Rising temperatures and more intense heatwaves pose a grave risk to birds which call Australia’s arid zone home, says Dr Lynda Sharpe of the Australian National University (ANU).
To predict how global warming and intensifying heatwaves will impact upon arid zone birds, researchers have developed models based on the physiological responses of captive birds to high temperatures. These models predict that catastrophic mortality events will become more frequent under future climate scenarios, particularly within Australia, but it remains unclear whether the lab-based findings apply to wild populations.
A wild jacky winter exhibiting symptoms of dehydration after a heatwave (image courtesy of Janet Gardner)
To quantify the impacts of heat exposure on wild populations, and validate the models, the team of researchers from ANU’s Division of Ecology and Evolution has assessed the effects that extreme heat has on a wild population of jacky winters (Microeca fascinans)—a small grey-brown robin, common throughout much of Australia.
Every day during a series of severe heatwaves in the summer of 2018-19, they monitored the change in the weight of individual jacky winters. Conducting their research at TERN’s Calperum Mallee SuperSite in South Australia, Dr Sharpe and her colleagues compared the body mass data with the micro-meteorological data collected by the site’s eddy-covariance flux tower.
A wild jacky winter perched on a balance for weighing (image courtesy of Janet Gardner)
Despite the team’s frightful findings, the research seems to have a silver lining. Fellow researcher Dr Janet Gardner says that the daily weight losses they recorded in the field were less than the lab-based models predicted.
Although the study documents the effects of extreme heat on just one population of a single species, the research results suggest that wild birds may be less severely affected, and more able to recuperate, than anticipated. Research is ongoing…
A wild jacky winter engaging in heat dissipation behaviour (image courtesy of Janet Gardner)
Data on the exchanges of energy, carbon and water between the ground and atmosphere, as well as detailed soil and vegetation data, have been collected at TERN’s Calperum Mallee SuperSite (above) since 2012 and are openly available via TERN
Published in TERN newsletter January 2020