Gangloff Eric J, Sorlin Mahaut, Cordero Gerardo A, Souchet Jérémie, Aubret Fabien
Physiol Biochem Zool. 2019 Mar/Apr;92(2):189-200. doi: 10.1086/701793.
Warming climates are facilitating the range expansion of many taxa to habitats that were formerly thermally inhospitable, including to higher latitudes and elevations. The potential for such colonization, however, varies widely among taxa. Because environmental factors may interact to affect colonization potential, an understanding of underlying physiological and behavioral mechanisms is necessary to predict how species will respond to potentially suitable habitats. For example, temperature and oxygen availability will interact to shape physiological and performance traits. Our model species, the wall lizard, Podarcis muralis, is a widely distributed ectotherm that continues to expand its range in Europe despite being limited by cold temperatures at high elevations and latitudes. To test the potential for organisms to expand to warming high-altitude environments, we conducted a transplant experiment to quantify the within-individual effects of high-altitude hypoxia on physiological and performance traits. Transplanted lizards maintained individual differences in physiological traits related to oxygen capacity and metabolism (hemoglobin concentration, hematocrit, and peak postexhaustion metabolic rate), as well as performance traits tied to fitness (sprint speed and running endurance). Although lizards altered blood biochemistry to increase oxygen-carrying capacity, their performance was reduced at high altitude. Furthermore, lizards at high altitude suffered a rapid loss of body condition over the 6-wk experiment, suggesting an energetic cost to hypoxia. Taken together, this demonstrates a limited potential for within-individual plasticity to facilitate colonization of novel high-altitude environments.
气候变暖正促使许多生物分类群向以前因温度不适宜而无法栖息的生境扩张，包括向更高的纬度和海拔地区。然而，这种定殖的潜力在不同分类群之间差异很大。由于环境因素可能相互作用影响定殖潜力，因此有必要了解潜在的生理和行为机制，以便预测物种将如何应对潜在适宜的生境。例如，温度和氧气供应将相互作用塑造生理和性能特征。我们的模式物种——壁蜥（Podarcis muralis）是一种分布广泛的变温动物，尽管在高海拔和高纬度地区受到低温限制，但它在欧洲的分布范围仍在不断扩大。为了测试生物体向变暖的高海拔环境扩张的潜力，我们进行了一项移植实验，以量化高海拔低氧对生理和性能特征的个体内影响。移植的蜥蜴在与氧气容量和代谢相关的生理特征（血红蛋白浓度、血细胞比容和力竭后峰值代谢率）以及与适应性相关的性能特征（冲刺速度和跑步耐力）方面保持个体差异。尽管蜥蜴改变了血液生化组成以增加携氧能力，但它们在高海拔地区的性能仍有所下降。此外，在为期6周的实验中，高海拔地区的蜥蜴身体状况迅速下降，这表明低氧会带来能量消耗。综上所述，这表明个体内可塑性促进新的高海拔环境定殖的潜力有限。
