Data from: Climatic conditions produce contrasting influences on demographic traits in a long distance Arctic migrant

The manner in which patterns of variation and interactions among demographic rates contribute to population growth rate (λ) are key to understanding how animal populations will respond to changing climatic conditions.
Migratory species are likely to be particularly sensitive to climatic conditions as they experience a range of different environments throughout their annual cycle. However, few studies have provided fully integrated demographic analyses of migratory populations in response to changing climatic conditions.
Here, we employed integrated population models (IPM) to demonstrate that the environmental conditions experienced during a short, but critical period, play a central role in the demography of a long-distance migrant, the light-bellied Brent goose (Branta bernicla hrota).
Female survival was positively associated with June North Atlantic Oscillation (NAO) values, whereas male survival was not. In contrast, breeding productivity was negatively associated with June NAO, suggesting a trade-off between female survival and reproductive success. Both adult female and adult male survival showed low temporal variation, whereas there was high temporal variation in recruitment and breeding productivity. In addition, while annual population growth was positively correlated with annual breeding productivity a sensitivity analysis revealed that population growth was most sensitive to changes in adult survival.
Our results demonstrate that the environmental conditions experienced during a relatively short-time window at the start of the breeding season play a critical role in shaping the demography of a long-distant Arctic migrant. Crucially, different demographic rates responded in opposing directions to climatic variation, emphasizing the need for integrated analysis of multiple demographic traits when understanding population dynamics.

种群统计参数（demographic rates）的变异模式与相互作用如何影响种群增长率（λ），是理解动物种群如何响应气候变化的关键所在。迁徙物种在全年生命周期中会经历多样的环境，因此对气候变化尤为敏感。然而，目前鲜有研究针对气候变化下的迁徙种群开展完整的整合式种群统计分析。本研究采用整合种群模型（integrated population models, IPM），证实了一段短暂却关键的时期内经历的环境条件，对长距离迁徙物种——浅腹黑雁（Branta bernicla hrota）的种群统计特征具有核心调控作用。雌性存活率与6月北大西洋涛动（North Atlantic Oscillation, NAO）指数呈显著正相关，而雄性存活率则无此关联。与之相反，繁殖生产力与6月NAO指数呈显著负相关，这表明雌性存活率与繁殖成功率之间存在权衡关系。成体雌雄个体的存活率均表现出较低的时间变异，而种群补充率与繁殖生产力的时间变异则较高。此外，尽管年种群增长率与年繁殖生产力呈正相关，但敏感性分析显示，种群增长率对成体存活率的变化最为敏感。本研究结果表明，繁殖季初期一段相对较短的时间窗口内经历的环境条件，对北极长距离迁徙物种的种群统计特征塑造具有关键作用。尤为重要的是，不同的种群统计参数对气候变化的响应方向截然相反，这凸显了在解析种群动态时，整合分析多种种群统计特征的必要性。