The increasing pressure of anthropogenic development in areas with high natural value poses a huge challenge for wildlife conservation worldwide. The Tagus estuary in southern Portugal is among the most important wetlands for migratory shorebirds in the East Atlantic Flyway (EAF). However, in 2020 the Portuguese government approved the construction of the new Lisbon international airport at the heart of the Tagus estuary. Intense aircraft traffic, flying at low altitudes during both approach and take-off, is expected to cross the estuary, overlapping to a great extent the important intertidal foraging areas. Here, we aim to quantify the potential loss of conservation value of the intertidal areas of the Tagus estuary for shorebirds resulting from the disturbance (noise) caused by overflying aircraft. Using a comprehensive dataset of wintering shorebird abundance and distribution in the whole intertidal estuarine area we first identified priority areas for conservation using a spatial prioritization approach. We then performed a replacement cost analysis by excluding the areas likely to become unsuitable or severely underused by birds due to intense air traffic noise. Our results suggest that the implementation of the new Lisbon airport may lead to a loss of up to 30% of the conservation value of the Tagus estuary in terms of intertidal feeding areas of wintering birds alone. The global impact will likely be greater when effects on supratidal roosts, as well as on passage birds, are also considered. The Tagus estuary, which is internationally important for six of the 10 species included in our analysis, is just one of a network of already depleted sites along the EAF. Thus, negative impacts on bird populations on the Tagus estuary will have repercussions and undermine conservation efforts elsewhere. The plight of shorebirds at the Tagus estuary is thus a matter of international conservation concern.

高自然价值地区的人为开发压力越来越大，对全球野生动物保护提出了巨大挑战。葡萄牙南部的塔霍河口是东大西洋迁徙路线 (EAF) 中迁徙鸻鹬最重要的湿地之一。然而，2020 年，葡萄牙政府批准在塔霍河口中心建设新的里斯本国际机场。在进近和起飞期间在低空飞行的密集飞机交通预计将穿过河口，在很大程度上与重要的潮间带觅食区重叠。在这里，我们的目标是量化因飞机飞越造成的干扰（噪音）而导致的塔霍河口潮间带地区鸻鹬保护价值的潜在损失。使用整个潮间带河口地区越冬鸻鸟丰度和分布的综合数据集，我们首先使用空间优先级方法确定了优先保护区域。然后，我们通过排除由于强烈的空中交通噪音而可能变得不适合或严重未被鸟类利用的区域，进行了重置成本分析。我们的研究结果表明，仅就越冬鸟类的潮间带觅食区而言，新里斯本机场的实施可能会导致塔霍河口的保护价值损失高达 30%。如果还考虑对潮上栖息地和过境鸟类的影响，全球影响可能会更大。塔霍河口对我们分析的 10 个物种中的 6 个具有国际重要性，只是电弧炉沿线已经枯竭的站点网络之一。因此，对塔霍河口鸟类种群的负面影响将产生影响并破坏其他地方的保护工作。因此，塔霍河口鸻鹬的困境是一个国际保护问题。