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

The natural vegetation of the Cradle of Humankind World Heritage Site (COH WHS) was classified using Braun-blanquet methodology. This identified 22 distinct plant communities and 2 variants. Sampling took place over two growing seasons with a total of 91 releves being compiled. A stratified random approach to sampling used Land Types as a means of primary area stratification, with terrain position providing the means for further refinement. The grassland comprised of 12 plant communities and 2 variants and the woodland comprised of 10 plant communities. The classification of the woodland areas included some bush clumps associated with the entrances of caves which were also described independently in which seven distinct plant communities were identified A positive linear correlation exists between the size of the cave entrances and the extent to which the surrounding woody vegetation extends. This suggests the likelihood of cave entrance size influencing the surrounding vegetation. / Environmental Sciences / M. Tech. (Nature Conservation)

A thesis submi.tted to the Faculty of Science, University of the witwatersrand, Johannesburg I in the fulfillmen,,;"o:f' 't\ :he requirements of the Degree of Magister Scienta~. June 1992 / The present study was undertaken; withirl the South African " savannas, to provide "insight into a j;unctional classification of aavanna plants using ecophY$iologiLcal charact~:t's.THe pri.mary r.:>bjective of this study Was to investigate the vari.ation of these tt'aits throughout: the savanna, aridto relate this variation to plant avail.able moisture and nU~l'ie~~s• !t was conclu.ded that~ 1) no formal or specialized strategies have evolved within a number of the study sites, .2) unlike the woody component I neither divergellce nor convergence was demonstrated within the grass layer, c' 3) plant aVailable nutrients did not appear to be a major determinant of either component. Although plant available moistur~ proved to be unimportant in the woody layer, it did playa role as a determinant of the grass layer, and 4) constancy of the plant traits was not demonstrated to \": OCCllr over the gr~~ing season. A succeisf',\lclassification' would require the components to be separat~pl specific determinan.ts be identified for each component, and an element of time be included into both edaphic and biotic measurements.

The natural vegetation of the Cradle of Humankind World Heritage Site (COH WHS) was classified using Braun-blanquet methodology. This identified 22 distinct plant communities and 2 variants. Sampling took place over two growing seasons with a total of 91 releves being compiled. A stratified random approach to sampling used Land Types as a means of primary area stratification, with terrain position providing the means for further refinement. The grassland comprised of 12 plant communities and 2 variants and the woodland comprised of 10 plant communities. The classification of the woodland areas included some bush clumps associated with the entrances of caves which were also described independently in which seven distinct plant communities were identified A positive linear correlation exists between the size of the cave entrances and the extent to which the surrounding woody vegetation extends. This suggests the likelihood of cave entrance size influencing the surrounding vegetation. / Environmental Sciences / M. Tech. (Nature Conservation)

The area studied at Fern Kloof, near Grahamstown, consists of a strip of vegetation approximately 260 yds. long and 50 yds. wide, in which there are two communities: 1) indigenous forest 2) exotic Pine forest (which has only one tree species Pinus pinaster). Throughout the thesis this species is referred to as the pine. The object of the investigation has been to determine whether these communities are natural or not. This has involved a study of the floristic composition, the life forms and the structure of the plant communities. In addition, various soil and environmental factors have been studied.

Tesis (MSc) -- Stellenbosch University, 1995. / ENGLISH ABSTRACT: A map of the different plant communities in a part of the West Coast National Park (WCNP) is presented. The approach of the Zurich-Montpellier school is used for the phytosociological studies. Thirty plant communities are described and related to environmental factors. One new alliance, two sub-alliances, seventeen associations, seven sub-associations and three variations are described. It is suggested that the Willdenowio -- Diospyretum austro-africanae is raised to alliance level and the Eucleo -- lschyrolepion eleocharidis lowered to sub-alliance level. The different floristic groups in which the plant communities fell were Strandveld, Proto-fynbos, marsh, strand and ecotones between Strandveld and Fynbos. A further extensive survey was conducted in the Postberg Nature Reserve (PNR), which forms part of the West Coast National Park, to determine the possible cause of decline in small antelope numbers (duiker, grysbok and steenbok). The potential production of the vegetation of the Postberg Nature Reserve is about 561.64 kg DM/ha/yr. Rumen analyses of the small antelopes were performed in an attempt to assess the possible relationship between plants and animals. It is found that the small antelope utilizes a big spectrum of plants. Different plant communities were structurally examined and it is proved that the steenbok are bolder than the other two small antelope and are prepared to feed in areas having a lower plant density. Duiker and grysbok preferentially prefer plant communities taller than 60 cm. KEYWORDS Braun-Blanquet, community structure, distribution, Fynbos Biome, habitat, plant communities, Raphicerus campestris, Raphicerus melanotis, Strandveld, Sylvicapra grimmia. / AFRIKAANSE OPSOMMING: 'n Plantgemeenskapskaart is vir 'n deel van die Weskus Nasionale Park (WNP) opgetrek. Die Zurich-Montpellier fitososiologiese benadering is gebruik om die plantegroei te analiseer en te beskrywe. Dertig plantgemeenskappe is geklassifiseer, beskryf, gekarakteriseer en ekologies geinterpreteer. Ben nu we alliansie, twee sub-alliansies, sewentien assosiasies, sewe subassosiasies en drie variasies is beskryf. Daar is voorgestel dat die Willdenowio -- Diospyretum austro-africanae tot alliansievlak verhoog en die Eucleo -- Ischyrolepion eleocharidis na suballiansievlak verlaag word. Die verskillende floristiese groepe waarin hierdie plantgemeenskappe geval het bestaan uit Strandveld, Protofynbos, strand-, vleiland-, en ekotone tussen Strandveld en Fynbos. 'n Verdere intensiewe studie is in die Postberg Natuurreservaat (PNR), wat deel uitmaak van die Weskus Nasionale Park, ondemeem om 'n moontlike verklaring te vind vir die afname van kleinwildsoorte (duiker, grysbok en steenbok). Die produksiepotensiaal van die Postberg Natuurreservaat (PNR) is bepaal op ongeveer 561.64 kg DM/ha/jaar. Maaginhoud ontledings van die kleinwildsoorte is gebruik om 'n moontlike verhouding tussen plant en dier te bepaal. Daar is bevind dat die kleinwildsoorte 'n groot spektrum van plante kan benut. Verskillende plantgemeenskappe is t.o.v. plantegroeistruktuur ondersoek en daar is bewys dat die steenbok minder skugter as die grysbok en duiker is en in oop areas, met 'n laer plantdigtheid, sal beweeg. Die duiker en grysbok verkies plantgemeenskappe wat meer as 60 cm hoog is. TREFWOORDE Braun-Blanquet, Fynbosbioom, gemeenskapstruktuur, habitat, plantgemeenskappe, Raphicerus campestris, Raphicerus melanotis, Strandveld, Sylvicapra grimmia, verspreiding.

Elephants (Loxodonta africana, Blumenbach) are recognised as keystone herbivores and ecosystem engineers in African ecosystems due to the noticeable impact they have on plant communities. This impact can influence other animal taxa and ecosystem processes, especially within enclosed systems. I investigated the effects of elephants in four vegetation types and the cascade effect on three associated taxa and two ecosystem processes at five sites with elephants and five paired sites without elephants in the Eastern Cape Province, South Africa, between April 2005 and July 2007. In grassland habitats, the physical structure of the vegetation was neither enhanced nor degraded in the presence of elephants. Within the locally important Thicket Biome, elephant browsing transformed relatively homogeneous stands of vegetation into more heterogeneous units. However, although seeds from thicket plant species were recorded in elephant dung, elephants did not promote the viability and germination success of these plants. In addition, elephant foraging on aloes caused declines in their populations. By contrast, the size of bushclumps was not reduced in the presence of elephants in bushclump savanna. The associated insect, bird and mammal communities appeared to benefit from elephant foraging in all vegetation types assessed, whereas vegetation patch dynamics and soil surface processes were neither enhanced nor degraded in the presence of elephants. I conclude that, at current densities, elephants do not (in most cases) negatively affect plant and animal communities or ecosystem processes in enclosed reserves. However, elephants have only been present at each site for a relatively short period and it is likely that their impact will be cumulative, increasing over time in these closed systems. Thus, future research along a continuum of elephant density and time since re-introduction is recommended.

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)

A vegetation survey was conducted on the newly acquired farm portions of the farm Doornrandje 386 JR, which are being incorporated into Gauteng Department of Agriculture and Rural Development’s protected area expansion. This study provides an ecological basis for establishing an efficient management programme for the area. From a TWINSPAN classification, refined by Braun-Blanquet procedures, five plant communities were identified. A classification and description of the major plant communities is presented. Descriptions of the plant communities include characteristic species, as well as prominent and less conspicuous species of the tree, shrub, herb and grass strata. Floristic analyses of the vegetation and a biodiversity comparison of the different plant communities found on the farm are also undertaken. This study proves that the extended land incorporated into the Reserve contributes to the biological diversity of the study area. / Environmental Sciences / M. Sc. (Environmental Science)

A vegetation survey was conducted on the newly acquired farm portions of the farm Doornrandje 386 JR, which are being incorporated into Gauteng Department of Agriculture and Rural Development’s protected area expansion. This study provides an ecological basis for establishing an efficient management programme for the area. From a TWINSPAN classification, refined by Braun-Blanquet procedures, five plant communities were identified. A classification and description of the major plant communities is presented. Descriptions of the plant communities include characteristic species, as well as prominent and less conspicuous species of the tree, shrub, herb and grass strata. Floristic analyses of the vegetation and a biodiversity comparison of the different plant communities found on the farm are also undertaken. This study proves that the extended land incorporated into the Reserve contributes to the biological diversity of the study area. / Environmental Sciences / M. Sc. (Environmental Science)