CESAM, Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa 1749-016, Portugal.
Falklands Conservation, Stanley, FIQQ 1ZZ Falkland Islands, UK.
Biol Lett. 2023 Feb;19(2):20220408. doi: 10.1098/rsbl.2022.0408. Epub 2023 Feb 1.
Extreme weather events are among the most critical aspects of climate change, but our understanding of their impacts on biological populations remains limited. Here, we exploit the rare opportunity provided by the availability of concurrent longitudinal demographic data on two neighbouring marine top predator populations (the black-browed albatross, , breeding in two nearby colonies) hit by an exceptionally violent storm during one study year. The aim of this study is to quantify the demographic impacts of extreme events on albatrosses and test the hypothesis that extreme events would synchronously decrease survival rates of neighbouring populations. Using demographic modelling we found that, contrary to our expectation, the storm affected the survival of albatrosses from only one of the two colonies, more than doubling the annual mortality rate compared to the study average. Furthermore, the effects of storms on adult survival would lead to substantial population declines (up to 2% per year) under simulated scenarios of increased storm frequencies. We, therefore, conclude that extreme events can result in very different local-scale impacts on sympatric populations. Crucially, by driving demographic asynchrony, extreme events can hamper our understanding of the demographic responses of wild populations to mean, long-term shifts in climate.
极端天气事件是气候变化最关键的方面之一，但我们对它们对生物种群的影响的理解仍然有限。在这里，我们利用了一个难得的机会，即利用了在一个研究年度中，两个相邻的海洋顶级捕食者种群（在两个附近的繁殖地繁殖的黑眉信天翁，）同时提供的纵向人口统计数据。本研究的目的是量化极端事件对信天翁的人口影响，并检验极端事件会同步降低相邻种群的存活率的假设。使用人口统计模型，我们发现，与我们的预期相反，风暴仅影响了两个繁殖地之一的信天翁的存活率，与研究平均值相比，每年的死亡率增加了一倍以上。此外，根据模拟的风暴频率增加情景，风暴对成年个体存活率的影响将导致种群数量大幅下降（每年高达 2%）。因此，我们得出结论，极端事件可能会对同域种群产生非常不同的局部影响。至关重要的是，极端事件通过驱动人口统计上的不同步，可能会阻碍我们对野生种群对长期平均气候变化的人口响应的理解。
