Sustainable rehabilitation can be compromised by the inability of vegetation to survive in hostile mine wastes on a long-term basis. The adverse chemical and physical properties of mine wastes, together with extreme pH conditions and lack of nutrients, provide poor growth conditions for vegetation during seed development and germination. This raises concern for the long-term survival of vegetation through means of seed production when under stress from the punitive properties of mine wastes. Seed vigour is a function of a variety of factors to which the parent plant is subjected during seed formation and maturation. Environmental conditions experienced by the maternal plant during the growth season plays a significant role in determining subsequent germination rates in seeds. Traits of offspring seed depend on the abiotic environment attributed by the growth medium during seed development and maturation The general aim of this study was to determine the viability of seed produced by a previous generation of grass species established in eight different mine wastes and two soils (namely: gypsum wastes; gold tailings with low pyrite content; gold tailings with high pyrite content; platinum tailings; kimberlite mine waste; fluorspar mine waste; andalusite mine waste; coal discard; red soil; and vertic soil) in order to identify suitable species for specific mine wastes to ensure long-term survival through means of seed production. The species selected included: Eragrostis curvula; Eragrostis tef; Cenchrus ciliaris; Eragrostis curvula; Digitaria eriantha; Cynodon dactylon; Chloris gayana; Hyparrhenia hirta; and Sorghum bicolor. The progeny seed‟s viability and ability to germinate were determined through a pot trial study and additional germination testing at the laboratory of Advance Seed (Pty) Ltd. (AS). The germination results were correlated with the growth media analyses by statistical non-parametric correlations which indicated several significant correlations among the growth media properties themselves, and with the germination of the progeny seed. C. gayana (Rhodes grass) seed had poor germination percentages, especially seed harvested from Rhodes grass grown in acidic wastes. Seed harvested from each of the E. curvula grasses grown in various mine wastes, had excellent germination percentages. According to the Repeated Measures ANOVA statistical analysis, there was a significant influence of the growth media in which the parent grass were grown as a variable on the germination of the progeny seed batches from S. bicolor, C. ciliaris, C. gayana, and D. eriantha, indicating that the environmental factors as attributed by the growth media, i.e. the eight different mine waste materials and two soils, and experienced by the maternal plant, did indeed influence the germination of progeny seed. However, it was found that significant correlations between the properties of the growth media and the germination of the progeny seed, was species dependent. The second general aim for this study was to evaluate above-ground re-growth of parent plants after cutting in the mine waste materials and soil types mentioned above. The ability of established grasses to re-grow after a cutting event was determined by cutting the above-ground biomass of the parent grasses, after which it was scored according observable above-ground growth in the following growth season. The measurement of re-growth was subjectively done by scoring the grasses according to observable above-ground biomass. Re-growth was observed for all the perennial grass species. This can be ascribed to the grasses showing resilience to stress factors attributed by the growth media; or new grasses which emerged from seed that collected in the pots, being mistaken for re-growth; or new emerging grasses from the nodes of stolons and/or rhizomes being mistaken for re-growth. However, the emergence of new grasses was an indicator of good health, as biomass allocation to rhizomes and stolons is reduced under low nutrient availability and stress conditions. Therefore the emergence of new grasses is indicative that the plant is either tolerant to stress conditions or that the plant adapted to the restriction of growth due to the roots being bound to the size of the pot. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Sustainable rehabilitation can be compromised by the inability of vegetation to survive in hostile mine wastes on a long-term basis. The adverse chemical and physical properties of mine wastes, together with extreme pH conditions and lack of nutrients, provide poor growth conditions for vegetation during seed development and germination. This raises concern for the long-term survival of vegetation through means of seed production when under stress from the punitive properties of mine wastes. Seed vigour is a function of a variety of factors to which the parent plant is subjected during seed formation and maturation. Environmental conditions experienced by the maternal plant during the growth season plays a significant role in determining subsequent germination rates in seeds. Traits of offspring seed depend on the abiotic environment attributed by the growth medium during seed development and maturation The general aim of this study was to determine the viability of seed produced by a previous generation of grass species established in eight different mine wastes and two soils (namely: gypsum wastes; gold tailings with low pyrite content; gold tailings with high pyrite content; platinum tailings; kimberlite mine waste; fluorspar mine waste; andalusite mine waste; coal discard; red soil; and vertic soil) in order to identify suitable species for specific mine wastes to ensure long-term survival through means of seed production. The species selected included: Eragrostis curvula; Eragrostis tef; Cenchrus ciliaris; Eragrostis curvula; Digitaria eriantha; Cynodon dactylon; Chloris gayana; Hyparrhenia hirta; and Sorghum bicolor. The progeny seed‟s viability and ability to germinate were determined through a pot trial study and additional germination testing at the laboratory of Advance Seed (Pty) Ltd. (AS). The germination results were correlated with the growth media analyses by statistical non-parametric correlations which indicated several significant correlations among the growth media properties themselves, and with the germination of the progeny seed. C. gayana (Rhodes grass) seed had poor germination percentages, especially seed harvested from Rhodes grass grown in acidic wastes. Seed harvested from each of the E. curvula grasses grown in various mine wastes, had excellent germination percentages. According to the Repeated Measures ANOVA statistical analysis, there was a significant influence of the growth media in which the parent grass were grown as a variable on the germination of the progeny seed batches from S. bicolor, C. ciliaris, C. gayana, and D. eriantha, indicating that the environmental factors as attributed by the growth media, i.e. the eight different mine waste materials and two soils, and experienced by the maternal plant, did indeed influence the germination of progeny seed. However, it was found that significant correlations between the properties of the growth media and the germination of the progeny seed, was species dependent. The second general aim for this study was to evaluate above-ground re-growth of parent plants after cutting in the mine waste materials and soil types mentioned above. The ability of established grasses to re-grow after a cutting event was determined by cutting the above-ground biomass of the parent grasses, after which it was scored according observable above-ground growth in the following growth season. The measurement of re-growth was subjectively done by scoring the grasses according to observable above-ground biomass. Re-growth was observed for all the perennial grass species. This can be ascribed to the grasses showing resilience to stress factors attributed by the growth media; or new grasses which emerged from seed that collected in the pots, being mistaken for re-growth; or new emerging grasses from the nodes of stolons and/or rhizomes being mistaken for re-growth. However, the emergence of new grasses was an indicator of good health, as biomass allocation to rhizomes and stolons is reduced under low nutrient availability and stress conditions. Therefore the emergence of new grasses is indicative that the plant is either tolerant to stress conditions or that the plant adapted to the restriction of growth due to the roots being bound to the size of the pot. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Plants have been used for centuries to treat a wide range of ailments in the history of all civilizations. However, a growing interest in medicinal plants requires appropriate management to prevent over-exploitation of target species. The challenge for scientists is to find equilibrium between resource exploitation and the maintenance of viable populations of target species. Sustainability of use requires an understanding of the ecological, economic and socio-cultural aspects of resource use and the interaction between these factors. This research focuses on the ecological and socio-cultural aspects required to underwrite species-specific sustainable harvesting systems for bark used for traditional medicine. The social survey conducted in the form of structured interviews with traditional healers reported 69 plant species used for medicinal purposes in the southern Cape. The results suggested that resource users are aware of the increase in demand for medicinal plants in general, attributing this to an increasing recognition of traditional medicines and increasing prevalence of diseases. Ocotea bullata (Endangered), Curtisia dentata (Nearly Threatened) and Rapanea melanophloeos (Declining), as well as Siphonochilis aethiopicus (Critically Endangered), Elaeodendron transvaalense (Near Threatened) and Cassipourea flananganii (Endangered) that do not occur in the area naturally, were identified as species in high demand for their medicinal bark properties. Given the high demand and concerns about over-exploitation, a need for further ecological research to develop sustainable harvest systems was identified. Two species, O. bullata and C. dentata, were selected from an earlier study on the response of several species to bark stripping, that was confined to a study period of three years after treatment. With this current study tree response to bark stripping and harvesting impact were assessed over a period of ten years to reveal the intra and inter-specific difference of wound occlusion (wound closure through bark-regrowth) and the anatomical decay consequences of bark stripping. This is, to the knowledge of the author, the first study to evaluate the structural-tree pathogen interaction following bark stripping on medicinal tree species in Africa. The results revealed species-specific differences in terms of both wound closure and efficiency in decay containment. O. bullata had a significantly better wound occlusion rate and a lower extent of decay. The relationship between tree diameter growth and the rate of wound occlusion allowed for the formulation of a preliminary model that will assist forest managers in developing bark harvest systems. Smaller trees showed poor bark regrowth and a significantly higher mortality, which suggest that a minimum tree size for harvesting needs to be stipulated in the harvest prescriptions. In contrast, C. dentata showed a much higher volume of decay within the stem, poor bark regrowth and a significantly higher mortality of bark-stripped trees. In conclusion, the harvesting of bark for C. dentata through bark stripping is not viable, and alternatives should be explored. O. bullata has a much greater potential for strip harvesting, both in terms of bark regrowth and the containment of wood decay following wounding. / AFRIKAANSE OPSOMMING: Beskawings gebruik al vir eeue plante vir die behandeling van ‘n verskeidenheid van kwale. Die toenemende belangstelling in medisinale plante vereis egter oordeelkundige bestuur om die oorbenutting van teikenspesies te voorkom. Die uitdaging vir wetenskaplikes is om 'n balans tussen die benutting van hulpbronne en die handhawing van lewensvatbare populasies van teikenspesies te bewerkstellig. Standhoudende benutting vereis insig in die ekologiese, ekonomiese en sosio-kulturele aspekte van hulpbronbenutting, en die interaksie tussen hierdie faktore. Hierdie navorsing fokus op die ekologiese en sosio-kulturele aspekte wat nodig is om spesie-spesifieke, standhoudende oesstelsels vir bas wat vir tradisionele medisyne gebruik word, te onderskryf. Die sosiale opname, in die vorm van gestruktureerde onderhoude met tradisionele genesers, dui op 'n totaal van 69 plantspesies wat vir medisinale doeleindes in die Tuinroete gebruik word. Gebruikers is oor die algemeen bewus van die toenemende vraag na medisinale plante, en skryf dit toe aan groter erkenning van tradisionele medisyne en ‘n toename in siektes. Ocotea bullata (Bedreig), Curtisia dentata (Byna bedreig) en Rapanea melanophloeos (Afnemend), asook drie spesies wat nie natuurlik in die gebied voorkom nie, Siphonochilis aethiopicus (Kritiek bedreig), Elaeodendron transvaalense (Byna bedreig) en Cassipourea flananganii (Bedreig), is geïdentifiseer as spesies in groot aanvraag weens hul medisinale eienskappe. Die hoë aanvraag en kommer oor oorbenutting het gelei tot die behoefte vir verdere ekologiese navorsing vir die onwikkeling van oesstelsels vir die spesies. Twee spesies, O. bullata en C. dentata, is geselekteer van ‘n vroeëre studie oor die reaksie van verskeie spesies op basstroping wat beperk was tot ‘n studieperiode van drie jaar na behandeling. Die huidige studie was daarop gemik om die reaksie en impak oor ‘n periode van 10 jaar na behandeling te bepaal, en die intra- en inter-verskille van wond sluiting (wond sluiting deur die hergroei van die bas) en anatomiese verrotting na basstroping te beskryf. Dit is, tot die kennis van die outeur, die eerste studie om die struktuur-boompatogeen interaksie na basstroping op medisinale boomsoorte in Afrika te beskryf. Die resultate dui op spesie-spesifieke verskille in beide wond en die beperking van houtverrotting. O. bullata het ‘n betekenisvolle hoër tempo van wondsluiting en effektiwiteit in die beperking van houtverrotting. Die korrelasie tussen boomdeursnee-aanwas en die tempo van wondsluiting het die ontwikkeling van ‘n voorlopige model om bosbestuurders te help met die ontwikkeling van oesvoorskrifte, moontlik gemaak. Kleiner bome toon swak bas-hergroei en betekenisvolle hoër mortaliteit, wat aandui dat ‘n minimum grootte vir oesbome neergelê behoort te word in oesvoorskrifte. In teenstelling toon C. dentata ‘n baie groter mate van houtverrotting, het swak bas-hergroei, en ‘n betekenisvolle hoër mortaliteit van gestroopte bome. Ter afsluiting, die oes van C. dentata deur basstroping is nie lewensvatbaar nie en alternatiewe behoort ondersoek te word. O. bullata het ‘n groter potensiaal vir standhoudende basstroping, beide in terme van bas-hergroei en die beperking van houtverrotting na oes.