Developing biological control agents for the management of the invasive tree Robinia pseudoacacia
- Authors: Wolmarans, Abigail
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435717 , vital:73181 , DOI 10.21504/10962/435717
- Description: Robinia pseudoacacia (Fabaceae) is a deciduous tree native to the Appalachian Mountains of North America but has become naturalised and invasive in other countries such as temperate North America, Europe, Australia, and Southern Africa. In South Africa the tree is classified as a category 1B invasive alien under the National Environmental Management Act (NEMBA), which stipulates the species requires some form of control as it has already caused extensive negative ecological and economic impacts. In the invaded range the tree creates monocultures that displace native species and spreads rapidly from suckering roots, making it a proficient invader. The South Africa plant prioritisation system suggests R. pseudoacacia is in the top three species which should be considered for classical weed biological control in South Africa. This thesis investigates which insects known to be associated with tree should be prioritised as candidate agents, as well as offering interesting insights into prioritising insects for weed biological control and using plant phylogenies and available literature to predict insect specificity. To ensure that no candidate biological control agents were already present in South Africa as well as to prioritise which guilds of the tree to prioritise for potential biological control, pre-release surveys were conducted across nine sites where the tree has invaded South Africa. It was found that no insects from the native range of R. pseudoacacia were present in South Africa. Seed surveys revealed that generalist insects attack a sizable proportion (68 %) of the seeds on the trees. In combination with a low seed soil bank (15.8 %) this suggests that seed- feeding agents may be helpful, however, candidate agents which damage leaves should be prioritised due to R. pseudoacacia relying heavily upon vegetative reproduction and much less on sexual reproduction. Leaves may therefor reduce the spread of these invasive trees. The insect assemblages in the native range of R. pseudoacacia are well understood. In addition, several associated insects have unintentionally followed the tree on its global spread, where they are often regarded as pests. The third chapter is therefore aimed at prioritising the known insects associated with the tree in both the native and invaded range. Literature surveys and Harris (1973) prioritisation systems were used to prioritise close to 64 candidate biological control agents down to three foliage- feeding agents, namely Odontota dorsalis (Coleoptera, Chrysomelidae), Macrosaccus robiniella (Lepidoptera, Gracillariidae) and Obolodiplosis robiniae (Diptera, Cecidomyiidae). To further prioritise the six selected agents in Chapter 4, species distribution were modelled with known climatic variables. This was done by using the species known occurrence localities, from both the native and where applicable invaded ranges, to identify which species that would best match with South Africa’s climate. The study showed that O. dorsalis is best suited to survive in South Africa, followed by O. robiniae and then M. robiniella. Collected data aided in the introduction of the prioritised O. robiniae into South African quarantine facilities. Unfortunately, despite several attempts, cultures could not be established, making conventional host specificity testing impossible. Thus, in Chapter 5 we aimed to determine the potential host range of the midge using information from experts in the field of galling insects, literature surveys, agricultural pest lists, and social science platforms coupled with native and invaded range surveys. The list of non-target species to consider as potential hosts was refined by developing phylogenetic trees of closely related Fabaceae that share the same distribution (native and invaded) as R. pseudoacacia. Through the available information gathered, and field surveys of these species, O. robiniae has not been shown to utilise any species, other than those from the Robinoid clade. In addition, the midge has also never been recorded on a number of closely related leguminous fodder and horticultural species growing in close proximity at high densities to R. pseudoacacia - suggesting negligible risk to South African growers of the same species. Host-specificity assessments through field surveys can be regarded as one of the best indicators of the ecological host range, however, this information is difficult to quantify and infrequently available, thus seldom used when determining the safety of a candidate biocontrol agent. In this unique study, using the extensive data collected we are able to show that O. robiniae would be potentially safe for release in South Africa. However, open field tests exposing closely related non-target plant species under natural and semi-natural conditions are planned in Switzerland over the next two years aiming to confirm these conclusions. By identifying and prioritizing potential biological control agents, this research contributes to the development of a targeted and sustainable solution for managing R. pseudoacacia in South Africa. The economic implications of successful biological control include reduced costs associated with invasive species management and ecosystem restoration. Additionally, by mitigating the negative ecological impacts, the agricultural systems in affected regions stand to benefit from enhanced resilience and productivity. Furthermore, the study's approach of using plant phylogenies and available literature to predict insect specificity offers a valuable methodological contribution to the broader field of weed biological control. This methodology can be adapted and applied to other invasive species, providing a framework for efficient and informed decision-making in weed management strategies. In essence, this research not only addresses the specific challenges posed by R. pseudoacacia in South Africa but also provides a template for tackling similar issues in different geographical contexts, thereby contributing to global efforts in sustainable agriculture and environmental conservation. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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- Date Issued: 2024-04-05
The regulation of privacy on cloud computing services in terms of the Protection of Personal Information Act 4 of 2013
- Authors: Malahleka, Mthuthukisi
- Date: 2022-04-06
- Subjects: South Africa. Protection of Personal Information Act, 2013 , Cloud computing Law and legislation South Africa , Data protection Law and legislation South Africa , Personal information management South Africa , Data privacy South Africa , Computer security Law and legislation South Africa , General Data Protection Regulation (GDPR)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290731 , vital:56779
- Description: There is a relatively new development in Information Technology (IT) space known as cloud computing, software and service delivered remotely through the Internet without installing software on a computer. Cloud computing has quickly gathered steam as one of the most prominent topics in IT, and indeed within the business sector as a whole. Cloud computing is one such development associated with opportunities and benefits, especially in the commercial sector. Due to the development of IT and many businesses adopting e-commerce business-related strategies, cloud computing has revolutionised how personal information is processed. The advent of cloud computing as a mechanism to process personal information has brought many legal challenges for protecting the right to privacy enshrined under section 14 of the South African Constitution, which is a vulnerable part of one’s personality right. The right to privacy has long been protected even before adopting the Constitution under the common law of delict (actio iniuriarumn). As the adoption rate of cloud computing services by businesses continues to increase, the legal considerations and risks become more prevalent. The lawmakers struggle to keep pace with the rapidly changing technological advancements, at least for now. Both the common law and the Constitution could not address all the legal aspects of data protection and the adoption of cloud computing services hence the promulgation of the Protection of Personal Information Act 4 of 2013 (POPI Act). The POPI Act’s main objective is to protect the personal information of both natural and juristic persons. Personal information about an individual forms part of privacy. Unlawful processing of such personal information is a violation of the right to privacy of an individual. It is now widely recognised that the unregulated processing of personal information significantly impacts fundamental human rights like privacy, personality, and autonomy. A close analysis of cloud computing regulation is necessary, as legal protection mechanisms must safeguard the processing of personal information and establish extraterritorial jurisdiction to regulate the use of cloud computing within national legislation as cloud computing provides a transnational characteristic on the cross-border flow of personal information. In this thesis, a question is asked on whether the current data protection laws in South Africa on protecting the right to privacy in the cloud computing services context are adequate. The analysis will determine whether the overlaps between these pieces of data protection laws are competent to deal with the ever-increasing threats on the right to privacy and if they meet the international data protection standards set by the European Union’s General Data Protection Regulation (GDPR). The research seeks to analyse and reveal the shortcomings under the Constitution and the common law that led to adopting the POPI Act by studying the regulation of cloud computing services. This analysis will determine the shortcomings of the POPI Act as well in the context of cloud computing. The research will then follow a comparative analysis of the POPI Act and the GDPR to determine the application of the GDPR on international data breaches and compare its provisions with the POPI Act in the context of cloud computing. Finally, the research will address the question as to whether a multi-faceted approach, which includes a Model Law on cloud computing, would be an appropriate starting point setting out requirements for the use of this technology can be sufficient in protecting data subjects. And as cloud computing risks are not only a national but also a global problem, South Africa needs to look at the option of entering into mutual agreements with other countries and organisations to regulate cloud computing at an international level. , Thesis (LLM) -- Faculty of Law, Law, 2022
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- Date Issued: 2022-04-06