The Properties and Effects of Dust from Unpaved Roads on Vegetation and Microbes in the Karoo
| dc.contributor.advisor | Jacobs, Shayne Martin | en_ZA |
| dc.contributor.advisor | Crous, Casparus J. | en_ZA |
| dc.contributor.advisor | Milton, Suzanne | en_ZA |
| dc.contributor.author | Arendse, Lee-Roy | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. | en_ZA |
| dc.date.accessioned | 2020-02-26T13:16:16Z | |
| dc.date.accessioned | 2020-04-28T15:12:37Z | |
| dc.date.available | 2020-02-26T13:16:16Z | |
| dc.date.available | 2020-04-28T15:12:37Z | |
| dc.date.issued | 2020-03 | |
| dc.description | Thesis (MScConsEcol)--Stellenbosch University, 2020. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: There is minimal information on how dust from unpaved roads affects plant communities in the semi-arid Nama and Succulent-Karoo. One site per biome were used for conducting research, including the Square Kilometre Array (SKA), falling within the Nama Karoo biome and Wolwekraal Nature Reserve, falling within the Succulent Karoo biome. Each site was divided into four distance categories (D1 = 0–20 m; D2 = 20–100 m; D3 = 100–400 m; and D4 = 400–1000 m) from their respective unpaved roads. Within each distance category Modified Wilson and Cooke (MWAC) samplers were placed, on the soil surface and 1,3 m above the surface using steel rods and soil samples (including the road) were taken to a depth between 5 to 10 cm. After two months of dust sampling, samplers were collected to analyze the physical characteristics of dust (load and particle size); and microbial characteristics (fungal and bacterial composition and species richness) were determined in both the samplers and soil samples. Leaves from two shrubs (Pteronia glauca and Rhigozum trichotomum) in SKA and one shrub (Pteronia pallens) and a succulent (Ruschia spinosa) in Wolwekraal were sampled in each distance category. The leaves were analyzed for their leaf specific area (SLA), leaf stable carbon and nitrogen isotopes and metal ion deposits (Cu, Zn Cr, Pb and Ni). Results indicated unique patterns between sites. Mean dust loads were highest closest to the road (0-20 m) at both sites, and decreasing mean dust loads and particle size with increasing distance from the road were evident at SKA whereas mean dust loads and particle size displayed an inconsistent pattern along the distance gradient at Wolwekraal. Among the five metals Cr, Pb and Ni are carcinogenic and only these three metals had the highest concentration in the distance category closest to the road (0-20 m). Despite high dust loads and metal concentrations in the distance closest to the road it did not seem to significantly impact, with the exception of δ15N in P. glauca at SKA, the physiological indicators included (δ15N, δ13C, and SLA), which suggests only minor water and nitrogen-use impacts on plants, due to dust deposition. Dust transported from the road had low microbial species richness and influenced the samplers in the 0-20 m zone and associated soil samples by diminishing their microbial richness and diversity at SKA. Understanding the effects of dust pollution on plants and soil microorganisms would aid conservationists to better understand the nature of the environmental impacts facing arid and dust-prone areas. Based on the findings of the study it is recommended that implementation of dust mitigation techniques is applied in order to minimize dust generation from unpaved roads. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Daar is minimale informasie wat focus op hoe stof van ongeplaveide paaie die plant gemeenskap in die semi-droë Nama en Sukkulent-Karoo beinvloed. Navoring het plassgevind binne een plek per bioom, insluitend die Square Kilometre Array (SKA), wat binne die Nama-Karoo val en die Wolwekraal Natuurreservaat, wat binne die Sukkulent-Karoo val. Vanaf die respektiewe ongeplaveide paaie was elke plek in vier afstand kategorieë verdeel (D1 = 0–20 m; D2 = 20–100 m; D3 = 100–400 m; and D4 = 400–1000 m). Binne elke afstand kategorieë was Modified Wilson and Cooke (MWAC) opvangers gepelaas, op die grondoppervlakte en 1,3 m bo die grondoppervlakte met behulp van staalstawe en grondmonsters was geneem tot 'n diepte tussen 5 en 10 cm. Na twee maande van stofopneming, was die stofmonsers versamel om te analiseer wat die fisiese eienskappe van stof (lading en partikelgrootte) was; en mikrobiese eienskappe (fungus- en bakteriële samestelling en spesierykheid) was vir beide stofmonsters and grondmonsters bepaal. Blare van twee struikplante (Pteronia glauca en Rhigozum trichotomum) by SKA en een struikplant (Pteronia pallens) en een vetplant (Ruschia spinosa) in Wolwekraal was in elke afstand kategorieë versamel. Die blare was geanaliseer vir hul spesifieke blaaroppervlakte, stabiele koolstof- en stikstofisotope en metaalioonafsettings (Cu, Zn Cr, Pb, and Ni). Gemiddelde stoflading was hoogste naaste aan die pad (0-20 m) by beide plekke, en n afneming van stoflading en partikelgrootte met toenemende afstand vanaf die pad was duidelik by SKA, maar gemiddelde stoflading en partikelgrootte het n inkonsekwente patroon met die afstandgradiënt by Wolwekraal vertoon. Van die vyf metale dra Cr, Pb en Ni karsinogeniese eienskappe en hierdie metale was die hoogste in konsentrasie by die afstand naaste aan die pad (0-20 m), en het nie n aansienlike impak, met die uitsondering van 15N in P. glauca by SKA, op die fisiologiese aanwysers (δ15N, δ13C, and SLA) van die plante gehad nie, wat aandui dat daar slegs 'n geringe invloed op die gebruik van water en stikstof op plante was, as gevolg van stofneerlegging. Stof wat vanaf die pad vervoer was het lae mikrobiese spesierykheid gehad en dit het stofmonsters in die 0-20 m afstand en gepaardgaande grondmonsters beïnvloed deur hul mikrobiese spesierykheid en diversiteit by SKA te verminder. Om die gevolge van stofbesoedeling op plante en grondmikroörganismes te verstaan, sal natuurbewaarders help om die aard van die omgewingsimpakte wat droë en stofgevoelige gebiede in die gesig staar, beter te verstaan Op grond van die bevindinge van die studie word dit aanbeveel dat die toepassing van stofversagtingstegnieke toegepas word om die opwekking van stof vanaf ongeplaveide paaie tot 'n minimum te beperk. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | x, 115 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/108408 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Unpaved roads | en_ZA |
| dc.subject | Karoo, dust, heavy metals, isotopes, microbes | |
| dc.subject | Gravel roads -- Karoo | en_ZA |
| dc.subject | Roads -- Karoo | en_ZA |
| dc.subject | Microorganisms | en_ZA |
| dc.subject | Dust | en_ZA |
| dc.subject | Vegetation -- Effect of roads on | en_ZA |
| dc.subject | Plants -- Effect of heavy metals on | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | The Properties and Effects of Dust from Unpaved Roads on Vegetation and Microbes in the Karoo | en_ZA |
| dc.type | Thesis | en_ZA |