Surface characteristics of rock glaciers in the Jutulsessen, Dronning Maud Land, Antarctica
- Rudolph, Elizabeth Magdalena
- Authors: Rudolph, Elizabeth Magdalena
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2667 , vital:20314
- Description: Rock glaciers are landforms that present downslope movement of debris under the influence of ice and gravity. These landforms can be used as paleo-climate indicators as well as proxies for climate change. Rock glaciers have been investigated in a variety of climates and landscapes, however continental Antarctica, Dronning Maud Land specifically, remains understudied. This thesis aimed to investigate and classify five rock glaciers observed in the Jutulsessen, Dronning Maud Land. The surface characteristics and geomorphology were assessed and used as generic classifiers. Size, shape and landscape association was established by field surveying and GIS, whilst sediment and clast characteristics were determined from sampling. A surface temperature profile was created from short-term high frequency temperature measurements. All of the rock glaciers exhibit either undulating surfaces or patterned ground, or both, which suggests active-layer related processes. Sediment particle size analysis is inconclusive. The 137Cs-content and fabric analysis suggest movement regimes similar to other rock glaciers with higher activity at the head, and variable movement directions at the toe. Relative “activeness” is inferred from morphology: Grjotlia, Grjotøyra and Vassdalen were classified as lobate, spatulate and tongue-shaped respectively with Grjotlia the most stable. A new morphological classification of ‘crown-shaped’ is suggested for Brugdedalen and Jutuldalen, and they also appear most active. The control of local climate on rock glacier mechanics is emphasised by the findings, and thus climatic interpolation from a single weather stations is not useful. Increased spatial and temporal coverage of sediment profiles, surface topography and active-layer characteristics could be used to elucidate the processes and controls of these landforms in the Antarctic.
- Full Text:
- Date Issued: 2016
- Authors: Rudolph, Elizabeth Magdalena
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2667 , vital:20314
- Description: Rock glaciers are landforms that present downslope movement of debris under the influence of ice and gravity. These landforms can be used as paleo-climate indicators as well as proxies for climate change. Rock glaciers have been investigated in a variety of climates and landscapes, however continental Antarctica, Dronning Maud Land specifically, remains understudied. This thesis aimed to investigate and classify five rock glaciers observed in the Jutulsessen, Dronning Maud Land. The surface characteristics and geomorphology were assessed and used as generic classifiers. Size, shape and landscape association was established by field surveying and GIS, whilst sediment and clast characteristics were determined from sampling. A surface temperature profile was created from short-term high frequency temperature measurements. All of the rock glaciers exhibit either undulating surfaces or patterned ground, or both, which suggests active-layer related processes. Sediment particle size analysis is inconclusive. The 137Cs-content and fabric analysis suggest movement regimes similar to other rock glaciers with higher activity at the head, and variable movement directions at the toe. Relative “activeness” is inferred from morphology: Grjotlia, Grjotøyra and Vassdalen were classified as lobate, spatulate and tongue-shaped respectively with Grjotlia the most stable. A new morphological classification of ‘crown-shaped’ is suggested for Brugdedalen and Jutuldalen, and they also appear most active. The control of local climate on rock glacier mechanics is emphasised by the findings, and thus climatic interpolation from a single weather stations is not useful. Increased spatial and temporal coverage of sediment profiles, surface topography and active-layer characteristics could be used to elucidate the processes and controls of these landforms in the Antarctic.
- Full Text:
- Date Issued: 2016
The efficacy of a community based eccentric hamstring strengthening program in peri-urban Black South African soccer players
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016
An investigation on the effect of Russian wheat aphid (Diuraphis noxia Kurdjumov) population growth and feeding damage on selected barley (Hordeum vulgare L.) cultivars under ambient and elevated CO2
- Authors: Sacranie, Sattar Farouk
- Date: 2016
- Subjects: Russian wheat aphid -- Research -- South Africa Barley -- Disease and pest resistance -- South Africa Callose Aphids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50311 , vital:25975
- Description: The Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is a major pest of cultivated small grains. It is particularly devastating because of is high reproductive rate which results in the growth of large populations which become damaging to its host plants. Development of resistant barley (Hordeum vulgare L.) cultivars is complicated as resistance is polygenic. As a result, the industry remains at risk now that the RWA has spread throughout South Africa. It has, as recently as, 2013, been identified in the SW Cape, which was previously geographically isolated. This is South Africa‟s principle barley growing region. Now a potentially huge problem exists. Therefore, it is imperative that an alternative to pesticide use is found. Testing potential innate resistance in barley cultivars is thus, critical. In this thesis, I present data on four barely cultivars where I have examined their resistance/ lack of resistance to three known RWA biotypes, RWASA1, RWASA2 and RWASA3. The barley varieties used were two economically important South African malt barley cultivars (S5 and SSG 564) along with two potentially RWA resistant Afghan accessions (CIho 4125 and CIho 4159). The RWA biotype population growth rates on each of the plants were determined over a 14 day period. The aim was to establish baseline data of the effects of RWA population growth on the host plants under ambient CO2 (380 – 400 ppm) conditions. The extent of RWA feeding damage was investigated at the cell level by examining saliva deposition and cell disruption using Transmission Electron Microscopy; at the tissue/vascular level using fluorescence microscopy, to determine the extent of callose formation; at a whole leaf level by recording percent chlorosis and leaf roll; and finally, at a whole plant level by measuring biomass loss.The experiments were repeated under elevated CO2 (450 ppm) to model any changes in RWA/plant interaction with respect to future climate change. The effects of an elevated CO2 environment and RWA feeding on host plant foliar N and C:N ratio were compared to ambient CO2 conditions, to provide a clearer picture of the potential nutrient drain that a feeding RWA colony exacts on its host. Of the varieties tested, the CIho accessions performed better than the two SA barley cultivars as the CIho accessions appeared to express a mild antibiosis resistance response as RWA populations, particularly those of RWASA1, were smaller than those observed on either S5 or SSG 564. In addition, less damage was evident in the two CIho accessions due to RWA feeding. II RWASA2 was the most virulent of the three RWA biotypes tested, followed by RWASA3 while RWASA1 was the least virulent. Under elevated CO2 conditions, RWA feeding damage was exacerbated but the trend of biotype virulence remained the same. Higher aphid population sizes were recorded under elevated CO2, meant that even the more resistant CIho accessions were overcome by the increased demand made by the larger aphid colonies on the host plants. The % foliar N data showed that under elevated CO2 aphid-free control plants had increased N levels in their leaves. Increased “food” supply (as shown by the increased N levels) therefore allowed significantly larger aphid populations to develop on the plants exposed to elevated CO2, due to improved nutrient status of the phloem sap taken up by RWA. The knock-on effect of a higher aphid population was increased cell disruption as a result of extensive probing, extensive formations of wound callose, with the result that phloem damage impeded nutrient flow through the vascular tissues which contributed to chlorosis and (eventually plant) death. The major conclusion from this study is that even a mild CO2 elevation resulted in an increase aphid population which may pose a severe and very real threat to a barley crop. Therefore, without effort to identify and deploy resistant barley cultivars, it could well be possible that future barley cultivation in South Africa may no longer be viable.
- Full Text:
- Date Issued: 2016
- Authors: Sacranie, Sattar Farouk
- Date: 2016
- Subjects: Russian wheat aphid -- Research -- South Africa Barley -- Disease and pest resistance -- South Africa Callose Aphids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50311 , vital:25975
- Description: The Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is a major pest of cultivated small grains. It is particularly devastating because of is high reproductive rate which results in the growth of large populations which become damaging to its host plants. Development of resistant barley (Hordeum vulgare L.) cultivars is complicated as resistance is polygenic. As a result, the industry remains at risk now that the RWA has spread throughout South Africa. It has, as recently as, 2013, been identified in the SW Cape, which was previously geographically isolated. This is South Africa‟s principle barley growing region. Now a potentially huge problem exists. Therefore, it is imperative that an alternative to pesticide use is found. Testing potential innate resistance in barley cultivars is thus, critical. In this thesis, I present data on four barely cultivars where I have examined their resistance/ lack of resistance to three known RWA biotypes, RWASA1, RWASA2 and RWASA3. The barley varieties used were two economically important South African malt barley cultivars (S5 and SSG 564) along with two potentially RWA resistant Afghan accessions (CIho 4125 and CIho 4159). The RWA biotype population growth rates on each of the plants were determined over a 14 day period. The aim was to establish baseline data of the effects of RWA population growth on the host plants under ambient CO2 (380 – 400 ppm) conditions. The extent of RWA feeding damage was investigated at the cell level by examining saliva deposition and cell disruption using Transmission Electron Microscopy; at the tissue/vascular level using fluorescence microscopy, to determine the extent of callose formation; at a whole leaf level by recording percent chlorosis and leaf roll; and finally, at a whole plant level by measuring biomass loss.The experiments were repeated under elevated CO2 (450 ppm) to model any changes in RWA/plant interaction with respect to future climate change. The effects of an elevated CO2 environment and RWA feeding on host plant foliar N and C:N ratio were compared to ambient CO2 conditions, to provide a clearer picture of the potential nutrient drain that a feeding RWA colony exacts on its host. Of the varieties tested, the CIho accessions performed better than the two SA barley cultivars as the CIho accessions appeared to express a mild antibiosis resistance response as RWA populations, particularly those of RWASA1, were smaller than those observed on either S5 or SSG 564. In addition, less damage was evident in the two CIho accessions due to RWA feeding. II RWASA2 was the most virulent of the three RWA biotypes tested, followed by RWASA3 while RWASA1 was the least virulent. Under elevated CO2 conditions, RWA feeding damage was exacerbated but the trend of biotype virulence remained the same. Higher aphid population sizes were recorded under elevated CO2, meant that even the more resistant CIho accessions were overcome by the increased demand made by the larger aphid colonies on the host plants. The % foliar N data showed that under elevated CO2 aphid-free control plants had increased N levels in their leaves. Increased “food” supply (as shown by the increased N levels) therefore allowed significantly larger aphid populations to develop on the plants exposed to elevated CO2, due to improved nutrient status of the phloem sap taken up by RWA. The knock-on effect of a higher aphid population was increased cell disruption as a result of extensive probing, extensive formations of wound callose, with the result that phloem damage impeded nutrient flow through the vascular tissues which contributed to chlorosis and (eventually plant) death. The major conclusion from this study is that even a mild CO2 elevation resulted in an increase aphid population which may pose a severe and very real threat to a barley crop. Therefore, without effort to identify and deploy resistant barley cultivars, it could well be possible that future barley cultivation in South Africa may no longer be viable.
- Full Text:
- Date Issued: 2016
Information security concerns around enterprise bring your own device adoption in South African higher education institutions
- Authors: Sauls, Gershwin Ashton
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3619 , vital:20530
- Description: The research carried out in this thesis is an investigation into the information security concerns around the use of personally-owned mobile devices within South African universities. This concept, which is more commonly known as Bring Your Own Device or BYOD has raised many data loss concerns for organizational IT Departments across various industries worldwide. Universities as institutions are designed to facilitate research and learning and as such, have a strong culture toward the sharing of information which complicates management of these data loss concerns even further. As such, the objectives of the research were to determine the acceptance levels of BYOD within South African universities in relation to the perceived security risks. Thereafter, an investigation into which security practices, if any, that South African universities are using to minimize the information security concerns was carried out by means of a targeted online questionnaire. An extensive literature review was first carried out to evaluate the motivation for the research and to assess advantages of using Smartphone and Tablet PC’s for work related purposes. Thereafter, to determine security concerns, other surveys and related work was consulted to determine the relevant questions needed by the online questionnaire. The quantity of comprehensive academic studies concerning the security aspects of BYOD within organizations was very limited and because of this reason, the research took on a highly exploratory design. Finally, the research deliberated on the results of the online questionnaire and concluded with a strategy for the implementation of a mobile device security strategy for using personally-owned devices in a work-related environment.
- Full Text:
- Date Issued: 2016
- Authors: Sauls, Gershwin Ashton
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3619 , vital:20530
- Description: The research carried out in this thesis is an investigation into the information security concerns around the use of personally-owned mobile devices within South African universities. This concept, which is more commonly known as Bring Your Own Device or BYOD has raised many data loss concerns for organizational IT Departments across various industries worldwide. Universities as institutions are designed to facilitate research and learning and as such, have a strong culture toward the sharing of information which complicates management of these data loss concerns even further. As such, the objectives of the research were to determine the acceptance levels of BYOD within South African universities in relation to the perceived security risks. Thereafter, an investigation into which security practices, if any, that South African universities are using to minimize the information security concerns was carried out by means of a targeted online questionnaire. An extensive literature review was first carried out to evaluate the motivation for the research and to assess advantages of using Smartphone and Tablet PC’s for work related purposes. Thereafter, to determine security concerns, other surveys and related work was consulted to determine the relevant questions needed by the online questionnaire. The quantity of comprehensive academic studies concerning the security aspects of BYOD within organizations was very limited and because of this reason, the research took on a highly exploratory design. Finally, the research deliberated on the results of the online questionnaire and concluded with a strategy for the implementation of a mobile device security strategy for using personally-owned devices in a work-related environment.
- Full Text:
- Date Issued: 2016
Classical and quantum picture of the interior of two-dimensional black holes
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
- Date Issued: 2016
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
- Date Issued: 2016
Bio-prospecting a Soil Metagenomic Library for Carbohydrate Active Esterases
- Authors: Shezi, Ntombifuthi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4172 , http://hdl.handle.net/10962/d1021266
- Description: Lignocellulosic biomass is a promising renewable resource on earth. Plant biomass contains fermentable sugars and other moieties that can be converted to biofuels or other chemicals. Enzymatic hydrolysis of these biopolymers is significant in the liberation of sugars for fermentation into desired products. Owing to its complex structure, synergistic action of enzymes is required for its degradation. Enzymes that are involved in biomass degradation include cellulases, hemicellulases and the accessory enzymes acetyl xylan esterases and ferulic acid esterases. Ferulic acid esterases (FAEs, EC 3.1.1.73), represent a subclass of carboxylester hydrolases (EC 3.1.1.-) that catalyse the release of hydroxycinnamic acids (such as ferulic acid, p-coumaric, ferulic, sinapic and caffeic acid) that are generally found esterified to polysaccharides, such as arabinoxylans. Hydroxycinnamic acids have widespread potential applications due to their antimicrobial, photoprotectant and antioxidant properties, as well as their use as flavour precursors. Therefore, this interesting group of FAEs has a potentially wide variety of applications in agriculture, food and pharmaceutical industries. In the search for novel biocatalysts, metagenomics is considered as an alternative approach to conventional microbe screening, therefore, searching for novel biocatalysts from a soil metagenome that harbours a unique diversity of biocatalyst is significant. The aim of this study was to extract DNA from soil associated with cattle manure and construct a soil metagenomic library using a fosmid based plasmid vector and subsequently functionally screen for ferulic acid esterases using ethyl ferulate as a model substrate. A total of 59 recombinant fosmids conferring ferulic acid esterase phenotypes were identified (Hit rate 1:3122) and the two fosmids that consistently showed high FAE activities were selected for further study. Following nucleotide sequencing and translational analysis, two fae encoding open reading frames (FAE9 and FAE27) of approximately 274 and 322 aa, respectively, were identified. The amino acid sequence of the two ORFs contained a classical conserved esterase/lipase G-x-S-x-G sequence motif. The two genes (fae9 and fae27) were successfully expressed in Escherichia coli BL21 (DE3) and the purified enzymes exhibited respective temperature optima of 50 °C and 40 °C, and respective pH optima of 6.0 and 7.0. Further biochemical characterisation showed that FAE9 and FAE27 have high substrate specificity, following the fact that EFA is the preferred substrate for FAE9 (kcat/Km value of 128 s−1.mM-1) and also the preferred substrate for FAE27 (kcat/Km value of 137 s−1.mM-1). This work proves that soil is a valuable environmental source for novel esterase screening through functional based metagenomic approach. Therefore, this method may be used to screen for other valuable enzymes from environmental sources using inexpensive natural sources to encourage the screening of specific enzymes. Biochemistry of the two isolated enzymes makes these enzymes to be useful in industrial applications due to broad substrate activity that could replace the specialised enzymes to complete plant biomass degradation.
- Full Text:
- Date Issued: 2016
- Authors: Shezi, Ntombifuthi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4172 , http://hdl.handle.net/10962/d1021266
- Description: Lignocellulosic biomass is a promising renewable resource on earth. Plant biomass contains fermentable sugars and other moieties that can be converted to biofuels or other chemicals. Enzymatic hydrolysis of these biopolymers is significant in the liberation of sugars for fermentation into desired products. Owing to its complex structure, synergistic action of enzymes is required for its degradation. Enzymes that are involved in biomass degradation include cellulases, hemicellulases and the accessory enzymes acetyl xylan esterases and ferulic acid esterases. Ferulic acid esterases (FAEs, EC 3.1.1.73), represent a subclass of carboxylester hydrolases (EC 3.1.1.-) that catalyse the release of hydroxycinnamic acids (such as ferulic acid, p-coumaric, ferulic, sinapic and caffeic acid) that are generally found esterified to polysaccharides, such as arabinoxylans. Hydroxycinnamic acids have widespread potential applications due to their antimicrobial, photoprotectant and antioxidant properties, as well as their use as flavour precursors. Therefore, this interesting group of FAEs has a potentially wide variety of applications in agriculture, food and pharmaceutical industries. In the search for novel biocatalysts, metagenomics is considered as an alternative approach to conventional microbe screening, therefore, searching for novel biocatalysts from a soil metagenome that harbours a unique diversity of biocatalyst is significant. The aim of this study was to extract DNA from soil associated with cattle manure and construct a soil metagenomic library using a fosmid based plasmid vector and subsequently functionally screen for ferulic acid esterases using ethyl ferulate as a model substrate. A total of 59 recombinant fosmids conferring ferulic acid esterase phenotypes were identified (Hit rate 1:3122) and the two fosmids that consistently showed high FAE activities were selected for further study. Following nucleotide sequencing and translational analysis, two fae encoding open reading frames (FAE9 and FAE27) of approximately 274 and 322 aa, respectively, were identified. The amino acid sequence of the two ORFs contained a classical conserved esterase/lipase G-x-S-x-G sequence motif. The two genes (fae9 and fae27) were successfully expressed in Escherichia coli BL21 (DE3) and the purified enzymes exhibited respective temperature optima of 50 °C and 40 °C, and respective pH optima of 6.0 and 7.0. Further biochemical characterisation showed that FAE9 and FAE27 have high substrate specificity, following the fact that EFA is the preferred substrate for FAE9 (kcat/Km value of 128 s−1.mM-1) and also the preferred substrate for FAE27 (kcat/Km value of 137 s−1.mM-1). This work proves that soil is a valuable environmental source for novel esterase screening through functional based metagenomic approach. Therefore, this method may be used to screen for other valuable enzymes from environmental sources using inexpensive natural sources to encourage the screening of specific enzymes. Biochemistry of the two isolated enzymes makes these enzymes to be useful in industrial applications due to broad substrate activity that could replace the specialised enzymes to complete plant biomass degradation.
- Full Text:
- Date Issued: 2016
Heavy mineral characterization and provenance interpretation of the Ecca Group of geological formations in Eastern Cape Province, South Africa
- Authors: Sinuka, Sikhulule
- Date: 2016
- Subjects: Minerals -- South Africa -- Eastern Cape -- Classification Geology -- South Africa -- Eastern Cape Formations (Geology) -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2911 , vital:28125
- Description: The aim of the research focuses on characterizing heavy mineral assemblages and interpretation of the provenance of the Ecca Group of in the Eastern Cape Province, South Africa. In South Africa, the Ecca Group outcrops extensively in the Main Karoo Basin. Mudstone, siltstone, sandstone, minor conglomerate and coal are the major constituent lithologies within the group. For descriptive purposes, the Ecca is categorized into three different geographical areas: the southern area, the western and northwestern area and the northeastern area. Six of the sixteen geological formations, namely the Prince Albert, Whitehill, Collingham, Ripon, Fort Brown, Waterford and Koonap Formations are present in the study area and are best exposed in road cuttings. For purposes of comparison, the underlying Witteberg Group, the Dwyka (which has Formation status here), and the overlying Koonap Formation of the Beaufort Group, are included in the study. This study is motivated by the relatively little information that is available on the heavy minerals of the Ecca Group, and that research of this nature had not been undertaken in the study area before. Another contributing motivation was to determine whether heavy mineral assemblages could be used to identify formations of the Ecca Group and for correlating between different localities in accordance with studies done elsewhere. Additionally, diagnostic heavy mineral assemblages could aid with stratigraphic selection of future boreholes in the Ecca Group. Heavy minerals are natural provenance tracers because of their stable nature and hydrodynamic behaviour. They are both non-opaque and opaque, with apatite, epidote, garnet, rutile, staurolite, tourmaline and zircon being good examples of non-opaque grains while ilmenite and magnetite are the most common opaques. Heavies are either derived from stable minor accessory minerals or from abundant but unstable mafic components of the host rock. They are very useful in interpreting the provenance due to the fact that some minerals are diagnostic of certain source rocks. However, sediments are exposed to several factors (conditions) such as weathering, erosion, breakage due to abrasion, mixing and recycling during transportation from the source to the depositional area. This implies that there are parameters other than the parent lithology that determine their final composition.
- Full Text:
- Date Issued: 2016
- Authors: Sinuka, Sikhulule
- Date: 2016
- Subjects: Minerals -- South Africa -- Eastern Cape -- Classification Geology -- South Africa -- Eastern Cape Formations (Geology) -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2911 , vital:28125
- Description: The aim of the research focuses on characterizing heavy mineral assemblages and interpretation of the provenance of the Ecca Group of in the Eastern Cape Province, South Africa. In South Africa, the Ecca Group outcrops extensively in the Main Karoo Basin. Mudstone, siltstone, sandstone, minor conglomerate and coal are the major constituent lithologies within the group. For descriptive purposes, the Ecca is categorized into three different geographical areas: the southern area, the western and northwestern area and the northeastern area. Six of the sixteen geological formations, namely the Prince Albert, Whitehill, Collingham, Ripon, Fort Brown, Waterford and Koonap Formations are present in the study area and are best exposed in road cuttings. For purposes of comparison, the underlying Witteberg Group, the Dwyka (which has Formation status here), and the overlying Koonap Formation of the Beaufort Group, are included in the study. This study is motivated by the relatively little information that is available on the heavy minerals of the Ecca Group, and that research of this nature had not been undertaken in the study area before. Another contributing motivation was to determine whether heavy mineral assemblages could be used to identify formations of the Ecca Group and for correlating between different localities in accordance with studies done elsewhere. Additionally, diagnostic heavy mineral assemblages could aid with stratigraphic selection of future boreholes in the Ecca Group. Heavy minerals are natural provenance tracers because of their stable nature and hydrodynamic behaviour. They are both non-opaque and opaque, with apatite, epidote, garnet, rutile, staurolite, tourmaline and zircon being good examples of non-opaque grains while ilmenite and magnetite are the most common opaques. Heavies are either derived from stable minor accessory minerals or from abundant but unstable mafic components of the host rock. They are very useful in interpreting the provenance due to the fact that some minerals are diagnostic of certain source rocks. However, sediments are exposed to several factors (conditions) such as weathering, erosion, breakage due to abrasion, mixing and recycling during transportation from the source to the depositional area. This implies that there are parameters other than the parent lithology that determine their final composition.
- Full Text:
- Date Issued: 2016
An evaluation of medicinal plants used in South Africa and Lesotho for uterotonic contractile purposes
- Authors: Smit, Inge
- Date: 2016
- Subjects: Traditional medicine -- South Africa Traditional medicine -- Lesotho
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15232 , vital:40256
- Description: Background One of the leading cause of maternal mortality globally is postpartum haemorrhage (PPH), which mainly occur in developing countries. By identifying traditional medicinal plants that is used by Traditional birth attendants we can analysis the plants for cyclotides which contain uterotonic properties and a wide variety of other properties. The indigenous knowledge of traditional medicinal plants need to be preserved and scientifically proven to ensure future drug development and continued use of these plants. Cyclotides can be used as a backbone to develop novel drugs in that cyclotides are very stable proteins. Methods: Ten plants were identified that are commonly used to prevent or treat postpartum haemorrhage. The plant samples were collected, prepared and dried in South Africa. The plants were analysed in Austria. The plants underwent extraction of one gram of each plant was analysed using: Matrix-Assisted Laser desorption Ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS); Tandem Mass Spectrometry and Analysis by High-performance Liquid Chromatography (HPLC). Results None of the ten plants analysed showed the presence of cyclotides. It is important to report negative results, because it informs the academic fraternity and could be entered in a global data base of results. The plants analysed is known to be used by Traditional Birth Attendants for the treatment or prevention of postpartum haemorrhage. Conclusion All the plants analysed are commonly used to prevent and treat PPH. The fact that no cyclotides were found do not dispute the practical use of these plants to prevent and treat PPH. There continue to be a gap in what uterotonic properties these plants contain and should be further investigated.
- Full Text:
- Date Issued: 2016
- Authors: Smit, Inge
- Date: 2016
- Subjects: Traditional medicine -- South Africa Traditional medicine -- Lesotho
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15232 , vital:40256
- Description: Background One of the leading cause of maternal mortality globally is postpartum haemorrhage (PPH), which mainly occur in developing countries. By identifying traditional medicinal plants that is used by Traditional birth attendants we can analysis the plants for cyclotides which contain uterotonic properties and a wide variety of other properties. The indigenous knowledge of traditional medicinal plants need to be preserved and scientifically proven to ensure future drug development and continued use of these plants. Cyclotides can be used as a backbone to develop novel drugs in that cyclotides are very stable proteins. Methods: Ten plants were identified that are commonly used to prevent or treat postpartum haemorrhage. The plant samples were collected, prepared and dried in South Africa. The plants were analysed in Austria. The plants underwent extraction of one gram of each plant was analysed using: Matrix-Assisted Laser desorption Ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS); Tandem Mass Spectrometry and Analysis by High-performance Liquid Chromatography (HPLC). Results None of the ten plants analysed showed the presence of cyclotides. It is important to report negative results, because it informs the academic fraternity and could be entered in a global data base of results. The plants analysed is known to be used by Traditional Birth Attendants for the treatment or prevention of postpartum haemorrhage. Conclusion All the plants analysed are commonly used to prevent and treat PPH. The fact that no cyclotides were found do not dispute the practical use of these plants to prevent and treat PPH. There continue to be a gap in what uterotonic properties these plants contain and should be further investigated.
- Full Text:
- Date Issued: 2016
Penguin parenting : assortative mating, nest attendance and sex-specific chick provisioning in the African Penguin (Spheniscus demersus)
- Authors: Smith, Diane Lauren
- Date: 2016
- Subjects: African penguin , Penguins -- South Africa , Penguins -- Sexual behavior , Parental behavior in animals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5943 , http://hdl.handle.net/10962/d1019993
- Description: Animal behaviour is especially sensitive to environmental variability and prey availability during the breeding season, and this is particularly true for non-volant, central place foragers such as the endangered African Penguin (Spheniscus demersus). Individual sex and morphology, as well as the level of assortment within mated pairs can influence both the behaviour and the reproductive success of species exhibiting biparental care. This study made use of a large biometric database and nest attendance video footage to determine the influence of intrinsic (assortative mating, brood size and chick age) and extrinsic (environmental conditions, anthropic disturbance) factors on breeding behaviour and performance of African Penguins on Bird Island, Algoa Bay, during peak breeding (March - July) in 2013. While sexual dimorphism in African Penguins is subtle, the colony-specific discriminant functions presented here provide an accurate sexing tool when only bill and flipper length are available. Despite the premise that selection of a large, high-quality mate in this longlived, monogamous seabird governs lifetime fitness, only low levels of assortative mating were found, and this only for earlier breeders, when larger females (but not males) bred. The 2013 season was a particularly successful one, coinciding with above-average sardine and anchovy abundance, and almost 80 percent of monitored nests were double-brooded, with very low levels of mortality. A- and B-chicks of double broods and singleton chicks grew at similar rates and exhibited similar body condition indices. In these conditions, chick developmental rates were independent of parental size, assortment or provisioning behaviour. Females raising a double brood were significantly lighter and in poorer body condition than those raising a single chick, although the same trend was not evident in males. Offspring sex ratio in 2013 (2.27:1) favoured male chicks, suggesting that there is potential to over-produce the larger sex when resources are plentiful. Peak nest arrival and departure times of parents did not change over the course of monitored breeding attempts (March-June), nor were they different for disturbed and undisturbed nests or for a single or double brood. The increase in CCTV-observed provisioning rate as chicks grew larger was best explained by brood size, at-sea chlorophyll a concentration, and maximum air temperature, but was unrelated to parental morphology or assortative index. Importantly, parental absenteeism commenced earlier and was markedly greater in nests frequently handled by researchers than in undisturbed nests. Both the time spent together by parents, and absenteeism were measurably affected by maximum afternoon air temperatures, the effects of which are expected to be exacerbated by poorer foraging conditions and climate change. A third of manually-monitored nests shared chick-guarding duties unequally, although this phenomenon was independent of parental sex or morphology. The adaptive benefits of mating patterns and division of labour during chick-rearing may only become apparent in a year of below-average food availability and it is highly recommended that this study be repeated in a year of scarce food resources. These findings augment past foraging ecology studies and demonstrate that investigator disturbance and environmental conditions can affect the nesting behaviour of this highly threatened seabird.
- Full Text:
- Date Issued: 2016
- Authors: Smith, Diane Lauren
- Date: 2016
- Subjects: African penguin , Penguins -- South Africa , Penguins -- Sexual behavior , Parental behavior in animals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5943 , http://hdl.handle.net/10962/d1019993
- Description: Animal behaviour is especially sensitive to environmental variability and prey availability during the breeding season, and this is particularly true for non-volant, central place foragers such as the endangered African Penguin (Spheniscus demersus). Individual sex and morphology, as well as the level of assortment within mated pairs can influence both the behaviour and the reproductive success of species exhibiting biparental care. This study made use of a large biometric database and nest attendance video footage to determine the influence of intrinsic (assortative mating, brood size and chick age) and extrinsic (environmental conditions, anthropic disturbance) factors on breeding behaviour and performance of African Penguins on Bird Island, Algoa Bay, during peak breeding (March - July) in 2013. While sexual dimorphism in African Penguins is subtle, the colony-specific discriminant functions presented here provide an accurate sexing tool when only bill and flipper length are available. Despite the premise that selection of a large, high-quality mate in this longlived, monogamous seabird governs lifetime fitness, only low levels of assortative mating were found, and this only for earlier breeders, when larger females (but not males) bred. The 2013 season was a particularly successful one, coinciding with above-average sardine and anchovy abundance, and almost 80 percent of monitored nests were double-brooded, with very low levels of mortality. A- and B-chicks of double broods and singleton chicks grew at similar rates and exhibited similar body condition indices. In these conditions, chick developmental rates were independent of parental size, assortment or provisioning behaviour. Females raising a double brood were significantly lighter and in poorer body condition than those raising a single chick, although the same trend was not evident in males. Offspring sex ratio in 2013 (2.27:1) favoured male chicks, suggesting that there is potential to over-produce the larger sex when resources are plentiful. Peak nest arrival and departure times of parents did not change over the course of monitored breeding attempts (March-June), nor were they different for disturbed and undisturbed nests or for a single or double brood. The increase in CCTV-observed provisioning rate as chicks grew larger was best explained by brood size, at-sea chlorophyll a concentration, and maximum air temperature, but was unrelated to parental morphology or assortative index. Importantly, parental absenteeism commenced earlier and was markedly greater in nests frequently handled by researchers than in undisturbed nests. Both the time spent together by parents, and absenteeism were measurably affected by maximum afternoon air temperatures, the effects of which are expected to be exacerbated by poorer foraging conditions and climate change. A third of manually-monitored nests shared chick-guarding duties unequally, although this phenomenon was independent of parental sex or morphology. The adaptive benefits of mating patterns and division of labour during chick-rearing may only become apparent in a year of below-average food availability and it is highly recommended that this study be repeated in a year of scarce food resources. These findings augment past foraging ecology studies and demonstrate that investigator disturbance and environmental conditions can affect the nesting behaviour of this highly threatened seabird.
- Full Text:
- Date Issued: 2016
Genotypic and phenotypic characterization of enterococci from cow dung and environmental water sources in three selected dairy farms in Amathole District
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016
An investigation of the aquatic macroinvertebrate fauna of the southern Great Escarpment (South Africa): insights from ecological and genetic studies
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
- Date Issued: 2016
Mesopredator release and the effectiveness of camera traps for estimating mammal abundances in the Eastern Cape, South Africa
- Authors: Taylor, Jonathan Michael
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3587 , vital:20527
- Description: Remotely operated cameras (camera traps) have become an indispensable tool for many ecologists, particularly those studying rare and elusive animals. A plethora of camera trap makes and models are now commercially available, yet the effects of their varying design features on the quality and quantity of data recorded remains principally unknown. Better understanding of differing camera trap designs is needed before adequate management policies can be implemented, especially when the aim is to protect vulnerable and endangered species such as many carnivores. Habitat loss and human conflict has prompted worldwide declines of apex predator populations. Following this, many smaller predators have undergone population ‘explosions’ due to the lack of top-down forcing, a phenomenon known as mesopredator release. Land use changes in the Eastern Cape of South Africa have caused extensive degradation and fragmentation of the Subtropical Thicket Biome. In addition, coupled with anthropogenic persecution, apex predators including lions (Panthera leo), leopards (P. pardus), and brown hyaenas (Hyaena brunnea) have been extirpated from large areas of their historic range. Removal of these apex predators may provide opportunity for mesopredators, such as black-backed jackals (Canis mesomelas) and caracals (Caracal caracal), to be released from top-down forcing and possibly initiate trophic cascade effects. Therefore, using randomly distributed camera traps, my study aimed to explore the quality and quantity of data collected by different camera trap designs, and to investigate the mesopredator release hypothesis in the Eastern Cape of South Africa. A total of 2,989 trap nights was used to compare camera trap designs. Camera traps with narrow detection zones and fast trigger speeds (≤ 0.25 seconds) recorded a higher diversity of carnivores, but there was no significant difference in the relative abundances of carnivore species recorded by different camera trap models. A total of 19,659 trap nights was used to assess mesopredator relative abundance, occupancy, distribution and daily activity patterns at one site with, and one site without, apex predators. Consistent with the mesopredator release hypothesis, black-backed jackal relative abundance was significantly higher in the absence of apex predators, and this was supported by occupancy analyses. Further, black-backed jackal distribution was significantly concentrated in areas where apex predator activity was low, possibly indicating spatial avoidance. There was no significant difference in caracal relative abundance, occupancy, distribution, or daily activity between sites. These results provide the first indication of mesopredator release of blackbacked jackals in the Eastern Cape. The implications of black-backed jackal release including prey population structure, local extinctions, altered seed dispersal and disease dynamics are discussed.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Jonathan Michael
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3587 , vital:20527
- Description: Remotely operated cameras (camera traps) have become an indispensable tool for many ecologists, particularly those studying rare and elusive animals. A plethora of camera trap makes and models are now commercially available, yet the effects of their varying design features on the quality and quantity of data recorded remains principally unknown. Better understanding of differing camera trap designs is needed before adequate management policies can be implemented, especially when the aim is to protect vulnerable and endangered species such as many carnivores. Habitat loss and human conflict has prompted worldwide declines of apex predator populations. Following this, many smaller predators have undergone population ‘explosions’ due to the lack of top-down forcing, a phenomenon known as mesopredator release. Land use changes in the Eastern Cape of South Africa have caused extensive degradation and fragmentation of the Subtropical Thicket Biome. In addition, coupled with anthropogenic persecution, apex predators including lions (Panthera leo), leopards (P. pardus), and brown hyaenas (Hyaena brunnea) have been extirpated from large areas of their historic range. Removal of these apex predators may provide opportunity for mesopredators, such as black-backed jackals (Canis mesomelas) and caracals (Caracal caracal), to be released from top-down forcing and possibly initiate trophic cascade effects. Therefore, using randomly distributed camera traps, my study aimed to explore the quality and quantity of data collected by different camera trap designs, and to investigate the mesopredator release hypothesis in the Eastern Cape of South Africa. A total of 2,989 trap nights was used to compare camera trap designs. Camera traps with narrow detection zones and fast trigger speeds (≤ 0.25 seconds) recorded a higher diversity of carnivores, but there was no significant difference in the relative abundances of carnivore species recorded by different camera trap models. A total of 19,659 trap nights was used to assess mesopredator relative abundance, occupancy, distribution and daily activity patterns at one site with, and one site without, apex predators. Consistent with the mesopredator release hypothesis, black-backed jackal relative abundance was significantly higher in the absence of apex predators, and this was supported by occupancy analyses. Further, black-backed jackal distribution was significantly concentrated in areas where apex predator activity was low, possibly indicating spatial avoidance. There was no significant difference in caracal relative abundance, occupancy, distribution, or daily activity between sites. These results provide the first indication of mesopredator release of blackbacked jackals in the Eastern Cape. The implications of black-backed jackal release including prey population structure, local extinctions, altered seed dispersal and disease dynamics are discussed.
- Full Text:
- Date Issued: 2016
The use of treated brewery effluent as a water and nutrient source in crop irrigation
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Richard Peter
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5390 , http://hdl.handle.net/10962/d1021265
- Description: Brewery effluent (BE) needs to be treated before it can be released into the environment, reused or used in down-stream activities. Current technologies used to address this concern at the experimental wastewater treatment plant at Ibahyi Brewery (SAB Ltd) include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW). The aim of this work was to determine if BE treated in these systems might be suitable for crop irrigation. A test crop, cabbage (Brassica oleracea cv. Star 3301), grew best on post-AD and post-PFP BE compared to those irrigated with post-HRAP or post-CW effluent. However, the yield was 13% lower than cabbage plants irrigated with a commercial nutrient solution and fresh water. The relatively high conductivity (3019.05 ± 48.72 μs/cm2) of BE may be the main factor reducing the cabbage yields. Post-HRAP and post-CW BE were the least suitable for irrigated crop production due to the higher conductivity and lower nutrient content of these treated effluents. After three months, soils irrigated with post-AD and post-PFP BE had a significantly higher sodium content and sodium adsorption ratio (3919 ± 94.77 mg/kg & 8.18 ± 0.17) than soil irrigated with a commercial nutrient solution (920.58 ± 27.46 mg/kg & 2.20 ± 0.05; p<0.05). However, this was not accompanied by a deterioration in the soil’s hydro-physical properties, nor a change in the metabolic community structure of the soil (p>0.05). After prolonged irrigation with treated BE, sodium is likely to build up in the soil and this can be expected to be accompanied by a deterioration in the soil physical structure. However, crops species such as millet (Echinochloa esculenta), lucerne (Medicago sativa) and saltbush (Atriplex nummularia) reduced the build-up of sodium in the soil. The results suggest that sodium was mainly removed from the soil through plant-assisted leaching. Of the crops grown, lucerne showed the most promise because it improved the soil physical properties, is able to grow well in alkaline environments, is a popular fodder crop and can be harvested multiple times from a single stand. Brewery effluent is more suitable for soil production systems than hydroponic production systems because the soil was able to act as a buffer against the high pH of post-AD BE, whereas in a hydroponics systems the high pH reduced the availability of key minerals to plants. In conclusion brewery effluent contains sufficient plants nutrients to support the growth of cabbages, saltbush, lucerne and millet. However the sodium content of BE is a concern as it accumulates in the soil, and in the long-term it may lead to soil degradation. It is suggested that the brewery change the pH neutralising treatment of BE from sodium hydroxide to potassium hydroxide, or dolomitic lime (calcium and magnesium carbonate) because this would reduce the introduction of sodium into the system, and would increase the suitability of BE for crop production, given potassium and calcium are plant nutrients. The benefits of developing this nutrient and water resource could contribute to cost-reductions at the brewery, more efficient water, nutrient and energy management, create job opportunities with the potential of improving food security in the local community.
- Full Text:
- Date Issued: 2016
Seasonal variations of essential oil composition and some biological evaluation of Pelargonium inquinans (L.) Ait. South Africa
- Authors: Tembeni, Babalwa
- Date: 2016
- Subjects: Pelargoniums Essences and essential oils Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6281 , vital:29537
- Description: Pelargonium inquinans which belongs to the family Geraniaceae, is an essential oil yielding plant. P. inquinans was collected from two different sites in Grahamstown (wild) and Alice, at the University of Fort Hare botanical garden. Authentication of the plant was done by Dr. T. Dold at Schonland herbarium, and the voucher specimen being T01. This study is focused at determining the chemical constituents and biological properties of the essential oils of wild and cultivated P. inquinans across different seasons, as the plant grows throughout the year. Seasonal collection of wild and cultivated P. inquinans was achieved in a duration of 12 months. 32 essential oil samples of P. inquinans were obtained by extraction using hydro-distillation technique for 3-4 hours. The chemical composition of the essential oils was determined using GC/MS and GC/FID. Amongst the 32 essential oils only 4 samples wild ( fresh stem and leaf) and cultivated ( fresh stem and leaf) from summer season were evaluated for analgesic activity using acetic acid induced writhings and hot plate nociception models in mice, anti-inflammatory activity was determined on the egg albumin- induced rat paw oedema in rats. The results obtained from GC-MS revealed a total of 169 components obtained from the leafstem, fresh/dry wild and cultivated P. inquinans. These essential oils showed a great deal of chemotaxonomic variation and similarity in the major and minor components along the season. In spring season the essential oils of wild and cultivated P. inquinans had abundance of hydrogenated sesquiterpenes (20.6percent-66.7percent). The major components were found to be α-caryophyllene (9.1percent-26.8percent), p-xylene (23.3percent-27.5percent), β-caryophyllene (11.4percent-30.9percent), o-xylene (6.3percent-39.4percent), β-thujene (8.7percent), isocaryophyllene (13.9percent), isoborneol (14.2percent), β-myrcene (5.7percent), geranyl acetate (13.8percent), toluene (7.9percent), β-gurjunene (18.5percent), α-cadinene (15.8percent), β-farnesene (14.2percent), 3-carene (12.1percent) and camphene (9.0percent). In summer season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (50.3percent- 63.0percent), oxygenated monoterpenes (30.4percent) and hydrogenated monoterpenes (20.8percent- 61.0percent). The major components were found to be α-caryophyllene (12.3percent-25.8percent), β-caryophyllene (15.1percent- 31.7percent), trans-caryophyllene (10.3percent- 17.8percent), phytol (14.2percent- 20.2percent), camphor (46.5percent), sabinene (27.8percent), elemol (18.1percent), z3-hexenyl isobutyrate (16.3percent), limonene (12.1percent), menthone (12.1percent)< E.E-β-farnesene (14.7percent), palmitic acid (9.6percent), eugenol (9.4percent), cis- β-ocimene (8.7percent), α-terpineol (8.7percent), geranyl acetone (7.8percent), β- humulene (7.5percent). linoleic acid (7.4percent), trans-linalool oxide (7.4percent), β-bisabolene (7.1percent), cis- linalool oxide (7.1percent), ionone (6.9percent), caryophyllene oxide (6.9percent) and germacrene d (6.3percent). In autumn season the essential oils of wild and cultivated P. inquinans were found to be rich in hydrogenated sesquiterpenes (29.3percent- 65.2percent) and oxygenated sesquiterpenes (22.8percent- 31.4percent). The major components were found to be α-caryophyllene (15.5percent- 23.4percent), β-caryophyllene (15.2percent- 17.2percent), β-myrcene (7.7percent-13.8percent), β-humulene (8.7percent- 15.2percent), caryophyllene oxide (9.8- 16.2percent), trans- caryophyllene (16.7percent- 23.3percent), α-humulene (11.8percent- 18.6percent), linoleic acid (11.2percent), palmitic acid (10.4percent), phytol acetate (8.5percent), -longipinene (8.3percent) and citronellol (7.8percent). In winter season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (25.1percent- 48.6percent), oxygenated monoterpenes (47.6percent), oxygenated sesquiterpenes (22.2percent- 28.0percent). The major components were found to be β-caryophyllene (14.6percent- 23.0percent), α-caryophyllene (9.4percent- 18.0percent), trans- caryophyllene (12.2percent- 14.6percent), α-cedrene (26.2percent), germacrene –d-4-ol (16.8percent), 2,6-dihydroxyacetophenone (15.6percent), (+) epibicyclosesquiphellandrene (15.3percent), E-β- farnesene (13.0percent), β-phellandrene (11.7percent), 2-nitrophenol (9.5percent), palatinol (8.4percent), geranyl acetate (7.7percent) and linoleic acid (7.4percent). The oils from the wild and cultivated sources showed significant (p<0.05-0.001) decrease in number of writhes induced by the acetic acid compared to vehicle; caused significant (p<0.05-0.001) delay in reaction time on the hot plate at 60 and 90 min post-treatment and significantly (p<0.05-0.001) reduced oedema size caused by the egg albumin injection compared to the vehicle. The oils from the wild plant showed more potency compared to the cultivated. The essential oils of wild and cultivated P. inquinans showed qualitative, quantitative and chemotaxonomic variation with analgesic and anti-inflammatory activity. These essential oils need to be explored for further biological analysis because of the major components they contain.
- Full Text:
- Date Issued: 2016
- Authors: Tembeni, Babalwa
- Date: 2016
- Subjects: Pelargoniums Essences and essential oils Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6281 , vital:29537
- Description: Pelargonium inquinans which belongs to the family Geraniaceae, is an essential oil yielding plant. P. inquinans was collected from two different sites in Grahamstown (wild) and Alice, at the University of Fort Hare botanical garden. Authentication of the plant was done by Dr. T. Dold at Schonland herbarium, and the voucher specimen being T01. This study is focused at determining the chemical constituents and biological properties of the essential oils of wild and cultivated P. inquinans across different seasons, as the plant grows throughout the year. Seasonal collection of wild and cultivated P. inquinans was achieved in a duration of 12 months. 32 essential oil samples of P. inquinans were obtained by extraction using hydro-distillation technique for 3-4 hours. The chemical composition of the essential oils was determined using GC/MS and GC/FID. Amongst the 32 essential oils only 4 samples wild ( fresh stem and leaf) and cultivated ( fresh stem and leaf) from summer season were evaluated for analgesic activity using acetic acid induced writhings and hot plate nociception models in mice, anti-inflammatory activity was determined on the egg albumin- induced rat paw oedema in rats. The results obtained from GC-MS revealed a total of 169 components obtained from the leafstem, fresh/dry wild and cultivated P. inquinans. These essential oils showed a great deal of chemotaxonomic variation and similarity in the major and minor components along the season. In spring season the essential oils of wild and cultivated P. inquinans had abundance of hydrogenated sesquiterpenes (20.6percent-66.7percent). The major components were found to be α-caryophyllene (9.1percent-26.8percent), p-xylene (23.3percent-27.5percent), β-caryophyllene (11.4percent-30.9percent), o-xylene (6.3percent-39.4percent), β-thujene (8.7percent), isocaryophyllene (13.9percent), isoborneol (14.2percent), β-myrcene (5.7percent), geranyl acetate (13.8percent), toluene (7.9percent), β-gurjunene (18.5percent), α-cadinene (15.8percent), β-farnesene (14.2percent), 3-carene (12.1percent) and camphene (9.0percent). In summer season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (50.3percent- 63.0percent), oxygenated monoterpenes (30.4percent) and hydrogenated monoterpenes (20.8percent- 61.0percent). The major components were found to be α-caryophyllene (12.3percent-25.8percent), β-caryophyllene (15.1percent- 31.7percent), trans-caryophyllene (10.3percent- 17.8percent), phytol (14.2percent- 20.2percent), camphor (46.5percent), sabinene (27.8percent), elemol (18.1percent), z3-hexenyl isobutyrate (16.3percent), limonene (12.1percent), menthone (12.1percent)< E.E-β-farnesene (14.7percent), palmitic acid (9.6percent), eugenol (9.4percent), cis- β-ocimene (8.7percent), α-terpineol (8.7percent), geranyl acetone (7.8percent), β- humulene (7.5percent). linoleic acid (7.4percent), trans-linalool oxide (7.4percent), β-bisabolene (7.1percent), cis- linalool oxide (7.1percent), ionone (6.9percent), caryophyllene oxide (6.9percent) and germacrene d (6.3percent). In autumn season the essential oils of wild and cultivated P. inquinans were found to be rich in hydrogenated sesquiterpenes (29.3percent- 65.2percent) and oxygenated sesquiterpenes (22.8percent- 31.4percent). The major components were found to be α-caryophyllene (15.5percent- 23.4percent), β-caryophyllene (15.2percent- 17.2percent), β-myrcene (7.7percent-13.8percent), β-humulene (8.7percent- 15.2percent), caryophyllene oxide (9.8- 16.2percent), trans- caryophyllene (16.7percent- 23.3percent), α-humulene (11.8percent- 18.6percent), linoleic acid (11.2percent), palmitic acid (10.4percent), phytol acetate (8.5percent), -longipinene (8.3percent) and citronellol (7.8percent). In winter season the essential oils of wild and cultivated P. inquinans were found to have abundance of hydrogenated sesquiterpenes (25.1percent- 48.6percent), oxygenated monoterpenes (47.6percent), oxygenated sesquiterpenes (22.2percent- 28.0percent). The major components were found to be β-caryophyllene (14.6percent- 23.0percent), α-caryophyllene (9.4percent- 18.0percent), trans- caryophyllene (12.2percent- 14.6percent), α-cedrene (26.2percent), germacrene –d-4-ol (16.8percent), 2,6-dihydroxyacetophenone (15.6percent), (+) epibicyclosesquiphellandrene (15.3percent), E-β- farnesene (13.0percent), β-phellandrene (11.7percent), 2-nitrophenol (9.5percent), palatinol (8.4percent), geranyl acetate (7.7percent) and linoleic acid (7.4percent). The oils from the wild and cultivated sources showed significant (p<0.05-0.001) decrease in number of writhes induced by the acetic acid compared to vehicle; caused significant (p<0.05-0.001) delay in reaction time on the hot plate at 60 and 90 min post-treatment and significantly (p<0.05-0.001) reduced oedema size caused by the egg albumin injection compared to the vehicle. The oils from the wild plant showed more potency compared to the cultivated. The essential oils of wild and cultivated P. inquinans showed qualitative, quantitative and chemotaxonomic variation with analgesic and anti-inflammatory activity. These essential oils need to be explored for further biological analysis because of the major components they contain.
- Full Text:
- Date Issued: 2016
Reproductive biology of important invasive plants in the Eastern Cape Province of South Africa
- Authors: Thorne, Cara-Jayne
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3683 , vital:20535
- Description: Baker’s rule predicts species capable of uniparental reproduction are more likely to establish after long distance dispersal (or introduction in the case of invasive plants), thus the ability to undergo autonomous self-pollination should promote colonization. An investigation into the reproductive biology of eleven invasive species in the Eastern Cape Province of South Africa between 2012 and 2014 showed strong support for Baker’s law. Breeding system results showed evidence of self-compatibility in eight species, ten species were capable of autonomous self-pollination, and only three species showed evidence of varying levels of self-incompatibility. These results provide evdence that autonomous self-pollination occurs more frequently among invasive species, self-compatible species more frequently become invasive compared with self-incompatible species and that autogamous species should have a larger invasive range. Co-opting suitable local pollinators may be problematic for invasive plants, especially those with highly specialized pollination systems. The species investigated appear to be largely independent of pollinators, mostly setting seed in the absence of pollinators. Despite this, all eleven invasive plant species are regularly visited by a variety of generalist pollinators including Apis mellifera, Xylocopa bees and Allodapini species. Pollinators all carried substantial pollen loads, even managing to extract pollen from more specialized plants, such as the poricidal anthers of Solanum species, and frequently came into contact with both anthers and stigmas. Considering most of theses species are capable of autonomous self-pollination, their reliance on pollinators may be low. Even the most self-incompatible species, Passiflora caerulea, appears to have successfully co-opted local pollinators (honeybees and carpenter bees), ensuring successful pollination and seed set. The ability for cross-pollination by local pollinators allows for some degree of genetic variation within invasive plant populations, especially for self-incompatible species. Inadequate pollen deposition by unreliable or inefficient pollinators, or reduced resource availability, can result in pollen limitation. Invasive plant species may be especially susceptible, with three of the plant species investiagted showing possible pollen limitation at the level of seed set, while the remaining nine invasive plant species showed no evidence of pollen limitation in South Africa. The ability to utilize uniparental reproduction (as Baker’s law predicted), and co-opt local pollinators has allowed invasive plants in the Eastern Cape to successfully establish and persist after introduction. Hence, the inclusion of reproductive traits of plants should therefore be included in risk assessments for future plant invaders.
- Full Text:
- Date Issued: 2016
- Authors: Thorne, Cara-Jayne
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3683 , vital:20535
- Description: Baker’s rule predicts species capable of uniparental reproduction are more likely to establish after long distance dispersal (or introduction in the case of invasive plants), thus the ability to undergo autonomous self-pollination should promote colonization. An investigation into the reproductive biology of eleven invasive species in the Eastern Cape Province of South Africa between 2012 and 2014 showed strong support for Baker’s law. Breeding system results showed evidence of self-compatibility in eight species, ten species were capable of autonomous self-pollination, and only three species showed evidence of varying levels of self-incompatibility. These results provide evdence that autonomous self-pollination occurs more frequently among invasive species, self-compatible species more frequently become invasive compared with self-incompatible species and that autogamous species should have a larger invasive range. Co-opting suitable local pollinators may be problematic for invasive plants, especially those with highly specialized pollination systems. The species investigated appear to be largely independent of pollinators, mostly setting seed in the absence of pollinators. Despite this, all eleven invasive plant species are regularly visited by a variety of generalist pollinators including Apis mellifera, Xylocopa bees and Allodapini species. Pollinators all carried substantial pollen loads, even managing to extract pollen from more specialized plants, such as the poricidal anthers of Solanum species, and frequently came into contact with both anthers and stigmas. Considering most of theses species are capable of autonomous self-pollination, their reliance on pollinators may be low. Even the most self-incompatible species, Passiflora caerulea, appears to have successfully co-opted local pollinators (honeybees and carpenter bees), ensuring successful pollination and seed set. The ability for cross-pollination by local pollinators allows for some degree of genetic variation within invasive plant populations, especially for self-incompatible species. Inadequate pollen deposition by unreliable or inefficient pollinators, or reduced resource availability, can result in pollen limitation. Invasive plant species may be especially susceptible, with three of the plant species investiagted showing possible pollen limitation at the level of seed set, while the remaining nine invasive plant species showed no evidence of pollen limitation in South Africa. The ability to utilize uniparental reproduction (as Baker’s law predicted), and co-opt local pollinators has allowed invasive plants in the Eastern Cape to successfully establish and persist after introduction. Hence, the inclusion of reproductive traits of plants should therefore be included in risk assessments for future plant invaders.
- Full Text:
- Date Issued: 2016
The biomass production, nutrient content and silage quality of Perennial ryegrass (Lolium perenne (L)) Cocksfoot (Dactylis glomerata (L)) and Tall fescue (Festuca arundinacea (Schreb)) varieties grown under irrigation in Alice, South Africa
- Authors: Tikwayo, Sizwe Edward
- Date: 2016
- Subjects: Ryegrasses -- Varieties -- South Africa -- Eastern Cape Ryegrasses -- Irrigation -- South Africa -- Eastern Cape Biomass energy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1796 , vital:27560
- Description: The study aims to evaluate the biomass production and nutrient content and silage quality of perennial ryegrass (Lolium perenne (L)), cocksfoot (Dactylis glomerata (L)) and tall fescue (Festuca arundinacea (Schreb)). Six varieties were used, two for each species. A completely randomized block designed replicated three times was conducted at University of Fort Hare Research Farm during 2014-2015 growing season. The plots were harvested at four-week interval (post emergency) for one year. Biomass yields were measured for fresh forage and dry matter yield. Duplicated samples were then dried, milled and analyzed for chemical and mineral composition (CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe) for only winter season. In addition the grasses were ensiled and the silage was analyzed for its fermentation parameters and nutrient content (lactic acid, pH, DM, CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe). Biomass results showed significant differences (P < 0.05) between season and varieties. On average Tall fescue varieties Jessup (13741.67 FM kg/ha), Alix (12007.78 FM kg/ ha) and Ryegrass varieties Samson (11597.22 FM kg/ha) and Nui (10591.67 FM kg/ha) had the highest fresh biomass yield. Similarly, Tall fescue varieties Jessup (2833.06 DM kg/ha) and Alix (2708.3 DM kg/ ha) and Ryegrass varieties Samson (2169.44 DM kg/ha) and Nui (2169.67 kg/ha) had the highest dry biomass yield. Throughout the year the average biomass yield was significantly different among species (P< 0.05). During summer and autumn Tall fescue varieties Jessup and Alix gave the highest dry matter yields of 3855.5 to 1977.8 DM kg/ha, and 3877.8 to 1900 DM kg/ha, respectively, and followed by Cocksfoot 2400 DM kg/ha. Ryegrass had the highest dry matter biomass yield in winter (2975 DM kg/ha) and the least in summer (977.75 DM kg/ha). There were no significant (P>0.05) differences on the chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe) of the six varieties. The grass silage results showed significant differences (P< 0.05) among the six varieties for moisture content. Perennial ryegrass variety Nui (66.76 percent) had low moisture content than the other grass silages. The different varieties had no significant effects (P>0.05) on chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe). It is concluded that the biomass production of the six varieties of three grass species was different throughout the year under irrigation hence Ryegrass and Tall fescue are recommended for dairy farmers in the region for all seasons. It can be concluded that there is no difference with respect to fermentation characteristics and nutrient content among the varieties of the grass species.
- Full Text:
- Date Issued: 2016
- Authors: Tikwayo, Sizwe Edward
- Date: 2016
- Subjects: Ryegrasses -- Varieties -- South Africa -- Eastern Cape Ryegrasses -- Irrigation -- South Africa -- Eastern Cape Biomass energy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/1796 , vital:27560
- Description: The study aims to evaluate the biomass production and nutrient content and silage quality of perennial ryegrass (Lolium perenne (L)), cocksfoot (Dactylis glomerata (L)) and tall fescue (Festuca arundinacea (Schreb)). Six varieties were used, two for each species. A completely randomized block designed replicated three times was conducted at University of Fort Hare Research Farm during 2014-2015 growing season. The plots were harvested at four-week interval (post emergency) for one year. Biomass yields were measured for fresh forage and dry matter yield. Duplicated samples were then dried, milled and analyzed for chemical and mineral composition (CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe) for only winter season. In addition the grasses were ensiled and the silage was analyzed for its fermentation parameters and nutrient content (lactic acid, pH, DM, CP, NDF, ADF, and ash, Ca, P, K, Na, Mn, Cu, Zn and Fe). Biomass results showed significant differences (P < 0.05) between season and varieties. On average Tall fescue varieties Jessup (13741.67 FM kg/ha), Alix (12007.78 FM kg/ ha) and Ryegrass varieties Samson (11597.22 FM kg/ha) and Nui (10591.67 FM kg/ha) had the highest fresh biomass yield. Similarly, Tall fescue varieties Jessup (2833.06 DM kg/ha) and Alix (2708.3 DM kg/ ha) and Ryegrass varieties Samson (2169.44 DM kg/ha) and Nui (2169.67 kg/ha) had the highest dry biomass yield. Throughout the year the average biomass yield was significantly different among species (P< 0.05). During summer and autumn Tall fescue varieties Jessup and Alix gave the highest dry matter yields of 3855.5 to 1977.8 DM kg/ha, and 3877.8 to 1900 DM kg/ha, respectively, and followed by Cocksfoot 2400 DM kg/ha. Ryegrass had the highest dry matter biomass yield in winter (2975 DM kg/ha) and the least in summer (977.75 DM kg/ha). There were no significant (P>0.05) differences on the chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe) of the six varieties. The grass silage results showed significant differences (P< 0.05) among the six varieties for moisture content. Perennial ryegrass variety Nui (66.76 percent) had low moisture content than the other grass silages. The different varieties had no significant effects (P>0.05) on chemical composition (CP, NDF, ADF, and ash) and mineral composition (Ca, P, K, Na, Mn, Cu, Zn and Fe). It is concluded that the biomass production of the six varieties of three grass species was different throughout the year under irrigation hence Ryegrass and Tall fescue are recommended for dairy farmers in the region for all seasons. It can be concluded that there is no difference with respect to fermentation characteristics and nutrient content among the varieties of the grass species.
- Full Text:
- Date Issued: 2016
Do differences in personality traits affect how drivers experience music at different intensities?
- Authors: Tlhoaele, Kebaabetswe
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3695 , vital:20536
- Description: Various researchers have investigated contributing factors towards the number of acute traffic incidences in and around Southern Africa. Some of these contributing factors include: the skills component of the driver predominately attributed to driving experience as well as the behavioural component influenced by the driver’s natural predisposition, individual differences and personality traits. In order to manage these factors drivers have developed varying coping mechanisms. One of these coping mechanisms is listening to music while driving, which is readily available in most cars and extensively used predominately during long duration driving. Listening to music neither increases one’s driving duration (as opposed to taking several breaks), nor does it interfere with the physical movements of driving (in the manner that eating and drinking may), but it might impact the concentration and attention of some drivers. This is based on the notion that music is assumed to impact arousal and cognitive ability. While there are several studies on the effect of music on driving performance and personality traits very few studies have looked at whether music has a positive or negative effect on driving performance based on differences in personality traits; and whether the extent of this effect might differ for different intensities of music? Consequently, this study aims to understand and determine the extent to which different personality traits predict the effect that listening to different music intensities has on driving performance. The impact of differing music conditions on the different personality traits used a repeated measures design and a between group design with respect to the personality traits with a sample size of (n=25)-16 females and 9 males-and their ages ranged between 19-35 years of age. The average age and standard deviation for this sample size was 22 years±2. A low-fidelity driving simulator task was utilised in order to provide a controllable, repeatable and a safe environment as compared to a real road situation. Personality was assessed using an online Big-Five Inventory scale (extraversion, agreeableness, conscientiousness, neuroticism, openness). All the different personality groups completed three conditions (45 minutes each) in a randomised order (without music, moderately loud music and loud music). Psychophysiological parameters i.e. heart rate frequency (HRF), heart rate variability (HRV) and eye movements (pupil diameter, eye speeds, fixation duration, blink frequency and blink duration) and driving performance were measured continuously. Subjective performance Multidimensional Driving Style Inventory was measured once-off prior to completion of the testing sessions, whilst the NASA-Task Load Index scale and Perceived control of participants were assessed after each condition. The expected outcomes revealed that music had an effect on objective driving performance (tracking deviation and reaction time) and psychophysiological measures only for participants of certain personality types while other personality types were unaffected by music. The subjective performance measures did not follow the same trend as objective performance measures. The conditions did not reveal an effect on driving performance, for most of the psychophysiological parameters and subjective measures. There was mainly a significant time on task effect and interactional effects on the psychophysiological measures (physiological and oculomotor) parameters at (p<0.05), but not on the subjective measures as anticipated. The study illustrated that the there are differences between personality traits. There was difficulty in the interpretation of the results based on the complexity of the findings for which each hypothesis was partially accepted. The research may establish practical implications for traffic safety campaigns in South Africa, as well as influence driving education for citizens. Assessing the personality trait would help to form an understanding as to which of the personality traits might be affected negatively from listening to music while driving and those that might benefit. Moreover, this study may assist motorists in understanding the implications of listening to music while driving as this may sometimes elicit risky driving behaviour and possibly cause an accident that may result in death.
- Full Text:
- Date Issued: 2016
- Authors: Tlhoaele, Kebaabetswe
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3695 , vital:20536
- Description: Various researchers have investigated contributing factors towards the number of acute traffic incidences in and around Southern Africa. Some of these contributing factors include: the skills component of the driver predominately attributed to driving experience as well as the behavioural component influenced by the driver’s natural predisposition, individual differences and personality traits. In order to manage these factors drivers have developed varying coping mechanisms. One of these coping mechanisms is listening to music while driving, which is readily available in most cars and extensively used predominately during long duration driving. Listening to music neither increases one’s driving duration (as opposed to taking several breaks), nor does it interfere with the physical movements of driving (in the manner that eating and drinking may), but it might impact the concentration and attention of some drivers. This is based on the notion that music is assumed to impact arousal and cognitive ability. While there are several studies on the effect of music on driving performance and personality traits very few studies have looked at whether music has a positive or negative effect on driving performance based on differences in personality traits; and whether the extent of this effect might differ for different intensities of music? Consequently, this study aims to understand and determine the extent to which different personality traits predict the effect that listening to different music intensities has on driving performance. The impact of differing music conditions on the different personality traits used a repeated measures design and a between group design with respect to the personality traits with a sample size of (n=25)-16 females and 9 males-and their ages ranged between 19-35 years of age. The average age and standard deviation for this sample size was 22 years±2. A low-fidelity driving simulator task was utilised in order to provide a controllable, repeatable and a safe environment as compared to a real road situation. Personality was assessed using an online Big-Five Inventory scale (extraversion, agreeableness, conscientiousness, neuroticism, openness). All the different personality groups completed three conditions (45 minutes each) in a randomised order (without music, moderately loud music and loud music). Psychophysiological parameters i.e. heart rate frequency (HRF), heart rate variability (HRV) and eye movements (pupil diameter, eye speeds, fixation duration, blink frequency and blink duration) and driving performance were measured continuously. Subjective performance Multidimensional Driving Style Inventory was measured once-off prior to completion of the testing sessions, whilst the NASA-Task Load Index scale and Perceived control of participants were assessed after each condition. The expected outcomes revealed that music had an effect on objective driving performance (tracking deviation and reaction time) and psychophysiological measures only for participants of certain personality types while other personality types were unaffected by music. The subjective performance measures did not follow the same trend as objective performance measures. The conditions did not reveal an effect on driving performance, for most of the psychophysiological parameters and subjective measures. There was mainly a significant time on task effect and interactional effects on the psychophysiological measures (physiological and oculomotor) parameters at (p<0.05), but not on the subjective measures as anticipated. The study illustrated that the there are differences between personality traits. There was difficulty in the interpretation of the results based on the complexity of the findings for which each hypothesis was partially accepted. The research may establish practical implications for traffic safety campaigns in South Africa, as well as influence driving education for citizens. Assessing the personality trait would help to form an understanding as to which of the personality traits might be affected negatively from listening to music while driving and those that might benefit. Moreover, this study may assist motorists in understanding the implications of listening to music while driving as this may sometimes elicit risky driving behaviour and possibly cause an accident that may result in death.
- Full Text:
- Date Issued: 2016
Evaluating farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients in Sheshegu communal rangelands of the Eastern Cape, South Africa
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
- Authors: Tokozwayo, Sive
- Date: 2016
- Subjects: Range management -- South Africa -- Eastern Cape Brush -- Control -- South Africa -- Eastern Cape Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2733 , vital:28066
- Description: Communal rangelands occupy 13 percent of the agricultural land in South Africa, and these rangelands serve as a source of feed to livestock. These areas are threatened by bush encroachment due to poor rangeland management. This study was conducted in Alice (Sheshegu communal area) and the objective was to assess farmers' perceptions and the impact of bush encroachment on herbaceous vegetation and soil nutrients. Structured questionnaires were used to assess indigenous knowledge of communal farmers on the impact of bush encroachment on rangelands. Fourty (40) respondents from households who owned livestock were randomly selected and interviewed at Sheshegu village. About 89 percent of communal farmers perceived that change of their grasslands to encroached savannas was caused by unreliable rainfall, prolonged drought, and poor rangeland management. Rangeland assessment was performed at four sites (Scattered, Moderate, Mixed and Dense bushland. 100mx50m were demarcated per site, and four 100m transects were laid parallel to each other, 30m apart. The step point method was used to determine both species composition and basal cover. Biomass production was determined by harvesting forage within randomly-paced a 0.25m2 quadrats. Aristada congesta and Eragrostis obtuse were the most dominating grass species in dense, mixed and moderate bushland. Scattered bushland was dominated by Themeda triandra. Biomass production increases with increase in bush density and basal cover improved from winter to summer season. Increaser grass species increase with the increase in bush density, this indicated that the rangeland was poorly managed and palatable species were being replaced by less palatable ones. Species composition of woody plants was determined within a 200m2 belt transect in all sites. Maytenus polycantha, Aloe ferox, Erehia rigida and lucas capensis were the most dominant woody species in Mixed bushland while Acacia karroo was most dominated in Scattered, Moderate and Dense bushland. Woody density showed no significant differences (P> 0.05) between Dense, Mixed and Moderate bushland. Woody plant density in all these sites exceed 2500 plants/ha, which showed that the rangeland was encroached with woody plants. Soil nutrient content was determined for each site. Five samples of soil were collected per site to test the effect of bush encroachment on soil nutrient composition. The concentration of nitrogen and soil pH increased with increase in bush density, while that of potassium, phosphorous, magnesium, sodium and sulphur showed no significant differences (P>0.05) across all homogenous vegetation units. The study revealed that Sheshegu communal farmers are aware of both negative and positive effects of encroachment on their community, and also argue that the government is not willing to support communal farmers in the process of reducing the spread of bush encroachment. It was concluded that the concentration of nitrogen and soil pH increased with increasing bush density and that bush encroachment had negative effects on herbaceous species. It was recommended that communal farmers should be formulating rangeland rules and regulations to manage rangeland resources. Rangeland rules and regulations should be based on the management of livestock management during grazing and harvesting of rangeland resources. The harvesting of woody and good timing of application of fire can also reduce the spread of bush encroachment. Veld resting and rotational grazing can also improve fuel load which is required for burning of woody plants. Furthermore, Department of agriculture should also provide workshops or training to communal farmers use different approaches or cheap ways of reducing bush encroachment and conserving rangeland resources.
- Full Text:
- Date Issued: 2016
The contribution of smallholder agriculture production to food security in rural Zimbabwe : a case study of Masvingo Province
- Authors: Toringepi, Godfrey
- Date: 2016
- Subjects: Farms, Small -- Zimbabwe Agricultural productivity -- Zimbabwe Sustainable agriculture -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5598 , vital:29350
- Description: Agricultural development is back on the development agenda. Even though the smallholder farmers are in the majority and at the forefront in terms of food production and agriculture being the backbone of the economy of Zimbabwe, there is no clearly defined policy on smallholder agriculture in Zimbabwe. The food insecurity has remained a continuous challenge for the rural poor in Zimbabwe. This study investigated the contribution of smallholder agriculture to food security with particular reference to the Masvingo province. The study employed qualitative method of research entailing extensive review of literature as a method of data collection. The study utilized the modernisation theory and sustainable livelihoods framework to illustrate smallholder agriculture and food security nexus. The study revealed that smallholder agriculture is the best option for addressing food security since agriculture is considered the main livelihood strategy for small scale farmers in Zimbabwe. There is general scholarly consensus that the main cause of food insecurity in Zimbabwe is a decrease in smallholder agriculture productivity. The study revealed that poor infrastructure , limited access to credit, limited access to inputs, poor investment in human development, limited access to markets and harsh climatic conditions weaken the capacity of small scale farmers to improve food security. Key recommendations are that supportive institutions need to be put in place to strengthen the smallholder farmer’s capacity to improve food security in Zimbabwe.
- Full Text:
- Date Issued: 2016
- Authors: Toringepi, Godfrey
- Date: 2016
- Subjects: Farms, Small -- Zimbabwe Agricultural productivity -- Zimbabwe Sustainable agriculture -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5598 , vital:29350
- Description: Agricultural development is back on the development agenda. Even though the smallholder farmers are in the majority and at the forefront in terms of food production and agriculture being the backbone of the economy of Zimbabwe, there is no clearly defined policy on smallholder agriculture in Zimbabwe. The food insecurity has remained a continuous challenge for the rural poor in Zimbabwe. This study investigated the contribution of smallholder agriculture to food security with particular reference to the Masvingo province. The study employed qualitative method of research entailing extensive review of literature as a method of data collection. The study utilized the modernisation theory and sustainable livelihoods framework to illustrate smallholder agriculture and food security nexus. The study revealed that smallholder agriculture is the best option for addressing food security since agriculture is considered the main livelihood strategy for small scale farmers in Zimbabwe. There is general scholarly consensus that the main cause of food insecurity in Zimbabwe is a decrease in smallholder agriculture productivity. The study revealed that poor infrastructure , limited access to credit, limited access to inputs, poor investment in human development, limited access to markets and harsh climatic conditions weaken the capacity of small scale farmers to improve food security. Key recommendations are that supportive institutions need to be put in place to strengthen the smallholder farmer’s capacity to improve food security in Zimbabwe.
- Full Text:
- Date Issued: 2016
Effect of phosphorus application on dry matter yield and nutrient content of Mucuna Pruriens (L) in Alice
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016
- Authors: Tshwati, Nolubabalo
- Date: 2016
- Subjects: Legumes Phosphorus Fertilizers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12326 , vital:39253
- Description: The use of herbaceous legumes such as Mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve livestock productivity in the small holder farming sector of South Africa. The objective of the study was to investigate the effect of phosphorus fertilizer application (0, 20, 40 and 60 kg P/ha) on the dry matter yield and nutritive value of Mucuna pruriens. The study was conducted at University of Fort Hare Research farm in Alice, South Africa. The research design was a randomized complete block design with three replicates per treatment. Data collection included biomass production and nutrient content of Mucuna pruriens. The forage legume was harvested at flowering stage of growth and analysed for chemical composition. The results showed that with the application of 60 kg P/ha Mucuna had the highest (P < 0.05) fresh and dry matter yield of 19.58 kg/ha and 5.41 kg/ha, respectively compared to other treatments. However, all the other treatments differed from one another. Similarly, the fresh stem and leaf fractions yield and their dry matter yields showed the same trend with application of 60 kg P/ha having the greatest yield compared to the other treatments. Nevertheless, all the treatments differed (P<0.05) from one another with P0 having the least yields. The leaf to stem ratio did not show any significant (P>0.05) difference among all the treatments ranging from 1.44 to 1.62 in fresh forage and ranging from 1.31 to 1.50 in the dry forage. In terms of dry matter content, the control treatment had the highest dry matter content of 37.78percent, however, all the other treatments did not differ significantly (P < 0.05) from each other. There was no significant effect of P application (P > 0.05) in terms of ash, EE, ADF, CP, Ca, Mg, K, Na, P, Zn, Cu, Mn and Fe of the whole plant forage among the treatments. The application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the NDF (51.16percent) of the whole plant of Mucuna compared to the other treatments which did not differ (p>0.05) among themselves. Within the stem fraction there were no significant (P > 0.05) differences among the treatments for the ash, EE, ADF, NDF, and CP, hemicellulose, Ca, Mg, K, P, Zn, Cu, Mn and Fe contents. However, the application of 40 kg P/ha fertilizer significantly (P < 0.05) increased the Na (0.05percent) content of the Mucuna stem fraction. In the leaf fraction of Mucuna there was no significant (P > 0.05) differences in terms of ash, EE, ADF, NDF, CP, hemicellulose, Ca, K, P, Zn, Cu, Mn and Fe among the treatments. However, the application of 20 kg P/ha fertilizer significantly (P < 0.05) increased the Mg (0.52percent) of the Mucuna leaves compared to the other treatments. Therefore the study has shown that increase in P application (60 kg P/ha) has no major effect in the nutrient content of Mucuna. Furthermore, it is recommended that Mucuna can be grown as a protein supplement, based on the CP content values that were recorded in this study and to provide maintenance requirements for ruminants. It was therefore concluded that phosphorus fertilization particularly 60 kg P/ha is necessary and required for optimum growth of Mucuna pruriens in order to increase forage yield. Based on the nutrient content result it was concluded that there was no effect of P fertilizer application levels on the nutrient content of Mucuna pruriens in Alice.
- Full Text:
- Date Issued: 2016