利用机器学习和地理标记的公民科学数据解开鸟类死亡事件的物种级别影响因素

由于全球气候变化，极端天气和自然灾害在过去几十年中显著增加。这些突发的环境变化通常会通过直接影响种群结构或间接导致栖息地丧失或碎片化，对地球上的生物物种造成重大影响。2020年8月至10月，西部和中部美国报告了大量鸟类的死亡事件，依据现有证据，这可能是由冬季风暴和野火引起的。然而，不同物种对环境变化的反应差异仍然不太清楚。在本研究中，我们集中研究了由公民科学家记录的死亡观测数量最高的三种鸟类（即威尔逊莺、仓鸮和普通海鸥），并使用随机森林模型分析它们对这两种环境变化的反应。我们发现威尔逊莺的死亡主要受到早期冬季风暴的影响，在日均最大降雪量较高的地区观察到更多的死亡。仓鸮对野火影响和冬季风暴均有反应，但在野火引发空气污染较重的地区观察到更多的死亡。而这两种事件对普通海鸥的影响较为温和，普通海鸥的死亡可能与较高的水温有关。我们的研究结果强调了不同物种对环境变化的特异性反应，这为生态系统对环境变化的适应能力和鸟类保护提供了重要的见解。

Due to global climate change, extreme weather events and natural disasters have increased significantly over the past few decades. These abrupt environmental changes typically exert substantial impacts on Earth's biological species, either by directly altering population structures or indirectly triggering habitat loss and fragmentation. Between August and October 2020, a large number of bird mortality incidents were reported in the western and central United States. Based on existing evidence, these mortalities may have been caused by winter storms and wildfires. However, the differential responses of species to environmental changes remain largely unclear. In this study, we focus on three bird species with the highest mortality records documented by citizen scientists: Wilson's Warbler, Barn Owl and Common Gull, and use random forest models to analyze their responses to these two environmental changes. We find that the mortality of Wilson's Warbler is primarily driven by early winter storms, with more mortalities observed in regions with higher mean daily maximum snowfall. Barn Owls respond to both wildfires and winter storms, with elevated mortalities detected in areas where wildfires induced severe air pollution. The impacts of these two events on Common Gulls are relatively mild, and their mortalities may be correlated with higher water temperatures. Our results highlight the species-specific responses of birds to environmental changes, which offers critical insights into the adaptive capacity of ecosystems to environmental shifts and bird conservation practices.