Extract from The 1957 Conference Report of “Park Administration", in which the then Director of the National Botanical Gardens of South Africa, Professor H B Rycroft, appeals to the inclusion of South African indigenous plants in public parks and gardens.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The burgeoning problem of alien plant invasions in South Africa necessitates effective decision-making based on an understanding of the complex processes that govern these invasions. Due to the spatial nature of the problem, this study explored the use of Geographic Information Systems and spatial models for predicting the spread of alien vegetation and assessing the effectiveness of clearing strategies. The Spatially Explicit Individual Based Simulation (SEIBS) model was identified as a potentially useful tool for alien plant management. This thesis documents the further investigation and development that was necessary before recommendations could be made regarding the future use of the model. The landscape version of the SEIBS model was adapted to allow for the convenient input and output of spatial data, making it possible to simulate invasions in different areas. An ArcView extension was developed in order to facilitate the pre- and post-processing of the spatial data required and created by the model. Changes were also made to the fire routine of the model. The new version of the model was called Clear. A series of model tests for Pinus pinaster were conducted to assess the sensitivity of the Clear model to spatial resolution, initial spatial fragmentation and heterogeneity. These tests revealed that the model was sensitive to changes in resolution and needed to be reparameterised when using different resolutions. The initial level of fragmentation was shown to have a major influence on the invasion rate. Although greater levels of spatial heterogeneity with respect to vegetation age did not significantly affect the spread rate, it did increase the effectiveness of clearing strategies based on clearing juvenile or sparse vegetation. Based on these tests, it is concluded that the model can be readily applied to different areas, provided the influence of spatial characteristics is understood and accommodated. The Clear model was shown to be a useful tool for evaluating clearing strategies and for investigating invasion rates. It is recommended that the model be introduced to a wider audience, in order to obtain user feedback and further improve the accessibility of the model. / AFRIKAANSE OPSOMMING: Die toenemende probleem van uitheemse indringerplante in Suid Afrika, noodsaak effektiewe besluitneming wat gebaseer is op 'n begrip van die ingewikkelde prosesse wat indringing beheer. As gevolg van die ruimtelike geaardheid van die probleem, is die gebruik van Geografiese Inligtingstelsels en ruimtelike modelle vir die voorspelling van die verspreiding van indringerplante en die evaluasie van die effektiwiteit van opruimingstrategieë in hierdie studie ondersoek. Die Spatially Explicit Individual Based Simulation (SEIBS) model is as 'n moontlike geskikte hulpmiddel vir die bestuur van uitheemse indringerplante geïdentifiseer, alhoewel verdere ondersoeke en ontwikkeling nodig was voordat aanbevelings vir die gebruik van die model gemaak kon word. Vir hierdie studie is die landskapweergawe van die SEIBS model aangepas om die maklike toevoer en afvoer van ruimtelike data te fasiliteer. 'n ArcView uitbreiding is ontwikkel om met die voor- en naprosessering van ruimtelike data, wat deur die model gebruik en geskep is, te fasiliteer. Veranderinge is ook aan die vuur sub-roetine van die module gemaak. Die nuwe weergawe van die model word Clear genoem. 'n Reeks toetse is vir Pinus pinaster gedoen om die sensitiwiteit van die Clear model te toets teenoor ruimtelike resolusie, aanvanklike vlak van versnippering en vlak van heterogeniteit. Vanuit die toetse het dit geblyk dat die model sensitief was ten opsigte van verandering in resolusie en dat die model se parameters verstel moes word wanneer verskillende resolusies gebruik word. Daar is ook gewys dat die die vlak van aanvanklike versnippering 'n groot impak op die verspreidingstempo het. Alhoewel hoër vlakke van ruimtelike heterogeniteit teenoor plantegroei nie 'n merkbare impak op die verspreidingstempo gehad het nie, het dit wel die effektiwiteit van opruiming-strategieë, gebaseer op die opruiming van jong of yl verspreide plante, verbeter. Die gevolgtrekking wat uit die toetse gemaak kan word is dat die model geredelik op verskillende areas toegepas kan word, op die voorwaarde dat die invloed van ruimtelike eienskappe in ag geneem word en in berekening gebring word. Dit word aanbeveel dat die model wyer bekendgestel word om sodoende gebruikersterugvoer te bekom.

Ph.D. (Chemistry) / The Forensic Chemistry Laboratory of Johannesburg (FCL JHB) is tasked with the chemical analysis of a variety of samples to assist in determining the cause of death where unnatural cause is suspected. Some of the samples submitted to the laboratory have a herbal or muti connotation, but a large portion of these cases turn out to have no herbal components present as only pharmaceutical or agricultural products are detected in these samples. This study combined, for the first time, forensic investigation, chemistry and botany to create a unique platform needed for the identification of poisonous plants and their components in forensic exhibits and viscera. The research was focussed on the poisonous plants previously detected at the laboratory, as well as the requests received for the analysis of muti/toxic plant components. The selection of plants included Nicotiana glauca, Datura stramonium / Datura ferox, Callilepis laureola, Boophone disticha / Ammocharis coranica, Abrus precatorius, Ricinus communis, Nerium oleander / Thevetia peruviana and Bowiea volubilis. All these species are known to have caused fatalities, hence their choice. Nicotiana glauca has been implicated in the deaths of at least 15 people since 2001. It was previously detected by GC-MS (EI) in plant exhibits, but could not be detected in a viscera matrix. A selective extraction method for alkaloids was used to extract botanical and viscera samples. Anabasine was successfully detected on the HPLC-MS (EI) system but this detection technique was not considered sensitive enough. A very sensitive HPLC-MS method was developed on the ZMD detector by using electrospray technology. This method outperformed both electron impact detectors (GC and HPLC) and could detect 1ng/ml anabasine with relative ease in full scan mode. Datura stramonium and D. ferox have not been previously positively linked to any human poisoning or death due to exposure to botanically derived products at the FCL JHB. Atropine and scopolamine were successfully ionised in ESI positive mode and could be detected at 10 pg/ml and 100 pg/ml level respectively. The identities of the compounds were confirmed by characteristic ISCID fragmentation patterns. The developed method was successfully applied to a suspected heart attack case. The results proved conclusively that the deceased was given D. ferox seeds as part of his meal and an overdose of atropine and scopolamine contributed to his death...

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. 25 October 2016 in Johannesburg, South Africa. / Ecosystem services, nature’s benefit to people, contribute to human well-being. Extensive reliance on, and unsustainable use of, natural resources is typical of the rural poor in developing countries and can lead to ecosystem degradation, decreased ecosystem service provision, and increased vulnerabilities of rural populations. Most ecosystem services are intangible or difficult to quantify, but fuelwood provisioning can be measured directly and can serve as a proxy for the status of other ecosystem services (e.g. aesthetic and spiritual services, nutrient cycling, carbon sequestration). South African rural communities have a high reliance on fuelwood despite extensive access to electricity. Within this context, live wood harvesting occurring around rural settlements in increasing amounts has been deemed unsustainable. However, the ‘fuelwood crisis’ of the 1970s, and subsequent predictions of woodland collapse through fuelwood supply-demand models, has still not occurred despite substantial population growth in developing countries. Hypothesised reasons for modelled supply-demand mismatches are based on underestimation of fuelwood supply and woodland regeneration, as well as overestimation of fuelwood demand by discounting behavioural adaptability of users. It is likely that the spatial configuration of fuelwood use allows for the co-adaptability of both humans and ecosystems. A lack of understanding of the spatial configuration of these social-ecological dynamics limits our insights into current and future adaptive responses and thus, the degree of sustainability. This thesis aimed to assess woody biomass stocks and vertical structure changes, as a proxy for provisioning ecosystem services, in a spatially and temporally explicit manner, to describe the status and impact of wood extraction in semi-arid, savanna communal lands. Using repeat, airborne light detection and ranging (LiDAR) data from 2008 and 2012, we surveyed three-dimensional woodland structure in Bushbuckridge Municipality communal lands – the grazing and harvesting areas for densely populated rural settlements in former Apartheid ‘homelands’ in South Africa. Woody biomass in 2008 ranged from 9 Mg ha-1 on gabbro geology to 27 Mg ha-1 on granitic geology. Land-use pressure was associated with compensatory regrowth of savanna tree species through post-harvest coppice in the 1-3m height class. Woody biomass increased at all sites, contrary to previous fuelwood models of the area. Change detection in the vertical canopy structure revealed that biomass increases were almost solely attributable to the 1-3m and 3-5m height classes. These changes were exacerbated by wood extraction intensity in the communal lands – the communal land with the highest wood extraction pressure experienced the greatest biomass increases, likely a strong regrowth response to high harvesting levels. Within communal lands, areas closest to roads and settlements experienced substantial biomass increases as a result of shrub level gains. This relationship was mediated by the usage gradient – the greater the wood extraction pressure on the communal land, the larger and more spatially coalesced the ‘hotspots’ of shrub-level increases were in relation to ease of access to the communal land. However, biomass increases are not necessarily indicative of woodland recovery, as shrub-level increases were coupled with losses of trees >3m in height. To explore these tall tree dynamics further, we tracked >450 000 individual tree canopies over two years over contrasting landscapes – a private reserve containing elephants, two communal lands under different wood extraction pressures, and a nature reserve fenced off from both elephants and humans. Humans are considerable drivers of treefall (defined here as a ≥75% reduction in the maximum height of each tree canopy) in communal lands. Humanmediated biennial treefall rates were 2-3.5 fold higher than the background treefall rate of 1.5% treefall ha-1 (in the control site – the reserve containing neither elephants nor humans). Elephant-mediated treefall was five fold higher than the background rate. Rate and spatial patterns of treefall were mediated by geology and surface water provision in the elephantutilised site where relative treefall was higher on nutrient-rich geology, and intense treefall hotspots occurred around permanent water points. Human-mediated rates and spatial patterns of treefall were influenced by settlement and crop-land expansion, as well as ease of access to communal lands. Frequent fires facilitated the persistence of trees >3m in height, but was associated with height loss in trees <3m. The combined loss of large trees and gain in shrubs could result in a structurally simple landscape with reduced functional capacity. Shrub-level increases in the communal lands are likely an interactive combination of newly established woody encroachers and strong coppice regrowth in harvested species. The more intensely used the communal land, the greater the bush thickening and the stronger the relationship between biomass gains and structural changes in the lowest height classes. The exacerbation of bush thickening in natural resource-dependent communities has critical implications for ecosystem service provision. There is potential for coppice regrowth to provide fuelwood to communities using ‘tree thinning’ programmes, but there is a lack of data on the quantity and quality of the regrowth, as well as the sustainability of coppice, the impacts of different harvesting methods, and the potential feedbacks with changing climate and CO2 fertilisation. Woody resource spatial distribution in communal lands is centred around settlement-level wood extraction pressure, as well as natural resource accessibility in the woodlands. In highly utilised areas, woodland regenerative capacity has been underestimated. Additionally, natural resource extraction is still highly localised, even at the communal land scale, with major structural changes occurring around the periphery or close to existing infrastructure. However, it is these underrated coupled adaptive responses in social-ecological systems that explain the failure of fuelwood supply-demand models’ predictive abilities. Nevertheless, loss of large trees in the landscape and the persistence of ‘functionally juvenile’ coppice stands will have implications for seedling production and establishment in the landscape with repercussions for the future population structure and ecosystem service provision. I discuss the implications of increased natural resource reliance in an African development context and the positive feedback between rural poverty and environmental impoverishment. Potential constraints to the data are unpacked, together with opportunities for further research in this area. / LG2017

The thesis presents a thorough, in-depth study that fills some of the gaps in the knowledge of the impacts of woodland utilisation in communal areas. The chosen case study villages are in Bushbuckridge, a government gazetted Integrated Sustainable Rural Development programme node, making the results pertinent to sustainable energy policy reform in South Africa. A case-study of two villages was used to investigate the spatial and structural changes in fuelwood supply in response to fuelwood extraction as well as the changes in use-patterns over time. A survey of the structure and composition of the woody vegetation and wood harvesting patterns around the villages was conducted and compared against historical data, spanning 17 years. Total wood stock in the communal woodlands of both villages declined over the study period; the loss being greater in Welverdiend. Significant, negative change in the structure and species composition, particularly of species that are commonly harvested for fuelwood has occurred in Welverdiend but not in Athol. The absence of negative impacts in Athol implies that harvesting regimes here are more sustainable but it is more likely that this is due to the lower human population and lower fuelwood extraction pressure. The changes in woodland structure were linked to landcover change patterns that occurred in the villages over the last 44 years, from their creation through forced resettlements on old farms in the area. Landcover change patterns were similar in both villages since 1965 but there was significantly greater woodland loss in Welverdiend (48% woodland loss) in comparison to Athol (25% woodland loss). The systematic loss of woodland areas to agricultural fields was linked to expanding residential areas due to human population growth. Deforestation occurred where woodlands were already impacted through selective harvesting. The physical changes in woodland structure and landcover were linked to a detailed socio-economic analysis of the two villages, providing critically important data for the sustainable management of woodlands in South Africa. The impact of access to electricity on fuelwood consumption rates was carried out through analysis of the economic, time and opportunity costs of fuelwood collection, compared against the different fuelwood availability in each village. In Welverdiend demand for fuelwood has so far proved inelastic; households have adjusted their fuelwood collection regimes, going on fewer collection trips but spending longer times for each trip but ultimately household investment is similar to that in Athol. Fuelwood demand is maintained in Welverdiend by the availability of purchased fuelwood and harvesting in new sites. A model to predict the socio-economic factors at the household and per capita level which affect fuelwood consumption was developed. Revealing in the process that households with access to electricity used less fuelwood annually and the amounts of fuelwood used were influenced by the household perceptions of fuelwood scarcity in the village, Household population size had a direct bearing on the likelihood of households switching to electricity with every addition to the household size decreasing the likelihood of switching by 48%. This study has major implications for the government’s on-going rural electrification programme. Interventions are required that raise awareness about fuelwood availability trends, based on landscape developments and targeting women as the main users of fuelwood.

A thesis submitted to the Faculty of Science, University of the Witwatersrand in fulfilment of the requirements for the degree of Doctor of Philosophy. November 2016. / This research was directed towards the environmental monitoring and assessment of the most used non-steroidal anti-inflammatory drugs (NSAIDs) which are naproxen, ibuprofen and diclofenac. The work involved the development and application of sensitive techniques for the quantification of naproxen, ibuprofen and diclofenac in the South African aquatic environment. Based on this information, a multi-templates molecularly imprinted polymer (MIP) was synthesized and applied alongside the commercial available sorbent (Oasis MAX) in the solid-phase extraction (SPE) of target compounds from water samples. The extracted compounds were then quantified using high performance liquid chromatography (HPLC). MIP was synthesized by applying a bulk polymerization approach at 70 ͦ C where all target compounds were used as multi-templates. Other reagents used in synthesis were 2-vinyl pyridine, 1,1’-azobis-(cyclohexanecarbonitrile), ethylene glycol dimethacrylate and toluene as functional monomer, initiator, cross-linker and porogenic solvent, respectively. Synthesis of a non-imprinted polymer (NIP) under similar reaction conditions as MIP was carried out with the omission of templates. Techniques employed in characterization of MIP and NIP were Fourier transform infrared spectroscopy (FTIR), Brunauer, Emmett and Teller (BET) method, CHNS analyzer, zeta potential, cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and x-ray diffraction. Monomer-template interactions were investigated using molecular dynamics. The performance of the MIP was evaluated based on its ability to selectively extract target compounds in organic (acetonitrile, acetone, chloroform and toluene) and aqueous media. The extraction capacity of the MIP in organic solvents for naproxen, ibuprofen and diclofenac increased from high polarity to low polarity solvents. In a low polarity solvent (toluene), the extraction capacity achieved for naproxen, ibuprofen and diclofenac were 14.4, 11.0 and 14.0 mg/g, respectively. In this case, the selectivity of the MIP where gemfibrozil was employed as the competing species was evident. Selectivity of the MIP collapsed during the adsorption of naproxen, ibuprofen and diclofenac from water using gemfibrozil and fenoprofen as competitors. This resulted in high extraction efficiencies for target compounds and competitors, however, both gemfibrozil and fenoprofen were easily desorbed from the MIP using weak organic solvent due to lack of molecular recognition. During the binding sites characterization, the best fit of pseudo-second-order implied a chemisorption of all target compounds onto MIP sorbent. The data also fitted well in Langmuir isotherm which meant that the adsorption of target pharmaceuticals occurred on the homogeneous binding sites of the MIP. Optimized adsorption conditions in water such as MIP amount of 50 mg, extraction time of 10 min, sample pH of 2.5 and sample volume of 10 mL were applied for the selective adsorption of naproxen, ibuprofen and diclofenac in contaminated wastewater and river water. In WWTP influent, naproxen recovery was 38%, whereas ibuprofen and diclofenac were 69% and 87%, respectively. MIP was further used as a selective adsorbent in solid-phase extraction (SPE) of three drugs from environmental samples. The selectivity of the MIP in environmental samples was compared to that of the commercially available Oasis MAX sorbent. The application of molecularly imprinted solid-phase extraction (MISPE) reduced matrix effects and improved the sensitivity of the analytical method. In this case, the detection limits for naproxen, ibuprofen and diclofenac were 0.2, 1 and 0.6 μg/L, respectively. When deionized water was spiked with 5 and 50 μg/L of target compounds, recoveries greater than 80% were obtained. Thereafter, the developed MISPE was applied for selected acidic drugs from environmental samples. Environmental samples were collected from urban (Durban) and semi-urban/rural areas (Ladysmith) of KwaZulu-Natal Province in South Africa. The most abundant compound in the environment was ibuprofen. In river water samples from Durban, the maximum concentrations found for naproxen, ibuprofen and diclofenac were 6.8, 19 and 9.7 μg/L, respectively. The maximum amounts found for the same drugs in Ladysmith river samples were generally lower with naproxen, ibuprofen and diclofenac detected at 2.8, 6.7 and 2.6 μg/L, respectively. The same trend was observed in wastewater. Further work on the monitoring of acidic compounds in wastewater was conducted using Oasis MAX as the SPE sorbent prior to HPLC analysis. All target compounds were detected in Kingsburg and Umbilo WWTPs located in Durban surroundings. The influent and effluent concentrations detected were in the ranges of 6.4 to 69 μg/L and 0.6 to 4.2 μg/L, respectively. Further to this, the removal efficiency of the target compounds during the WWTP process in Kingsburg and Umbilo was in the range of 69 to 97%. The extent of pollution in the environment was further assessed by the monitoring of ketoprofen and triclosan in wastewater and river water using SPE with Oasis HLB sorbent and HPLC. Traces of both compounds ranging from 1.2 to 9.0 μg/L were detected in wastewater. The maximum concentrations found in river water were 2.0 and 0.9 μg/L for ketprofen and triclosan, respectively. Overall, the analytical methods implemented in this work were highly accurate, precise and sensitive. The synthesized MIP was highly selective and its application in environmental studies led to the development of a less expensive analytical method. This work also gives the overview of the extent of water pollution caused by acidic pharmaceuticals in various water matrices. / MT2017

Lung infections in cystic fibrosis (CF) patients are very serious and are usually fatal. Prolonged antibiotic treatment can result in the development of antibiotic resistance. Thus, studies are required to determine if traditional medicinal plants have any significant effects (i.e. antibacterial effects in this case) on certain bacteria causing lung infections in CF patients, providing possible alternative treatment. The aim of this study was to test the effects of several Eastern Cape medicinal plants on specific bacteria causing lung infections in CF patients, for possible antibacterial activities. Four plants traditionally used to treat lung infections (Artemisia afra, Dodonaea angustifolia, Leonotis leonurus & Tulbaghia violacea), and different strains of four bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas species & Klebsiella pneumoniae), usually causing lung infections were investigated. Methanol, aqueous and acetone extraction methods were used to make extracts of the various plants chosen. A decoction of each plant was also investigated. An adapted microtitre plate method for testing the antibacterial activity of the plant extracts against the chosen bacteria was used. The minimum inhibitory concentration (MIC) of each plant extract was determined by means of this method.

M.Sc. (Geography) / Please refer to full text to view abstract

Artemisia afra is one of the oldest, most well known and widely used traditional medicinal plants in South Africa. It is used to treat many different medical conditions, particularly respiratory and inflammatory ailments. There is no reported evidence of its use for the treatment of cancer but due to its reported cytotoxicity, an investigation of the mode of cell death induced by an ethanol A. afra extract using two cancer cell lines was done. IC50 values of 18.21 and 31.88 μg/mL of ethanol extracts were determined against U937 and HeLa cancer cells, respectively. An IC50 value of the aqueous extract was greater than 250 μg/mL. The ethanol extract was not cytotoxic against confluent control cell lines, Chang Liver and Vero cells. The effect of the cytotoxic ethanol A. afra extract on U937 and HeLa cells and their progression through the cell cycle, apoptosis and mitochondrial membrane potential was investigated. After 12 hours of treatment with A. afra a delay in G2/M phase of the cell cycle was evident. Apoptosis was confirmed using the TUNEL assay for DNA fragmentation, as well as fluorescent staining with annexin V-FITC. Apoptosis was evident with the positive control and A. afra treatment at 24 and 48 hours. JC-1 staining showed a decrease in mitochondrial membrane potential at 24 hours. It was deduced that A. afra ethanol extract induces caspase-dependent apoptosis in a mitochondrial dependent manner. Plants harbour many compounds that are not only useful to the plants but also to mankind. Many metabolites have been isolated from A. afra and their biological activity characterised. Due to observed apoptosis induction, isolation of cytotoxic compounds was done and a new sesquiterpene lactone from A. afra was isolated. Structural elucidation of the compound was done by IR, 1D and 2D NMR, CD and mass spectrometry and it was identified as isoalantolactone. HeLa cancer cells were treated with isoalantolactone and cytotoxicity was exhibited in a dose-dependent manner. A low IC50 value of 8.15 ± 1.16 μM was achieved. This study showed that isoalantolactone is partly responsible for the observed A. afra cytotoxicity. Due to the evidence of G2/M arrest, the anti-mitotic potential and the possible onset of mitotic catastrophe by A. afra and isoalantolactone was investigated. It was evident from various flow cytometric analysis of cyclin B1 and phospho-H3 and confocal microscopy that A. afra does possess anti-mitotic activity by causing hyperpolymerisation of tubulin and cells progress into the mitotic phase where M arrest is experienced. The anti-inflammatory activity of sesquiterpene lactones is well documented; however, the anti-inflammatory activity of A. afra is not. Here, it is reported that the production of NO and COX-2 protein levels in RAW 264.7 cells decrease in the presence of A. afra and isoalantolactone after stimulation with LPS. The activated NF-κB subunit, p65 was also investigated. The results suggest that A. afra and isoalantolactone inhibit p65 activation as a decrease in the activated subunit was evident. Thus, the results indicate that exposure to A. afra and isoalantolactone induces an anti-inflammatory response. In conclusion, this study shows, for the first time, the mechanism of induced apoptosis, the anti-mitotic and anti-inflammatory activity of A. afra and its isolated compound, isoalantolactone. It also proves that although extensive research may have been done on a particular plant, as with A. afra, more can be discovered leading to the identification of new compounds and integration of signalling pathways that can be exploited for the treatment of various diseases and ailments.

No description available.