Data from: Disentangling density dependent dynamics using full annual cycle models and Bayesian model weight updating

1. Density dependence regulates populations of many species across all taxonomic groups. Understanding density dependence is vital for predicting the effects of climate, habitat loss, and/or management actions on wild populations. Migratory species likely experience seasonal changes in the relative influence of density dependence on population processes such as survival and recruitment throughout the annual cycle. These effects must be accounted for when characterizing migratory populations via population models. 2. To evaluate effects of density on seasonal survival and recruitment of a migratory species, we used an existing full annual cycle model framework for American black ducks (Anas rubripes), and tested different density effects (including no effects) on survival and recruitment. We then used a Bayesian model weight updating routine to determine which population model best fit observed breeding population survey data between1990-2014. 3. The models that best fit the survey data suggested that survival and recruitment were affected by density dependence and that density effects were stronger on adult survival during the breeding season than during the non-breeding season. 4. Analysis also suggests that regulation of survival and recruitment by density varied over time. Our results showed that different characterizations of density regulations changed every 8–-12 years (three times in the 25 year period) for our population. 5. Synthesis and applications. Using a full annual cycle modelling framework and model weighting routine will be helpful in evaluating density dependence for migratory species in both the short and long term. We used this method to disentangle Understanding the seasonal effects of density on the continental American black duck population which will allow managers to better evaluate the effects of habitat loss and potential habitat management actions throughout the annual cycle. The method here may allow researchers to hone in on the proper form and/or strength of density dependence for use in models for conservation recommendations.1. 密度制约 (density dependence) 调控着所有分类群中诸多物种的种群动态。理解密度制约，对于预测气候、栖息地丧失以及/或管理措施对野生种群的影响至关重要。迁徙物种在全年周期中，其种群过程（如存活率与种群补充量）所受密度制约的相对影响可能会随季节发生变化。在通过种群模型对迁徙种群进行特征描述时，必须纳入这类效应。 2. 为评估密度对某迁徙物种季节性存活率与种群补充量的影响，我们针对美洲黑鸭（Anas rubripes）采用了已有的全年周期模型框架，并检验了不同密度效应（包括无效应）对存活率与种群补充量的作用。随后我们借助贝叶斯模型权重更新流程，判断1990年至2014年间哪一种种群模型最适配观测得到的繁殖种群调查数据。 3. 最适配调查数据的模型显示，存活率与种群补充量均受密度制约影响，且繁殖季节的密度效应对成体存活率的作用强度高于非繁殖季节。 4. 分析结果还表明，密度对存活率与种群补充量的调控作用随时间发生变化。我们的研究结果显示，该种群的密度调控特征每8至12年便会发生一次变化（在25年的研究周期内共出现三次）。 5. 综合与应用。采用全年周期模型框架与模型权重流程，有助于短期与长期层面的迁徙物种密度制约评估。本研究借助该方法厘清了密度对美洲黑鸭大陆种群的季节性影响，这将帮助管理者更好地评估全年周期内栖息地丧失与潜在栖息地管理措施的效应。本研究所用方法可帮助研究者精准确定密度制约的恰当形式与/或强度，将其应用于服务于保护建议的种群模型之中。