Combination of photodynamic antimicrobial chemotherapy and ciprofloxacin to combat S. aureus and E. coli resistant biofilms
- Openda, Yolande Ikala, Nyokong, Tebello
- Authors: Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360384 , vital:65084 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103142"
- Description: Photodynamic antimicrobial chemotherapy (PACT) coupled with an antibiotic, ciprofloxacin (CIP), was investigated using two indium metallated cationic photosensitizers, a porphyrin (1) and a phthalocyanine (2). Applying PACT followed by the antibiotic treatment led to a remarkable reduction in the biofilm cell survival of two antibiotic-resistant bacterial strains, S. aureus (Gram-positive) and E. coli (Gram-nenative). Treating both bacteria strains with PACT alone showed no significant activity at 32 µM with 15 min irradiation, while CIP alone exhibited a minimum biofilm inhibition concentration (MBIC) at 4 and 8 µg/mL on S. aureus and E. coli, respectively following 24 h incubation. The combined treatment resulted in the complete eradication of the matured biofilms with high log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively, at low concentrations. It was found that 15 min PACT irradiation of 8 µM of complexes (1 and 2) combined with 2 µg/mL of CIP have a 100% reduction of the resistant S. aureus biofilms. Whereas the total killing of E. coli was obtained when combining 8 µM of complex 1 and 16 µM of complex 2 both combined with 4 µg/mL of CIP.
- Full Text:
- Date Issued: 2023
- Authors: Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360384 , vital:65084 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103142"
- Description: Photodynamic antimicrobial chemotherapy (PACT) coupled with an antibiotic, ciprofloxacin (CIP), was investigated using two indium metallated cationic photosensitizers, a porphyrin (1) and a phthalocyanine (2). Applying PACT followed by the antibiotic treatment led to a remarkable reduction in the biofilm cell survival of two antibiotic-resistant bacterial strains, S. aureus (Gram-positive) and E. coli (Gram-nenative). Treating both bacteria strains with PACT alone showed no significant activity at 32 µM with 15 min irradiation, while CIP alone exhibited a minimum biofilm inhibition concentration (MBIC) at 4 and 8 µg/mL on S. aureus and E. coli, respectively following 24 h incubation. The combined treatment resulted in the complete eradication of the matured biofilms with high log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively, at low concentrations. It was found that 15 min PACT irradiation of 8 µM of complexes (1 and 2) combined with 2 µg/mL of CIP have a 100% reduction of the resistant S. aureus biofilms. Whereas the total killing of E. coli was obtained when combining 8 µM of complex 1 and 16 µM of complex 2 both combined with 4 µg/mL of CIP.
- Full Text:
- Date Issued: 2023
Contrasting effects of climate change on the invasion risk and biocontrol potential of the invasive Iris pseudacorus L. between Northern and Southern Hemisphere
- Minuti, Gianmarco, Coetzee, Julie A, Stiers, Iris
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
Declines in Livestock Numbers Accompany Cropping Deagrarianisation Processes in the Eastern Cape, South Africa
- Shackleton, Charlie M, Ntshudu, Monde
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
Development of a translation device for axiological-semantic density in political news articles: Wording and charging
- Siebörger, Ian, Adendorff, Ralph D
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385311 , vital:68006 , xlink:href="https://doi.org/10.1515/text-2020-0156"
- Description: The concept of axiological-semantic density from Legitimation Code Theory (LCT) is extremely helpful in analysing political knowledge-building, as it describes the strength of relations between various people, political stances and moral judgements, enabling these to be positioned in relation to each other. We present a multi-level translation device designed to identify strengths of axiological-semantic density in political news articles from the Daily Sun, South Africa’s most popular tabloid newspaper. This translation device was devised through analysis of selected texts from a corpus of 516 articles published between January and June 2015. It was developed through a collaborative process involving the first author and a team of student research assistants. The final translation device has five tools, of which two, the wording and charging tools, are described in this article, and then illustrated using an example analysis of a Daily Sun political news article. Both tools reveal insights into South African political discourses and ways in which axiological-semantic density can be enacted in future research. Making axiological-semantic density visible using such a translation device also has practical applications in assisting readers to understand the ways in which publications such as the Daily Sun position political parties, enabling them to engage more constructively in discussions on the country’s future.
- Full Text:
- Date Issued: 2023
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385311 , vital:68006 , xlink:href="https://doi.org/10.1515/text-2020-0156"
- Description: The concept of axiological-semantic density from Legitimation Code Theory (LCT) is extremely helpful in analysing political knowledge-building, as it describes the strength of relations between various people, political stances and moral judgements, enabling these to be positioned in relation to each other. We present a multi-level translation device designed to identify strengths of axiological-semantic density in political news articles from the Daily Sun, South Africa’s most popular tabloid newspaper. This translation device was devised through analysis of selected texts from a corpus of 516 articles published between January and June 2015. It was developed through a collaborative process involving the first author and a team of student research assistants. The final translation device has five tools, of which two, the wording and charging tools, are described in this article, and then illustrated using an example analysis of a Daily Sun political news article. Both tools reveal insights into South African political discourses and ways in which axiological-semantic density can be enacted in future research. Making axiological-semantic density visible using such a translation device also has practical applications in assisting readers to understand the ways in which publications such as the Daily Sun position political parties, enabling them to engage more constructively in discussions on the country’s future.
- Full Text:
- Date Issued: 2023
Distribution and impact of the native South African wasp, Megastigmus transvaalensis (Hussey, 1956)(Hymenoptera: Torymidae) on the invasive Schinus terebinthifolia Raddi (Anacardiaceae) in South Africa
- Mangenlele, Nwabisa L, Martin, Grant D
- Authors: Mangenlele, Nwabisa L , Martin, Grant D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416841 , vital:71390 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a12"
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a tree native to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis (Hussey, 1956) (Hymenoptera: Torymidae). The wasp’s native hosts are from the Searsia F.A. Barkley genus (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative Schinus molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis was found at nearly all the S. terebinthifolia populations in South Africa, but due to the limited number of predated seeds it is unlikely to reduce population sizes or curb the spread of the invasive alien tree in South Africa.
- Full Text:
- Date Issued: 2023
- Authors: Mangenlele, Nwabisa L , Martin, Grant D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416841 , vital:71390 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a12"
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a tree native to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis (Hussey, 1956) (Hymenoptera: Torymidae). The wasp’s native hosts are from the Searsia F.A. Barkley genus (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative Schinus molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis was found at nearly all the S. terebinthifolia populations in South Africa, but due to the limited number of predated seeds it is unlikely to reduce population sizes or curb the spread of the invasive alien tree in South Africa.
- Full Text:
- Date Issued: 2023
Diverse values of nature for sustainability
- Pascual, Unai, Balvanera, Patricia, Anderson, Christopher B, Chaplin-Kramer, Rebecca, Christie, Michael, González-Jiménez, David, Martin, Adrian, Raymond, Christopher M, Termansen, Mette, Vatn, Arild, Athayde, Simone, Baptiste, Brigitte, Barton, Davind N, Jacobs, Sander, Kelemen, Eszter, Kumar, Ritesh, Lazos, Elena, Mwampamba, Tuyeni H, Nakangu, Barbara, O’Farrell, Patrick, Subramanian, Suneetha M, van Noordwijk, Meine, Ahn, SoEun, Amaruzaman, Sacha, Amin, Ariane M, Arias-Arévalo, Paola, Arroyo-Robles, Gabriela, Cantú-Fernández, Mariana, Castro, Antonio J, Contreras, Victoria, de Vos, Alta, Dendoncker, Nicolas, Engel, Stefanie, Eser, Uta, Faith, Daniel P, Filyushkina, Anna, Ghazi, Houda, Gómez-Baggethun, Erik, Gould, Rachelle K, Guibrunet, Louise, Gundimeda, Haripriya, Hahn, Thomas, Harmáčková, Zuzana V, Hernández-Blanco, Marcello, Horcea-Milcu, Andra-loana, Huambachano, Mariaelena, Wicher, Natalia L H, Aydın, Cem I, Islar, Mine, Koessler, Ann-Kathrin, Kenter, Jasper O, Kosmus, Marina, Lee, Heera, Leimona, Beria, Lele, Sharachchandra, Lenzi, Dominic, Lliso, Bosco, Mannetii, Lelani M, Merçon, Juliana, Monroy-Sais, Ana S, Mukherjee, Nibedita, Muraca, Barbara, Muradian, Roldan, Murali, Ranjini, Nelson, Sara H, Nemogá-Soto, Gabriel R, Ngouhouo-Poufoun, Jonas, Niamir, Aidin, Nuesiri, Emmanuel, Nyumba, Tobias O, Özkaynak, Begüm, Palomo, Ignacio, Pandit, Ram, Pawłowska-Mainville, Agnieszka, Porter-Bolland, Luciano, Quaas, Martin, Rode, Julian, Rozzi, Ricardo, Sachdeva, Sonya, Aibek, Samakov, Schaafsma, Marije, Sitas, Nadia, Ungar, Paula, Yiu, Evonne, Yoshida, Yuki, Zent, Eglee
- Authors: Pascual, Unai , Balvanera, Patricia , Anderson, Christopher B , Chaplin-Kramer, Rebecca , Christie, Michael , González-Jiménez, David , Martin, Adrian , Raymond, Christopher M , Termansen, Mette , Vatn, Arild , Athayde, Simone , Baptiste, Brigitte , Barton, Davind N , Jacobs, Sander , Kelemen, Eszter , Kumar, Ritesh , Lazos, Elena , Mwampamba, Tuyeni H , Nakangu, Barbara , O’Farrell, Patrick , Subramanian, Suneetha M , van Noordwijk, Meine , Ahn, SoEun , Amaruzaman, Sacha , Amin, Ariane M , Arias-Arévalo, Paola , Arroyo-Robles, Gabriela , Cantú-Fernández, Mariana , Castro, Antonio J , Contreras, Victoria , de Vos, Alta , Dendoncker, Nicolas , Engel, Stefanie , Eser, Uta , Faith, Daniel P , Filyushkina, Anna , Ghazi, Houda , Gómez-Baggethun, Erik , Gould, Rachelle K , Guibrunet, Louise , Gundimeda, Haripriya , Hahn, Thomas , Harmáčková, Zuzana V , Hernández-Blanco, Marcello , Horcea-Milcu, Andra-loana , Huambachano, Mariaelena , Wicher, Natalia L H , Aydın, Cem I , Islar, Mine , Koessler, Ann-Kathrin , Kenter, Jasper O , Kosmus, Marina , Lee, Heera , Leimona, Beria , Lele, Sharachchandra , Lenzi, Dominic , Lliso, Bosco , Mannetii, Lelani M , Merçon, Juliana , Monroy-Sais, Ana S , Mukherjee, Nibedita , Muraca, Barbara , Muradian, Roldan , Murali, Ranjini , Nelson, Sara H , Nemogá-Soto, Gabriel R , Ngouhouo-Poufoun, Jonas , Niamir, Aidin , Nuesiri, Emmanuel , Nyumba, Tobias O , Özkaynak, Begüm , Palomo, Ignacio , Pandit, Ram , Pawłowska-Mainville, Agnieszka , Porter-Bolland, Luciano , Quaas, Martin , Rode, Julian , Rozzi, Ricardo , Sachdeva, Sonya , Aibek, Samakov , Schaafsma, Marije , Sitas, Nadia , Ungar, Paula , Yiu, Evonne , Yoshida, Yuki , Zent, Eglee
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415612 , vital:71270 , xlink:href="https://doi.org/10.1038/s41586-023-06406-9"
- Description: Twenty-five years since foundational publications on valuing ecosystem services for human well-being, addressing the global biodiversity crisis still implies confronting barriers to incorporating nature’s diverse values into decision-making. These barriers include powerful interests supported by current norms and legal rules such as property rights, which determine whose values and which values of nature are acted on. A better understanding of how and why nature is (under)valued is more urgent than ever. Notwithstanding agreements to incorporate nature’s values into actions, including the Kunming-Montreal Global Biodiversity Framework (GBF) and the UN Sustainable Development Goals, predominant environmental and development policies still prioritize a subset of values, particularly those linked to markets, and ignore other ways people relate to and benefit from nature. Arguably, a ‘values crisis’ underpins the intertwined crises of biodiversity loss and climate change, pandemic emergence and socio-environmental injustices. On the basis of more than 50,000 scientifc publications, policy documents and Indigenous and local knowledge sources, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) assessed knowledge on nature’s diverse values and valuation methods to gain insights into their role in policymaking and fuller integration into decisions. Applying this evidence, combinations of values-centred approaches are proposed to improve valuation and address barriers to uptake, ultimately leveraging transformative changes towards more just (that is, fair treatment of people and nature, including inter- and intragenerational equity) and sustainable futures.
- Full Text:
- Date Issued: 2023
- Authors: Pascual, Unai , Balvanera, Patricia , Anderson, Christopher B , Chaplin-Kramer, Rebecca , Christie, Michael , González-Jiménez, David , Martin, Adrian , Raymond, Christopher M , Termansen, Mette , Vatn, Arild , Athayde, Simone , Baptiste, Brigitte , Barton, Davind N , Jacobs, Sander , Kelemen, Eszter , Kumar, Ritesh , Lazos, Elena , Mwampamba, Tuyeni H , Nakangu, Barbara , O’Farrell, Patrick , Subramanian, Suneetha M , van Noordwijk, Meine , Ahn, SoEun , Amaruzaman, Sacha , Amin, Ariane M , Arias-Arévalo, Paola , Arroyo-Robles, Gabriela , Cantú-Fernández, Mariana , Castro, Antonio J , Contreras, Victoria , de Vos, Alta , Dendoncker, Nicolas , Engel, Stefanie , Eser, Uta , Faith, Daniel P , Filyushkina, Anna , Ghazi, Houda , Gómez-Baggethun, Erik , Gould, Rachelle K , Guibrunet, Louise , Gundimeda, Haripriya , Hahn, Thomas , Harmáčková, Zuzana V , Hernández-Blanco, Marcello , Horcea-Milcu, Andra-loana , Huambachano, Mariaelena , Wicher, Natalia L H , Aydın, Cem I , Islar, Mine , Koessler, Ann-Kathrin , Kenter, Jasper O , Kosmus, Marina , Lee, Heera , Leimona, Beria , Lele, Sharachchandra , Lenzi, Dominic , Lliso, Bosco , Mannetii, Lelani M , Merçon, Juliana , Monroy-Sais, Ana S , Mukherjee, Nibedita , Muraca, Barbara , Muradian, Roldan , Murali, Ranjini , Nelson, Sara H , Nemogá-Soto, Gabriel R , Ngouhouo-Poufoun, Jonas , Niamir, Aidin , Nuesiri, Emmanuel , Nyumba, Tobias O , Özkaynak, Begüm , Palomo, Ignacio , Pandit, Ram , Pawłowska-Mainville, Agnieszka , Porter-Bolland, Luciano , Quaas, Martin , Rode, Julian , Rozzi, Ricardo , Sachdeva, Sonya , Aibek, Samakov , Schaafsma, Marije , Sitas, Nadia , Ungar, Paula , Yiu, Evonne , Yoshida, Yuki , Zent, Eglee
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415612 , vital:71270 , xlink:href="https://doi.org/10.1038/s41586-023-06406-9"
- Description: Twenty-five years since foundational publications on valuing ecosystem services for human well-being, addressing the global biodiversity crisis still implies confronting barriers to incorporating nature’s diverse values into decision-making. These barriers include powerful interests supported by current norms and legal rules such as property rights, which determine whose values and which values of nature are acted on. A better understanding of how and why nature is (under)valued is more urgent than ever. Notwithstanding agreements to incorporate nature’s values into actions, including the Kunming-Montreal Global Biodiversity Framework (GBF) and the UN Sustainable Development Goals, predominant environmental and development policies still prioritize a subset of values, particularly those linked to markets, and ignore other ways people relate to and benefit from nature. Arguably, a ‘values crisis’ underpins the intertwined crises of biodiversity loss and climate change, pandemic emergence and socio-environmental injustices. On the basis of more than 50,000 scientifc publications, policy documents and Indigenous and local knowledge sources, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) assessed knowledge on nature’s diverse values and valuation methods to gain insights into their role in policymaking and fuller integration into decisions. Applying this evidence, combinations of values-centred approaches are proposed to improve valuation and address barriers to uptake, ultimately leveraging transformative changes towards more just (that is, fair treatment of people and nature, including inter- and intragenerational equity) and sustainable futures.
- Full Text:
- Date Issued: 2023
Do thermal requirements of Dichrorampha odorata, a shoot-boring moth for the biological control of Chromolaena odorata, explain its failure to establish in South Africa?
- Nqayi, Slindile B, Zachariades, Costas, Coetzee, Julie A, Hill, Martin P, Chidwanyika, Frank, Uyi, Osariyekemwen O, McConnachie, Andrew J
- Authors: Nqayi, Slindile B , Zachariades, Costas , Coetzee, Julie A , Hill, Martin P , Chidwanyika, Frank , Uyi, Osariyekemwen O , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416851 , vital:71391 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a14"
- Description: Chromolaena odorata (L.) RM King and H Rob. (Asteraceae) has been subject to a biological control programme in South Africa for over three decades. A shoot-tip boring moth, Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), originating from Jamaica, was released as a biological control agent in 2013 but despite the release of substantial numbers of the insect, it has not established a permanent field population. Because climate incompatibility is a major constraint for classical biological control of invasive plants, and based on the differences in climate between Jamaica and South Africa and field observations at release sites, aspects of the thermal physiology of D. odorata were investigated to elucidate reasons for its failure to establish. Developmental time decreased with increasing temperatures ranging from 20 °C to 30 °C, with incomplete development for immature stages at 18 °C and 32 °C. The developmental threshold, t, was calculated as 8.45 °C with 872.4 degree-days required to complete development (K). A maximum of 6.5 generations per year was projected for D. odorata in South Africa, with the heavily infested eastern region of the country being the most eco-climatically suitable for establishment. The lower lethal temperature (LLT50) of larvae and adults was –4.5 and 1.8 °C, respectively. The upper lethal temperature (ULT50) for larvae was 39.6 °C whilst that of adults was 41.0 °C. Larvae thus had better cold tolerance compared to adults whereas adults had better heat tolerance compared to larvae. The critical thermal (CT) limits for adults were 3.4 ± 0.07 to 43.7 ± 0.12 °C. Acclimation at 20 °C for 7 days resulted in increased cold and heat tolerance with a CTmin and CTmax of 1.9 ± 0.06 and 44.4 ± 0.07 °C respectively, compared to the relative control, acclimated at 25 °C. Acclimation at 30 °C improved neither cold (CTmin: 5.9 ± 0.08 °C) nor heat tolerance (CTmax: 42.9 ± 0.10 °C). These results suggest that thermal requirements fall within field temperatures and are thus not the main constraining factor leading to poor establishment of D. odorata in South Africa.
- Full Text:
- Date Issued: 2023
- Authors: Nqayi, Slindile B , Zachariades, Costas , Coetzee, Julie A , Hill, Martin P , Chidwanyika, Frank , Uyi, Osariyekemwen O , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416851 , vital:71391 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a14"
- Description: Chromolaena odorata (L.) RM King and H Rob. (Asteraceae) has been subject to a biological control programme in South Africa for over three decades. A shoot-tip boring moth, Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), originating from Jamaica, was released as a biological control agent in 2013 but despite the release of substantial numbers of the insect, it has not established a permanent field population. Because climate incompatibility is a major constraint for classical biological control of invasive plants, and based on the differences in climate between Jamaica and South Africa and field observations at release sites, aspects of the thermal physiology of D. odorata were investigated to elucidate reasons for its failure to establish. Developmental time decreased with increasing temperatures ranging from 20 °C to 30 °C, with incomplete development for immature stages at 18 °C and 32 °C. The developmental threshold, t, was calculated as 8.45 °C with 872.4 degree-days required to complete development (K). A maximum of 6.5 generations per year was projected for D. odorata in South Africa, with the heavily infested eastern region of the country being the most eco-climatically suitable for establishment. The lower lethal temperature (LLT50) of larvae and adults was –4.5 and 1.8 °C, respectively. The upper lethal temperature (ULT50) for larvae was 39.6 °C whilst that of adults was 41.0 °C. Larvae thus had better cold tolerance compared to adults whereas adults had better heat tolerance compared to larvae. The critical thermal (CT) limits for adults were 3.4 ± 0.07 to 43.7 ± 0.12 °C. Acclimation at 20 °C for 7 days resulted in increased cold and heat tolerance with a CTmin and CTmax of 1.9 ± 0.06 and 44.4 ± 0.07 °C respectively, compared to the relative control, acclimated at 25 °C. Acclimation at 30 °C improved neither cold (CTmin: 5.9 ± 0.08 °C) nor heat tolerance (CTmax: 42.9 ± 0.10 °C). These results suggest that thermal requirements fall within field temperatures and are thus not the main constraining factor leading to poor establishment of D. odorata in South Africa.
- Full Text:
- Date Issued: 2023
Dual action of asymmetrical zinc (II) phthalocyanines conjugated to silver tungstate nanoparticles towards photodegradation of tetracycline and inactivation of Staphylococcus aureus bacteria
- Mgidlana, Sithi, Sen, Pinar, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
Electrocatalytic Behavior of Manganese and Cobalt Porphyrins Attached to Graphene Quantum Dots: Applied in the Oxidation of Hydrazine
- Jokazi, Mbulelo, Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Jokazi, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360411 , vital:65086 , xlink:href="https://doi.org/10.1002/elan.202200222"
- Description: Manganese and cobalt metalated 5, 10, 15-tris(aminophenyl)-20-(4-carboxyphenyl) porphyrins (ClMnTA3CPP and CoTA3CPP) were synthesized and attached to graphene quantum dots (GQDs) via π-π interaction and electrostatic interaction. The electrochemical oxidation of hydrazine was performed via cyclic voltammetry and chronoamperometry. The CoTA3CPP showed good electrocatalytic activity towards the oxidation of hydrazine in terms of catalytic rate constants and limits of detection (LoD). ClMnTA3CPP showed lower overpotential 0.60 V. The introduction of GQDs improved the electrocatalytic ability when combined with CoTA3CPP and ClMnTA3CPP with the lowest LoD (0.0025 mM CoTA3CPP–GQDs) followed by ClMnTA3CPP–GQDs with 0.0033 mM.
- Full Text:
- Date Issued: 2023
- Authors: Jokazi, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360411 , vital:65086 , xlink:href="https://doi.org/10.1002/elan.202200222"
- Description: Manganese and cobalt metalated 5, 10, 15-tris(aminophenyl)-20-(4-carboxyphenyl) porphyrins (ClMnTA3CPP and CoTA3CPP) were synthesized and attached to graphene quantum dots (GQDs) via π-π interaction and electrostatic interaction. The electrochemical oxidation of hydrazine was performed via cyclic voltammetry and chronoamperometry. The CoTA3CPP showed good electrocatalytic activity towards the oxidation of hydrazine in terms of catalytic rate constants and limits of detection (LoD). ClMnTA3CPP showed lower overpotential 0.60 V. The introduction of GQDs improved the electrocatalytic ability when combined with CoTA3CPP and ClMnTA3CPP with the lowest LoD (0.0025 mM CoTA3CPP–GQDs) followed by ClMnTA3CPP–GQDs with 0.0033 mM.
- Full Text:
- Date Issued: 2023
Evaluation of the antibacterial activity of gallic acid anchored phthalocyanine-doped silica nanoparticles towards Escherichia coli and Staphylococcus aureus biofilms and planktonic cells
- Magadla, Aviwe, Openda, Yolande Ikala, Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360424 , vital:65087 , xlink:href="https://doi.org/10.1016/j.pdpdt.2023.103520"
- Description: In this work, we have described the synthesis of phthalocyanine complexes Zn(II) tetrakis 4-(5-formylpyridin-2-yl)oxy) phthalocyanine (2), Zn(II) tetrakis-1 butyl 4-(2-(6- (tetra-phenoxy)pyridin-3-yl) vinyl)pyridin-1-ium phthalocyanine (3) and Zn(II) tetrakis 1 butyl 5-(2-(1-butylpyridin-1-ium-4-yl)vinyl)-2-(tetra-phenoxy)pyridin-1-ium phthalocyanine (4). The effect of a varying number of charges when the Pc complexes are alone or grafted in gallic acid (GA) tagged silica nanoparticles on photodynamic antimicrobial chemotherapy (PACT) is investigated toward Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) in both planktonic and biofilm forms. Complex 4, bearing a total of 8 cationic charges, displayed the highest activity with log CFU (colony forming units) values of 8.60 and 6.42 against E.coli and S.aureus biofilms, respectively. The surface stability of E.coli and S.aureus biofilms in the presence of 4 and its conjugate was analyzed using cyclic voltammetry. Scanning electron microscopy (SEM) and Raman spectra are also used to study the conformational and biochemical changes within biofilm upon subjecting them to PACT.
- Full Text:
- Date Issued: 2023
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360424 , vital:65087 , xlink:href="https://doi.org/10.1016/j.pdpdt.2023.103520"
- Description: In this work, we have described the synthesis of phthalocyanine complexes Zn(II) tetrakis 4-(5-formylpyridin-2-yl)oxy) phthalocyanine (2), Zn(II) tetrakis-1 butyl 4-(2-(6- (tetra-phenoxy)pyridin-3-yl) vinyl)pyridin-1-ium phthalocyanine (3) and Zn(II) tetrakis 1 butyl 5-(2-(1-butylpyridin-1-ium-4-yl)vinyl)-2-(tetra-phenoxy)pyridin-1-ium phthalocyanine (4). The effect of a varying number of charges when the Pc complexes are alone or grafted in gallic acid (GA) tagged silica nanoparticles on photodynamic antimicrobial chemotherapy (PACT) is investigated toward Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) in both planktonic and biofilm forms. Complex 4, bearing a total of 8 cationic charges, displayed the highest activity with log CFU (colony forming units) values of 8.60 and 6.42 against E.coli and S.aureus biofilms, respectively. The surface stability of E.coli and S.aureus biofilms in the presence of 4 and its conjugate was analyzed using cyclic voltammetry. Scanning electron microscopy (SEM) and Raman spectra are also used to study the conformational and biochemical changes within biofilm upon subjecting them to PACT.
- Full Text:
- Date Issued: 2023
Examining the implementation of the Department of Social Development’s fatherhood strategy by FAMSA
- Authors: Sishuba, Thozama Alicia
- Date: 2023
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27618 , vital:69320
- Description: This study aimed to exam the implementation of the Department of Social Development’s Fatherhood Strategy by Families South Africa (FAMSA) Eastern Cape. FAMSA is a non-profit organization providing vital services to people in families while providing them with psychosocial and emotional support. FAMSA has been in existence since 1954. To achieve this aim, the study’s objectives were underpinned by understanding the implementation of the Department of Social Development’s Fatherhood Strategy in Buffalo City Metro, establishing FAMSA’s response to the implementation of the Department of Social Development’s Fatherhood Strategy as well as exploring the challenges faced by FAMSA in implementing the Department of Social Development’s Fatherhood Strategy. A qualitative research methodology was implemented to gather information from FAMSA and DSD. Findings from literature revealed that the fatherhood strategy has been a concern worldwide evidenced by the high levels of father-child non-residency. Data from this study revealed that FAMSA had been implementing the programme effectively regardless of numerous challenges that include funding human resources. Conclusively, a lot must be done to advocate for fatherhood. Recommendations also point to the need for several interventions which need to be done in research, social work practice and also policy formulation and development. , Thesis (MA) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023
- Authors: Sishuba, Thozama Alicia
- Date: 2023
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27618 , vital:69320
- Description: This study aimed to exam the implementation of the Department of Social Development’s Fatherhood Strategy by Families South Africa (FAMSA) Eastern Cape. FAMSA is a non-profit organization providing vital services to people in families while providing them with psychosocial and emotional support. FAMSA has been in existence since 1954. To achieve this aim, the study’s objectives were underpinned by understanding the implementation of the Department of Social Development’s Fatherhood Strategy in Buffalo City Metro, establishing FAMSA’s response to the implementation of the Department of Social Development’s Fatherhood Strategy as well as exploring the challenges faced by FAMSA in implementing the Department of Social Development’s Fatherhood Strategy. A qualitative research methodology was implemented to gather information from FAMSA and DSD. Findings from literature revealed that the fatherhood strategy has been a concern worldwide evidenced by the high levels of father-child non-residency. Data from this study revealed that FAMSA had been implementing the programme effectively regardless of numerous challenges that include funding human resources. Conclusively, a lot must be done to advocate for fatherhood. Recommendations also point to the need for several interventions which need to be done in research, social work practice and also policy formulation and development. , Thesis (MA) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023
Fruits of the city: The nature, nurture and future of urban foraging
- Sardeshpande, Mallika, Shackleton, Charlie M
- Authors: Sardeshpande, Mallika , Shackleton, Charlie M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402259 , vital:69835 , xlink:href="https://doi.org/10.1002/pan3.10428"
- Description: Urban foraging is a global informal phenomenon which has been investigated in the Global North more than oth-er parts of the world. Characterising the nature of urban foraging in the Global South is imperative given the rapid urbanisation and sustainable development priorities in the region. In this study, we interviewed 80 urban forag-ers in four cities in the eastern coastal region of South Af-rica, with an aim to understand the nature of urban forag-ing in a developing nation context. We asked foragers about their initiation to and motivations for foraging, their logistics, yields and associated activities, descriptions of their foraging grounds, and if and how they had changed, and what they envisage as an ideal future for foraging.
- Full Text:
- Date Issued: 2023
- Authors: Sardeshpande, Mallika , Shackleton, Charlie M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402259 , vital:69835 , xlink:href="https://doi.org/10.1002/pan3.10428"
- Description: Urban foraging is a global informal phenomenon which has been investigated in the Global North more than oth-er parts of the world. Characterising the nature of urban foraging in the Global South is imperative given the rapid urbanisation and sustainable development priorities in the region. In this study, we interviewed 80 urban forag-ers in four cities in the eastern coastal region of South Af-rica, with an aim to understand the nature of urban forag-ing in a developing nation context. We asked foragers about their initiation to and motivations for foraging, their logistics, yields and associated activities, descriptions of their foraging grounds, and if and how they had changed, and what they envisage as an ideal future for foraging.
- Full Text:
- Date Issued: 2023
History matters: Societal acceptance of deep-sea mining and incipient conflicts in Papua New Guinea
- van Putten, Ingrid, Aswani, Shankar, Boonstra, W.J, De la Cruz-Modino, R, Das, Jewel, Glaser, Marion, Heck, Nadine, Narayan, Siddharth, Paytan, Adina, Selim, Samiya, Vave, Ron
- Authors: van Putten, Ingrid , Aswani, Shankar , Boonstra, W.J , De la Cruz-Modino, R , Das, Jewel , Glaser, Marion , Heck, Nadine , Narayan, Siddharth , Paytan, Adina , Selim, Samiya , Vave, Ron
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391453 , vital:68653 , xlink:href="https://doi.org/10.1007/s40152-023-00318-0"
- Description: New marine industries that develop and grow in response to the changing demand for their products have the potential to exert pressure on fragile marine environments. These emerging industries can benefit local communities but equally can have negative environmental and socio-cultural impacts. The development of new and emerging industries, like deep seabed mining (DSM), requires the acceptance and involvement of local communities. Yet, the history of marine exploitation is imbued with conflicts between industries and local communities. This paper presents a DSM case study in Papua New Guinea (PNG) to stimulate debate around the potential for conflict in the pursuit of resource extraction from the deep sea and the social and environmental harm that these extractions can cause. We do so by first presenting a timeline of local and extra-local events and enabling conditions that form the development background for the DSM Solwara 1 project in PNG. We then undertake a media narrative analysis to consider the contribution of aspects of social acceptability to this highly complex and multi-scale conflict. We find that the lack of (or a decrease in) social acceptability contributed to the conflict situation and ultimately the demise of the Solwara 1 project. Extra-locally, the initial development was positively framed around solutions for decarbonisation using new technology. Over time, actions by international NGOs, financial issues related to foreign companies, and asymmetry in the power balance between the Pacific Island nation and global businesses played a role in growing negative perceptions of acceptability. Historical experiences with prior environmental mining disasters, together with sea tenure governance challenges, and a lack of community and stakeholder acceptance also contributed to the demise of the project. Untangling and debating these complex interactions provides context and reasons for the tension between the lack of societal acceptance at a local scale and the perceived need for DSM products in the global North for innovative technologies and decarbonising societies. Better understanding these interactions and tensions can help emerging industries navigate a future blue economy.
- Full Text:
- Date Issued: 2023
- Authors: van Putten, Ingrid , Aswani, Shankar , Boonstra, W.J , De la Cruz-Modino, R , Das, Jewel , Glaser, Marion , Heck, Nadine , Narayan, Siddharth , Paytan, Adina , Selim, Samiya , Vave, Ron
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391453 , vital:68653 , xlink:href="https://doi.org/10.1007/s40152-023-00318-0"
- Description: New marine industries that develop and grow in response to the changing demand for their products have the potential to exert pressure on fragile marine environments. These emerging industries can benefit local communities but equally can have negative environmental and socio-cultural impacts. The development of new and emerging industries, like deep seabed mining (DSM), requires the acceptance and involvement of local communities. Yet, the history of marine exploitation is imbued with conflicts between industries and local communities. This paper presents a DSM case study in Papua New Guinea (PNG) to stimulate debate around the potential for conflict in the pursuit of resource extraction from the deep sea and the social and environmental harm that these extractions can cause. We do so by first presenting a timeline of local and extra-local events and enabling conditions that form the development background for the DSM Solwara 1 project in PNG. We then undertake a media narrative analysis to consider the contribution of aspects of social acceptability to this highly complex and multi-scale conflict. We find that the lack of (or a decrease in) social acceptability contributed to the conflict situation and ultimately the demise of the Solwara 1 project. Extra-locally, the initial development was positively framed around solutions for decarbonisation using new technology. Over time, actions by international NGOs, financial issues related to foreign companies, and asymmetry in the power balance between the Pacific Island nation and global businesses played a role in growing negative perceptions of acceptability. Historical experiences with prior environmental mining disasters, together with sea tenure governance challenges, and a lack of community and stakeholder acceptance also contributed to the demise of the project. Untangling and debating these complex interactions provides context and reasons for the tension between the lack of societal acceptance at a local scale and the perceived need for DSM products in the global North for innovative technologies and decarbonising societies. Better understanding these interactions and tensions can help emerging industries navigate a future blue economy.
- Full Text:
- Date Issued: 2023
Host-specificity testing of the leaf-feeding flea beetle, Phenrica guerini, a biological control agent for the invasive alien cactus, Pereskia aculeata
- Dixon, Elizabeth, Paterson, Iain D, Muskett, Philippa, McConnachie, Andrew
- Authors: Dixon, Elizabeth , Paterson, Iain D , Muskett, Philippa , McConnachie, Andrew
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417687 , vital:71478 , xlink:href="https://doi.org/10.1080/09583157.2023.2214342"
- Description: Pereskia aculeata Miller (Cactaceae) is an environmentally damaging invasive alien plant in South Africa and Australia. The flea-beetle, Phenrica guerini Bechyné (Coleoptera: Chrysomelidae), has been used in South Africa as a biological control agent against the plant for more than 30 years but updated host-specificity testing was required to determine its suitability as an agent in Australia. No-choice larval survival tests were conducted on 26 test plant species from 11 families, with survival to the adult stage only being recorded on the target weed, P. aculeata. No-choice oviposition testing with adult P. guerini was conducted on six test plant species. No adult feeding was recorded on any test plants and significantly more eggs were oviposited on P. aculeata (158.8 SE ± 21.4) than on Talinum caffrum (5.2 SE ± 5.2), which was the only test plant on which they oviposited. The adults survived on average 27 days longer on P. aculeata than on any test plant species. In a multiple-choice trial that included all three species that supported any larval feeding as well as P. aculeata, oviposition and feeding was only recorded on target weed. Phenrica guerini is suitably host specific for consideration in Australia as a biological control agent against P. aculeata.
- Full Text:
- Date Issued: 2023
- Authors: Dixon, Elizabeth , Paterson, Iain D , Muskett, Philippa , McConnachie, Andrew
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417687 , vital:71478 , xlink:href="https://doi.org/10.1080/09583157.2023.2214342"
- Description: Pereskia aculeata Miller (Cactaceae) is an environmentally damaging invasive alien plant in South Africa and Australia. The flea-beetle, Phenrica guerini Bechyné (Coleoptera: Chrysomelidae), has been used in South Africa as a biological control agent against the plant for more than 30 years but updated host-specificity testing was required to determine its suitability as an agent in Australia. No-choice larval survival tests were conducted on 26 test plant species from 11 families, with survival to the adult stage only being recorded on the target weed, P. aculeata. No-choice oviposition testing with adult P. guerini was conducted on six test plant species. No adult feeding was recorded on any test plants and significantly more eggs were oviposited on P. aculeata (158.8 SE ± 21.4) than on Talinum caffrum (5.2 SE ± 5.2), which was the only test plant on which they oviposited. The adults survived on average 27 days longer on P. aculeata than on any test plant species. In a multiple-choice trial that included all three species that supported any larval feeding as well as P. aculeata, oviposition and feeding was only recorded on target weed. Phenrica guerini is suitably host specific for consideration in Australia as a biological control agent against P. aculeata.
- Full Text:
- Date Issued: 2023
Host-specificity testing of the leaf-feeding flea beetle, Phenrica guerini, a biological control agent for the invasive alien cactus, Pereskia aculeata
- Dixon, Elizabeth, Paterson, Iain D, Muskett, Philippa, McConnachie, Andrew J
- Authors: Dixon, Elizabeth , Paterson, Iain D , Muskett, Philippa , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417713 , vital:71480 , xlink:href="https://doi.org/10.1080/09583157.2023.2214342"
- Description: Pereskia aculeata Miller (Cactaceae) is an environmentally damaging invasive alien plant in South Africa and Australia. The flea-beetle, Phenrica guerini Bechyné (Coleoptera: Chrysomelidae), has been used in South Africa as a biological control agent against the plant for more than 30 years but updated host-specificity testing was required to determine its suitability as an agent in Australia. No-choice larval survival tests were conducted on 26 test plant species from 11 families, with survival to the adult stage only being recorded on the target weed, P. aculeata. No-choice oviposition testing with adult P. guerini was conducted on six test plant species. No adult feeding was recorded on any test plants and significantly more eggs were oviposited on P. aculeata (158.8 SE ± 21.4) than on Talinum caffrum (5.2 SE ± 5.2), which was the only test plant on which they oviposited. The adults survived on average 27 days longer on P. aculeata than on any test plant species. In a multiple-choice trial that included all three species that supported any larval feeding as well as P. aculeata, oviposition and feeding was only recorded on target weed. Phenrica guerini is suitably host specific for consideration in Australia as a biological control agent against P. aculeata.
- Full Text:
- Date Issued: 2023
- Authors: Dixon, Elizabeth , Paterson, Iain D , Muskett, Philippa , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417713 , vital:71480 , xlink:href="https://doi.org/10.1080/09583157.2023.2214342"
- Description: Pereskia aculeata Miller (Cactaceae) is an environmentally damaging invasive alien plant in South Africa and Australia. The flea-beetle, Phenrica guerini Bechyné (Coleoptera: Chrysomelidae), has been used in South Africa as a biological control agent against the plant for more than 30 years but updated host-specificity testing was required to determine its suitability as an agent in Australia. No-choice larval survival tests were conducted on 26 test plant species from 11 families, with survival to the adult stage only being recorded on the target weed, P. aculeata. No-choice oviposition testing with adult P. guerini was conducted on six test plant species. No adult feeding was recorded on any test plants and significantly more eggs were oviposited on P. aculeata (158.8 SE ± 21.4) than on Talinum caffrum (5.2 SE ± 5.2), which was the only test plant on which they oviposited. The adults survived on average 27 days longer on P. aculeata than on any test plant species. In a multiple-choice trial that included all three species that supported any larval feeding as well as P. aculeata, oviposition and feeding was only recorded on target weed. Phenrica guerini is suitably host specific for consideration in Australia as a biological control agent against P. aculeata.
- Full Text:
- Date Issued: 2023
Impact of Access and Benefit Sharing implementation on biological control genetic resources
- Mason, Peter G, Barratt, Barbara I P, Mc Kay, Fernando, Klapwijk, Johannette N, Silvestri, Luciano C, Hill, Martin P, Hinz, Hariet L, Sheppard, Andy, Brodeur, Jacques, Vitorino, Marcello Diniz, Weyl, Philip S R, Hoelmer, Kim A
- Authors: Mason, Peter G , Barratt, Barbara I P , Mc Kay, Fernando , Klapwijk, Johannette N , Silvestri, Luciano C , Hill, Martin P , Hinz, Hariet L , Sheppard, Andy , Brodeur, Jacques , Vitorino, Marcello Diniz , Weyl, Philip S R , Hoelmer, Kim A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418013 , vital:71501 , xlink:href="https://doi.org/10.1007/s10526-023-10176-8"
- Description: The third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the use of genetic resources was further developed when the Nagoya Protocol on Access and Benefit Sharing came into effect in 2014. Interpretation of how this agreement is being implemented is wide-ranging and there are implications for biological control. A survey of biological control workers indicated that while some countries have facilitated access to biological control genetic resources, requirements in other countries have impeded biological control implementation. There was consensus that benefits to provider countries should be in the form of supporting local research communities. There was also agreement that the free use and exchange of biological control genetic resources has provided benefits to the global community, including to both providers and recipients of the agents. It is recommended that consideration of the free use and exchange principal should be a key element of Access and Benefit Sharing measures for the future.
- Full Text:
- Date Issued: 2023
- Authors: Mason, Peter G , Barratt, Barbara I P , Mc Kay, Fernando , Klapwijk, Johannette N , Silvestri, Luciano C , Hill, Martin P , Hinz, Hariet L , Sheppard, Andy , Brodeur, Jacques , Vitorino, Marcello Diniz , Weyl, Philip S R , Hoelmer, Kim A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418013 , vital:71501 , xlink:href="https://doi.org/10.1007/s10526-023-10176-8"
- Description: The third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the use of genetic resources was further developed when the Nagoya Protocol on Access and Benefit Sharing came into effect in 2014. Interpretation of how this agreement is being implemented is wide-ranging and there are implications for biological control. A survey of biological control workers indicated that while some countries have facilitated access to biological control genetic resources, requirements in other countries have impeded biological control implementation. There was consensus that benefits to provider countries should be in the form of supporting local research communities. There was also agreement that the free use and exchange of biological control genetic resources has provided benefits to the global community, including to both providers and recipients of the agents. It is recommended that consideration of the free use and exchange principal should be a key element of Access and Benefit Sharing measures for the future.
- Full Text:
- Date Issued: 2023
International agreement for the use and exchange of classical biological control genetic resources: a practical proposal
- Mason, Peter G, Mc Kay, Fernando, Silvestri, Luciano C, Hill, Martin P, Weyl, Philip S R, Hinz, Hariet L, Brodeur, Jacques, Vitorino, Marcello Diniz, Barratt, Barbara I P
- Authors: Mason, Peter G , Mc Kay, Fernando , Silvestri, Luciano C , Hill, Martin P , Weyl, Philip S R , Hinz, Hariet L , Brodeur, Jacques , Vitorino, Marcello Diniz , Barratt, Barbara I P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418025 , vital:71502 , xlink:href="https://doi.org/10.1007/s10526-023-10177-7"
- Description: The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.
- Full Text:
- Date Issued: 2023
- Authors: Mason, Peter G , Mc Kay, Fernando , Silvestri, Luciano C , Hill, Martin P , Weyl, Philip S R , Hinz, Hariet L , Brodeur, Jacques , Vitorino, Marcello Diniz , Barratt, Barbara I P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418025 , vital:71502 , xlink:href="https://doi.org/10.1007/s10526-023-10177-7"
- Description: The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.
- Full Text:
- Date Issued: 2023
Investigation into response of wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Know thy enemy: Investigating genetic contributions from putative parents of invasive Nymphaea mexicana hybrids in South Africa as part of efforts to develop biological control
- Reid, Megan K, Paterson, Iain D, Coetzee, Julie A, Gettys, Lyn A, Hill, Martin P
- Authors: Reid, Megan K , Paterson, Iain D , Coetzee, Julie A , Gettys, Lyn A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423540 , vital:72070 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105291"
- Description: Hybridisation of alien invasive plants complicates efforts to develop biological control, because variations in the genetic makeup of the target plant can impact the survival of host specific agents that have evolved adaptations specific to the original host. To maximise the likelihood of success in a biological control program, potential agents should therefore be collected from populations in the region of origin that are genetically similar to plants in the invaded range. Molecular markers are useful tools to understand genetic contributions in hybrid populations, especially where morphological differentiation is difficult. Nymphaea mexicana Zuccarini (Nymphaeaceae) is an invasive alien plant in South Africa that is being targeted for biological control, but hybrids with intermediate morphological traits are also present at several sites. In this study, ISSR (inter simple sequence repeats) and ITS (internal transcribed spacer) markers were used to determine which Nymphaea species are likely to be putative parents of these hybrids, and morphological characters were also investigated to determine if genetic and morphological traits matched. Two major hybrid groups were identified, with one group clustering with Nymphaea odorata Aiton and the other clustering with Nymphaea alba L. A third, smaller group clustered with Nymphaea tetragona Georgi, whereas the remaining samples clustered with pure N. mexicana from the native range. Morphological features agreed with deductions drawn from molecular data. These results allow us to focus efforts to find compatible biological control agents and better understand the complicated genetic structure of N. mexicana and Nymphaea hybrids in South Africa.
- Full Text:
- Date Issued: 2023
- Authors: Reid, Megan K , Paterson, Iain D , Coetzee, Julie A , Gettys, Lyn A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423540 , vital:72070 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105291"
- Description: Hybridisation of alien invasive plants complicates efforts to develop biological control, because variations in the genetic makeup of the target plant can impact the survival of host specific agents that have evolved adaptations specific to the original host. To maximise the likelihood of success in a biological control program, potential agents should therefore be collected from populations in the region of origin that are genetically similar to plants in the invaded range. Molecular markers are useful tools to understand genetic contributions in hybrid populations, especially where morphological differentiation is difficult. Nymphaea mexicana Zuccarini (Nymphaeaceae) is an invasive alien plant in South Africa that is being targeted for biological control, but hybrids with intermediate morphological traits are also present at several sites. In this study, ISSR (inter simple sequence repeats) and ITS (internal transcribed spacer) markers were used to determine which Nymphaea species are likely to be putative parents of these hybrids, and morphological characters were also investigated to determine if genetic and morphological traits matched. Two major hybrid groups were identified, with one group clustering with Nymphaea odorata Aiton and the other clustering with Nymphaea alba L. A third, smaller group clustered with Nymphaea tetragona Georgi, whereas the remaining samples clustered with pure N. mexicana from the native range. Morphological features agreed with deductions drawn from molecular data. These results allow us to focus efforts to find compatible biological control agents and better understand the complicated genetic structure of N. mexicana and Nymphaea hybrids in South Africa.
- Full Text:
- Date Issued: 2023
Local peoples’ knowledge and perceptions of Australian wattle (Acacia) species invasion, ecosystem services and disservices in grassland landscapes, South Africa
- Yapi, Thozamile S, Shackleton, Charlie M, Le Maitre, David C, Dziba, Luthando E
- Authors: Yapi, Thozamile S , Shackleton, Charlie M , Le Maitre, David C , Dziba, Luthando E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399791 , vital:69559 , xlink:href="https://doi.org/10.1080/26395916.2023.2177495"
- Description: Many alien tree species were introduced into grassland ecosystems in South Africa by the commercial forestry industry for paper and timber for furniture. Over decades some of these introduced species escaped into neighbouring farms and community land. Adult trees from these alien species now provide other ecosystem services, notably fuelwood. Depending on the spatio-temporal context, many of these species can also negatively affect ecosystem services. We collected interview data from commercial and communal farmers in the upper Umzimvubu catchment in South Africa to compare farmers’ knowledge and perceptions of invasive wattle species invasion and their associated ecosystem services and disservices. Fuelwood and fencing poles were the most common uses of wattle by commercial (83%; 67%) and communal (99%; 49%) farmers. On the other hand, the reduction of grass cover and loss of grazing land were the most commonly mentioned negative impacts of wattles by commercial (83%; 75%) and communal (92%; 80%) farmers. Although both groups recognise the importance of wattles in providing ecosystem services, most communal farmers perceived wattles to have more negative effects than benefits. The findings demonstrate that both farmer groups highly depend on ecosystem services and are affected by disservices of wattles. However, while large-scale commercial households favour the presence of wattles in the landscape, communal households prefer complete removal of the wattles from the landscape. This may be due to lack of locally available alternative options or inability to replace or purchase ecosystem services affected by wattles from other sources or markets like commercial farmers.
- Full Text:
- Date Issued: 2023
- Authors: Yapi, Thozamile S , Shackleton, Charlie M , Le Maitre, David C , Dziba, Luthando E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399791 , vital:69559 , xlink:href="https://doi.org/10.1080/26395916.2023.2177495"
- Description: Many alien tree species were introduced into grassland ecosystems in South Africa by the commercial forestry industry for paper and timber for furniture. Over decades some of these introduced species escaped into neighbouring farms and community land. Adult trees from these alien species now provide other ecosystem services, notably fuelwood. Depending on the spatio-temporal context, many of these species can also negatively affect ecosystem services. We collected interview data from commercial and communal farmers in the upper Umzimvubu catchment in South Africa to compare farmers’ knowledge and perceptions of invasive wattle species invasion and their associated ecosystem services and disservices. Fuelwood and fencing poles were the most common uses of wattle by commercial (83%; 67%) and communal (99%; 49%) farmers. On the other hand, the reduction of grass cover and loss of grazing land were the most commonly mentioned negative impacts of wattles by commercial (83%; 75%) and communal (92%; 80%) farmers. Although both groups recognise the importance of wattles in providing ecosystem services, most communal farmers perceived wattles to have more negative effects than benefits. The findings demonstrate that both farmer groups highly depend on ecosystem services and are affected by disservices of wattles. However, while large-scale commercial households favour the presence of wattles in the landscape, communal households prefer complete removal of the wattles from the landscape. This may be due to lack of locally available alternative options or inability to replace or purchase ecosystem services affected by wattles from other sources or markets like commercial farmers.
- Full Text:
- Date Issued: 2023