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Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.

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Main Author: Nowell, Megan Sarah
Other Authors: Esler, Karen J.
Format: Thesis
Language:en_ZA
Published: Stellenbosch : University of Stellenbosch 2011
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access_status_str Open Access
author Nowell, Megan Sarah
author2 Esler, Karen J.
author_browse Esler, Karen J.
Nowell, Megan Sarah
author_facet Esler, Karen J.
Nowell, Megan Sarah
author_sort Nowell, Megan Sarah
collection Thesis
dc_rights_str_mv University of Stellenbosch
description Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.
format Thesis
id oai:scholar.sun.ac.za:10019.1/6855
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:45:52.267Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2011
publishDateRange 2011
publishDateSort 2011
publisher Stellenbosch : University of Stellenbosch
publisherStr Stellenbosch : University of Stellenbosch
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/6855 Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa Nowell, Megan Sarah Esler, Karen J. Le Maitre, David C. University of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. Invasive alien vegetation -- Siouth Africa -- Agulhas Plain Clearing invasive vegetation - South Africa -- Agulhas Plain Water management -- South Africa -- Agulhas Plain Dissertations -- Conservation ecology and entomology Theses -- Conservation ecology and entomology 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. Masters 2011-03-02T13:27:08Z 2011-03-14T08:48:03Z 2011-03-02T13:27:08Z 2011-03-14T08:48:03Z 2011-03 Thesis http://hdl.handle.net/10019.1/6855 en_ZA University of Stellenbosch 93 p. : ill., maps application/pdf Stellenbosch : University of Stellenbosch
spellingShingle Invasive alien vegetation -- Siouth Africa -- Agulhas Plain
Clearing invasive vegetation - South Africa -- Agulhas Plain
Water management -- South Africa -- Agulhas Plain
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
Nowell, Megan Sarah
Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title_full Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title_fullStr Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title_full_unstemmed Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title_short Determining the hydrological benefits of clearing invasive alien vegetation on the Agulhas Plain, South Africa
title_sort determining the hydrological benefits of clearing invasive alien vegetation on the agulhas plain south africa
topic Invasive alien vegetation -- Siouth Africa -- Agulhas Plain
Clearing invasive vegetation - South Africa -- Agulhas Plain
Water management -- South Africa -- Agulhas Plain
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
url http://hdl.handle.net/10019.1/6855
work_keys_str_mv AT nowellmegansarah determiningthehydrologicalbenefitsofclearinginvasivealienvegetationontheagulhasplainsouthafrica