so are only useful if situated within broader operational models for conservation planning. Most operational models presented in the peer-reviewed literature are primarily focused upon the testing ecological data, not upon the delivery of conservation action. A new operational model for conservation planning is presented which more accurately reflects the ‘real-world’ process of conservation planning. An implementation strategy is an essential complement to a systematic conservation assessment. It describes how specific, explicitly-stated goals will be achieved, who is accountable for undertaking these activities, and the resources required. As the Implementation Specialist for the STEP Project, I co-lead the collaborative development of an implementation strategy with stakeholders that aimed to mobilise resources towards achieving common goals. Whilst the development and initial uptake of the strategy was good, subsequent implementation has flounder. The reasons for this are explored. The ultimate pragmatic goal of a conservation planning process is the establishment of effective social learning institutions. These develop common visions, mobilise collective action, and adaptively learn and refine their conservation activities. Thicket Forum is one xi such institution established through the STEP Project. My involvement with Thicket Forum since 2004 in implementing an adaptive learning approach facilitates collaboration between land managers, government and research organisations. Systematic conservation assessments evolved in response to the ad hoc way in which protected areas were implemented, leaving unrepresentative, biased protected area networks. Most research is theoretical and without an intimate understanding of the social-ecological system of a planning region, notably opportunities and constraints for implementing conservation action. Highlighting the importance of an approach which is flexible, not only in space, but in time, which can capitalise upon implementation opportunities, is important for stemming the myth that opportunism is the nemesis of systematic conservation assessments. To this end, conservation planners have been slow to include factors influencing effective implementation in systematic conservation assessments. Many studies which identify candidate protected area networks, first, fail to identify the specific instrument(s) to be applied, and second, assume all intact land is available. Having mapped the willingness of land managers in the Albany District, South Africa, to sell their land, it is demonstrated the majority of targets fail to be achieved because land managers will not sell. Knowing this, the current focus of gathering ever-more ecological data is misplaced. Human, social and economic factors influence target achievement, efficiency and spatial configuration of priority areas. Selecting important areas for conservation, particularly at the local-scale, requires the mapping of factors which define opportunities for conservation. Land manager willingness to collaborate and participate, entrepreneurial orientation, conservation knowledge, social capital, and local champions were applied using a method of hierarchical clustering to identify land managers who represent conservation opportunities for private land conservation initiatives.
- Full Text:
- Date Issued: 2007
Transcending state-centrism: new regionalism and the future of Southern African regional integration
- Authors: Blaauw, Lesley
- Date: 2007
- Subjects: Southern African Development Community Southern African Customs Union Southern African Development Coordination Conference Regionalism -- Africa, Southern Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2761 , http://hdl.handle.net/10962/d1002971
- Description: This dissertation argues that in the 1990s and beyond, the character and functions of regions and regionalism have experienced a major transformation. This requires a reconceptualisation of regions and regionalism that transcends state-centrism. The argument here is that the definition of regions and regionalism needs to recognise that other actors also participate in the construction of regions and the practise of regionalism. Up to now, however, theories of integration incompletely deal with outcomes appropriate to developing countries, states and regions. In the context where people remain vulnerable to top-down forms of regionalism driven by the forces of globalisation, this calls for a new approach in the analytical study of regionalism in a transnational context. The contention is that new regionalism, and its variant, developmental regionalism pay attention to the role those organised civil society actors and those marginalised by both globalisation and regionalisation play in promoting regionalism in a transnational context. Historically, state-centric regionalism in southern Africa was not aimed at achieving developmental objectives. In the case of SACU, the argument is that South Africa used its economic strength in a hegemonial way. To counter-act apartheid South Africa’s economic hegemony, SADCC was formed. SADCC achieved limited success in the fields of infrastructural development and in attracting donor aid. The end of the Cold War and the downfall of apartheid compelled these organisations to recast their objectives and purpose. For SACU this meant changing from an organisation dominated by South Africa to a fully-fledged inter-state one. Disconcertedly, however, about the reforms undertook by SACU, is that the disposition of member states remain important in determining the content and scope of regionalism. SADC, on the other hand, has also not sufficiently reform itself to achieve the ambitious goals it set-out for itself. Moreover, while SADC has since its inception in 1992 set-out to involve non-state actors in its regional integration efforts, limited institutional reform in 2000 and beyond, and elites at the forefront of institutional restructuring make it difficult for non-state actors to contribute to sustainable regional integration. In conclusion, this dissertation maintains that sustainable regionalist orders are best built by recognising that beyond the geometry of state-sovereignty, civil society organisations with a regional focus and the ordinary people of the region also contribute to regioness and as such to the re-conceptualisation of regional community in southern Africa.
- Full Text:
- Date Issued: 2007
Transcending state-centrism: new regionalism and the future of Southern African regional integration
- Authors: Blaauw, Lesley
- Date: 2007
- Subjects: Southern African Development Community Southern African Customs Union Southern African Development Coordination Conference Regionalism -- Africa, Southern Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2761 , http://hdl.handle.net/10962/d1002971
- Description: This dissertation argues that in the 1990s and beyond, the character and functions of regions and regionalism have experienced a major transformation. This requires a reconceptualisation of regions and regionalism that transcends state-centrism. The argument here is that the definition of regions and regionalism needs to recognise that other actors also participate in the construction of regions and the practise of regionalism. Up to now, however, theories of integration incompletely deal with outcomes appropriate to developing countries, states and regions. In the context where people remain vulnerable to top-down forms of regionalism driven by the forces of globalisation, this calls for a new approach in the analytical study of regionalism in a transnational context. The contention is that new regionalism, and its variant, developmental regionalism pay attention to the role those organised civil society actors and those marginalised by both globalisation and regionalisation play in promoting regionalism in a transnational context. Historically, state-centric regionalism in southern Africa was not aimed at achieving developmental objectives. In the case of SACU, the argument is that South Africa used its economic strength in a hegemonial way. To counter-act apartheid South Africa’s economic hegemony, SADCC was formed. SADCC achieved limited success in the fields of infrastructural development and in attracting donor aid. The end of the Cold War and the downfall of apartheid compelled these organisations to recast their objectives and purpose. For SACU this meant changing from an organisation dominated by South Africa to a fully-fledged inter-state one. Disconcertedly, however, about the reforms undertook by SACU, is that the disposition of member states remain important in determining the content and scope of regionalism. SADC, on the other hand, has also not sufficiently reform itself to achieve the ambitious goals it set-out for itself. Moreover, while SADC has since its inception in 1992 set-out to involve non-state actors in its regional integration efforts, limited institutional reform in 2000 and beyond, and elites at the forefront of institutional restructuring make it difficult for non-state actors to contribute to sustainable regional integration. In conclusion, this dissertation maintains that sustainable regionalist orders are best built by recognising that beyond the geometry of state-sovereignty, civil society organisations with a regional focus and the ordinary people of the region also contribute to regioness and as such to the re-conceptualisation of regional community in southern Africa.
- Full Text:
- Date Issued: 2007
Treatment of wine distillery wastewaters by high rate anaerobic digestion and submerged membrane systems
- Authors: Melamane, Xolisa Lorraine
- Date: 2007
- Subjects: Wine and wine making -- Waste disposal Sewage -- Purification -- Anaerobic treatment Membrane reactors Bioreactors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3963 , http://hdl.handle.net/10962/d1004022
- Description: Experiences in treating wine distillery wastewaters (WDWs) contribute to the field of oenology as many oenologists are concerned with the selection, efficiency and economy of their wastewaters. Wine distillery wastewaters are strongly acidic, have high chemical oxygen demand (COD), high polyphenol content and are highly variable. Primary attention was focussed on sustainable biological treatment of raw wine distillery wastewater (RWDW) and fungally pre-treated wine distillery wastewater (FTWDW) by energy-efficient high rate anaerobic digestion (AD). This study also explored the development of a novel dual-stage anaerobic digestion ultrafiltration (ADUF) process, using a ceramic submerged membrane bioreactor (SMBR) in the treatment of both RWDW and FTWDW. The first stage was for the selection of microorganisms that were able to treat the toxic pollutants from WDWs. It was operated at a high feed-to-microorganism ratio. The second stage, a secondary digester, was operated like a typical membrane bioreactor at a low feed-to-microorganism ratio to sustain a stable efficient population for a long period. The characteristics of RWDW were as follows: pH 3.83, 15 000 mg/l soluble COD (CODs) and 5229 mg/l of phenols. After pre-treatment of RWDW with Trametes pubescens, starting parameters for FTWDW were as follows: pH 6.7, 7000 mg/l soluble COD (CODS) and 1440 mg/l of phenols. During operation of a high rate anaerobic digester for RWDW treatment, K2HPO4 was required for buffering the digester. Volatile fatty acid concentrations were <300 mg/l throughout the study, indicating degradation of organic acids present. Mean CODS removal efficiency for the 130 day study was 87 %, while the mean polyphenol removal efficiency was 85 %. Addition of 50 mg/l Fe3+ increased the removal efficiencies of CODS to 97 % and of polyphenols to 99 %. High removal efficiencies of CODS and polyphenols were attributed to the addition of macronutrients and micronutrients that caused pH stability and stimulated microbial activity. The CODS removal efficiency of high rate anaerobic digestion of FTWDW reached 99.5%. During FTWDW digestion, pH buffering was achieved using K2HPO4. A combination of a SMBR and a secondary digester was tested for the treatment of RWDW and FTWDW during a 30 day study. Results for RWDW showed that pH buffering was achieved by dosing the feed stream with CaCO3 and K2HPO4. Buffering proved to be significant for optimum performance of the system in removal of soluble CODS, and volatile fatty acids (VFAs). Different batches of RWDW used for feeding the reactor had variable compositions with respect to concentrations of nitrates, ammonium and total phenolic compounds. Ammonium accumulated in the secondary digester after 14 days of system operation, indicated the time required for the establishment of anaerobic conditions in the system. Dosing of the SMBR treating FTWDW with CaCO3 and K2HPO4 buffered the pH; iii this proved significant for optimum performance of the system in removal of CODS. The system eliminated an average of 86 (± 4) % of CODS present in the FTWDW. The residual CODS levels in the effluent were approximately 400 mg/l, significantly lower than the concentrations observed when treating RWDW, indicating that fungal pre-treatment might have provided additional nutrients for removal of recalcitrant components of the wastewater. The resulting effluent was rich in nitrates and phosphates and might be used as a fertiliser. Alternatively, a membrane process, such as reverse osmosis (RO) or nanofiltration (NF) could be applied to raise the water quality to meet the levels required for reuse. Biomass samples were obtained from the four treatment systems and population shifts characterization using phospholipids fatty acids (PLFA) and 16S rRNA analysis to provide an indication of limitations within the microbial population. The values of the concentrations of the individual PLFAs detected in the samples indicated that ten bacterial species were present, with the GC content of the 16S rRNA increasing from 1 to 10. Analysis of denaturing gradient gel electrophoresis DGGE data indicated that the composition of the archeal community changed the consortia used for both RWDW and FTWDW treatment. Changes in band intensities indicated the presence of different components of the archeal communities. The results were not conclusive in terms of species identity as cloning, sequencing and phylogenetic analyses were not performed, but they did indicate microbial population shifts and species diversity for high rate anaerobic digestion. The results also confirmed prevalence of relatively few species during operation of SMBRs for treatment of RWDW and FTWDW, which suggested that the microorganisms that survived were either tolerant of toxic components of RWDW and FTWDW or they were able to remove polyphenols.
- Full Text:
- Date Issued: 2007
- Authors: Melamane, Xolisa Lorraine
- Date: 2007
- Subjects: Wine and wine making -- Waste disposal Sewage -- Purification -- Anaerobic treatment Membrane reactors Bioreactors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3963 , http://hdl.handle.net/10962/d1004022
- Description: Experiences in treating wine distillery wastewaters (WDWs) contribute to the field of oenology as many oenologists are concerned with the selection, efficiency and economy of their wastewaters. Wine distillery wastewaters are strongly acidic, have high chemical oxygen demand (COD), high polyphenol content and are highly variable. Primary attention was focussed on sustainable biological treatment of raw wine distillery wastewater (RWDW) and fungally pre-treated wine distillery wastewater (FTWDW) by energy-efficient high rate anaerobic digestion (AD). This study also explored the development of a novel dual-stage anaerobic digestion ultrafiltration (ADUF) process, using a ceramic submerged membrane bioreactor (SMBR) in the treatment of both RWDW and FTWDW. The first stage was for the selection of microorganisms that were able to treat the toxic pollutants from WDWs. It was operated at a high feed-to-microorganism ratio. The second stage, a secondary digester, was operated like a typical membrane bioreactor at a low feed-to-microorganism ratio to sustain a stable efficient population for a long period. The characteristics of RWDW were as follows: pH 3.83, 15 000 mg/l soluble COD (CODs) and 5229 mg/l of phenols. After pre-treatment of RWDW with Trametes pubescens, starting parameters for FTWDW were as follows: pH 6.7, 7000 mg/l soluble COD (CODS) and 1440 mg/l of phenols. During operation of a high rate anaerobic digester for RWDW treatment, K2HPO4 was required for buffering the digester. Volatile fatty acid concentrations were <300 mg/l throughout the study, indicating degradation of organic acids present. Mean CODS removal efficiency for the 130 day study was 87 %, while the mean polyphenol removal efficiency was 85 %. Addition of 50 mg/l Fe3+ increased the removal efficiencies of CODS to 97 % and of polyphenols to 99 %. High removal efficiencies of CODS and polyphenols were attributed to the addition of macronutrients and micronutrients that caused pH stability and stimulated microbial activity. The CODS removal efficiency of high rate anaerobic digestion of FTWDW reached 99.5%. During FTWDW digestion, pH buffering was achieved using K2HPO4. A combination of a SMBR and a secondary digester was tested for the treatment of RWDW and FTWDW during a 30 day study. Results for RWDW showed that pH buffering was achieved by dosing the feed stream with CaCO3 and K2HPO4. Buffering proved to be significant for optimum performance of the system in removal of soluble CODS, and volatile fatty acids (VFAs). Different batches of RWDW used for feeding the reactor had variable compositions with respect to concentrations of nitrates, ammonium and total phenolic compounds. Ammonium accumulated in the secondary digester after 14 days of system operation, indicated the time required for the establishment of anaerobic conditions in the system. Dosing of the SMBR treating FTWDW with CaCO3 and K2HPO4 buffered the pH; iii this proved significant for optimum performance of the system in removal of CODS. The system eliminated an average of 86 (± 4) % of CODS present in the FTWDW. The residual CODS levels in the effluent were approximately 400 mg/l, significantly lower than the concentrations observed when treating RWDW, indicating that fungal pre-treatment might have provided additional nutrients for removal of recalcitrant components of the wastewater. The resulting effluent was rich in nitrates and phosphates and might be used as a fertiliser. Alternatively, a membrane process, such as reverse osmosis (RO) or nanofiltration (NF) could be applied to raise the water quality to meet the levels required for reuse. Biomass samples were obtained from the four treatment systems and population shifts characterization using phospholipids fatty acids (PLFA) and 16S rRNA analysis to provide an indication of limitations within the microbial population. The values of the concentrations of the individual PLFAs detected in the samples indicated that ten bacterial species were present, with the GC content of the 16S rRNA increasing from 1 to 10. Analysis of denaturing gradient gel electrophoresis DGGE data indicated that the composition of the archeal community changed the consortia used for both RWDW and FTWDW treatment. Changes in band intensities indicated the presence of different components of the archeal communities. The results were not conclusive in terms of species identity as cloning, sequencing and phylogenetic analyses were not performed, but they did indicate microbial population shifts and species diversity for high rate anaerobic digestion. The results also confirmed prevalence of relatively few species during operation of SMBRs for treatment of RWDW and FTWDW, which suggested that the microorganisms that survived were either tolerant of toxic components of RWDW and FTWDW or they were able to remove polyphenols.
- Full Text:
- Date Issued: 2007
Trends in fish community structure and recruitment in a temporarily open/closed South African estuary
- Authors: James, Nicola Caroline
- Date: 2007
- Subjects: Fish communities -- South Africa -- Eastern Cape Marine fishes -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5332 , http://hdl.handle.net/10962/d1005178
- Description: Long-term interannual changes in richness, abundance, diversity and structure of the fish community in the temporarily open/closed East Kleinemonde Estuary, Eastern Cape, are described and the recruitment success of two estuary-dependent marine species assessed. In addition, laboratory experiments were conducted to assess the possible role of olfaction in the recruitment process of an estuary-dependent marine fish species. Multivariate analyses of the annual marine fish communites identified two distinct groups with more species recorded during years that succeeded spring (September to November) mouth opening events than in years following no mouth opening events in spring. Interannual community stability (IMD) and seriation (IMS) also increased from the ‘other’ to the ‘spring’ years. These results highlight the importance of the timing of mouth opening to the marine fish community in a temporarily open/closed estuary. This study also made use of long-term records of daily mouth state and linked them to the recruitment of distinct year-class cohorts in two spardis with contrasting lifehistory characteristics. Lithognathus lithognathus only recruited into the estuary in years when the mouth opened between late August and January. This was linked to the limited spawning season of this species and its inability to enter closed estuaries via wave overwash events. In contrast, recruitment by Rhabdosargus holubi juveniles appeared to be uninterrupted and was not determined by the seasonality of mouth opening. This species dominates the marine-spawning component of the East Kleinemonde Estuary and its success is attributed to an extended spawning season and its ability to recruit into estuaries during both overwash and open mouth conditions. Attraction of postflexion Rhabdosargus holubi larvae to estuary, surf zone and river water was also measured using a rectangular choice chamber. In two sets of experiments, conducted during peak recruitment periods, larvae from both the surf zone and estuary mouth region selected estuary water with a significantly higher frequency than sea water. Larvae collected in the mouth region showed a stronger preference for river water than those collected in the surf zone, thus suggesting that these fish are more attracted to freshwater influenced nursery areas once they have entered the estuary than those in the surf zone. Larvae collected in the marine environment also selected surf zone water with significantly higher frequencies than estuary water or offshore sea water, thus confirming the importance of the surf zone as an interim nursery area for postflexion R. holubi.
- Full Text:
- Date Issued: 2007
- Authors: James, Nicola Caroline
- Date: 2007
- Subjects: Fish communities -- South Africa -- Eastern Cape Marine fishes -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5332 , http://hdl.handle.net/10962/d1005178
- Description: Long-term interannual changes in richness, abundance, diversity and structure of the fish community in the temporarily open/closed East Kleinemonde Estuary, Eastern Cape, are described and the recruitment success of two estuary-dependent marine species assessed. In addition, laboratory experiments were conducted to assess the possible role of olfaction in the recruitment process of an estuary-dependent marine fish species. Multivariate analyses of the annual marine fish communites identified two distinct groups with more species recorded during years that succeeded spring (September to November) mouth opening events than in years following no mouth opening events in spring. Interannual community stability (IMD) and seriation (IMS) also increased from the ‘other’ to the ‘spring’ years. These results highlight the importance of the timing of mouth opening to the marine fish community in a temporarily open/closed estuary. This study also made use of long-term records of daily mouth state and linked them to the recruitment of distinct year-class cohorts in two spardis with contrasting lifehistory characteristics. Lithognathus lithognathus only recruited into the estuary in years when the mouth opened between late August and January. This was linked to the limited spawning season of this species and its inability to enter closed estuaries via wave overwash events. In contrast, recruitment by Rhabdosargus holubi juveniles appeared to be uninterrupted and was not determined by the seasonality of mouth opening. This species dominates the marine-spawning component of the East Kleinemonde Estuary and its success is attributed to an extended spawning season and its ability to recruit into estuaries during both overwash and open mouth conditions. Attraction of postflexion Rhabdosargus holubi larvae to estuary, surf zone and river water was also measured using a rectangular choice chamber. In two sets of experiments, conducted during peak recruitment periods, larvae from both the surf zone and estuary mouth region selected estuary water with a significantly higher frequency than sea water. Larvae collected in the mouth region showed a stronger preference for river water than those collected in the surf zone, thus suggesting that these fish are more attracted to freshwater influenced nursery areas once they have entered the estuary than those in the surf zone. Larvae collected in the marine environment also selected surf zone water with significantly higher frequencies than estuary water or offshore sea water, thus confirming the importance of the surf zone as an interim nursery area for postflexion R. holubi.
- Full Text:
- Date Issued: 2007