Département de Biologie and Centre d'Études Nordiques, Université Laval, 1045 Av. de la Médecine, Quebec, QC, G1V 0A6, Canada.
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Oecologia. 2021 Nov;197(3):633-650. doi: 10.1007/s00442-021-05055-x. Epub 2021 Oct 7.
For species inhabiting areas at the limit of their environmental tolerance, extreme events often drive population persistence. However, because extreme events are uncommon, their effects on population dynamics of expanding species are poorly known. We examined how extreme climate events in winter and summer affected three populations of wild turkeys occupying a natural climate gradient at the northern edge of their range. First, we examined the mechanism by which vital rates affect the population growth rate. Second, we developed a climate-dependent structured population model. Finally, by linking this population model to IPCC-class climate projections, we projected wild turkey population abundance in response to the frequency of extreme snow events by 2100 for the northernmost population. We showed that the population dynamics of the three populations is driven through different pathways expected from the theory of invading population dynamics; that those populations were mainly limited by heavy snow that decreases winter survival by restraining food access; and that a population of immigrant is projected to decline at the northern species range. This study exemplifies how extreme events affect population dynamics and range expansion of temperate species at the northern edge of the distribution.
对于生活在环境耐受极限区域的物种来说，极端事件通常会驱动种群的持续存在。然而，由于极端事件并不常见，它们对正在扩张的物种的种群动态的影响知之甚少。我们研究了冬季和夏季的极端气候事件如何影响三个野生火鸡种群，这些种群栖息在其分布范围北缘的自然气候梯度上。首先，我们研究了关键比率如何影响种群增长率的机制。其次，我们开发了一个依赖气候的结构化种群模型。最后，通过将这个种群模型与 IPCC 类气候预测相联系，我们预测了到 2100 年，最北部种群的野生火鸡数量对极端雪事件频率的响应。我们表明，三个种群的种群动态是通过入侵种群动态理论所预期的不同途径驱动的；这些种群主要受到大雪的限制，大雪通过限制食物获取来降低冬季存活率；预计一个移民种群将在物种分布的北部边缘减少。这项研究说明了极端事件如何影响温带物种在分布北缘的种群动态和扩展。
