Climate change has different and sometimes divergent effects on terrestrial and marine food webs, and in coastal ecosystems, these effects are tightly interlinked. Responses of opportunistic coastal predators and scavengers to climate change may thus be complex and potentially highly flexible, and can simultaneously serve as indicators of, and have profound impacts on, lower trophic levels. Gaining mechanistic understanding of these responses is therefore important, but often not feasible due to lack of long-term data from marked individuals. Here, we used a Bayesian integrated population model (IPM) to elucidate the effects of arctic warming and concurrent changes in terrestrial and marine resource availability on population dynamics of the opportunistic arctic fox (Vulpes lagopus) in Svalbard. Joint analysis of four types of data (den survey, age-at-harvest, placental scars, mark-recovery) revealed relatively stable population size and age structure over the last 22 yr (1997–2019) despite rapid environmental change linked to climate warming. This was related to the fact that terrestrial resources (reindeer carcasses, geese) became more abundant while the availability of marine resources (seal pups/carrion) decreased, and was driven by divergent trends in different vital rates (e.g., increased pregnancy rate but decreased pup survival). Balanced contributions of survival vs. reproduction and of immigration vs. local demography further stabilized population size. Our study thus sheds light on the mechanisms underlying population dynamics of opportunistic carnivores exploiting terrestrial and marine resources and suggests that exploitation of resources across different ecosystems can buffer predators against climate change. Additionally, it highlights the large potential of IPMs as tools to understand and predict the effects of environmental change on wildlife populations, even when data on marked individuals are sparse.

中文翻译：

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陆地和海洋资源的贡献在快速变化的气候中稳定了捕食者种群

气候变化对陆地和海洋食物网有不同的、有时是不同的影响，而在沿海生态系统中，这些影响是紧密相连的。因此，机会主义的沿海捕食者和食腐动物对气候变化的反应可能很复杂，而且可能高度灵活，并且可以同时作为较低营养水平的指标，并对较低的营养水平产生深远的影响。因此，获得对这些反应的机械理解很重要，但由于缺乏来自标记个体的长期数据，通常不可行。在这里，我们使用贝叶斯综合种群模型 (IPM) 来阐明北极变暖和陆地和海洋资源可用性的并发变化对机会主义北极狐 ( Vulpes lagopus)种群动态的影响) 在斯瓦尔巴群岛。对四类数据（巢穴调查、收获年龄、胎盘疤痕、标记恢复）的联合分析显示，尽管与气候变暖相关的环境迅速变化，但过去 22 年（1997-2019 年）的人口规模和年龄结构相对稳定. 这与陆地资源（驯鹿尸体、鹅）变得更加丰富而海洋资源（海豹幼崽/腐肉）的可用性减少有关，并且是由不同生命率的不同趋势驱动的（例如，怀孕率增加但减少幼崽生存）。生存与繁殖以及移民与当地人口的平衡贡献进一步稳定了人口规模。因此，我们的研究揭示了利用陆地和海洋资源的机会主义食肉动物种群动态的潜在机制，并表明在不同生态系统中开发资源可以缓冲捕食者对气候变化的影响。此外，它还强调了 IPM 作为工具来理解和预测环境变化对野生动物种群的影响的巨大潜力，即使有关标记个体的数据很少。