In North America, winters are becoming more variable such that warm and cold extremes are increasingly common. Refugia (in time or space) can reduce the exposure animals experience to extreme temperatures. However, animals must be able to adjust their behavior to capitalize on refugia. Our goal was to identify the behavioral mechanisms that grant access to refugia in time and space, focusing on a northern ungulate (white-tailed deer, Odocoileus virginianus) as a model. We drew upon an extensive camera trap network in Wisconsin, USA, over two winters that experienced both warm and cold extremes. To understand the use of temporal refugia, we modeled deer activity (at daily resolution) during night, dawn, day, and dusk as a function of weather predictors. To understand the use of spatial refugia, we modeled deer activity at camera locations (at daily resolution) as a function of landscape characteristics, weather conditions, and landscape–weather interactions. During anomalously cold temperatures, deer became more diurnal; conversely, on anomalously warm days, deer were more nocturnal. Deer were more active in conifer-dominated landscapes on cold days. Conversely, during warm extremes, deer increased activity in deciduous-dominated landscapes. Finally, deer showed multiple modes of behavioral flexibility (activity in time as well as space) and demonstrated stronger responses to temperature anomalies later in the winter, suggesting that the effects of extreme events are dependent upon their seasonal timing. Behavioral shifts presumably reduce exposure to extremes and may render species more resilient to increasingly variable winter climates.

中文翻译：

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行为灵活性有助于在多变的冬季天气中使用空间和时间避难所

在北美，冬天变得越来越多变，以至于极端温暖和寒冷的天气越来越普遍。避难所（在时间或空间上）可以减少动物暴露在极端温度下的经历。然而，动物必须能够调整自己的行为以利用避难所。我们的目标是确定允许在时间和空间上进入避难所的行为机制，重点关注北方有蹄类动物（白尾鹿，Odocoileus virginianus）作为模型。我们利用美国威斯康星州的一个广泛的相机陷阱网络，在经历了极端温暖和寒冷的两个冬天。为了了解临时避难所的使用，我们将夜间、黎明、白天和黄昏期间的鹿活动（以每日分辨率）建模为天气预报的函数。要了解空间避难所的使用，我们根据景观特征、天气条件和景观-天气相互作用对相机位置（以每日分辨率）的鹿活动进行建模。在异常寒冷的温度下，鹿变得更加昼夜；相反，在异常温暖的日子里，鹿更喜欢夜间活动。在寒冷的日子里，鹿在针叶树为主的景观中更加活跃。相反，在温暖的极端情况下，鹿在落叶树为主的景观中增加了活动。最后，鹿表现出多种行为灵活性模式（时间和空间活动），并在冬季晚些时候表现出对温度异常的更强反应，这表明极端事件的影响取决于它们的季节性时间。