Complex life cycle and biphasic range expansion in plants.

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dc.contributor.advisorHui, Cangen_ZA
dc.contributor.advisorRodger, Jamesen_ZA
dc.contributor.advisorLatombe, Guillaumeen_ZA
dc.contributor.advisorLandi, Pietroen_ZA
dc.contributor.authorRobertson, Tremaineen_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Mathematical Sciences.en_ZA
dc.date.accessioned2020-02-06T08:27:11Z
dc.date.accessioned2020-04-28T15:10:36Z
dc.date.available2020-02-06T08:27:11Z
dc.date.available2020-04-28T15:10:36Z
dc.date.issued2020-03
dc.descriptionThesis (MSc)--Stellenbosch University, 2021.en_ZA
dc.description.abstractENGLISH ABSTRACT: The rate of the spread of populations into new habitat has been extensively studied. In particular, the long-term spread rate of plant populations has been analytically formulated in terms of the travelling wave solution. However, plants often display a biphasic range expansion, where a long-term fast spread phase is preceded by a slower spread phase. This has been explained by fattailed dispersal kernels, habitat transition or stratified diffusion. Nonetheless, since pollen production and dispersal are integral parts of the plant life cycle, they might play a role in the spread patterns of plants. For these reasons, I included pollen production and dispersal, in addition to seed production and dispersal, in an integrodifference equation (IDE model of plant spread in continuous space and discrete-time. The numerical results showed that biphasic range expansions are produced by considering the complex life cycle of plants. Furthermore, I observed that seed dispersal increased both the slow and fast phases of the biphasic range expansion. Pollen dispersal had constrained the velocity of the slow phase, but drove the velocity of the fast phase. However, when pollen dispersal is much higher than seed dispersal, a boom-and-bust phenomenon is observed, indicating that the velocity of spread decreases and the population declines and eventually goes extinct as few plants are located at far distances to be pollinated. These results shed new light on the importance of different life stages and dispersal events in driving biphasic range expansions of plant populations.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMMING: Die tempo van die verspreiding van bevolkings na 'n nuwe habitat is breedvoerig bestudeer. In die besonder is die langtermynverspreidingsyfer van plantpopulasies analities geformuleer in terme van die bewegende golfoplossing. Plante vertoon egter dikwels 'n tweefase-uitbreiding, waar 'n langtermynverspreidingsfase voorafgegaan word deur 'n stadiger verspreidingsfase. Dit word verklaar deur vetstert waarskynlikheidsverdelings, habitatoorgang of gestrati- seerde di usie. Aangesien stuifmeelproduksie en verspreiding integrale dele van die plantlewensiklus is, speel dit egter 'n rol in die verspreidingspatrone van plante. Om hierdie redes het ek stuifmeelproduksie en verspreiding, benewens saadproduksie en verspreiding, ook in 'n model met 'n integraaldi erensiaalvergelyking (IDV van plantverspreiding in kontinue ruimte en diskrete tyd ingesluit. Die numeriese resultate het getoon dat die uitbreiding van tweefasige omvang geproduseer word deur die ingewikkelde lewensiklus van plante. Verder het ek opgemerk dat verspreiding van saad 'n positiewe uitwerking op beide die stadige en vinnige fases van die uitbreiding van die bifasiese reeks het. Stuifmeelverspreiding het 'n negatiewe uitwerking op die snelheid van die stadige fase, maar 'n positiewe invloed op die snelheid van die vinnige fase. Wanneer die stuifmeelverspreiding egter veel hoer is as die verspreiding van saad, word 'n styg-en-daal verskynsel waargeneem, wat aandui dat die verspreidingsnelheid daal en die bevolking daal en uiteindelik uitsterf. Hierdie resultate werp nuwe lig op die belangrikheid van verskillende lewensfases en verspreidingsgebeurtenisse in die bevordering van die uitbreiding van plantegroei in tweefase.af_ZA
dc.description.versionMastersen_ZA
dc.embargo.terms2020-12-31
dc.format.extentviii, 44 pagesen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/108350
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectBiphasic range expansionen_ZA
dc.subjectLife cycles (Biology)en_ZA
dc.subjectPollen -- Dispersal -- Mathematical modelsen_ZA
dc.subjectIntroduced organisms -- Spread -- Mathematical modelsen_ZA
dc.subjectUCTD
dc.titleComplex life cycle and biphasic range expansion in plants.en_ZA
dc.typeThesisen_ZA
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