Intense heat waves are occurring more frequently, with concomitant increases in the risk of catastrophic avian mortality events via lethal dehydration or hyperthermia. We quantified the risks of lethal hyperthermia and dehydration for 10 Australian arid-zone avifauna species during the 21st century, by synthesizing thermal physiology data on evaporative water losses and heat tolerance limits. We evaluated risks of lethal hyperthermia or exceedance of dehydration tolerance limits in the absence of drinking during the hottest part of the day under recent climatic conditions, compared to those predicted for the end of this century across Australia. Increases in mortality risk via lethal dehydration and hyperthermia vary among the species modelled here but will generally increase greatly, particularly in smaller species (~10-42 g) and those inhabiting the far western parts of the continent. By 2100 CE, zebra finches' potential exposure to acute lethal dehydration risk will reach ~ 100 d y-1 in the far northwest of Australia and will exceed 20 d y-1 over > 50% of this species' current range. Risks of dehydration and hyperthermia will remain much lower for large non-passerines such as crested pigeons. Risks of lethal hyperthermia will also increase substantially for smaller species, particularly if they are forced to visit exposed water sources at very high air temperatures to avoid dehydration. An analysis of atlas data for zebra finches suggests that population declines associated with very hot conditions are already occurring in the hottest areas. Our findings suggest that the likelihood of persistence within current species ranges, and the potential for range shifts, will become increasingly constrained by temperature and access to drinking water. Our model adds to an increasing body of literature suggesting that arid environments globally will experience considerable losses of avifauna and biodiversity under unmitigated climate change scenarios.

中文翻译：

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在 21 世纪干旱的澳大利亚，热浪期间的禽类死亡风险将大大增加。

强烈的热浪更频繁地发生，伴随着致命的脱水或高热导致灾难性禽类死亡事件的风险增加。我们通过综合蒸发水分损失和耐热极限的热生理学数据，量化了 21 世纪 10 种澳大利亚干旱区鸟类的致命高温和脱水风险。我们评估了在最近的气候条件下，在一天中最热的时候没有饮酒的致命高温或超过脱水耐受极限的风险，与澳大利亚本世纪末预测的风险相比。因致命脱水和体温过高而增加的死亡风险在此处建模的物种之间有所不同，但通常会大大增加，特别是在较小的物种（~10-42 g）和居住在大陆西部的那些。到公元 2100 年，斑胸草雀在澳大利亚最西北部面临急性致命脱水风险的潜在风险将达到约 100 年 1 年，并将超过 20 年 1 年，超过该物种当前活动范围的 50% 以上。对于像凤头鸽这样的大型非雀形目动物来说，脱水和体温过高的风险将大大降低。对于较小的物种，致命的高热风险也将大大增加，特别是如果它们被迫在非常高的气温下访问暴露的水源以避免脱水。对斑胸草雀的地图集数据的分析表明，与非常热的条件相关的种群下降已经发生在最热的地区。我们的研究结果表明，在当前物种范围内持续存在的可能性以及范围变化的可能性将越来越受到温度和饮用水的限制。我们的模型增加了越来越多的文献表明，在未经缓解的气候变化情景下，全球干旱环境将经历相当大的鸟类动物和生物多样性损失。