Crews Storm, Rayl Nathaniel D, Alldredge Mathew W, Bergman Eric J, Anderson Charles R, Bastille-Rousseau Guillaume
Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, IL, 62901, USA.
School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA.
Sci Rep. 2025 Mar 6;15(1):7807. doi: 10.1038/s41598-025-91947-4.
By migrating, ungulates take advantage of cyclical fluctuations in resources, which allows them to persist at greater population numbers than they would in the absence of these seasonal movements. We sought to identify the drivers of spring elk (Cervus canadensis) migration and evaluate how well individuals were able to optimize access to forage prior to departure, while migrating, and upon arrival on summer range. Specifically, we investigated the timing and duration of spring migration in four Colorado elk herds to test how forage quality and snow dynamics pre-, during, and post-migration influenced elk departure from winter range and the length of time spent migrating. Our analyses revealed significant heterogeneity among and within herds. Overall, spatiotemporal dynamics in forage and snow emerged as critical drivers influencing migratory phenology, but the discrete covariates associated with forage and snow were herd-specific. We did not find marked sub-strategies wherein some herds or individuals optimized a specific component of migration, but rather found that elk varied in their ability to optimize access to forage at all times analyzed. Our findings suggest that elk exhibit a flexible response to environmental cues, adjusting migration timing and duration in accordance with local conditions. These results contribute to a deeper understanding of the mechanisms driving ungulate migration and emphasize the importance of considering dynamic environmental factors in studies of migration phenology. Further, they emphasize the importance of forage conditions not just on the migratory route, but also on winter and summer range. Additionally, they provide baseline knowledge of elk migrations in Colorado, useful information for ensuring the conservation and persistence of these migratory routes and the productivity they facilitate.
通过迁徙，有蹄类动物能够利用资源的周期性波动，这使得它们能够维持比不进行这些季节性移动时更多的种群数量。我们试图确定春季麋鹿（加拿大马鹿）迁徙的驱动因素，并评估个体在出发前、迁徙期间以及到达夏季栖息地时获取草料的优化程度。具体而言，我们调查了科罗拉多州四个麋鹿种群春季迁徙的时间和持续时间，以测试迁徙前、迁徙期间和迁徙后的草料质量和积雪动态如何影响麋鹿离开冬季栖息地以及迁徙所花费的时间长度。我们的分析揭示了种群之间和种群内部存在显著的异质性。总体而言，草料和积雪的时空动态成为影响迁徙物候的关键驱动因素，但与草料和积雪相关的离散协变量因种群而异。我们没有发现明显的子策略，即某些种群或个体优化了迁徙的特定组成部分，而是发现麋鹿在所有分析时间获取草料的优化能力各不相同。我们的研究结果表明，麋鹿对环境线索表现出灵活的反应，根据当地条件调整迁徙时间和持续时间。这些结果有助于更深入地理解驱动有蹄类动物迁徙的机制，并强调在迁徙物候研究中考虑动态环境因素的重要性。此外，它们强调了草料条件不仅对迁徙路线，而且对冬季和夏季栖息地的重要性。此外，它们提供了科罗拉多州麋鹿迁徙的基线知识，这对于确保这些迁徙路线及其促进的生产力的保护和持续存在是有用的信息。
