British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK.
Department of Geography, University of Florida, Gainesville, FL 32611, USA.
Biol Lett. 2022 Aug;18(8):20220186. doi: 10.1098/rsbl.2022.0186. Epub 2022 Aug 31.
Climate change affects the phenology of annual life cycle events of organisms, such as reproduction and migration. Shifts in the timing of these events could have important population implications directly, or provide information about the mechanisms driving population trajectories, especially if they differ between life cycle event. We examine if such shifts occur in a declining migratory passerine bird (willow warbler, ), which exhibits latitudinally diverging population trajectories. We find evidence of phenological shifts in breeding initiation, breeding progression and moult that differ across geographic and spring temperature gradients. Moult initiation following warmer springs advances faster in the south than in the north, resulting in proportionally shorter breeding seasons, reflecting higher nest failure rates in the south and in warmer years. Tracking shifts in multiple life cycle events allowed us to identify points of failure in the breeding cycle in regions where the species has negative population trends, thereby demonstrating the utility of phenology analyses for illuminating mechanistic pathways underlying observed population trajectories.
气候变化会影响生物的年生活周期事件的物候，例如繁殖和迁徙。这些事件时间的变化可能会直接对种群产生重要影响，或者提供有关驱动种群轨迹的机制的信息，特别是如果它们在生命周期事件之间存在差异。我们研究了在一种迁徙性鸣禽（柳莺）中是否存在这样的变化，这种鸟的种群轨迹存在纬度上的差异。我们发现繁殖开始、繁殖进展和换羽的物候变化的证据，这些变化在地理和春季温度梯度上有所不同。在温暖的春天之后，换羽开始得更快，南部比北部快，导致繁殖季节相对较短，反映出南部和温暖年份的筑巢失败率更高。跟踪多个生命周期事件的变化使我们能够在该物种出现负种群趋势的地区确定繁殖周期中的失败点，从而证明物候分析对于阐明观察到的种群轨迹背后的机制途径具有实用性。
