The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region

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dc.contributor.advisorWest, Adam G
dc.contributor.advisorHoffman, M Timm
dc.contributor.advisorAltwegg, Res
dc.contributor.authorVan Blerk, Justin J
dc.date.accessioned2021-09-16T10:45:00Z
dc.date.available2021-09-16T10:45:00Z
dc.date.issued2021
dc.date.updated2021-09-16T10:43:23Z
dc.description.abstractShifting climate patterns are a cause for concern for natural ecosystems globally. Of particular concern is the effect of climate change on fire-prone, Mediterranean-type shrublands globally because of the heightened sensitivity of post-fire vegetation to environmental conditions. In this thesis, I focused on investigating the relationships between rainfall seasonality patterns and post-fire vegetation processes in neighbouring Fynbos and Renosterveld shrubland communities within the mega-diverse Cape Floristic Region of South Africa. I investigated vegetation sensitivity to moisture availability at multiple levels of detail including 1) productivity and community structure, 2) growth form responses and 3) physiological performance over three years. Post-fire rainfall patterns were manipulated by artificially increasing summer rainfall and reducing winter rainfall over permanent, field sites, thus reducing annual seasonality and creating soil moisture contrasts between control and treatment plots over warm and cool seasonal periods. At all levels of investigation, postfire vegetation processes at the Fynbos site were relatively insensitive to variations in moisture availability relative to the Renosterveld site where vegetation processes and community structure were strongly affected. Nutrient limitation and lower soil tension in coarse, sandstone-derived soils of the Fynbos site could strongly limit the influence of soil moisture patterns on post-fire physiology leading to stable growth, community structure and productivity under a variety of moisture regimes. Soil moisture patterns during the first summer had significant and long-term implications for community structure and productivity patterns in the Renosterveld site, highlighting the sensitivity of vegetation patterns to early post-fire processes. Overall this study demonstrates that post-fire rainfall patterns can have strong effects on vegetation recovery processes but that structurally similar shrublands, which are specialised to differing soil types, could show marked differences in their response to climate change due to the mediation of climate responses by soils.
dc.identifier.apacitationVan Blerk, J. J. (2021). <i>The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region</i>. (). ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/33950en_ZA
dc.identifier.chicagocitationVan Blerk, Justin J. <i>"The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region."</i> ., ,Faculty of Science ,Department of Biological Sciences, 2021. http://hdl.handle.net/11427/33950en_ZA
dc.identifier.citationVan Blerk, J.J. 2021. The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region. . ,Faculty of Science ,Department of Biological Sciences. http://hdl.handle.net/11427/33950en_ZA
dc.identifier.ris TY - Doctoral Thesis AU - Van Blerk, Justin J AB - Shifting climate patterns are a cause for concern for natural ecosystems globally. Of particular concern is the effect of climate change on fire-prone, Mediterranean-type shrublands globally because of the heightened sensitivity of post-fire vegetation to environmental conditions. In this thesis, I focused on investigating the relationships between rainfall seasonality patterns and post-fire vegetation processes in neighbouring Fynbos and Renosterveld shrubland communities within the mega-diverse Cape Floristic Region of South Africa. I investigated vegetation sensitivity to moisture availability at multiple levels of detail including 1) productivity and community structure, 2) growth form responses and 3) physiological performance over three years. Post-fire rainfall patterns were manipulated by artificially increasing summer rainfall and reducing winter rainfall over permanent, field sites, thus reducing annual seasonality and creating soil moisture contrasts between control and treatment plots over warm and cool seasonal periods. At all levels of investigation, postfire vegetation processes at the Fynbos site were relatively insensitive to variations in moisture availability relative to the Renosterveld site where vegetation processes and community structure were strongly affected. Nutrient limitation and lower soil tension in coarse, sandstone-derived soils of the Fynbos site could strongly limit the influence of soil moisture patterns on post-fire physiology leading to stable growth, community structure and productivity under a variety of moisture regimes. Soil moisture patterns during the first summer had significant and long-term implications for community structure and productivity patterns in the Renosterveld site, highlighting the sensitivity of vegetation patterns to early post-fire processes. Overall this study demonstrates that post-fire rainfall patterns can have strong effects on vegetation recovery processes but that structurally similar shrublands, which are specialised to differing soil types, could show marked differences in their response to climate change due to the mediation of climate responses by soils. DA - 2021 DB - OpenUCT DP - University of Cape Town KW - Biological Sciences LK - https://open.uct.ac.za PY - 2021 T1 - The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region TI - The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region UR - http://hdl.handle.net/11427/33950 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/33950
dc.identifier.vancouvercitationVan Blerk JJ. The effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region. []. ,Faculty of Science ,Department of Biological Sciences, 2021 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/33950en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Biological Sciences
dc.publisher.facultyFaculty of Science
dc.subjectBiological Sciences
dc.titleThe effect of altered rainfall seasonality on post-fire recovery of Fynbos and Renosterveld shrublands in the Cape Floristic Region
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationlevelPhD
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