MARBEC, University of Montpellier, CNRS, IFREMER, IRD, Montpellier, France.
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
J Fish Biol. 2021 Jun;98(6):1536-1555. doi: 10.1111/jfb.14620. Epub 2020 Dec 19.
Intraspecific variation in key traits such as tolerance of warming can have profound effects on ecological and evolutionary processes, notably responses to climate change. The empirical evidence for three primary elements of intraspecific variation in tolerance of warming in fishes is reviewed. The first is purely mechanistic that tolerance varies across life stages and as fishes become mature. The limited evidence indicates strongly that this is the case, possibly because of universal physiological principles. The second is intraspecific variation that is because of phenotypic plasticity, also a mechanistic phenomenon that buffers individuals' sensitivity to negative impacts of global warming in their lifetime, or to some extent through epigenetic effects over successive generations. Although the evidence for plasticity in tolerance to warming is extensive, more work is required to understand underlying mechanisms and to reveal whether there are general patterns. The third element is intraspecific variation based on heritable genetic differences in tolerance, which underlies local adaptation and may define long-term adaptability of a species in the face of ongoing global change. There is clear evidence of local adaptation and some evidence of heritability of tolerance to warming, but the knowledge base is limited with detailed information for only a few model or emblematic species. There is also strong evidence of structured variation in tolerance of warming within species, which may have ecological and evolutionary significance irrespective of whether it reflects plasticity or adaptation. Although the overwhelming consensus is that having broader intraspecific variation in tolerance should reduce species vulnerability to impacts of global warming, there are no sufficient data on fishes to provide insights into particular mechanisms by which this may occur.
种内变异，如对变暖的耐受能力等关键特征，可能对生态和进化过程产生深远影响，尤其是对气候变化的响应。本文综述了鱼类对变暖的耐受能力的种内变异的三个主要要素的经验证据。第一个是纯粹的机制性的，即耐受能力在不同的生命阶段和鱼类成熟时发生变化。有限的证据强烈表明，这是因为存在普遍的生理原则。第二个是由于表型可塑性而产生的种内变异，这也是一种机制现象，可以缓冲个体在其一生中对全球变暖的负面影响的敏感性，或者在一定程度上通过连续几代的表观遗传效应来缓冲。尽管对变暖的耐受能力的可塑性证据广泛存在，但仍需要更多的工作来理解潜在机制，并揭示是否存在普遍模式。第三个要素是基于对变暖的耐受能力的遗传差异的种内变异，这是本地适应性的基础，可能决定了一个物种在持续的全球变化面前的长期适应性。有明确的本地适应性证据和对变暖耐受能力的遗传力的一些证据，但知识库有限，只有少数模型或标志性物种有详细信息。种内对变暖的耐受能力也存在着明显的结构变异，这可能具有生态和进化意义，无论它是否反映了可塑性还是适应性。尽管人们普遍认为，具有更广泛的种内耐受能力应该会降低物种对全球变暖影响的脆弱性，但鱼类的相关数据还不足以深入了解这可能发生的具体机制。
