Département de Biologie, Caribou Ungava, Centre d'Études Nordiques, Université Laval, 1045, Ave. de la Médecine, Québec, QC, G1V 0A6, Canada.
Département de Biologie, Université Laval, Québec, QC, G1V 0A6, Canada.
Oecologia. 2023 Aug;202(4):819-830. doi: 10.1007/s00442-023-05441-7. Epub 2023 Aug 28.
The decline of most caribou (Rangifer tarandus) populations underlines the need to understand the determinants of key demographic parameters. In migratory caribou, we have limited information on rates and drivers of pre-weaning mortality. We fitted 60 pregnant females of the Rivière-aux-Feuilles caribou herd with GPS camera collars to track the survival of calves from birth to weaning in 2016-2018. Over the three years, calf survival rate before weaning, i.e. to 01-Sep, approximately three months of age, was 0.63 (CI 0.50-0.77). Summer mortality risk was mainly influenced by calf birth date, with calves born earlier in the calving season having a lower mortality risk than those born later. Mortality also increased when calves experienced low or high temperature during calving. This study provides the first estimates of pre-weaning survival of migratory caribou calves in this herd, illustrating the value of new technologies to collect data otherwise difficult to obtain in widely distributed migratory populations. This approach can easily be extended to other large herbivores and predators. Our study brings new insights on how climate change may affect summer juvenile survival given the increased temperatures and faster changes in plant phenology expected in the future.
大多数北美驯鹿（Rangifer tarandus）种群的减少凸显了了解关键人口统计参数决定因素的必要性。在迁徙的北美驯鹿中，我们对哺乳期前死亡率的速率和驱动因素的了解有限。我们为 2016 年至 2018 年里里维埃尔-奥克斯-费厄斯驯鹿群的 60 只怀孕母鹿配备了带有 GPS 摄像头的项圈，以追踪小牛从出生到哺乳期结束的存活率。在这三年中，哺乳期前的小牛存活率，即在 9 月 1 日左右，大约三个月大时，为 0.63（置信区间 0.50-0.77）。夏季死亡率的风险主要受小牛出生日期的影响，在产犊季节较早出生的小牛死亡率低于较晚出生的小牛。当小牛在产犊期间经历低温或高温时，死亡率也会增加。本研究首次估算了该鹿群中迁徙北美驯鹿幼仔的哺乳期前存活率，展示了新技术在收集广泛分布的迁徙种群中难以获得的数据方面的价值。这种方法可以很容易地扩展到其他大型食草动物和捕食者。鉴于未来预期的温度升高和植物物候期更快的变化，我们的研究为气候变化如何影响夏季幼体存活率提供了新的见解。
