Kirkland Máire, Annorbah Nathaniel N D, Barber Lee, Black John, Blackburn Jeremy, Colley Michael, Clewley Gary, Cross Colin, Drew Mike, Fox Oliver J L, Gilson Vicky, Hahn Steffen, Holt Chas, Hulme Mark F, Jarjou John, Jatta Dembo, Jatta Emmanuel, Leighton Kevin, Mensah-Pebi Ernestina, Orsman Chris, Sarr Naffie, Walsh Roger, Zwarts Leo, Fuller Robert J, Atkinson Philip W, Hewson Chris M
British Trust for Ornithology, The Nunnery, Thetford, Norfolk, IP24 2PU, UK.
Ghana Wildlife Society, Accra Conservation Education Centre, Independence Avenue, 078-8918, Ridge, Ghana.
Sci Rep. 2025 Jan 26;15(1):3307. doi: 10.1038/s41598-025-86484-z.
Understanding the distribution of breeding populations of migratory animals in the non-breeding period (migratory connectivity) is important for understanding their response to environmental change. High connectivity (low non-breeding population dispersion) may lower resilience to climate change and increase vulnerability to habitat loss within their range. Very high levels of connectivity are reportedly rare, but this conclusion may be limited by methodology. Using multiple tracking methods, we demonstrate extremely high connectivity in a strongly declining, peripheral breeding population of a long-distance migrant, the Common Nightingale in the UK. Non-breeding population dispersion is lower than for previously tracked populations of this and other species and likely lower than can usually be detected by light-level geolocation, the main tracking method for small bodied species. Extremely low levels of population mixing were also detected, so any impacts on this population on the non-breeding grounds are unlikely to be shared with more distant breeding populations, corresponding to the observed patterns of European population change. According to a species distribution model using independent field data, this population's non-breeding grounds had lower suitability than others and likely declined before the period we were able to assess. These results support hypotheses that climatic and habitat-related deterioration of non-breeding grounds contributes to population declines in peripheral and high-connectivity breeding populations of long-distance migrants, including the one studied here.
了解迁徙动物繁殖种群在非繁殖期的分布情况（迁徙连通性）对于理解它们对环境变化的反应至关重要。高连通性（低非繁殖种群分散度）可能会降低对气候变化的恢复力，并增加其在分布范围内对栖息地丧失的脆弱性。据报道，极高的连通性情况很少见，但这一结论可能受到方法学的限制。我们使用多种追踪方法，证明了在英国一种远距离迁徙鸟类——歌鸲数量急剧下降的边缘繁殖种群中存在极高的连通性。其非繁殖种群的分散度低于此前追踪的该物种及其他物种的种群，而且可能低于通常通过小型物种主要追踪方法——光定位所能检测到的水平。我们还检测到种群混合程度极低，因此在非繁殖地对该种群的任何影响不太可能与距离更远的繁殖种群共享，这与欧洲种群变化的观测模式相符。根据一个使用独立野外数据的物种分布模型，该种群的非繁殖地适宜性低于其他地区，并且可能在我们能够评估的时期之前就已经退化。这些结果支持了以下假设：非繁殖地与气候和栖息地相关的退化导致了远距离迁徙鸟类边缘和高连通性繁殖种群数量下降，包括此处研究的种群。
