Data from: Modeling effects of nonbreeders on population growth estimates

Adult individuals that do not breed in a given year occur in a wide range of natural populations. However, such nonbreeders are often ignored in theoretical and empirical population studies, limiting our knowledge of how nonbreeders affect realized and estimated population dynamics and potentially impeding projection of deterministic and stochastic population growth rates. We present and analyse a general modelling framework for systems where breeders and nonbreeders differ in key demographic rates, incorporating different forms of nonbreeding, different life histories and frequency-dependent effects of nonbreeders on demographic rates of breeders. Comparisons of estimates of deterministic population growth rate, λ, and demographic variance, math formula, from models with and without distinct nonbreeder classes show that models that do not explicitly incorporate nonbreeders give upwardly biased estimates of math formula, particularly when the equilibrium ratio of nonbreeders to breeders, math formula, is high. Estimates of λ from empirical observations of breeders only are substantially inflated when individuals frequently re-enter the breeding population after periods of nonbreeding. Sensitivity analyses of diverse parameterizations of our model framework, with and without negative frequency-dependent effects of nonbreeders on breeder demographic rates, show how changes in demographic rates of breeders vs. nonbreeders differentially affect λ. In particular, λ is most sensitive to nonbreeder parameters in long-lived species, when math formula, and when individuals are unlikely to breed at several consecutive time steps. Our results demonstrate that failing to account for nonbreeders in population studies can obscure low population growth rates that should cause management concern. Quantifying the size and demography of the nonbreeding section of populations and modelling appropriate demographic structuring is therefore essential to evaluate nonbreeders' influence on deterministic and stochastic population dynamics.特定年份未参与繁殖的成年个体广泛存在于各类自然种群中。然而这类非繁殖个体常被理论与实证种群研究所忽略，这不仅限制了我们对非繁殖个体如何影响实际种群动态与估算种群动态的认知，还可能阻碍确定性与随机性种群增长率的预测工作。 我们针对繁殖个体与非繁殖个体在关键种群统计率上存在差异的种群系统，提出并分析了一套通用建模框架，该框架纳入了多种非繁殖形式、不同生活史类型，以及非繁殖个体对繁殖个体种群统计率的频率依赖效应。 对比包含与不包含明确非繁殖个体类别的模型所估算的确定性种群增长率λ与种群统计方差（math formula）后发现，未明确纳入非繁殖个体的模型会高估math formula，尤其当非繁殖个体与繁殖个体的平衡比math formula较高时。若个体在经历一段非繁殖期后频繁重新进入繁殖种群，仅基于繁殖个体的实证观测所估算的λ值会被显著高估。 我们对该建模框架的多种参数化方案（包含与不包含非繁殖个体对繁殖个体种群统计率的负频率依赖效应）开展敏感性分析，结果揭示了繁殖个体与非繁殖个体的种群统计率变化如何差异化影响λ值。具体而言，在长寿物种中、当math formula时，以及当个体难以在连续多个时间步内参与繁殖时，λ对非繁殖个体参数最为敏感。 我们的研究结果表明，在种群研究中未纳入非繁殖个体的考量，会掩盖本应引起管理关注的低种群增长率情况。因此，量化种群中非繁殖个体的数量与种群统计特征，并构建合适的种群统计结构模型，对于评估非繁殖个体对确定性与随机性种群动态的影响至关重要。