Data from: Coping with strong variations in winter severity: plastic habitat selection of deer at high density

Few empirical studies on large herbivores considered how behavioral plasticity could enhance their capacity to cope with rapid and extreme changes in weather conditions at several spatiotemporal scales. During winter, large herbivores living under low predation pressure mainly trade-off benefits of forage acquisition with the costs of exposure to harsh weather conditions. We assessed the changes in this trade-off for white-tailed deer adult females on Anticosti Island (Canada) at different scales during 2 contrasted winters (i.e., a harsher and a milder winter). We hypothesized that deer should adjust their foraging decisions to avoid cold wind-chill temperatures and high locomotion costs in deep snow as winter severity increased. We compared habitat selection at the home-range scale, habitat selection relative to thermal conditions within the home range, and selection for foraging sites relative to snow conditions along the foraging tracks between winters. Home-range selection of deer was similar between winters. Deer adjusted their within-home-range selection relative to thermal conditions: they selected thermal cover during cold-stress periods while their selection for open areas increased during the warmer periods. Deer showed high behavioral plasticity along their foraging tracks: they selected tracks with different forage resources between winters and traded-off the locomotion costs in deep snow cover with the benefits of forage availability as winter severity increased. We discuss how behavioral plasticity of deer in their thermoregulatory behavior and foraging site selection allows them to cope with varying winter conditions, in a system where their short-term behavioral adaptations were already strongly constrained by intraspecific competition.目前鲜有针对大型植食动物（large herbivores）的实证研究，探讨其行为可塑性（behavioral plasticity）如何提升其在多时空尺度下应对快速极端天气变化的能力。冬季时，处于低捕食压力环境中的大型植食动物，主要会在获取食物的收益与暴露于恶劣天气的代价之间进行权衡。本研究以加拿大安蒂科斯蒂岛的成年雌性白尾鹿（white-tailed deer）为研究对象，在两个差异显著的冬季（即极寒冬季与暖冬）中，从多尺度评估了这类权衡关系的变化。我们提出研究假设：随着冬季严酷程度上升，白尾鹿会调整觅食决策，以规避风寒低温与深雪环境下高昂的移动成本。我们对比了两个冬季间，白尾鹿在家域尺度（home-range scale）的生境选择、家域内基于热环境的生境选择，以及沿觅食路径基于积雪条件的觅食位点选择。两个冬季中，白尾鹿的家域选择并无显著差异；它们会根据热环境条件调整家域内的生境选择：在冷应激时段，它们会选择热遮蔽（thermal cover），而在较温暖的时段则更倾向于选择开阔区域。白尾鹿在觅食路径上表现出极强的行为可塑性：两个冬季间，它们会选择具备不同食物资源的路径，且随着冬季严酷程度上升，会在深雪环境下的移动成本与食物可获取性带来的收益之间进行权衡。最后，我们探讨了白尾鹿的体温调节行为与觅食位点选择的行为可塑性，如何帮助其应对动态变化的冬季环境——而在此研究系统中，它们的短期行为适应已受到种内竞争（intraspecific competition）的强烈制约。