Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient.
Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient.
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DOI：
10.1002/ece3.2929
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发表时间：
2017-05
影响因子：
2.6
通讯作者：
Moritz C
中科院分区：
文献类型：
--
作者：
von May R;Catenazzi A;Corl A;Santa-Cruz R;Carnaval AC;Moritz C
临界热极限被认为与生活在热带山区的物种的海拔分布有关，但与下限相比，上限相对不变。为了验证这一假设，我们研究了沿热带海拔梯度分布的一组陆生繁殖蛙（Craugastoridae）的热生理性状的变化。我们测量了在亚马逊河漫滩（海拔250米）和安第斯山脉高海拔（海拔3800米）之间捕获的青蛙的临界热最大值（CT max, n = 22种）和临界热最小值（CT min, n = 14种）。在推断出一个多位点物种树后，我们进行了一个系统发育方面的测试，以确定身体大小、体重和海拔是否影响了观察到的CT max和CT min沿梯度的变化。我们还测试了CT最大值和CT最小值是否表现出不同的变化率，因为临界热极限（及其塑性）可能随着梯度的不同温度约束而发生不同的演变。关键热性状的变化与海拔中点、最高海拔和最低海拔、最高气温和最高工作温度呈显著相关。在其他类群中，两个热极限都有较大的变化，但最小热极限的变化速度比最大热极限快。尽管如此，我们的研究结果要求在假设热上限不灵活时要谨慎，并强调收集跨海拔梯度物种热生理的额外经验数据的价值。
Critical thermal limits are thought to be correlated with the elevational distribution of species living in tropical montane regions, but with upper limits being relatively invariant compared to lower limits. To test this hypothesis, we examined the variation of thermal physiological traits in a group of terrestrial breeding frogs (Craugastoridae) distributed along a tropical elevational gradient. We measured the critical thermal maximum (CT max; n = 22 species) and critical thermal minimum (CT min; n = 14 species) of frogs captured between the Amazon floodplain (250 m asl) and the high Andes (3,800 m asl). After inferring a multilocus species tree, we conducted a phylogenetically informed test of whether body size, body mass, and elevation contributed to the observed variation in CT max and CT min along the gradient. We also tested whether CT max and CT min exhibit different rates of change given that critical thermal limits (and their plasticity) may have evolved differently in response to different temperature constraints along the gradient. Variation of critical thermal traits was significantly correlated with species’ elevational midpoint, their maximum and minimum elevations, as well as the maximum air temperature and the maximum operative temperature as measured across this gradient. Both thermal limits showed substantial variation, but CT min exhibited relatively faster rates of change than CT max, as observed in other taxa. Nonetheless, our findings call for caution in assuming inflexibility of upper thermal limits and underscore the value of collecting additional empirical data on species’ thermal physiology across elevational gradients.