School of Molecular and Life Sciences, Curtin University, Perth, Western Australia 3102, Australia
Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
J Exp Biol. 2020 Jun 17;223(Pt 12):jeb225524. doi: 10.1242/jeb.225524.
Desert birds inhabit hot, dry environments that are becoming hotter and drier as a consequence of climate change. Extreme weather such as heatwaves can cause mass-mortality events that may significantly impact populations and species. There are currently insufficient data concerning physiological plasticity to inform models of species' response to extreme events and develop mitigation strategies. Consequently, we examine here the physiological plasticity of a small desert bird in response to hot (mean maximum ambient temperature=42.7°C) and cooler (mean maximum ambient temperature=31.4°C) periods during a single Austral summer. We measured body mass, metabolic rate, evaporative water loss and body temperature, along with blood parameters (corticosterone, glucose and uric acid) of wild zebra finches () to assess their physiological state and determine the mechanisms by which they respond to heatwaves. Hot days were not significant stressors; they did not result in modification of baseline blood parameters or an inability to maintain body mass, provided drinking water was available. During heatwaves, finches shifted their thermoneutral zone to higher temperatures. They reduced metabolic heat production, evaporative water loss and wet thermal conductance, and increased hyperthermia, especially when exposed to high ambient temperature. A consideration of the significant physiological plasticity that we have demonstrated to achieve more favourable heat and water balance is essential for effectively modelling and planning for the impacts of climate change on biodiversity.
沙漠鸟类栖息在炎热、干燥的环境中，由于气候变化，这些环境变得越来越炎热和干燥。极端天气，如热浪，可能导致大量死亡事件，这可能会对种群和物种产生重大影响。目前关于生理可塑性的数据还不够充分，无法为物种对极端事件的反应模型提供信息，也无法制定缓解策略。因此，我们在这里研究了一种小型沙漠鸟类在一个澳大利亚夏季的炎热（平均最高环境温度=42.7°C）和凉爽（平均最高环境温度=31.4°C）时期的生理可塑性。我们测量了野生斑胸草雀（）的体重、代谢率、蒸发失水和体温，以及血液参数（皮质酮、葡萄糖和尿酸），以评估它们的生理状态，并确定它们应对热浪的反应机制。炎热的天气并不是显著的应激源；只要有饮用水，它们就不会导致基线血液参数的改变，也不会导致体重无法维持。在热浪期间，雀类将其等热区转移到更高的温度。它们减少了代谢产热、蒸发失水和湿热传导，并增加了体温过高，尤其是在暴露于高环境温度时。考虑到我们已经证明的显著的生理可塑性，以实现更有利的热和水平衡，对于有效地模拟和规划气候变化对生物多样性的影响至关重要。
