Dissertations / Theses: 'Grasslands – South Africa'

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Judd, Rachel Anne. "The coastal grasslands of the Eastern Cape west of the Kei River." Thesis, Rhodes University, 1999. http://hdl.handle.net/10962/d1003772.

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The grasslands of South Africa are the foundation of commercial and subsistence agriculture yet they are being degraded at an alanning rate. The coastal grasslands of the Eastern Cape are no exception and they suffer added pressure of coastal resort development because of their proximity to an attractive coastline. In order to determine the degree of conservation necessary for any area it is essential to know what species occur there in order to determine if protection from habitat destruction is required. Four aims were defined for this studv. The initial aim was a phytogeographical classification of the grasslands in the coastal region west of the Kei River. This was done by vegetation sampling followed by computer based analysis with TWINSPAN. This analysis defined ten grassland associations. five being located in the area west of the Keiskamma River and five occurring east of it. The associations in the eastern half are termed mesic while those in the western balf are xeric. The second aim was to determine the presence of any underlying ecological gradients affecting the distribution of tbe associations. Indirect gradient analysis was carried out where samples are analysed irrespective of environmental factors. Direct gradient analysis was then carried out using scores per sample of various environmental factors. Environmental factors whicb migbt produce such gradients are both naturally-ocurring and man-induced. Natural factors which were recorded in the field include depth of soil at sample site, soil family, aspect and distance from the shore. An important factor is the land / sea interface. Natural factors analysed in the laboratory include soil pH. conductivity. percent organic matter, calcium, magnesium, phosphate and potassium. Man-induced factors are land use history e.g. Ploughing and grazing. Both direct and indirect gradient analysis were carried out with the computer based programme CANOCO. The third aim of the study was to determine the presence of any successional trends between the ten defined associations. This was done using several characteristics of the associations. Alpha and beta diversity were the first factors compared between associations. The percentage contribution of the Cyperaceae, Fabaceae, Asteraceae and Poaceae to each association was assessed and compared. The presence of various life forms of the species occurring in each association was determined together with the cover abundance of different classes of grass species. These results were then combined and analysed in the light of the results from CANOCO analvsis. They show that the mesic Themeda Iriandra - Anthospermum herhoceum, association which occurs closest to the shore and with the least disturbance is a depauperate form of the mesic climax Themeda triandra association. The mesic Hyparrhenia hirta - Dtheteropogon amplectens association may be a secondary grassland on account of phosphate and potassiun poor soils and land-use. The mesic Hyparrhenia hirta - Themedo triandra association is a slightly degraded form of the climax association due to grazing. The severely disturbed Stenotaphrum secundatum - C'entella coriacea association, which is located close to the shore, is a secondary grassland. Analysis of the xeric associations indicates a clearly defined ordination of associations on the basis of land-use. The Cynodon daclylon - Helictolrichon hirtulum and Sporobolis africanus - Setaria sphacelata associations which occur where ploughed lands have been left to lie fallow are secondary in nature. The Themeda triandra - Ehrharta calycina association is thought to be the closest representati ve of a climax xeric association but the presence of E. calycina indicates that some disturbance has occurred. The vegetation is subject to moderate grazing. The Cynodon dactylon - Ehrharla calycina and Diheleropogon filifolius - Ehrharla calycina associations are subject to varying intensities of trampling and grazing and are degraded forms of the Themeda triandra - Ehrharla calycina association. Because of tbe overriding influence of the land-use gradient separation along gradients of the remaining eight factors was limited. The effect of fire and temporal change in the mesic Themeda triandra and Hyparrhenia hirta - Themeeia trianda associations was assessed via long-term studies at Potter's Pass outside East London. The results show a quick response to burning with a return to 100% cover within six months by both associations. During spring the two associations could not be separated by either TWINSPAN or DECORANA. indicating a temporal shift from the Hyparrhenia hirta - Themeda triandra association to the Themeda triandra association. The fourth and final aim was to identify plants requiring protection from habitat destruction and to make recommendations for further conservation areas and management of the coastal grasslands. Through the collection and identification of as many plants as possible a species checklist was prepared and the status of each was determined through reference to the Red Data Book of threatened and endangered species. Kniphofia rooperi is vulnerable in the Cape and Euphorbia hupleuroides is considered rare in kwazulu-Natal. Ten species are endemic to the Cape and / or South Africa. The richness of the vegetation lies in the presence of species representative of the four major floras which converge in the eastern Cape. i.e. The Cape, NamaKarroo, Tongoland-Pondolaod floras and the Kalahari Highveld Regional Transitional Zone. Suggestions are made for the conservation of the grassland associations at various sites within the study area based on the present area conserved. Less than 2% of the coastline in the study area is conserved and it is felt that the area under conservation should be increased. Management suggestions based on the available literature are given for both farmed and conserved areas. There is a great potential for further studies on grassland dmamics within the areas surveyed. In terms of management, the grasslands require careful examination to determine the most effective season in which to burn if at all. As with most agricultural systems in South Africa. grazing strategies will benefit from further research. Any additional research on the dynamics of these grasslands can only be of benefit to the sustained utilisation of this vital resource.

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Wakeling, Julia. "Limitations of savanna trees in the highveld grasslands of South Africa." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/9019.

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Includes bibliographical references (leaves 85-91).
Many grassland areas throughout the world may support a woody biomass if fire is suppressed. It is puzzling that fire-tolerant savanna trees do not grow in these grasslands. The Highveld grasslands of South Africa are one such grassland. Hypotheses including fire, human intervention, grass competition and various attributes of soil have been proposed to explain the tree-less nature of the Highveld grasslands, but they have mostly been discounted. In this study it was hypothesised that cool temperatures or low nutrient availability would result in slow growth of saplings in grassland areas that would subsequently not be able to escape frequent fires. Alternatively, frost may exclude trees from grasslands. A seedling transplant experiment of savanna tree species of the Acacia genus, into grassland and savanna areas arranged across an altitudinal gradient, was used to compare growth in these varying climates over one growing season, and the influence of frost on seedlings in the following winter. Soils were collected from grassland and savanna regions to establish if nutrients varied between these areas, and seedling growth was measured in a pot experiment including these different soils. To minimise the effect of other variables, seedlings were watered and grass was excluded. Higher altitude grassland areas were cooler, and the grassland soils that were collected were nutrient-poor, relative to the savanna equivalents, with the exception of one nutrient-poor low altitude soil. Growth was well correlated to both temperature and nutrient availability, and in general there was slower growth in grassland climates and grassland soils compared to in savannas. These seedling growth rates were extrapolated to the growth rates of saplings in natural environments and the time it would take saplings to reach a height above flame height was calculated. This showed that although there were significant differences between growth rates in grassland and savanna soils, the magnitude of these differences was not large enough to prevent saplings from growing into adults in grassland soils. Differences in growth due to temperature variations, however, were large enough to suggest that saplings in grassland climates would grow too slowly to ever reach escape height between frequent fires. Frost caused damage to seedlings and decreased seedling survival at the highest elevation sites, but trees were absent well below the altitudinal limit of frost damage. There has been much discussion about the tree-less nature of the Highveld grasslands, but very little experimental work to back it. Neither temperature nor fire alone can explain the lack of trees. This study provides empirical evidence that slow growth due to low temperatures in combination with frequent fire could exclude savanna trees from the grasslands. The effect of grass competition still needs investigation. The incorporation of fire is useful as it is a fundamental part of C4 ecosystems; this, on top of a base of variable growth due to changes in resource availability. The barely recognised savanna tree-line deserves attention, as savannas continue to invade grasslands in a warming world.

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Crous, Casparus Johannes. "The mesofilter concept and biodiversity conservation in Afro-montane grasslands." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79892.

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Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Conservation planners use many traditional biodiversity conservation tools to help alleviate the global biodiversity crisis. However, ongoing biodiversity loss has stimulated the development of new and improved methods for conserving biodiversity. One such new conservation tool is the mesofilter approach. Mesofilters are biotic or abiotic ecosystem elements which are critical to the well-being of many species, and therefore could help to explain spatial heterogeneity in species across a landscape. It is also complementary to more traditionally used concepts such as coarse- and fine-filter conservation concepts. Applying the mesofilter approach in protected area, conservancy, or land-sparing design and management, could optimise biodiversity conservation in a rapidly developing world. For example, the timber industry has been pro-active in its approach to lessen biodiversity loss, by optimising design and management of the plantation matrix through ecological networks. Here, I explore the use of mesofilters within highly threatened remnant Afro-montane grasslands in KwaZulu-Natal, South Africa, to optimise biodiversity conservation planning for such landscapes. As per anecdotal evidence, I used rockiness in the landscape as a possible driver of species richness and species assemblage variability at the meso-scale, using a multi-taxon and multi-trophic approach. In this montane landscape, I also examined the effect of elevation on spatial heterogeneity of taxa. I further examined the functional responses of taxa to rockiness in the landscape. Rockiness in the landscape significantly influenced the species richness and assemblage structure of three key grassland taxa: flora, butterflies, and grasshoppers. I showed that for plants, this response was due to growth forms such as geophytes and perennial grasses that were more closely associated with rockiness, and therefore the main contributors to observed differences in the dispersion patterns of flora. Grasshoppers were not necessarily responding to higher rock exposure per se, but rather towards the environmental conditions created by rockiness within the landscape, such as lower vegetation density. For butterflies, certain behavioural traits, such as resting, territorial behaviour and/or mate-locating behaviour, were more typical in areas of higher rock exposure. This suggested that rocks are a definite habitat resource to certain butterflies. Overall, this finding where an abiotic surrogate is representative of key taxa in an ecosystem is interesting, as cross-taxon surrogacy has been shown to be stronger than surrogates based on environmental data. Furthermore, taxa responded functionally to rockiness in the landscape. This thesis therefore supports the idea that environmental surrogates are indeed useful for biodiversity conservation planning. Furthermore, ecosystems can potentially have many attributes or features that would be of conservation interest, and delineating a set of mesofilters is a useful way of expressing particular attributes to be used in wildlife conservation evaluation. The concept of the mesofilter as a practical biodiversity conservation tool is therefore validated here. I also argue the importance of habitat heterogeneity for biodiversity conservation planning in this montane grassland landscape. The potential for optimising the design of landscape configurations such as ecological networks, through information obtained from the mesofilter, is emphasised. We can safely add another tool in the biodiversity conservation toolbox of this Afro-montane grassland ecosystem.
AFRIKAANSE OPSOMMING: Bewaringbeplanners gebruik tans baie tradisionele biodiversiteit-bewarings metodes om die huidige biodiversiteits krisis te help verlig. Tog, die huidige voortdurende verliese in biodiversiteit wêreldwyd, vra na nuwer en verbeterde metodes van biodiversiteit-bewaring. Een so ‘n nuwe bewaring metode, is die mesofilter. Mesofilters is biotiese of abiotiese ekosisteem elemente wat kritiek is tot die welstand van spesies, en daarom veral waardevol is om variasie in spesies verspreiding in ‘n landskap te help verduidelik. Daarby is die mesofilter konsep ook komplementêr tot meer tradisioneel gebruike bewaringskonsepte, soos fyn-filter en breë-filter konsepte. Deur die mesofilter benadering toe te pas in die ontwerp en bestuur van beskermde areas, bewaareas, of land-spaar initiatiewe, kan ons biodiversiteitbewaring in ‘n vining ontwikkelende wêreld optimaliseer. Byvoorbeeld, die bosbou industrie is pro-aktief in hul benadering om biodiversiteit verliese te verminder, deur optimalisering van die ontwerp en bestuur van ekologiese netwerke in die plantasiematriks. In hierdie tesis, ondersoek ek die gebruik van mesofilters in hoogs bedreigde oorblyfels Afrikaberg grasvelde in KwaZulu-Natal, Suid-Afrika, om die bewaringsbeplanning van dié gebiede te optimaliseer. Vanaf anekdotiese bewyse, het ek spesifiek gebruik gemaak van klipperigheid in die landskap as ‘n moontlike drywer van spesies-rykheid en spesies-samestelling variasie by ‘n meso-skaal, deur ‘n multi-takson en multi-trofiese benadering. In hierdie berglandskap, het ek ook die effek van hoogte bo seevlak op ruimtelike verspreiding van taksa bestudeer. Verder het ek ook gekyk na die funksionele reaksie van taksa tot klipperigheid in die landskap. Klipperigheid in die landskap het ‘n beduidende invloed gehad op spesies-rykheid en spesiessamestelling van drie sleutel grasveld taksa: plante, skoenlappers, en springkane. Ek wys dat vir plante, hierdie reaksie as gevolg was van spesifieke plantgroeivorme, soos bolplante en meerjarige grasse, se noue verband met klipperigheid, en daarom, dat hierdie groepe die hoof bydraers is tot gesiene variasie in plantspesies verspreiding in die landskap. Vir springkane, was hierdie reaksie nie noodwendig omdat hulle die klippe self gebruik het nie, maar meer as gevolg van die omgewingskondisies geskep deur verhoogde klipperigheid in die landskap, soos laer plantegroei digtheid. Vir skoenlappers, was hierdie reaksie tot klippe as gevolg van sekere gedragskaraktereienskappe, soos rus op klippe, gebied beskerming en/of paarmaat soektog, wat tipies meer gesien was in klipperige omgewings. Dit dui daarop dat klippe ‘n definitiewe habitat hulpbron is vir sekere skoenlappers. Oor die algemeen is hierdie bevinding, waar abiotiese surrogate verteenwoordig is van drie sleutel taksa in ‘n ekosisteem, baie interessant, siende dat tussen-takson surrogate soms gesien word as sterker as surrogate gebaseer op omgewingsdata. Verder, taksa het funksioneel gereageer teenoor die klippe in die landskap. Hierdie tesis ondersteun dus die idee dat omgewingssurrogate wel nuttig is vir biodiversiteit-bewaring beplanning. Ekosisteme mag vele potensiele elemente van bewarings belang bevat, maar om sulke elemente as ‘n stel mesofilters te klassifiseer, is ‘n nuttige manier om spesifieke elemente te gebruik in natuurbewarings evaluasie initiatiewe. Gevolglik word die konsep van die mesofilter as ‘n praktiese biodiversiteit-bewaring gereedskapstuk hier bevestig. Ek beredeneer ook die belangrikheid van habitat heterogeniteit vir biodiversiteit-bewaring van hierdie berggrasveld landskap. Die potensiaal vir optimalisering van ontwerp en bestuur van landskap konfigurasies, soos ekologiese netwerke, word beklemtoon. Ons kan met veiligheid nog ‘n gereedskapstuk plaas in die biodiversiteitbewarings gereedskapkis van hierdie Afrikaberg grasveld ekosisteem.

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Hoare, David Barry. "Patterns and determinants of species richness in mesic temparate grasslands of South Africa." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1275.

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The aim of this study is to gain a predictive understanding of the patterns and determinants of plant biodiversity in temperate, mesic grasslands of South Africa with a primary focus on the geographical area of the Eastern Cape. From a review of the literature on hypotheses explaining diversity (Chapter 2) it was possible to formulate a number of hypotheses that could be tested to explain species richness patterns in Eastern Cape grasslands. This thesis is organised so that each main chapter deals with a specific body of theory concerning the explanation of diversity patterns. A detailed description of the study area is provided (Chapter 3), including environmental variation and a description of major vegetation patterns. A summary is provided of grassland plant community patterns, as determined by phytosociological studies in the study area. A multivariate analysis of environmental variables was undertaken to determine which variables contributed the most towards explaining environmental variation in the study area and to determine whether any variables co-vary, a possible problem for any multivariate analysis in later chapters. Altitude produced one of the strongest gradients in the study area. There were a number of variables that were correlated with altitude, most notably temperature. Rainfall co-varied partially with altitude, but there was also a strong rainfall gradient perpendicular to the altitude gradient. A description of species richness, diversity and evenness patterns at the plot scale within different grassland plant communities of the Eastern Cape is provided in Chapter 4. To determine whether the environment acts differently on different growth forms, the contribution to species richness by different major growth forms is analysed. Furthermore, since the majority of literature attempts to explain diversity in terms of environmental factors, it was necessary to analyse the relationship between species richness and various environmental variables. The results indicate that there is high variation in species richness both within and among grassland communities. Forbs make the most significant contribution to overall species richness per 100 m2, followed by grasses. Variance in richness of all species together is not significantly related to environmental variables in mesic grasslands, but is significantly related to environmental variables in semi-arid grasslands. The result of greatest interest from this chapter is the fact that richness amongst different life-forms in the same place is explained by different environmental factors, indicating that the environmental factors that affect coexistence of species have a different effect on different life-forms. A classification of all the species of the dataset into plant functional types using a multivariate approach based on functional traits was conducted (Chapter 5). The grass species were classified into 16 functional types and the forbs into 14 functional types. The functional type classification provided the opportunity for undertaking analyses to develop an understanding of 8 the contribution by niche differentiation towards promoting species richness (Chapter 6). The results provide evidence of niche differentiation in the grasslands of the study area and also that niche differentiation promotes species richness in the grasslands of the study area. It was found that higher rainfall grasslands are less structured by niche differentiation than semi-arid grasslands. A regional / historical analysis is undertaken (Chapter 7) to investigate the relationship between the regional species pool and local richness, and the relationship between local richness and phytochorological diversity. Regional richness appears to have little effect in promoting local richness in grassland plant communities of the study area except at sites where there is high local richness. This provides an indication that regional richness only promotes local richness in the absence of local limiting factors. Phytochorological diversity promotes local richness, but mostly through diversity amongst species with narrow distribution ranges. Some theories ascertain that seasonal uncertainty may provide opportunities to species that would otherwise be outcompeted and thereby promote local richness. The degree to which seasonal uncertainty and seasonality promote local richness in the Eastern Cape grasslands was therefore investigated (Chapter 8). A weak relationship exists between these variables and local species richness in grassland communities of the study area, indicating that they do not promote niche differentiation to a significant degree in the study area. It is clear that in the grasslands of the Eastern Cape, environmental limiting factors are more important in semi-arid grasslands and species interactions are more important in mesic grasslands for structuring plant communities (Chapter 9, Discussion). Regional processes do not appear to be important in structuring local communities, but the analysis undertaken in this study shows that they may be significant when factors operating at the other two levels are overcome (species interactions and environmental limiting factors.

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Helm, Chantal Vinisia. "Ecological separation of the black and blue wildebeest on Ezemvelo Nature Reserve in the highland grasslands of South Africa." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-10022007-104926.

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Raitt, Gwendolyn R. "Themeda Triandra Renosterveld in the Heidelberg District." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/20939.

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Thesis (MSc)--University of Stellenbosch, 2005.
ENGLISH ABSTRACT: This study investigated the composition of Themeda triandra Renosterveld in part of the Grootvadersbosch Conservancy and the effects of selected environmental and management variables to provide guidelines for promoting the presence of Themeda triandra in the veld. The Zürich-Montpellier phytosociological method was used to determine the composition of the Renosterveld communities. The point quadrat method was used to determine the cover of Themeda triandra at three grass dominated sites and compare cover from one site with past cover measurements at the specific site. Ordination was used to examine the effects of the environmental and management variables on the plant communities. Two community groups, five communities and five subcommunities were identified and described. The Themeda triandra – Stoebe phyllostachys Grassland Community Group consists of two communities of which one has two subcommunities. The Themeda triandra – Elytropappus rhinocerotis Shrubland Community Group consists of three communities of which one has three subcommunities. The vegetation units described in this study have not been described previously in the literature. One community belongs to Silcrete Fynbos while another subcommunity is transitional between Renosterveld and thicket and gallery forest. The rest of the plant communities fit the definition for Renosterveld (the local Renosterveld type is Eastern Rûens Shale Renosterveld). Cover of Themeda triandra did not differ significantly either between sites or between years. The comparison of Themeda triandra cover between years was done at a site that had been burnt between the last two sampling times yet the cover was not significantly different. This indicates that fire and other management practices did not have a negative impact on Themeda triandra at the site. Unconstrained ordination of the dataset in which cover/abundance values were included, grouped the relevés by moisture and disturbance but the presence/absence dataset indicates that the two community groups have a slight transitional overlap. Constrained ordination of both datasets with a) soil variables and b) management variables, both showed a tendency to separate the relevés into community groups, that did not happen with topographic and vegetation variables. Ordination did not separate the community groups into their subdivisions. The soil variables (both nutrients and texture) influence the vegetation structure and the community distribution. Under the existing grazing management regime, fire at three to five year intervals promoted the dominance of Themeda triandra by affecting the structure of the plant communities, the abundance of species other than Themeda triandra, and influencing which plant community is present. The use of fire as a management tool was regulated by the importance of the natural veld pastures to the farmers. The natural veld pastures are not suitable for dairy cattle in milk. Thus dairy farmers are less likely to burn the natural veld (no planned burns only chance fires) than those who farm with mutton or beef (planned burns on a three to five year interval).
AFRIKAANSE OPSOMMING: Die studie het die samestelling van Themeda triandra Renosterveld in ’n deel van die Grootvadersbosch-Bewaria en die uitwerking van geselekteerde omgewings- en bestuursveranderlikes ondersoek om riglyne vir die bevordering van Themeda triandra in die veld daar te stel. Die Zürich-Montpellier fitososiologiese metode is gebruik om die samestelling van die Renosterveldgemeenskappe te bepaal. Die puntkwadraat-metode is gebruik om ’n skatting van die dekking van Themeda triandra by drie gras-gedomineerde persele te bepaal en om ’n vergelyking te maak tussen die huidige en vorige dekking van ’n enkele perseel. Ordinasie is gebruik om die invloed van omgewings- en bestuursveranderlikes op die plantgemeenskappe te bepaal. Twee gemeenskapsgroepe, vyf gemeenskappe en vyf subgemeenskappe is geïdentifiseer en gedefinieer. Die Themeda triandra – Stoebe phyllostachys Grasland-gemeenskapsgroep bestaan uit twee gemeenskappe waarvan een in twee subgemeenskappe onderverdeel is. Die Themeda triandra – Elytropappus rhinocerotis Struik-gemeenskapsgroep bestaan uit drie gemeenskappe waarvan een in drie subgemeenskappe onderverdeel is. Die plantegroei-eenhede wat in die studie beskryf is, is nie voorheen in die literatuur beskryf nie. Een gemeenskap behoort aan Silkreet-fynbos en ’n ander subgemeenskap is ’n oorgangsfase tussen Renosterveld en struikbosveld of woud, terwyl die res van die plantgemeenskappe binne die definisie van Renosterveld val (die plaaslike Renosterveld tipe staan bekend as Oostelike Rûens Skalierenosterveld). Die bedekking van Themeda triandra het nie betekenisvol gevarieer tussen óf die verskillende lokaliteite óf die verskillende jare nie. Die vergelyking van Themeda triandra-bedekking oor tyd is onderneem in ’n gebied wat tussen opnames gebrand is. Die bedekking het nie betekenisvol verskil nie. Dit dui aan dat vuur en ander bestuurspraktyke nie ’n negatiewe invloed op Themeda triandra in hierdie gebied het nie. Onbeperkte ordinasie van die datastel met die vergelyking van bedekking/volopheidwaardes, groepeer die relevés volgens vogtigheid en versteuring, terwyl die datastel ten opsigte van teenwoordigheid/ afwesigheid aandui dat die twee gemeenskapsgroepe ’n effense oorgangs-oorvleueling het. Beperkte ordinasie van beide datastelle met a) grondveranderlikes en b) bestuursveranderlikes, toon albei ’n neiging om die gemeenskapsgroepe te skei, wat nie gebeur het met die topografiese- en plantegroeiveranderlikes nie. Ordinasie het nie die gemeenskapsgroepe onderverdeel in gemeenskappe of subgemeenskappe nie. Die grondveranderlikes (beide voedingstowwe en tekstuur) beïnvloed die struktuur en die verspreiding van die plantegroei. Met die bestaande weidingsbestuur bevorder brande met ’n interval van tussen drie tot vyf jaar die oorheersing van Themeda triandra deur die struktuur van die teenwoordige plantgemeenskap te beïnvloed, deur die getal van die verskillende plantsoorte te beïnvloed en selfs deur die plantgemeenskap se voorkoms te beïnvloed. Die waarde wat die boer aan die natuurlike veld as weiveld heg bepaal die mate waartoe hulle veldbrand gebruik as ’n deel van bestuur. Die natuurlike veld is nie geskik vir melkkoeie wat in die melkproduksiestadium is nie. Die melkboere is dus minder geneig om die natuurlike veld te brand (geen beplande brande nie net kans brande) as die boere wat met vleisbeeste of skape boer (beplande brande elke drie tot vyf jaar).

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Mongwe, Hlamalani Godfrey. "The status of soil organic carbon under indigenous forests, grasslands, wetlands and pine plantations in Woodbush, Limpopo Province, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16392.

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Thesis (MScAgric)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: Storing soil organic carbon (SOC) is a possible way of reducing atmospheric CO2 and potentially mitigating the effects of global warming. This study looks at soil carbon stocks, the sampling methodology and modelling of soil organic carbon in indigenous forests, wetlands, grasslands and pine plantations in Woodbush in the North-Eastern escarpment of Limpopo Province, South Africa. Dominant Pine species planted in Woodbush are Pinus patula, Pinus elliotti and Pinus taeda. Woodbush plantation was selected as study area because it provided easy access to all the ecosystems that were to be studied. All ecosystems in Woodbush are located in such a way that it was easy to compare them, as they existed under similar environmental and climatic conditions. The climatic conditions of Woodbush promote accumulation of SOC due to relatively higher precipitation and cooler temperatures than most parts of Limpopo Province. Five transects were made: two in indigenous forests and three in plantations. Only the surface (0-7 cm) layer was sampled with a distance of 20 m between sampling points. Transects were not made in grasslands and wetlands because of the patchy occurrence of these ecosystems. In addition to transects, eight 1ha plots, two in each ecosystem, were sampled. Surface (0- 7 cm depth) samples were collected on a grid of 20 x 20 m in each sampling plot. Two soil profile pits were sampled in each sampling plot, with samples being taken at 5, 10, 15, 20 30, 40, 50 60, 75 and 100 cm depth. The average carbon stocks per hectare of land to a soil depth of 100 cm were as follows: 71 t.ha-1 in wetlands, 28 t.ha-1 in grasslands, 64 t.ha-1in indigenous forests, and 46 t.ha-1 in pine plantations. Although wetlands sequestered large amounts of SOC per hectare, their relative contribution to carbon sequestration was low because of the relatively small area (87.2 ha) they occupy in the study area (and in South Africa). Prediction models for vertical distribution of SOC were developed using STATISTICA 6.0 for each ecosystem in order to estimate the carbon stocks to a depth of 100 cm based on SOC content and soil bulk density of the surface samples. These models were developed from observed values in soil profiles for each ecosystem. SOC content and carbon stocks were analyzed using GIS (ARCVIEW). The GIS analysis was aimed at assessing the effect of topography, elevation, soil type, and vegetation on accumulation and distribution of SOC stocks. Most shallow Inanda soils were distributed at elevations between 1545 m and 1777 m, and on a gentle slope in the Northern aspect of the mountain. Deep Inanda soils were found mostly in the lower elevation range of 967 m and 1545 m on moderate slopes. Deep and shallow Inanda soils were found on the southern aspect. Deep Kranskop soils are evenly distributed and mostly found at an elevation range of between 1080 and 1430 m on gentle slopes, while at an elevation range of between 1430 and 1780 m, they were found on moderate slopes. Deep soils had higher SOC stocks than shallow soils and soils in the southern aspects had higher SOC stocks than in the northern aspects.
AFRIKAANSE OPSOMMING: Die berging van grond organiese koolstof is ‘n moontlike manier om atmosferiese koolsuurgas (CO2) te verminder en dus om die invloed van globale verwarming te versag. In hierdie studie was die grond-koolstof voorraad bestudeer, asook die metodologie van die monsterneming en modellering van organiese grond-koolstof van inheemse woude, vleie, grasvelde en denneplantasies. Die studie was uitgevoer op Woodbush plantasie gele op die Noord-Oosterlike platorand van die Limpopo Provinsie, Suid-Afrika. Die algemeenste dennespesies in Woodbush is Pinus patula, Pinus elliotti en Pinus taeda. Die Woodbush plantasie was gekies as studiegebied omdat dit oor al die ekosisteme wat bestudeer moet word, beskik. Die ekosisteme in Woodbush is naby mekaar en dus maklik vergelykbaar want die omgewings- en klimaatstoestande is eenders. Die klimaatstoestande van Woodbush bevorder die akkumulasie van grond organiese koolstof omdat die reënval hoër en die temperature laer is as in die meeste ander dele van die Limpopo Provinsie. Vyf dwarssnitte was gemaak, twee in inheemse woude en drie in plantasies. Monsters was net uit die grondoppervlak laag geneem (7 cm) met 20 m tussen monsterpunte. Dwarssnitte was nie in grasvelde en vleie gemaak nie want hierdie sisteme is te gelokaliseerd. Monsters was ook geneem in agt 1 ha persele, twee in elke ekosisteem. Oppervlakmonsters (tot ‘n diepte van 7 cm) is op ‘n ruitnet van 20 x 20 m uit elke perseel versamel. Monsters was verder ook geneem uit twee profielgate per perseel, op dieptes 5, 10, 15, 20, 30, 40, 50, 60, 75 en 100 cm. Die gemiddelde koolstof voorraad per hektaar, op ‘n gronddiepte van 100 cm, was as volg: 71 t.ha –1 in vleie, 28 t.ha-1 in grasvelde, 64 t.ha-1 in inheemse woude en 46 t.ha-1 in denneplantasies. Alhoewel vleie groot hoeveelhede grond organiese koolstof akkumuleer, is hulle bydrae tot koolstof akkumulasie laag want hulle beslaan ‘n klein oppervlak binne die studiegebied (87.2 ha) asook klein oppervlaktes binne Suid-Afrika. Voorspellingsmodelle vir die vertikale verspreiding van grondkoolstof was met die gebruik van STATISTICA 6.0 ontwikkel ten einde te skat wat die koolstofvoorrraad op ‘n diepte van 100 cm was. Die skattings was gebaseer op organiese grondkoolstofinhoud en die gronddigtheid van oppervlakmonsters. Hierdie modelle was ontwikkel vanaf die waargenome waardes van grondprofiele vir elke ekosisteem. Die organiese koolstofinhoud van die grond en die koolstofvoorraad is ontleed met behulp van GIS (ARCVIEW). Die GIS ontleding was daarop gemik om die effek van topografie, hoogte bo seespiëel, grondtipe en plantegroei, op die akkumulasie en verspreiding van organiese grondkoolstof, te beraam. Die meeste vlak Inanda grondvorms kom voor tussen 1545 m en 1777 m bo seespiëel, asook op effens steil hellings op die Noordelike berghang. Die diep Inanda grondvorms is geleë op laer hoogtes bo seespiëel, gewoonlik tussen 967 en 1545 m, op effens steil hellings. Beide diep en vlak Inanda gronde word gevind op die suidelike berghang. Diep Kranskop gronde is eweredig versprei en word gewoonlik tussen 1080 en 1430 m bo seespiëel, op effens steil hellings, gevind. Dit kom ook voor op matig steil hellings, tussen 1430 en 1780 m bo seespiëel. Daar is meer organiese koolstof in diep grond as in vlak grond en meer in gronde teen die suidelike hang as op die noordelike hang.

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Gwate, Onalenna. "Modelling plant water use of the grassland and thicket biomes in the eastern cape, South Africa: towards an improved understanding of the impact of invasive alien plants on soil chemistry, biomass production and evapotranspiration." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/54800.

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It is imperative to understand the strong coupling between the carbon capture process and water use to sustainably manage rangelands. Woody encroachment is undermining rangelands grass production. Evapotranspiration (ET) highlights the links between ecosystem carbon capture process and water use. It forms the biggest flux of the hydrological cycle after precipitation yet it is not well understood. The Grassland and the Albany Thicket (AT) biomes in the Eastern Cape, South Africa, provide an interesting space to study the dynamics in rangelands biomass production and the associated water use. Therefore, the main purpose of this study was to contribute towards management of rangelands by understanding the dynamics in rangeland grass production and water use. To achieve this aim, the impact of Acacia mearnsii, an invasive alien plant, on soil chemical properties and rangelands grass production was investigated. This was achieved by analysing the biophysical attributes of A. mearnsii as they related to grass production. Secondly, selected soil variables that could be used as a prognosis for landscape recovery or deterioration were evaluated. In addition, aboveground grass biomass was measured in areas cleared of A. mearnsii and regression equations were prepared to help model aboveground grass biomass in areas cleared of A. mearnsi. The thesis also explored dynamics in water vapour and energy fluxes in these two biomes using an eddy covariance system. Consequently, water vapour and energy fluxes were evaluated in order to understand landscape water use and energy partitioning in the landscape. The study also tested the application of Penman-Monteith equation based algorithms for estimating ET with micrometeorological techniques used for validation. Pursuant to this, the Penman- Monteith-Leuning (PML) and Penman-Monteith-Palmer (PMP) equations were applied. In addition, some effort was devoted to improving the estimates of ET from the PMP by incorporating a direct soil evaporation component. Finally, the influence of local changes in catchment characteristics on ET was explored through the application of a variant of the Budyko framework and investigating dynamics in the evaporative index as well as applying tests for trends and shifts on ET and rainfall data to detect changes in mean quaternary catchment rainfall and ET. Results revealed that A. mearnsii affected soil chemical properties and impaired grass production in rangelands. Hence, thinning of canopies provided an optimal solution for enhanced landscape water use to sequestrate carbon, provide shade, grazing, and also wood fuel. It was also shown that across sites, ET was water limited since differences between reference ET and actual ET were large. ET was largely sensitive to vapour pressure deficit and surface conductance than to net radiation, indicating that the canopies were strongly coupled with the boundary layer. Rangeland ET was successfully simulated and evaporation from the soil was the dominant flux, hence there is scope for reducing the so-called ‘unproductive’ water use. Further, it was shown that the PML was better able to simulate ET compared to the PMP model as revealed by different model evaluation metrics such as the root mean square error, absolute mean square error and the root mean square observations standard deviation ratio. The incorporation of a soil evaporation component in the PMP model improved estimates of ET as revealed by the root mean square error. The results also indicated that both the catchment parameter (w) and the evaporative index were important in highlighting the impacts of land cover change on ET. It was also shown that, despite changes in the local environment such as catchment characteristics, global forces also affected ET at a local scale. Overall, the study demonstrated that combining remote sensing and ground based observations was important to better understand rangeland grass production and water use dynamics.

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Zaloumis, Nicholas Paul. "South African grassland ecology and its restoration." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6629.

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The aim of this study is to investigate how human related disturbances affect mesic grasslands. I identified what was lost from the system after a disturbance and what biological constraints ecologists and managers will face when approaching their restoration. I then investigated biological limitations to grassland restoration by attempting species reintroduction into secondary grasslands and exploring the interaction between grasses and forbs.

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Swanepoel, Barbara Anna. "The vegetation ecology of Ezemvelo Nature Reserve, Bronkhorstspruit, South Africa." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-09142007-143511.

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Kamffer, Dewald. "Community-level effects of fragmentation of the afromontane grassland in the escarpment region of Mpumalanga, South Africa." Connect to this title online, 2004. http://upetd.up.ac.za/thesis/available/etd-11242004-104932.

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12

Rampartab, Chanel. "Facilitating golden mole conservation in South African highland grasslands : a predictive modelling approach." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20967.

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Golden moles are subterranean mammals endemic to sub-Saharan Africa and threatened by anthropogenic habitat loss. At present, little is known about the biology, taxonomy, distribution and severity of threats faced by many of these taxa. In an attempt to raise awareness of these elusive grassland flagship taxa, the Endangered Wildlife Trust's Threatened Grassland Species Programme (EWT-TGSP) identified the need for more information on the distributions and conservation status of four poorly-known golden mole taxa (Amblysomus hottentotus longiceps, A. h. meesteri, A. robustus, A. septentrionalis) that are endemic to the Grassland Biome, and which may be heavily impacted by anthropogenic habitat alteration in the Highveld regions of Mpumalanga Province. This study employed species distribution modelling to predict the distributional ranges of these taxa, and involved four main processes: (i) creating initial models trained on sparse museum data records; (ii) ground-truthing field surveys during austral spring/summer to gather additional specimens at additional localities; (iii) genetic analyses (using cytochrome-b) to determine the species identities of the newly-acquired specimens, as these taxa are morphologically indistinguishable; and (iv) refining the models and determining the conservation status of these Highveld golden moles. Initial species distribution models were developed using occurrence records for 38 specimens, based on interpolated data for 19 bioclimatic variables, continuous altitude data, as well as categorical spatial data for landtypes, WWF ecoregions and vegetation types. These initial models helped to effectively focus survey efforts within a vast study area, with surveying during the austral spring-summer of 2013-4 resulting in the acquisition of 25 specimens from across Mpumalanga, nine individuals of which (A. h. meesteri n = 2; A. septentrionalis n = 5; unknown n = 2) were captured in five new quarter-degree-squares (QDSs) where no previous golden moles have been recorded. Additionally, observed activity was also recorded in nine new QDSs (see Appendix 3), showing that the model refinement methods used (variable selection, auto-correlation, non-repeated versus cross-validated models, jackknife of variable importance and localities, independent data testing) were effective in locating golden mole populations. By using genetically-identified historical golden mole records, predictive distribution models were calibrated in maximum entropy (MaxEnt) software to focus ground-truthing efforts.

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Sayuti, Zulhazmi. "Montane South African grasslands as a new planting design form in urban greenspace." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/4557/.

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The aims of this study were to develop communities of South African montane grassland species as a new planting design form in urban parks and green spaces. The uniqueness on the canopy texture and structure additionally the attractiveness produced from colorful flowers, from spring, summer and autumn potentially give strong design impact. To develop the community for use in urban greenspace three series of experiment were conducted to investigate time of sowing, growth performance, winter hardiness, competition in communities and appearance. Most of the species show good emergence and growth performance when sowing seeds directly in the field between March and May. Pre-germination treatments did speed up germination post sowing in the field but do not result in a significant increase of emergence percentage compared sown directly. Studies on species hardiness during extreme cold winter in 2010/2011 on different types and depth of media (sand 70 mm, sand 140 mm and soil 70 mm) found that increase in depth of mulch decrease the survival of the species on sand. Increased seedling mortality was due to lower root zone temperatures in the deeper sand with ambient temperatures as low as -8.7 °C. Most of the species sown in soil shows a better survival than sown in sand. Greater soil wetness in soil was less hostile to overwintering survival than was the lower temperatures associated with the sand treatments. Evergreen species such as Dierama robustum, Berkheya multijuga, and Senecio macrospermus overwintered well and Gladiolus saundersii is one of the hardiest species in this experiment. In the competition experiment, forbs species were the most productive in producing biomass and % cover in every community. Berkheya purpurea is a highly productive species and dominant in the first and second year of this study and greatly affected the production of biomass and canopy coverage in the communities it was present in. The communities with forbs species in combination produced 50% cover faster approximately 50 days after spring cutting in the second year. The geophytes species had much less influence on the biomass and % cover in the community, at least in the first two years. Even though Kniphofia uvaria also able to produce high biomass but does not greatly increases % cover due to the canopy structure being more open. However, the combination of species with different canopy layers is a very effective spatial arrangement for naturalistic design. High germination percentage as well as good growth in the first and second years of study showed that most species are able to survive and flower well in the UK. Most of forbs from low canopy species flower early in the season on the first and second years while geophytes species with slow growth, medium and tall canopy flowering from mid-season until a late season. Based on the results of these studies it appears that South African montane grassland have good potential to be used as a new planting design in UK urban greenspace

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Joubert, Lize. "Biodiversity value of grassland ecological networks in afforested areas, KwaZulu-Natal, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6465.

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Thesis (MSc)--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The current biodiversity crisis requires creative initiatives for mitigating further biodiversity loss. The use of ecological networks (ENs) is such an initiative. The South African forestry industry recognizes that there is loss of biodiversity at the smaller patch scale, while attempting to mitigate this loss at the landscape scale by implementing largescale ENs. The aim of this study was to determine how representative grassland biodiversity in ENs are of similar habitat in a nature reserves (NR). The study was conducted in the northeast of the KwaZulu-Natal Province, adjacent iSimangaliso Wetland Park, which is a natural World Heritage site. A systematic approach compared a wide range of taxa, namely plants, decomposition macrofungi, vertebrates (birds and large mammals) and faunal manifestations (e.g. molehills, dung and ant nests) between the EN and nature reserve, while controlling for differences in disturbance regime. Species richness was compared using Mann-Whitney U tests, while differences in species composition were determined using Correspondence Analyses, Multi-Dimensional Scaling and Analyses of Similarity. Grassland ENs had significantly less plant species. In addition, there were differences in plant and fungi species composition. Differences were probably caused by (1) degree of isolation i.e. proximity to source habitat patches in the surrounding matrix, and (2) habitat quality. Habitat quality was determined by local disturbance regimes (e.g. grazing and fire) and plantation-induced drought for plants, and size and amount of coarse woody debris for fungi. In addition, significant differences in abundances of mole hills (NR>EN) and small mammal burrows (EN>NR) might have had an effect on succession and regeneration of plant communities. There were differences in plant species composition between grassland EN and that at the adjacent nature reserve. However, differences between EN and NR were small when compared to differences between habitat types at the landscape spatial scale. It is concluded that grassland ENs among forestry plantations contribute to biodiversity conservation in the commercially-productive landscape. This approach to land use planning should be explored for other commercial land uses.
AFRIKAANSE OPSOMMING: Die huidige biodiversiteitskrisis vereis kreatiewe strategieë om ‘n verdere verlies in biodiversiteit te bekamp. Ekologiese Netwerke (EN’e) is een voorbeeld van sulke kreatiewe strategieë. Die Suid Afrikaanse bosbou-industrie erken die verlies in biodiversiteit wat kenmerkend in plantasies gevind word. Implementering van grootskaalse EN’e kan egter die verlies aan biodiversiteit, wat in plantasies ondervind word, temper. Die doel van hierdie studie was om vas te stel hoe goed biodiversiteit in grasveld EN’e soortgelyke habitat in ‘n nabygeleë natuurreservaat verteenwoordig. Die studie was uitgevoer in die noordooste van KwaZulu-Natal, langs iSimangaliso Wetland Park wat ‘n wêrelderfenisgebied is. Ons het ‘n stelselmatige benadering gevolg waartydens ‘n wye verskeidenheid taksa, naamlik plante, makro-fungi, vertebrate (groot soogdiere en voëls) en tekens van diere-aktiwiteit (bv. miersneste, dieremis en molshope), in die EN vergelyk is met die van ‘n natuurreservaat terwyl ons vir verskillende versteuringe gekontrolleer het. Spesiesrykheid is vergelyk met Mann-Whitney U toetse terwyl verskille in spesiessamestelling vasgestel is met Correspondence Analyses, Multi-Dimensional Scaling en Analyses of Similarity. Daar was ‘n statisties beduidende verskil in die hoeveelheid spesies tussen grasveld EN’e en die natuurreservaat. Grasveld EN’e het minder plant spesies gehad. Boonop was daar verskille in die samestelling van plant en fungi gemeenskappe. Verskille was waarskynlik veroorsaak deur (1) isolasie of die hoeveelheid nabygeleë habitatbronne in die omliggende omgewing, en (2) habitat kwaliteit. Habitat kwaliteit word bepaal deur versteuringe (bv. brand en beweiding) en die uitdrogingseffek van plantasies vir plante, en die hoeveelheid en grootte van growwe houtagtige puin vir fungi. Daar was ook beduidende verskille in die hoeveelheid molshope (NR>EN) en klein soogdier gate (EN>NR), wat moontlik ‘n effek kon hê op suksessie en herstel van plantgemeenskappe. Daar was verskille in plantspesiessamestelling tussen grasveld EN’e en die van die langsliggende natuurreservaat. Hierdie verskille was egter klein wanneer dit vergelyk word met die verskille tussen verskillende soorte habitatte in die landskap. Daarom kom ons tot die gevolgtrekking dat grasveld EN’e tussen bosbouplantasies bydra tot die bewaring van biodiversiteit in kommersiële landskappe. Hierdie benadering tot grondgebruik behoort verder verken te word vir ander kommersiële bosbou en boerderypraktyke.

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MacFadyen, Duncan Neil. "The dynamics of small mammal populations in Rocky Highveld Grassland, Telperion, South Africa." Thesis, University of Pretoria, 2014. http://hdl.handle.net/2263/79273.

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The present study investigates trap success, species richness, community structure, capture-recapture ratios, sex, population estimates, climatic effects, diversity, age structure, signs of reproduction, and seasonal changes in the body biomass in seven broad vegetation communities in the Bankenveld Grasslands of Telperion in Mpumalanga Province, and Ezemvelo Nature Reserve in Gauteng Province, South Africa. This study focuses on the effect of past management influences on diversity and abundance. The mean trap success recorded for the study is 8.6%. The Rocky Open Shrub community had the highest trap success recorded (37.03%), followed by the Northern Slope Woodland community (20.09%), Sheltered Woodland Community (14.51%), Rocky Highveld Grassland (11.98%), Degraded Grassland (7.25%), Moist Degraded Grassland (4.73%) and the lowest traps success was recorded in the Burkea Eragrostis Clumps community (4.39%). The capture frequency differed between transformed sites (12.9%) and non-transformed sites (87.1%), although the untransformed Rocky Highveld Grassland had the highest species richness, followed by the transformed Degraded Grassland community. The population of small mammals investigated appears to be resident, however certain species were not recorded at certain times of the year, and local movements are expected. Telperion and Ezemvelo Nature Reserve are estimated to have a population estimate of 377 620 small mammals on the properties. Climate appears to have a direct impact on small mammal fauna, influencing food availability, abundance, home range size and breeding. The summer months had the highest species diversity, possibly due to the fact that animals are reproductively active and more readily recorded, while maximum temperature does not appear to impact species richness, possibly due to the fact that the majority of the species recorded are nocturnal in habits. The Rocky Highveld Grassland community had the highest diversity score (H = 1.89), and is considered the most diverse community with ten species recorded. The Moist Degraded Grassland community had the second highest diversity score (H = 1.87) with eight species recorded. Three species were recorded in the Rocky Open Shrub community with the lowest diversity score (H = 0.65). The study site has a diverse and abundant small mammal fauna, indicative of a balanced ecosystem.
Thesis (PhD)--University of Pretoria, 2014.
Zoology and Entomology
PhD
Unrestricted

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Lowman, Guy Russell Pollock. "Deposition of nitrogen to grassland versus forested areas in the vicinity of sabie, Mpumalanga, South Africa." Thesis, University of the Witwatersrand, 2003. http://hdl.handle.net/10539/20112.

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Nitrogen deposition to adjacent grassland and forested areas in the vicinity of Sabie, Mpumalanga, South Africa was studied. Total deposition amounts to the forested area are calculated to be 7l.2 kg N ha-1 yr1 and to the grassland area, 25 kg N ha· 1 yr1. The average deposition amounts are similar to or at least approach nitrogen mineralisation amounts at nearby sites of 50-70 kg N ha-1 yr1. The deposition amounts are made up of 21.4 kg N ha-1 yr1 dry deposition, 7.8 kg N ha-1 yr1 wet deposition and 42 kg N ha-1 yr1 cloud droplet deposition for the forest. For the grassland, the amounts are 7 kg N ha-1 yr1 dry deposition, 7.8 kg N ha-1 yr1 wet deposition and 10.5 kg N ha-1 yr1 cloud droplet. deposition. For both wet and cloud droplet deposition, the amount attributable to nitrate was greater than that attributable to ammonium. For wet deposition, nitrate contributed 4.1 kg N ha-1 yr1 and ammonium contributed 3.7 kg N ha-1 yr1 to both forests and grasslands. For cloud droplet deposition to forests, the amounts were 28 kg N ha-1 yr1 attributable to nitrate and 14 kg N ha-1 yr1 attributable to ammonium. For grasslands the amounts were 7 and 3.5 kg N ha-1 yr1. In both forests and grasslands, the component of dry deposition contributing the most to deposition was ammonia gas, the amounts being 14.2 and 4.3 kg N ha-1 yr1 respectively. Nitric acid contributes 3.7 and 1.9 kg N ha-1 yr1 respectively and is followed by the nitrogen dioxide component that contributes 1.6 and 0.5 kg N ha- I yr1. Ammonium and nitrate particles contribute the least to deposition. For the forests the amounts are 1 and 0.9 kg N ha-1 yr1 and for the grasslands they are 0.2 and 0.1 kg N ha-1 yr1. A strong seasonal variance in deposition amounts is apparent with maximum deposition amounts occurring in Summer and minimum amounts in Winter. Intermediate amounts are deposited in Autumn and Spring, with the latter season having slightly larger deposition amounts. The seasonal variance is strongly linked to the seasonal rainfall and cloud droplet deposition patterns. Biomass burning is indicated as a possible important factor in influencing the chemical composition of rainfall during Spring. Of the deposition amounts obtained in this study, the deposition from cloud droplets is high compared to other studies and is probably overestimated. Further research into this area is needed.

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Krook, Kristine. "The effect of grassland shifts on the avifauna of a South African savanna." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/6113.

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Bibliography: leaves 88-94.
Two distinct grassland types occur within Hluhluwe-iMfolozi Park (HiP); short stoloniferous grazing lawns and tall, tussock-like 'bunch' grasslands. Grazing lawns are maintained by grazing mammals, among which White Rhinoceros Ceratotherium simum is of major importance. By contrast, tall bunch grasslands are promoted by frequent burning. The extent of each grassland type within the park is highly dynamic and can be altered by changes in mammal numbers and/or fire regimes. Such changes may have cascading consequences on other components of the ecosystem if they show specialisation towards one or other grassland state. This study compared avifaunal assemblages of grazing lawns and bunch grasslands to assess how bird species of the park might change with shifts in the grassland mosaic. Distinct bird communities were associated with each grassland type, including several specialists, and bird distribution as linked to vegetation structure, rather than floristics.

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Skowno, Andrew Luke. "Woody plant encroachment in arid and mesic South African savanna-grasslands: same picture, different story?" Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62603.

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Woody plant encroachment in South Africa’s savanna-grasslands has been considered a rangeland management problem since the early 1900s. This phenomenon, which has been observed globally, is particularly important in Africa given the extent of tropical grassy biomes on the continent and their importance for rural livelihoods. In this study, local and regional scale approaches were used to investigate woody cover change in South Africa across the important savanna-grassland rainfall threshold of 650 mm mean annual precipitation (MAP). The aim was to test this threshold using remote sensing and demographic surveys in order to better understand the patterns, mechanisms and drivers of encroachment. Rates of encroachment and population demographics of Vachelia karroo were compared at arid and mesic savanna sites in the Eastern Cape, using time-series analysis of historical aerial photographs in conjunction with field surveys. Changes in the extent of woodland vs. grassland were then quantified at a national scale (1990-2013) by combining optical and synthetic aperture radar remote sensing data. This produced the first map of woodland- grassland shifts for South Africa and provided the basis for a spatially explicit investigation of the key drivers of change. The local studies revealed higher rates of encroachment at mesic sites than at arid sites, with a correlation between drought and rate of encroachment at the arid site. Vachelia karroo seedlings and stunted saplings were more prevalent at mesic sites than at arid sites and the growth form of adult trees differed significantly between sites. The national remote sensing investigation showed that woodland replaced grassland in over 5% of South Africa’s savanna- grasslands between 1990 and 2014, at rates consistent with other global and regional studies. Spatially explicit models showed a pattern of incremental expansion of woodland along a ‘tree front’ and complex relationships between woodland increase and fire, rainfall, terrain ruggedness and temperature. Overall, the local and regional scale findings of this work highlight the importance of the savanna rainfall threshold (~650 mm MAP) and the presence / absence of fire in understanding savanna dynamics and woody cover change in the context of global drivers such as elevated atmospheric CO2.

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Prinsloo, Dominique. "Impacts of African elephant feeding on white rhinoceros foraging opportunities." Thesis, Nelson Mandela University, 2017. http://hdl.handle.net/10948/13768.

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In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.

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Du, Toit Marié Joey. "Grassland ecology along an urban-rural gradient using GIS techniques in Klerksdorp, South Africa / Marié Joey du Toit." Thesis, North-West University, 2009. http://hdl.handle.net/10394/4197.

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Urban areas represent complex assemblages of unique vegetation communities. The multitude of influences on cities adds to this complexity rendering them an intriguing study object from an ecological point of view. Understanding the underlying patterns and processes operating in urban areas becomes increasingly important with large scale urbanization, making urban areas potential conservation sites of the future. The urban-rural gradient approach often used to study these patterns and processes, aims to quantify the existing gradient allowing comparisons of vegetation at different locations, each with diverse human influences. However, accurately quantifying the urban areas became difficult with the realization that gradients are non-linear and complex. Most previous studies cannot be compared with each other due to differences in measures used to quantify the gradient and a lack of a well defined definition for urban areas. Our study in Klerksdorp focused on testing a model developed in Melbourne (Australia) in an attempt to contribute towards creating a standard set of broad measures to quantify the urban-rural gradient. The methods used in Melbourne aims to set a general standard with which to globally compare urbanized areas taking into account the entire extent of the study area allowing multidimensional insights into the unknown gradients. Thereby placing individual studies into an urbanization context. At the heart of it, the main objective is to observe if any global patterns emerge to shed light on urbanization influences and drivers of ecological processes. In our study, SPOT 5 HRV satellite imagery and GIS techniques were used to calculate measures representing demographic and physical variables, as well as landscape metrics. The accuracy of the demographic measures was constrained by the scale of the available census data and subsequently more information is needed. Results showed that density of people, landscape shape index, and the percent urban land cover best quantified the observed gradient. Potential changes in grassland ecology were identified with vegetation surveys studying both the extant and the soil seed bank. Clear differences were observed in the extant vegetation composition of comparable grassland patches at different locations along the gradient, showing that urbanization does influence grassland vegetation composition and survival in the greater Klerksdorp area. The plant species richness of the existing and the soil seed bank showed significant correlations to the specific soil properties of each sample plot. Both demographic and landscape metrics also correlated significantly to some of the species subsets, emphasizing that both are needed to accurately quantify the urban-rural gradient of the greater Klerksdorp area and identifying potential patterns of species distributions. The urban-rural gradient described in the greater Klerksdoip area is not associated with an increase of exotic species towards the urban centre, but with a decrease of indigenous species richness as one nears the urban centre. Patterns and processes emerging from the current study could meaningfully influence planning and implementation actions concerning human development and conservation of a critically endangered vegetation type.
Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2009.

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Ghaui, Mark. "Grass root gaps : an establishment bottleneck limits trees in savannas and excludes them in South Africa's highveld grasslands." Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/25930.

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The Highveld grasslands of South Africa are climatically capable of supporting trees, yet no trees occur. The fact that no fire adapted savanna trees occur in these grasslands confounds the suggestion that fires maintain these ecosystems. This study addresses the question of what prevents savanna trees from surviving. It was hypothesized that grass root competition for space eliminates the availability of suitable 'gaps' for tree establishment under high rainfall conditions. Demographic bottlenecks on Acacia species populations were determined by examining the ratio of juvenile plants to adult carrying capacity. Below-ground root biomass was quantified in 10cm layers to a depth of 40cm at six sites along an elevation and rainfall gradient. The δ¹²C/δ¹³C ratio was determined for roots collected. High rainfall sites were limited at the tree seedling establishment phase. Fine root biomass to 40cm depth increased with rainfall from 613 g/m³ (Standard deviation = 235.1) to about 1326 g/m³ (Standard deviation = 573.1). The surface layer had significantly higher fine root biomass than other layers, with site mean biomass in the surface layer increasing with rainfall (p<0.00001, F₃.₄₂₃= 18.621). Available gaps for tree establishment decreased with increasing rainfall/elevation; no gaps were found at the Highveld grassland site. The findings of this study point to a strong savanna tree demographic bottleneck exerted, at the seedling establishment phase, by below ground grass competition for space. The Highveld grasslands receive to high rainfall for grass roots gaps to occur and permit seedling establishment.

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Breman, Elinor. "Pattern and process in grass-dominated ecosystems : Vegetation dynamics at the grassland-savanna ecotone in South Africa during the holocene." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527281.

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Maliba, Bheki George. "Plant and arthropod diversity of maize agro–ecosystems in the Highveld and Lowveld regions of South Africa / Bheki George Maliba." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7614.

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Surveys of plant and selected insect species was conducted in Highveld and Lowveld agro–ecosystems of four provinces of South Africa, namely North–West, Mpumalanga, KwaZulu–Natal and Limpopo. The objectives of the study were to compare insect and plant diversity between localities (grassland and savanna) and treatments (maize field, semi–transformed and untransformed) to test for a general relationship between plant and insect diversity along a maize field–field margin gradient. Plant and insect diversity patterns were studied along the gradient and quantified in terms of richness and diversity indices. Plant and insect species compositional turnover was also measured along the maize field–field margin gradient. Plant diversity increased with increasing distance from maize fields into the margin. The flora in maize fields and of margins differed, but in contrast, insect species assemblages were similar in maize fields and margins. There was no statistical difference in insect diversity between treatments (maize field, semi–transformed and transformed). A relationship was revealed between plant and insect diversity, as plant diversity enhanced insect diversity.
Thesis (M.Sc. (Environmental Sciences))--North-West University, Potchefstroom Campus, 2011.

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Winter, Susan Jean. "Attitudes and behaviour of landholders towards the conservation of Overberg Coastal Renosterveld, a threatened vegetation type in the Cape Floral Kingdom." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/18711.

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Thesis (MScConsEcol) -- Stellenbosch University, 2003.
ENGLISH ABSTRACT: This thesis describes the findings of a survey to investigate the attitudes and behaviour of private landholders towards the conservation of Overberg Coastal Renosterveld, a highly endangered grassy-shrubland of the Cape Floral Region (CFR) lowlands, now 94% transformed. Personal interviews were conducted with 36 farmers in the Overberg region of the Western Cape, by administering a questionnaire. The following aspects were quantitatively described using the Statistical Package for Social Scientists (SPSS): Renosterveld management and utilisation behaviour, perceived value of Overberg Coastal Renosterveld; landholder knowledge of its conservation importance and willingness to conserve it. Attitudes towards incentives for conservation; conservancies; and the provincial conservation authorities were also investigated. Willingness to conserve was explored further using SPSS cross-tabulation analyses. It was found that farmers who were more willing to conserve were younger, did not necessarily have a better education, and owned larger farms (> 500 ha) with a greater amount of remnant renosterveld (> 300 ha) than farmers less willing to conserve. Attitudes towards Overberg Coastal Renosterveld were largely negative, due to certain associated plants and animals which are problems for farmers, and because it is not economically advantageous to retain it. However, provision of incentives (of which assistance with fencing and land management was most attractive) and increased extension support will provide practical positive inducements for conservation. There is also a need for more landholder education regarding the scarcity of coastal renosterveld to prevent transformation of remaining fragments. The second component of the study aimed to construct a user-friendly index to measure the conservation attitudes of landholders towards conserving Overberg Coastal Renosterveld. An interative item analysis was executed on the data, using Spearman Rank Order correlations and Cronbach's Alpha. Results yielded an index with two dimensions and a Cronbach Alpha co-efficient of 0.67. The dimensions or components of conservation attitude towards renosterveld included: (i) a landholders' perception of the perceived benefit of Overberg Coastal Renosterveld; and (ii) their willingness to conserve it. The mean conservation attitude score was 0.6 (± 0.03), indicating that landholder attitudes were generally sympathetic towards renosterveld conservation. This suggests that while many landholders do not place a high value on Overberg Coastal Renosterveld due to its low agricultural value, their willingness to conserve it is in some cases higher than expected, which possibly explains the above-average mean conservation attitude score. An analysis of variance showed that the following variables were significantly, positively correlated with conservation attitude: (i) area of Overberg Coastal Renosterveld; (ii) landholder environmental group membership status; (iii) presence of ecotourism activities on the property; and (iv) how long the property had been in the owner's family. The intended application of the index is that index scores (amenable for use in a Geographical Information System database) can assist conservation practitioners in deciding where resources should be allocated, on the assumption that high-scoring individuals are more likely to want to take part in conservation initiatives.
AFRIKAANSE OPSOMMING: Hierdie proefskrif beskryf die bevindings van 'n opname waarin die houdings en gedrag van private grondeienaars ten opsigte van Overberg Kustelike Renosterveld ondersoek word. Altesaam 94% van die oorspronklike renosterveld, 'n hoogs bedreigde, grasagtige struikveld in die laaglande van die Kaapse Planteryk (KPR) , is reeds getransformeer en verander. Persoonlike onderhoude is met 36 boere in die Overbergstreek van die Wes-Kaap gevoer en 'n vraelys is aan hulle gestel. Die "Statistical Package for Social Scientists" (SPSS) is gebruik om die volgende aspekte kwantitatief te beskryf: die bestuur en benutting van Overberg Kustelike Renosterveld; die waarde wat toegeskryf word aan hierdie renosterveld; asook grondeienaars se kennis oor die bewaringsbelang van Overberg Kustelike Renosterveld en hul bereidwilligheid om dit te bewaar. Houdings jeens aansporingsmiddele om bewaring te bevorder, bewareas en die provinsiale bewaringsowerhede is ook ondersoek. Private grondeienaars se bereidwilligheid om betrokke te raak by bewaringswerk is verder ondersoek deur gebruik te maak van die SPSS-kruistabelleringsanalise. In vergelyking met boere wat nie bewaring ondersteun nie, is gevind dat die meer bewaringsgesinde boere jonger is, nie noodwendig 'n beter opvoeding het nie, en groter plase (>500 ha) besit waarop meer brokkies oorblywende Overberg Kustelike Renosterveld (>300 ha) gevind word. Grondeienaars se houding jeens Overberg Kustelike Renosterveld was grootliks negatief. Dit is as gevolg van sekere verwante plante en diere wat deur boere as probleme ervaar word, en omdat dit nie ekonomies lewensvatbaar is om renosterveld te behou nie. Die beskikbaarheidstelling van aansporingsmiddele (waarvan hulpverlening met omheinings en grondbestuur die aantreklikste was), en 'n toename in landbou-voorligting is egter praktiese en positiewe dryfvere wat bewaring kan bevorder. Daar is ook 'n behoefte vir meer opvoeding van grondeienaars oor aspekte soos die skaarsheid van Overberg Kustelike Renosterveld, sodat die verdere transformasie van oorblywende fragmente voorkom kan word. Die tweede gedeelte van die studie was daarop gemik om 'n gebruikersvriendelike indeks te ontwikkel waarmee die bewaringsgesindheid van grondeienaars teenoor die bewaring van renosterveld gemeet kan word. Deur gebruik te maak van Spearman se rangorde-korrelasies en Cronbach se Alpha is die data aan 'n herhalende item-analise onderwerp. Die resultate het 'n indeks met twee dimensies en 'n Cronbach Alpha-koëffisiënt van 0.67 gelewer. Die dimensies of komponente van bewaringsgesindheid jeens renosterveld het onder meer ingesluit: i) 'n grondeienaar se opvatting oor die moontlike voordeel van Overberg Kustelike Renosterveld en ii) sy/haar bereidwilligheid om dit bewaar. Die gemiddelde telling vir bewaringsgesindheid was 0.6 (± 0.03), wat in die algemeen 'n simpatieke houding jeens die bewaring van Overberg Kustelike Renosterveld onder grondeienaars aandui. Hiervolgens blyk dit dat alhoewel heelwat grondeienaars weens die lae landbouwaarde van renosterveld nie 'n hoë waarde op hierdie plantegroeitipe plaas nie, hulle bereidwilligheid om dit te bewaar soms verwagtinge oortref. Dit is dalk 'n moontlike verklaring vir die bogemiddelde gemiddelde bewaringsgesindheidtelling. 'n Variansie-analise het 'n noemenswaardige, positiewe korrelasie met bewaringsgesindheid ten opsigte van die volgende veranderlikes getoon: i) area van Overberg Kustelike Renosterveld; ii) die grondeienaar se moontlike lidmaatskap van 'n bewaringsgroep; iii) die teenwoordigheid van ekotoerisme-bedrywighede op die eiendom; en iv) die tydperk wat die eiendom al in besit van die grondeienaar se familie is. Die voorgestelde gebruik van die indeks is toepaslik omdat die indeks-tellings (wat vir gebruik in 'n Geografiese Inligtingstelsel databasis aangepas kan word) bewaringslui kan help met besluite random die toekenning van hulpbronne. Die aanname is dat individuele grondeienaars wie hoë tellings aangeteken het, met alle waarskynlikheid meer geredelik aan bewaringsinisiatiewe sal wil deelneem.

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Van, der Walt Luanita. "Landscape functionality and plant diversity of grassland fragments along an urban-rural gradient in the Tlokwe Municipal area, South Africa / Luanita van der Walt." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9732.

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Urbanisation is an ever-growing global phenomenon which creates altered environments characterised by increased human habitation, exotic species, impermeable surfaces, artificial structures, landscape fragmentation, habitat loss, and modified energy– and resource pathways. The vulnerable Rand Highveld Grassland vegetation unit in the Tlokwe Municipal area, South Africa, has been extensively degraded and transformed by urbanisation and agriculture. Only 1% of this endangered ecosystem is currently being actively conserved. Grassland fragments in urban areas are considered to be less species rich and less functional than their more “natural” counterparts, and are therefore not a priority for conservation. In this study the effects of landscape matrix quality on intra patch variables, namely plant species diversity and functional diversity, and fine-scale biogeochemical landscape function (as determined by Landscape Function Analysis or LFA) of 30 fragments of the Rand Highveld Grassland vegetation unit were explored. Four urbanisation measures (percentage urban land cover, percentage grass land cover, edge density, and density of people), acting as indicators for patterns and processes associated with urban areas, were calculated for matrix areas with a 500m radius surrounding each selected grassland fragment to quantify the position of each grassland remnant along an urban-to-rural gradient. Using the specific urbanisation measures, the grassland fragments were objectively classified into two classes of urbanisation, namely “rural/peri-urban” and “urban”, to allow for statistical comparisons between intra-patch variables for grassland remnants exposed to similar urbanisation pressures. Plant species composition and diversity were determined in the selected grassland fragments and nine functional traits were described for each species. Plant functional diversity was determined by five functional diversity indices, namely functional richness, evenness, divergence, dispersion, and specialisation. Fine-scale biogeochemical landscape function was determined by executing the LFA method. LFA assesses fine-scale landscape patchiness and 11 soil surface indicators to produce three main LFA parameters (stability, infiltration, and nutrient cycling), which indicates how well a system is functioning in terms of resource conservation and soil processes. Possible relationships between fine-scale biogeochemical landscape function and plant species- and functional diversity were also investigated. NMDS ordinations and basic statistics were used to determine trends and effects within the data. The results indicated that urban grassland remnants had lower mean plant species richness, Shannon species diversity (significantly), and Pielou species evenness than rural/peri-urban grassland fragments. Urban grassland fragments also contained significantly higher percentage of exotic species. Correlations were found between the four urbanisation measures and percentage species of the total species richness possessing certain functional attributes. This indicated that increased urbanisation may influence the species composition and the occurrence of certain plant traits in the selected grassland fragments. Urbanisation seems to have no effect on fine-scale landscape heterogeneity of the selected grassland fragments. Rural/peri-urban grassland fragments had higher infiltration capacity, nutrient cycling potential, and total SSA functionality (although not significantly), which may be ascribed to differences in management practices, such as mowing in urban areas and grazing in rural areas. Rand Highveld Grassland fragments in the urban landscape matrix of Potchefstroom city are just as conservable in terms of plant species diversity and functional diversity, as well as on a biophysical function level involving soil processes than rural/peri-urban grassland fragments. High plant species diversity and the presence of certain plant traits did not contribute to high soil surface stability, infiltration capacity, nutrient cycling potential and total soil surface functioning.
MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

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26

Broomhall, Lynne Susan. "Cheetah Acinonyx jubatus ecology in the Kruger National Park : a comparison with other studies across the grassland-woodland gradient in African savannas." Diss., University of Pretoria, 2002. http://hdl.handle.net/2263/29648.

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The objectives of this study were(1) to analyse a data-set on cheetah home range size, habitat utilisation, prey selection and hunting behaviour in the Kruger National Park (KNP), and (2) conduct a comparative study on the above aspects of cheetah ecology across a variety of African savanna ecosystems. Cheetah home range sizes in the KNP for territorial male cheetahs were 173 km2, 438 km2 for a nomadic male cheetah coalition, and 193 km2 and 179 km2 for two female cheetahs. Cheetahs preferred open savanna habitat, although females used areas with thicker bush such as drainage lines) more than males, probably because this is the preferred habitat of their main prey. Analysis showed that while females were closely associated with drainage lines, males were closely associated with roads. A male cheetah coalition preferred scent marking along roads rather than in the bush. Impala occurred most frequently in the cheetahs’ diet, although males took larger prey than females. Cheetahs hunted and killed more frequently in open savanna, even though impala densities were higher in adjacent habitats. Mean chase distance for successful hunts was 18l9 m and unsuccessful hunts was 96 m. Cheetah hunting success was 20.7%, kleptoparasitism was 11.8%, mean kill retention time was 165 min, kill rated averaged 1 kill per 4.61 days, and consumption rate of a three-male cheetah coalition was 1,4 kg meat/cheetah/day. Across African savanna ecosystems, female cheetah home range size was determined by the dispersion patterns and biomass of medium-sized prey. Female home range size was larger in areas with migratory (833 km2) than sedentary prey (105 km2) and increase as prey biomass decreased in areas with sedentary prey only. Conversely, male cheetah territory size was smaller in areas with migratory (37 km2) than sedentary prey (108 km2). Although it was predicted that male cheetah territory size would be determined by female cheetah density, no relationship was found here. Across a range of African savannas, cheetahs showed distinct preferences for open habitats that provided some woody cover. Adults (40%) and juveniles (20%) of medium-sized prey made up the largest proportion in the cheetahs’ diet. There were, however, significant variations in the size and age groups of prey taken by cheetahs in different areas. Areas with the least amount of cover appeared to have the longest mean chase distance, and the greatest percentage hunting success and incidents of kleptoparasitism (%). A population viability analysis, using VORTEX, found that cheetah population viability was greater in a woodland savanna than a grassland savanna, particularly at small population sizes. While the grassland savanna population was most affected by changes in juvenile mortality the woodland savanna population with exceptionally high cub mortality may be a sink for cheetahs while the woodland population with lower cub mortality and predicted high dispersal rates may be a source. Maximum annual litter size and female mortality rates had large impacts on population persistence.
Dissertation (MSc (Zoology))--University of Pretoria, 2006.
Zoology and Entomology
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Little, Ian Tchagra. "Bird reproductive success and faunal habitat selection as tools for understanding the impacts of land-use management on moist highland grassland biodiversity in South Africa." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11407.

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It has been suggested that natural fires in these grasslands would have occurred as infrequently as every four or more years. Currently, the majority of the system is managed by livestock farmers who burn their land annually at the onset of the rainy season (early in the austral summer).

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Landmann, Tobias. "A case study for Skukuza : estimating biophysical poperties of fires using EOS-MODIS satellite data ; a field and remote sensing study to quantify burnt area and fire effects in South African semi-arid savannas /." Aachen : Shaker-Verl, 2004. http://www.loc.gov/catdir/toc/fy0708/2006485603.html.

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Hansen, Simone. "How flower visitation of remnant grassland patches is affected by commercial timber plantations and an invasive alien species (Rubus cuneifolius)." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/98051.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Our planet is in the midst of a biodiversity crisis, with factors such as land transformation, climate change, anthropomorphic disturbance and invasive species acting together to threaten biodiversity. In South Africa, with minimal natural wood resources, commercial forestry is one of the most abundant forms of landscape transformation. However, a third of the land inside many plantations has been set aside for conservation as unplanted remnant grassland patches (RGPs). These areas are subjected to an additional negative impact by invasive alien species, namely Rubus cuneifolius (American bramble), a weed that is particularly problematic in and around forestry plantations in South Africa. The grassland biome of South Africa is extremely diverse and is of vital importance for the ecosystem services it supplies. Despite this, the grassland biome is under threat as this is where much of South Africa’s forestry plantations are located. Driven by anthropomorphic disturbance, pollinators are in decline. Landscape transformation of natural areas for forestry plantations is likely to affect plant-pollinator interactions which will affect ecosystems and biodiversity. However, it is not known to what extent these ecosystems are affected. It is thought that the impact depends on the complexity of the ecosystem in question, and analyses at the network-level provide insights into the robustness of ecosystems in the face of biodiversity loss. Thus, this study evaluates the effect of natural habitat fragmentation and invasion of the alien species, R. cuneifolius, on flower visitation networks of South African grasslands. The study was conducted in the KwaZulu-Natal Midlands within a commercial timber plantation and a neighbouring protected area (PA). Flower-visitor observations were carried out in uninvaded protected areas and RGPs and in protected areas and RGPs invaded by R. cuneifolius. I found that RGPs within commercial forestry plantations successfully decrease the negative effects of land transformation on the grasslands of the KwaZulu-Natal Midlands, and flower visitation network patterns are largely maintained in these habitat fragments. However, within RGPs, invasion by R. cuneifolius affected the composition and the interaction network structure of flower-visitor and plant communities. The fact that there are unplanted areas within commercial forestry plantations is positive for biodiversity conservation in South Africa. Research has indicated that these areas successfully aid in the conservation of biodiversity and ecosystem functioning. Due to the positive influence that RGPs have on conservation in fragmented and transformed landscapes, it is critical that these unplanted areas are retained. However, the effects of bramble invasion are more intense within RGPs than within protected areas, and therefore, it must be a priority to keep these areas undisturbed. R. cuneifolius has been found to have devastating effects on ecosystem function and network structure. It is also a category 1 invasive plant within South Africa, and its removal is required by law. Therefore, the removal of bramble must be a management priority.
AFRIKAANSE OPSOMMING: Ons planeet is in die middel van 'n biodiversiteit krisis, met faktore soos grond transformasie, klimaatsverandering, antropomorfiese versteuring en indringerspesies wat gesamentlik werk om biodiversiteit te bedreig. Suid-Afrika, besit minimale houtbronne. Daarom is kommersiële bosbou een van die mees algemene vorme van landskap transformasie. Tog is 'n derde van die land binne baie plantasies opsy gesit vir bewaring as oorblywende grasveld kolle (OGKs). Hierdie gebiede word ongelukkig blootgestel aan die bykomende negatiewe impak van die uitheemse spesies, Rubus cuneifolius (Amerikaanse steekdoring), wat veral problematies is in en rondom bosbouplantasies. Die grasveldbioom van Suid-Afrika is baie divers en is van kardinale belang vir die ekosisteem dienste wat dit lewer. Ten spyte hiervan, word die grasveldbioom bedreig waar dit op dieselfde areas as die meerderheid van Suid-Afrika se bosbouplantasies geleë is. Antropomorfiese versteuring lui daartoe dat bestuiwergetalle daal. Landskap transformasie vir bosbou plantasies raak dus plant-bestuiwer interaksies, wat ekosisteme en biodiversiteit beïnvloed. Dit is nie bekend tot watter mate hierdie ekosisteme geraak word nie. Daar word vermoed dat die impak af hang van die kompleksiteit van die ekosisteem. Ontledings van ekosisteme op netwerk vlak kan insigte bied oor die robuustheid van hierdie ekosisteme in die aangesig van biodiversiteitverlies. Dus, die studie evalueer die effek van fragmentasie van natuurlike habitatte en inval van die indringer spesie, R. cuneifolius, op blom-besoekings netwerke van Suid-Afrikaanse grasvelde. Hierdie studie is uitgevoer in die KwaZulu-Natal Midlands binne 'n kommersiële hout plantasie en 'n naburige beskermde gebied (BG). Blom-besoeker waarnemings was in BGs en OGKs sonder R. cuneifolius, en in BGs en OGKs met R. cuneifolius uitgevoer. Ek het gevind dat OGKs binne kommersiële bosbouplantasies suksesvol is om die negatiewe uitwerking van land transformasie te verminder, en blom-besoeking netwerk patrone grootliks gehandhaaf word in hierdie habitat fragmente. Egter, binne OGKs, het R. cuneifolius die samestelling en die interaksie netwerk struktuur van blom-besoekers en plant gemeenskappe negatief geraak. Die feit dat OGKs ongeplant gelaat word, is positief vir die bewaring van biodiversiteit in Suid- Afrika. Navorsing dui aan dat hierdie gebiede suksesvol is om te help met die bewaring van biodiversiteit en ekosisteemfunksionering. As gevolg van die positiewe invloed van OGKs op bewaring in gefragmenteerde en omskepte landskappe, is dit krities dat hierdie areas ongeplant bly. Egter, die gevolge van steekdoring inval is meer intens binne OGKs as binne beskermde gebiede, en daarom moet dit 'n prioriteit wees om hierdie gebiede ongestoord te hou. R. cuneifolius se verwoestende uitwerking op ekosisteem funksie en netwerk struktuur was baie duidelik. Dit is ook 'n kategorie 1 indringerplant in Suid-Afrika, en sy verwydering word deur is die wet vereis. Daarom moet die verwydering van steekdoring ‘n bestuursprioriteit wees.

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Landmann, Tobias. "A case study for Skukuza : estimating biophysical properties of fires using EOS-MODIS satellite data : a field and remote sensing study to quantify burnt area and fire effects in South African semi-arid savannas /." Aachen : Shaker, 2004. http://www.loc.gov/catdir/toc/fy0708/2006485603.html.

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Moreroa, Masilo Peter. "The legal implications of grassland as a threatened treasurer : analysis of Haenertsburg Plains in South Africa." Thesis, 2014. http://hdl.handle.net/10386/1285.

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Thesis (LLM. (Philosophy of Environmental Law and Management)) -- University of Limpopo, 2014
Human well-being and progress toward sustainable development are vitally dependent upon improving the management of the Earth’s ecosystems to ensure their conservation and sustainable use. But while demands for ecosystem services such as food and clean water are growing, human actions are at the same time diminishing the capability of many ecosystems to meet these demands. This study explores the legal framework for the protection of grassland in South Africa. In particular, the study looks at the legal protection introduced to protect grassland in Haenertsburg area in South Africa. This study argues that Grassland is vital to the ecosystem, and plays a pivotal role in maintaining and providing life for many plant and animal species. The grassland is also important in our daily lives and is one of the most threatened biomes in South Africa. The study concludes by arguing that more regulatory measures are needed in order to protect the grasslands as threaten species.

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Ellery, William Nolan. "Classification of vegetation of the South African grassland biome." Thesis, 1992. http://hdl.handle.net/10539/22708.

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A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg 1992.
The aim of the study was to develop understanding of the relationships between vegetation types of the grassland biome of South Africa and the environment, with an emphasis on structural and functional characteristics. The grassland biome in South Africa has traditionally been divided into 'pure' grasslands, assumed to be climatically determined, and 'false' grasslands of recent anthropogenic origin. A review of literature from several disciplines including palaeobotany, archaeology, ecology and biogeography indicates that this is not a valid distinction. It is clear that the distribution of the grassland biome as a whole is poorly understood, but the general correlation between the distribution of biomes and climate elsewhere in the world suggests that this warrants more detailed investigation. A water balance approach was used to develop climatic incices that both predict the distribution of grasslands, and are easy to interpret biologically. The indices are the mean. number of days per annum when moisture is available for plant growth, tbe mean temperature on days when moisture is available for plant growth (wet season temperature),. and the mean temperature when moisture is not available for plant growth (dry season temperature). Based on these three.indices the grassland biome in South Africa call be distinguished from neighbouring biomes. The fynbos and succulent karoo biomes have rainfall in winter. The grassland, nama-karoo and savanna biomes have' rainfall in summer. The forest biome experiences rainfall throughout the year. Of the summer rainfall biomes, the quantity of water available in the grassland biome b greater than in the nama-woo, similar to savanna, but less than forest. Grasslands experience cooler dry season temperatures than savannas. The localised distribution of woody plants within the. grassland biome suggests that it is the effect of climate on the fire regime that may be of overriding importance h'l determining the distribution of the biome as a whole. Woody elements are restricted to sites that are either protected from fire, or experience fires of lower intensity than sites that support- grassland, The unifying feature of the grassland biome is its proneness to fire. The presence of a warm, moist season promotes plant production and leads to a high standing crop close to the ground. The prolonged dry season causes vegetation to dry out annually, rendering it flammable. More arid biomes have plants more widely spaced, making it difficult for fire to spread. In more mesic biomes where rainfall is less sea.sonal than in the grasslands or savannas, fuels do not dry out sufficiently to ignite, A number of additional climatic features may promote burning in the grassland biome, It has the highest lightning density of all South Africa's biomes. 'tVarm, dry 'berg' winds desiccate fuels and 1 omote burning in the more mesic grasslands, The 'curing' of the grass sward due to dry season frost and temperature drop is important in establishing early dry season flammability. Savanna trees are fire tolerant, but they appear sensitive to the cold temperatures prevaient in the grassland biome in. the dry season, The relationship between the distribution of functional characters of grassland plants and environmental conditions was investigated. The distincrion between sweetveld, mixed veld and sourveld was recognised as one of the most Important functional features of South Africa's grasslands, The distribution of these vegetation types was examined in detail. Sweetveld occurs In warm, dry areas; sourveld in cool, moist areas. There Is overlap between these tyP.Js that Is dependant on soil nutrient status. Sweetveld that occurs in climatic conditions that would be expected to support mixed veld and sourveld, is on soils derived from basic parent material, including basalt, dolerite, gabbro and norite. Similarly, sourveld that occurs in areas that climatically would be expected to support sweetveld, is on soils derived from acid parent material such as sandstone and quartzite .. Soil nutrients that are most highly correlated to the occurrence of these three veld types are phosphoms availability and an index of nitrogen mineralization potential. 'l'here is an increase in bot; available phosphorus and the index of readily mineralizable nitrogen from sourveld to mixed veld to sweetveld. These features am inc01).10111tedinto a conceptual model that relates the distribution of these grassland types to carbon and nitrogen metabolism, with the role of phosphorus either similar to nitrogen, or else it may act indirectly by affecting the. rate of nitrogen mineralization, Nitrogen mineralization OCcursat lower water availability than carbon assimilation, and its temperature optimum is higher than that of carbon assimilation. Where nitrogen mineralization is favoured ielative to carbon assimilation, sweetveld is likely to (}C(.1\Xr. Where carbon assimilation is. favoured relative to; nitrogen mineralization, sourveld is likely to occur ....Soil texture affects the balance between these two processes in the degree to wm.r;h it protects soil organic matter, and thereforv the size of the nitrogen and ph_QSPllO_rOll.S pools. Changes in the rlj,stribution of South Africa's b~\omesfor a scenario of climate change are predicted using the biome model developed in this study. This illustrates the value of developing predictive models.
MT2017

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Matjie, Mapula Rose. "A vegetation survey and mapping of the woodbush granite grassland in the Limpopo Province, South Africa." Thesis, 2019. http://hdl.handle.net/10386/3176.

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Thesis (M. Sc. (Botany)) -- University of Limpopo, 2019
The Woodbush Granite Grassland (WGG) is the most threatened vegetation type in Limpopo Province of South Africa. However, it has a high conservation value, because few examples of this vegetation type remain in southern Africa. Unfortunately, a large part of it is not formally conserved, making this the vegetation type most urgently in need of conservation. The study aimed at mapping transformation of the WGG, identifying species of conservation importance, and providing a management plan required for maintenance of the WGG. The objectives of the study included compiling a transformation map for the WGG, which also involved describing the remaining patches of the WGG that are in a natural or near-natural state. It also provides information on species of conservation importance, medicinal plants and threats to the WGG. On the four main study sites (Iron Crown Grassland, Haenertsburg Grassland, Ebenezer Dam Nature Reserve Grassland, and Ebenezer Dam Perimeter Grassland), quadratic plots were randomly set with a size of 25 x 25 m, and subplots of 1 x 1 m. Vegetation mapping was done during summer and winter. At each plot data was collected on all plant species occurring within the quadrat. A cover score was assigned to each plant species. A modified Braun-Blanquet data collection sheet was employed to obtain baseline data. For transformation mapping GeoTerra Image (GTI), land cover data were extracted for the WGG, using the modelled boundary as a mask, with 5 categories of transformation defined. Of the surveyed sites, the Ebenezer Dam Nature Reserve Grassland has the highest number of species, while the Haenertsburg Grassland contained the most endemic species of conservation importance. Rare species such as the Aloe zebrina, which does not occur in any formally protected area, and medicinal plants such as Athrixia phylicoides, occur on the WGG. All sites have importance with regard to WGG conservation. Identified threats include the spread of alien invasive plants, uncontrolled collection of medicinal plants, urban development, and poorly timed anthropogenic fire. vi The WGG underwent transformation to other land classes. Grassland clearing for plantations and cultivation were the main causal factors behind the observed WGG losses, with a total of 55.25% transformed. Transformation by afforestation is considered irreversible. It is concluded that the WGG is of conservation importance, and that some of it has been transformed to exotic timber plantations. The grassland is under various threats; therefore it is recommended that: (1) The proposed management plan provided in this study be adopted, (2) further research on the WGG be done on medicinal plants, (3) phytosociological and floristic studies be conducted and, (4) the effects of fire and alien invasive plant species on the grassland be investigated.

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34

Hutchinson, Lydia. "An initial investigation into key soil processes and associated influences on N and S cycles of grassland site near a coal-fired power station, Mpumalanga, South Africa." Thesis, 2013. http://hdl.handle.net/10539/12705.

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35

Kruger, Linda Eloise. "Regeneration of grassland after removal of pine plantations in the north eastern mountain grasslands of the Drakensberg escarpment, Mpumalanga, South Africa." Diss., 2012. http://hdl.handle.net/2263/29600.

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Concern for the severe loss of biodiversity of grassland species is often voiced. Plantation forestry is known to cause extensive and long lasting disturbance of the natural environment in particular in areas such as the mountain grassland of the Drakensberg escarpment. The survey was conducted in the Graskop area on sites within pine plantations along the Treur River bordering the Blyde River Nature Reserve. The results showed that restoration of plant species biodiversity through natural succession, on cleared plantation sites, required periods longer than seven years and that the regeneration of a great many of the indigenous forb species remained uncertain. Two survey areas were selected and within each survey area, sampling sites were selected to represent three categories of vegetation namely, undisturbed grassland and sites where pine trees had been removed three and seven years previously. Samples of plants were collected from each of these sampling sites. Analysis by means of a classification technique determined the species composition of the disturbed sites in relation to that of the intact grassland. Wheel point surveys were also carried out on these sites to provided information on the vegetation cover, as well as the degree of species regeneration on each site. The variation in vegetation composition of the various plots was ana lysed by means of Detrended Correspondence Analysis (DCA) and Two-Way Indicator Species Analysis (TWINSPAN). The results showed three distinct species assemblages which corresponded with the three categories of sampling sites. Also that the indigenous forbs species comprised 68% of all the sampled species most of which had failed to regenerate in either the three or seven year cleared plots. The most successful grass species in establishing and persisting in all sites were, Eragrostis curvula and Loudetia simplex. The fern, Pteridium aquilinum had a high prevalence on the disturbed grassland plots and the threat of its invasion of these habitats is compounded by the physical disturbance which eradication methods cause. Planning for grassland restoration involves cognizance of the complexity of grassland ecology, the influence of a multiplicity of environmental factors and the proximity of donor sites to the disturbed areas. Applying international restoration techniques used in grasslands of different origins to those of South African landscapes could result in disappointing and costly efforts. At best any attempt at managing grassland diversity should be preceded by an holistic investigation into the environmental conditions particular to the specific terrain and thereafter maintaining a conservative approach of allowing natural succession. The threat of invasive exotic species should be integral to conserving the integrity of the remaining intact natural grasslands in South Africa. It is acknowledged that in this study regeneration of grassland species on plantation sites cleared of pine trees three and seven years previously does not include a long time span such as needed for succession to take place but is useful in showing a trend in species re-colonization to resemble the vegetation of intact grassland, as well as highlighting the absence of a great number of indigenous forb species. Copyright
Dissertation (MInstAgrar)--University of Pretoria, 2012.
Geography, Geoinformatics and Meteorology
Unrestricted

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Makaka, Lukhanyo. "Response of ground dwelling spider assemblages (Arachnida, araneae) to Montane grassland management practices." 2012. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000187.

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M. Tech. Environmental Management.
Aims to investigate the impacts of Montane grassland management practices, particularly through grazing intensity and burning frequency, on ground living spider assemblage structure.More specific aims include:to note any relationship between particular spider species to specific forms of habitat management ; to note the loss of particular species at detected thresholds in management practices ; and to model spider assemblage structure based on grassland management.

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37

Shackleton, Charles Michael. "The grassland dynamics of Mkambati game reserve." Thesis, 1989. https://hdl.handle.net/10539/24238.

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A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science.
This work describes the coastal grasslands of Mkambati Game Reserve and their suitability for the present large herbivore complement. The initial description makes use of both field survey and quantitative sampling and multivariate analysis which facilitated the production of soil and vegetation maps at tre scale of 1: 10 000. Suitability of these grasslands for herbivores is assessed in terms of both quantity and quality of food available and the present herbivore impact. Local variation in soil type was considerable. Eight standard soil forms were distinguished as well as severaI others previously undescribed. Most of the soils were dystrophic although nutrient 'hot-spots' were common. This determined floristic composition of the various communities to some extent. Three grassland communities and four subcommunities were recognized which contributed 81, 5% to the total area of the reserve. The remaining area comprised forest. wetlands. exposed rock and accommodation camps. Each grassland community was associated with particular ranges of the measured environmental variables. The standing crop of the three communities was high relative to other areas of Southern Africa. Absolute amounts varied seasonally being highest in summer and lowest in winter Partitioning between the phytomass, necromass and litter components also varied seasonally. Total standing crop increased with increasing interval since the last fire. Litter breakdown rates differed between communities and species. Forage quality was poor being lowest in autumn and winter and declining with age. This was probably a result of the dystrophic soils. Crude protein and phosphorus were limiting for several months of the year. Total forage quantity was in excess of the present herbivore needs although availability declined with age and during the non-growing season. However, the poor quality reduced the amount available such that present herbivore impact was low, at all times being less than 9%.. Removal by herbivores was highest several months after a fire when absolute amounts of various nutrients were at a maxinum per unit area. Thereafter it declined to less than 1% with aging of the sward. The implications of the results for management are discussed and future research needs identified.
AC 2018

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Ghebrehiwot, Habteab Mesghina. "The role of fire and fire-related factors on germination and growth of grassland species." Thesis, 2010. http://hdl.handle.net/10413/10826.

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Fire, natural or of anthropologic origin is a recurrent phenomenon in South African mesic grasslands. The species composition of these grasslands is sensitive to fire frequency and there exists a permanent fire-species relationship syndrome. The shift follows a general trend where, in the absence of fire for longer periods, the native grass species, possibly the most economically important grass species, give space to relatively less desirable and invasive species accompanied by significant decline in basal cover. Though much is known as to how the floristic composition of the grassland changes in response to fire, the underlying mechanisms responsible for changes in plant vigour and species composition are not fully understood. There exists limited information on germination requirements of the local flora and how recruitment of the species is influenced by fire, fire-related factors and the interaction of these factors among themselves is virtually unknown. Since the discovery by DE LANGE and BOUCHER (1990), plant-derived smoke is being widely studied as an important germination cue and the theme has been the subject of intense experimental research and theoretical work. Germination studies conducted on South African Fynbos, Californian Chaparral, and Australian species have illustrated the widespread ability of plant-derived smoke in promoting germination of species from both fire and non-fire prone habitats. Studies have also showed that plant-derived smoke plays a significant role in vegetative growth of many plants including horticultural and agricultural crops, though mechanisms of smoke action in enhancing germination and promoting plant growth are still under active research. This study sought to gain insight into the role of fire and fire-related cues and other related factors on germination and seedling growth of key grass species from fire-prone grassland in South Africa. In this study, various investigations were conducted on different aspects related to smoke-induced seed germination. Furthermore, in depth examinations were conducted on the effects of fire-related factors such as smoke, heat, soil and nutrients on seed germination and seedling growth of representative key mesic grassland species from South Africa. Laboratory-based germination and vigour experiments were conducted using smoke solutions. The aim was to examine if the strong fire-species relationship syndrome we encounter in post-fire mesic grassland in South Africa is related to the effect of plant-derived smoke on germination and seedling growth. In addition, the interaction of plant-derived smoke solutions with temperature was examined by incubating seeds at a range of temperatures. Treating seeds with smoke-water and butenolide, the germination rate (GR) and final germination percentage (FGP) were greater in 3 of the 6 species. Themeda triandra Forssk. and Tristachya leucothrix Trin. ex Nees showed the greatest response, with final germination increased from 43% to 67% and 35% to 63% respectively. These smoke solutions have also significantly enhanced germination in Eragrostis tef (Zucc.) Trotter from 62% to 80%. The degree of responsiveness varied from species to species and across different temperatures. Findings from this study suggested that plant-derived smoke and its interaction with temperature significantly influence the germination and seedling growth of the South African mesic grassland species, which can further impact on the grassland composition. To characterise the role of plant-derived smoke on certain economically important seed traits, the effect of smoke-water and a smoke-isolated butenolide on seed germination and seedling growth of Eragrostis tef (grass species which has moderately good tolerance to east African drought) was investigated at a range of temperatures, light conditions and osmotic potentials. Smoke-water (1:500 v/v) and butenolide (10ˉ⁸ M) treatment of the seeds increased percentage germination, seedling vigour and imbibition from high to low osmotic potential. These results suggested that smoke solutions have characteristics with overriding effects toppling stresses exerted from high temperature and low osmotic potential, thereby widening the temperature and moisture zone over which germination can occur. Furthermore, these findings suggested that the mode of smoke action in promoting seed germination is likely to be linked to the role of smoke in facilitating water uptake by seeds (imbibition). A simple and rapid bioassay was implemented to detect the germination activity of extracts from soils in pre/post-burn status. Soil samples taken from burnt, unburnt and adjacent plots at depths of 0-2, 2-4, 4-6 and 6-8 cm before and after burning mesic grassland in South Africa were analysed for germination activity over an eight-week period. Soil samples were extracted using dichloromethane and bioassayed using Grand Rapids lettuce (Lactuca sativa L.) achenes. The Grand Rapids lettuce seeds exhibited several-fold greater germination percentages when treated with extracts from burnt soil compared to the other plots. The magnitude of such an activity declined through time since burn. The Grand Rapids lettuce seeds also showed significantly greater germination percentage when treated with unburnt soil extracts compared to the control (distilled water) which indicates the existence of other factors controlling germination in unburnt soil. Germination percentage was negatively influenced in the adjacent plots which reflected the inhibitory role of smoke on adjacent plots neighbouring the burn. Findings from this study suggested that the germination activity of a burning plant-material (smoke) indeed diffuses into the soil and its persistence declines with time. Furthermore, the findings implied that fire and smoke may significantly influence the germination of the soil seed bank of mesic grassland in South Africa. The effect of smoke solutions of various concentrations and their interaction with soil macronutrients NPK in influencing seedling growth of three selected grass species namely, Eragrostis curvula, Panicum maximum and Themeda triandra was investigated. These grass species were selected on the basis of the contrasting response they previously showed to smoke treatments. Results showed that the interaction between species, treatment and nutrients for seedling vigour index was highly significant (P < 0.001). In the absence of NPK elements, the smoke solutions generally enhanced seedling growth in Themeda triandra, while suppressing seedling vigour indices of Eragrostis curvula and Panicum maximum. It is ecologically significant that not only smoke but also its interaction with soil macronutrients appears to be important in structuring the post-fire regeneration and colonisation processes. To examine the effect of fire-associated cues of smoke and high temperature on germination and seedling emergence from the mesic grassland soil seed bank in South Africa, and disentangle responsible factors, the effect of heat and smoke-water on seedling emergence and the resultant effect on biomass production was examined in a greenhouse tray experiment over 90 days. Soil seed bank samples obtained from 0-5 cm top soil were treated with smoke-water solution (SW 1:500 v/v), heat (H = 100 °C for 15 min) and heat + smoke-water (H = 100 °C for 15 min + SW = 1:500 v/v) combined. Significantly, the highest number of seedlings emerged from soil seed bank samples treated with heat + smoke-water combined followed by smoke-water alone. Heat + smoke-water treatment of soil seed bank samples also significantly enhanced the rate of seedling emergence and total dry biomass production. Heat treatment by itself was not statistically different from the control in many respects. Generally, these results suggest that both heat and smoke are important germination cues and play a curial role on germination and seedling emergence from the mesic grassland soil seed bank. A greater number of fire-loving Themeda triandra seedlings emerged from soils treated with smoke, though this was not statistically significant. Seedling emergence indicators showed that seedling emergence was favoured more by smoke and smoke + heat treatments compared to the control. Seedling growth indicators also showed that soil samples treated with smoke or smoke + heat combined produced significantly higher biomass than untreated samples. In general, findings from this comprehensive study suggest that plant-derived smoke and its interaction with temperature (heat) and soil nutrients significantly influences seed germination and seedling growth of South African mesic grassland species differently, this can further influence the grassland composition. The association of certain fire-climax species with the re-occurrence of fire can partly be explained due to the association of such species with fire-induced changes in the habitat. Post-fire conditions of low nutrient (NPK) availability, presence of high heat and smoke cues in the habitat may favour the competitive ability of native short and smoke-responsive species such as Themeda triandra and Tristachya leucothrix over those characteristic species of fertile habitats such as Eragrostis curvula and other non-smoke-responsive species.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

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39

Peden, Moraig Isobel. "The impact of communal land-use on the biodiversity of a conserved grassland at Cathedral Peak, uKhahlamba-Drakensberg Park, South Africa : implications for sustainable utilization of montane grasslands." Thesis, 2004. http://hdl.handle.net/10413/5448.

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South African grasslands are under-conserved and there is a need to expand conservation efforts beyond the boundaries of protected areas. While communal grasslands have conservation potential they are generally over-utilized and the impact of communal land-use on biodiversity is poorly studied. At the same time there is pressure on protected areas to allow for the sustainable utilization of biodiversity. The aim of this study was to examine the impact of communal land-use on various components of biodiversity and to make recommendations regarding communal use of protected areas. A fence-line study was conducted to assess the impact of eight years of controlled communal land-use on biodiversity in the uKhahlamba-Drakensberg Park. The communally used land (referred to as the lease land) which was used for controlled grazing as well as plant collection was compared with land under formal conservation. Vegetation was sampled using the importance score method and veld condition assessments. Selected invertebrate taxa were sampled using sweep netting, colour pan traps and transects and were identified to morphospecies level. Multivariate statistics revealed that sites generally grouped according to landscape position rather than land-use. No significant differences were found in diversity, evenness, richness or veld condition between the lease and conservation land. However, more than twenty-five percent of vegetation and invertebrate species were found exclusively in the lease or conservation land, suggesting that different suites of species were supported by the two landuses. Four alien plant species were found exclusively in the lease land, while one vulnerable and one rare plant species were found only in the conservation land. Further research is required to assess whether biodiversity was diminished by controlled communal. While the lease concept may offer potential as a low-use buffer zone, localised damage from cattle paths and weak enforcement of grazing agreements were areas of concern. Keywords: communal grass)ands, grassland flora, grassland invertebrates, transfrontier park.
Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

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40

Kathawaroo, Deshika. "The nutrient status of grasslands and adjacent Pinus patula and Eucalyptus grandis plantations on the eastern escarpment of South Africa." Thesis, 2006. http://hdl.handle.net/10539/234.

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Master of Science - Science
The replacement of indigenous grasslands by commercial forestry plantations on the mountainous eastern escarpment of South Africa, has inevitably led to alteration of nutrient cycling. The overall objective of this study was to determine the nutrient status (soil, litter and foliar nutrient concentrations) of Pinus patula and Eucalyptus grandis plantations and adjacent grasslands. The 2, 13 and 30 year old P. patula plantations and adjacent Driekop grassland were located relatively high up on the escarpment (altitudes ranging between 950–1610 m) and were underlain by dolomite while the 2, 8 and 13 year old E. grandis plantations and adjacent Brooklands grassland were located lower down (altitudes ranging between 900–1100 m) and were underlain by granite. It was assumed that the nutrient status of the soil under the plantations and the adjacent grasslands were similar prior to afforestation. Samples were collected once in winter (August 2002) and once in summer (January 2003). Soil samples were collected to a depth of 20 cm and litter material, to a maximum depth of 20cm. Lower canopy foliar samples were collected within the lowermost metre of the canopies and upper canopy foliar samples were collected within the uppermost metre of the canopies. The data were analysed in the laboratory for various elements and soil physical parameters. The soil pH was lower under the P. patula (pH 4.8-5.2) and E. grandis plantations (pH 4.6-5.3) when compared with the soil under the adjacent grasslands (pH 5.3-5.6). The soil under the P. patula plantations had lower exchangeable base cation concentrations (204-300 mg kg-1) compared with the adjacent Driekop grassland (452-645 mg kg-1), while there were no clear trends when comparing the exchangeable basic cation concentrations in the E. grandis plantations and the adjacent Brooklands grassland. The soil aluminium saturation was similar between the plantations, ranging between 39.7 and 63.3% in the P. patula plantations and 27.4 and 75.6% in the E. grandis plantations. The grasslands had lower soil aluminium saturations, ranging between 17.7 and 35.7% in the Driekop grassland and 17.5 and 39.1% in the Brooklands grassland. Exudates from mycorrhizal associations chelate iv acidic cations, rendering plantations more tolerant of acidic soils. Soil total nitrogen, phosphorus and carbon in the plantations were similar to the adjacent grasslands. Higher nitrogen mineralisation rates in the P. patula plantations corresponded with higher litter and foliar total N concentrations relative to the adjacent Driekop grassland, while there were no clear trends when comparing rates of N mineralisation in the E. grandis plantations and the Brooklands grassland. The concentrations of foliar amino acids and protein were significantly higher (p<0.01) in the plantation foliage, when compared the grassland foliage. The amino acid arginine, occurred in higher proportions relative to other amino acids in plantation foliage, when compared with the relative proportions found in the grasslands. Relative to nitrogen, foliar ratios indicated that phosphorus and potassium were the most limiting nutrients for the plantations, which possibly resulted in N storage in the form of protein and amino acids. The soil and foliage were the more sensitive indicators of the nutrients status than litter. Differences in nutrients concentrations between the lower and upper canopies in both plantations were minor and no major trends were found. Therefore the sub division of lower and upper canopies is not recommended for further foliar nutrient analyses. Age related trends were unclear as a result of higher soil clay contents found in the 13 year old P. patula plantation and the 8 year old E. grandis plantation as well as the various silvicultural practices implemented. In terms of the relative impacts of P. patula and E. grandis plantations, the results of this study imply that the upper 20cm of soil was more impacted under the P. patula plantations than under the E. grandis plantations, in terms of reduced base cation and increased acid cation concentrations. The P. patula plantations are shallow rooters and thus the base cation status of the upper soil horizons may affect the sustainability of the P. patula plantations.

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Madilonga, Mpho Given. "Population biology and ecology of Vachellia karroo (Hayne) Banfi and Galasso in the Nylsvley Nature Reserve, Limpopo Province, South Africa." Diss., 2017. http://hdl.handle.net/11602/951.

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MSc (Botany)
Department of Botany
Plant populations are determined by many elements that impose demographic filters. Following disturbance, in African savanna woodland trees regenerate both sexually and vegetatively. Vachellia karroo (Hayne) Banfi and Galasso, family Fabaceae and sub family Mimosideae, commonly known as “sweet thorn” or “soetdoring” (Afrikaans), is a leguminous shrub common throughout Southern Africa. Its distribution range is from the Southwestern Cape northwards into Namibia, Angola, Botswana, Zambia and Zimbabwe. It is a pioneer species and has the ability to encroach rapidly into grassland grazing areas. Therefore, V. karroo is considered the most important woody invader of grasslands in South Africa. This study aimed at investigating the population biology and ecology of V. karroo in the clay waterlogged site of the Nylsvley Nature Reserve. Plant height, stem circumference, canopy cover, distance between individuals were measured and disturbance levels on individuals of V. karroo were estimated during sampling. The results showed that the population of V. karroo display an adequate growth curve thus implying that the population of V. karroo in the Nylsvley Nature Reserve is healthy and viable. More mature healthy individuals were found in September and December, than during June and July; this is obviously because early summer season, and in September most of the savanna plant species were starting to actively recover from the winter dry season. This is confirmation enough that the population of V. karroo is expanding in the clay waterlogged areas of Nylsvley Nature Reserve.

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Dalton, Brian Patrick Alexander. "The coastal grasslands of Maputaland, South Africa : effects of fire and grazing on vegetation structure, diversity, and composition." Thesis, 2007. http://hdl.handle.net/10413/10764.

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A series of trials and investigations were implemented to address concerns surrounding the dynamics of the fire-climax wooded/edaphic grasslands within the iSimangaliso Wetland Park, northern KwaZulu-Natal, South Africa. The research problem surrounded inadequate historical evaluations of changes in vegetation structure, grasslands progressing to a woody dominated composition, and increases in Helichrysum kraussii (Curry bush). These were addressed as follows: Firstly, the recovery of vegetation in response to different periods of fire exclusion in different communities along a topographical gradient of a coastal dune area, was assessed over a two year period. Secondly, the regeneration after wildfire of the persistent, stress tolerant shrub H. kraussii, was studied on different catenal positions with differing fire exclusion periods and with and without defoliation of surrounding plant biomass in the coastal edaphic grasslands north of Manzengwenya, South Africa. Thirdly, aerial photography from 1937, 1975, and 2000 was georectified, digitised and analysed using a Geographic Information System to examine broad vegetation changes in response to different management regimes for a site on the Eastern Shores of Lake St Lucia and a site within the Tewate Wilderness Area. In the absence of fire, the coastal edaphic grasslands progressed to a closed canopied scrub forest within six years. An increase in fire exclusion period resulted in a decrease in species abundance, an increase in woody height, and a decrease in plant density. Richness increased initially but declined marginally with increased fire exclusion period. Higher lying east and west facing sites had a better veld condition index compared with bottom sites and had an increased response (vigour) to defoliation but were far more likely to succeed through to woody scrub forest. Woody plant biomass vigour was greater for west facing sites. Ordination of species composition across sites in response to fire exclusion and catenal position revealed greater similarities within exclusion periods than between. Bottom sites were more similar with similarity decreasing for east and west facing sites. Fire exclusion resulted in an initial increase in woody species and a subsequent increase in herbaceous species. iii Growth response of H. kraussii was unaffected by catenal position and fire exclusion period, whereas defoliation of surrounding grass tended to increase in size (P<0.05). Density and height for this species however increased with increasing fire exclusion. An increase in soil moisture negatively affected H. kraussii growth indicating susceptibility to high water tables. The number of other woody species establishing beneath H. kraussii may be due to changes in the transmission of light through the canopy where an increase in canopy diameter resulted in an increase of photosynthetically active radiation at the soil surface. The effects of fire on landscape change were investigated for the Eastern Shores and Tewate Wilderness Area, iSimangaliso Wetland Park, South Africa using aerial photography. Changes to historical disturbance regimes largely through active exclusion of fire resulted in the majority of the higher lying coastal grasslands changing to savanna scrub or closed canopied forest within 63 years on the Eastern Shores. The degree of fragmentation of these grasslands was greatly reduced within the Tewate Wilderness Area where disturbance regimes included greater frequencies of fire. Hygrophilous grasslands remained largely unaffected by woody encroachment but did not preclude woody species establishment indicating possible susceptibility during long drier periods. Frequent fires result in the maintained distribution of the higher grasslands. This vegetation type is a system which becomes resilient in response to fire, whereas in the absence of fire readily progresses to Dune Forest. The coastal grasslands above the high water table are therefore highly unstable and transformed easily in the absence of regular disturbance. It would appear that a threshold of approximately six years exists, after which substantial management intervention may be required to reverse the succession back to grassland. The growth of H. kraussii was unaffected by fire and remained persistent irrespective of fire exclusion period. An ability to attain size (height and canopy diameter) was limited with increased soil moisture but density was reduced through regular burning. Frequent fires are necessary to reduce density of H. kraussii and reduce the competitive advantage gained with age.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

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43

Helm, Chantal Vinisia. "Ecological separation of the black and blue wildebeest on Ezemvelo Nature Reserve in the highveld grasslands of South Africa." Diss., 2007. http://hdl.handle.net/2263/28345.

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The present study was conducted on Ezemvelo Nature Reserve in the highveld grasslands of South Africa. The evidence for ecological separation between the black and blue wildebeest was investigated in an area with suboptimal habitat for both types of wildebeest. Habitat selection and separation of the black and blue wildebeest population were investigated at three main scales. A combination of logistic regression analysis, discriminant analysis and hypothesis testing techniques were used to determine whether habitat separation occurred between the black and blue wildebeest at the various scales. Seasonal, social group and weather influences on the habitat selection of both types of wildebeest were also investigated. Black and blue wildebeest showed resource partitioning in terms of habitat at the macro and mesoscales but not at the microscale. The preference for open areas by the black wildebeest and its more specialised territoriality were found to be the main driving factors contributing to the habitat separation of the two types of wildebeest. The population of black wildebeest was found to be decreasing while the blue wildebeest population was found to be increasing in the study area during the study period. Spatial overlap between the black and blue wildebeest was found to be low. Little evidence of interference interspecific competition between the black and blue wildebeest was found. It was, however, concluded that exploitative competition between the two types of wildebeest would be found in areas with low habitat heterogeneity. Ecological separation between the black and blue wildebeest was found to be incomplete. However, the coexistence of the black and blue wildebeest was deemed possible provided habitat heterogeneity in terms of the factors found to be important for habitat separation was high and population sizes were strictly monitored and actively controlled. Finally, a number of additional management recommendations for the black and blue wildebeest at Ezemvelo Nature Reserve and for other reserves confining both types of wildebeest together based on the results of this study were made.
Dissertation (MSc (Wildlife Management))--University of Pretoria, 2007.
Animal and Wildlife Sciences
MSc
unrestricted

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Coombes, Peter John. "Development of a grassland monitoring system for the management of the wolkberg wilderness area." Thesis, 1991. http://hdl.handle.net/10539/22949.

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A thesis submitted to the Faculty of Science, University of the Wiwatersrand, Johannesburg, for the degree of Master of Science.
This study aimed to investigate, within the contemporary philosophy of science, key aspects of the paradigm formulated by the national Vegetation Monitoring Work team (VMW), and thereby develop a grassland monitoring system to place. the management of the Wolkberg Wilderness Area (WWA) on a testable basis. ( Abbreviation abstract )
AC2017

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45

Lee-Thorp, Julia A., J. Luyt, and M. B. Sponheimer. "Tracking changing environments using stable carbon isotopes in fossil tooth enamel: an example from the South African hominin sites." 2007. http://hdl.handle.net/10454/3432.

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No
The environmental contexts of the karstic hominin sites in South Africa have been established largely by means of faunal associations; taken together these data suggest a trend from relatively closed and more mesic to open, drier environments from about 3 to 1.5 Ma. Vrba argued for a major shift within this trend ca. 2.4¿2.6 Ma, an influential proposal that posited links between bovid (and hominin) radiation in Africa and the intensification of Northern Hemisphere Glaciation. Yet faunal approaches often rely on habitat and feeding preferences of modern taxa that may differ from those of their extinct predecessors. Here we explore ways of extending 13C/12C data from fossil mammals beyond denoting ¿presence¿ or ¿absence¿ of C4 grasses using the evolution of open environments in South Africa as a case study. To do so we calculated the relative proportions of C3-, mixed-, and C4-feeding herbivores for all the hominin sites for which we have sufficient data based on 13C/12C analyses of fossil tooth enamel. The results confirm a general trend towards more open environments since 3 Ma, but they also emphasize a marked change to open grassy habitats in the latest Pliocene/early Pleistocene. Mean 13C/12C for large felids also mirrored this trend.

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Mochesane, Moseketsi Valencia. "Plant diversity in grassland of selected nature reserves and adjacent grazing areas within the Gauteng province , South Africa." Diss., 2019. http://hdl.handle.net/10500/26144.

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The relations between environmental resources and biodiversity are crucial in the proper management and conservation of grasslands. Three nature reserves were chosen around the Gauteng Province, namely Roodeplaat Nature Reserve (RNR) in Tshwane, Suikerbosrand Nature Reserve (SNR) in Heidelberg, and Abe Bailey Nature Reserve (ANR) in Carletonville. We selected three sites within RNR, SNR and ANR, and paired these with adjacent sites in private farming/grazing areas adjacent to the nature reserves. At each site, species composition, species richness and plant diversity were determined with the use of 50m x 20m Modified-Whittaker plots (MWP), making a total of eighteen plots (MWP) at the nine paired sites. Two paired sites had high Shannon-Wiener Index (H’) average values at the adjacent grazing area as compared to the nature reserve area at ANR. Roodeplaat Nature Reserve (RNR) and Suikerbosrand Nature Reserve (SNR) had two paired sites with high H’ average values in the nature reserve as compared to the adjacent grazing area. The vegetation structure was similar for the three study locations, consisting of graminoids, herbs and isolated patches of shrubs. The species composition showed similarities between ANR and SNR sites, while RNR showed different species composition. SNR soils had the highest organic carbon (OC), total Carbon (C), total Nitrogen (N), Calcium (Ca), Potassium (K), Magnesium (Mg) and Sodium (Na) as compared to both ANR and RNR. Species richness had a significantly positive relationship with Organic Carbon and Total Nitrogen. Species diversity difference was detected between the nature reserves and adjacent grazing areas and the difference are likely due to a number of factors including soil properties, land disturbance and land use and management. More research is necessary to further understand the aspects impacting species richness, species diversity and species composition in grasslands.
School of Agriculture and Life Sciences
M. Sc.

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Berruti, Sharron Marion. "Vegetation ecology of Drakensberg foothill moist grassland on Hlogoma Mountain, Underberg, KwaZulu-Natal." Diss., 2017. http://hdl.handle.net/10500/23833.

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Hlogoma Mountain is a small inselberg surrounded by farms and commercial forestry in the Underberg district (KwaZulu-Natal) within the Gs10 Drakensberg Foothill Moist Grassland. As little is known about the vegetation on Hlogoma, a survey was undertaken to classify, map and describe the plant communities occurring on the inselberg. A total of 100 (16 m2) randomly stratified sample plots were placed in homogeneous vegetation units within the 117 ha study area. A TWINSPAN classification, refined by Braun-Blanquet procedures, resulted in the identification of two major communities, five communities, 12 sub-communities and four variants. All communities were described and a vegetation map constructed. Ordinations identified key environmental variables that have an impact on the vegetation at the study site. A plant species checklist was created and analysed for floristic composition; rarity and threatened species; medicinal plants; endemism; phenology; flower colour and elevation range; species richness and plant community biodiversity. A total of 467 species were identified, represented by 271 genera and 87 families. Four Red Data species and a new Aspidoglossum species were discovered. Two near-endemic genera, two endemic species and 88 near-endemic species belonging to the Drakensberg Alpine Centre were found on Hlogoma. This study showed that Hlogoma Mountain is an inselberg with high plant species richness and endemism, and is a refuge of conservation importance for biodiversity.
Environmental Sciences
M. Sc.(Environmental Science)

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Mogashoa, Regina Etla. "Bush encroachment effects on above-ground biomass, species, composition, plant diversity and selected soil properties in a semi-arid savanna grassland." Thesis, 2020. http://hdl.handle.net/10386/3394.

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Thesis (M.Sc. Agriculture (Pasture Science)) -- University of Limpopo, 2020
Bush encroachment is a major problem in arid and semi-arid savannas characterized by a grass layer interspersed with a shrub stratum. Land cover change as a result of rapid proliferation of woody species in previously open rangelands alters herbaceous species and impacts soil properties. So far, little is known about the threshold at which woody plant density and cover affects herbaceous cover and the underlying mechanisms driving bush encroachment in arid and semi-arid rangelands are still debated. The objectives of this dissertation were to (1) to assess woody species composition and structure along an encroachment gradient and to explore the relationship between woody vegetation and herbaceous vegetation. (2) To determine the effect of increasing tree density and cover on grass species richness, diversity, evenness and selected soil nutrients in a bush encroached rangeland. In order to address these objectives, a semi-arid rangeland was demarcated into three encroachment gradients spanning from open to intermediate and intensive. Within each encroachment gradient six plots of 10 m x 10 m were randomly selected, whereby woody and herbaceous vegetation were assessed and soil properties determined. A discernible increase in woody species diversity and evenness was found along the transition from open to intensive bush encroached rangeland. Leguminous woody species Vachellia spp. and Dichrostachys cinerea were dominant along the bush encroachment gradient. Tree height was found to be positively correlated with long crown diameter (LCD) and short crown diameter (SCD). Furthermore, increasing tree density resulted in a 53% decline in grass species richness (GR). A decline in GR mirrored an increase in the composition of the decreaser species Panicum maximum (90%). Increasing woody plant density and cover also increased macro-nutrients; total carbon, nitrogen, phosphorus, exchangeable calcium and magnesium by 21%-159% in the shallow rangeland soils. Such quantitative information will assist rangeland managers to better understand the effects of varying bush encroachment intensities on herbaceous species composition, richness and soil properties in semi-arid savanna rangelands.

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Skhosana, Felix Vusumuzi. "Fire-grazer interactions in a Highveld grassland in South Africa." Thesis, 2017. https://hdl.handle.net/10539/25065.

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A dissertation submitted to the Faculty of Science in fulfilment of the requirements for the Master of Science degree. in School of Animal, Plant and Environmental Sciences, University of The Witwatersrand, Johannesburg July 2017.
Fire is known to affect spatial patterns of grazing by altering the amount and quality of forage. Animals select the post-burn green flush that remains palatable until the grass recovers its biomass. How quickly the grass regrows depends on the rainfall and grass growth rates, and also grazing intensity. Theoretically, highly concentrated grazing can maintain short (relatively more palatable) grasslands throughout a growing season. Therefore this study aimed at; i) determining how long different grazer species were attracted to the burn, and whether this increased grazing pressure (as a result of concentrating grazers on a small burnt patch) maintained a short, palatable grass sward throughout the growing season, ii) investigating the long-term impacts of herbivore attraction to small burns on grass community and landscape function in a Highveld grassland. We therefore monitored grazer utilization of an experimentally applied small (5ha) burnt patch using dung counts and camera traps, and also measured the structural changes of the burnt patch over a period of 12 months. To test whether this process of attraction to small burns could have long-term impacts on grass community composition and landscape function we quantified species composition, infiltration rates, soil compaction, soil moisture, and ANPP in another landscape which had received 10+ years of small annual burns (a firebreak). A novel finding was that indeed grazers especially the short-grass specialist stayed on the burn and kept the grass short (<10cm) for the duration of the study post fire: the burn only treatment on the 5ha burn recovered its biomass within 2 months of the first rains. This result was due to the fact that it was a drought year with half the normal rainfall (and lower grass regrowth rates). However, the long-term study indicated that the attractive effect of small fires in this ecosystem alters both community composition and ecosystem properties. The firebreak had more bare ground and less water infiltration than the surrounding grassland – but was more diverse and had higher grass productivity. It also continued to attract the short-grass specialist species (blesbok, wildebeest and hartebeest). This counter-intuitive result indicates that perhaps these grasslands are not as severely degraded as we think. This study therefore, showed that coupling small burns with appropriate grazer species has a great potential for creating palatable grazing “hotspots”, in sourveld grassland without obvious damage to ecosystem function.
LG2018

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Matsika, Ruwadzano. "Land-cover change: threats to the grassland biome of South Africa." Thesis, 2008. http://hdl.handle.net/10539/4759.

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The Grassland biome of South Africa has been identified as critically endangered and the biome in South Africa most requiring conservation attention through the implementation of efficient, sustainable systematic conservation plans. The ability to predict where land-cover transformation as well as information on the occurrence and severity of current land cover transformation activities, as threats to biodiversity, is required as part of the systematic conservation planning process. Neke & du Plessis (2004) predicted land cover transformation and the severity of the impact on biodiversity in the Grassland biome. This model was based on potential land use suitability models and land cover information for the 1994/5 season extracted from the National Land Cover database (NLC1994). These predictions were tested by assessing actual land cover change in the Grassland biome using observed differences in grassland land cover between the NLC1994 and NLC2000 databases. Methodology Because of differences in format and land-cover classification between the original datasets, both NLC1994 and NLC2000 had to be modified before any analyses could be carried out. These differences exist because different techniques were used to collate the respective datasets, thus introducing the potential for significant mapping error in the original datasets and more significantly erroneous results with respect to landcover change detection. The implications of this were presented in the discussion. Both datasets were spatially resampled and class-standardised and it was felt that this would significantly reduce any the impact of any such existing errords in the original datasets. Thereafter landcover information for the Grassland biome was be extracted and the comparative landcover analyses executed. The analyses carried out included: • Landcover change per landcover class within the Grassland biome with emphasis on the Grassland landclass losses and gains • An assessment and comparison of the relative fragmentation of the remaining grassland patches in both datasets • An assessment of current grassland habitat degradation • The comparison of the predicted land cover change as given by Neke & du Plessis (2004) against the observed grassland changes • The creation of a new Grassland Transformation threat map reflecting current land cover change threats, and including information pertaining to the threats to Grassland biodiversity posed by invasive alien plants, road effects, urban areas and soil erosion hazards. Results and Discussion 25% of the remaining grassland patches underwent transformation to other land classes. Grassland clearing for cultivation, bush encroachment and bushland vegetation regeneration were the main causal factors behind the observed grassland losses. However, grassland vegetation regeneration on formerly cultivated land, bush clearing and reclassification of degraded lands as grasslands in the NLC2000 dataset contributed to a net 2% gain in area of the grassland land class. The remaining grassland patches are more fragmented than they were in NLC1994, the average patch size (NLC2000) is three times smaller and the total number of grassland patches has increased (also by a factor of 3) and the remaining grassland patches are more isolated. The largest, least fragmented grassland patches occur along and to the west of the Great Escarpment as it traverses the Grassland biome. Most of the predictions of grassland transformation were realised, however the model used by Neke & du Plessis (2004) consistently underestimated and in some cases failed to predict the occurrence of grassland transformation in the central interior of the Grassland biome. Current, measurable human activities that act as grassland transformation agents were incorporated to create a threat map showing the extent and severity of land-cover transformation activities within the biome; grassland bird species richness information was then incorporated into this map to create biodiversity transformation threat map. This map was used to show the location and severity of the impacts of human transformation activities on grassland biodiversity. Both transformation threat map reflect the current situation across the biome today and were compared against the Potential transformation threat map produced by Neke & du Plessis (2004). The human transformation threat map confirmed the inability of the Neke & du Plessis model to make correct predictions of land cover change away from the eastern, 7 high altitude boundary of the biome. Given that the biome is defined by its climatic characteristics, the incorporation of global climate change effects would further refine the results gained, and perhaps provide more accurate predictions. As aforementioned, there are however factors existing within the original datasets used in this analysis that may have affected the accuracy of the landcover change analyses. These factors are centred on the potential effects of mapping errors within either of the NLC datasets. The delineation of landclass boundaries in the NLC1994 dataset is one such factor- placing a line over what is in reality a gradient of changing vegetation, is a subjective exercise and depends entirely on the technician involved this in itself may have introduced a fair amount of error in the mapping process. When coupled with the automated classification techniques used, for the most part, for the NLC2000 dataset, it becomes apparent that it is highly unlikely that even in the absence of actual landcover change the same boundaries would be drawn between two landclasses in the same area. This would provide false positive results for landcover change where in fact this is as a result of mapping errors. This is acknowledged and included in the interpretation of the results and it is felt that in spite of this, all possible steps were taken to minimize the impact of these effects on the reslults. The analysis allowed the identification of the current land cover transformations leading to grassland loss. However, land-cover change is only the physical expression of the complex interactions between socio-economic factors. To create effective and sustainable conservation plan for the Grassland biome, with an aim to reducing habitat loss requires an action plan to address these factors as the ultimate drivers of land cover change.

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Dissertations / Theses on the topic 'Grasslands – South Africa'

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