Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Exeter, UK.
Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, UK.
Glob Chang Biol. 2023 Oct;29(19):5596-5614. doi: 10.1111/gcb.16891. Epub 2023 Jul 26.
Climate change is one of the top three global threats to seabirds, particularly species that visit polar regions. Arctic terns migrate between both polar regions annually and rely on productive marine areas to forage, on sea ice for rest and foraging, and prevailing winds during flight. Here, we report 21st-century trends in environmental variables affecting arctic terns at key locations along their Atlantic/Indian Ocean migratory flyway during the non-breeding seasons, identified through tracking data. End-of-century climate change projections were derived from Earth System Models and multi-model means calculated in two Shared Socioeconomic Pathways: 'middle-of-the-road' and 'fossil-fuelled development' scenarios. Declines in North Atlantic primary production emerge as a major impact to arctic terns likely to affect their foraging during the 21st century under a 'fossil-fuelled development' scenario. Minimal changes are, however, projected at three other key regions visited by arctic terns (Benguela Upwelling, Subantarctic Indian Ocean and the Southern Ocean). Southern Ocean sea ice extent is likely to decline, but the magnitude of change and potential impacts on tern survival are uncertain. Small changes (<1 m s ) in winds are projected in both scenarios, but with minimal likely impacts on migration routes and duration. However, Southern Ocean westerlies are likely to strengthen and contract closer to the continent, which may require arctic terns to shift routes or flight strategies. Overall, we find minor effects of climate change on the migration of arctic terns, with the exception of poorer foraging in the North Atlantic. However, given that arctic terns travel over huge spatial scales and live for decades, they integrate minor changes in conditions along their migration routes such that the sum effect may be greater than the parts. Meeting carbon emission targets is vital to slow these end-of-century climatic changes and minimise extinction risk for a suite of polar species.
气候变化是对海鸟的三大全球威胁之一，尤其是那些访问极地地区的物种。北极燕鸥每年在极地之间迁徙，依赖富有生产力的海洋区域觅食、海冰休息和觅食，以及飞行中的盛行风。在这里，我们通过跟踪数据报告了在非繁殖季节影响北极燕鸥的关键位置的环境变量的 21 世纪趋势，这些位置沿着它们的大西洋/印度洋迁徙飞行路线。来自地球系统模型的本世纪末气候变化预测以及在两种共享社会经济途径中计算的多模型平均值：“中间道路”和“化石燃料驱动发展”情景。北大西洋初级生产力的下降成为北极燕鸥的主要影响，可能会影响它们在 21 世纪“化石燃料驱动发展”情景下的觅食。然而，在其他三个北极燕鸥访问的关键地区（本格拉上升流、亚南极印度洋和南大洋），预计变化很小。南大洋海冰范围可能会减少，但变化的幅度及其对燕鸥生存的潜在影响尚不确定。两个情景都预计风速变化较小（<1m/s），但对迁徙路线和持续时间的影响可能很小。然而，南大洋西风可能会加强，并更接近大陆收缩，这可能要求北极燕鸥改变路线或飞行策略。总体而言，我们发现气候变化对北极燕鸥迁徙的影响较小，除了北大西洋觅食条件较差。然而，由于北极燕鸥在巨大的空间尺度上迁徙并生活数十年，它们整合了迁徙路线上条件的微小变化，使得总和效应可能大于部分效应。实现碳排放目标对于减缓本世纪末的气候变化和最小化一系列极地物种的灭绝风险至关重要。
