Understanding how populations respond to variability in environmental conditions and interspecific interactions is one of the biggest challenges of population ecology, particularly in the context of global change. Although many studies have investigated population responses to climate change, very few have explicitly integrated interspecific relationships when studying these responses. In this study, we aimed to understand the combined effects of interspecific interactions and environmental conditions on the demographic parameters of a prey–predator system of three sympatric seabird populations breeding in Antarctica: the south polar skua (Catharacta maccormicki) and its two main preys during the breeding season, the Adélie penguin (Pygoscelis adeliae) and the emperor penguin (Aptenodytes forsteri). We built a two‐species integrated population model (IPM) with 31 years of capture–recapture and count data and provided a framework that made it possible to estimate the demographic parameters and abundance of a predator–prey system in a context where capture–recapture data were not available for one species. Our results showed that predator–prey interactions and local environmental conditions differentially affected south polar skuas depending on their breeding state of the previous year. Concerning prey–predator relationships, the number of Adélie penguin breeding pairs showed a positive effect on south polar skua survival and breeding probability, and the number of emperor penguin dead chicks showed a positive effect on the breeding success of south polar skuas. In contrast, there was no evidence for an effect of the number of south polar skuas on the demography of Adélie penguins. We also found an important impact of sea ice conditions on both the dynamics of south polar skuas and Adélie penguins. Our results suggest that this prey–predator system is mostly driven by bottom‐up processes and local environmental conditions.

中文翻译：

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自下而上的效应驱动南极海鸟捕食者-被捕食系统的动态


了解种群如何应对环境条件的变化和种间相互作用是种群生态学面临的最大挑战之一，特别是在全球变化的背景下。尽管许多研究调查了人口对气候变化的反应，但很少有研究在研究这些反应时明确整合种间关系。在这项研究中，我们旨在了解种间相互作用和环境条件对在南极洲繁殖的三种同域海鸟种群的猎物-捕食者系统的人口统计参数的综合影响：南极贼鸥（长春花）及其在繁殖季节的两个主要猎物阿德利企鹅（阿德利亚小蠹）和帝企鹅（福斯特氏足螨）。我们利用 31 年的捕获-再捕获和计数数据建立了一个双物种综合种群模型 (IPM)，并提供了一个框架，使得在捕获-再捕获的背景下​​估计捕食者-被捕食者系统的人口统计参数和丰度成为可能。没有某一物种的数据。我们的结果表明，捕食者与猎物的相互作用和当地环境条件对南极贼鸥的影响不同，具体取决于它们上一年的繁殖状态。在猎物-捕食者关系方面，阿德利企鹅繁殖对的数量对南极贼鸥的生存和繁殖概率显示出积极的影响，而帝企鹅死亡幼崽的数量对南极贼鸥的繁殖成功率显示出积极的影响。相比之下，没有证据表明南极贼鸥的数量对阿德利企鹅的人口统计有影响。 我们还发现海冰状况对南极贼鸥和阿德利企鹅的动态产生重要影响。我们的结果表明，这种猎物-捕食者系统主要是由自下而上的过程和当地环境条件驱动的。