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众多物种种群的动态。明晰密度制约机制，对于预测气候变化、栖息地丧失及/或管理措施对野生物种种群的影响至关重要。迁徙物种在其年度生活周期中，密度制约对种群过程如存活与补充的相对影响可能会随季节发生变化。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. 为评估密度对某一迁徙物种种季存活与补充的影响，我们采用了针对美洲黑鸭（Anas rubripes）的现有全年度周期模型框架，并检验了不同的密度效应（包括无效应）对存活率与补充量的作用。随后，我们通过贝叶斯模型权重更新程序，确定了1990年至2014年间最适配观测到的繁殖种群调查数据的种群模型。 3. 最适配调查数据的模型表明，存活率与补充量均受到密度制约的调控，且繁殖季节的密度制约效应对成体存活率的影响强于非繁殖季节。 4. 分析还显示，密度对存活率与补充量的调控作用随时间发生变化。我们的研究结果表明，该种群的密度调控特征每8至12年就会发生一次变化（在25年的研究周期内共出现三次）。 5. 综合与应用。采用全年度周期建模框架与模型权重更新程序，有助于在短期与长期尺度下评估迁徙物种的密度制约效应。我们借助该方法厘清了密度对美洲黑鸭大陆种群的季节影响，这将帮助管理者更好地评估整个年度周期内的栖息地丧失与潜在栖息地管理措施的效应。本研究提出的方法可助力研究者精准确定密度制约的适宜形式与/或强度，以便将其应用于保育建议相关的模型构建中。