Dissertations / Theses on the topic 'Plant invasion – South Africa – Limpopo'

South Africa generates more than 90 percent of its total energy capacity through non-renewable sources. With coal forming the predominant energy source, South Africa became the leading carbon emissive nation in Africa, emitting 450 million tonnes of CO2 in 2011. In an international effort to restrict global average temperature rise to 2° C above the average prior the industrial revolution, the Kyoto Protocol has been extended for another 8-year commitment period. This is complementary to an expected resolution of a new legally binding climate change policy in 2015. This policy will aim to introduce financial penalties for nations failing to meet ascribed GHG emission targets by 2020. In an attempt to meet these climate change resolutions South Africa will research and develop cleaner, alternative forms of energy, including hydro, wind, and biomass forms of renewable energy, in addition to designating stringent building regulations for the Incorporation of solar energy. These measures form part of an Integrated evelopment Plan that aims to generate a target of 10,000 GWh of renewable energy in 2013. South Africa is also investigating the possibilities of extracting its shale gas reserves and implementing it as a major energy source. This energy mix has given little attention to geothermal energy. The reasons for this omission appears to be the lack of active volcanism and previous research that suggests South Africa, largely underlain by the Kaapvaal Craton, has a relatively low heat Flow profile, deemed insufficient for harnessing geothermal energy.

Thesis (MSc)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: With only 1.76% conserved West Coast Renosterveld remaining it is crucial to prioritize the conservation and management of this fragile vegetation type. Because of its occurrence on fertile soils, renosterveld has been cleared for cultivation and other agricultural use and is thus fragmented to a critical point. These remaining fragments are subject to extensive edge effects and the exact parameters of a viable fragment must still be determined. The extent of alien grass species invasion into remnant renosterveld patches was determined using data collected using the line-intercept method. Sampling included three different management treatment areas adjacent to old lands: 1) a recently burned area, 2) a grazed area and 3) an unburnedlungrazed area providing a control sample. Additionally all small-scale soil disturbances along the lines were recorded. Results showed that Briza spp., Bromus spp. and Avena fatua were the most significant invading alien grass species. There was a significantly high variation between alien grass cover in each treatment, with the grazed area containing the highest overal! level of alien grass invasion. The control area, with the exclusion of fire and animal activity, showed minimum alien grass invasion. Edge effects were apparent in all treatments, but were lowest in the control area, where percentage alien grass cover significantly decreased after a distance of fifteen meters into the remnant patch. A weak positive correlation between the occurrence of alien grass and indigenous grass was found, as well as evidence of a weak association between alien grass cover and shrub cover. The possibility that small-scale soil disturbances could be an important contributing factor to alien grass invasion was supported by the positive correlation between disturbances and percentage alien grass cover. A positive correlation was found between the occurrence of indigenous grass and small-scale soil disturbances, while shrub cover tended to be less associated with animal activity. It is concluded that the correct management regime could effectively control the excessive invasion of alien grass species into the remnant renosterveld patches. Grazing (including all animal activity and small-scale soil disturbances) was the main facilitator of alien grass establishment - even dominating the prominent consequences of edge effects by facilitating alien grass establishment much deeper into the remnant patches. It could be assumed that a precise balance of low-pressure grazing and fire management should be established to enable the effective control of alien grass species while maintaining optimum biodiversity. Keywords: renosterveld, alien grass, grazing, fire, management, small-scale soil disturbances
AFRIKAANSE OPSOMMING: Met slegs 1.76% oorblywende Weskus Renosterveld wat bewaar word, is die beskerming en effektiewe bestuur van hierdie bedreigde plantegroei 'n prioriteit. Die vrugbare grond waarop renosterveld voorkom, het veroorsaak dat dit uitgeroei word om eerder die kultivering van ekonomies produktiewe landbou gewasse moontlik te maak. Dus het renosterveld verminder en gefragmenteer tot 'n kritieke punt. Hierdie ooblywende klein areas bedek met renosterveld, is blootgestel aan ekstensiewe invloede van die omliggende areas en die presiese afmetings vir 'n effektiewe grate renosterveld fragment vir bewarings doeleindes, moel nog vasgestel word. Die male van uitheemse gras spesie indringing in hierdie renosterveld fragmente is ondersoek deur die versameling van data deur die lyn-onderskep metode. Drie verskillende bestuursstelsels vir renosterveld is ondersoek om vas te stel wat die ergste graad van uitheemse gras indringing voorkom. Die studie het 'n 1) onlangs gebrande area, 2) 'n beweide area en 3) 'n kontrole area (wat nie gebrand of bewei is nie) ondersoek. Alle kleinskaalse grond-versteurings langs die lyne is ook aangeteken. Die resultate het aangetoon dat Briza spp., Bromus spp. en Avena fatua, as uitheemse grasse, die belangrikste indringers was en dus die grootste bedreiging inhou. Daar was 'n beduidende hoë variasie tussen die mate van uitheemse gras bedekking aangeteken in elk van die bestuurs-stelsels. Die beweide area het die hoogste graad van uitheemse gras indringing getoon, terwyl die kontrole area (in die afwesigheid van vuur en weidings aktiwiteite) die meeste weerstand teen uitheemse gras indringing getoon het. Die invloed van die omliggende omgewing was ook duidelik sigbaar in al drie die bestuurs-stelsels, maar was duidelik minder in die kontrole area waar die persentasie uitheemse gras indringing aansienlik verminder het na 'n afstand van vyftien meter in die renosterveld fragment in. 'n Swak positiewe korrelasie tussen die voorkoms van uitheemse grasse en inheemse gras spesies was aangeteken, asook bewyse van 'n swak negatiewe assosiasie tussen die uitheemse gras spesies en die inheemse bosse. Soos verwag, is daar bewyse gevind vir die teorie dat kleinskaalse grond-versteurings 'n belangrike fasiliterende faktor is vir uitheemse gras vestiging. Daar was 'n duidelike positiewe korrelasie tussen hierdie grond-versteurings en die persentasie uitheemse gras grondbedekking. Dieselfde positiewe assosiasie was gevind tussen die inheemse gras en hierdie kleinskaalse grond-versteurings, terwyl die inheemse bossie duidelik minder verbind was met die verskynsel. Die gevolgtrekking is gemaak dat 'n korrekte bestuurs-plan die indringing van uitheemse grasse effektief sal kan beheer. Dier aktiwiteite (insluitende beweiding, grawe van gate, mier en termiet neste ens.), en dus kleinskaalse grond-versteurings. was die grootste fasiliteerders van uitheemse gras indringing en vestiging binne hierdie renosterveld stukke. Dit oorheers selfs die aansienlike effek wat invloede van die omringende omgewing op hierdie areas het, deur die uitheemse gras indringing selfs dieper in die fragmente in aan te help. Daar kan dus aangeneem word dat 'n presiese balans tussen lae-intensiteit beweiding (en dus fauna aktiwiteit) en veld brande vasgestel moet word vir die effektiewe beheer van uitheemse gras spesies terwyl die optimum bio-diversiteit terselfde tyd gehandhaafword. Sleutelwoorde: renosterveld, uitheemse grasse, beweiding, vuur, veldbestuur, kleinskaalse grond-versteurings

Thesis (M.Sc. (Botany)) -- University of Limpopo, 2013
Traditional medicine plays a major role in the primary health care of many people residing in rural areas. People in these areas still consult traditional healers who utilise plants as medicine. Medicinal plants have come under increasing pressure due to a number of factors, which have resulted in the decline of certain species, extinction in others, and a general decrease in biodiversity of high use areas of South Africa, Blouberg Mountain included. To date there has been a lack of information on how traditional healers utilise the Blouberg Mountain with respect to amounts and species removed, or where the most important collecting sites are located. Thus, no conservation strategy exists for the Blouberg Mountain to ensure sustainable management of its natural resources. Furthermore, there is a perception amongst elders of this area that, as with indigenous knowledge around the world, the knowledge centered around Blouberg’s medicinal plants is declining, and little formal documentation of that knowledge has taken place. Consequently, this study investigated aspects related to medicinal plant use such as collection, patterns of collection, legislation, storage and packaging of medicinal plants by traditional healers around Blouberg Mountain. These were documented via a semi-structured questionnaire and a data collection sheet. Furthermore, traditional harvesting methods employed by traditional healers, and in situ conservation issues related to species removal from the mountain were investigated. Data was collected between September 2010 and September 2011. Sixteen villages in close proximity to the mountain, and 32 healers (two per village) were selected. In addition 16 consulting rooms were sampled (one per village) in order to gather information on the number of species collected from the mountain and stored in the consulting rooms. The 16 most used (indicated by village traditional healers) collection tracks, (one per village surrounding Blouberg Mountain), were travelled with traditional healers to record botanical and vernacular names of the medicinal plants, vegetation type, habitat, parts used, harvesting method, replacement value of plant species and perceived rarity of collected material. A Garmin GPS was used to record waypoints for the beginning and end of each track. Co-ordinates were logged automatically every 10 m. A map using Quantum GIS software to capture the position of the healers’ collection tracks, overlaid with topographical and vegetation information, and protected area information of the Blouberg Mountain, was generated. Geographic Information System software was used to geo-process the collection tracks of the healers with respect to where medicinal plants were collected relative to the various vegetation types. This gave information on vegetation types important to healers. The majority of traditional healers were females. Most of them had no formal education, with only a minority reaching secondary school. Due to their low level of literacy they tended to shy away from sources of written information, with the result that none of the questioned healers had any knowledge of the various national or provincial environmental legislations. The majority of them see between 15 and 20 patients per month. Most of the healers had more than 30 years of experience in traditional healing. The study found 64 plant species commonly used for medicinal purposes. Most of them were harvested for their roots and bark. According to the healers, Boophane disticha and Hypoxis hemerocallidea are declining in Blouberg Mountain, with Warburgia salutaris, endangered in South Africa, not perceived as rare or declining. However, a number of plant species recorded in the Red Data List as of least concern, or not threatened, are seen as rare by the healers. These include Clivia caulescens, Erythrina lysistemon, Lannea schweinfurthii and Maerua juncea. No exotic species were documented from the surveyed tracks. However, two naturalised exotics were collected from the mountain, namely Cassytha filiformis and Corchorus tridens. Cocculus hirsutus, a naturalised exotic and Abrus precatorius, an exotic species were found in one of the consulting rooms. Dichrostachys cinerea, Philenoptera violacea and Tarchonanthus camphoratus, which are indicators of bush encroachment, were identified on selected tracks. Tracks on which indicators of bush encroachment are present should be investigated more thoroughly to ascertain the extent and severity of such a threat. vii Investigations into healers’ collection tracks showed that the Soutpansberg Mountain Bushveld vegetation type is the most heavily utilised of the five vegetation types around Blouberg Mountain. This vegetation type is vulnerable to human population densities as most species were collected from it, therefore it should be conserved and managed if possible as it is targeted for plant species of medicinal value. The most travelled tracks were found in the Catha-Faurea Wooded Grassland community. Solutions to the problems of over harvesting of medicinal plants require local innovations and the full participation of traditional healers in resource management initiatives. The development of medicinal plant nurseries together with propagation of key species will be a crucial management tool, as this will reduce over harvesting of natural resources from the wild. In conclusion, it was found that although most species utilised around Blouberg Mountain are abundant and not threatened, healers are nevertheless concerned about dwindling medicinal plant supplies. They would welcome conservation initiatives and the use of GIS maps would be useful in prioritising conservation areas.

The study evaluated the extent and threat of bark harvesting of plant species for medicinal purposes in the Venda region and investigated possibilities of the sustainability of these practices. Approximately 30% of the woody plant species in Venda were found to have medicinal properties in their bark, but only about 12% of these species are commonly traded in muthi shops in the region. Fifty-eight medicinal plant species are commonly harvested for medicinal properties in their bark and found in muthi shops in the region. These 58 species were scored for the possible threat of bark harvesting to the species’ survival using 20 ecologically relevant plant population traits. The most vulnerable species were Adansonia digitata, Adenia spinosa, Albizia adianthifolia, Albizia versicolor, Brackenridgea zanguebarica, Croton megalobotrys, and Warburgia salutaris. Of these species Brackenridgea zanguebarica and Warburgia salutaris are amongst the ten most traded medicinal plant species in Venda region. Elaeodendron transvaalense and Brackenridgea zanguebarica, the two species investigated in detail in this study, were amongst the most commonly traded medicinal plant species in Venda region. Analysis of size class distributions showed that both species had growing and healthy populations, exhibiting J-shaped population curves, centroids left-skewed from the midpoint of the size class distribution, and a fine-grained status. However, size-class distributions in both species revealed certain classes that needed monitoring since they were negatively affected by bark harvesting. Adult individuals of B. zanguebarica showed a high degree of bark regeneration as a response to bark removal from medicine men. The crown health status of E. transvaalense was generally good although some individuals, contributing 9% of the sample, had dead crowns. A linear relationship was noticed between areas harvested and stem circumference, which is understandable considering the large surface area of harvestable bark on bigger individuals. Matrix modeling of E. transvaalense revealed that the vegetative stage should be targeted for management action. An assessment of the adequacy of the Brackenridgea Nature Reserve, an initiative aimed at protecting Brackenridgea zanguebarica, revealed that the reserve size is not enough for conservation of a viable population. The method flagged out potential growth habitat for B. zanguebarica around the current reserve, which could be incorporated to enlarge the conservation area, which could be incorporated to enlarge the conservation area. Four different scenarios were analysed on how best to conserve the species. Assuming a 50% reduction in human-related activities, such as cultivation, harvesting and livestock grazing, it is recommended that the reserve be enlarged from its current 110 ha to 366 ha to maintain a viable population into the future. Finally, the study recommended the adoption of an integrated approach to achieve sustainability of bark harvesting in the Venda region. Only by selecting best practices from both indigenous and conventional conservation techniques will the conservation of natural resources that are of important to local communities, be successful. An action plan that will involve the formation of an association by all stakeholders interested in the sustainable utilization of natural resources must be developed. The association must be governed by a constitution with a clear mission statement and the harvesting of natural resources should be done in line with a collection policy.
Thesis (PhD)--University of Pretoria, 2012.
Plant Science
unrestricted

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.

Bibliography: leaves 148-160.
The effects on birds of fine-scale differences in plant species assemblage and vegetation structure, and of two major disturbance factors (woody alien plant infestation and fire), were investigated in Mountain Fynbos at two sites in the southwestern Cape Province, South Africa. Three associated processes were also studied. These were the relative importance of three animal taxa as seed predators following fire, the extent to which an indigenous bird species ate alien Acacia cyclops fruits, and potentially dispersed its seeds, and the number of nectarivorous birds which visited an isolated nectar resource. Avian responses to fire in Mountain Fynbos varied according to season, locality and burning regime. Recently and cleanly burnt fynbos at a flat, low altitude, coastal site supported a distinctly non-fynbos avifauna, characterized by relatively large-bodied, ground-feeding, opportunistic species.

Thesis (M.Dev.) --University of Limpopo, 2012
The main aim or purpose of this study was to look at the ways and the strategies of minimizing\ mitigating the over-harvesting of indigenous medicinal plants in order to use them sustainably. The task of identifying and assessing challenges facing local communities in utilizing and sustaining indigenous medicinal plants in Thengwe village and their implications on environmental conservation and management of natural resources was done during the pilot survey. The environmental field survey was conducted after gaining permission to enter into the identified study areas including the Mutavhatsindi Nature Reserve. The result revealed that most of the indigenous medicinal plants are used for healing, religious, economical and for protection purposes. Most of the indigenous medicinal plants in the study area are depleted and many of them are facing extinction. The study was qualitative in design. Semi-structured interviews and a questionnaire were used. The questionnaire had both open-ended and closed questions. The study area was Thengwe Village in the Mutale Municipality. The existence of medicinal plants is threatened by people `s perceptions and attitudes towards them. For some indigenous medicinal plants, depletion is at a high rate due to over-harvesting and because the plants when traded by herbalists they have a premium price attached to them. Interestingly, perhaps surprisingly, the majority of young people hold negative attitudes towards the indigenous medicinal plants due to poor knowledge of the value of indigenous medicinal plants, in contrast to the elders who appreciate their role and consider them as part of their culture, economy and religion. One of the findings is that medicinal plants were found to be important to the community members as the source of income and creation of jobs for the medicinal collectors who sell the species to traditional healers. For the reason of preserving indigenous medicinal plants and others as the environmental resources, this study recommends that there should be strong intergovernmental relationships between the National, Provincial and Local governments in order to prevent over-harvesting of the medicinal plants. The indigenous medicinal plants are equally important to biodiversity students and researchers who want to study and research indigenous medicinal plants which play an important role in the improvement of the livelihoods of community members. Furthermore, education campaigns within the communities and school learners are recommended to encourage the prevention, sustainability and utilization of the indigenous medicinal plants. Additionally, the legal authorities should be empowered to prosecute all people who may be found illegally in possession of indigenous medicinal plants, as well as endangered and protected species. Heavy fines and charges should be imposed on such culprits. Of importance is the fact that the results and recommendations of this study may facilitate the teaching of environmental education and management of natural resources as well as boost the local economy of the Vhembe district Municipality by showing that medicinal plants in the area can be seen as a viable tourist attraction.

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: I evaluated the impact of Prosopis invasion and clearing on ecological structure, function and agricultural productivity in heavily grazed Nama Karoo rangeland on two sheep farms near the town of Beaufort West in the Western Cape Province of South Africa. My aims were to (1) determine the effects of invasion and clearing on rangeland vegetation composition, diversity (alien and indigenous species richness) and structure (alien and indigenous species cover), soil vegetation cover (plant canopy and basal cover) and agricultural productivity (grazing capacity), (2) describe the vegetation processes that underlay the invasion and clearing impacts and (3) evaluate the success of clearing in facilitating unaided restoration of ecological structure, function and agricultural productivity in formerly invaded rangeland. I hypothesised that invasion would significantly change rangeland vegetation composition and structure, leading to greater alien species richness and cover and lower indigenous species richness and cover while clearing would lead to lower alien species diversity and cover and greater indigenous species richness and cover. In addition I hypothesized that invasion would reduce rangeland plant canopy and basal cover and grazing capacity while clearing would substantially increase them. Finally I predicted that vegetation composition, alien and indigenous species cover and richness, plant canopy and basal cover and grazing capacity would revert to pre-invasion status and levels within four to six years of clearing. My results suggest that in heavily grazed Nama Karoo rangeland Prosopis invasion (~15 percent canopy cover) and clearing can significantly change rangeland vegetation composition, with invasion leading to greater alien species cover and lower indigenous species richness, while clearing leads to lower alien species richness and cover and greater indigenous species richness and cover. However invasion seems to have no effect on alien species richness and overall indigenous species cover. Clearing appears to facilitate the spontaneous restoration of alien species cover and indigenous species richness within four to six years but not species composition, alien species richness and indigenous species cover. In addition my results also indicate that Prosopis invasion can lower rangeland plant canopy and basal cover and grazing capacity while clearing, even under heavy grazing, can substantially raise them. Clearing however does not seem to facilitate the restoration of rangeland plant canopy and basal cover and grazing capacity to pre-invasion levels within four to six years after clearing.
AFRIKAANSE OPSOMMING: Ek het die impak van Prosopis indringing en verwydering van indringers op ekologiese struktuur, funksie en landbou produktiwiteit in ‘n swaar beweide Nama Karoo gebied op twee skaapplase naby Beaufort-Wes in die Wes-Kaap provinsie van Suid-Afrika geëvalueer. My doelwitte was om (1) te bepaal wat die gevolge van die indringing en verwydering van indringers op die natuurlike plantegroei samestelling, diversiteit (uitheemse en inheemse spesiesrykheid) en struktuur (uitheemse en inheemse spesies bedekking) sal wees, sowel as die effek op plantegroei bedekking (kroon en basalebedekking) en landbou produktiwiteit (weidingkapasiteit), (2) die plantegroei prosesse te beskryf wat onderliggend deur die impakte van indringing en verwydering van indringers veroorsaak word, en (3) die sukses van die verwydering van indringers te evalueer deur die fasilitering van blote restorasie van ekologiese struktuur en funksie en landbou produktiwiteit in voorheen ingedringde gebiede. My hipotese is dat indringing ‘n aansienlike verandering in natuurlike plantegroeisamestelling en struktuur sal veroorsaak, wat sal lei tot groter uitheemse spesiesrykheid en bedekking met minder inheemse spesiesrykheid en bedekking, terwyl die verwydering van indringers sou lei tot minder uitheemse spesie diversiteit en bedekking met 'n groter inheemse spesiesrykheid en bedekking. Verder vermoed ek dat indringing die natuurlike kroon- en basalebedekking en weidingkapasiteit sal verminder, terwyl die verwydering van indringers dit aansienlik sal verhoog. Ten slotte voorspel ek dat plantegroei samestelling, uitheemse en inheemse spesiesbedekking en -rykheid, kroon- en basalebedekking en weidingkapasiteit sou terugkeer na voor-indringing status en vlakke binne vier tot ses jaar na die verwydering van indringers. My resultate daarop dat die indringing van Prosopis (~ 15 persent kroonbedekking) en die verwydering van indringers in swaar beweide Nama Karoo gebiede ‘n aansienlike verandering in die gebied se natuurlike plantegroei samestelling toon, waar indringing gelei het tot groter uitheemse spesiesbedekking en minder inheemse spesiesrykheid, terwyl die verwydering van indringers lei tot minder uitheemse spesiesrykheid en groter inheemse spesiesrykheid en - bedekking. Dit lyk egter of indringing geen effek op uitheemse spesiesrykheid en algehele inheemse spesiesbedekking het nie. Die verwydering van indringers blyk om die spontane herstel van indringerbedekking en inheemse spesiesrykheid binne vier tot ses jaar te fasiliteer, maar nie spesiesamestelling, uitheemse spesiesrykheid of inheemse spesiesbedekking nie. Benewens dui my resultate ook aan dat Prosopis indringing die natuurlike kroon- en basalebedekking sowel as weidingskapasiteit verlaag, terwyl die verwydering van indringers, selfs onder swaar beweiding, die bedekking aansienlik kan verhoog. Verwydering van indringers lyk egter nie asof dit die herstel van die gebied se natuurlike kroon- en basalebedekking en weidingkapasiteit na voor-indringing vlakke toe kan fasiliteer binne vier tot ses jaar na die verwydering van indringers nie.

The fire-prone mountain fynbos of the southwestern Cape Province of South Africa has been severely invaded by introduced trees and shrubs. These invasions have transformed fynbos shrublands to dense thickets of trees and shrubs in many parts of the region, thus disrupting various natural ecosystem processes. The ecology of invasions by species of Pinus and Hakea (the most successful genera) was studied using a series of natural experiments in conjunction with autecological studies. The study was divided into main four parts: (i) case studies to elucidate major patterns and processes of invasion; (ii) studies of the life history and population ecology of selected invaders; (iii) studies of the determinants of invasibility; and (iv) assessments of the consequences of invasion and of control programmes. Bibliography: pages 235-272.

Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005.
Benthic macroinvertebrates (sampled using South African Scoring System, SASS5) and adult male Odonata (sampled with close-focus binoculars) were recorded on two streams and a river of Soutpansberg, with the aim of determining the effect of invasion and removal of alien riparian vegetation on their assemblages. A secondary aim was to establish the importance of dragonflies as indicators of degree of disturbance in rivers. Forty two aquatic macroinvertebrate families and 33 adult Odonata species were recorded at a total of 71 sampling units. Three distinct riparian vegetation types were selected (natural, alien and cleared). Cleared vegetation refers to clearing of invasive alien trees, allowing regrowth of natural vegetation. Natural and cleared vegetation supported more benthic macroinvertebrate families compared to alien vegetation. Certain families that were lost to alien vegetation were recorded from natural vegetation. The highest SASS5 score was recorded from natural vegetation, followed by cleared vegetation, and the lowest was from alien vegetation. The highest number of adult Odonata was recorded at cleared vegetation, with alien and natural vegetation supporting the least number of Odonata species. Vegetation type, stream flow and microhabitats were statistically identified as the most influential variables for benthic macroinvertebrate assemblages. For adult Odonata assemblages, vegetation type, shade and temperature were the most important environmental variables. Species assemblages of adult Odonata can be used as indicators of environmental condition of rivers. The clearing of alien riparian vegetation clearly benefits the indigenous benthic macroinvertebrates as conditions are restored to their natural state. It also benefits dragonfly species richness, but if natural succession proceeds to a shaded tree canopy, the effect becomes similar to that of habitat shaded by alien vegetation. The impact of alien vegetation is to reduce sun-loving invertebrate species, especially dragonflies, with lesser impact on shade-loving species.

The Southern Ground Hornbill (SGH) (Bucorvus leadbeateri) has recently been listed globally by the IUCN Red list as Endangered or Critically Endangered. In South Africa, the declining population of the SGH has led it to be listed nationally as Vulnerable and falls under the “Protected Species” legislation. Research into the habitat preferences and identification of suitable reintroduction areas have been few since the initiation of reintroduction attempts, therefore resulting in mixed outcomes of previously-reintroduced SGH. The aim of this study was to identify and verify optimal reintroduction sites for the SGH, in the Musina area in the Limpopo Province. Five main objectives were determined, namely: to identify optimal reintroduction areas; to develop a habitat profile of the designated area; to determine the availability of prey items; to determine the availability of large trees needed for nesting and roosting; to evaluate pre-release sites by involving a number of stakeholders. Three study sites were selected on the farm Greyghost Safaris (Ludwigslust), each made up of a different plant community. Sampling was carried out a total of four times during the year: one sampling bout in each season. A niche-based modelling technique was used to describe the suitability of a particular habitat (“ecological space”) then used to project it onto another geographical space. Floristic and faunal surveys were conducted to determine the species composition of prey items and composition and frequency of the herbaceous and woody layer. High-resolution, natural-colour aerial imagery was used in order to determine the availability of trees for nesting and roosting. Pre-release site evaluations and stakeholder engagements were conducted by means of interviews with landowners on and around the study sites. The Limpopo River Valley and across to the KNP on the eastern border of the Limpopo Province, is suitable re-introduction sites for the SGH. This study site provided a good opportunity to explore what an optimal site for reintroduction should resemble.
Thesis (MSc (Zoology))--North-West University, Potchefstroom Campus, 2012.

In most rural areas, reliance on traditional medicine and food is high and this is attributed to both economic and cultural factors. The edible stink-bug (Encosternum delegorgueiSpinola), local name “thongolifha” is consumed by the Venda tribe in Limpopo Province of South Africa. Thongolifha is important to the Venda tribe in terms of culture, nutrition and economical value. They eat it raw or cooked with porridge or as a snack. The edible stink-bug is sold at the Thoyandou open market and provides valuable income for the harvesters. Many insects have been reported to contain good source of proteins minerals and vitamins. In terms of medicinal value, insects have also been used in folk medicine in the past by various cultures to treat many ailments such as stroke, asthma, cold, etc. Some insects are also known to sequester compounds from their host plant and use them for its defensive mechanism. The host plant for thongolifha was identified as Dodonaea viscosa Jacq. var. angustifolia which has been reported to have antibacterial activity. The aim of this study was to investigate the possible interaction between the thongolifha and its host plant Dodonaea viscosa. Since thongolifha is so important to the Venda tribe and its nutritional value was never analysed before it was also relevant to determine its nutritional composition. Nutritional components of thongolifha such as the proteins, fats, amino acids and carbohydrates contents were detected by using standardized methods. Thongolifha contained 35.2% protein, 50.6% fat and 7.63 g/100 g carbohydrate with an energy content of 2599 kJ/100 g. These results compare well to nutritional values of other edible insects such as termites (41.8% protein and 44.3% fat) and wasps (31% protein and 62% fat).The mopane worm has higher protein content (63.5%) and a lower fat content of (18%). Mineral content of thongolifha (1.2 g/100 g) was found to be at a comparable level to other bugs such as the Acantocepphala declivis (1.0 g/100g). Analysis of essential amino acids varied from 0.82 mg/100 g (threonine) and 1.32 mg/100 g (valine). The nutritional composition of thongolifha is acceptable and thongolifha is not just a traditional delicacy but also contributes as a diet supplement of the Venda tribe. Between 680 and 3400 of thongolifha will however have to be consumed to supply the daily nutritional needs for the essential amino acids phenylalanine and methionine. Analysis for antibacterial activity of thongolifha was carried out after extracting with solvents of varying polarities, separation by thin layer chromatography (TLC) and bioautography against four nosocomial bacteria; Gram-negative; Escherichia coli and Pseudomonas aeruginosa; Gram positive; Staphylococcus aureus and Enterococcus faecalis. Bioautography results of the thongolifha extracts revealed some activity against S. aureus and E. faecalis. Evaluation of the minimal inhibitory concentration (MIC) by using a serial dilution microplate method indicated low antibacterial activity (MIC > 2.5 mg/ml). Thongolifha therefore does not contain antibacterial compounds but there may be present in a low concentration or the serial dilution microplate method does not work well with insects extracts. Some insects contain peptides as antibacterial compounds. Spraying thongolifha extracts chromatograms with several spraying reagents indicated that these antibacterial compounds were not peptides Methanol crude leaf extracts of D. viscosa was reported in the literature to have antibacterial activity against S. aureus however the results were obtained by using the agar diffusion method which does not provide convincing quantitative results. In our study we extracted components from D. viscosa using solvents of varied polarities to evaluate its antibacterial and antioxidant activities. Dichloromethane and acetone extracted more compounds with good antibacterial activity against S. aureus, E. faecalis, E. coli and P. aeruginosa. The average MIC values varied from 0.04 to 0.28 mg/ml, indicating excellent to good antibacterial activity. The antioxidant activity using the DPPH Spectrophotometric assay gave the EC50 of the extracts of 212 ± 4 to 469 ± 9 µg/ml. As expected, the more polar crude extracts, ethyl acetate and acetone demonstrated higher activity compared to other extracts. This was supported by the TLC qualitative assay showing more yellow bands in these extract on TLC chromatograms after spraying with 0.2% DPPH in methanol. To determine whether thongolifha has sequestered compounds from the host plant, D. viscosa, a serial exhaustive extraction was performed in order to extract components from the crude extracts of both insect and the host plant by using various solvents and separating the extracts on TLC plates by using various eluant systems. After the TLC chromatograms were sprayed with vanillin-sulphuric acid to reveal separated components, there were few similarities of components from both insect and host plant. This could mean that either a sequestered plant compounds are present in low quantities in the insect extract, that insect may have metabolized the sequestered compounds or alternatively that the insect might not have sequestered the compounds from the host plant at all. It should be kept in mind that the stink-bugs feed by sucking sap from the host plant. By using bioassay-guided fractionation based mainly on silica gel chromatography, four compounds (5-hydroxy-3,74’-trimethoxyflavone (1); 5,7-dihydroxy-3,6,4’-trimethoxyflavone (2); 5,7,4’-trihydroxy-3,6-dimethoxyflavone (3); and 4’-O-methylkaempferol (4) where isolated from dichloromethane fraction of a crude D. viscosa leaf extract, acetone crude leaf extract yielded only one compound, Kaempferol (5). Compounds 1, 2, 3 and 5 where previously isolated from D. viscosa whereas compound 4 was isolated for the first time from D. viscosa. Compounds 4 is not a novel compound because it was previously isolated from other plants species such as the Lens culinaris. Compounds 3, 4 and 5 have good antibacterial activity against E. coli and E. faecalisat MIC values of 15.63 µg/ml and 31.25 µg/ml respectively. In addition, the DPPH quantitative assay has demonstrated that Compounds 4 and 5 have strong antioxidant activities (EC50 = 35.1 ± 0.85 and 75.5 ± 1.76 µM respectively) but lower than L-ascorbic acid (EC50 = 13.5 ± 0.28 µM) used as a standard antioxidant agent. The antibacterial and antioxidant activity of most of the isolated compounds were not known previously. Investigation of structure antibacterial-activity relationship in the isolated compounds did not yield a clear correlation. When investigating the possible interaction between the insect and the host plant, bioautography assay has shown compounds with antibacterial activity against S. aureus (Rf 0.79) E. faecalis (Rf 0.66) when separated with CEF eluent system. Some of the isolated compounds from D. viscosa leaf extracts had an Rf of 0.79 (5, 7-dihydroxy-3, 6, 4’-trimethoxyflavone) and Rf 0.61 (5, 7, 4’-trimethoxxyflavone) when separated with CEF eluent system. These findings indicate that thongolifha may have sequestered the two compounds from D. viscosa leaves, but this possibility has to be confirmed. This study has indicated that thongolifha is good source of protein, vitamins, minerals and amino acids; however we have not found evidence of significant antibacterial activity of thongolifha. If fresh material of thongolifha can be analysed in future work the probability of finding medicinal properties may be greater. On the other hand, D.viscosa. crude leaf extracts have demonstrated strong antibacterial and antioxidant activities; although isolated compounds have shown moderate level of activities. Because practically all antibacterial compounds based on bioautography have been isolated, it is clear that in the crude dichloromethane extract some synergism must have taken place because the antibacterial activity on a mass basis was nearly as good as the isolated compound without removing >90% of non active compounds.
Thesis (PhD (Paraclinical Science))--University of Pretoria, 2006.
Paraclinical Sciences
PhD
unrestricted

MESMEG
Department of Ecology and Resource Management
Invasive alien plants refer to plant species that show a tendency to escape from human control, go beyond the intended physical boundaries and cause environmental damage. The issue of letting the Invasive alien plant species grow and spread, with no attempts made to control the spread of the species beyond the limits of plantations, is not sustainable. All the attempted methods that the Department of Environmental Affairs used seemed to have failed in yielding the expected results. The main objective of the study was to determine the Wolkberg Working for Water programme’s level of success in terms of clearing invasive alien plant species. Wolkberg Project was used as a case study as it is one of the Working for Water Programme. The data were collected using random sampling methods on the worked areas, where work is in progress and those where no work has been done. Primary data were collected from land owners through field observations and questionnaires from the participants whilst secondary data were collected from the Department of Environmental Affairs. The study adopted a mixed methods approach which is both quantitative and qualitative. The data were analyzed using Statistical Package for the Social Sciences (SPSS) package. The research determined the level of success in terms of clearing invasive alien plant species, employment opportunities, tools/materials that have been used to clear the plants and the advice on the possible strategies that can be employed in the invasive alien plant species management. It was found out that the Invasive alien plant species require constant maintenance in order for them to be controlled. The Wolkberg project is mainly dominated by male workers compared to females. Each team comprised 3% underage workers. The study recommends that the project should make sure that the follow-ups are done at the correct time and stage. Looking at the statistics of males and females, the study revealed that transformation is not adhered to in this project.
NRF

MSc (Botany)
Department of Botany
Invasive alien plants (IAPs) are non-native species that have spread beyond the introduction site; become abundant to an extent that they serve as agents of change that also threaten native biological diversity (Garcia-Berthou, 2007). IAPs have medicinal applications for the treatment of various aliments in humans (Jäger et al., 1996). In this study, an ethnomedicinal survey was conducted on medicinal uses of invasive alien plant species in order to identify and investigate the various disease treatment methods employed by Bapedi traditional health practitioners within Capricorn District. Six traditional health practitioners were randomly selected, via the snowball method from each of the five local municipalities namely: Aganang, Blouberg, Lepelle-Nkupi, Molomole and Polokwane. The whole survey included 30 traditional health practitioners. A semi structured questionnaire was administered to document information about the medicinal uses of IAPs from participants. The collected data from the questionnaire was captured in Microsoft Excel 2010 and analyzed using descriptive statistics. The study recorded 22 IAPs belonging to 14 plant families. Records or data collected show invasive alien plants species to have been used for treatment of different alignments amongst Bapedi traditional health practitioners. Plant families with the most recorded species include: Solanaceae and Myrtaceae with 18.2% for both of them. The plant parts most frequently used in descending order were as follows: roots vii (40%), followed by the leaves (39%), fruits (7%), thorns (6%), bark (4%), seeds (2%) and lastly stems (2%). Decoction was recorded as the most dominant method used during medicinal preparations (n = 176) and flu was recorded as the most treated ailment amongst traditional health practitioners (n = 29). Apart from clearing IAPs as part of management strategy by South African government, there are other alternative innovative ways that can be employed to ensure that the number of IAPs introduced does not exceed beyond measure.This could be achieved by encouraging local people to use them as either medicinal sources or by incorporating them into any other local ethnobotanical use. The new innovative ways (such as traditional health practitioners utilizing the IAPs instead of endangered plants or indigenous plants species) can bring in some form of relief to the already declining indigenous species populations. Research scholars from different research institutes and higher education research centres can regard IAPs used medicinally as source of new pharmaceutical leads to create new medications. With such attention turned to alien invasive species, their survival as well as their spread will be kept on check at the same time creating a control measure to their spread with little effort. Further laboratory-based studies are needed to determine efficiency and safety of the IAPs used by traditional health practitioners in this study.
NRF

MSc (Botanty)
Department of Botany
Background: Problem plants and alien invasive weed species are part of today‟s ecological transformation. Ethnobotanical literature on ecological prominence and ethical values of problem alien weeds is scant and should be documented to avoid loss of valuable species. Aim: The study was aimed at documenting problem weeds and alien invasive plant species considered to be beneficial in deep rural communities. Materials and method: Purposeful triangulation research methods were used to ensure the proper gathering of both qualitative and quantitative data sets. Results and conclusion: Some problem weeds and alien invasive plant species are being utilized by local people to maintain their livelihood. A total of 78 plant species from 33 families were recorded. These plant species belonged to diverse growth habits, namely: climbers, herbaceous, succulents, shrubs, trees as well as creepers. Recorded problem weeds and alien invasive plant species were contributing towards ecological, medicinal and social values. These included being utilized as a source of food (14), fruits (4), medicinal (31), ornamentals (7), firewood (3), social (2) and multiple purposes (17). The main utilized families were Asteraceae (14.1%) and Solanaceae (14.1%). These families were mostly utilized for the purpose of medicinal and food. Plant species that were widely used are as follows: Achyrathes aspera L., Agave sisalana L., Amaranthus spinosus L., Anredera cordifolia L., Canna indica L., Centella asiatica L., Chenopodium album L., Chenopodium ambrosioides L. and Chromolaena odorata (L.) R. M. King and H. Rob. The dominant category for problem weeds and alien invasive plant species was 1b (44%) followed by weeds (35%), category 2 (9%), invaders (5%), category 3 (4%) and 1% for both category 1, 1a as well as X3. The results revealed that the legislative listing of plant species as problem weeds and alien invasive species was based on single knowledge basis system, rather than on multi-dimensional knowledge systems. Therefore, this study recommended that for judgment to be considered in decision-making, it should be based on species-specificity as well as multi-dimensional-knowledge basis. The reconciliation of inherent grapples among scientific and indigenous knowledge systems could possibly be underpinned by equal legislative consideration for the aforementioned knowledge systems especially in the establishment and implementation of environmental regulations. This could also aid with the provision to support transformation in South Africa and worldwide.

MENVSC
Department of Ecology and Resource Management
Certain communities in Sekhukhune area are known to be practicing geophagia. Existing standard questionnaires as adopted to generate data on human geophagia included aspects on demography, socio-economics, cultural, ecological, physico-chemical aspects, indigenous knowledge and health effects of geophagic consumers. These data were gathered through distribution of questionnaires to 200 geophagic participants, of which 135 were from Ga-Nchabeleng Village and 65 from Mphanama Village. Both the Villages were based in the rural settlements in Sekhukhune area. In this study the behaviour of geophagic individuals was investigated and cytotoxicity of plant remains consumed in geophagic soils was evaluated for any toxicity. A total of 17 different geophagic sites were identified. Six geophagic sites each were from Ga-Nchabeleng Village and six from Mphanama Village. Five other sites were selected from sites where geophagia was not practiced and were recorded as the control sites. All the 17 soil samples were analysed using Munsell Soil Color charts for soil colour classification. Samples of plant remains were collected from the same geophagic sites where soil samples were collected. Due to similar plants and vegetation type from 17 different geophagic sites, a composite study was adopted. Geophagic consumers in Ga-Nchabeleng Village identified four plant species of plant remains consumed in the soil in the area and Mphanama village identified five species different from Ga-Nchabeleng plants. Samples of plant remains were grouped according to comparable features or characteristics. Sample 1 of plant remains was composed mainly of grasses; Cynodon dactylon, Aristida congesta and Eragrostis rigidior whereas sample 2 of plant remains was composed of Acacia plant; Vachellia tortilis. The two samples of plant remains were collected from Ga-Nchabeleng Village. Sample 3 of plant remains was composed of creeping, perennial weed herbs; Alternanthera pungens Kunth and Alternanthera lorentzii. Sample 4 of plant remains was composed of prominent woody plants; Combretum apiculutum, Kirkia wilmsii and Boscia albitrunca. Samples of plant remains 3 and 4 were collected from Mphanama Village study sites. Sample 5 of plant remains was the control site and composed mainly of Acacia plants; Vachellia nilotica, Acacia vii mearnsii and Vachellia tortilis and were collected from sites not used for geophagic practices. The plant remains parts mostly consumed were roots (50%) in Ga-Nchabeleng, whereas in Mphanama Village they were stems (54.5%) and the control site had leaves at 62.5%. The five samples of plant remains were recovered using physical separation method. The plant remains were washed and dried. Retch Muhle grinding machine was used to ground the samples. Methanol was used in the extraction of all the samples of plant remains. The result from the administration of the questionnaire revealed that geophagia in this area was practiced by both male and female Sepedi-speaking individuals. Ga-Nchabeleng Village had more female geophagic participants, whereas Mphanama Village had more males who have almost undergone secondary school. However, in general for the study there were more female geophagic consumers. Geophagic consumers ingest soil known locally as Mobu, Letsopa or Leraga collected mostly from the riverbanks, mountains/hills and valleys with only a few that indicated termite mounds. Geophagic consumers in the study used colour, among other things, to describe their soil of preference. The study consisted of 200 participants of whom 172 represented the geophagic group and 28 were the control group, aged between 18-65 years analysed using chi-square crosstabulation. There was no significant difference in human health effects associated with geophagia between the geophagic group and the control group. There was also no association established between soil consumption and other non-food substances between geophagic group and control group. Chi-square (χ2) analyses revealed a significant association of gender with geophagic habits (p<0.05), while there was no association of age, educational level, income source and marital status (p>0.05) with geophagic habits. Findings of the survey when two villages are combined revealed that more females (75.60%) practice geophagia compared to males (24.40%). The respondents from both study sites preferred digging technique when collecting the soil. It was established that craving was mainly the reason behind the practice in the study area. Hygiene and environmental conditions were not considered when mining viii geophagic soil as the majority of them used dirty utensils, hands for collection and non-sterile bags and tins for packaging. Some of the soils were collected close to waste dumping sites as seen whilst visiting geophagic mining sites. Majority of the consumers had little or no knowledge that the soil could be harmful or if it contained any contaminants. This sample of interviewees provided valuable information on human geophagic practices in Sekhukhune area. It became clear that this practice was entrenched in the cultural behaviour of people in the area and a need for educating them on health related aspects. The cytotoxicity of methanolic extracts of plant remains on HEK-293T cell line was evaluated using MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay for cell viability. The 50% cytotoxic concentration (CC50) was defined as the compound’s concentration (500, 250, 125, 62.5, 31.25, 15.625 and 7.8125 μg/ml) required for the reduction of cell viability by 50%. Evaluation of cell viability showed the methanolic extracts of plant remains on HEK-293T cell line ranged in the order of plant remains extract=3>1>4>2>5 according to their cytotoxicity activities. Plant remains extract 3 from Mphanama Village showed high cytotoxicity with a CC50 of 13.75 μg/ml, followed by plant remains extract 1 at 16.68 μg/ml, plant remains extract 4 at 58.95 μg/ml, plant remains extract 2 at 92.75 μg/ml and the control at 251.4 μg/ml, respectively. In the study only the methanolic extract was investigated for cytotoxicity using HEK-293T cell line. Further research need to be conducted on the individual plants of each plant remains to be able to have conclusive results on the cytotoxicity profile. This will indicate which specific plant part is toxic or whether they exhibit a higher CC50 only when in combination.

MSc (Microbiology)
Department of Microbiology
Background: The medicinal value of plants lies in some chemical substances that produce a definite physiological action in the human body. The secondary metabolites help the plants to survive hash conditions and could be used by humans as supplements of their health, as foods additives or for medicinal purposes. This bioactive compounds are not always beneficial to human beings, and some of this plants bioactive compounds can be toxic or genotoxic to human cells. This study used several methods to evaluate of phytochemical constituents and mutagenic properties of Coccinia rehmanni and Jatropha zeyheri plant extracts. Methodology: Methanol was used for extraction of the bioactive compounds from the two selected plants, filtered with Whatman filter paper and evaporated with rotary evaporator. The extracts were fractionated using open column chromatography. Chemical and TLC methods were used to determine phytochemicals of the study plants extracts and fractions. The plants extracts and fractions were tested against Vero cell lines in order to evaluate cytotoxicity and genotoxicity of the plants. NucRed and LTR Hoechst 33342 dyes were used for cytotoxicity and genotoxicity respectively. For the evaluation of cytotoxicity and genotoxicity Quantification of live and dead cells for the screening assay was performed using the ImageXpress Micro XLS Widefield Microscope and acquired images analyses using the MetaXpress software and Multi-Wavelength Cell Scoring Application Module. Antimutagenicity of plants extracts was observed using PARP universal colorimetric assay kit. Acquired data was transferred to an EXCEL spreadsheet and data was analyzed. Results and discussion: C. rehmanni (12.03%) yielded more extract than J. Zeyheri (8.20%). the two plants had different compound composition and were in different stages of maturity. The study revealed the domination of Terpenoids, Cardiac glycosides, Phenolic and tannis. With an exception of two fraction fractions all the fractions was found to be toxic to an extent were genotoxicity of such fraction could not be concluded. The reason for such extreme toxicity could be due to the influence of the retained alcohol during rotary evaporation. xvi | P a g e Conclusion: this study provides and add to existing knowledge on the phytochemicals mutagenicity and anti-mutagenicity of C. rehmanni and J. Zeyheri medicinal plants. The study serves as scientific proof that extensive use of this plant in traditional medicine for treatment of various ailments may lead to some irreversible damages.
NRF

MENVSC
Department of Hydrology and Water Resources
Sewage sludge (biosolids) from wastewater treatment plants (WWTPs) has been widely used as a soil improver in Europe, United States of America and some developing countries including South Africa. It has its benefits for farmers as a good source of organic matter and minerals, however, sludge after treatment still contains pathogenic organisms, heavy metals and persistent organic pollutants (POPs). The POP and heavy metal contaminants that accumulate in sludge may transfer through the food chain and cause adverse effects on human beings. In this study, a field experiment was carried out on farmland fertilized with sewage sludge from a wastewater treatment plant (WWTP) that vasically receives domestic wastewater and storm water. Vegetable spinach (Spinacia oleracea) was used for this study and was planted on a farmland under controlled conditions. Ten ridges each of dimensions 20 m × 0.3 m was made and dry sludge weights of 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 kg were applied as manure on each of the ridges, respectively. Representative samples of sludge and soil were taken for analysis of heavy metals and POPs. At maturity, in twelve weeks, the root and leave samples of the vegetable were taken from all the ridges including the control. The soil, sludge, and vegetable samples were analyzed for total heavy metal content (Cd, Cr, Cu, Ni, Pb, Co, Zn, Al, Fe, Mn), speciated heavy metal content and POP (PAH, PCB). Soil and sludge samples were also analyzed for total organic content, pH, cation exchange capacity (CEC), conductivity and alkalinity. The analysis for total heavy metals and speciated heavy metal content was carried out using inductively coupled plasma optical emission spectrophotometer (ICP-OES), and CEC analysis was carried out using atomic absorption spectrophotometer (AAS). A two-dimensional gas chromatograph with time of flight mass spectrometry detector (GC X GC TOFMS) was used for POP measurements. pH measurement was made using a pH meter and conductivity measurement using a conductivity meter. Alkalinity and total organic content analysis was performed using titrimetric apparatus. The highest total heavy metal concentration of 378.9 mg / kg was recorded in Fe metal in soil and Leaf sample while the lowest total metal concentration of 0.0003 mg / kg was in Cu metal in root sample. The highest heavy metal concentration of 1002 mg / kg in speciated forms was in Mn metal in F1 fraction and the lowest of 0.0004 mg / kg was in Cd metal in F5 fraction. PAHs were only found in soil samples and their concentrations ranged from 2.53 mg / kg to 146.5 mg / kg. There were no PCB detected in all the samples analysed. The results indicated that the trace metals concentrations found in the exchangeable fraction were higher than those observed in any of the preceding extractions except in the case of Cd, Cr, Fe and Pb where Fe-Mn oxide and organic matter fractions predominated and were closely followed by exchangeable fraction.

MSc (Botany)
Department of Botany
Since time immemorial plants have traditionally been used for various purposes in many parts of the world including Vhembe district, Limpopo province of South Africa. The use of C. abbreviata plants at Matsa village of Vhembe district also contributes significantly to the livelihood of the community. However, little work has been made in the past to properly document and promote the knowledge. The purpose of the present study was to record and analyse the ethnobotanical knowledge of C. abbreviata within the people of Matsa village around Nzhelele in Vhembe district. Semi-structured questionnaires were administered on 50 informants from different households selected randomly to gather data regarding the local name of C. abbreviata, the uses and its availability. Significantly higher number of medicinal use was reported by elderly people including both men and women as compared to middle-aged, younger people. Other use categories included firewood, furniture and joinery production and shade for people in the area. Awareness on the importance of the species should therefore be created amongst the people, especially the young ones. Understanding the ethnobotanical knowledge of indigenous species within an area is crucial towards development of its management plan.
NRF

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.

PhD (Zoology)
Department of Zoology
An ever growing human population and accelerating land use change is associated with the loss of species and their ecosystem services. Agricultural intensification has led to a worldwide threat of extinction to about one quarter of all bat species, despite the valuable ecosystem service of pest control provided by bats. The decline in bat populations is mainly attributed to the loss or fragmentation of habitats, roost sites and feeding opportunities related to agricultural intensification and land use change. Therefore, proactive management of bat communities in agricultural landscapes is essential. South Africa is the world’s largest producer of macadamias and the industry continues to grow. This study gains insight into the habitat use and foraging behaviour of insectivorous bat species on a temporal and spatial scale, in and around macadamia orchards in order to advise management strategies on how to increase bat activity and, possibly, pest control. It also focuses on the preferences of artificial roost sites used by insectivorous bats in macadamia orchards. The diet of insectivorous bat species is especially difficult to study and the least invasive tool to gain information is the study of bat faecal pellets. In order to provide evidence for the consumption of pest insect species by bats and thus incentive to farmers for a more integrated pest management approach (IPM), this study explored molecular approach to insectivorous bat diet analyses using fragment analysis of bat faecal pellets with fluorescent-labelled species-specific primers (designed for the CO I gene). This study was conducted in the subtropical fruit growing area of Levubu, Limpopo province, South Africa between the towns Thohoyandou (22°59'03.7 S, 30°27'12.8 E) and Makhado/Louis Trichardt (23°03'03.6 S, 29°55'12.7 E). Levubu also accounts for the second highest production of macadamia in South Africa. An introduction to the order Chiroptera and into the relevance of insectivorous bat species to agriculture as well as the importance of a more integrated pest management approach (IPM) focusing on bats is provided in Chapter One. Bats were acoustically monitored and light traps were used to catch arthropods during one annual cycle. I sampled five macadamia orchards once a month from September 2015 to August 2016 and used GIS and R to analyse both the general bat activity and foraging bat activity of the two main foraging guilds (open-air/clutter edge guild) in different land use types as well as total bat activity with respect to arthropod abundances. As reported in Chapter Two, results show that the overall clutter edge guild activity (number of passes) decreased with macadamia and orchard (all other fruit) cover in the macadamia high season (December to end of May) and increased with bush cover and distance to settlements (potential roosts) in the macadamia low season (June to end of November). Open-air guild activity increased with fallow cover (uncultivated grassland with scattered trees and shrubs) in the high season. Foraging activity (feeding buzzes) of the clutter edge guild increased with bush cover over the whole year. Total activity (both guilds) increased with abundance of true bugs (Hemiptera), including the main macadamia pests, and bush cover. Macadamia cover has a negative effect on the activity of the clutter edge guild in the high season, with low activity in the orchard center (high cover), and activity increasing in a linear way with decreasing orchard cover at the orchard edge (low cover). These results suggest that the clutter edge guild prefers foraging close to the edges of the orchards rather than in the center, while the open-air guild prefers semi-natural habitats (fallow). When numbers of pest arthropods drop in the macadamia orchards, the natural land use type, bush, becomes a more important foraging habitat and thereby increased the activity of the clutter edge guild. From June 2016 to July 2017, I scanned 31 bat houses, mounted on poles on six macadamia orchards, for bats or any other occupants such as wasps, birds and bees. Twenty-one multichambered bat houses of three slightly different chamber designs were erected on poles, in sets of three. Additionally, five bat houses of the type ‘Rocket box’, four bat houses in sets of two (black and white) and one colony bat house were erected. Bats were counted and visually identified to family or species level. From December 2016 to end of March 2017, three IButtons were installed to record temperature variation between one set of three bat houses. As reported in Chapter Three, results show that the central bat house in the set of three and the black bat house in the set of two had a significantly positive effect on bat house occupancy. There was a significant difference in the mean temperature between the houses in the set of three, with a significant difference in temperature of 0.46°C between the central and the first bat house. The three bat houses erected in sets varied slightly in their chamber design, with the central bathouse having the most chambers (six), while the bat houses to either side had less chambers (four), set at an angle or straight. This and the insulation to either side by the other bat houses is assumingly what caused the central bat house to be on average warmer. The Yellow-bellied house bat (Scotophilus dinganii) was by far the most recorded and the only species observed to co-habitat a bat house with another animal species, in particular honeybees. The study might confirm assumptions in that the microclimate of bat houses, respectively their insulation, sun exposure and color appear to be important factors influencing bat house occupancy. The two preferred bat houses in our study were the black, in the set of black and white, as well as the central, and on average warmest bat house, in the set of three. I collected bat faecal pellets with two different methods between July 2015 and April 2017 to determine the prevalence of pest insects in faecal pellets. Eighteen of the bat houses (in sets of three) on three different farms and two Egyptian slit-faced bat (Nycteris thebaica) roosts were fitted with trays in order to collect pellets from those occupied by bats. I noted occupancy of bat houses to species or family level to keep disturbance minimal. Additionally, I collected pellets from individuals captured by means of mist nets and harp traps. Four of the main pest-insects; the two-spotted stinkbug (Pentatomidae: Bathycoelia distincta), the green vegetable bug (Pentatomidae: Nezara viridula), the macadamia nut borer (Tortricidae: Thaumatotibia batrachopa) and the litchi moth (Tortricidae: Cryptophlebia peltastica), were collected from pheromone traps or after scouting for primer development and optimisation. After extracting DNA from the bat faecal samples the target regions were amplified in a multiplex PCR and fluorescently labelled PCR amplicons were analysed and interpreted. In order to verify multiplex analyses results, all samples were amplified with all four sets of primers in plates and those that produced amplicons were purified and sequenced. As reported in Chapter Four, results show that fragment analyses yielded a total of 63 out of 103 samples tested positive for pest insect species (61%) with a total of 92 positive fragments. Primer specificity could be confirmed to 100% for the sequences obtained for Bathycoelia distincta (26/26) and Nezara viridula (12/12) primers but not for all sequences obtained fot Cryptophlebia peltastica (18/30) and Thaumatotibia batrachopa (1/14) primers. One sample showed no positive fragments but contained a positive sequence for N. viridula. Three samples tested positive for one pest-species fragment but contained a positive sequence for a second pest-species (B. distincta, T. batrachopa and C. peltastica). Adding four positive fragments and one additional positive sequence to the data. This means that sequences of pest insect species were obtained from 54 out of the 103 samples (55.6%) with a total of 73 pest insect sequences. For the high season (December to end of May) a total of 37 positive fragments for the four pest insect species and 24 negative samples were yielded and for the a low season (June to end of November) a total of 36 positive fragments and 15 negative samples. Looking at the pest consumption of the different bat species or families, our results show that all of them foraged on pest insect species. Whereas, all species and families except Myotis bocagii and Rhinolophus simulator (for which N<2) foraged on both the Lepidopteran and Hemipteran pest species. Therefore, all families of bats of which faecal pellets were analysed for this study (Molossidae, Nycteridae, Rhinolophidae and Vespertilionidae) foraged on one or more of the four pest insect species. In summary, Chapter Five concludes that natural and semi-natural vegetation promote bat activity in macadamia orchards, and potentially bats' provision of the ecosystem service of pest control. In times of accelerating land use change, remnants of natural vegetation are important refuges and need to be maintained or restored to conserve bat species and promote their ecosystem services. The study also shows that bat activity might be improved by adding roosting opportunities to orchards. Warm and well-insulated bat houses mounted freestanding on poles and in sets appeared to work best in northern South Africa. Further research on co-habitation of bat houses and displacement behaviour as well as the potential importance of altitude and distance to water is needed. All of the species or families of bats from which faecal pellets were collected have been confirmed to forage on at least one of the four pest insects and the bat species have shown to be much more generalist and presumably opportunistic feeders than previously assumed. Thus, this study provides incentive and advice to farmers for a more integrated pest management approach (IPM).
NRF

MSCAGR (Plant Production)
Department of Plant Production
Indigenous trees play important roles in livelihoods for rural communities. Sclerocarya birrea and Berchemia discolor are indigenous in Africa and are used in rural communities for food and livestock feed, as well as for medicinal and construction purposes. These trees are subject to attack by insects, which can result in lower tree productivity. However, there is no documented information about insects found on both tree species in South Africa. This study investigated the seasonal abundance and diversity of insects on S. birrea and B. discolor in Tshikundamalema Area, Limpopo Province, South Africa. Five trees were selected for each of the two tree species at two sampling sites with different vegetation cover, one site mainly the woodland bushveld while the other site was savannah grasslands. Canopy fogging was used to sample insects. Insect samples were collected at one time point for each of the seasons: summer (February), autumn (May), winter (July) and spring (November). Insects were identified to morphospecies and Simpson’s diversity index was used to compare insect diversity on both trees. Analysis of variance was used to compare the abundance of insects across seasons. The most abundant insects were collected from Coleoptera, followed by Hemiptera, Hymenoptera, Diptera, Lepidoptera and Orthoptera. A total of 3259 insects belonging to the six Orders were collected. All specimens belonging to Coleoptera, Hemiptera and Hymenoptera (3216 in total) were identified to Family level, with a total of 97 morphospecies, belonging to 19 Families. Insects from Diptera, Lepidoptera and Orthoptera were not identified further due to their low numbers. The abundance and diversity of insects were affected by seasons, sites and tree species. The number of insects was high during the spring season with 1782 insects, and summer coming second with 1104 individuals, followed by autumn (238 insects), then winter (92). B. discolor sampled for a great number of insects (1741) as compared to S. birrea (1475). The woodland bushveld (1924 insects) surpassed the savannah grassland (1292 insects) site in terms of the insect numbers sampled.
NRF

Thesis (M. Phil. (Environmental Law and Management) -- University of Limpopo, 2010
According to the Ramsar Convention of 1971, Wetlands are areas of marshes, firm, peatlands or waterlogged. They are either natural or artificial. They have water that is static or flowing, fresh, brackish or salty and include areas of marine water with the depth, which at low tides does not exceed six meters. Wetlands are regarded as important ecological components of the natural environment because of their richness and ability to support life. Wetlands essentially catch, clean and preserve any water. They are able to reduce the severity of drought and floods by regulating a stream flow. They also control erosion and provide habitat for many different plant and animal species. Wetlands also serve as valuable source of water, fish and grazing for livestock. They are important nesting grounds for birds. Wetland resources are also known to be of socio-economic importance because they provide materials for furniture and craft’s work Ga-Riba wetlands are very important for the community of Ga –Riba because they provide them with food such as fish and birds. Some of the community members make baskets, hats and mats using wetlands grass. They also make pottery using clay from the wetlands. During winter the wetlands are used as areas where traditional initiation for Ga-Riba girls is perfomed. Some people own fields within the wetlands on which they cultivate vegetables, maize and other crops. They also use wetland as grazing areas for their domestic animals such as cattle and goats. The Ga-Riba wetlands are being invaded by one of the alien plant called Populus alba L (Poplar). This type of alien plant, like other alien plants disturbs the ecological stability of the wetlands. Findings of the tests conducted on soil and water indicated that Poplars are changing the nature of the soil and the water of the wetlands. Vegetation survey showed that, wetlands had less vegetation than they were supposed to. With regard to legal instruments to control the invasion of wetlands by alien plants, findings showed that there are insuffient legal instruments which can be utilized.

M.Sc.
Invasive species are a considerable threat to ecosystems globally, especially on islands where species diversity can be relatively low. Understanding the drivers of invasion is the first step towards an adequate management plan. Although Darwin’s naturalisation hypothesis has fuelled our understanding in this regard, several studies provided mixed results, suggesting that invasion success might be context-dependent. The main objectives of this study are two-fold: (1) testing Darwin hypothesis on Robben Island, and (2) investigating the relative role of invasive alien plants on phylogenetic diversity (PD) loss in native community. I sampled extensively the flora of the island, and using a Bayesian analysis, I reconstructed its phylogeny based on two plastid DNA loci, rbcLa and matK. I also surveyed a total of 127 plots of 50 x 50 m (i.e. local communities) where species presence/absence was recorded. Analysing phylogenetic patterns of the native and invasive floras at both regional (phylogeny level) and smaller scales (plots level), I found that invasive species are, on average, more distantly related to the native communities, giving strong support to the hypothesis tested. Furthermore I found that native communities have accumulated lower PD than alien communities; and that local communities are more overdispersed than expected. These findings suggest that competitive interactions might be the major ecological forces shaping plant communities, with the possibility of alien being higher competitors than native, and therefore decreasing native plant diversity. The implications of these findings for the recovery of native plants are also discussed. Key words: Invasion biology - Darwin’s naturalisation hypothesis - Phylogenetic diversity - Community structure - Conservation - Robben Island, South Africa.

Medicinal plants of Thulamela municipality are experiencing challenges due to human activities, resulting in some of the medicinal plants becoming difficult to find, declining, endangered or even extinct. Unsustainable harvesting is threatening the survival of certain medicinal plant species used as a source of primary healthcare in the area. This study investigates aspects related to traditional healers' perceptions with regard to collection, ethnobotanical importance and conservation status of indigenous medicinal plants used by traditional healers around Thulamela municipality. Information on medicinal plants was gathered by means of semi-structured interviews, field walks, personal observation and a literature review. A total of 90 medicinal plant species, which belong to 47 families, from a total of 82 genera commonly used by traditional healers to treat different ailments, were recorded. About 87% of traditional healers indicated that some medicinal plants are difficult to find; only 13% of healers did not experience difficulties in finding some medicinal plants.
Environmental Sciences
M. Sc. (Ornamental Horticulture)

MAAS
Department of African Studies
Medicinal plants are now used as a livelihood activity by the marginalized urban poor communities in various places around the world. Indigenous knowledge in medicinal plants is owned and practiced by the knowledge holders for different purposes. It entails the passing of skills and knowledge from one generation to the other within a specific geographical area. Vhembe district is well known to be rich in plants and the people own the rich knowledge in medicinal plants. However, much debate has emerged around the effectiveness of indigenous knowledge in alleviating poverty levels amongst the communities. Despite the wealth and abundance of indigenous knowledge in medicinal plants, Limpopo Province is still rated as one of the poorest provinces in South Africa. Consequently, this study sought to investigate the utilization of indigenous knowledge by medicinal plant vendors in Thohoyandou, Vhembe District. The study has used the qualitative research approach by means of an interview schedule and semi-structured interviews to collect data from a sample of 10 respondents, who were selected using the purposive and snowballing non-probability sampling techniques. The data collected was analyzed thematically. The findings in this study revealed that the sale of medicinal plants by vendors is a source of employment done mostly by men than women who have been engaged in this form of street trading for more than 23 years. The CBD in Thohoyandou is deemed preferably by the medicinal plant vendors as it is busy and attracts more customers. Although the medicinal plant vendors make a living out of selling their practice, they are not fully supported by key stakeholders. The research therefore concluded that the use of indigenous knowledge by medicinal plant vendors has an important role to play in creating employment for indigenous knowledge holders and as such should be invested in. The study recommends that key stakeholders such as the municipality, private companies, business support groups and the government should take the initiative to upgrade, develop and invest in indigenous knowledge v holders of medicinal plants to reduce unemployment in the province and avoid the risk of extinction of the knowledge. Lastly, more research should be conducted on a much bigger scale
NRF

Human related activities have influenced the rivers of the southern Western Cape since as early as the 1700’s. As there is no detailed information available on ecological status of the Holsloot River, a tributary of the Breede River, this study aimed to gain insight into the effect of impacts associated with human activities on the habitat integrity of this river. The study intended to understand how seasonal changes, catchment characteristics and events are reflected in the ecological status of habitats along the river by applying bio-monitoring and river health measurements at selected sites in the upper, middle and lower reaches of the Holsloot River and compare the results to that of an undisturbed reference site. Results obtained in this study are compared with data gathered in 2008/2009 to determine if the ecological status of the river had changed in the period between the two sampling times. The study included assessment of the ecological status of the river based on standard bio-monitoring protocol (SASS5, IHI, IHAS and VEGRAI) as well as in situ water quality analysis (pH, dissolved oxygen, electrical conductivity and total dissolved solids). The construction of the instream Stettynskloof Dam changed the configuration of the riparian zone and river channel in the upper catchment area. Agricultural- and other human related activities, with consequent water abstraction, non-point-source pollution, loss of riparian vegetation, as well as dense stands of alien invader plants influence flow patterns and affects river ecology, especially in the dry summer months. Providing sufficient stream flow and adequate water levels, human related activities can create a larger variety of habitat types available that can support larger biodiversity and higher productivity. The level of inundation and stream flow, influenced by water abstraction as well as irrigation return-flow from extensive drainage systems especially in the dry months, contribute to the loss of biodiversity in the middle and lower reaches of the river. Where the upper reaches of the river are largely natural with few modifications, the habitat integrity deteriorates in the middle reaches so much so that ecosystem functioning are collectively impaired in lower reaches due to human related impacts. Sensitive macro-invertebrates found at lower seriously impacted parts of the river however, were in all probability washed down from lower impacted upstream habitats and may expectedly be able to again occupy habitats downstream if water quality and habitat availability improves.
Environmental Sciences
M. Sc. (Environmental Science)

Herbivores have a significant influence on their environment. Factors that influence herbivore distribution in a landscape are important for conservation. Artificial water provision is one such factor, with water sources being focal points of herbivore activity. Variation between herbivore utilisation of different waterhole types and habitat integrity surrounding the different waterholes is assessed in this study. Correlations are drawn between herbivore utilisation and habitat integrity to quantify the impact that artificial waterholes have on the landscape. A scoring system is devised to investigate the various factors affecting vegetation around artificial waterholes. Results show that there are significant variations between herbivore utilisation for different artificial waterhole types, as well as significant variation in habitat integrity surrounding the different waterhole types. Distance between waterholes and drainage lines, and utilisation by specific herbivore species have a significant impact on habitat integrity - specifically affecting veld condition and disturbance observed on woody plant species. A habitat score that was created by combining data from both the herbaceous and woody layers is not affected by waterhole type, distance from waterholes, or the different herbivore species utilising the different waterhole types. Earth dams have the greatest impact on surrounding vegetation and are the most utilised waterhole type. Closures of earth dams are not recommended due to their importance to herbivores. Less utilised waterhole types are also important, mitigating the impact of herbivore damage to vegetation at earth dams.
Environmental Sciences
M. Sc. (Nature Conservation)