Data from: Many places called home: the adaptive value of seasonal adjustments in range fidelity

1. The vast majority of animal species display range fidelity, a space-use behaviour enhancing familiarity with local habitat features. While the fitness benefits of this behaviour have been demonstrated in a variety of taxa, some species or populations rather display infidelity, displacing their home range over time. Others, such as many ungulate species, show seasonal adjustments in their range fidelity to accommodate changes in the dominance of limiting factors or in the distribution of resources. 2. Few empirical studies have explored the adaptive value of seasonal adjustments in range fidelity. Using boreal populations of woodland caribou (Rangifer tarandus caribou) as a biological model, we evaluated how range fidelity impacted individual performance during two seasons where juvenile and adult survival are limited by different predation pressures. 3. Between 2004 and 2013, we monitored the survival, reproductive success, habitat selection and range fidelity of female caribou in the boreal forest of eastern Canada. Using resource selection functions, we assessed how seasonal range fidelity was linked to two fitness correlates: calf survival in summer and adult female survival in winter. 4. Females displayed season-specific space use tactics: they selected previously used areas during calving and summer, but tended to shift their winter range from one year to the next. During calving and summer, range fidelity yielded relatively high fitness benefits, as females that did not lose their calf displayed stronger fidelity than females that did. In winter, however, adult survival was negatively linked to range fidelity, as females that survived selected areas further away from their seasonal range of the previous year than females that died. 5. We provide one of the first evidences that making seasonal adjustments in range fidelity can be an adaptive behaviour influencing the spatial distribution of a threatened species. Assessing the seasonal nature of range fidelity tactics may improve our predictions of space use and associated fitness implications for species displaying this behaviour.

1. 绝大多数动物类群均表现出活动范围保真（range fidelity）行为，这是一种可提升对本地生境特征熟悉程度的空间利用策略。尽管该行为的适合度益处已在多个类群中得到证实，但部分物种或种群反而表现出活动范围偏离，随时间推移改变其家域（home range）。另有部分类群，如多数有蹄类动物，会调整其活动范围保真行为的季节性模式，以应对限制性因子主导地位的变化或资源分布的变动。
2. 鲜有实证研究探讨活动范围保真行为季节性调整的适应价值。本研究以寒温带森林的林地驯鹿（Rangifer tarandus caribou）种群作为生物学模型，评估了在两个因不同捕食压力分别限制幼体与成体存活率的季节中，活动范围保真对个体生存表现的影响。
3. 2004年至2013年间，我们对加拿大东部寒温带森林中的雌性驯鹿的存活率、繁殖成功率、生境选择以及活动范围保真行为进行了监测。通过资源选择函数（resource selection functions），我们分析了季节性活动范围保真与两项适合度相关指标的关联：夏季幼鹿存活率与冬季成年雌性驯鹿存活率。
4. 雌性驯鹿表现出季节特异性的空间利用策略：在产仔季与夏季，它们会选择过往曾利用的区域，但冬季家域往往会在年际间发生偏移。在产仔季与夏季，活动范围保真可带来相对较高的适合度益处——成功抚育幼鹿的雌性个体的活动范围保真程度高于幼鹿死亡的雌性个体。而在冬季，成年存活率与活动范围保真呈负相关：存活的雌性个体所选择区域相较于前一年季节性家域的距离，远大于死亡的雌性个体。
5. 本研究首次证实，对活动范围保真行为进行季节性调整，可作为一种适应性行为影响受威胁物种的空间分布格局。评估活动范围保真策略的季节性特征，有助于提升我们对表现出该行为的物种的空间利用模式及其相关适合度效应的预测能力。