Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT 06520-8106, USA.
J Anim Ecol. 2012 Jul;81(4):914-25. doi: 10.1111/j.1365-2656.2012.01958.x. Epub 2012 Feb 28.
1. Global climate has changed significantly during the past 30 years and especially in northern temperate regions which have experienced poleward shifts in temperature regimes. While there is evidence that some species have responded by moving their distributions to higher latitudes, the efficiency of this response in tracking species' climatic niche boundaries over time has yet to be addressed. 2. Here, we provide a continental assessment of the temporal structure of species responses to recent spatial shifts in climatic conditions. We examined geographic associations with minimum winter temperature for 59 species of winter avifauna at 476 Christmas Bird Count circles in North America from 1975 to 2009 under three sampling schemes that account for spatial and temporal sampling effects. 3. Minimum winter temperature associated with species occurrences showed an overall increase with a weakening trend after 1998. Species displayed highly variable responses that, on average and across sampling schemes, contained a strong lag effect that weakened in strength over time. In general, the conservation of minimum winter temperature was relevant when all species were considered together but only after an initial lag period (c. 35 years) was overcome. The delayed niche tracking observed at the combined species level was likely supported by the post1998 lull in the warming trend. 4. There are limited geographic and ecological explanations for the observed variability, suggesting that the efficiency of species' responses under climate change is likely to be highly idiosyncratic and difficult to predict. This outcome is likely to be even more pronounced and time lags more persistent for less vagile taxa, particularly during the periods of consistent or accelerating warming. Current modelling efforts and conservation strategies need to better appreciate the variation, strength and duration of lag effects and their association with climatic variability. Conservation strategies in particular will benefit through identifying and maintaining dispersal corridors that accommodate diverging dispersal strategies and timetables.
过去 30 年来，全球气候发生了显著变化，尤其是在经历了温度制度向极地方向转移的北温带地区。虽然有证据表明，一些物种已经通过将其分布转移到更高的纬度来做出反应，但这种反应在跟踪物种气候生态位边界随时间的变化方面的效率尚未得到解决。
在这里，我们提供了对物种对最近气候条件空间变化的时间结构的大陆评估。我们检查了 1975 年至 2009 年北美 476 个圣诞节鸟类计数圈中 59 种冬季鸟类物种的最低冬季温度与地理位置的关系，这些物种考虑了三种采样方案，这些方案考虑了空间和时间采样效应。
与物种出现相关的最低冬季温度总体呈上升趋势，1998 年后呈减弱趋势。物种表现出高度可变的反应，平均而言，在所有采样方案中，都存在强烈的滞后效应，随着时间的推移，滞后效应逐渐减弱。一般来说，当考虑所有物种时，最低冬季温度的保护是相关的，但只有在克服了初始滞后期（约 35 年）之后。在综合物种水平上观察到的延迟生态位跟踪可能是由于 1998 年后变暖趋势的放缓而得到支持。
观察到的可变性没有有限的地理和生态解释，这表明在气候变化下，物种反应的效率可能是高度特殊的，难以预测。这种结果在不太灵活的分类群中可能更为明显，滞后时间更长，特别是在持续或加速变暖的时期。当前的建模工作和保护策略需要更好地理解滞后效应的变化、强度和持续时间及其与气候变异性的关联。保护策略尤其将受益于确定和维护适应不同扩散策略和时间表的扩散走廊。
