Contemporary climate change has complex effects on animal populations caused by the (non-linear) combination of multiple direct and indirect effects on individuals. These interactions make predictions of the ecological response to climate change challenging; however, predictive models are required to effectively manage wildlife populations and conserve biodiversity. Here, we demonstrate how agent-based models (ABMs) can be used to predict population responses under multiple effects of climate change. We consider the case of northern common eiders (), a culturally and ecologically important seaduck which is experiencing dramatic environmental change due to losses in Arctic sea ice. Our model shows that losses in Arctic sea ice will lead to increases in nest predation by polar bears in areas where these species are sympatric. However, climate-mediated increases in breeding propensity and clutch size could have a large positive effect on eider population size. When considered together, these effects are predicted to result in a relatively stable eider population size over a 50-year period. Additionally, assuming eider populations are influenced by climate change in the manner proposed in this study, our model suggests that future eider populations will not be more susceptible to extrinsic perturbations (e.g. severe weather events, disease outbreaks) than were historical populations. As a result, our study demonstrates increasing climatic suitability and increasing nest predation will not lead to major changes in population size in northern common eiders, and emphasizes the importance of considering multiple, interacting effects on wildlife populations experiencing climate change.

中文翻译：

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预测气候变化对北方绒鸭多重影响的结果

当代气候变化对动物种群产生复杂的影响，这是由于对个体的多种直接和间接影响的（非线性）组合造成的。这些相互作用使得预测气候变化的生态反应具有挑战性；然而，需要预测模型来有效管理野生动物种群和保护生物多样性。在这里，我们展示了如何使用基于主体的模型（ABM）来预测气候变化多重影响下的人口反应。我们以北方绒鸭为例，这是一种在文化和生态上都很重要的海鸭，由于北极海冰的消失，它正在经历巨大的环境变化。我们的模型表明，北极海冰的消失将导致北极熊在这些物种同域的地区对巢穴的捕食增加。然而，气候介导的繁殖倾向和窝产数的增加可能对绒鸭种群规模产生巨大的积极影响。如果综合考虑，这些影响预计将导致绒鸭种群数量在 50 年内保持相对稳定。此外，假设绒鸭种群以本研究中提出的方式受到气候变化的影响，我们的模型表明，未来的绒鸭种群不会比历史种群更容易受到外部扰动（例如恶劣天气事件、疾病爆发）的影响。因此，我们的研究表明，气候适宜性的提高和巢穴捕食的增加不会导致北方绒鸭种群规模的重大变化，并强调考虑对经历气候变化的野生动物种群的多重相互作用影响的重要性。