Data from: Tracking ice phenology by migratory waterbirds: settling phenology and breeding success of species with divergent population trends

Dependence on climate-driven environmental cues in the initiation of life cycle stages is a critical attribute when assessing vulnerability of species to climate change impacts. This study focused on spring ice phenology as a cue to the settling of migratory waterbirds, asking whether there is an asynchrony between ice phenology and setting phenology that could affect breeding success of six species with divergent population trends. In the 37 study lakes in southeastern Finland, the ice-out date not only varied considerably between years, but became progressively earlier during the study period, 1991–2018. Settling phenology of all species tracked inter-annual variation in ice phenology. However, the degree of asynchrony between ice phenology and settling phenology varied between species, allowing discrimination between early and late settlers. Considerable inter-annual variation also occurred within species, but in only one species did the degree of asynchrony correlate with the ice-out date: for the horned grebe Podiceps auritus an earlier ice-out date meant greater asynchrony between settling phenology and ice phenology. The degree of asynchrony between settling phenology and ice phenology did not affect breeding success in any species. However, ice phenology per se affected breeding success of horned grebes: earlier ice-out was associated with lower annual breeding success. Breeding numbers of horned grebe showed a long-term decline. Results suggest that short-distance migratory birds are able to respond to climate change-driven phenological changes in their breeding environments, and that this ability may not depend on the relative timing of breeding.物种生活周期阶段的启动依赖气候驱动的环境信号，这是评估物种对气候变化影响脆弱性的关键特征。本研究以春季冰物候（ice phenology）作为迁徙水鸟迁抵定居的信号，探讨冰物候与迁抵物候（settling phenology）之间是否存在物候不同步现象，该现象可能会影响六种种群趋势各异的物种的繁殖成功率。在芬兰东南部的37个研究湖泊中，冰融日期不仅年际差异显著，且在1991–2018年的研究时段内呈持续提前趋势。所有研究物种的迁抵物候均追踪冰物候的年际变化。然而，不同物种间冰物候与迁抵物候的不同步程度存在差异，据此可区分早抵达与晚抵达物种。同一物种内部也存在显著的年际变化，但仅角䴙䴘（horned grebe，Podiceps auritus）这一个物种的不同步程度与冰融日期相关：冰融日期越早，其迁抵物候与冰物候的不同步程度越高。迁抵物候与冰物候的不同步程度并未对任一物种的繁殖成功率产生影响。但冰物候本身会影响角䴙䴘的繁殖成功率：冰融日期越早，其年度繁殖成功率越低。角䴙䴘的繁殖种群数量呈长期下降趋势。研究结果表明，短距离迁徙鸟类能够响应繁殖环境中气候变化驱动的物候变化，且这种能力可能并不依赖于繁殖的相对时序。