EAGER: Climatic influences on migratory fidelity

动物如何应对气候变化是生态学中的一个核心和有争议的问题。这个项目将研究阿拉斯加北部驯鹿脱落的鹿角如何揭示在过去几十年和几个世纪里，随着气候的变化，雌性驯鹿分娩的地点（它们的“产犊地”）发生了多大的变化。这是可能的，因为雌性每年都会长出鹿角，并在分娩后几天内脱落，而且脱落的鹿角不会分解。它们保存了几个世纪，可以被发现、收集和分析，以揭示它们是什么时候脱落的。研究人员将把这些信息与每只雌性大熊猫分娩时的气候记录联系起来。鹿角还能揭示迁徙的模式。关键的一点是，这种简单的方法允许人们在与自然气候周期相匹配的时间尺度上测量气候的影响。有许多假设的复杂模型是不必要的。这项工作通过提供数据来帮助管理北美驯鹿的数量，从而使社会受益。该研究员将促进美国和加拿大科学家、管理人员和政策制定者之间的交流。最后，该项目将支持面向北极保护区附近Gwich'in土著民族一个村庄的学龄学生以及俄亥俄州辛辛那提市的小学生、大学生和研究生的外联和培训活动。本项目使用从沿海平原豪猪驯鹿群（北极保护区）的产犊地取样的雌性鹿角来确定产犊地的地理分布如何随着时间的推移而变化。中心假设是，与繁殖有关的景观利用（即产犊地）的变异性受到气候的强烈影响。对于每只鹿角，将使用放射性碳定年法和时间校准的骨衰变状态相结合的方法来估计脱落日期。在十年至百年的时间尺度上，产犊地地理分布的变化将与北极涛动的记录配对，以测试气候对迁徙保真度的作用，并评估当前气候轨迹对未来长距离（驯鹿）迁徙的影响。本研究的目的是：(1)建立一个确定未知北美驯鹿鹿角性别的全鹿角模型；(2)建立北极骨骼风化的阶段和速率；(3)量化气候对北美驯鹿产犊地地理变异性的影响。更广泛地说，这项工作将突出骨骼积累作为种群生物学年代际到百年尺度数据的来源，这是一种具有潜力的资源，可以极大地扩大研究种群和群落生态学的许多方面的时间尺度。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

How animals may respond to climate change is a central and controversial issue in ecology. This project will examine how antlers shed by caribou in northern Alaska can reveal how much females have changed the location of where they give birth (their “calving grounds”) as climate has shifted over decades and centuries. This is made possible by the simple facts that females grow antlers every year and shed them within days of giving birth and that the shed antlers do not break down. Lasting for centuries, they can be found, collected and analyzed to reveal when they were shed. The researcher will link that information with separate records of climate at the time each female gave birth. The antlers can also reveal patterns of migration. The key point is that this simple approach allows one to measure the influence of climate across time scales that match those of natural climate cycles. Complicated models with many assumptions are unnecessary. This work benefits society by providing data to help manage caribou populations. The researcher will foster communication between scientists, managers, and policy makers in the USA and Canada. Finally, the project will support outreach and training activities for school-aged students in a village of the Gwich'in Indigenous Nation near the Arctic Refuge, as well as primary school, college, and graduate students in Cincinnati, Ohio.This project uses shed female caribou antlers sampled from the Coastal Plain calving grounds of the Porcupine Caribou Herd (Arctic Refuge) to identify how the geographic distribution of calving grounds has changed through time. The central hypothesis is that variability in reproductively-tied landscape use (i.e., calving grounds) is strongly influenced by climate. For each antler, date-of-shed will be estimated using a combination of radiocarbon dating and time-calibrated states of bone decay. Changes in the geographic distribution of calving grounds across decadal- to centennial-timescales will be paired with records of the Arctic Oscillation to test the roles of climate on migratory fidelity and to evaluate impacts of current climate trajectories on future long-distance (caribou) migration. The aims of this research are to (1) establish a whole-antler model for determining sex of unknown caribou antlers, (2) establish the stages and rates of arctic bone weathering, and (3) quantify the climatic influences on the geographic variability of caribou calving grounds. More broadly, this work will highlight bone accumulations as sources of decadal- to centennial-scale data on population biology -- a resource with potential to dramatically expand the timescales with which many aspects of population and community ecology are studied.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.