Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Invasive alien plants (IAPs) reduce streamflow and threaten the biodiversity of South Africa’s Cape Floristic
Region. Up-to-date information on invasive vegetation is required for land management agencies to
formulate policies and make appropriate resource management decisions. Invasion maps are typically not
updated often enough because of the time and expenses required to do so. As a result, invasion maps for
South Africa are limited to coarse resolution data or isolated small scale studies. Invasive alien plants
change the landscape by destabilizing catchments and thereby increasing soil erosion, altering fire regimes
and hydrology, as well as changing the physical and chemical composition of the soil. Information on IAPs is
needed at a landscape scale. Remote sensing is a powerful tool that can be used to characterise landscapes
in a biologically meaningful manner. The Normalised Difference Vegetation Index (NDVI) was used to create
an up-to-date invasion map of the Agulhas Plain, lying at the heart of the species rich Cape Floristic Region.
This information was combined with actual evapotranspiration data from the Surface Energy Balance
Algorithm for Land (SEBAL) study done by Water Watch and the Council for Scientific and Industrial
Research. The results showed that invasive vegetation uses more water than natural fynbos vegetation and
that the greatest amount of water would be made available by clearing the invaded deep sands on the
Agulhas Plain. These deep sand areas conflict with the priority areas of the Working for Water programme.
This IAP eradication programme targets sparsely invaded upland areas for long-term sustainability. The
recommendation of this study is to clear invaded wetland and riparian areas as these zones yield the
greatest hydrological benefit per hectare and meet the priorities of Working for Water. Overall, 36 million
cubic meters of water would be made available by clearing the Agulhas Plain. It can be concluded that there
is a significant hydrological benefit to clearing invasive alien vegetation on the Agulhas Plain. / AFRIKAANSE OPSOMMING: Indringerplante (IP) verminder stroomvloei en bedreig die biodiversiteit van Suid-Afrika se Kaapse
Floristiese Streek. Die nuutste inligting oor uitheemse plantegroei is nodig vir
grondbestuuragentskappe om beleide te formuleer vir die neem van toepaslike hulpbronbestuur
besluite. As gevolg van die tyd en uitgawes wat nodig is om indringingskaarte op te dateer, word
dit gewoonlik nie dikwels genoeg gedoen nie. Dus is indringingskaarte vir Suid-Afrika beperk tot
growwe resolusie data of geïsoleerde kleinskaal studies. Indringerplante verander die landskap
deur opvangsgebiede te destabiliseer en sodoende te lei tot gronderosie, verandering van
vuurregimes en hidrologie, sowel as die verandering in die fisiese en chemiese samestelling van
die grond. Inligting oor IP is nodig op 'n landskapskaal. Afstandswaarneming is 'n kragtige tegniek
wat gebruik kan word om landskappe op 'n biologies betekenisvolle manier te karakteriseer. Die
Normalised Difference plantegroei-indeks (NDVI) is gebruik om 'n opgedateerde indringingskaart
van die Agulhas-vlakte, wat in die hart van die spesiesryke Kaapse Floristiese Streek lê, te skep.
Hierdie inligting is gekombineer met die werklike evapotranspirasie data vanaf die Surface Energy
Balance Algorithm for Land (SEBAL) studie gedoen deur Water Watch en die Raad vir
Wetenskaplike en Nywerheidnavorsing. Die resultate het getoon dat uitheemse plantegroei meer
water gebruik as natuurlike fynbosplantegroei en dat die grootste hoeveelheid van hierdie water
beskikbaar gestel sal word deur IP op diepsand op die Agulhas-vlakte skoonte maak. Hierdie
diepsand areas is in konflik met die prioriteitsgebiede van die Werk vir Water-program. Hierdie IP
uitroeiingsprogram fokus op yl ingedringde berggebiede vir langtermyn volhoubaarheid. Die
aanbeveling van hierdie studie is om duidelik ingedringde vleilande en oewergebiede skoon te
maak, siende dat hierdie sones die hoogste opbrengs en die grootste hidrologiese voordeel per
hektaar bied, en voldoen aan die prioriteite van Werk vir Water. In totaal sou 36 miljoen kubieke
meter water beskikbaar gestel word deur die skoonmaak van die Agulhas-vlakte. Dus kan dit
afgelei word dat die verwydering van hidrologiese indringerplante op die Agulhas-vlakte 'n
beduidende voordeel sal inhou.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6855 |
| Date | 03 1900 |
| Creators | Nowell, Megan Sarah |
| Contributors | Esler, Karen J., Le Maitre, David C., University of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 93 p. : ill., maps |
| Rights | University of Stellenbosch |
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