Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history

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dc.contributor.authorCunningham, Susan Jen_ZA
dc.contributor.authorKruger, Andries Cen_ZA
dc.contributor.authorNxumalo, Mthobisi Pen_ZA
dc.contributor.authorHockey, Philip A Ren_ZA
dc.date.accessioned2015-11-16T04:10:58Z
dc.date.available2015-11-16T04:10:58Z
dc.date.issued2013en_ZA
dc.description.abstractIncreases in the frequency, duration and intensity of heat waves are frequently evoked in climate change predictions. However, there is no universal definition of a heat wave. Recent, intense hot weather events have caused mass mortalities of birds, bats and even humans, making the definition and prediction of heat wave events that have the potential to impact populations of different species an urgent priority. One possible technique for defining biologically meaningful heat waves is to use threshold temperatures (T thresh ) above which known fitness costs are incurred by species of interest. We set out to test the utility of this technique using T thresh values that, when exceeded, affect aspects of the fitness of two focal southern African bird species: the southern pied babbler Turdiodes bicolor (T thresh = 35.5°C) and the common fiscal Lanius collaris (T thresh = 33°C). We used these T thresh values to analyse trends in the frequency, duration and intensity of heat waves of magnitude relevant to the focal species, as well as the annual number of hot days (maximum air temperature > T thresh ), in north-western South Africa between 1961 and 2010. Using this technique, we were able to show that, while all heat wave indices increased during the study period, most rapid increases for both species were in the annual number of hot days and in the maximum intensity (and therefore intensity variance) of biologically meaningful heat waves. Importantly, we also showed that warming trends were not uniform across the study area and that geographical patterns in warming allowed both areas of high risk and potential climate refugia to be identified. We discuss the implications of the trends we found for our focal species, and the utility of the T thresh technique as a conservation tool.en_ZA
dc.identifier.apacitationCunningham, S. J., Kruger, A. C., Nxumalo, M. P., & Hockey, P. A. R. (2013). Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history. <i>PLoS One</i>, http://hdl.handle.net/11427/15017en_ZA
dc.identifier.chicagocitationCunningham, Susan J, Andries C Kruger, Mthobisi P Nxumalo, and Philip A R Hockey "Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history." <i>PLoS One</i> (2013) http://hdl.handle.net/11427/15017en_ZA
dc.identifier.citationCunningham, S. J., Kruger, A. C., Nxumalo, M. P., & Hockey, P. A. (2012). Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history. PloS one, 8(12), e82492-e82492. doi:10.1371/journal.pone.0082492en_ZA
dc.identifier.ris TY - Journal Article AU - Cunningham, Susan J AU - Kruger, Andries C AU - Nxumalo, Mthobisi P AU - Hockey, Philip A R AB - Increases in the frequency, duration and intensity of heat waves are frequently evoked in climate change predictions. However, there is no universal definition of a heat wave. Recent, intense hot weather events have caused mass mortalities of birds, bats and even humans, making the definition and prediction of heat wave events that have the potential to impact populations of different species an urgent priority. One possible technique for defining biologically meaningful heat waves is to use threshold temperatures (T thresh ) above which known fitness costs are incurred by species of interest. We set out to test the utility of this technique using T thresh values that, when exceeded, affect aspects of the fitness of two focal southern African bird species: the southern pied babbler Turdiodes bicolor (T thresh = 35.5°C) and the common fiscal Lanius collaris (T thresh = 33°C). We used these T thresh values to analyse trends in the frequency, duration and intensity of heat waves of magnitude relevant to the focal species, as well as the annual number of hot days (maximum air temperature > T thresh ), in north-western South Africa between 1961 and 2010. Using this technique, we were able to show that, while all heat wave indices increased during the study period, most rapid increases for both species were in the annual number of hot days and in the maximum intensity (and therefore intensity variance) of biologically meaningful heat waves. Importantly, we also showed that warming trends were not uniform across the study area and that geographical patterns in warming allowed both areas of high risk and potential climate refugia to be identified. We discuss the implications of the trends we found for our focal species, and the utility of the T thresh technique as a conservation tool. DA - 2013 DB - OpenUCT DO - 10.1371/journal.pone.0082492 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history TI - Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history UR - http://hdl.handle.net/11427/15017 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15017
dc.identifier.urihttp://dx.doi.org/10.1371/journal.pone.0082492
dc.identifier.vancouvercitationCunningham SJ, Kruger AC, Nxumalo MP, Hockey PAR. Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history. PLoS One. 2013; http://hdl.handle.net/11427/15017.en_ZA
dc.language.isoengen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_ZA
dc.rights.holder© 2013 Cunningham et alen_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourcePLoS Oneen_ZA
dc.source.urihttp://journals.plos.org/plosoneen_ZA
dc.subject.otherWeather stationsen_ZA
dc.subject.otherBirdsen_ZA
dc.subject.otherClimate changeen_ZA
dc.subject.otherWave frequencyen_ZA
dc.subject.otherBird physiologyen_ZA
dc.subject.otherSpecies delimitationen_ZA
dc.titleIdentifying biologically meaningful hot-weather events using threshold temperatures that affect life-historyen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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