Boelman Natalie T, Krause Jesse S, Sweet Shannan K, Chmura Helen E, Perez Jonathan H, Gough Laura, Wingfield John C
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA.
Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, 10964, USA.
Oecologia. 2017 Sep;185(1):69-80. doi: 10.1007/s00442-017-3907-3. Epub 2017 Aug 4.
Arctic regions are warming rapidly, with extreme weather events increasing in frequency, duration, and intensity just as in other regions. Many studies have focused on how shifting seasonality in environmental conditions affects vegetation phenology, while far fewer have examined how the breeding phenology of arctic fauna responds. We studied two species of long-distance migratory songbirds, Lapland longspurs, Calcarius lapponicus, and white-crowned sparrows, Zonotrichia leucophrys gambelii, across five consecutive breeding seasons in northern Alaskan tundra. We aimed to understand how spring environmental conditions affected breeding cycle phenology, including the timing of arrival on breeding grounds, territory establishment, and clutch initiation. Spring temperatures, precipitation, and snow-free dates differed significantly among years, with 2013 characterized by unusually late snow cover. In response, we found a significant delay in breeding-cycle phenology for both study species in 2013 relative to other study years: the first bird observed was delayed by 6-10 days, with mean arrival by 3-6 days, territory establishment by 6-13 days, and clutch initiation by 4-10 days. Further, snow cover, temperature, and precipitation during the territory establishment period were important predictors of clutch initiation dates for both species. These findings suggest that Arctic-breeding passerine communities may have the flexibility required to adjust breeding phenology in response to the increasingly extreme and unpredictable environmental conditions-although future generations may encounter conditions that exceed their current range of phenological flexibility.
北极地区正在迅速变暖，极端天气事件的频率、持续时间和强度都在增加，就像其他地区一样。许多研究关注环境条件季节性变化如何影响植被物候，而研究北极动物繁殖物候如何响应的则少得多。我们在阿拉斯加北部苔原连续五个繁殖季节研究了两种长距离迁徙鸣禽，拉普兰铁爪鹀（Calcarius lapponicus）和白冠雀（Zonotrichia leucophrys gambelii）。我们旨在了解春季环境条件如何影响繁殖周期物候，包括到达繁殖地的时间、领地建立和产卵开始时间。不同年份的春季温度、降水量和无雪日期差异显著，2013年的特点是积雪异常晚。相应地，我们发现相对于其他研究年份，2013年这两种研究物种的繁殖周期物候都有显著延迟：观察到的第一只鸟延迟了6 - 10天，平均到达时间延迟了3 - 6天，领地建立延迟了6 - 13天，产卵开始延迟了4 - 10天。此外，领地建立期间的积雪、温度和降水量是这两个物种产卵开始日期的重要预测因素。这些发现表明，在北极繁殖的雀形目鸟类群落可能具有根据日益极端和不可预测的环境条件调整繁殖物候所需的灵活性——尽管后代可能会遇到超出其当前物候灵活性范围的条件。
