Longhini Leonardo S, Zena Lucas A, Polymeropoulos Elias T, Rocha Aline C G, da Silva Leandro Gabriela, Prado Cynthia P A, Bícego Kênia C, Gargaglioni Luciane H
Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil.
Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
Front Physiol. 2021 Oct 8;12:726440. doi: 10.3389/fphys.2021.726440. eCollection 2021.
Amphibians may be more vulnerable to climate-driven habitat modification because of their complex life cycle dependence on land and water. Considering the current rate of global warming, it is critical to identify the vulnerability of a species by assessing its potential to acclimate to warming temperatures. In many species, thermal acclimation provides a reversible physiological adjustment in response to temperature changes, conferring resilience in a changing climate. Here, we investigate the effects of temperature acclimation on the physiological performance of tadpoles of a stream-breeding savanna tree frog () in relation to the thermal conditions naturally experienced in their microhabitat (range: 18.8-24.6°C). We quantified performance measures such as routine and maximum metabolic rate at different test (15, 20, 25, 30, and 34°C) and acclimation temperatures (18 and 25°C). We also measured heart rate before and after autonomic blockade with atropine and sotalol at the respective acclimation temperatures. Further, we determined the critical thermal maximum and warming tolerance (critical thermal maximum minus maximum microhabitat temperature), which were not affected by acclimation. Mass-specific routine and mass-specific maximum metabolic rate, as well as heart rate, increased with increasing test temperatures; however, acclimation elevated mass-specific routine metabolic rate while not affecting mass-specific maximum metabolic rate. Heart rate before and after the pharmacological blockade was also unaffected by acclimation. Aerobic scope in animals acclimated to 25°C was substantially reduced, suggesting that physiological performance at the highest temperatures experienced in their natural habitat is compromised. In conclusion, the data suggest that the tadpoles of , living in a thermally stable environment, have a limited capacity to physiologically adjust to the highest temperatures found in their micro-habitat, making the species more vulnerable to future climate change.
由于两栖动物复杂的生命周期依赖于陆地和水，它们可能更容易受到气候驱动的栖息地改变的影响。考虑到当前全球变暖的速度，通过评估一个物种适应温度升高的潜力来确定其脆弱性至关重要。在许多物种中，热适应提供了一种可逆的生理调节以应对温度变化，从而在不断变化的气候中赋予恢复力。在这里，我们研究了温度适应对一种在溪流中繁殖的稀树草原树蛙蝌蚪生理性能的影响，这与它们微生境中自然经历的热条件（范围：18.8 - 24.6°C）有关。我们量化了不同测试温度（15、20、25、30和34°C）和适应温度（18和25°C）下的性能指标，如常规代谢率和最大代谢率。我们还在各自的适应温度下，用阿托品和索他洛尔进行自主神经阻滞前后测量了心率。此外，我们确定了临界热最大值和热耐受性（临界热最大值减去最大微生境温度），它们不受适应的影响。质量特异性常规代谢率和质量特异性最大代谢率以及心率随测试温度升高而增加；然而，适应提高了质量特异性常规代谢率，同时不影响质量特异性最大代谢率。药理学阻滞前后的心率也不受适应的影响。适应25°C的动物的有氧范围大幅降低，这表明它们在自然栖息地经历的最高温度下的生理性能受到了损害。总之，数据表明，生活在热稳定环境中的该树蛙蝌蚪在生理上适应其微生境中发现的最高温度的能力有限，这使得该物种更容易受到未来气候变化的影响。
