Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos

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dc.contributor.advisorBond, William Jen_ZA
dc.contributor.advisorPower, Simon Cen_ZA
dc.contributor.authorNortje, Gen_ZA
dc.date.accessioned2015-09-15T10:33:09Z
dc.date.available2015-09-15T10:33:09Z
dc.date.issued2013en_ZA
dc.description.abstractThe boundary between forest and fynbos vegetation in the Southern Cape of South Africa present a dynamic ecotone in which forest has previously been noted to have expanded into fynbos territory. Forest colonization of fynbos has been shown to be primarily a function of nutrients and light environments in the understory which may or may not be conducive for the growth of forest species. Additionally, it is understood that fire regime is the primary agent in determining forest/fynbos boundaries. Virgilia oroboides is a fast-growing leguminous tree confined to the margin between forest and fynbos. It has long been thought to facilitate the growth of forest species through the heavy shading and nutrient enrichment of soils; both of which facilitate the growth of forest seedlings. Furthermore, V. oroboides is predicted to reduce fuel loads and as a result prevent fire penetration of forests. These possible functions were tested by sampling soils, nutrient content of leaves and the shade cast by plants 18 months after a burn on a forest margin near Swellendam, Southern Cape. In addition, the effects of varying density of Virgilia on surrogates for fuel biomass, and forest seedling growth, were observed at Silvermine on the Cape Peninsula. Shaded environments produced by V. oroboides are shown to have detrimental effects on the growth of fynbos, while facilitating the growth of forests. V. oroboides had the highest soil nutrient enrichment potential of all species investigated and is therefore predicted to produce nutrient cycling processes conducive to the growth and regeneration of forests. Estimates of fuel in the understory of V. oroboides are predicted to reduce fynbos fire severity upon reaching the margin. These results suggest that Virgilia does indeed facilitate forest tree species more than light-demanding fynbos species so that its presence should result in greater stability or slow expansion of forests into fynbos. If supported by further work, this facilitative role of Virgilia has management implications for the conservation of fynbos and forests in the Southern Cape of South Africa.en_ZA
dc.identifier.apacitationNortje, G. (2013). <i>Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/14024en_ZA
dc.identifier.chicagocitationNortje, G. <i>"Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013. http://hdl.handle.net/11427/14024en_ZA
dc.identifier.citationNortje, G. 2013. Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Nortje, G AB - The boundary between forest and fynbos vegetation in the Southern Cape of South Africa present a dynamic ecotone in which forest has previously been noted to have expanded into fynbos territory. Forest colonization of fynbos has been shown to be primarily a function of nutrients and light environments in the understory which may or may not be conducive for the growth of forest species. Additionally, it is understood that fire regime is the primary agent in determining forest/fynbos boundaries. Virgilia oroboides is a fast-growing leguminous tree confined to the margin between forest and fynbos. It has long been thought to facilitate the growth of forest species through the heavy shading and nutrient enrichment of soils; both of which facilitate the growth of forest seedlings. Furthermore, V. oroboides is predicted to reduce fuel loads and as a result prevent fire penetration of forests. These possible functions were tested by sampling soils, nutrient content of leaves and the shade cast by plants 18 months after a burn on a forest margin near Swellendam, Southern Cape. In addition, the effects of varying density of Virgilia on surrogates for fuel biomass, and forest seedling growth, were observed at Silvermine on the Cape Peninsula. Shaded environments produced by V. oroboides are shown to have detrimental effects on the growth of fynbos, while facilitating the growth of forests. V. oroboides had the highest soil nutrient enrichment potential of all species investigated and is therefore predicted to produce nutrient cycling processes conducive to the growth and regeneration of forests. Estimates of fuel in the understory of V. oroboides are predicted to reduce fynbos fire severity upon reaching the margin. These results suggest that Virgilia does indeed facilitate forest tree species more than light-demanding fynbos species so that its presence should result in greater stability or slow expansion of forests into fynbos. If supported by further work, this facilitative role of Virgilia has management implications for the conservation of fynbos and forests in the Southern Cape of South Africa. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos TI - Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos UR - http://hdl.handle.net/11427/14024 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14024
dc.identifier.vancouvercitationNortje G. Pushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbos. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/14024en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherBiological Sciencesen_ZA
dc.titlePushing the boundaries : Virgilia oroboides (Keurboom) facilitated expansion of forest in to fynbosen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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