Migration is a prevalent strategy among birds used to track seasonal resources throughout the year. Individual and population-level migratory movements provide insight to life-history variation, carry-over effects, and impacts of climate change. Our understanding of how geographic variation in a species' breeding or wintering grounds can impact migration distances is limited. However, changes in migration distances can have important fitness consequences for individuals and conservation implications for populations, particularly if migratory connectivity is altered during the annual cycle. In this study, we use three decades of data from the United States Geological Survey Bird Banding Laboratory for six migratory species of Arctic and subarctic breeding geese. We employ a Bayesian hierarchical framework to test if the distance between breeding and wintering locations has changed over time, while accounting for the latitude of the breeding grounds. A model that included only a temporal trend estimated the average rate of change in migration distance, across all six species, at −3.0 km/year over the period 1990–2019. Five of the six species showed a significant decrease in migration distances. Including an interaction effect with breeding latitude revealed that the reduction in migration distance was strongest in the southernmost populations for four of the six species. For those species, migration distance in northern populations were all either relatively unchanged or increasing. This indicates that southern breeding populations of geese had a stronger association with the observed spatiotemporal changes in wintering ranges, potentially influenced by a combination of climatic and biotic factors (e.g. resource availability or competitive interactions) that uniquely impact these populations. Abundant, long-term banding data shows promise for use in illuminating changes in migratory patterns under climate change, leading to improved management and conservation outcomes, from regional to continental scales.

中文翻译：

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南方繁殖种群导致北极和亚北极雁的迁徙距离缩短


迁徙是鸟类用来追踪全年季节性资源的普遍策略。个人和人口层面的迁徙运动提供了对生活史变异、遗留效应和气候变化影响的洞察。我们对物种繁殖地或越冬地的地理变化如何影响迁徙距离的了解是有限的。然而，迁徙距离的变化可能会对个体的健康产生重要的影响，并对种群的保护产生影响，特别是如果迁徙的连通性在年度周期中发生变化的话。在这项研究中，我们使用了美国地质调查局鸟类环志实验室三十年来针对北极和亚北极繁殖雁的六种迁徙物种的数据。我们采用贝叶斯分层框架来测试繁殖地和越冬地点之间的距离是否随时间变化，同时考虑繁殖地的纬度。仅包含时间趋势的模型估计，1990年至2019年期间，所有六个物种的迁徙距离平均变化率为-3.0公里/年。六个物种中有五个的迁徙距离显着缩短。包括与繁殖纬度的相互作用效应表明，六个物种中的四个物种的迁徙距离的缩短在最南端的种群中最为明显。对于这些物种来说，北方种群的迁徙距离要么相对不变，要么有所增加。这表明南方鹅的繁殖种群与观察到的越冬范围的时空变化有更强的相关性，可能受到气候和生物因素（例如，气候）的综合影响。 资源可用性或竞争性互动）对这些人群产生独特的影响。丰富的长期条带数据显示出有望用于阐明气候变化下迁徙模式的变化，从而改善从区域到大陆尺度的管理和保护成果。