Canadian Wildlife Service, Environment and Climate Change Canada, Ottawa, ON, Canada.
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Glob Chang Biol. 2020 Jul;26(7):3788-3798. doi: 10.1111/gcb.15085. Epub 2020 Apr 29.
Understanding the scales at which environmental variability affects populations is critical for projecting population dynamics and species distributions in rapidly changing environments. Here we used a multilevel Bayesian analysis of range-wide survey data for Adélie penguins to characterize multidecadal and annual effects of sea ice on population growth. We found that mean sea ice concentration at breeding colonies (i.e., "prevailing" environmental conditions) had robust nonlinear effects on multidecadal population trends and explained over 85% of the variance in mean population growth rates among sites. In contrast, despite considerable year-to-year fluctuations in abundance at most breeding colonies, annual sea ice fluctuations often explained less than 10% of the temporal variance in population growth rates. Our study provides an understanding of the spatially and temporally dynamic environmental factors that define the range limits of Adélie penguins, further establishing this iconic marine predator as a true sea ice obligate and providing a firm basis for projection under scenarios of future climate change. Yet, given the weak effects of annual sea ice relative to the large unexplained variance in year-to-year growth rates, the ability to generate useful short-term forecasts of Adélie penguin breeding abundance will be extremely limited. Our approach provides a powerful framework for linking short- and longer term population processes to environmental conditions that can be applied to any species, facilitating a richer understanding of ecological predictability and sensitivity to global change.
了解环境变异性在何种尺度上影响种群对于预测快速变化环境中的种群动态和物种分布至关重要。在这里，我们使用阿德雷企鹅的全范围调查数据的多层次贝叶斯分析来描述海冰对种群增长的多年和年度影响。我们发现，繁殖地的平均海冰浓度（即“普遍”的环境条件）对多年代种群趋势有强大的非线性影响，解释了各地点之间平均种群增长率差异的 85%以上。相比之下，尽管大多数繁殖地的丰度存在相当大的年际波动，但年度海冰波动通常解释了种群增长率的时间方差的不到 10%。我们的研究提供了对定义阿德利企鹅范围限制的空间和时间动态环境因素的理解，进一步将这种标志性的海洋捕食者确立为真正的海冰专性动物，并为未来气候变化情景下的预测提供了坚实的基础。然而，鉴于年度海冰的影响相对较小，而年际增长率的方差很大，无法对阿德利企鹅繁殖数量进行有用的短期预测。我们的方法提供了一个强大的框架，将短期和长期种群过程与环境条件联系起来，可应用于任何物种，从而更深入地了解生态可预测性和对全球变化的敏感性。
