Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa

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dc.contributor.advisorCook, Timothéeen_ZA
dc.contributor.advisorSherley, Richarden_ZA
dc.contributor.advisorRyan, Peter Gen_ZA
dc.contributor.authorCampbell, Greg Thomasen_ZA
dc.date.accessioned2015-05-18T14:21:38Z
dc.date.available2015-05-18T14:21:38Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractClimate change continues to cause rising air and sea surface temperatures and changes in precipitation patterns across the globe. Many seabirds will be challenged by increasing temperatures because they must balance conflicting adaptations for dealing with cold environments when foraging and hot environments when nesting. Heat stressed seabirds often gular flutter for thermoregulation, a behaviour that is effective for dissipating heat but expensive in terms of evaporative water loss. This study examined gular fluttering behaviour of four species of southern African cormorants, crowned ( Microcarbo coronatus ), Cape ( Phalacrocorax capensis ), bank ( Phalacrocorax neglectus ), and white-breasted ( Phalacrocorax carbolucidus) cormorants. Results show that gular fluttering is influenced by temperature, body position and body size. Gular fluttering increases with temperature and larger cormorant species spend a greater proportion of time gular fluttering for a given temperature. Threshold temperatures for initiating gular fluttering are lower for large than for small cormorant species. Proportions of time spent gular fluttering are higher when birds are sitting than when crouching over the nest. Water loss shows the same pattern as gular fluttering, with the larger species estimated to lose a higher percentage of their daily water intake. Larger cormorant species can lose as much as 40% of their daily ingested water after eight hours of gular fluttering. These findings indicate that temperature increases from climate change will likely have serious direct impacts on nesting cormorant colonies in southern Africa. Gular fluttering could increase by as much as 25% by 2100 under current projected temperature increases, and increases in water loss could reach nearly 10%. Some species may shift their breeding dates to compensate for increasing temperatures, but if breeding activities are timed to coincide with peaks in their main prey specie s, this may result in poorer diets or increased competition from other species.en_ZA
dc.identifier.apacitationCampbell, G. T. (2014). <i>Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology. Retrieved from http://hdl.handle.net/11427/12815en_ZA
dc.identifier.chicagocitationCampbell, Greg Thomas. <i>"Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2014. http://hdl.handle.net/11427/12815en_ZA
dc.identifier.citationCampbell, G. 2014. Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Campbell, Greg Thomas AB - Climate change continues to cause rising air and sea surface temperatures and changes in precipitation patterns across the globe. Many seabirds will be challenged by increasing temperatures because they must balance conflicting adaptations for dealing with cold environments when foraging and hot environments when nesting. Heat stressed seabirds often gular flutter for thermoregulation, a behaviour that is effective for dissipating heat but expensive in terms of evaporative water loss. This study examined gular fluttering behaviour of four species of southern African cormorants, crowned ( Microcarbo coronatus ), Cape ( Phalacrocorax capensis ), bank ( Phalacrocorax neglectus ), and white-breasted ( Phalacrocorax carbolucidus) cormorants. Results show that gular fluttering is influenced by temperature, body position and body size. Gular fluttering increases with temperature and larger cormorant species spend a greater proportion of time gular fluttering for a given temperature. Threshold temperatures for initiating gular fluttering are lower for large than for small cormorant species. Proportions of time spent gular fluttering are higher when birds are sitting than when crouching over the nest. Water loss shows the same pattern as gular fluttering, with the larger species estimated to lose a higher percentage of their daily water intake. Larger cormorant species can lose as much as 40% of their daily ingested water after eight hours of gular fluttering. These findings indicate that temperature increases from climate change will likely have serious direct impacts on nesting cormorant colonies in southern Africa. Gular fluttering could increase by as much as 25% by 2100 under current projected temperature increases, and increases in water loss could reach nearly 10%. Some species may shift their breeding dates to compensate for increasing temperatures, but if breeding activities are timed to coincide with peaks in their main prey specie s, this may result in poorer diets or increased competition from other species. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa TI - Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa UR - http://hdl.handle.net/11427/12815 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/12815
dc.identifier.vancouvercitationCampbell GT. Effects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/12815en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherConservation Biologyen_ZA
dc.titleEffects of temperature on gular fluttering and evaporative water loss in four sympatric cormorants in southern Africaen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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