Assessing the effects of climate and interspecific relationships on communities is challenging because of the complex interplay between species population dynamics, their interactions, and the need to integrate information across several biological levels (individuals, populations, communities). Usually used to quantify single-species demography, integrated population models (IPMs) have recently been extended to communities. These models allow fitting multispecies matrix models to data from multiple sources while simultaneously accounting for uncertainty in each data source. We used multispecies IPMs accommodating climatic variables to quantify the relative contribution of climate vs. interspecific interactions on demographic parameters, such as survival and breeding success, in the dynamics of a predator–prey system. We considered a stage-structured predator–prey system combining 22 yr of capture–recapture data and population counts of two seabirds, the Brown Skua (Catharacta lönnbergi) and its main prey the Blue Petrel (Halobaena caerulea), both breeding on the Kerguelen Islands in the Southern Ocean. Our results showed that climate and predator–prey interactions drive the demography of skuas and petrels in different ways. The breeding success of skuas appeared to be largely driven by the number of petrels and to a lesser extent by intraspecific density dependence. In contrast, there was no evidence of predation effects on the demographic parameters of petrels, which were affected by oceanographic factors. We conclude that bottom-up mechanisms are the main drivers of this skua–petrel system.

中文翻译：

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多物种综合种群模型揭示了海鸟捕食者-猎物系统自下而上的动态

评估气候和种间关系对群落的影响具有挑战性，因为物种种群动态、它们的相互作用以及整合多个生物层面（个人、种群、群落）信息的需要之间存在复杂的相互作用。通常用于量化单一物种人口统计的综合种群模型 (IPM) 最近已扩展到社区。这些模型允许将多物种矩阵模型拟合到来自多个来源的数据，同时考虑每个数据来源的不确定性。我们使用适应气候变量的多物种 IPM 来量化气候与种间相互作用对捕食者 - 猎物系统动态中的人口参数（例如生存和繁殖成功）的相对贡献。Catharacta lönnbergi）及其主要猎物蓝海燕（Halobaena caerulea），都在南大洋的凯尔盖朗群岛繁殖。我们的结果表明，气候和捕食者-猎物的相互作用以不同的方式推动了贼鸥和海燕的人口结构。贼鸥的繁殖成功似乎主要受海燕数量的驱动，在较小程度上受种内密度依赖性驱动。相比之下，没有证据表明捕食对海燕的人口统计参数有影响，海燕受海洋因素的影响。我们得出结论，自下而上的机制是这种贼鸥-海燕系统的主要驱动力。