Using multi-species seascape genomics to conserve areas of evolutionary importance

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dc.contributor.advisorVon der Heyden, Sophieen_ZA
dc.contributor.advisorHenriques, Rominaen_ZA
dc.contributor.advisorBeger, Mariaen_ZA
dc.contributor.authorNielsen, Erica Spotswooden_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Botany and Zoology.en_ZA
dc.date.accessioned2021-02-01T12:30:06Z
dc.date.accessioned2021-04-21T14:26:54Z
dc.date.available2021-02-01T12:30:06Z
dc.date.available2021-04-21T14:26:54Z
dc.date.issued2021-04
dc.descriptionThesis (PhD)--Stellenbosch University, 2021.en_ZA
dc.description.abstractENGLISH ABSTRACT: Understanding the environmental footprints on species and genetic biodiversity is a key concern in molecular ecology and conservation genetics. As species are increasingly under pressure from anthropogenic climate change, understanding how rapid environmental changes will influence intra- and interspecific diversity is essential if we are to conserve functioning ecosystems. This PhD thesis used the unique environmental backdrop of the South African coastline to infer how environmental variables over space and time shape multiple facets of biological variation. Specifically, this thesis utilised seascape genomic analyses to test the strong environmental gradients within South Africa against the molecular variation of three rocky intertidal species: Cape urchin (Parechinus angulosus), Common shore crab (Cyclograpsus punctatus), and Granular limpet (Scutellastra granularis). The first chapter evaluated which contemporary seascape features most strongly correlate with neutral and adaptive intraspecific diversity across species. Here, the results show that gene-environment relationships are species-specific, with the crab showing less population differentiation, strongly influenced by sea-surface salinity, and the urchin and limpet showing a west-east population differentiation predominantly influenced by sea-surface and air temperature. Chapter Two tested the relative influence of historical climatic stability versus contemporary species distributions in shaping patterns of neutral diversity of the three species. The results from this chapter indicate that historical climatic refugia since the Last Glacial Maximum are potentially stronger predictors of contemporary molecular diversity hotspots than the species’ current distribution. The third research chapter evaluated the vulnerability of the three study species with regards to future climatic change, both at two time-points and under two emission scenarios. Here, the results highlight how future responses to global change will likely differ among species, as well as among populations within each species. In the final chapter, the patterns uncovered in the three data chapters, pertaining to genomic diversity and vulnerability, climatic stability, and adaptive potential, are combined in a conservation planning framework to identify areas of evolutionary importance, which can be thought of as priority areas for forward-thinking conservation action. As a whole, this thesis used novel ecological and evolutionary models to understand the spatio-temporal interplay between species, genes, and environment, and used this information to guide conservation action within South Africa.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.af_ZA
dc.description.versionDoctoralen_ZA
dc.format.extentxviii, 232 pages : illustrations (some color), mapsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/109805
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectConservation genomicsen_ZA
dc.subjectMarine invertebrates -- Effect of human beings onen_ZA
dc.subjectSeascape genomicsen_ZA
dc.subjectBiodiversity conservation -- South africaen_ZA
dc.subjectSpecies distribution modelsen_ZA
dc.subjectAquatic biodiversity conservation -- Effect of climatic changes onen_ZA
dc.subjectUCTDen_ZA
dc.titleUsing multi-species seascape genomics to conserve areas of evolutionary importanceen_ZA
dc.typeThesisen_ZA
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Doctoral Degrees (Botany and Zoology)