Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography

 

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dc.contributor.advisor Hoffman, Timm en_ZA
dc.contributor.advisor Jack , Sam en_ZA
dc.contributor.advisor February, Edmund C en_ZA
dc.contributor.author White, Joseph Douglas Mandla en_ZA
dc.date.accessioned 2015-09-15T10:33:16Z
dc.date.available 2015-09-15T10:33:16Z
dc.date.issued 2013 en_ZA
dc.identifier.citation White, J. 2013. Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/14029
dc.description.abstract Repeat photography photosets were used to analyse 20th century changes in populations of Widdringtonia cedarbergensis from four sites in the Cederberg Mountains, South Africa. Systematic evaluation of 115 photosets was combined with field observation and environmental data to determine the age class and degree of foliage cover, as well as fire frequency, rockiness of habitat, altitude, aspect of slope, annual mean temperature and annual precipitation for each tree viewed in photosets. Mortality and recruitment events were documented in each of the photosets. A total of 1315 trees were recorded in historical photographs (1931- 1982), with 968 of these shown to have died in the repeat photographs (2007-2013), indicating 74% mortality. With only 45 (3.4%) recruits being recorded, the total current living population of W. cedarbergensis in the repeat photographs was 392. There was no significant difference found in mortality or recruitment across the sampled sites. From the historical to repeat photosets there was an 8% increase in the proportion of mature adults and a 13% increase in the proportion of W. cedarbergensis individuals with sparse foliage cover. A generalized linear model was used to determine the effects of environmental factors on W. cedarbergensis mortality in natural populations. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Biological Sciences en_ZA
dc.title Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography en_ZA
dc.type Bachelor 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 Honours
dc.type.qualificationname BSc (Hons) en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation White, J. D. M. (2013). <i>Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/14029 en_ZA
dc.identifier.chicagocitation White, Joseph Douglas Mandla. <i>"Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013. http://hdl.handle.net/11427/14029 en_ZA
dc.identifier.vancouvercitation White JDM. Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/14029 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - White, Joseph Douglas Mandla AB - Repeat photography photosets were used to analyse 20th century changes in populations of Widdringtonia cedarbergensis from four sites in the Cederberg Mountains, South Africa. Systematic evaluation of 115 photosets was combined with field observation and environmental data to determine the age class and degree of foliage cover, as well as fire frequency, rockiness of habitat, altitude, aspect of slope, annual mean temperature and annual precipitation for each tree viewed in photosets. Mortality and recruitment events were documented in each of the photosets. A total of 1315 trees were recorded in historical photographs (1931- 1982), with 968 of these shown to have died in the repeat photographs (2007-2013), indicating 74% mortality. With only 45 (3.4%) recruits being recorded, the total current living population of W. cedarbergensis in the repeat photographs was 392. There was no significant difference found in mortality or recruitment across the sampled sites. From the historical to repeat photosets there was an 8% increase in the proportion of mature adults and a 13% increase in the proportion of W. cedarbergensis individuals with sparse foliage cover. A generalized linear model was used to determine the effects of environmental factors on W. cedarbergensis mortality in natural populations. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography TI - Analysis of long-term changes in populations of the Clanwiliam Cedar (Widdringtonia cedarbergensis) using repeat photography UR - http://hdl.handle.net/11427/14029 ER - en_ZA


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