Neubauer Philipp, Andersen Ken H
Dragonfly Data Science, Level 4, 158 Victoria St., Stephenson & Turner House Te Aro, Wellington New Zealand.
Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark, 7 Kemitorvet B 202, Kongens Lyngby, Denmark.
Conserv Physiol. 2019 Jun 10;7(1):coz025. doi: 10.1093/conphys/coz025. eCollection 2019.
Increasing temperatures under climate change are thought to affect individual physiology of fish and other ectotherms through increases in metabolic demands, leading to changes in species performance with concomitant effects on species ecology. Although intuitively appealing, the driving mechanism behind thermal performance is contested; thermal performance (e.g. growth) appears correlated with metabolic scope (i.e. oxygen availability for activity) for a number of species, but a substantial number of datasets do not support oxygen limitation of long-term performance. Whether or not oxygen limitations via the metabolic scope, or a lack thereof, have major ecological consequences remains a highly contested question. size and trait-based model of energy and oxygen budgets to determine the relative influence of metabolic rates, oxygen limitation and environmental conditions on ectotherm performance. We show that oxygen limitation is not necessary to explain performance variation with temperature. Oxygen can drastically limit performance and fitness, especially at temperature extremes, but changes in thermal performance are primarily driven by the interplay between changing metabolic rates and species ecology. Furthermore, our model reveals that fitness trends with temperature can oppose trends in growth, suggesting a potential explanation for the paradox that species often occur at lower temperatures than their growth optimum. Our model provides a mechanistic underpinning that can provide general and realistic predictions about temperature impacts on the performance of fish and other ectotherms and function as a null model for contrasting temperature impacts on species with different metabolic and ecological traits.
气候变化导致的气温上升被认为会通过增加代谢需求来影响鱼类和其他变温动物的个体生理机能，进而导致物种表现发生变化，并对物种生态产生相应影响。尽管这一观点直观上很有吸引力，但热性能背后的驱动机制仍存在争议；许多物种的热性能（如生长）似乎与代谢范围（即活动所需的氧气供应）相关，但大量数据集并不支持长期性能受氧气限制这一观点。通过代谢范围产生的氧气限制是否会产生重大生态后果，仍是一个备受争议的问题。我们构建了基于大小和性状的能量与氧气预算模型，以确定代谢率、氧气限制和环境条件对变温动物性能的相对影响。我们发现，用氧气限制来解释性能随温度的变化并非必要。氧气会严重限制性能和适应性，尤其是在极端温度下，但热性能的变化主要是由代谢率变化与物种生态之间的相互作用驱动的。此外，我们的模型表明，适应性随温度的变化趋势可能与生长趋势相反，这为物种通常出现在低于其生长最适温度的悖论提供了一种潜在解释。我们的模型提供了一种机制基础，能够对温度对鱼类和其他变温动物性能的影响做出一般且现实的预测，并作为一个零模型，用于对比温度对具有不同代谢和生态特征的物种的影响。
