Density-dependent feedback is recognized as important regulatory mechanisms of population size. Considering the spatial scales over which such feedback operates has advanced our theoretical understanding of metapopulation dynamics. Yet, metapopulation models are rarely fit to time-series data and tend to omit details of the natural history and behavior of long-lived, highly mobile species such as colonial mammals and birds. Seabird metapopulations consist of breeding colonies that are connected across large spatial scales, within a heterogeneous marine environment that is increasingly affected by anthropogenic disturbance. Currently, we know little about the strength and spatial scale of density-dependent regulation and connectivity between colonies. Thus, many important seabird conservation and management decisions rely on outdated assumptions of closed populations that lack density-dependent regulation. We investigated metapopulation dynamics and connectivity in an exemplar seabird species, the Northern gannet (Morus bassanus), using more than a century of census data of breeding colonies distributed across the Northeast Atlantic. We developed and fitted these data to a novel hierarchical Bayesian state-space model, to compare increasingly complex scenarios of metapopulation regulation through lagged, local, regional, and global density dependence, as well as different mechanisms for immigration. Models with conspecific attraction fit the data better than the equipartitioning of immigrants. Considering local and regional density dependence jointly improved model fit slightly, but importantly, future colony size projections based on different mechanistic regulatory scenarios varied widely: a model with local and regional dynamics estimated a lower metapopulation capacity (645,655 Apparently Occupied Site [AOS]) and consequently higher present saturation (63%) than a model with local density dependence (1,367,352 AOS, 34%). Our findings suggest that metapopulation regulation in the gannet is more complex than traditionally assumed, and highlight the importance of using models that consider colony connectivity and regional dynamics for conservation management applications guided by precautionary principles. Our study advances our understanding of metapopulation dynamics in long-lived colonial species and our approach provides a template for the development of metapopulation models for colonially living birds and mammals.

中文翻译：

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群体种群调节作用于多个空间尺度：来自一个世纪的海鸟群落普查数据的见解

密度依赖反馈被认为是人口规模的重要调节机制。考虑到这种反馈运作的空间尺度，提高了我们对集合种群动力学的理论理解。然而，集合种群模型很少适合时间序列数据，并且往往会忽略长寿、高度流动的物种（如殖民地哺乳动物和鸟类）的自然历史和行为的细节。海鸟集合种群由跨大空间尺度相连的繁殖群组成，处于日益受到人为干扰影响的异质海洋环境中。目前，我们对密度依赖性调节和菌落间连通性的强度和空间尺度知之甚少。因此，许多重要的海鸟保护和管理决策依赖于封闭种群的过时假设，这些种群缺乏密度依赖性监管。我们研究了一个典型海鸟物种北方塘鹅的集合种群动态和连通性（桑树)，使用了一个多世纪以来分布在东北大西洋的繁殖地的人口普查数据。我们开发了这些数据并将其拟合到一个新的分层贝叶斯状态空间模型中，以通过滞后的、局部的、区域的和全球的密度依赖性以及不同的移民机制来比较日益复杂的集合种群调节场景。具有同种吸引力的模型比移民的均分更适合数据。考虑到局部和区域密度依赖性共同改进了模型的拟合度，但重要的是，基于不同机制监管情景的未来蜂群大小预测差异很大：具有局部和区域动态的模型估计较低的集合种群容量（645，655 Apparently Occupied Site [AOS])，因此当前饱和度 (63%) 高于具有局部密度依赖性的模型（1,367,352 AOS，34%）。我们的研究结果表明，塘鹅中的集合种群调节比传统上假设的更为复杂，并强调了使用考虑群体连通性和区域动态的模型在预防原则指导下的保护管理应用中的重要性。我们的研究促进了我们对长寿殖民物种集合种群动态的理解，我们的方法为殖民生活的鸟类和哺乳动物集合种群模型的开发提供了模板。并强调使用考虑群体连通性和区域动态的模型在预防原则指导下的保护管理应用中的重要性。我们的研究促进了我们对长寿殖民物种集合种群动态的理解，我们的方法为殖民生活的鸟类和哺乳动物集合种群模型的开发提供了模板。并强调使用考虑群体连通性和区域动态的模型在预防原则指导下的保护管理应用中的重要性。我们的研究促进了我们对长寿殖民物种集合种群动态的理解，我们的方法为殖民生活的鸟类和哺乳动物集合种群模型的开发提供了模板。