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. 绝大多数动物类群都表现出活动范围忠实性（range fidelity）——这是一种可提升对本地栖息地特征熟悉程度的空间利用行为。尽管该行为的适合度收益已在多个类群中得到证实，但部分物种或种群却会表现出活动范围背离行为，随时间推移改变自身家域（home range）。另有类群，如多数有蹄类动物，会对活动范围忠实性进行季节性调整，以适配限制因子主导地位或资源分布的变化。 2. 目前针对活动范围忠实性的季节性调整的适应价值，相关实证研究尚属少见。本研究以北美林地驯鹿（Rangifer tarandus caribou）的北方种群为生物模型，探究了在幼体与成体存活率受不同捕食压力限制的两个季节中，活动范围忠实性如何影响个体表现。 3. 2004年至2013年间，我们对加拿大东部北方森林中的雌性驯鹿的存活率、繁殖成功率、栖息地选择及活动范围忠实性进行了追踪监测。本研究借助资源选择函数（resource selection functions），评估了季节性活动范围忠实性与两项适合度相关指标的关联：夏季幼崽存活率与冬季雌性成体存活率。 4. 雌性驯鹿展现出特定季节的空间利用策略：在产犊期与夏季，它们会选择过往曾使用的区域，但冬季家域往往会在年际间发生转移。在产犊期与夏季，活动范围忠实性可带来较高的适合度收益，成功育幼的雌性个体的活动范围忠实性要强于幼崽死亡的个体。然而在冬季，成体存活率与活动范围忠实性呈负相关：存活个体选择的区域，相较于死亡个体，距上一年度的季节性家域更远。 5. 本研究提供了首批实证证据之一，证实对活动范围忠实性进行季节性调整，是一种可影响受威胁物种空间分布的适应性行为。评估活动范围忠实性策略的季节性特征，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相关适合度影响的预测能力。