Sutton Alex O, Strickland Dan, Freeman Nikole E, Norris D Ryan
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.
1063 Oxtongue Lake Road, Dwight, ON, Canada.
Glob Chang Biol. 2020 Dec 21. doi: 10.1111/gcb.15445.
Understanding how events throughout the annual cycle are linked is important for predicting variation in individual fitness, but whether and how carry-over effects scale up to influence population dynamics is poorly understood. Using 38 years of demographic data from Algonquin Provincial Park, Ontario, and a full annual cycle integrated population model, we examined the influence of environmental conditions and density on the population growth rate of Canada jays (Perisoreus canadensis), a resident boreal passerine that relies on perishable cached food for over-winter survival and late-winter breeding. Our results demonstrate that fall environmental variables, most notably the number of freeze-thaw events, carried over to influence late-winter fecundity, which, in turn, was the main vital rate driving population growth. These results are consistent with the hypothesis that warmer and more variable fall conditions accelerate the degradation of perishable stored food that is relied upon for successful reproduction. Future warming during the fall and winter may compromise the viability of cached food that requires consistent subzero temperatures for effective preservation, potentially exacerbating climate-driven carry-over effects that impact long-term population dynamics.
了解全年周期中各个事件之间的联系对于预测个体适应性的变化很重要，但对于残留效应是否以及如何扩大影响种群动态，我们却知之甚少。利用安大略省阿尔冈昆省立公园38年的人口统计数据以及一个完整年度周期的综合种群模型，我们研究了环境条件和密度对灰噪鸦（Perisoreus canadensis）种群增长率的影响。灰噪鸦是一种栖息在北方的留鸟雀形目鸟类，依靠易腐的贮藏食物度过冬季并在冬末繁殖。我们的研究结果表明，秋季环境变量，尤其是冻融事件的数量，会持续影响冬末的繁殖力，而繁殖力又是推动种群增长的主要生命率。这些结果与以下假设一致：秋季气候变暖且变化更大，会加速依赖贮藏食物成功繁殖的易腐食物的降解。秋季和冬季未来的变暖可能会危及需要持续低温才能有效保存的贮藏食物的生存能力，从而可能加剧影响长期种群动态的气候驱动残留效应。
