Dissertations / Theses on the topic 'Karoo'

Bibliography: leaves 56-65.
The following study was undertaken as part of the Karoo Biome Project (KBP) and sets out to investigate an aspect of karoo ecology that will contribute to a predictive understanding of both biotic and abiotic processes in the region for the development of meaningful management guidelines (Cowling, 1986).

Thesis (MSc)--University of Stellenbosch, 2000.
ENGLISH ABSTRACT: The composition and state of soil-stored seed banks on- and off the mesa Tafelberg, in the Nama Karoo rangelands of the Eastem Cape, South Africa, were investigated within the context of a broader restoration ecology project "Restoration of degraded Nama Karoo rangelands: the role of conservation islands'". The premise for this seed bank study was that restoration of degraded semi-arid rangelands is possible through applied management programs based on the methodology and practice of ecological restoration. Broadly acknowledged properties of non-equilibrium environments (e.g. unpredictable climates and varying degrees of disturbance) and soilstored seed banks (e.g. spatial and temporal distributions) formed the basis for investigating. the general environment and the properties.. of existing seed, banks, in the Tafelberg locality. The potential role of hills as refugia for palatable plant species was an under-lying element of the investigation. Following a brief investigation, of historical and contemporary research and policy on rangeland degradation in semi-arid regions of the world, the fundamental need for comprehensive and applied seed bank research in the Nama Karoo is emphasised. Within the framework of the umbrella project, the seed bank study examined local environmental criteria commencing with an investigation into seed bank- and vegetation habitats. Chemical and physical properties of soils from twenty two sites on- and off Tafelberg were described. Substantial soil habitat variation, between the top, the north west slopes and plains and the south east slopes and plains of Tafelberg, was identified. Micro-site variation between open-canopy (interplant spaces) and closed-canopy (under plant cover) microhabitats was found to be significant Primary soil habitat differences were linked to soil organic matter content which was found to be low on the plains relative to the top and slopes; and, low in open-canopy micro-sites relative to closed-canopy sites. Soil texture and nutrient composition on- and off Tafelberg was found to be highly variable with significant differences between the top and the plains as well as between the north west and south east plains. The slopes were found to be intermediate (showing some level of gradient) between the top and the plains. Soil nutrient variation was interpreted as a function of textural and parent-material properties of soils. Anthropogenic factors for accelerated erosion, deposition, leaching and salt-crust formation were also considered. It was concluded that while properties of soils on- and off Tafelberg are inherently related to parent soils, changes to textural and nutrient properties may be occurring and these changes may have been exacerbated by high levels of grazing. An investigation (focusing on small shrubs) of plant phenological response, in relation to rainfall and grazing gradients, identified trends of peak budding- and flowering seasons following rainfall during summer and autumn respectively. A continuum of seeding activity, with peaks in late autumn and early winter, was construed from quarterly data. Flush vegetative growth was noted for most small shrubs during spring, autumn and summer surveys. Since some form of activity related to reproductive output (flush growth, budding, flowering or seeding) was apparent at almost all times of the year, it is argued that high intensity disturbance (including grazing) might impact negatively on plant survival, leading to reduced reproductive input (i.e. seeds) into future generations. Plant communities on the top and plains are described noting significant differences between vegetation on top of Tafelberg (comprising primarily high production, palatable grass and shrub species) and that on the plains (comprising mainly spinescent, ephemeral, toxic and low production species). Given the high grazing pressure on the plains (relative to the less utilised slopes and top of Tafelberg), differences in vegetation composition are discussed in relation to studies elsewhere that describe degraded rangelands. It is concluded firstly that the plains surrounding Tafelberg are degraded, secondty that long term over-utilisation has altered vegetation composition and finally that inter-grazing rest periods of three- or six months alone may not restore vegetation diversity nor desirable plant species to the plains. Results of germination trials (investigating soil-stored seed banks) from two sampling episodes (spring and autumn 1998) revealed that seed banks in soils removed from the plains, slopes and top of Tafelberg followed distribution patterns observed in above-ground vegetation. Species-specific data was not finalised for this thesis since not all seedlings matured and flowered within given time constraints. In order to compare seedling emergence data, plant categories were developed that distinguished ephemerals versus persistent (perennial) species and dicotyledonous species versus grasses and other monocotyledonous plants. Samples from the top and the middle to upper slopes showed a high percentage of palatable and persistent grass and shrub species present in soil-stored seed banks while over twothirds of plants germinating from plains' soil samples were ephemeral species and most of these were both tiny «Scm) and short-lived «3 months). Most of the perennial species germinating from plains' samples were seedlings of Pentzia incana, Chrysocoma ciliata and succulents (mostly Mesembryanthemaceae) but few perennial grasses were present. On the other hand, roughly 94% of seedlings germinating from samples from the top and 63% of seedlings germinating from two slopes of Tafelberg respectively were persistent- grass or shrubby species. Roughly 89% of ephemeral species recorded from slopes' samples germinated from the lowest footslope sites. Seed densities were closely linked to micro-habitats with roughly three-fold differences between open- (lower seed density) and closed-canopy (higher seed density) micro-sites. Multivariate analysis of variance (MANOVA) indicated that most of the variation in seed density data was explained at the micro-habitat level. Seasonality played a secondary role with significant twoway interaction between the two effects. It is concluded that both factors must be considered when developing restoration programmes that aim to improve both overall plant cover and improved plant species diversity. While the original or "pristine" state of vegetation composition and seed banks on the plains is unknown, concems were raised regarding the apparently degraded state of total above- and below-ground plant diversity on these plains. A likely consequence of habitat degradation is that species with specific soil-, nutrient ratio-, aspect- and altitudinal requirements from the top and slopes of Tafelberg (as well as from nearby plains' refugia) may not be able to establish in degraded habitats on the plains. The identification of pioneer plant species (tolerant of habitat degradation) that allow increased vegetation cover and safe-sites for seedling germination of desirable plant species is recommended. Restoration programmes will need to be coupled with strict grazing management principles that allow seedling germination. establishment and successful reproductive output of desirable plants for future rangeland regeneration. Common and salient features of the soil habitat, plant pbenological response and germination trial studies are brought together in an examination of habitats and related seed bank diversity on- and off Tafelberg. Acknowledging the brevity of this research study, but utilising case studies from elsewhere and integrating both lines of questioning, the conclusion is again reached that the plains surrounding Tafelberg are degraded through decades and probably centuries of grazing by domestic livestock. It is considered crucial that restoration through improvement (or rehabilitation) of habitats and increased seedling safe-sites be considered. Both climate and grazing management appear to play an irrevocably linked role in shaping vegetation composition in rangelands. While rangelands are intrinsiCalfy adapted to surviving extremes of climatic variability found in non-equilibrium regions it is argued that the impacts of grazing, particularly during times of drought and climate change, are slowly reducing the intrinsic "buffer-capacity" of rangelands to withstand these changes and extremes. It seems apparent from research elsewhere that restoration through passive management is slow and probably not economically achievable within a viable time frame. The instifution and promotion of integrated and strategic programmes that identify and address issues of land degradation and land use change in semi-arid rangelands is recommended. The input and endeavours of different authorities, ministries and a broad public participation incentive are encouraged in these proposed programmes in order to ensure broadly-based input into long term sustainability and conservation of the considerable biological diversity of these regions. Seed bank assessment is considered to be a valuable means of indicating restoration potential and ranqeland condition with potential for the identification of both degraded and conservationworthy areas. Finally, some limitations and challenges of this study are examined through a process of firstly identifying alternative approaches to research methodologies and secondly through proposing recommendations for future research projects. While alternative methods could have been applied for the purposes of accomplishing this study it is concluded that, within the given time- and other constraints, the appropriate methods were applied.
AFRIKAANSE OPSOMMING: Die samestelling entoestand van groncbbewaarde saadbanke.op en van die mesa Tafelberg af, in die Nama Karoo weiveld van die Oos-Kaap, Suid-Afrika, is ondersoek binne die konteks van 'n wyer herstelekologieprojek: "Restourasie van oorbeweide Nama Karoo weiveld: die rol van bewannqseilande'". Die uitqanqspunt van hierdie saadbankondersoek was dat dit moontlik is om beskadigde semidroë weiveld te herstel deur middel van toegepaste bestuursprogramme wat gebaseer is op die metodologie en praktyk van ekologiese herstel. Algemeen erkende eienskappe van nieekwilibrium- omgewings (byvoorbeeld onvoorspelbare klimate en wisselende mates van versteuring) en grond-bewaarde saadbanke (byvoorbeeld ruimtelike en temporale verspreidings), het die basis gevorm vir die ondersoek van die algemene omgewing en die eienskappe van bestaande saadbanke in die Tafelberg omgewing. Die potensiële rol van heuwels as skuilplek vir aanvaarbare plantspesies was 'n onder1iggende element van die ondersoek. Na 'n kort ondersoek van historiese ~n kontemporêre navorsing en beleid oor weiveldbeskadiging in semi-droë streke van die wêreld, is die fundamentele behoefte aan omvattende en toegepaste saadbanknavorsing in die Nama Karoo beklemtoon. Binne die raamwerk van die oorkoepelende projek het die saadbankondersoek plaaslike omgewingskriteria bestudeer, beginnende met 'n ondersoek na saadbank- en plantegroeihabitats. Chemiese en fisiese eienskappe van grond vanaf twee en twintig terreine op en van Tafelberg af is beskryf. Omvattende grondhabitatwisseling tussen die kruin, die noordwestelike hange en die vlaktes en die suidoostelike hange en vlaktes van Tafelberg is geïdentifiseer. Mikroterreinwisseling tussen die oop-dak (tussenplantruimtes) en toe-dak (onderplantdekking) -mikrohabitats is as beduidend bevind. Primêre grondhabitatverskille is gekoppel aan die inhoud van die grond se organiese materiaal, wat op die vlaktes as laag bevind is vergeleke met die kruin en hange; en laag bevind is in oop-dak-mikroterreine vergeleke met toe-dak-terreine, Daar is gevind dat die grondtekstuur en voedingstofsamestelling op en van Tafelberg af aansienlik varieer, met beduidende verskille tussen die kruin en die vlaktes, en ook tussen die noordwestelike en suidoostelike vlaktes. Daar is gevind dat die hange intermediêr is (toon 'n mate van gradiënt) tussen die kruin en die vlaktes. Die wisseling in grondvoedingstowwe is vertolk as 'n funksie van teksturele en ouermateriaaleienskappe van grond. Antropogeniese faktore vir versnelde erosie, neerslag, loging en soutkorsvorming is ook oorweeg. Die gevolgtrekking is gemaak dat terwyl die eienskappe van grond op en van Tafelberg af inherent aan ouergrond verwant is, kan veranderinge aan tekstuur en voedingstofeienskappe voorkom, en hierdie veranderinge kon deur hoë vlakke van weiding vererger gewees het. 'n Ondersoek (wat op klein struike gefokus het) van plantfenologiese reaksie met betrekking tot reënval en weidingsgradiënte het tendense van piekbot- en blomseisoene na reënval gedurende die somer en herfs onderskeidelik geïdentifiseer. 'n Kontinuum van saadskietaktiwiteit, met piektye in laat herfs en vroeë winter, is van kwartaallikse data saamgestel. Groeistuwing is vir die meeste klein struike waargeneem gedurende lente-, herfs- en someropnames. Aangesien die een of ander vorm van aktiwiteit met betrekking tot voortplantingsgroei (groeistuwing, bot, blom of saadskiet) op feitlik al die tye van die jaar sigbaar was, word daar geredeneer dat hoëintensiteitversteuring (ook weiding) 'n negatiewe impak op plantoorlewing kan hê, wat sal lei tot verminderde voortplantingsinset (m.a.w. sade) in toekomstige geslagte. Plantgemeenskappe op die kruin en vlaktes word beskryf met beduidende verskille tussen plantegroei op die kruin van Tafelberg (wat hoofsaaklik bestaan uit hoëproduksie, smaaklike gras- en struikspesies) en dié ap die vlaktes (wat bestaan uit hoofsaaklik doringagtige, efemere, toksiese en laeproduksie-spesies). Gegee die hoë weidingsdruk op die vlaktes (vergeleke met die minder benutte hange en kruin van Tafelberg), word verskille in die samestelling van plantegroei bespreek met betrekking tot studies elders wat beskadigde weiveld beskryf. Die gevolgtrekking word eerstens gemaak dat die vlaktes om Tafelberg beskadig is, tweedens dat langtermyn-oorbenutting die samestelling van die plantegroei verander het, en laastens dat interweiding-rusperiodes van drie tot ses maande alleen dalk nie die diversiteit van plantegroei of die verlangde plantspesies op die vlaktes kan herstel nie. Die uitslae van kiemingstoetse (wat ondersoek ingestel het na grond-bewaarde saadbanke) van twee steekproefepisodes (lente en herfs 1'998)het getoon dat saadbanke in grond wat van die vlaktes, hange en kruin van Tafelberg verwyder is, die verspreidingspatrone volg wat in bogrondse plantegroei waargeneem is. Spesie-spesifieke data is nie vir hierdie tesis gefinaliseer nie, aangesien nie alle saailinge binne die gegewe tydsbeperkinge gegroei en geblom het nie. Ten einde saailing-verskyningsdata te vergelyk, is plantkategorieë ontwikkel wat efemere en langdurige (meerjarige) spesies en dikotiele spesies en grassoorte en ander monokotiele plante onderskei. Steekproewe van die kruin en teen die middelste en boonste hange het 'n hoë persentasie van aanvaarbare en standhoudende gras- en struikspesies getoon wat in grond-bewaarde saadbanke teenwoordig is, terwyl meer as twee derdes van plante wat in die vlaktes se grondmonsters ontkiem het, efemere spesies was, en die meeste daarvan was klein «5cm) en met 'n kort leeftyd «3 maande). Die meeste van die meerjarige spesies wat van die vlaktes se steekproewe kom, was saailinge van Pentzia incana, Chrysocoma ciliata en vetplante (hoofsaaklik Mesembryanthemaceae), maar min meerjarige grasse was teenwoordig. Daarenteen was onderskeidelik ongeveer 94% van saailinge wat van monsters van die kruin en 63% van saailinge wat van twee van die hange van Tafelberg ontkiem het, langdurige gras- of struikspesies. Ongeveer 89% van die efemere spesies wat van die hange se steekproewe aangeteken is, het op die laagste voethang-terreine ontkiem. Saaddigthede toon 'n noue verband met mikrohabitats, met ongeveer drievoudige verskille tussen oop- (laer saaddigtheid) en toe-dak (hoër saaddigtheid) -mikroterreine. 'n Multivariaatontleding van variansie (MANOVA) het aangedui dat die meeste van die variasie in saaddigtheidsdata op die mikrohabitat-vlak verduidelik is. Seisoenaliteit het 'n sekondêre rol gespeel, met beduidende tweerigting-interaksie tussen die twee uitwerkings. Die gevolgtrekking word gemaak dat albei faktore oorweeg moet word wanneer herstelprogramme ontwikkel word wat ten doel het om algehele plantbedekking en die diversiteit van verbeterde plantspesies te verhoog. Terwyl die oorspronklike of "ongerepte" toestand van die plantegroei se samestelling en saadbanke op die vlaktes onbekend is, is kommer uitgespreek oor die klaarblyklik beskadigde toestand van die totale bo- en ondergrondse plantdiversiteit op hierdie vlaktes. 'n Waarskynlike gevolg van habitatbeskadiging is dat spesies met spesifieke grond-, voedingstofverhouding-, aspek- en seevlak-vereistes van die kruin en hange van Tafelberg (asook van nabygeleë vlakteskuilings) nie in staat sal wees om in beskadigde habitats op die vlaktes te vestig nie. Die identifikasie van pionierplantspesies (verdraagsaam vir habitatbeskadiging) wat verhoogde plantegroeidekking en veilige terreine vir saailingontkieming van verlangde plantspesies toelaat, word aanbeveel. Herstelprogramme sal gekoppel moet word aan streng weidingsbeginsels wat saailingontkieming, die vestiging en suksesvolle voortplantingsproduksie van gewenste plante vir toekomstige weiveldherstel moontlik maak. Algemene en belangrike eienskappe van die grondhabitat, plantfenologiereaksie en kiemingsproefondersoeke word saamgevoeg in 'n ondersoek van habitats en verwante saadbankdiversiteit op en van Tafelberg af. Met erkenning van die kortstondigheid van hierdie navorsingsondersoek, maar met benutting van gevallestudies van elders en die integrasie van albei vraaglyne, word daarweertot die slotsom gekom dat die vlaktes om Tafelberg beskadig is deur dekades en waarskynlik eeue se beweiding deur mak lewende hawe. Dit word as uiters belangrik beskou dat herstel deur verbetering (of rehabilitasie) van habitats en 'n groter aantal saailing beveiligingsterreine oorweeg moet word. Dit lyk asof klimaat sowel as weidingsbestuur 'n onherroeplik gekoppelde rol speel in die vorming van die samestelling van plantegroei op weiveld. Terwyl weiveld intrinsiek aangepas is by die oorlewing van uiterste klimaatswisseling wat in nie-ekwilibriese streke aangetref word, word daar geredeneer dat die impak van beweiding, veral gedurende droogtetye en klimaatsverandering, stadigaan die intrinsieke "buffervermoë" van weiveld verminder om hierdie veranderinge en uiterstes te weerstaan. Dit blyk uit navorsing elders dat herstel deur passiewe bestuur stadig en waarskynlik nie ekonomies haalbaar is binne 'n lewensvatbare tydsraamwerk nie. Die instelling en bevordering van geïntegreerde en strategiese programme wat kwessies van grondbeskadiging en verandering van grondgebruik in semi-droë gebiede identifiseer en oplos, word aanbeveel. Die insette en pogings van verskillende owerhede en ministeries en deelname deur die breë publiek word aangemoedig in hierdie voorgestelde programme ten einde insette met 'n breë basis in die langtermyn~volhoubaarheid en bewaring van die aansienlike biologiese diversiteit van hierdie streke te verseker. Saadbankbeoordeling word beskou as 'n waardevolle manier om die herstelpotensiaal en weiveldtoestande met die potensiaal vir die identifisering van beskadigde sowel as bewaringswaardige gebiede aan te dui. Laastens word 'n paar beperkings en uitdagings van hierdie studie ondersoek deur 'n proses van eerstens die identifisering van alternatiewe benaderings tot navorsingsmetodologieë, en tweedens deur die voorstel van aanbevelings vir toekomstige navorsingsprojekte. Terwyl alternatiewe metodes toegepas kon gewees het ten einde hierdie studie af te handel, is die gevolgtrekking dat die toepaslike metodes binne die gegewe tyd5- en ander beperkings toegepas is.

Thesis (MSc (Earth Sciences))—University of Stellenbosch, 2005.
The integration of whole-rock chemistry, heavy mineral chemistry, detrital zircon morphology and age dating has enabled high-resolution characterization of the Permian Laingsburg and Tanqua submarine fan provenance in the Karoo Basin, upper Ecca Group, South Africa. Geochemically, the Laingsburg and Tanqua sandstones are classified as greywacke and litharenite. The chemical index of alteration values for these sandstones suggest low to moderately weathered sources and a relatively cold climate. Abundant angular clastic grains and lithic fragments as well as the predominance of pristine zircons indicate a near provenance and a first cycle derivation. The investigated sandstones originated from a continental island arc and an active continental margin. The source is dominantly intermediate to felsic and includes tonalites, granodiorites, and adamellites or their volcanic equivalents.

Degradation in the Sneeuberg Region of the central Karoo, South Africa is characterized by the development of badlands on the footslopes of upland areas and by gully systems in valley bottoms. Degradation also occurs on formerly cultivated valley bottom land. Climatic and management factors have been suggested as the predominant drivers behind what is perceived by farmers as degradation (Acocks, 1953, Hoffman et al. 1999). The main thesis question is which factors have predominated in producing the erosional features observed in the study area?

Thesis (DPhil (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The Karoo Array Telescope (KAT) will be used by South Africa in its bid to host the international Square Kilometre Array (SKA). As the SKA will have orders of magnitude greater sensitivity than existing radio telescopes, it will also be concomitantly more sensitive to radio frequency interference (RFI). The influence of RFI on a differential mode (DM) KAT conductive system is an unavoidable phenomenon. In this context, the conductive or galvanic system can, in its most basic form, consist of a source, a load, and connecting conductors. It can also, in the case of the KAT-7 seven-dish interferometer, consist of each telescope, its functional cabling, and the main correlator connecting the telescopes together. However, additional connections between the system and the environment exist. These might be an intentional connection made to the earthing layout, or unintentional connections due to parasitic capacitances and inductive connections. As a result of this, additional conductive systems are created which carry common mode (CM) currents. Interference present in such CM paths enters the DM system through the transfer impedance (Zt) between them. To reduce or eliminate this interference in the DM system, Zt has to be minimised. The use of an earthed parallel conductor (EPC as commonly referred to) in the form of a cable tray is considered to be one of the principal methods to reduce Zt. The properties of cable trays as EPCs at wavelengths which are greater than the tray length are well documented. One main focus in this dissertation is on cable tray mid-span and end connections. They are not well described in the literature over the wide range of frequencies that is expected for KAT developments. The influence of the most common connections on the measured and computed Zt of the cable tray is determined. Computer Simulation Technology’s Microwave Studio (CST MWS) is employed to validate the measured results and also to enable visualisation of the fields and currents. Recommendations for the best connection to use for any cable tray installation is given. The overall shielding ability of optimally-connected cable trays has been evaluated using a physical and computational model. In both cases the induced voltage on a victim conductor, and far-field gain functions for varying angles of incidence onto the model, are determined. The results also show that for certain scenarios, most of the coupling to the victim conductor, takes place inside the end enclosure and not the cable tray. In general, properly-connected cable trays do provide protection to their enclosed conductors, even at frequencies were the wavelength is much shorter than the width of the tray. The second main focus arises from an on-site radio frequency (RF) current audit undertaken on two of the seven KAT-7 telescopes. Shielding measures, such as interface barriers at the floor and roof of the lower telescope pedestal, are studied. The investigation is facilitated by the development of an accurate physical and computational scale model of the dish. Direct current injection and plane wave illumination methods are used to excite the system. The measured CM current distributions are compared and comments made regarding the validity of the measurement procedure. The CM currents, measured around the outside of the lower pedestal show higher levels when a direct current path to ground is established, as opposed to when no clear path exists. This finding suggests at least two methods of preventing CM interference entering or leaving the pedestal: harden the floor and roof barriers, or manage current paths outside the telescope. Related to this, CM currents measured either side of the telescope interface barriers, are used to determine the level of shielding the interface provides. When compared to the common definition of shielding effectiveness, the current measurement provides more conservative shielding estimates. The research in this dissertation has influenced, and will continue to influence, the layout of galvanic systems for the present KAT-7 structures and the anticipated developments to MeerKAT.
AFRIKAANSE OPSOMMING: Die Karoo Array Telescop (KAT) sal gebruik word deur Suid-Afrika in sy poging om die bod te kry om die internasionale Square Kilometre Array (SKA) te huisves. Aangesien die SKA ordes meer sensitief sal wees as bestaande radioteleskope, sal dit terselfdertyd ook meer sensitief wees vir radio frekwensie steurnisse. Die invloed van radio frekwensie steurnisse op die differentiëlemodus KAT geleidende netwerk is iets onvermydeliks. Binne hierdie konteks kan die geleidende netwerk, in sy mees basiese vorm, bestaan uit ʼn bron, ʼn las, en verbindingsgeleiers. Dit kan ook, in die geval van die KAT-7 sewe-teleskoop interferometer, bestaan uit elke teleskoop, sy funksionele bekabeling, en die korrelator wat die verbinding is tussen al die teleskope. Daar is egter, addisionele verbindings tussen die netwerk en die onmiddellike omgewing rondom dit. Hierdie verbindings kan opsetlik gemaak word deur byvoorbeeld, verbinding van die netwerk se aardkabel aan die res van die beaarding, of onopsetlik deur parasitiese kapasitansies en induktiewe verbindings. As gevolg hiervan word addisionele geledende netwerke geskep waarin gemenemodus strome kan vloei. Indien daar wel strome in die gemenemodus netwerk vloei, word dit oorgedra aan die differentiëlemodus netwerk deur ʼn oordragimpedansie (Zt) wat teenwoordig is tussen die twee. Om dus die steurnisse in die differentiëlemodus netwerk te verminder of te elimineer, moet Zt tot ʼn minimum beperk word. Die gebruik van ʼn geaarde parallelle geleier in die vorm van ʼn kabelkanaal, word beskou as een van die mees doeltreffendste metodes om Zt te verminder. Die eienskappe van kabelkanale as geaarde parallelle geleiers by frekwensies waar die golflengtes langer is as die van die kabelkanaal, is volledig gedokumenteer. Een van die belangrikste fokuspunte in hierdie verhandeling is rakende die kabelkanale se middel en eindpuntverbindings. Hulle word nie goed beskryf in die beskikbare literatuur nie, en weliswaar vir wyeband doeleindes wat vir KAT ontwikkelinge verwag word. Die invloed van die mees algemeenste kabelkanaal verbindings op gemete en berekende Zt word bepaal. Computer Simulation Technology’s Microwave Studio (CST MWS) word eerstens, gebruik om die akkuraatheid van die gemete resultate te bewys en tweedens, deur visualisering van E-veld en gemenemodus oppervlak strome. Aanbevelings vir die beste verbindings vir enige kabelkanaal opstelling word gegee. Die algemene afskerminsvermoeë van ʼn idiaal-verbinde kabelkanaal word bepaal deur middel van metings en simulasies. In beide gevalle word die geïnduseerde spanning op ʼn slagoffer kabel, en die verveld aanwins funksie bepaal vir verskillende invalshoeke op die model. Die resultate toon verder dat vir spesifieke gevalle wat beskou word, die meeste koppeling binne die kabinet aan die einde van die kabelkanaal plaasvind. Oor die algemeen verskaf goed verbinde kabelkanale wel ʼn sekere vlak van beskerming aan kabels binne die kabelkanaal, selfs by frekwensies waar die golflengte baie korter is as die breedte van die kabelkanaal. Die tweede belangrike fokuspunt spruit voort uit ʼn radio frekwensie stroomoudit, wat twee van die KAT-7 teleskope evalueer het. Afskermingsmatreëls soos die kabelhindernisse op die vloer en dak van die onderste teleskoop voetstuk, word bestudeer. Tesame met die metings op die werklike teleskoop wat geneem is, word ʼn akkurate fisiese en simulasie skaalmodel geskep om die metings beter te analiseer. Direkte stroominspuitings metode en platvlakgolf beligting word gebruik om gemenemodus strome op die teleskoop se struktuur te induseer. Die gemenemodus stroomverspreiding vir beide tegnieke word vergelyk in ʼn poging om kommentaar te lewer rakende die geldigheid van die meettegniek. Die gemenemodus strome wat aan die buitekant van die teleskoop voetstuk gemeet word, is hoër wanneer ʼn direkte stroompad na grond op die voetstuk geskep word in vergelyking met ʼn ongedefinieerde pad. Hierdie verskynsel dui daarop dat ten minste twee metodes bestaan om die ongevraagde gemenemodus strome te verhoed om aan die binnekant van die teleskoop voetstuk te vloei. Die een is die verbetering van die vloer en dak kabelhindernisse, en die ander is verbetering van die stroompad (stroompaaie) aan die buitekant van die voetstuk sodat ʼn meer direkte pad na grond geskep word. Die gemiddelde gemenemodus strome weerskante van die kabelhindernis, kan gebruik word op te bepaal hoeveel afskerming die hindernis bied. Indien die berekende waardes by verskillende frekwensies vergelyk word met die tradisionele filter doeltreffendheid (Zt), word ʼn meer konserwatiewe beraming verkry. Die navorsing in hierdie verhandeling het alreeds, maar sal ook die toekomstige uitleg van galvaniese stelsels vir KAT-7 asook die verwagte MeerKAT beïnvloed.

Les provinces magmatiques continentales géantes (CFB) sont des événements clefs dans l’histoire de la terre, souvent associés à la dislocation des continents et des crises biologiques majeures. La province magmatique de Karoo-Ferrar est l’un des CFB majeur du Phanérozoïque avec des affleurements présents en Afrique méridionale, en Antarctique et en Australie. Sa formation datée du Jurassique inférieur est liée à la séparation de l’Afrique et de l’Antarctique et à l’ouverture de l’Océan Indien. Le magmatisme du Karoo (Afrique méridionale) s’étend sur plus de 3x106 km² et est généralement considéré comme étant un événement bref (184 ± 1 Ma) associé à un point chaud et un rifting de type «actif». La présente étude porte sur la géochronologie 40Ar/39Ar et la géochimie élémentaire et isotopique (Sr, Nd, Pb et Hf) de zones peu ou pas étudiées. Cette étude a été focalisée sur 1) les coulées et sills basaltiques du Botswana, (2) les réseaux radiaires géants de dykes mafiques supposés représenter une jonction triple et (3) les plutons et dykes représentant le stade final du magmatisme. Ces données nous ont permis de mettre en évidence les points suivants : I) Les réseaux de dykes de l’Okavango (N110°; 1500x100 km) et du Sabie-Limpopo (N70°; 600x50 km) ont donné 18 âges similaires dont la moyenne est de 179. 1 ± 1 Ma. Ce résultat s’accorde avec les données structurales montrant un événement distensif unique (N160°) pour la structuration de ces réseaux. En revanche, les coulées du Botswana se sont mises en place sur une période plus longue, avec des âges plateau allant de 182 à 177. 5 Ma (27 ages). Nos âges, comparés à ceux obtenus au sud de la province (185-181 Ma), montrent une migration des zones d’éruption du sud et de l’est vers le nord ouest ainsi qu’une durée du magmatisme supérieure à 6 Ma. Ces données impliquent une origine différente comparées aux autres provinces dont les durées de mise en place sont généralement brèves (1 Ma). De plus une longue durée pourrait expliquer l’absence d’extinction faunistique majeure. L’étude du magmatisme intrusif à l’est de la province montre qu’une activité magmatique plus différenciée s’est poursuivie près du (futur) rift jusqu'à 174 Ma, suivie par l’intrusion des dykes du réseau Rooi Rand (174-172 Ma) dont l’affinité chimique (E-MORB) suggère un lien avec l’ouverture de l’Océan Indien. II) La découverte de dykes Protérozoïques (issus du CFB Umkondo ?) au sein de trois (et peut être quatre) réseaux formant le fameux « point triple », démontre que ces directions majeures sont antérieures au magmatisme Karoo. Ceci infirme une origine « point chaud Karoo » pour ces structures et suggère plutôt un contrôle du magmatisme par des zones de faiblesse lithosphériques préexistantes. III) On identifie deux groupes géochimiques, pauvre et riche en Ti, tous deux enrichis en LILE/HFSE, mais différant par leur fractionnement en terres rares lourdes et leur composition isotopique. Les deux groupes ont évolué par fusion partielle de lherzolites à spinelle (« low-Ti ») ou à grenat (« high-Ti ») puis par cristallisation fractionnée d’assemblages gabbroïques. Les deux groupes sont issus d’un manteau lithosphérique sous-continental (SCLM) hétérogène, enrichi de veines métasomatiques (sédiments subductés ?) pour certains des magmas riches en Ti (notamment les picrites). Ces différences géochimiques reflètent l’histoire de la lithosphère dont les hétérogénéités latérales et verticales contrôlent la distribution des deux groupes. La signature chimique d’un panache mantellique n’a pas été identifiée. A partir des arguments géochronologiques, structuraux et géochimiques présentés dans ce mémoire, le CFB du Karoo, à la différence d’autres CFB, ne requièrent pas la contribution d’un point chaud, mais souligne le rôle prépondérant de la lithosphère, par son histoire et sa structure, dans la genèse des magmas
The continental flood basalts (CFB) represent key-events in the Earth history and are generally associated with continental break-up and major biotic extinctions. The Karoo-Ferrar lower Jurassic magmatic province is one of the largest CFB and outcrops in southern Africa, Antarctica and Australia. It is related to the separation between Africa and Antarctica and the opening of the Indian Ocean. The Karoo magmatism is located in southern Africa and stretches over more than 3x106 km². It is generally considered as a brief event (184 ± 1 Ma) associated with a mantle plume head and subsequent “active” rifting. This study concerns the 40Ar/39Ar geochronology and elemental and isotopic (Sr, Nd, Pb and Hf) geochemistry of poorly studied areas. We particularly focused on (1) the basaltic lava-flows and sills of Botswana (2) the giant radiating dyke swarms (so-called “the triple junction”) and (3) the late-stage plutons and dykes. These data permit to illustrate the following points: I) The 18 ages obtained on the giant Okavango (N110°; 1500x100 km) and the Sabie-Limpopo (N70°) dyke swarms show a mean age of 179. 1 ± 1 Ma. These results are in agreement with the structural data suggesting a broad NW-SW extensional event for both dyke swarms. On the other hand, Botswana lava-flows were emplaced over a larger period with most ages ranging from 182 to 177. 5 Ma (27 ages). Our ages compared to those obtained in the southern and eastern zone (185-181 Ma) suggest a northwestward migration of the magmatism and province duration greater than 6 Myr. These data show that the Karoo province is peculiar compared to other short-lived CFB considered to be related to a mantle-plume arrival. Such a long duration may explain the absence of important biotic crisis generally reported for other CFB. The investigation of differentiated magmatism suggests that the Karoo province was still active up to 174 Ma, close the future rifted zone. At 174-172 Ma, the emplacement of the MORB-like Rooi Rand dyke swarm is likely to represent the onset of the Indian Ocean opening. II) We show that the occurrence of Proterozoic dykes into three (and may be four) branches of the “triple-junction” demonstrate that the dyke directions clearly pre-date the Karoo magmatism. This confirms that the radiating structures were not induced by the arrival of a mantle plume but rather acted as lithospheric weakened paths which likely canalized the Karoo magmatism. III) On the basis of geochemical composition, we identify two groups (the low- and high-Ti rocks) both showing enrichment in LILE/HFSE but having different REE fractionation and isotopic composition. Both groups evolved by melting of spinel-bearing (low-Ti) and garnet-bearing (high-Ti) enriched lherzolites and by subsequent fractional crystallization of gabbroic assemblages. The low- and high-Ti magmas were issued from a heterogeneous and partially metasomatically veined (mainly for some high-Ti rocks and picrites) sub-continental lithospheric mantle (SCLM). Such geochemical differences illustrate the vertical and horizontal distribution of the lithosphere heterogeneities. No evidence of a deep seated mantle plume has been detected. The Geochronological, structural and geochemical data show that, contrary to some other CFB, the Karoo province does not require a deep mantle plume contribution but highlight the prominent role of the lithosphere in the Karoo genesis and emplacement

This thesis focuses on vegetation patterns and plant reproductive processes at the Tierberg Karoo Research Centre (33°1 0'S, 22°17'E) in the semi-arid southern Succulent Karoo, South Africa. It begins with an investigation into the roles of soil properties and competition in explaining variation in species distributions. The aim was to investigate changes in soil properties associated with species turnover (replacement series). Patterns of species abundances have been attributed to cyclic succession driven by disturbance and inter-specific competition. Areas where dominant species replaced each other over apparent edaphic discontinuities were investigated to test the roles of soil properties and competition in explaining variation in species distributions. Only soil pH differed significantly across the gradients studied. However, inter-and intra-specific· competitive interactions were also inferred. It was concluded that species distribution patterns resulted from the combined effects of edaphic factors and competition. The bulk of the thesis focuses on the reproductive biology of key species in the cyclic succession in order to understand the demographic processes underlying these patterns. The vegetation model proposes that heuweltjies (or mima-like mounds) are the source of disturbance which initiates the successional process. A study of reproductive attributes of dominant species occurring on and off heuweltjies indicated that species occurring on heuweltjies had opportunistic life-history traits; seeds did not germinate readily and canopy seed banks were maintained. Species off heuweltjies had higher overall germination and did not maintain seed banks in the plant canopies. The differences in reproductive attributes were related to competition and disturbance.

Fencing, particularly electric fencing, is widely used across South Africa for livestock and game ranching practices. Recent studies found that leopard tortoises (Stigmochelys pardalis) are more prone to dying from electrocution along electric fences than any other taxa. However, no studies have quantified tortoise mortality along non-electric fences or assessed the impact of fence structure. With South Africa being home to more tortoise species than anywhere else in the world, thus is a conservation concern. This study quantifies tortoise mortalities associated with electrified and non-electrified fences and relates these rates to fence structure (mesh or strand). Open veld transects are used as controls to estimate background mortality. This study also reports the distribution and abundance of different fence types along 2200 km of roads in the southeastern Karoo, allowing the cumulative impacts of different fence types to be estimated. All fence types had significantly higher tortoise mortalities than open veld transects. Leopard tortoise mortalities were significantly higher along electric fences than non-electric fences. Despite forming only approximately 4% of all roadside fencing, electric fences account for 56% of leopard tortoise mortalities. This study validates concern for increased electric fence use in the future and the potential impacts on leopard tortoises. When considering the current abundance of fence types and their associated mortalities, the total number of leopard tortoise mortalities along electric and non-electric fences are similar. Angulate tortoise (Chersina angulata) mortalities were significantly higher along mesh fences than strand fences, but did not differ between electric and non-electric fences. Angulate tortoises appear to wedge themselves in mesh fences and are unable to escape. This study highlights the current threat of non-electric fencing on tortoises as no similar findings have been reported. These additional tortoise mortalities should be considered alongside other emerging threats when questioning the longevity of these tortoise populations, not only in the Karoo, but globally. The implementation and practicality of previously suggested mitigation strategies are discussed and alternative mitigation strategies are suggested. This study concludes that raising of the electric strands is impractical and the implementation of rock aprons are ineffective. Live tortoises displayed active behavior when temperature was above 20 °C, thus thermostatic switches for electric fences could potentially reduce tortoise mortalities without compromising fences function.

This minor dissertation is based on fieldwork conducted for the Institute for Intercultural and Diversity Studies (iNCUDISA) at the University of Cape Town's Rural Transformation Project. The focus is on the investment in 'white benevolence' in a small Karoo (Northern Cape) town and in ways that white residents present themselves, and position themselves discursively, as benevolent whites. Loosely located in social constructionist and postmodernist paradigms, this piece of work also attempts to illustrate how lived experience and the situatedness of subjectivity impact on the research experience and the subjectivity of the 'researcher.' Ultimately, it is posited that if we are interested in the nature and extent of social transformation, the question of subjective transformation must be considered.

The primary aim of this study was to determine who claims the corbelled buildings in the Karoo as their heritage and why. Through the use of vernacular architecture and heritage identification theory, interviews and research it is clear that the buildings are significant and a heritage resource. Their significance lies in their historical, social, aesthetic, symbolic and cultural values, as well as their unique vernacular construction and limited distribution. The corbelled buildings as vernacular buildings are part of the natural landscape which the local community associate as part of their identity and heritage. The buildings also possess academic and historical potential as they have the potential through further archaeological and vernacular architectural research, to provide more information on the northern frontier during the late 18th and early 19th centuries, a time that is not well recorded or documented. The buildings were built in 19th century along the ‘open’ northern frontier where there was intermingling and creolisation of people from different economic and social groups. As a result, they cannot be claimed by a single group of people in the present. The vast range in types and styles of corbelled buildings indicate that they were built by most people living in the area. They can therefore, be claimed by everyone who lives in the area today. They can also be claimed as national heritage as they possess values that are common to the whole country.

Includes bibliographical references (leaves 99-106)
This dissertation takes its lead from the need to add to the debate issues of institutional arrangements when evaluating the effectiveness of biodiversity conservation programs. The particular case in point is the Succulent Karoo Ecosystem Program (SKEP), which was initially set up by a NGO, Conservation International (CI), and thereafter transferred to another host institution, a national parastatal called the South African National Biodiversity Institute (SANBI). This dissertation set out to investigate the optimal institutional mechanism for coordinating SKEP. in light of its transition from CI to SANB!. This was done by evaluating the current coordination mechanism. A systems theory approach guided the research. An action research approach ensured that the results would be practical to the coordination unit of the SKEP program. Grounded theory analysis was used to analyze and make sense of the data and provide guidance on the functions and structure of the coordination unit and its supporting structures.

The New Amalfi Sheet is a highly differentiated tholeiitic intrusion which is situated between the towns of Matatiele and Swartberg in East Griqualand. It lies within the Central area of the Karoo Igneous Province. Rock types range from dolerites at the base and top through to a highly differentiated granophyre which is found as a 'sandwich horizon' within the top half of the sheet. The most evolved granophyre represents 15.86% of the initial liquid, which was found to be very similar in composition to the average Lesotho-type magma of Marsh and Eales (1984). The paragenetic sequence was found to be chromite → olivine → plagioclase → pigeonite and augite. Cumulus magnetite and ilmenite enter the paragenetic sequence together with immiscible sulphide droplets after 35% crystallization. In the late stages of crystallization, augite changes composition towards ferrohedenbergite. The reappearance of iron-rich olivine coincides with the disappearance of pigeonite and apatite appears as a cumulus phase for the first time after 70% crystallization. Granophyric intergrowth, which contains coarse perthitic Kfeldspar, becomes the most abundant modal entity within the most evolved granophyres. Differentiation was dominated by fractionation of plagioclase and pyroxene, with subordinate olivine and opaque-oxide fractionation. A minor amount of assimilation of country rock occurred within the topmost granophyres. The intrusion has been dated, using the Rb-Sr isochron method, at 178.37 ± 5.52 Ma. Extensive subsolidus deuteric alteration has resulted in the formation of a complete series of hydrothermally altered clinopyroxenes which are enriched in CaO but depleted in TiO₂ compared to the unaltered magmatic clinopyroxenes. It has also resulted in the formation of abundant vermiform ilmenite in the most evolved rocks, recognized by the fact that this phase is enriched in MnO compared to magmatic ilmenites. The very iron-rich orthopyroxene, ferrohypersthene, was found to have crystallized, during cooling of the sheet from the intercumulus liquid. Olivine in the dolerite re-equilibrated with the intercumulus liquid, becoming more iron-rich in composition.

Gabbroic rocks in sills commonly display well organized magnetic fabrics that are generally attributed to magma flow. Yet in a number of cases, magnetic fabrics that are considered proxies for flow fabrics, form at a high angle to the intrusive - host rock wall. A symmetrical oblique magnetic fabric observed in opposite margins of a dike has been interpreted as the result of viscous drag against the margin, a model referred to as fabric imbrication. In this study tested if a similar viscous drag model could also apply to sills. The Karoo Large Igneous Province (LIP) of South Africa offers unparalleled opportunities to investigate fabrics, internal zonation and magma flow in mafic sills of thicknesses ranging from 5 to 50 m. Exceptionally; Karoo sills can reach a 1000 m in thickness (e.g., Insizwa). Geochemical studies suggest that the Karoo gabbro sills have a consistent tholeiitic magma composition across the entire Karoo Basin, especially as far as major elements are concerned. It is also practically undeformed and upon initial inspection unweathered, making it a well suited natural laboratory to test fabric models in gabbro sills. Magnetic fabrics are generally considered a good proxy for magmatic fabrics. The anisotropy of magnetic susceptibility has been measured on oriented hand specimens collected across vertical profiles through two representative sills. Scalar parameters such as magnetic susceptibility, degree of anisotropy and shape factor show variations with height in the intrusion. The variations in these parameters can be interpreted in terms of magmatic dynamic and static processes such as, for example, thermal convection, gravitational crystal settling or magmatic mush compaction. Directional parameters provide additional constrains on the dynamic vs. static nature of fabric-forming processes. Petrographic studies indicate that the primary carrier of the magnetic properties of the Karoo gabbros is titanomagnetite. Accessorily, pyrrhotite and hematite are present, but not in sufficient quantities to account for more than 1% of the sampled intrusions magnetic properties. Hydrous phyllosilicates are present in one sample, suggesting some alteration has occurred at the upper contact of the Country Club Road sill. Magnetic fabrics of the studied sills reveal complex susceptibility and remanence fabrics as a function of stratigraphic height. The proposed fabric development model does not sufficiently describe the observations, thus these fabrics were formed by a combination of mechanisms, both early and late in the cooling history of the intrusions. The observed magnetic fabrics display properties consistent with both the fabric imbrication model and the proposed viscous shear model. It is possible that crystal settling, melt segregation and possibly convection processes also were likely integral to the formation of the magnetic fabrics of the studied Karoo sills, though further studies are necessary.

Leopards (Panthera pardus) are the most common large predators, free roaming outside of protected areas across most of South Africa. Leopard persistence is attributed to their tolerance of rugged terrain that is subject to less development pressure, as well as their cryptic behaviour. Nevertheless, existing leopard populations are threatened indirectly by ongoing transformation of natural habitat and directly through hunting and conflict with livestock farmers. Together these threats may further isolate leopards to fragmented areas of core natural habitat. I studied leopard habitat preferences, population density, diet and the attitudes of landowners towards leopards in the Little Karoo, Western Cape, South Africa, an area of mixed land-use that contains elements of three overlapping global biodiversity hotspots. Data were gathered between 2010 and 2012 using camera traps set up at 141 sites over an area of ~3100km², GPS tracking collars fitted to three male leopards, scat samples (n=76), interviews with landowners (n=53) analysed in combination with geographical information system (GIS) layers. My results reveal that leopards preferred rugged, mountainous terrain of intermediate elevation, avoiding low-lying, open areas where human disturbance was generally greater. Despite relatively un-fragmented habitat within my study area, the leopard population density (0.75 leopards/100km²) was one of the lowest yet recorded in South Africa. This may reflect low prey densities in mountain refuges in addition to historical human persecution in the area. Currently local landowners are more tolerant of leopards than other wildlife species with incidents of conflict involving leopards being rare relative to black-backed jackals (Canis mesomelas), baboons (Papio hamadryas), caracals (Caracal caracal) and porcupine (Hystrix africaeaustralis). Although current levels of conflict between leopards and stock farmers are low, leopards do depredate livestock, which constitute 10-15% of their diet. Improved livestock husbandry measures and co-operation between conservation authorities and farmers are necessary to mitigate such conflict and balance economic security with biodiversity conservation in the region. Leopards are the only remaining top predators throughout much of the Little Karoo and the Western Cape and as such are predicted to play a critical role in ecosystem structure and the survival of other species. Current high levels of connectivity between areas of suitable leopard habitat bode well for the conservation status of leopards within this region and future conservation efforts need to ensure that narrow corridors linking such habitat are preserved. The potential for leopards to serve as both an umbrella and a flagship species for biodiversity conservation suggests that long term monitoring of this population would be a conservation priority for the Little Karoo.

Thesis (MA)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The succulent thicket plant community of South Africa, particularly Portulacaria afra (in this study referred to as spekboom), occurring in the Thicket Biome, sequestrates an exceptional amount of carbon dioxide (due to its photosynthetic properties), particularly for a warm, semi-arid region and in this capacity is more akin to forest ecosystems. Spekboom has additional favourable characteristics over forested systems regarding carbon trading (CT), namely: economic water use; potential for combating desertification and poverty in arid environments; and ability to withstand stand-replacing fire (spekboom doesn’t burn) which improves its attraction as a commodity in CT and the payments for ecosystem services (PES) industry. Landowners interested in using the capacity of their land for carbon sequestration (CS) are challenged to calculate their plant communities’ sequestration ability and biodiversity potential and therefore to quantify the carbon credits to be sold. The aim of the study was to quantify the CS ability of a selected property unit by vegetation area and to establish the carbon credits value that can be sold in the carbon market. It commenced by highlighting the problem of global warming and its effect on climate change in South Africa. CS is described as a process and a solution to decrease high and rising atmospheric CO2 levels, and its use in the carbon market to attain a monetary value to promote the growing of vegetation or to protect and conserve biodiversity that will enhance carbon stocks. The study site is Bosch Luys Kloof Private Nature Reserve (BLK PNR) in the semi-arid Karoo. Because CS potential is known to follow a rainfall gradient, one expects the semi-arid Karoo to have a low CS potential. However, this area contains spekboom, an extraordinary thicket type that sequestrates carbon at similar rates to forest ecosystems and should therefore reap the benefits of CT. Yet, accurate mapping of this vegetation is critical for accurate carbon stocks assessment. The CS potential of all vegetation communities in the study area had to be established to estimate the carbon stocks in the whole property unit. ArcGIS was used to map the vegetation communities (sub biomes) and eCognition to refine mapping of the Gamka Thicket (containing spekboom) through an object-orientated approach to automated vegetation mapping. For accuracy assessment a heads-up digitized map was created for comparison. The true surface area was calculated for the vegetation classification to ensure accurate area accounting on the mountainous terrain and this calculated area of the mapped vegetation was used to convert area to carbon sequestration potential. By examining the different markets and trading mechanisms for trading in the carbon market, using CS, a marketing strategy for the land units was advised. Results show that due to BLK PNR's history of overstocking, spekboom remains degraded on the study site. This creates an opportunity to restore the vegetation with funding through CT. The sequestration potential of spekboom on BLK PNR was determined through a regional differentiation comparison. The regional differentiation comparison identified that rainfall amount and carbon accumulation are inversely proportional, therefore more arid conditions (<200mm a year, or a dry season longer than seven and a half months) cause spekboom to switch to Crassulacean acid metabolism (CAM) due to water stress, so increasing the rate of carbon accumulation. In wetter environments, where spekboom is not under water stress, it continues in carbon fixation of 3-phosphoglycerate (C3) having a lower carbon accumulation. This is a remarkable finding as CS is known to follow a rainfall gradient: in this instance spekboom is an exception to the norm. Mapped results showed that eCognition classified spekboom poorly, yielding between 64% and 69% correspondence to the accurate manually classified map. As expected three-dimensional area comparative results show that the true surface area on complex terrains was 10% higher than the original (and surveyed) land area of the estate. Results indicate that there are substantial carbon stocks for CT on BLK PNR. This study recommended the most practised form of CT (restoration) for BLK PNR. Over a period of 30 years of restoration on BLK PNR about 46 000 tons of carbon could be sequestrated. At the current price of carbon credits this could accumulate over R3.7 million over the 30-year restoration period. Combining restoration with conservation strategies into one project type has additional favourable characteristics as it takes into account the CS potential of all vegetation communities on the land unit and the ecosystem services it promotes. Conservation of BLK PNR would yield 758 000 tons of carbon. Calculated through emission abandonment, this could be valued at R8-10 million. The economic importance of the vegetation community’s biodiversity on BLK PNR and significant differences between biomes were recorded and implies a total intrinsic value in excess of R830 000 per annum. To date, pilot projects elsewhere have successfully acquired carbon credits for avoided deforestation through the climate, community and biodiversity alliance (CCBA). However, owing to the pilot stage status there is little literature that substantiates the calculation of the monetary value of conservation. This is a fertile area for further research.
AFRIKAANSE OPSOMMING: Die sukkulent-struikplantgemeenskap van Suid-Afrika, in besonder Portulacaria afra (waarna in hierdie studie as Spekboom verwys word), wat in die Struikgewasbioom voorkom, neem ‘n uitsonderlike hoeveelheid koolstofdioksied op (weens die fotosintetiese eienskappe daarvan), veral vir ‘n warm, semi-ariede streek en is in hierdie kapasiteit meer verwant aan woud-ekosisteme. Spekboom het, met betrekking tot koolstofuitruiling (KU) of koolstofhandel, addisionele gunstige eienskappe bo dié van woudsisteme, naamlik lae waterbenutting; potensiaal vir die bestryding van woestynvorming en armoede in ariede omgewings; en die vermoë om brand te weerstaan (Spekboom brand nie), wat sy aantreklikheid as ‘n kommoditeit in KU verhoog, en die betaling vir dienste in die ekosisteem-industrie (BED) verbeter. Grondeienaars wat geïnteresseerd is in die benutting van hul grond vir koolstofopname (KO), word uitgedaag om hul plantgemeenskappe se opnamevermoë en potensiaal vir biodiversiteit te bereken, en gevolglik die hoeveelheid koolstofkrediete wat verkoop kan word, te kwantifiseer. Die doel van die studie was om die KO-vermoë van ‘n geselekteerde eiendomseenheid volgens die oppervlakte onder plantegroei te kwantifiseer en om die waarde van koolstofkrediete wat in die koolstofmark verkoop kan word, vas te stel. Ten aanvang is die probleem van aardverwarming en die uitwerking daarvan op klimaatsverandering in Suid-Afrika uitgelig. KO word beskryf as ‘n proses en oplossing om die hoë en stygende atmosferiese CO2-vlakke te verminder, en die gebruik daarvan in die koolstofmark, om ‘n monetêre waarde te verkry om plantbedekking te bevorder of om biodiversiteit, wat koolstofvoorraad sal vermeerder, te beskerm en te bewaar. Die studieperseel is Bosch Luys Kloof Privaat Natuurreservaat (BLK PNR) in die semi-ariede Karoo. Omrede KO-potensiaal bekend is daarvoor om ‘n reënvalgradiënt te volg, verwag mens dat die semi-ariede Karoo ‘n lae KO-potensiaal sal hê. Hierdie gebied bevat egter Spekboom, ‘n buitengewone struiksoort wat koolstof teen soortgelyke tempo’s as woud-ekosisteme opneem, en behoort daarom voordeel uit KU te trek. Akkurate kartering van hierdie plantegroei is kritiek vir akkurate assessering van koolstofvoorraad. Die KO-potensiaal van alle plantgemeenskappe in die studiegebied is derhalwe vasgestel om die koolstofvoorrade in die totale eiendomseenheid te skat. ArcGIS is gebruik om die plantgemeenskappe (sub-biome) te karteer en eCognition is gebruik om die kartering van die Gamkaruigte (wat Spekboom bevat) deur ‘n objek-georiënteerde benadering tot geoutomatiseerde plantegroeikartering te verfyn. Vir akkuraatheidsassessering is ‘n vergelykbare plantegroeikaart per hand versyfer. Die werklike oppervlakte van die gebied is vir die plantegroeiklassifikasie bereken om akkurate oppervlakberekening van die bergagtige terrein te verseker, en hierdie berekende oppervlakte van die gekarteerde plantegroei is gebruik om oppervlakte na koolstofopname-potensiaal te herlei. Advies oor ‘n bemarkingstrategie vir die grondeenhede is gegee, deur die verskillende markte en uitruilings- of handelsmeganismes vir handel in die koolstofmark te ondersoek. Resultate toon dat weens die BLK PNR se geskiedenis van oorbeweiding, Spekboom op die studieperseel gedegradeer het. Dit skep ‘n geleentheid om die plantegroei met befondsing deur KU te herstel. Die opname-potensiaal van Spekboom op BLK PNR is deur ‘n streeksdifferensiasie-vergelyking bepaal. Die streeksdifferensiasie-vergelyking toon dat hoeveelheid reënval en koolstofakkumulasie omgekeerd eweredig of proporsioneel is, en gevolglik veroorsaak meer ariede omstandighede (<200 mm/jaar, of ‘n droë seisoen van langer as sewe en ‘n half maande) dat Spekboom weens waterstres na Crassulacea-suurmetabolisme (CSM) oorskakel, en sodoende die tempo van koolstofakkumulasie verhoog. In natter omgewings, waar Spekboom nie aan waterstres onderwerp word nie, gaan dit voort met koolstofbinding van 3-fosfogliseraat (C3) en het ‘n laer koolstofakkumulasie. Dit is ‘n merkwaardige bevinding aangesien KO daarvoor bekend is dat dit ‘n reënvalgradiënt volg: in hierdie geval is Spekboom ‘n uitsondering op die reël. eCognition het Spekboom swak onderskei, en slegs ‘n ooreenstemming van tussen 64% en 69% met die akkurate hand-geklassifiseerde gehad. Soos verwag, toon vergelykende resultate van driedimensionele oppervlakte dat die werklike oppervlakte byna 10% hoër is as die oorspronklike (en gemete) grondoppervlak van die eiendom. Resultate dui aan dat daar aansienlike koolstofvoorrade vir KU op BLK PNR is. Hierdie studie beveel die mees gebruikte praktyke van KU (herstelproses) vir BLK PNR aan. Oor ‘n hersteltydperk van 30 jaar op BLK PNR kan ongeveer 46 000 ton koolstof opgeneem word. Teen die huidige prys van koolstofkrediete kan dit meer as R3.7 miljoen oor die hersteltydperk van 30 jaar akkumuleer. Die kombinasie van herstelprosesse en bewaringstrategieë in een tipe projek, hou addisionele voordeel in, omdat dit die KO-potensiaal van alle plantgemeenskappe op die grondeenheid en die ekosisteem-dienste in berekening bring. Bewaring van BLK PNR sal 757 913 ton koolstof lewer. As dit in terme van die staking van uitlatings bereken word, kan dit teen R8-10 miljoen gewaardeer word. Die ekonomiese belangrikheid van die ekosisteem en plantgemeenskap-biodiversiteit op BLK PNR impliseer ‘n totale intrinsieke waarde van meer as R800 000 per jaar. Loodsprojekte elders was suksesvol in die verkryging van koolstofkrediete vir die vermyding van ontbossing deur die klimaat-, gemeenskap- en biodiversiteitsalliansie (KGBA). Vanweë die loodsprojekstatus, is daar egter min literatuur beskikbaar wat die berekening van die monetêre waarde van bewaring staaf. Dit laat ruimte vir verdere navorsing.

The re-introduction of large carnivores into relatively small conservation areas that fall within the historic distribution range of the species is becoming an increasingly common occurrence. The success of such re-introductions depends very much on the quality of the information that is available to guide management decisions, but in many cases, little information is available. The re-introduction of lions and cheetahs to Sanbona created the opportunity to monitor the behaviour of re-introduced predators to a relatively large system that was characterised by a low ungulate stocking density and little standing water. The broad aims were to study the feeding and spatial ecologies of the lions and cheetahs, to collect standard base-line data, and to examine the effects of the low prey density and limited standing water on habitat selection, range size and diet. The diet (data collected from direct observation and faecal analysis) was similar to that reported in previous studies, and lions and cheetahs preferred greater kudu, black wildebeest and springbok. Lions preferred medium to large prey items, and cheetahs preferred medium to small prey items. The hilly and mountainous terrain of much of the reserve meant that only 50% of the total space was available to the predators. Home ranges of most of the predators were focused around the single large body of standing water. This is likely to have been a response to the water, the vegetation, and the prey that was attracted to these. Habitat selection was also influenced by inter and intra-specific interactions at least for a solitary male lion and female cheetahs. Range sizes were larger than on some other reserves and it is suggested that this was a result of the low prey density. These results form the basis for management recommendations including the importance of continuing to monitor the system and opening up additional parts of the reserve to the predators.

This aim of this study was to improve the understanding and functioning of the Table Mountain Group aquifer system and contribute to the sustainable development of this potential source for water supply in the Montagu area.

In this research the conflict between economic and conservation imperatives in the proposed exploration of shale gas in the South Western Karoo Basin was investigated. The primary aim of this study was to come to a theoretical understanding of the situation through a critical analysis of existing documents which allowed me to outline in detail the two opposing perspectives that either promote or resist a shale gas exploration project. The second objective of this research was to present empirical data from both a questionnaire completed by 20 respondents and two interviews, that helps amplify and verify arguments for or against a shale gas exploration project. The theoretical and empirical components of the research offer the basis for a balanced assessment of the viability of shell gas exploration in the Karoo. Using three fundamental assessment criteria (social, economic and environmental) for what constitutes a sustainable development project the gathered data was analysed in order to help ascertain whether or not the shale gas exploration project is a worthwhile development project. The question answered was whether a shale gas exploration project meets its social, economic and environmental mandates. From this, the final objective of this research was to make recommendations concerning what a responsible policy would be concerning land use in the Karoo.

Thesis (DPhil (Geography and Environmental Studies))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: The rapid growth of tourism, particularly heritage tourism, in South Africa is leading to a detrimental impact on heritage resources. Part of the problem lies in the lack of knowledge visitors have of the significance and vulnerability of the resources they are engaging with. Another part of the problem is the inherent conflict between the heritage tourism sector and the heritage management sector. Whilst sharing the same resource base, each sector has very different aims. Tourism seeks to exploit heritage resources, whilst heritage management seeks to conserve them. These problems are not necessarily restricted to South Africa and the study of its nature and extent is here limited to the Little Karoo. The Little Karoo is defined in this dissertation as the area in the Western Cape bounded by the Langeberg and Outeniqua Mountains in the south, and the Swartberg in the north. It includes the towns of Montagu, Barrydale, Ladismith, Amalienstein, Zoar, Calitzdorp, Van Wyksdorp, Oudtshoorn, Dysselsdorp, De Rust and Herold. Of importance to this research is the fact that the Little Karoo can be accessed by a variety of passes, poorts and kloofs. This study has been undertaken in order to explore a non-empirical solution to the problem of the human impact on heritage resources through their thematic interpretation and presentation. This research also aims to improve the relationship between the tourism and heritage industries by introducing a shared terminology in the form of a model or framework. This framework is a way of organising and presenting the heritage story in such a way that both heritage tourism and heritage managers (and other stakeholders) can understand. The aim of the study is to devise a mechanism with which to identify, organise, interpret and present heritage resources in a thematic manner. The resulting thematic framework will hopefully enrich the heritage experience of visitors to heritage sites while providing guidance as to the vulnerability of heritage resources. A secondary objective is to develop common terminology for the heritage tourism and heritage management communities. The intent is to improve the relationship between these two sectors and thereby mitigate further damage to heritage resources. Data for this study was collected from several empirical sources. Extant and primary data was accessed. Extant data came from the pertinent published sources, while primary data was collected via a combination of personal and group face-to-face semi-structured interviews and personal observation of heritage sites in the Little Karoo during 2003 and 2004. The main outcome of this research was the development of a South African Heritage Tourism Thematic Framework (SAHTTF). The SAHTTF is, in part, based on and inspired by frameworks from the United States, Australia, Canada and South Africa. There are three tiers within the framework: theme groups, themes and sub-themes. The framework is intended to be flexible and the three tiers can be mixed and matched in whatever way best serves the story of the heritage resource in question. The five theme groups are: Development of the environment; Peopling our land; Way of life; Governing South Africa and Developing South Africa. The whole story of South Africa can be organised and presented using this framework. However, in order to keep this study within reasonable limits, the focus of the story was limited to the heritage story of the Little Karoo. The case studies of the Cango Caves, Cogmans Kloof, Swartberg Pass and Seweweeks Poort tested the effectiveness of the SAHTTF. It is recommended that the SAHTTF be presented to the heritage tourism and heritage management sectors for further evaluation and testing. This research has proved that the SAHTTF can be an effective tool in the identification, organization, interpretation and presentation of heritage resources.
AFRIKAANSE OPSOMMING: Die snelle groei van toerisme, veral erfnistoerisme, in Suid-Afrika het tot gevolg dat erfnisbronne onder groot druk geplaas word. Die probleem is deels dat besoekers geen of weinig kennis dra van die kwesbaarheid en belangrikheid van die bronne waarmee hulle handel. Verder is die probleem die belangebotsing tussen erfnistoerisme en erfnisbestuur sektore. Toerisme verbruik erfnisbronne, terwyl erfnisbestuur poog om dit te bewaar. Hierdie probleem is egter nie noodwendig eie aan Suid-Afrika nie en vir die doeleindes van dié studie word die omvang en aard daarvan slegs in die Klein Karoo ondersoek. Die Klein Karoo word beskou as die gebied in die Westelike Provinsie wat in die suide deur die Langeberge en Outenikwaberge en in die noorde deur die Swartberge begrens word. Dit omsluit die dorpe Montagu, Barrydale, Ladismith, Amalienstein, Zoar, Calitzdorp, Vanwyksdorp, Oudtshoorn, Dysselsdorp, De Rust en Herold. Die Klein Karoo kan deur talle passe, poorte en klowe bereik word – die belangrike feit wat in hierdie studie ontgin word. Die navorsing is onderneem ten einde 'n nie-empiriese oplossing vir die impak van die mens op erfnisbronne deur tematiese interpretasie en voorstelling te vind. Dit beoog om die verhouding tussen die bedryf van erfnistoerisme en erfnisbestuur te bestendig deur gedeelde terminologie in die vorm van 'n model of raamwerk. Hierdie raamwerk bied 'n metode om die verhale van erfnis so aan te bied dat beide die bedrywers van erfnistoerisme en -bestuur begrip daarvoor kan ontwikkel. Die doel van die navorsing is om 'n meganisme te vind waardeur die erfnisbronne op 'n tematiese wyse geïdentifiseer, georganiseer, vertolk en aangebied kan word. Hierdie tematiese raamwerk sal hopelik besoekers se ervaring van erfnisbronne verryk en leiding gee rakende die kwesbaarheid van terreine. Data vir die navorsing is uit verskeie empiriese bronne versamel. Bestaande en primêre data is gebruik. Bestaande data was afkomstig van toepaslike publikasies en primêre data is versamel en ingewin via 'n kombinasie van individuele en groepsonderhoude deur middel van semigestruktureerde onderhoude, asook persoonlike waarneming van verskillende erfnisterrreine in die Klein Karoo tussen 2003 en 2004. Die belangrikste opbrengs uit die navorsing is die ontwikkeling van 'n Suid-Afrikanse Erfnistoerisme Tematiese Raamwerk (South Afican Heritage Tourism Thematic Framework – SAHTTF). Die SAHTTF is deels gebaseer op, en geïnspireer deur, soortgelyke raamwerke in die VSA, Australië, Kanada en Suid-Afrika. Daar is drie vlakke in die raamwerk: tematiese groepe, temas en sub-temas. Die raamwerk is aanpasbaar en die drie vlakke kan in enige kombinasie gebruik word om die verhaal of geskiedenis van die betrokke bron ten beste voor te stel. Die vyf tematiese groepe is: Onwikkeling van die omgewing; Bevolking van ons land; Lewenswyses; Regering van Suid-Afrika; en Ontwikkeling van Suid-Afrika. Die hele erfnisverhaal van Suid-Afrika kan georganiseer en voorgestel word deur dié raamwerk. Ten einde hierdie navorsing hanteerbaar te hou, is op die erfnisverhaal van die Klein Karoo gekonsentreer. As gevallestudies het die Kangogrotte, Kogmanskloof, Swartbergpas en Seweweekspoort as toets vir die doeltreffendheid van die raamwerk gedien. Die navorsing beveel aan dat die SAHTTF aan die beheerstrukture van erfnistoerisme en erfnisbestuur voorgelê word vir verdere evaluering en toetsing. Die navorsing het bevind dat die SAHTTF 'n doeltreffende instrument kan wees in die identifisering, organisering, vertolking en voorstelling van ons erfnis bronne.

Thesis (MSc)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Basin subsidence analysis, employing the backstripping method, indicates that fundamentally two different basin-generating mechanisms controlled Tanqua depocentre development in SW Karoo Basin. The subsidence curves display initial dominantly decelerating subsidence, suggesting an extensional and thermal control possibly in a strikeslip setting during the depocentre formation; on the other hand, subsequent accelerating subsidence with time suggests that the dominant control on the depocentre formation in SW Karoo was flexure of the lithosphere. Based on these observations on the subsidence curves, it is possible to infer that the first stage of positive inflexion (~ 290 Ma) is therefore recognised as the first stage of Tanqua depocentre formation. Petrographic study show that most of the studied sandstones of the Tanqua depocentre at depth of ~ 7.5 Km were subjected to high pressure due to the overlying sediments. They are tightly-packed as a result of grains adjustment made under such pressure which led also to the development of sutured contacts. It is clear the high compaction i.e. grain deformation and pressure solution occurred on the sediments; leading to total intergranular porosity reduction of the quartz-rich sediments and dissolution of the mineral grains at intergranular contacts under non-hydrostatic stress and subsequent re-precipitation in pore spaces. Furthermore, siliciclastic cover in the Tanqua depocentre expanded from minimal values in the early Triassic (Early to Late Anisian) and to a maximum in the middle Permian (Wordian -Roadian); thereby accompanying a global falling trend in eustatic sea-level and favoured by a compressional phase involving a regional shortening due to orogenic thrusting and positive inflexions (denoting foreland basin formation). The estimate of sediment volume obtained in this study for the Permian Period to a maximum in the middle Permian is therefore consistent with published eustatic sea-level and stress regime data. In addition, this new data are consistent with a diachronous cessation of marine incursion and closure of Tanqua depocentre, related to a compressional stress regime in Gondwana interior during the late Palaeozoic.
AFRIKAANSE OPSOMMING: Die ontleding van komversakking met behulp van die terugstropingsmetode bring aan die lig dat die ontwikkeling van die Tankwa-afsettingsentrum in die Suidwes-Karoo-kom hoofsaaklik deur twee verskillende komvormende meganismes bepaal is. Die versakkingskurwes toon aanvanklike, hoofsaaklik verlangsaamde versakking, wat daarop dui dat ekstensie- en termiese beheer gedurende die vorming van die afsettingsentrum plaasgevind het, waarskynlik in strekkingwaartse opset. Aan die ander kant toon daaropvolgende versnellende versakking wat mettertyd plaasgevind het dat die vorming van die afsettingsentrum in die Suidwes-Karoo eerder oorwegend deur kromming van die litosfeer beheer is. Op grond van hierdie waarnemings met betrekking tot die versakkingskurwes, kan mens aflei dat die eerste stadium van positiewe infleksie (~ 290 Ma) dus as die eerste stadium van die vorming van die Tankwa-afsettingsentrum beskou kan word. Petrografiese studie toon dat die meeste van die sandsteen wat van die Tankwaafsettingsentrum bestudeer is, op diepte van ~ 7,5 Km aan hoë druk onderwerp was weens die oorliggende sedimente. Die sandsteen is dig opmekaar as gevolg van die korrelaanpassing wat onder sulke hoë druk plaasvind, wat op sy beurt ook tot die ontwikkeling van kartelnaatkontakte aanleiding gegee het. Dit is duidelik dat die sediment aan hoë verdigting, dit wil sê korrelvervorming en drukoplossing, onderwerp was, wat gelei het tot algehele afname in interkorrelporeusheid by die kwartsryke sedimente; die ontbinding van die mineraalkorrels in interkorrelkontaksones onder niehidrostatiese spanning, en daaropvolgende herpresipitasie in poreuse ruimtes. Voorts het silisiklastiese dekking in die Tankwa-afsettingsentrum toegeneem van minimale waardes in die vroeë Triassiese tydperk (vroeë tot laat Anisiaanse tydperk) tot hoogtepunt in die mid-Permiaanse tydperk (Wordiaans–Roadiaans). Dié ontwikkeling het gepaardgegaan met algemene dalingstendens in die eustatiese seevlak, en is verder aangehelp deur saamdrukkingsfase wat gekenmerk is deur regionale verkorting weens orogeniese druk en positiewe infleksies (wat met voorlandkomvorming saamhang). Die geraamde sedimentvolume wat in hierdie studie vir die Permiaanse tydperk bepaal is, met die hoogtepunt in die middel van dié tydperk, is dus in pas met gepubliseerde data oor die eustatiese seevlak en spanningstoestand. Daarbenewens strook hierdie nuwe data met diachroniese staking van mariene instroming en die afsluiting van die Tankwaafsettingsentrum wat met spanningstoestand in die Gondwana-binneland gedurende die laat Paleosoïkum verband hou.

>Magister Scientiae - MSc
The Karoo in South Africa is an area in which petroleum studies are being reviewed with particular interest, especially within the Tanqua and Laingsburg subbasins of the Karoo. The particular formations of interest comprises of the Laingsburg, Fort Brown, Kookfontein and Vischkuil of the Upper Ecca group, located within the Laingsburg subbasin as well as the Kookfontein formation found within the Tanqua subbasin. The present work dealt with interpreting and distinguishing the different types of source rock lithologies, to identify the source rock zones and organic matter within the Laingsburg, Fort Brown, Kookfontein and Vischkuil formations. This was achieved by utilising different geochemical analyses (such as rock eval pyrolysis and TOC) and organic chemistry (XRD) to assess the maturity, mineralogy and the quality of the source rocks.

The Tshipise Basin is considered to be a fault bounded remnant of a larger Karoo aged basin that was fragmented and preserved in the outline seen today by a number of ENE-WSW and NW-SE trending basement faults. It consists of several long, narrow blocks in which the Karoo strata dip, on average, at 12° to the NNW (354). These blocks are bounded to the north by the basement faults that juxtapose the Karoo strata against the high-grade metamorphic rocks of the Limpopo Mobile Belt. The orientation and form of these faults were greatly controlled by the geometry of the metamorphic foliation of the underlying basement rocks. The pre-Karoo topography consisted of a number of ENE-WSW trending palaeo-valleys, with drainage occurring towards the WSW. The southern-most Makhado valley contains a much thicker accumulation of sediments compared to any of the blocks to the north and is considered to have been the main depository of the Tshipise Basin. The sediment ratio maps indicate that the N-S and NW-SE trending faults influenced the deposition of most of the lower Karoo (Tshidzi, Madzaringwa and Fripp formations) and were areas of enhanced subsidence. The coarse-grained sandstone of the Fripp Formation marks the beginning of a major tectonic event that resulted in active uplift in the SE of the basin. The thick accumulation of this unit in the Makhado Block, suggest that the faults bounding the valleys underwent movement during the pre-Fripp tectonic event. Palaeocurrent measurements in the eastern and northern part of the basin as well as the Tuli Basin indicate a unimodal transport direction towards the NW. However measurements in the central and western part of the basin deviate towards the W and SW. The change in palaeocurrent direction, from NW in the east to WSW in the west, is ascribed to the localised changes in basin relief from differential movement of the individual blocks during the pre-Fripp tectonic event. It is either during this Fripp event, or by the time of the Klopperfontein Formation that the ENE-WSW trending faults separated the Tshipise and Tuli basins. The units above the Madzaringwe Formation are all rift-related sediments while the Bosbokpoort Formation possibly contains a series of unconformity bounded sequences which relate to the cannibalization of the underlying strata. Sedimentation within the basin ceased with the onset of the Karoo Igneous Province; which was a product of the splitting of Gondwana into the African and Antarctic continents. Magmatism was initially focused around at the Mwenezi Triple Junction, which firstly led to the outpouring of lava and the intrusion of the Okavango Dyke Swarm (ODS), the Save- Limpopo Dyke Swarm (SLDS) and the Lebombo Monocline. It was during this event that the vast array of dolerite sills were intruded into the Karoo sediments. The ENE-WSW trending SLDS was the first to evolve as a result of stretching and thinning of the crust in a NW-SE direction at ±182-174 Ma (NE-SW directed SHmax). This extension was roughly perpendicular to the underlying basement structures and led to the reactivation of the ENEWSW trending faults which down-faulted and rotated the Karoo strata to the north and preserved them within half-grabens. A second tectonic event, with a SHmax towards the NW/NNW-SE/SSE, led to some degree of inversion of the structures and is likely related to a change in the motion of the African and Antarctic continents after separation. This event probably initiated dextral transpression and compression which led to the reactivation of the primary structures (normal faults) created during the initial event to form relatively high-angled (40-60°) reverse faults across the basin. The event also led to the formation of the subtle east-west trending lowamplitude folds in the Karoo strata, preferentially localised along the ENE faults. Drilling induced fractures and borehole breakout from the ATV logs indicates a neotectonic SHmax parallel to the underlying WSW-ENE trending basement fabric. The large and small scale structures existing in the Limpopo Mobile Belt played a significant role in the development of the Tshipise Karoo Basin. These structures shaped the depository into which the Karoo sequences were laid down, affected the sedimentation and ultimately controlled the fragmentation of this basin along these faults into the preserved blocks seen today.
Dissertation (MSc)--University of Pretoria, 2017.
Geology
MSc
Unrestricted

Includes bibliographical references.
Karoo rangelands exhibit spatial and temporal patterns that have important implications for the livestock industry. Spatially, there are gradients, often abrupt, in ecosystem structure and functioning, while plant composition and productivity are highly variable over time. A predictive understanding of these patterns, and the processes that cause them, is a prerequisite for developing appropriate restoration strategies. This thesis comprises several studies that attempt to relate vegetation patterns and processes to restoration strategies in southern Africa's Succulent- and Nama karoo ecosystems. One hypothesis is that small-scale changes in soil physical and chemical properties are responsible for the fine-scale patterning evident in winter-rainfall Succulent karoo ecosystems. Alternatively, these patterns could be the result of area-selective grazing by livestock. To evaluate these hypotheses, plant and soil data were collected along soil- and grazing gradients radiating from a watering point in a Succulent karoo landscape. Results indicated that properties influencing soil hydrology and nutrient status are important determinants of pattern, and that long-term area-selective grazing can permanently change some of these properties. The hypothesis that the stasis of severely degraded patches in this biosphere is a consequence of poor water infiltration and seed limitation was tested in a restoration experiment. It appeared that natural seed availability is not limiting, but water infiltration has to be improved to initiate the restoration process. Removal of shrub material in long-ungrazed and moribund areas on the outer perimeter of the biosphere, had a positive impact in releasing resources for more seedlings and young growth, but did not alter plant species richness. Stocking rate, composition and management of livestock profoundly influence the dynamics and composition of summer-rainfall Nama karoo vegetation. Proponents of non-selective grazing (NSG) argue that the periodic concentration in high densities of livestock in small areas, followed by long resting periods, improves vegetation composition as a consequence of low grazing selectivity, and enhances vegetation productivity and soil ecosystem processes as a result of intense hoof-action, dunging and urination impacts. Despite its application in farming systems, no studies have yet tested the predictions of NSG. I evaluated the effects of NSG on the soils and vegetation of Nama karoo rangeland in a fully replicated experiment. NSG did not alter the fertile-patch matrix, but improved soil infiltration. Plant compositional and cover changes could not be related to NSG. Rainfall was a much stronger driving force. I also explored the economics of NSG at the farm scale under different rainfall and stocking scenarios. An ecological-economic model predicted that NSG would be a viable option in higher rainfall (>200mm) areas because of the forage buffering capacity which enables the manager to maintain livestock through unpredictable droughts. Restoration strategies for the Succulent Karoo have to focus on the resource-retention capacity of the soils. Livestock can reduce this capacity; low-stocking, flexible farming systems are therefore recommended for these more fragile ecosystems. Livestock in the more resilient Nama Karoo can be managed in a NSG system that can lead to an improvement in ecosystem functioning and maintain productivity in times of drought.

Shale gas exploration by means of Hydraulic Fracturing (fracking) has been on the South African (SA) energy agenda since 2010 as a potential alternative energy source to coalmining. Internationally, the desirability of fracking is debated due to increasing evidence of the environmental and health risks fracking poses. However, experts favouring fracking propose this technology as a greener alternative to conventional energy sources such as coal. Limited scientific evidence is available internationally related to knowledge and risk perceptions of fracking and evidence is limited to studies conducted in the United States (US). South African risk perception studies relates to mining, farming, travelling in SA as a foreigner and sexual behaviour. The president of SA called fracking a 'Game-Changer' using industry jargon in the 2014 presidential address. However, SA has failed to produce exploration regulations to date despite oil and gas companies pushing their agendas. Public participation in the process thus far has been limited. This cross sectional study explored the knowledge, health risk perceptions and information sources related to fracking amongst 102 Central Karoo residents through a household survey. Beaufort West municipality was selected as the study site as this is one of the closestareas to Cape Town demarcated for fracking exploration. This study found that 40% of Central Karoo residents do not know what fracking is or the potential risks and benefits thereof. Media is the main information source of 59% of participants. Only half of participants trust their information sources. Those with more trust in their information sources perceived fracking as posing a greater risk. In contrast those believing fracking to pose a low risk were more likely to trust the government and oil and gas companies. More than half of participants (53%) believe that fracking poses an extreme health risk and 78% thought fracking will harm their health. Most commonly listed causes why fracking will make Karoo residents sick includes water pollution (47.4%) and air pollution (19.6%). Higher education was found to have an inverse relationship with trust in the national government A limitation of this study was that farms could not be randomly selected, affecting the representativeness of the sample. There is a major lack of knowledge pertaining to fracking among those living in the Central Karoo which has important implications for managing the process of public participation in the approval of shale gas exploration.

This study details results of small mammal surveys at 24 sites in four biomes (Nama- and Succulent Karoo, Albany Thicket, Grassland) as part of the Karoo BioGaps project to augment baseline biodiversity information needed to guide proposed fracking activities in the Shale Gas Development Area (SGDA) (Holness et al. 2016). A strategic Environmental Assessment (SEA), commissioned by the South African Government, evaluated the potential to exploit the supposedly substantial reserves of shale gas using hydraulic fracturing (“fracking”) in the Great Karoo Basin of South Africa. Terrestrial micromammals (<500g) were captured using Sherman livetraps (September 2016 to March 2017). Sampling over 6580 trap-nights produced 339 captures of 271 individuals representing 14 taxa. Trapping success was low 5.14% (mean per site 0.37± 0.61%). Most captures (87%) and individuals (83%) were recorded in the Nama-Karoo (294 captures, 226 individuals, 15 sites), whereas only 5 captures were recorded in Albany Thicket (3 sites). Four xerophilous/generalist species (Micaelamys spp. (Rock rats), Gerbilluscus paeba (Hairyfooted Gerbil), Macroscelides proboscideus (Round-eared Sengi), and Elephantulus spp. were numerically dominant at most sites, and within most biomes/bioregions; while five rare species were only ever recorded once. Mean α diversity (observed species richness Sobs) per site (2.88 ±1.99) and Shannon-Wiener diversity (1.70 overall, 1.04 ±0.33 per site) were low, with only 5.47 effective species (mean = 3.04 ±1.08 per site) and low equitability (0.64 overall). Sobs was highest in Nama-Karoo (13 species), and lowest in the Grassland and Albany Thicket biomes (2-5 species). Species accumulation/rarefaction curves did not reach asymptotes, and Sobs values for most sites/biomes/bioregions were significantly lower than Chao1 predicted species richness, suggesting that sampling effort did not accurately estimate species richness. However, trapping efficiency was generally high (56-100%; mean 86.7%) which compares favourably with that of two recent published studies in South Africa. Multiplicative beta diversity (βMt) across the SGDA was 4.56 indicating high species turnover between sites/biomes/bioregions. Species turnover was high across biome boundaries, notably Albany Thicket-Grassland (15), Nama-Karoo-Albany Thicket (14), and Succulent Karoo-Grassland (12). Biomes and bioregions tended to plot apart in ordination analyses with relatively low (40-60%) Sorenson similarity, indicating that most regional small mammal communities were well-differentiated. Despite data limitations, 66 new distribution records for 21 sites are reported for the SGDA. Total species richness (including historical records) was highest in the Nama-Karoo (19), particularly the Upper Karoo bioregion (19, mean 6.45 ±2.16, 11 sites), followed by the Grassland (16), and Albany Thicket (5) biomes. Total species richness records for most sites/regions fell within the iChao2 CI bounds, thus integrating trapping and historical records provided a relatively robust data set for subsequent spatial diversity analyses. However, even the total species richness dataset is likely to underestimate true diversity owing to not sampling arboreal species or detecting some cryptic species. Generalized linear analyses indicated that small mammal diversity indices were significantly associated with certain environmental/climatic parameters (livestock, drought). Despite the west to east increase in precipitation, highest diversity was concentrated in the arid north-west Nama-Karoo where dwarf shrubs and succulents predominate. This suggests that environmental and niche filtering are significant proximate factors shaping small mammal assemblages. No significant effects of biotic interactions (particularly competition following Diamond's (1975) first two rules) or resource-mediated niche limitations were evident for SGDA species assemblages. However, results for the Nama-Karoo (i.e. for a natural phytogeographical rather than geoeconomically-defined area) were significant suggesting that biotic interactions may also be proximate factors shaping local assemblages. Site assemblages were significantly nested, indicating that species at species-poor sites were subsets of those at richer sites; and thus, that site communities may have been structured by either long-term (ultimate) regional biogeographic processes (e.g. immigration and extinction related to distances between sites) or habitat filtering operating at local scales. Data deficiencies notwithstanding, my results present the most comprehensive landscape-level analysis for small mammals, and the only baseline dataset (based on randomized sampling) for the Greater Karoo and SGDA. While my results must be treated with caution, I am confident that the recommendations I make on species, sites and regions potentially vulnerable will be a useful guide to possible impacts of fracking in the study area.

Dental caries is a huge problem among the previously disadvantaged population. Early childhood caries is a problem with infants. This thesis contained information concerning the parents knowledge about their children's oral health and their own personal details. These children were all in the age group 2-5 years. The study findings suggest that parent and parents-to-be, need to be informed on oral health issues concerning their children. This should not solely be the task of dentists but other health care workers as well.