Seasonality in light becomes increasingly extreme at high latitudes, both in terms of the diel light–dark cycle and the duration of light summers and dark winters. In contrast to temperature, this latitudinal gradient in light seasonality is not affected by climate change. A key question is therefore whether light may act as a fixed constraint on warming-driven redistributions of organisms at high latitudes. One answer is provided by studying mechanistic models of visual foraging and temperature-driven physiology along latitudinal gradients to project where populations survive and acquire resources to reproduce, and where they demise. Here we contrast such models for two widespread planktivorous fish types. We identify two processes through which seasonality in light can act as a barrier to poleward range expansions at high latitudes: (1) longer dark winters lead to greater depletion of overwinter energy stores and (2) a longer duration of midnight sun entails higher foraging-related predation mortality.

在高纬度地区，光照的季节性变得越来越极端，无论是在昼夜明暗循环还是光夏和冬夜的持续时间方面。与温度相比，这种光照季节性的纬度梯度不受气候变化的影响。因此，一个关键问题是光是否可以成为高纬度地区由变暖驱动的生物重新分布的固定约束。一个答案是通过研究视觉觅食的机械模型和沿纬度梯度的温度驱动生理学来预测种群在哪里生存和获得资源以进行繁殖，以及它们在哪里消亡。在这里，我们将此类模型用于两种广泛的浮游鱼类类型。我们确定了两个过程，通过这些过程，光照的季节性可以成为高纬度向极地范围扩展的障碍：