Long-term studies to understand biodiversity changes remain scarce- especially so in tropical mountains. Here, we document changes between 1911 and 2016 to the bird community in the cloud forest of San Antonio, a mountain ridge in the Colombian Andes. We evaluated the effects of past land-use change and assessed species vulnerability to climate disruption. Forest cover decreased from 95% to 50% by 1959 and 33 forest species were extirpated. From then to 1990, forest cover remained stable, and an additional 15 species were lost-a total of 29% of the forest community. Thereafter, forest cover increased by 26% and 17 species recolonized. The main cause of extirpations was the loss of connections to adjacent forests. Currently, of the 31 (19%) extirpated birds, 25 have ranges peripheral to San Antonio, mostly in the lowlands. Most remain regionally, but broken forest connections limit their recolonization. Other causes of extirpation are hunting, wildlife trade, and water diversion. Bird community changes include: (1) A shift from predominantly common species to a prevalence of rare ones; (2) Forest generalists replaced forest specialists that require old-growth, and (3) Functional groups such as large-body frugivores and nectarivores declined disproportionally. Moreover, we found that of the remaining 122 forest birds, 19 species are vulnerable to climate disruption, and 10 have declined in abundance. Our results inform four major topics that transcend this case study. First, we show unequivocal species losses and changes in community structure and abundance at the local scale. Second, we find that increasing habitat stops delayed extirpations and help species repopulate. Third, peripheral species to a region are more prone to extirpation when forests become fragmented. Fourth, land-use changes increase species vulnerability to climate change and threaten their persistence. We suggest measures that reverse landscape transformation can restore biodiversity and improve resistance to future threats. Article impact statement: 100 years of land-use change have produced bird extirpations and abundance declines in an Andean mountain site. This article is protected by copyright. All rights reserved.

中文翻译：

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100 年来土地利用变化的安第斯云雾林中的鸟类灭绝和群落动态

了解生物多样性变化的长期研究仍然很少——尤其是在热带山区。在这里，我们记录了 1911 年至 2016 年间，哥伦比亚安第斯山脉的山脊圣安东尼奥云雾林中鸟类群落的变化。我们评估了过去土地利用变化的影响，并评估了物种对气候破坏的脆弱性。到 1959 年，森林覆盖率从 95% 下降到 50%，33 种森林物种被灭绝。从那时到 1990 年，森林覆盖率保持稳定，另外 15 个物种消失了——占森林群落总数的 29%。此后，森林覆盖率增加了 26%，有 17 个物种重新定居。灭绝的主要原因是失去与邻近森林的联系。目前，在 31 只 (19%) 灭绝的鸟类中，有 25 只在圣安东尼奥附近有分布，主要在低地。大多数留在区域，但断裂的森林联系限制了他们的重新殖民。灭绝的其他原因是狩猎、野生动物贸易和水改道。鸟类群落的变化包括： (1) 从以常见物种为主的转变为稀有物种的流行；(2) 森林多面手取代了需要老式生长的森林专家，以及 (3) 大型食果动物和食蜜动物等功能群体不成比例地下降。此外，我们发现在剩余的 122 种森林鸟类中，有 19 种易受气候破坏影响，10 种数量减少。我们的结果为超越本案例研究的四个主要主题提供了信息。首先，我们在当地范围内展示了明确的物种损失以及群落结构和丰度的变化。其次，我们发现增加栖息地可以阻止延迟灭绝并帮助物种重新繁殖。第三，当森林变得支离破碎时，一个地区的外围物种更容易灭绝。第四，土地利用的变化增加了物种对气候变化的脆弱性并威胁到它们的持久性。我们建议采取措施，逆转景观转变可以恢复生物多样性并提高对未来威胁的抵抗力。文章影响声明：100 年的土地利用变化导致安第斯山区鸟类灭绝和数量下降。本文受版权保护。版权所有。100 年的土地利用变化导致安第斯山区鸟类灭绝和数量下降。本文受版权保护。版权所有。100 年的土地利用变化导致安第斯山区鸟类灭绝和数量下降。本文受版权保护。版权所有。