Department of Zoology, The University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, Canada V6T 1Z4.
Integr Comp Biol. 2013 Oct;53(4):648-59. doi: 10.1093/icb/ict066. Epub 2013 Jun 19.
Anthropogenic environmental change is exposing animals to changes in a complex array of interacting stressors and is already having important effects on the distribution and abundance of species. However, despite extensive examination of the effects of stressors in isolation, knowledge of the effects of stressors in combination is limited. This lack of information makes predicting the responses of organisms to anthropogenic environmental change challenging. Here, we focus on the effects of temperature and hypoxia as interacting stressors in fishes. A review of the available evidence suggests that temperature and hypoxia act synergistically such that small shifts in one stressor could result in large effects on organismal performance when a fish is exposed to the 2 stressors in combination. Although these stressors pose substantial challenges for fish, there also is substantial intraspecific variation in tolerance to these stressors that could act as the raw material for the evolution of improved tolerance. However, the potential for adaptive change is, in part, dependent on the nature of the correlations among traits associated with tolerance. For example, negative genetic correlations (or trade-offs) between tolerances to temperature and hypoxia could limit the potential for adaptation to the combined stressors, while positive genetic correlations might be of benefit. The limited data currently available suggest that tolerances to hypoxia and to high-temperature may be positively correlated in some species of fish, suggesting the possibility for adaptive evolution in these traits in response to anthropogenic environmental change.
人为造成的环境变化使动物面临着一系列相互作用的压力源的变化，这已经对物种的分布和丰度产生了重要影响。然而，尽管人们广泛研究了单独的压力源的影响，但对复合压力源的影响的了解是有限的。这种信息的缺乏使得预测生物体对人为环境变化的反应具有挑战性。在这里，我们关注温度和缺氧作为鱼类相互作用的压力源的影响。对现有证据的回顾表明，温度和缺氧具有协同作用，以至于当鱼类同时暴露在这两种压力源下时，一个压力源的微小变化可能导致对生物体性能的巨大影响。尽管这些压力源对鱼类构成了巨大的挑战，但鱼类对这些压力源的耐受性也存在着相当大的种内变异，这可能成为提高耐受性进化的原始材料。然而，适应性变化的潜力在一定程度上取决于与耐受性相关的性状之间的相关性的性质。例如，对温度和缺氧的耐受性之间的负遗传相关（或权衡）可能会限制对复合压力源的适应潜力，而正遗传相关可能会受益。目前可用的有限数据表明，在一些鱼类物种中，对缺氧和高温的耐受性可能呈正相关，这表明这些性状可能会对人为环境变化产生适应性进化。
