Enhanced nonlinear optical response of benzothiazole substituted ball-type phthalocyanines in the presence of metallic nanoparticles
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188149 , vital:44727 , xlink:href="https://doi.org/10.1016/j.optmat.2018.05.052"
- Description: The synthesis of zinc-zinc, gallium-gallium and indium-indium ball-type phthalocyanines (complexes 4, 5 and 6) and the surface assembly of the complexes onto metallic gold and silver nanoparticles are reported in this work. Furthermore, their photophysical and nonlinear optical dynamics were investigated. Decreases in the fluorescence quantum yields with a corresponding increase in the triplet quantum yields of the nanoconjugates in comparison to complexes 4, 5 and 6 alone were observed. The mechanism of strong reverse saturable absorption observed was found to be predominantly dependent on excited state absorption. The optical limiting thresholds range from 0.09 to 0.19 J/cm2. Enhanced triplet parameters and nonlinear optical responses were found when the complexes were conjugated to metallic nanoparticles.
- Full Text:
- Date Issued: 2018
Erasure: A challenge to Feminist and Queer research
- Authors: Marx, Jacqueline , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434210 , vital:73039 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_20
- Description: Anonymity and confidentiality feature prominently in research ethics guidelines. In this chapter we draw on examples from a research ethics application for a project involving women who had extricated themselves from relationships in which they had experienced intimate partner violence, and an ethnographic study of cross-dressing and drag, to illustrate the multiple ways in which identity masking can be put to work, both promoting and undermining what it means to do ethical research. We argue that the requirement for anonymity and confidentiality cannot be assessed without taking into account historicity and the sociopolitical contexts in which a study and its participants are located. The chapter concludes by giving consideration to the potential of a situated ethics approach and the implications for ethics review processes.
- Full Text:
- Date Issued: 2018
Ethics in critical research: Stories from the field
- Authors: Macleod, Catriona I , Marx, Jacqueline , Mnyaka, Phindezwa , Treharne, Gareth J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434223 , vital:73040 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_1
- Description: In this chapter we introduce the approaches to ethics in critical research applied throughout this handbook. Critical research questions who benefits from research and offers critiques rooted in postmodern and liberatory theories, including feminism, Marxism, and postcolonialism. Authors of chapters in the handbook explore ethical issues faced when conducting critical research through stories from the field across a range of methodologies, disciplines, and locations. The chapter overviews the four sections of the handbook and the ethical challenges associated with conducting critical research within the bureaucracy of ethics committees and other systems of governance, blurring the boundaries between researchers and participants/co-researchers, giving voice through research whilst applying anonymity or naming participants/co-researchers, and conducting research with various configurations of power between researchers and participants/co-researchers.
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- Date Issued: 2018
Ethics in transdisciplinary research: reflections on the implications of ‘Science with Society’
- Authors: Cockburn, Jessica J , Cundill, Georgina
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436187 , vital:73236 , ISBN 978-3-319-74721-7 , https://doi.org/10.1007/978-3-319-74721-7_6
- Description: Transdisciplinarity is a reflexive, participatory research approach that addresses societal problems by transcending the boundaries between science and society through knowledge co-production. Research ethics clearance procedures are of-ten out of step with such forms of engaged research. Through a case study of a transdisciplinary PhD, we share our experiences of the ethical challenges involved in research that takes place beyond the bounds of procedural ethics. Our research aims to co-produce knowledge on environmental stewardship. In this chapter we consider what strategies transdisciplinary scholars can employ to ensure they fulfil the requirements of ethical research in the absence of suitably aligned institutional processes, and what changes need to be made to research ethics clearance procedures to ensure they are able to account for transdisciplinary research.
- Full Text:
- Date Issued: 2018
Evaluating the efficacy of Hypogeococcus sp. as a biological control agent of the cactaceous weed Cereus jamacaru in South Africa
- Authors: Sutton, Guy F , Klein, H , Paterson, Iain D
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423350 , vital:72051 , xlink:href="https://doi.org/10.1007/s10526-018-9887-3"
- Description: We evaluated the efficacy of Hypogeococcus sp. (Hemiptera: Pseudococcidae) as a biological control agent of the cactaceous weed Cereus jamacaru De Candolle (Queen of the Night cactus) in South Africa. This weed has been described as being under complete biological control due to the action of Hypogeococcus sp., although no formal post-release evaluation had been conducted prior to this study. Biological control was associated with significant reductions in fruiting, plant survival and plant densities, while plant population age structures were negatively affected. Weed populations infected by Hypogeococcus sp. were typified by low or non-existent recruitment and are expected to diminish with time. Populations where Hypogeococcus sp. was absent displayed extensive recruitment, and are predicted to expand or self-replace, if left unchecked. These data indicate that Hypogeococcus sp. has a significant negative effect on C. jamacaru at the individual plant and population level, and given sufficient time provides complete biological control over this weed in South Africa.
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- Date Issued: 2018
Evaluation of the photophysicochemical properties and photodynamic therapy activity of nanoconjugates of zinc phthalocyanine linked to glutathione capped Au and Au3Ag1 nanoparticles
- Authors: Oluwole, David O , Manoto, Sello L , Malabi, Rudzani , Maphanga, Charles , Ombinda-Lemboumba, Saturnin , Mthunzi-Kufa, Patience , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237886 , vital:50563 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.11.019"
- Description: We report on the synthesis of glutathione capped gold (AuNPs–GSH) and gold–silver (Au3Ag1NPs–GSH) nanoparticles and their covalent attachment to Zn monocarboxyphenoxy phthalocyanine (1) via amide bond formation. The photophysicochemical properties and photodynamic therapy (PDT) activity of the complex and its nanoconjugates were assessed. The conjugates afforded improved triplet and singlet oxygen quantum yield as well as PDT activity (except for 1-Au3Ag1NPs which afforded decreased activity) in comparison to complex 1.
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- Date Issued: 2018
Evidence for a new regime shift between floating and submerged invasive plant dominance in South Africa
- Authors: Strange, Emily F , Hill, Martin P , Coetzee, Julie A
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423993 , vital:72114 , xlink:href="https://doi.org/10.1007/s10750-018-3506-2"
- Description: Classical biological control for the management of floating invasive plants has been highly successful in South Africa. However, restoring ecosystem services has been compromised by a new suite of submerged invasive plants. This study proposes that biological control of floating invasive macrophytes acts as a catalyst in a regime shift between floating and submerged invasive plant dominance. Regime shifts are large and sudden changes in the structure and functioning of ecosystems. The proposed shift is driven by the rapid decomposition of floating plants and subsequent increase in availability of nutrients and light. A mesocosm experiment explored the effect of biological control on floating Pistia stratiotes L. (Araceae) upon the growth of invasive submerged Egeria densa Planch. (Hydrocharitaceae), and native submerged plant species of the same family; Lagarosiphon major (Ridl.) Moss (Hydrocharitaceae). The results revealed a cascade effect of biological control of P. stratiotes on the availability of nitrogen, resulting in increased relative growth rates and invasive capacity for E. densa. In contrast, the native L. major could not compete with healthy or damaged P. stratiotes. These findings highlight the vulnerability of South African freshwater systems to submerged plant invasions and demonstrate the importance of a more holistic approach to invasive plant management.
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- Date Issued: 2018
Exploration and design of a synchronous message passing framework for a CPU-NPU heterogeneous architecture
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429537 , vital:72620 , https://ieeexplore.ieee.org/abstract/document/8425384
- Description: In this paper we present the development of a framework for communication between an NPU (network processing unit) and CPU through synchronous message passing that is compliant with the synchronous communication events of the CSP formalisms. This framework is designed to be used for passing generic information between application components operating on both architectures and is intended to operate in conjunction with existing datapaths present on the NPU which in turn are responsible for network traffic transmission. An investigation of different message passing topologies is covered before the proposed message passing fabric is presented. As a proof of concept, an initial implementation of the fabric is developed and tested to determine its viability and correctness. Through testing it is shown that the implemented framework operates as intended. However, it is noted the throughput of the exploratory implementation is not considered suitable for high-performance applications and further evaluation is required.
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- Date Issued: 2018
Exploring learning networks for homestead food gardening and smallholder farming
- Authors: Lotz-Sisitka, Heila
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182775 , vital:43873 , xlink:href="https://hdl.handle.net/10520/EJC-f09c3866c "
- Description: The Water Research Commission (WRC) is well known for its high quality knowledge products. The Water Utilisation in Agriculture (WUA) section has, over the years, produced valuable knowledge to guide the harvesting and conservation of rainwater to improve agricultural productivity among smallholder crop farmers and household food producers. This knowledge is useful for especially the many women farmers around the country growing crops to feed their families, and whenever possible selling excess to generate some income. However, one of the problems experienced in the field is that this knowledge does not always reach the intended audience. This is the problem that the Amanzi [Water] for Food project was engaged with.
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- Date Issued: 2018
Exploring the potential of developmental work research and change laboratory to support sustainability transformations: a case study of organic agriculture in Zimbabwe
- Authors: Mukute, Mutizwa , Mudokwani, Kuda , McAllistair, Georgina , Nyikahadzoi, Kefasi
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392119 , vital:68723 , xlink:href="https://doi.org/10.1080/10749039.2018.1451542"
- Description: This paper explores the emergence of transgressive learning in CHAT-informed development work research in a networked organic agriculture case study in Zimbabwe, based on intervention research involving district organic associations tackling interconnected issues of climate change, water, food security and solidarity. The study established that We change laboratories can be used to support transgressive learning through: confronting unproductive local norms; collective reframing of problematic issues; stimulating expansive learning and sustainability transformations in minds, relationships and landscapes across time. The study also confirms the need for fourth generation CHAT to address the complex social-ecological problems of today.
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- Date Issued: 2018
Extending functionality and knowledge transfer of the Water Quality Systems Assessment Model
- Authors: Slaughter, Andrew , Gwapedza, David , Mantel, Sukhmani K , Hughes, Denis A , Griffin, Neil J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438115 , vital:73436 , ISBN 978-0-6392-0059-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2448_final.pdf
- Description: This report has been generated by the Water Research Commission (WRC) funded project Developing Climate Change Adaptation Measures and Decision-Support System for Selected South African Water Boards (Project No. K5/2018).
- Full Text:
- Date Issued: 2018
Extending the NFComms framework for bulk data transfers
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430152 , vital:72669 , https://doi.org/10.1145/3278681.3278686
- Description: In this paper we present the design and implementation of an indirect messaging extension for the existing NFComms framework that pro-vides communication between a network flow processor and host CPU. This extension addresses the bulk throughput limitations of the frame-work and is intended to work in conjunction with existing communication mediums. Testing of the framework extensions shows an increase in throughput performance of up to 300× that of the current direct mes-sage passing framework at the cost of increased single message laten-cy of up to 2×. This trade-off is considered acceptable as the proposed extensions are intended for bulk data transfer only while the existing message passing functionality of the framework is preserved and can be used in situations where low latency is required for small messages.
- Full Text:
- Date Issued: 2018
Family functioning and socioeconomic status in South African families: A test of the social causation hypothesis
- Authors: Botha, Ferdi , Booysen, Frikkie , Wouters, Edwin
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433176 , vital:72948 , xlink:href="https://doi.org/10.1007/s11205-017-1600-x"
- Description: Optimal family relationships are central to individual well-being. The focus of this paper is on family functioning and how socioeconomic status (SES) explains family functioning. Ecological theory states that a family’s socioeconomic context is determined by macro-systemic factors, thereby influencing individuals’ perceptions of family functioning. Within this context, the social causation hypothesis asserts that social conditions influence family functioning. This paper uses the Family Attachment and Changeability Index as measure of family functioning. SES is viewed as multidimensional and individual-, household-, and subjective SES indices are developed using multiple correspondence analysis. Multivariate regression models suggest that household- and subjective SES are associated with higher levels of perceived flexibility in the family. There is no association between SES and family members’ attachment to each other. In general, the findings support the social causation hypothesis.
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- Date Issued: 2018
From deviant choice to feminist issue: An historical analysis of scholarship on voluntary childlessness (1920–2013)
- Authors: Lynch, Ingrid , Morison, Tracy , Macleod, Catriona I , Mijas, Magdalena , du Toit, Ryan , Shivakumar, Seemanthini T
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434319 , vital:73048 , ISBN 978-1-78754-361-4 , https://www.emerald.com/insight/content/doi/10.1108/978-1-78754-361-420181002/full/html
- Description: Existing reviews of research on voluntary childlessness generally take the form of narrative summaries, focusing on main topics investigated over time. In this chapter, the authors extend previous literature reviews to conduct a systematic review and content analysis of socio-historical and geopolitical aspects of knowledge production about voluntary childlessness. The dataset comprised 195 peer-reviewed articles that were coded and analysed to explore, inter alia: the main topic under investigation; country location of authors; sample characteristics; theoretical framework and methodology. The findings are discussed in relation to the socio-historical contexts of knowledge production, drawing on theoretical insights concerned with the politics of location, representation and research practice. The shifts in the topics of research from the 1970s, when substantial research first emerged, uphold the view of voluntary childlessness as non-normative. With some regional variation, knowledge is dominated by quantitative, hard science methodologies and mostly generated about privileged, married women living in the global North. The implications of this for future research concerned with reproductive freedom are outlined.
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- Date Issued: 2018
Glycosylated zinc phthalocyanine-gold nanoparticle conjugates for photodynamic therapy
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
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- Date Issued: 2018
Green skills Transformative niches for greening work
- Authors: Ramsarup, Preesha , Rosenberg, Eureta , Lotz-Sisitka, Heila , Jenkin, Nicola
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436882 , vital:73313 , ISBN 978-981-15-6370-6 , https://doi.org/10.1007/978-981-15-6370-6_8
- Description: Supporting green skills development is integral in the transition to a green economy. Green skills can be difficult to define and measure at an aggregate level because they are a socially constructed concept, intangible and are often unobservable. Further, a demand-led approach to green skills has not worked because employers are unable to effectively articulate their needs to skills delivery bodies. This advances the need for a transformative methodology that is able to provide a more nu-anced view of skills planning to support green work. Drawing on transition theorists, this chapter demonstrates that greening work transitions occur in “niches” at local levels, where nexus concerns arise around the impetus to green work. Furthermore, it is from these transformative niches that wider social changes and regime shifts are driven or emerge. Using experiences from the chemicals sector in South Africa, the chapter illus-trates the need to develop non-reductionist conceptualisations that illustrate the “regime lock-ins” as well as green skills oppor-tunities at multiple levels.
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- Date Issued: 2018
HIV/AIDS and other household shocks as catalysts of local commercialization of non-timber forest products in Southern Africa
- Authors: Weyer, Dylan J , Shackleton, Charlie M , Adam, Y O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398223 , vital:69385 , xlink:href="https://doi.org/10.1111/dpr.12261"
- Description: Local trade in non-timber forest products (NTFPs) is increasing globally, yet the causes have been little studied. We examine household shock as a driver of NTFP trade in five southern African countries, with an emphasis on HIV/AIDS-related illness and death. Over the past two years, 95% of trader households experienced at least one shock, with family illness and death recorded for 68% and 42% of households, respectively. Almost 40% had entered the trade because of HIV/AIDS-related shocks. Additional shocks included natural disasters, crop pests or failure and livestock loss. The sale of NTFPs was the third most common coping strategy, after kinship and agricultural adjustments. Coping strategies differed between sites and type of shock.
- Full Text:
- Date Issued: 2018
Household food insecurity along an agro-ecological gradient influences children’s nutritional status in South Africa
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179836 , vital:43193 , xlink:href="https://doi.org/10.3389/fnut.2017.00072"
- Description: The burden of food insecurity and malnutrition is a severe problem experienced by many poor households and children under the age of five are at high risk. The objective of the study was to examine household food insecurity, dietary diversity, and child nutritional status in relation to local context which influences access to and ability to grow food in South Africa and explore the links and associations between these and household socio-economic status. Using a 48-h dietary recall method, we interviewed 554 women from randomly selected households along a rural–urban continuum in three towns situated along an agro-ecological gradient. The Household Dietary Diversity Scores (HDDS) and the Household Food Insecurity Access Scale (HFIAS) tools were used to measure household dietary diversity and food insecurity, respectively. Anthropometric measurements with 216 children (2–5 years) from the sampled households were conducted using height-for-age and mid-upper arm circumference (MUAC) as indicators of stunting and wasting, respectively. The key findings were that mean HDDS declined with decreasing agro-ecological potential from the wettest site (8.44 ± 1.72) to the other two drier sites (7.83 ± 1.59 and 7.76 ± 1.63). The mean HFIAS followed the opposite trend. Stunted growth was the dominant form of malnutrition detected in 35% of children and 18% of children were wasted. Child wasting was greatest at the site with lowest agro-ecological potential. Children from households with low HDDS had large MUAC which showed an inverse association among HDDS and obesity. Areas with agro-ecological potential had lower prevalence of food insecurity and wasting in children. Agro-ecological potential has significant influence on children’s nutritional status, which is also related to household food security and socio-economic status. Dependence on food purchasing and any limitations in households’ income, access to land and food, can result in different forms of malnutrition in children. Responses to address malnutrition in South Africa need to be prioritized and move beyond relying on food security and nutritional-specific interventions, but rather on nutrition-specific and sensitive programs and approaches; and building an enabling environment. Land availability, agriculture (including climate-smart agriculture especially in drier areas), and wild foods usage should be promoted.
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- Date Issued: 2018
How are learning and training environments transforming with ESD
- Authors: O’Donoghue, R , Taylor, Jim , Venter, V
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436718 , vital:73295 , ISBN 978-92-3-100244-1 , https://unesdoc.unesco.org/ark:/48223/pf0000261445
- Description: Action Area 2 of the Global Action Programme (GAP) on Edu-cation for Sustainable Development calls for the transformation of education and training environments1. This transformation can be interpreted in terms of changes in learning environ-ments brought about by the inclusion of ESD in education and training initiatives. This includes the integration of learning-led change found in whole-school approaches that emphasize in-clusive school governance, pedagogy and sustainable cam-pus management, as well as cooperation with partners and broader communities. These approaches are changing learn-ing environments in significant ways.
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- Date Issued: 2018
How important is green infrastructure in small and medium-sized towns? Lessons from South Africa
- Authors: Shackleton, Charlie M , Blair, Andrew , De Lacy, Peter , Kaoma, Humphrey , Mugwagwa, Noster , Dalu, Mwazvita , Walton, Wesley
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398321 , vital:69400 , xlink:href="https://doi.org/10.1016/j.landurbplan.2016.12.007"
- Description: The current nature and challenges of urbanisation in sub-Saharan Africa display several unique features only weakly evident on other continents. Key ones include the current high rates of population growth, inadequate planning and governance systems, concentration in small and medium-sized towns, and increasing urban poverty. These shape the extent, nature and use of ecosystem services provided by urban green infrastructure. This paper first examines the location of green infrastructure across nine towns, showing that it is unequal between suburbs and that the bulk is located under private tenure (74%) rather than in public spaces. We then consider the extent and patterns of use of selected provisioning and cultural ecosystem services from green infrastructure in different locations within towns, including private gardens, public parks and street trees. The results show significant use of green infrastructure for a range of provisioning and cultural services as well as its contribution to spiritual and mental wellbeing. Provisioning contributions are both in regular support of livelihood needs as well as increased use after a covariate shock (a flood), both of which help reduce household vulnerability. Lastly, our results show the expressed level of support and willingness-to-pay or work amongst urban residents for green infrastructure and the services it provides. Whilst the composite results indicate marked variation between and within towns, they show that there is widespread use of green infrastructure for both basic needs as well as for more aesthetic and psycho-spiritual appreciation and recreation, in small and medium-sized towns in a developing country such as South Africa.
- Full Text:
- Date Issued: 2018