Will climate warming exceed lethal photosynthetic temperature thresholds of lichens in a southern African arid region?

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dc.contributor.authorMaphangwa, Khumbudzo Walter
dc.contributor.authorMusil, Charles F.
dc.contributor.authorRaitt, Lincoln
dc.contributor.authorZedda, Luciana
dc.date.accessioned2017-07-13T13:56:59Z
dc.date.available2017-07-13T13:56:59Z
dc.date.issued2013
dc.description.abstractPredicted elevated temperatures and a shift from a winter to summer rainfall pattern associated with global warming could result in the exposure of hydrated lichens during summer to more numerous temperature extremes that exceed their thermal thresholds. This hypothesis was tested by measuring lethal temperature thresholds under laboratory and natural conditions for four epilithic lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta) occurring on quartz gravel substrates at a hot arid inland site two epigeous lichen species (Teloschistes capensis, Ramalina sp.) occurring on gypsum-rich topsoil at a warm humid coastal site. Extrapolated lethal temperatures for photosynthetic quantum yield under laboratory conditions were up to 4°C higher for lichens from a dry inland site than those from a humid coastal site. Lethal temperatures extrapolated for photosynthetic quantum yield at a saturating photosynthetic photon flux density of ≥11,000 µmol photons m-2s-1 under natural conditions were up to 6°C higher for lichens from the dry inland site than the more humid coastal site. It is concluded that only under atypical conditions of lichen exposure in a hydrated state to temperature extremes at high midday solar irradiances during summer could lethal photosynthetic thresholds in sensitive lichen species be potentially exceeded, but whether the increased frequency of such conditions with climate warming would lead to increased likelihood of lichen mortality is debatable.en_US
dc.description.accreditationWeb of Science
dc.identifier.citationMaphangwa, K. W. et al. (2013). Will climate warming exceed lethal photosynthetic temperature thresholds of lichens in a southern African arid region? African Journal of Ecology, 52: 228 - 236en_US
dc.identifier.issn0141-6607
dc.identifier.urihttp://hdl.handle.net/10566/3073
dc.identifier.urihttp://dx.doi.org/10.1111/aje.12110
dc.language.isoenen_US
dc.privacy.showsubmitterFALSE
dc.publisherWileyen_US
dc.rightsThis is the author-version of the article published online at: http://dx.doi.org./10.1111/aje.12110
dc.status.ispeerreviewedTRUE
dc.subjectArid ecosystemen_US
dc.subjectClimate warmingen_US
dc.subjectLethal photosynthetic temperaturesen_US
dc.subjectLichensen_US
dc.subjectSouth Africaen_US
dc.subjectSucculenten_US
dc.subjectKarooen_US
dc.subjectBiomeen_US
dc.titleWill climate warming exceed lethal photosynthetic temperature thresholds of lichens in a southern African arid region?en_US
dc.typeArticleen_US

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Prof. Lincoln Raitt