An integrated population model to project viability of a northern bobwhite population in Ohio [DATA]

Increased variation in interannual weather due to climate change can exert a powerful influence on the population dynamics of a species. Understanding the influence of severe weather is important for managing weather-sensitive species. While best management practices target vital rates that are affected by weather, focusing on a single vital rate may not be sufficient if other vital rates are secondarily limiting. A comprehensive modeling framework to forecast future population dynamics while incorporating weather scenarios and vital rate variation within observed ranges that can be affected by management actions are necessary. A potential approach is to combine an integrated population model (IPM) with a population viability analysis (PVA) to generate novel insights about population dynamics. We used the northern bobwhite (Colinus virginianus), a rapidly declining gamebird sensitive to snowfall along the northern extents of the species’ range, to demonstrate the utility of a coupled IPM-PVA framework for projecting the response of a population to weather, management, and changes in vital rates. We created an IPM using two sources of count data spanning seven years, five years of winter survival data, and two years of breeding season demographics for a declining bobwhite population in southwestern Ohio during 2007–2015. Quasi-extinction probability at the end of the decadal projection during 2019–2029 was 0.384–0.410 for mild, average, and severe winter weather scenarios. Quasi-extinction probability declined to 0.326 with 20% improvement in nest success and summer survival rates. A concurrent 20% increase in winter survival further reduced quasi-extinction probability to 0.263, which is a ~36% reduction in quasi-extinction probability compared to the baseline scenario with no changes in vital rates. These results suggest that long-term viability of this population may depend on extensive management of winter habitat to improve survival but will also require management actions to improve fecundity after severe winters. Our modeling approach demonstrated how IPMs can be used to project population responses to future weather conditions and overcome some of the pitfalls of traditional PVA. The coupled framework presented here can serve as a tool for managers to make climate informed management decisions.

气候变化导致的年际天气变异性加剧，可对物种种群动态产生显著影响。明晰极端天气的影响，对管护对天气敏感的物种而言至关重要。尽管最佳管护实践通常聚焦于受天气影响的生命率，但若其他生命率存在次级限制效应，仅关注单一生命率或不足以达成管护目标。亟需构建一套综合建模框架，在纳入天气情景、以及管护措施可影响范围内的观测生命率变异的同时，预测未来种群动态。一种可行的方案是将集成种群模型（integrated population model, IPM）与种群生存力分析（population viability analysis, PVA）相结合，以获得关于种群动态的全新认知。本研究以北部翎鹑（Colinus virginianus）——一种在其分布北界对降雪敏感且种群正快速衰退的猎用鸟类——为研究对象，验证了耦合IPM-PVA框架在预测种群对天气、管护措施及生命率变化响应方面的实用性。我们利用2007-2015年间俄亥俄州西南部一处衰退翎鹑种群的两类七年期计数数据、五年期越冬存活率数据以及两年期繁殖期种群统计数据，构建了集成种群模型。在2019-2029年的十年预测期末，轻度、中等及极端冬季天气情景下的准灭绝概率为0.384~0.410。若繁殖成功率与夏季存活率提升20%，准灭绝概率将降至0.326。同步提升越冬存活率20%，可进一步将准灭绝概率降至0.263，相较于生命率无变化的基准情景，准灭绝概率降幅约达36%。上述结果表明，该种群的长期生存力或依赖于通过大规模冬季生境管护提升存活率，同时也需要在极端冬季后采取管护措施以提高繁殖力。本研究的建模方法阐明了集成种群模型如何用于预测种群对未来天气条件的响应，并弥补了传统种群生存力分析的部分缺陷。本文提出的耦合框架可作为管护人员制定气候适配型管护决策的工具。