School of Life and Environmental Sciences A08, University of Sydney, Sydney, New South Wales, Australia.
School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia.
Ecol Lett. 2024 Sep;27(9):e14511. doi: 10.1111/ele.14511.
Climate change is altering temperature means and variation, and both need to be considered in predictions underpinning conservation. However, there is no consensus in the literature regarding the effects of temperature fluctuations on biological functions. Fluctuations may affect biological responses because of inequalities from non-linear responses, endocrine regulation or exposure to damaging temperatures. Here we establish the current state of knowledge of how temperature fluctuations impact biological responses within individuals and populations compared to constant temperatures with the same mean. We conducted a meta-analysis of 143 studies on ectothermic animals (1492 effect sizes, 118 species). In this study, 89% of effect sizes were derived from diel cycles, but there were no significant differences between diel cycles and shorter (<8 h) or longer (>48 h) cycles in their effect on biological responses. We show that temperature fluctuations have little effect overall on trait mean and variance. Nonetheless, temperature fluctuations can be stressful: fluctuations increased 'gene expression' in aquatic animals, which was driven mainly by increased hsp70. Fluctuating temperatures also decreased longevity, and increased amplitudes had negative effects on population responses in aquatic organisms. We conclude that mean temperatures and extreme events such as heat waves are important to consider, but regular (particularly diel) temperature fluctuations are less so.
气候变化正在改变温度均值和变化幅度，在支持保护的预测中，这两者都需要被考虑。然而，关于温度波动对生物功能的影响，文献中尚未达成共识。波动可能会影响生物反应，因为非线性反应、内分泌调节或暴露于有害温度导致不平等。在这里，我们通过比较恒温下的个体和种群的生物反应，来确定目前关于温度波动如何影响生物反应的知识状态。我们对 143 项关于变温动物的研究进行了荟萃分析（1492 个效应量，118 个物种）。在这项研究中，89%的效应量来自昼夜节律，但昼夜节律与较短（<8 小时）或较长（>48 小时）周期对生物反应的影响之间没有显著差异。我们表明，温度波动对性状均值和方差的总体影响很小。尽管如此，温度波动可能是有压力的：波动增加了水生动物的“基因表达”，这主要是由 hsp70 的增加驱动的。波动的温度也降低了寿命，并且在水生生物中，增加的幅度对种群反应有负面影响。我们的结论是，平均温度和极端事件（如热浪）很重要，但定期（特别是昼夜）的温度波动则不那么重要。
