Thesis (PhD)--Stellenbosch University, 1986. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The Exxaro Namakwa Sands heavy mineral sands mine at Brand-se-Baai, on the west coast of South Africa, is an important source of income, development and job-creation in the region. However, this comes at a great environmental cost, as strip mining causes large scale destruction of ecosystems through the complete removal of vegetation and topsoil. This is particularly problematic in an environment, such as Namaqualand, where the arid and windy climate, as well as saline and nutrient-poor soils, hamper rehabilitation. These environmental constraints create the need to develop a site-specific rehabilitation program. At Namakwa Sands the objective of rehabilitation is to “rehabilitate and re-vegetate disturbed areas and establish a self-sustaining Strandveld vegetation cover in order to control dust generation, control wind and water erosion, as well as restore land capability. In general, vegetation will be rehabilitated to a minimum grazing standard capable of supporting small stock (sheep) grazing.” In order to achieve this Namakwa Sands conducted rehabilitation experiments with topsoil replacement, seeding of indigenous species and translocation of mature plants. Monitoring is an important part of the rehabilitation process as it allows rehabilitation practitioners to evaluate success and to adapt their management strategies and rehabilitation methods, as well as to evaluate and, if necessary, change their rehabilitation objectives. This study forms part of the monitoring process at Namakwa Sands. It assesses the success of sites that were experimentally rehabilitated in 2001 and a site that was rehabilitated in 2008, using current practice, in order to identify possible management requirements on rehabilitated sites as well as improvements on rehabilitation objectives, methods and monitoring. This study also tests the Landscape Function Analysis (LFA) as rehabilitation monitoring tool by correlating LFA indices with traditional measurements of biophysical variables or their surrogates. Results showed that experimental sites were not successful in returning vegetation cover and plant species richness to the required levels, but did achieve the grazing capacity objective. These sites will need adaptive management to achieve the vegetation cover and plant species richness objectives. The recently rehabilitated site achieved the three-year vegetation cover and plant species richness objectives, as well as the grazing capacity objective, within two years after rehabilitation. Namakwa Sands should therefore continue using the current rehabilitation method. However, rehabilitation should be done in multiple stages in future to decrease the mortality of nursery cuttings and to facilitate the return of late successional species to rehabilitated sites. The sustainability of small stock farming on rangeland with the grazing capacity that is identified as the minimum objective is questionable and this merits further investigation. LFA can be a useful tool to monitor nutrient cycling and soil stability at Namakwa Sands, provided that enough replicates are used. However, LFA cannot be used as is to assess water infiltration at Namakwa Sands, due to assumptions in the calculation of this index that do not hold for the Namaqualand environment. Landscape functioning should be monitored annually to complement vegetation surveys. / AFRIKAANSE OPSOMMING: Die Exxaro Namakwa Sands swaarminerale-sandmyn by Brand-se-Baai, aan die weskus van Suid-Afrika, is ‘n belangrike bron van inkomste, ontwikkeling en werkskepping in die streek. Daar is egter negatiewe omgewingsimpakte aan verbonde, aangesien die strookmyntegniek grootskaalse vernietiging van ekosisteme veroorsaak deur die algehele verwydering van die plantegroei en bogrond. Dit is veral problematies in ‘n omgewing, soos Namakwaland, waar die droë en winderige klimaat, asook die souterige en voedingstof-arme grond, rehabilitasie belemmer. Hierdie beperkings wat deur die omgewing veroorsaak word skep die behoefte om ‘n rehabilitasieprogram te ontwikkel wat spesifiek is tot die terrein. Die doel van rehabilitasie by Namakwa Sands is om te rehabiliteer en herplant op versteurde gebiede en om selfonderhoudende Strandveld plantbedekking te vestig om sodoende stofgenerering te beheer, om wind- en watererosie te beheer, en om grondgebruik-vermoë te herstel. In die algemeen sal plantbedekking gerehabiliteer word tot ‘n minimum weidingskapasiteit wat kleinveeweiding (skaapweiding) kan onderhou. Om dit te bereik het Namakwa Sands rehabilitasie-eksperimente uitgevoer met terugplasing van bogrond, saai van inheemse spesies en oorplanting van volwasse inheemse plante. Monitering is ‘n belangrike deel van die rehabilitasieproses, aangesien dit rehabilitasie-praktisyns in staat stel om sukses te evalueer en om bestuurstrategieë en rehabilitasiemetodes aan te pas, sowel as om rehabilitasiedoelwitte te evalueer en, indien nodig, aan te pas. Hierdie studie vorm deel van die moniteringsproses by Namakwa Sands. Dit assesseer die sukses op persele wat eksperimenteel gerehabiliteer is in 2001 en ‘n perseel wat in 2008 gerehabiliteer is, volgens die huidige praktyk, om moontlike bestuursbehoeftes op gerehabiliteerde persele en verbeteringe aan rehabilitasiedoelwitte, -metodes en –monitering te identifiseer. Hierdie studie toets ook die geskiktheid van die Landscape Function Analysis (LFA) as ‘n rehabilitasie-moniteringsinstrument deur LFA-indekse met tradisionele metings van biofisiese veranderlikes of hul surrogate te korreleer. Resultate dui daarop dat eksperimentele persele nie suksesvol was om plantbedekking en plantspesies-rykdom tot die vereiste vlakke te herstel nie, maar wel die weidingskapasiteit-doelwit bereik het. Hierdie persele benodig aanpassingsbestuur om plantbedekking- en plantspesiesrykdom-doelwitte te bereik. Die perseel wat onlangs gerehabiliteer is, het binne twee jaar na rehabilitasie die drie-jaar plantbedekking- en plantspesiesrykdom-doelwitte, sowel as die weidingskapasiteitdoelwit bereik. Daarom moet Namakwa Sands voortgaan om die huidige rehabilitasiemetode te gebruik. Rehabilitasie moet egter in die toekoms in veelvoudige stadiums gedoen word om die mortaliteit van kwekery-steggies te verminder en om die terugkeer van laatsuksessionele spesies na gerehabiliteerde persele te fasiliteer. Die volhoubaarheid van kleinveeboerdery op weiveld met die minimum vereiste weidingskapasiteit word betwyfel en vereis verdere ondersoek. LFA kan ‘n bruikbare instrument wees om siklering van voedingstowwe en grondstabiliteit te monitor by Namakwa Sands indien genoeg repliserings gebruik word. LFA kan egter nie in die huidige vorm gebruik word om waterinfiltrasie by Namakwa Sands te assesseer nie, aangesien daar aannames in die berekening van die indeks is wat nie juis is in die Namakwaland omgewing nie. Landskapfunksionering behoort jaarliks gemoniteer te word om plantopnames aan te vul.

<p>The aim of this research is firstly, to determine the impact of the current practiced tenure system in the Leliefontein Rural Area on the use of the natural resources and secondly, to devise and establish the most appropriate tenure system that will ensure the sustainable natural resource management on the communal and commonage land of the mentioned area. Quantitative questionnaires, review of relevant literature from documentation, research studies and reports were used to gather information and provide contextual insights. A wide spectrum from the Leliefontein Rural area specifically, Namaqualand in general and other semi-arid and communal areas in Southern Africa were covered with the gathering of the secondary data.</p>

<p>The aim of this research is firstly, to determine the impact of the current practiced tenure system in the Leliefontein Rural Area on the use of the natural resources and secondly, to devise and establish the most appropriate tenure system that will ensure the sustainable natural resource management on the communal and commonage land of the mentioned area. Quantitative questionnaires, review of relevant literature from documentation, research studies and reports were used to gather information and provide contextual insights. A wide spectrum from the Leliefontein Rural area specifically, Namaqualand in general and other semi-arid and communal areas in Southern Africa were covered with the gathering of the secondary data.</p>

Magister Scientiae - MSc (Biodiversity and Conservation Biology) / Heavy metal accumulation in arable land as a result of mining activities, pesticides and fertilisers has become a global concern. Steinkopf and Concordia in the Northern Cape are well-known for subsistence farming, but just as well-known for the nearby copper mining industry. Very little research has been done on heavy metal toxicity in these areas, thus it was of importance to assess the wheat cultivars (Triticum aestivum) historically used in the study areas, to ensure the viability of wheat farming. The nine wheat cultivars screened were Flameks, Knoppies, Rooiwol, Rooigys, Yecoro Royo, Charchia, Witwol, Kariega and Losper. A comparative study was done by determining the concentration levels of Cu, Fe, Zn, Mn, K, Mg, Ca, Na, N and P in the roots and shoots of sensitive and tolerant wheat cultivars. It was established that Witwol and Rooigys were the most tolerant to these adverse conditions. Kariega and Rooiwol were most sensitive. Their tolerance was achieved by excluding copper from the roots and limiting the translocation of copper to the shoots. This trend to exclude copper uptake in Witwol and Rooigys, warrants further investigation on a molecular level to explain these adaptive mechanisms. / South Africa

Magister Scientiae (Biodiversity and Conservation Biology) / Heavy grazing of rangelands in the succulent karoo has placed the biodiversity of these areas at risk. In Paulshoek, overgrazing has resulted in the removal of much of the palatable vegetation from low lying areas. The remaining vegetation is dominated by Galenia africana, an unpalatable shrub. Loss of favourable microsites, competition from Galenia africana, as well as loss of seed banks, may be the cause of poor seedling establishment of palatable species. I explored how high grazing pressure has changed this system by comparing with surrounding private farms, which have a history of less concentrated grazing pressure. I found that heavy grazing increased the seed bank of Galenia africana in the soil and reduced that of palatable perennials. Vegetation cover was significantly lower (p<0.0001) under heavy grazing and consisted mainly of Galenia africana and few palatable perennials. The aim of this study was to test techniques that could restore this area to a more productive palatable shrubland. I propose that rehabilitation can be used to gain an understanding of the ecological factors that may be sustaining this altered vegetation state. My methodology involved biophysical interventions to manipulate this system. Grazing pressure was removed from the study area and vegetation changes were monitored under grazed and protected regimes. No change in plant cover was found after two years. However, there was an increase in cover of palatable perennials in relation to overall cover. I physically manipulated the environment by introducing microcatchments and brushpacks to act as traps for water, seed and organic material. These interventions resulted in few changes, however, I found higher soil moisture levels in microcatchments and under brushpacks than open positions. Cover of ephemerals was also significantly higher (p<0.001) in areas that had been brushpacked. In the absence of a seedbank, I tested whether the introduction of seed would result in recruitment. Seed of four palatable perennial species was sown into open, packed and tilled soil. A low number of seeds germinated in the first year and most seedlings died. Further germination occurred after a rainfall event in the second year, but still in very low numbers. Various microhabitats were implemented to assess seedling establishment requirements. Seedlings were transplanted in microcatchments and open positions; in areas cleared of Galenia, under adult Galenia and brush packs and in bare soil. Microhabitats did not facilitate seedling establishment, and few seedlings survived. Survival of seedlings was influenced by the size of seedling at transplantation and site differences. I conclude that the factors underlying vegetation change are complex. Individual physical and biological interventions offered no immediate change in vegetation cover and composition. However, a combination of interventions may over time and under favourable climatic conditions allow the return of a viable palatable shrubland. / South Africa

Magister Scientiae - MSc / Pastoralists in Africa have developed complex mechanisms by which they can alleviate the threat of drought. They practice mobility as one of the strategies to avoid the worst effects of natural stress and disperse grazing pressure. In the past in South Africa, the indigenous Nama people occupied large areas of land and moved around extensively to exploit seasonal differences in the availability of forage and water. With the settlement of the Europeans in the Cape the indigenous people lost most of their land to the colonists. The Nama people were, therefore, restricted to smaller rangelands and their patterns of rangeland use had to adapt to the spatial constraints. Descendants now herd livestock from semi-permanent stockposts that are scattered throughout the commons. Herders use a range of practices to manage their livestock. The aims of this study was to assess the agro-ecological knowledge of livestock keepers; assess the condition of the rangeland during drought; determine the herding strategies of herders during drought. / South Africa

The study investigates the habitat preferences and ecological adaptations of the klipspringer in the Namaqualand and the southern Cape mountains. Klipspringer social organisation was found· to consist of a monogamously mated pair defending a territory which varies in size according to rainfall. The pair bond is very strong and role differentiation occurs, with the male spending more time than the female in anti-predator vigilance. Anatomical and physiological adaptations include a modified digit structure, kidneys with a high concentrating ability, and a unique pelage for insulation. Seasonal variations in activity patterns and feeding preferences are discussed in relation to weather conditions, metabolic requirements and possible plant defensive mechanisms. Klipspringers avoid competition with other small antelope by preferring more rocky terrain, and possible methods of food separation from dassies are suggested. The significance of all these factors in relation to the conservation and management of klipspringer populations is examined. / Dissertation (MSc)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted

Namaqualand is world renowned for its mass displays of annual wildflowers occurring in highly disturbed areas. Leysera gnaphalodes is a short-lived perennial shrub that encroaches into this wildflower display, lessening the aesthetic appeal. For this reason populations of L. gnaphalodes need to be kept as small as possible. This is usually achieved by tilling the area regularly, but a less disruptive method would be preferable. Alternatives to this approach are explored. The effect of many interacting factors needed to be examined over long periods of time so that alternative management strategies could be evaluated. Ecological modelling was used as it is ideally suited to this purpose. A review of modelling and its application in ecology is given, which includes a description of the modelling process and a discussion of different types of models and their applications. It was hypothesised that grazing and low rainfall, in addition to tilling, could control the population size of L. gnaphalodes. Data was used from an eight-year study conducted to determine the effects of tilling, grazing and environmental factors on the seedbank and population size of L. gnaphalodes. A rule-based mechanistic mathematical model based on the logistic growth curve was constructed to describe the population dynamics of this species. The model-fit was evaluated using Pearson’s correlation coefficients and graphs, and it proved to be a good model. Tilling and low rainfall were both found to be effective in reducing populations of L. gnaphalodes but grazing had no reducing effect. Simulations based on the model were run to test three different basic management strategies under stochastic rainfall conditions. The management strategy, which most effectively controlled the population was to till the lands whenever the population of L. gnaphalodes reaches of exceeds a relative frequency of 45%. Multivariate statistical models were constructed to determine the effects of all of these factors on the population of L. gnaphalodes. Tilling was confirmed to be effective in reducing the population, but grazing was found to have no effect. Low rainfall was also effective in controlling the population but has the disadvantages of being out of management control and also affecting the desirable wildflowers. / Dissertation (MSc (Botany))--University of Pretoria, 2005. / Plant Science / unrestricted

Bibliography: pages 150-158. / Gahnite (ZnAl₂O₄) is commonly associated with sulphide mineralization in metamorphosed massive sulphide deposits, and also occurs in marbles, pegmatites and quartz veins. Its formation has been attributed to the breakdown of Zn-staurolite or desulphidation of sphalerite during metamorphism. The stability of zinc-rich spinels under a wide range of metamorphic conditions in a variety of lithologies results in its persistence in rocks where many other prograde, high temperature minerals and sulphides have been altered. Thfs has resulted in various investigations into its use in exploration and potential for determining metamorphic parameters. With the interest in finding new ore bodies and in determining the metamorphic history and mineralogy in Namaqualand, some gahnite-bearing localities have been investigated in this study.