Verhille Christine E, MacDonald Michael, Noble Ben, Demorest Gavin, Roche Alzada, Frazier Kayleigh, Albertson Lindsey K
Department of Ecology, Montana State University, Bozeman, MT 59717, USA.
Conserv Physiol. 2024 Jul 5;12(1):coae043. doi: 10.1093/conphys/coae043. eCollection 2024.
Warming of aquatic ecosystems is transforming the distribution, phenology and growth of the organisms dependent upon these ecosystems. Aquatic insects such as stoneflies are especially vulnerable to warming because the aquatic nymph stage of their life cycle depends on cool, well-oxygenated, flowing water habitat. We tracked thermal effects on available aerobic capacity of the aquatic nymph stage of an iconic and vulnerable stonefly species, the giant salmonfly (), to compare habitat thermal regime measurements for two salmonfly populations from habitats separated by a gradient in summer weekly maximum temperatures. Contrary to expectations, the thermal optima range of the warmer habitat population was cooler than for the cooler habitat population. We posit that this unexpected interpopulation variation in thermal response is more strongly driven by diel and seasonal thermal variability than by the highest summer temperatures experienced within respective habitats. Additionally, we show that summer daily maximum temperatures could result in periodic limits in available aerobic capacity to support work of the warmer habitat nymphs and may be the mechanism underlying reduced abundance relative to the upstream cooler habitat population. Our findings provide insight into potential thermal and metabolic mechanisms that could regulate the success of ecological and culturally important aquatic insect species experiencing global change. We conclude that thermal regimes and thermal variation, not just mean and maximum temperatures, are critical drivers of aquatic insect responses to water temperatures.
水生生态系统的变暖正在改变依赖这些生态系统的生物的分布、物候和生长。诸如石蝇之类的水生昆虫尤其容易受到变暖的影响，因为它们生命周期中的水生若虫阶段依赖于凉爽、富含氧气的流水栖息地。我们追踪了对一种标志性且易受影响的石蝇物种——巨型鲑鱼石蝇（）水生若虫阶段有氧能力的热效应，以比较来自夏季每周最高温度存在梯度差异的栖息地的两个鲑鱼石蝇种群的栖息地热状况测量值。与预期相反，较温暖栖息地种群的热最适范围比凉爽栖息地种群的更凉爽。我们认为，这种热反应中种群间的意外差异更多是由昼夜和季节性热变化驱动的，而非各自栖息地所经历的夏季最高温度。此外，我们表明夏季每日最高温度可能会导致支持较温暖栖息地若虫活动的有氧能力出现周期性限制，这可能是相对于上游凉爽栖息地种群数量减少的潜在机制。我们的研究结果为潜在的热和代谢机制提供了见解，这些机制可能会调节经历全球变化的具有生态和文化重要性的水生昆虫物种的生存情况。我们得出结论，热状况和热变化，而非仅仅是平均温度和最高温度，是水生昆虫对水温反应的关键驱动因素。
