Assessing invasive alien aquatic plant species, phytoremediation effects using biological indicators in the Swartkops River system
- Authors: Tshithukhe, Getrude
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa -- Eastern Cape , Alien plants -- Biological control -- South Africa -- Eastern Cape , Phytoremediation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167665 , vital:41501
- Description: Pollution effluents in freshwater ecosystems are becoming increasingly ubiquitous as a result of cumulative anthropogenic activities, such as wastewater treatments works, and industrial, agricultural and mining activities. These activities are more noticeable in urban river atchments where there is greater human population densities and industrial developments. The ecological effects of anthropogenic activities on freshwater ecosystems include: excessive deposition of contaminants such as nutrients, pharmaceuticals, microplastics and other chemicals, which change physicochemical properties, causing a decline in aquatic biodiversity. These effects, impact negatively on the resilience of freshwater, making the systems vulnerable to invasion by alien aquatic plants. Ultimately, the loss of local biodiversity associated with the invasive alien aquatic plants (IAAP) results in a loss of some ecosystem goods and services. The Swartkops River system, Eastern Cape Province, drains most of the neighbouring formal and informal settlements, agricultural lands and industries, and hence is exposed to water pollution from human activities along the river catchment. Various water quality assessments are needed to evaluate the extent of pollutants and their impacts on the river ecosystem. Phytoremediation is one approach employed internationally for removing harmful nutrients and chemicals in freshwater ecosystems. Most studies measure the success of phytoremediation through measuring the reduction of contaminants in water or soil chemistry in mesocosm settings, which may not take into account all the important environmental factors that exist in the field. The present study assesses the phytoremediation potential of Pontederia (Eichhornia) crassipes and Salvinia molesta by evaluating water and sediment chemistry, periphyton and aquatic macroinvertebrate community recovery along seven field sites (excluding IAAP species mats sites) located upstream and downstream IAAP species mats on the Swartkops River between April and September 2018. Water and sediment samples were collected once monthly on ten seven field sites, including the IAAP species mat sites. Periphyton and aquatic macroinvertebrates were collected on seven sites, excluding the IAAP mat sites. Pontederia crassipes and S. molesta infestation in Swartkops River showed positive phytoremediation results and improved some water and sediment chemistry in the downstream treatments as compared to upstream treatments. Although there were some fluctuations with some variables, important water and sediment chemistry were reduced downstream. By contrast, biological assessment results did not show any response to the presence of IAAP species and phytoremediation. Periphyton and aquatic macroinvertebrates diversity and community assemblages were more influenced by water quality. Although IAAP species did provide improvement in water and sediments chemistry, multiple effluent point and non-point sources in Swartkops outpaced phytoremediation. Taxa evenness and relative taxa abundance showed significant differences between the upstream and downstream sites, however taxa richness and Shannon’s diversity showed no significant differences, indicating no relative recovery in biodiversity for either periphyton or aquatic macroinvertebrates. Similarly, the upstream and downstream sites showed similar periphyton and aquatic macroinvertebrates assemblages structure, all dominated by pollution tolerant taxa, thus indicating no functional diversity improvement down river; because of improvement in water chemistry downstream sites, it was expected that periphyton and aquatic macroinvertebrates assemblage structure would also improve at these downstream sites.It is possible that the phytoremediation process is outpaced by effluent discharges, given the multiple sources and distance between upstream and downstream mat sites. The study showed phytoremediation potential but the results were not indicated by biological indicators. A replica study conducted on a moderately disturbed river system is recommended to measure the success and recovery of biological indicators and assemblage composition following IAAP species phytoremediation; a moderately disturbed river compared to a largely disturbed river will broaden findings and look at differences for a wider application of phytoremediation.
- Full Text:
- Date Issued: 2020
- Authors: Tshithukhe, Getrude
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa -- Eastern Cape , Alien plants -- Biological control -- South Africa -- Eastern Cape , Phytoremediation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167665 , vital:41501
- Description: Pollution effluents in freshwater ecosystems are becoming increasingly ubiquitous as a result of cumulative anthropogenic activities, such as wastewater treatments works, and industrial, agricultural and mining activities. These activities are more noticeable in urban river atchments where there is greater human population densities and industrial developments. The ecological effects of anthropogenic activities on freshwater ecosystems include: excessive deposition of contaminants such as nutrients, pharmaceuticals, microplastics and other chemicals, which change physicochemical properties, causing a decline in aquatic biodiversity. These effects, impact negatively on the resilience of freshwater, making the systems vulnerable to invasion by alien aquatic plants. Ultimately, the loss of local biodiversity associated with the invasive alien aquatic plants (IAAP) results in a loss of some ecosystem goods and services. The Swartkops River system, Eastern Cape Province, drains most of the neighbouring formal and informal settlements, agricultural lands and industries, and hence is exposed to water pollution from human activities along the river catchment. Various water quality assessments are needed to evaluate the extent of pollutants and their impacts on the river ecosystem. Phytoremediation is one approach employed internationally for removing harmful nutrients and chemicals in freshwater ecosystems. Most studies measure the success of phytoremediation through measuring the reduction of contaminants in water or soil chemistry in mesocosm settings, which may not take into account all the important environmental factors that exist in the field. The present study assesses the phytoremediation potential of Pontederia (Eichhornia) crassipes and Salvinia molesta by evaluating water and sediment chemistry, periphyton and aquatic macroinvertebrate community recovery along seven field sites (excluding IAAP species mats sites) located upstream and downstream IAAP species mats on the Swartkops River between April and September 2018. Water and sediment samples were collected once monthly on ten seven field sites, including the IAAP species mat sites. Periphyton and aquatic macroinvertebrates were collected on seven sites, excluding the IAAP mat sites. Pontederia crassipes and S. molesta infestation in Swartkops River showed positive phytoremediation results and improved some water and sediment chemistry in the downstream treatments as compared to upstream treatments. Although there were some fluctuations with some variables, important water and sediment chemistry were reduced downstream. By contrast, biological assessment results did not show any response to the presence of IAAP species and phytoremediation. Periphyton and aquatic macroinvertebrates diversity and community assemblages were more influenced by water quality. Although IAAP species did provide improvement in water and sediments chemistry, multiple effluent point and non-point sources in Swartkops outpaced phytoremediation. Taxa evenness and relative taxa abundance showed significant differences between the upstream and downstream sites, however taxa richness and Shannon’s diversity showed no significant differences, indicating no relative recovery in biodiversity for either periphyton or aquatic macroinvertebrates. Similarly, the upstream and downstream sites showed similar periphyton and aquatic macroinvertebrates assemblages structure, all dominated by pollution tolerant taxa, thus indicating no functional diversity improvement down river; because of improvement in water chemistry downstream sites, it was expected that periphyton and aquatic macroinvertebrates assemblage structure would also improve at these downstream sites.It is possible that the phytoremediation process is outpaced by effluent discharges, given the multiple sources and distance between upstream and downstream mat sites. The study showed phytoremediation potential but the results were not indicated by biological indicators. A replica study conducted on a moderately disturbed river system is recommended to measure the success and recovery of biological indicators and assemblage composition following IAAP species phytoremediation; a moderately disturbed river compared to a largely disturbed river will broaden findings and look at differences for a wider application of phytoremediation.
- Full Text:
- Date Issued: 2020
Changes and continuities over time in the cultural significance of the Nyaminyami water spirit among the BaTonga people of northwestern Zimbabwe
- Authors: Matanzima, Joshua
- Date: 2019
- Subjects: Water spirits -- Zimbabwe , Tsonga (African people) -- Zimbabwe , Tsonga (African people) -- Zimbabwe -- Religion , Tsonga (African people) -- Zimbabwe -- Rites and ceremonies , Tsonga (African people) -- Zimbabwe -- Social life and customs , Mythology, Tsonga , Mythology, Zimbabwean , Nyaminyami (Spirit)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/94189 , vital:31015
- Description: Research attests that beliefs in water spirits are an integral part of cultures of many indigenous communities across the globe. These water spirits play significant political, religious and socio-economic roles for the people concerned. However, the functions of water spirits are not constant, but change over time, especially when the people believing in water spirits undergo drastic socio- economic processes of change. It is in this context that this thesis traces the cultural significance over time, of the Nyaminyami water spirit, among some BaTonga people, living in the immediate vicinity of the Kariba gorge area, in north-western Zimbabwe. While previous studies document the existence of beliefs in Nyaminyami, none of these has systematically traced the historical significance of Nyaminyami, in terms of changes and continuities over time. Thus, this thesis makes a valuable contribution to knowledge with regards to the history and religion of the BaTonga people. The thesis argues that Nyaminyami‘s cultural significance or functions evolved over time, due to numerous socio- economic and political processes of change. The major changes that significantly influenced the practices relating to Nyaminyami include colonialism, Kariba dam construction and resettlement, the migration after resettlement in the 1960s and 1970s, the independence of Zimbabwe, and the alienation of the Kariba waterscape from the BaTonga. To be able to arrive at specific findings and conclusions, the thesis is underpinned by theories about resettlement, approaches to water divinities, and theories of religion and social change. The thesis has five ethnographic chapters that focus on specific time periods, illustrating the major socio- economic changes of each epoch, and showing how these changes impacted upon practices and beliefs relating to Nyaminyami. The thesis also documents how Nyaminyami beliefs are variedly distributed along different social variables that include gender, age, income and geographical location. In order to achieve the findings presented, the thesis utilized ethnographic evidence obtained from semi- structured interviews, participant observation, anthropology of extraordinary experience, document review and archival research.
- Full Text:
- Date Issued: 2019
- Authors: Matanzima, Joshua
- Date: 2019
- Subjects: Water spirits -- Zimbabwe , Tsonga (African people) -- Zimbabwe , Tsonga (African people) -- Zimbabwe -- Religion , Tsonga (African people) -- Zimbabwe -- Rites and ceremonies , Tsonga (African people) -- Zimbabwe -- Social life and customs , Mythology, Tsonga , Mythology, Zimbabwean , Nyaminyami (Spirit)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/94189 , vital:31015
- Description: Research attests that beliefs in water spirits are an integral part of cultures of many indigenous communities across the globe. These water spirits play significant political, religious and socio-economic roles for the people concerned. However, the functions of water spirits are not constant, but change over time, especially when the people believing in water spirits undergo drastic socio- economic processes of change. It is in this context that this thesis traces the cultural significance over time, of the Nyaminyami water spirit, among some BaTonga people, living in the immediate vicinity of the Kariba gorge area, in north-western Zimbabwe. While previous studies document the existence of beliefs in Nyaminyami, none of these has systematically traced the historical significance of Nyaminyami, in terms of changes and continuities over time. Thus, this thesis makes a valuable contribution to knowledge with regards to the history and religion of the BaTonga people. The thesis argues that Nyaminyami‘s cultural significance or functions evolved over time, due to numerous socio- economic and political processes of change. The major changes that significantly influenced the practices relating to Nyaminyami include colonialism, Kariba dam construction and resettlement, the migration after resettlement in the 1960s and 1970s, the independence of Zimbabwe, and the alienation of the Kariba waterscape from the BaTonga. To be able to arrive at specific findings and conclusions, the thesis is underpinned by theories about resettlement, approaches to water divinities, and theories of religion and social change. The thesis has five ethnographic chapters that focus on specific time periods, illustrating the major socio- economic changes of each epoch, and showing how these changes impacted upon practices and beliefs relating to Nyaminyami. The thesis also documents how Nyaminyami beliefs are variedly distributed along different social variables that include gender, age, income and geographical location. In order to achieve the findings presented, the thesis utilized ethnographic evidence obtained from semi- structured interviews, participant observation, anthropology of extraordinary experience, document review and archival research.
- Full Text:
- Date Issued: 2019
The role of Information and Communication Technology in developing entrepreneurial skills in marginalised communities: the case of Grahamstown
- Authors: Mabika, Vinia Ruvimbo
- Date: 2019
- Subjects: Occupational training -- South Africa , Entrepreneurship -- South Africa , Vocational education -- South Africa , Information technology -- Study and teaching -- South Africa , Businesspeople, Black -- South Africa -- Makhanda , Businesspeople -- South Africa -- Makhanda , Non-governmental organizations -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/94169 , vital:31012
- Description: A call to meet the Sustainable Development Goals by 2030 was made by the United Nations in 2015 after the expiry of the Millennium Development Goals. This has led to the need for youth entrepreneurship studies in marginalised communities that are burdened by poverty. The marginalised communities in South Africa, where most poor unemployed people live face numerous challenges. These range from a shortage of skilled people, inequality, poverty, poor infrastructure and lack of formal and informal skills development for communities. Employing information and communication technologies (ICTs) has the potential to improve socio-economic activities, aid comprehensive human development and empower communities. To ensure human development, provision of ICTs to communities should be accompanied by approaches and guidelines that can be used to empower them through entrepreneurship. This requires investigating how ICTs can lead to the empowerment of unemployed citizens within a community. Specifically, the types of tailored ICT skills that are needed to access such empowerment opportunities and are typically taught at skills development programmes (SDPs). An interpretivist, qualitative case study approach was employed during the investigation of four skills development programmes in Grahamstown (Eastern Cape). The participants included programme directors, managers, trainees who had become entrepreneurs after attending training and those who had not started a business yet. Semi-structured interviews were employed for data collection and thematic analysis was used to analyse the data; while making use of absorptive capacity theory (ACT) as a theoretical framework. The researcher sought to answer the following main question: How should ICT-based skills development programmes be applied to enhance entrepreneurial skills within marginalised communities? To answer this, the research contributes by proposing a guideline that can be implemented to address the skills shortage in Grahamstown. The first stage requires a community needs assessment, looking at the community members prior and related knowledge. Secondly, the SDPs should create a culture of learning by transforming participants’ mindsets through core programmes. Thirdly, the core programmes should be linked with ICT skills training. After training is completed, the SDPs and external world bodies should assist with follow up support courses. During all these stages monitoring and evaluation should be implemented, and all key stakeholders should be involved.
- Full Text:
- Date Issued: 2019
- Authors: Mabika, Vinia Ruvimbo
- Date: 2019
- Subjects: Occupational training -- South Africa , Entrepreneurship -- South Africa , Vocational education -- South Africa , Information technology -- Study and teaching -- South Africa , Businesspeople, Black -- South Africa -- Makhanda , Businesspeople -- South Africa -- Makhanda , Non-governmental organizations -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/94169 , vital:31012
- Description: A call to meet the Sustainable Development Goals by 2030 was made by the United Nations in 2015 after the expiry of the Millennium Development Goals. This has led to the need for youth entrepreneurship studies in marginalised communities that are burdened by poverty. The marginalised communities in South Africa, where most poor unemployed people live face numerous challenges. These range from a shortage of skilled people, inequality, poverty, poor infrastructure and lack of formal and informal skills development for communities. Employing information and communication technologies (ICTs) has the potential to improve socio-economic activities, aid comprehensive human development and empower communities. To ensure human development, provision of ICTs to communities should be accompanied by approaches and guidelines that can be used to empower them through entrepreneurship. This requires investigating how ICTs can lead to the empowerment of unemployed citizens within a community. Specifically, the types of tailored ICT skills that are needed to access such empowerment opportunities and are typically taught at skills development programmes (SDPs). An interpretivist, qualitative case study approach was employed during the investigation of four skills development programmes in Grahamstown (Eastern Cape). The participants included programme directors, managers, trainees who had become entrepreneurs after attending training and those who had not started a business yet. Semi-structured interviews were employed for data collection and thematic analysis was used to analyse the data; while making use of absorptive capacity theory (ACT) as a theoretical framework. The researcher sought to answer the following main question: How should ICT-based skills development programmes be applied to enhance entrepreneurial skills within marginalised communities? To answer this, the research contributes by proposing a guideline that can be implemented to address the skills shortage in Grahamstown. The first stage requires a community needs assessment, looking at the community members prior and related knowledge. Secondly, the SDPs should create a culture of learning by transforming participants’ mindsets through core programmes. Thirdly, the core programmes should be linked with ICT skills training. After training is completed, the SDPs and external world bodies should assist with follow up support courses. During all these stages monitoring and evaluation should be implemented, and all key stakeholders should be involved.
- Full Text:
- Date Issued: 2019
Investigating herbivory and plant origin on tall-statured grasses in South Africa
- Authors: Canavan, Kim
- Date: 2017
- Subjects: Insects as biological pest control agents -- South Africa , Arundo donax , Giant reed -- South Africa , Giant reed -- Biological control -- South Africa , Phragmites australis , Phragmites mauritianus , Phragmites , Tetramesa romana , Biological invasions -- South Africa , Wasps -- Host plants , Wasps -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/6147 , vital:21051
- Description: South African riparian zones have been heavily degraded through anthropogenic activities such as dam construction and extraction of water for irrigation, which has resulted in a loss of ecosystem services and functioning. A consequence of such disturbances to riparian areas is in their susceptibility to invasive alien species (IAS). One such IAS is the giant reed, Arundo donax L. (Poaceae), introduced to South Africa in the 1700s largely for erosion control. Arundo donax has since greatly expanded in the country and is now one of the most abundant IAS. Arundo donax has been found to displace native vegetation and in South Africa this will most likely lead to the displacement of the native tall-statured grasses, Phragmites australis (Cav.) Trin. ex Steud. and Phragmites mauritianus Kunth. This study aimed to enhance our understanding of the tall-statured grasses A. donax, P. australis and P. mauritianus to better manage them in riparian areas. For A. donax, biological control is seen as the most viable option to control stands in the long-term. However, before such a programme is put in place, it is important to first collect baseline data that can be used to guide the direction of the biological control project in South Africa. For the Phragmites spp., despite being a dominant vegetative type in riparian areas, very little is known about their status in South Africa. Furthermore, there have been increasing reports of both Phragmites species having an expansion of their range and abundance. In North America, there has been a similar trend of reed expansion and through molecular work it was determined that a cryptic invasion has occurred with the introduction of an invasive non-native haplotype from Europe. It is therefore unknown if Phragmites spp. populations are expanding due to anthropogenic activities or due to a cryptic invasion. To address these shortfalls in knowledge the study investigated the tall-statured grasses in two parts; firstly, molecular techniques are used to explore the plant origin and genetic diversity of A. donax, P. australis and P. mauritianus and secondly using the Enemy Release Hypothesis as a framework, herbivore assemblages for each reed was determined across their distribution in South Africa. Molecular-techniques determined that both P. australis and P. mauritianus had only one haplotype - known as haplotype K and haplotype V respectively, across their distribution. For P. australis, haplotype K shares a close connection with populations from a Mediterranean lineage and this was further confirmed with a shared grass-waxy band. The direction and timing of genetic exchange between the two regions could not be ascertained and thus still remains unknown. Microsatellite analysis determined that both Phragmites spp. had a high genetic diversity compared to worldwide lineages. With no evidence of any cryptic invasions of haplotypes from other regions, both Phragmites spp. populations are likely to be native to South Africa. For A. donax all populations across South Africa were determined to be haplotype M1; a cosmopolitan haplotype that has an ancient native range in Afghanistan and Pakistan (Indus Valley). Populations were found to have no genetic diversity and thus can be considered one clone. A pre-introductory survey determined a list of herbivores associated with each tall- statured grass. For A. donax, a total of seven herbivores were found. Of these, one herbivore, a galling wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae) was found to be highly abundant and widely distributed in South Africa. Tetramesa romana is already a biological control agent in North America and thus is likely exerting some pressure on A. donax populations in South Africa. For both Phragmites spp. a total of ten herbivores were found, although having higher species richness compared to A. donax, when compared to other regions, these native species have a relatively low species richness. Providing baseline data on plant origin, genetic diversity and herbivory on A. donax, P. australis and P. mauritianus has provided important information on managing these species in riparian ecosystems in South Africa. For the Phragmites spp. with no evidence of any cryptic invasions, it is recommended that reed stands continue to be managed as native species. Phragmites spp. are important dominant vegetative species and thus should be protected; however, if reed stands become expansive, control methods can be put in place to focus on managing spread and abundance. For A. donax, this study was able to provide pivotal information in guiding the biological control programme. By determining the ancient lineage of South African populations, research can be focused in this area to find potential biological control agents. Lastly, the pre-introductory survey determined that a biological control agent, T. romana was already established with an unknown introduction and also highlighted potential plant parts that should be targeted. In particular, no rhizome feeding herbivores were found in South Africa and therefore this highlights an important niche that should be explored in biological control agents.
- Full Text:
- Date Issued: 2017
- Authors: Canavan, Kim
- Date: 2017
- Subjects: Insects as biological pest control agents -- South Africa , Arundo donax , Giant reed -- South Africa , Giant reed -- Biological control -- South Africa , Phragmites australis , Phragmites mauritianus , Phragmites , Tetramesa romana , Biological invasions -- South Africa , Wasps -- Host plants , Wasps -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/6147 , vital:21051
- Description: South African riparian zones have been heavily degraded through anthropogenic activities such as dam construction and extraction of water for irrigation, which has resulted in a loss of ecosystem services and functioning. A consequence of such disturbances to riparian areas is in their susceptibility to invasive alien species (IAS). One such IAS is the giant reed, Arundo donax L. (Poaceae), introduced to South Africa in the 1700s largely for erosion control. Arundo donax has since greatly expanded in the country and is now one of the most abundant IAS. Arundo donax has been found to displace native vegetation and in South Africa this will most likely lead to the displacement of the native tall-statured grasses, Phragmites australis (Cav.) Trin. ex Steud. and Phragmites mauritianus Kunth. This study aimed to enhance our understanding of the tall-statured grasses A. donax, P. australis and P. mauritianus to better manage them in riparian areas. For A. donax, biological control is seen as the most viable option to control stands in the long-term. However, before such a programme is put in place, it is important to first collect baseline data that can be used to guide the direction of the biological control project in South Africa. For the Phragmites spp., despite being a dominant vegetative type in riparian areas, very little is known about their status in South Africa. Furthermore, there have been increasing reports of both Phragmites species having an expansion of their range and abundance. In North America, there has been a similar trend of reed expansion and through molecular work it was determined that a cryptic invasion has occurred with the introduction of an invasive non-native haplotype from Europe. It is therefore unknown if Phragmites spp. populations are expanding due to anthropogenic activities or due to a cryptic invasion. To address these shortfalls in knowledge the study investigated the tall-statured grasses in two parts; firstly, molecular techniques are used to explore the plant origin and genetic diversity of A. donax, P. australis and P. mauritianus and secondly using the Enemy Release Hypothesis as a framework, herbivore assemblages for each reed was determined across their distribution in South Africa. Molecular-techniques determined that both P. australis and P. mauritianus had only one haplotype - known as haplotype K and haplotype V respectively, across their distribution. For P. australis, haplotype K shares a close connection with populations from a Mediterranean lineage and this was further confirmed with a shared grass-waxy band. The direction and timing of genetic exchange between the two regions could not be ascertained and thus still remains unknown. Microsatellite analysis determined that both Phragmites spp. had a high genetic diversity compared to worldwide lineages. With no evidence of any cryptic invasions of haplotypes from other regions, both Phragmites spp. populations are likely to be native to South Africa. For A. donax all populations across South Africa were determined to be haplotype M1; a cosmopolitan haplotype that has an ancient native range in Afghanistan and Pakistan (Indus Valley). Populations were found to have no genetic diversity and thus can be considered one clone. A pre-introductory survey determined a list of herbivores associated with each tall- statured grass. For A. donax, a total of seven herbivores were found. Of these, one herbivore, a galling wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae) was found to be highly abundant and widely distributed in South Africa. Tetramesa romana is already a biological control agent in North America and thus is likely exerting some pressure on A. donax populations in South Africa. For both Phragmites spp. a total of ten herbivores were found, although having higher species richness compared to A. donax, when compared to other regions, these native species have a relatively low species richness. Providing baseline data on plant origin, genetic diversity and herbivory on A. donax, P. australis and P. mauritianus has provided important information on managing these species in riparian ecosystems in South Africa. For the Phragmites spp. with no evidence of any cryptic invasions, it is recommended that reed stands continue to be managed as native species. Phragmites spp. are important dominant vegetative species and thus should be protected; however, if reed stands become expansive, control methods can be put in place to focus on managing spread and abundance. For A. donax, this study was able to provide pivotal information in guiding the biological control programme. By determining the ancient lineage of South African populations, research can be focused in this area to find potential biological control agents. Lastly, the pre-introductory survey determined that a biological control agent, T. romana was already established with an unknown introduction and also highlighted potential plant parts that should be targeted. In particular, no rhizome feeding herbivores were found in South Africa and therefore this highlights an important niche that should be explored in biological control agents.
- Full Text:
- Date Issued: 2017
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