Ecological influences in the biogeography of the Austral sedges

 

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dc.contributor.advisor Muasya, A Muthama en_ZA
dc.contributor.advisor Verboom, George Anthony en_ZA
dc.contributor.author Viljoen, Jan-Adriaan en_ZA
dc.date.accessioned 2016-07-11T13:53:14Z
dc.date.available 2016-07-11T13:53:14Z
dc.date.issued 2016 en_ZA
dc.identifier.citation Viljoen, J. 2016. Ecological influences in the biogeography of the Austral sedges. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/20302
dc.description.abstract The biogeographic history of a species is a result of both stochastic processes such as dispersal and habitat filters that determine where a population with a given set of biological requirements can become established. In this dissertation, I examine the geographical and ecological distribution of the sedge tribe Schoeneae in conjunction with its inferred speciation history in order to determine the pattern of dispersal and the environmental factors that have influenced establishment. The biogeographic reconstruction indicates numerous transoceanic dispersal events consistent with random diffusion from an Australian point of origin, but with a bias towards habitats with vegetation type and moisture regime similar to the ancestral conditions of the given subgroup (open and dry habitats in the majority of cases). The global distribution of the tribe also suggests a preference for low-nutrient soils, which I investigate at the local (microhabitat) scale by contrasting the distributions of the tribes Schoeneae and Cypereae on the Cape Peninsula along soil fertility axes. The relationships between the phenotypic traits of species and their soil nutrient levels are also examined to determine whether the coexistence of the two groups in the Cape can be attributed to differences in nutrient accumulation behaviour or strategy of biomass allocation to roots or structural organs vs. leaves. No robust patterns were observed to identify such adaptations or to distinguish the tribes ecologically, a result that is at least partly due to low statistical power in the data set collected, which constrains the analysis to the use of simple models less able to detect subtle patterns in the ecological history of these sedges. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Botany en_ZA
dc.title Ecological influences in the biogeography of the Austral sedges en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Viljoen, J. (2016). <i>Ecological influences in the biogeography of the Austral sedges</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/20302 en_ZA
dc.identifier.chicagocitation Viljoen, Jan-Adriaan. <i>"Ecological influences in the biogeography of the Austral sedges."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2016. http://hdl.handle.net/11427/20302 en_ZA
dc.identifier.vancouvercitation Viljoen J. Ecological influences in the biogeography of the Austral sedges. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2016 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/20302 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Viljoen, Jan-Adriaan AB - The biogeographic history of a species is a result of both stochastic processes such as dispersal and habitat filters that determine where a population with a given set of biological requirements can become established. In this dissertation, I examine the geographical and ecological distribution of the sedge tribe Schoeneae in conjunction with its inferred speciation history in order to determine the pattern of dispersal and the environmental factors that have influenced establishment. The biogeographic reconstruction indicates numerous transoceanic dispersal events consistent with random diffusion from an Australian point of origin, but with a bias towards habitats with vegetation type and moisture regime similar to the ancestral conditions of the given subgroup (open and dry habitats in the majority of cases). The global distribution of the tribe also suggests a preference for low-nutrient soils, which I investigate at the local (microhabitat) scale by contrasting the distributions of the tribes Schoeneae and Cypereae on the Cape Peninsula along soil fertility axes. The relationships between the phenotypic traits of species and their soil nutrient levels are also examined to determine whether the coexistence of the two groups in the Cape can be attributed to differences in nutrient accumulation behaviour or strategy of biomass allocation to roots or structural organs vs. leaves. No robust patterns were observed to identify such adaptations or to distinguish the tribes ecologically, a result that is at least partly due to low statistical power in the data set collected, which constrains the analysis to the use of simple models less able to detect subtle patterns in the ecological history of these sedges. DA - 2016 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - Ecological influences in the biogeography of the Austral sedges TI - Ecological influences in the biogeography of the Austral sedges UR - http://hdl.handle.net/11427/20302 ER - en_ZA


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