Data from: Managing individual nests promotes population recovery of a top predator

Threatened species are managed using diverse conservation tactics implemented at multiple scales ranging from protecting individuals, to populations, to entire species. Individual protection strives to promote recovery at the population- or species-level, although this is seldom evaluated. After decades of widespread declines, bald eagles, Haliaeetus leucocephalus, are recovering throughout their range due to legal protection and pesticide bans. However, like other raptors, their recovery remains threatened by human activities. Bald eagle nests are commonly managed using buffer zones to minimize human disturbance, but the benefits of this practice remain unquantified. Within Voyageurs National Park (VNP), Minnesota, USA, managers have monitored bald eagle populations for over 40 years, and since 1991, have protected at-risk nests from human disturbance using buffer zones (200 and 400 m radius). We aimed to (1) quantify the recovery of bald eagles in VNP (1973–2016), and (2) provide a first-ever evaluation of the individual- and population-level effects of managing individual nests. To do so, we developed Bayesian Integrated Population Models combining observations of nest occupancy and reproductive output (metrics commonly collected for raptors) to estimate nest-level probabilities of occupancy, nest success, and high productivity (producing ≥2 nestlings), as well as population-level estimates of abundance and growth. The breeding population of bald eagles at VNP increased steadily from <10 pairs in the late 1970s to 48 pairs by 2016. At the nest-level, management significantly improved occupancy and success. At the population-level, management led to 8% and 13% increases in nest success and productivity rates, respectively, resulting in a 37% increase in breeding pair abundance. Synthesis and applications. There is a clear need to evaluate how management approaches at multiple scales assist in species recovery. Our study uses an Integrated Population Model to reveal the population-level benefits of a widely used, individual-based management action (protecting nests using buffer zones) on a recovering raptor.受威胁物种的保护管理采用多尺度实施的多样化保护策略，涵盖个体保护、种群保护乃至整个物种种群保护的范畴。尽管个体保护旨在推动种群或物种种群的恢复，但此类措施的实施效果却鲜有评估。 历经数十年的大范围种群衰退后，白头海雕（Haliaeetus leucocephalus）凭借法律保护与农药禁用政策，在其整个分布范围内逐步实现种群恢复。然而与其他猛禽类群一样，其种群恢复进程仍面临人类活动的威胁。当前白头海雕的巢域通常通过设置缓冲区以降低人类干扰的方式进行管理，但该措施的实施效益尚未得到量化评估。 美国明尼苏达州沃亚楚格斯国家公园（Voyageurs National Park, VNP）的管理人员已对白头海雕种群开展了40余年的监测工作，自1991年起，他们通过设置半径200米与400米的缓冲区，对处于风险中的巢域实施人类干扰防护。本研究旨在达成两大目标：（1）量化分析1973年至2016年间VNP地区白头海雕的种群恢复情况；（2）首次评估个体巢域管理对种群与个体层面的影响效应。为此，我们构建了贝叶斯整合种群模型（Bayesian Integrated Population Models），结合猛禽监测中常用的巢域占用率与繁殖产出两类观测指标，以估算巢域层面的占用概率、巢域成功率以及高繁殖力（产出≥2只雏鸟）概率，同时获取种群层面的种群数量与增长速率估算值。 VNP地区白头海雕的繁殖种群数量从20世纪70年代末的不足10对，稳步增长至2016年的48对。在巢域层面，管理措施显著提升了巢域占用率与繁殖成功率；在种群层面，该管理措施分别使巢域成功率与繁殖生产力提升了8%与13%，最终推动繁殖配对种群数量增长37%。 研究总结与应用启示。当前亟需评估多尺度管理策略对物种恢复的辅助作用机制。本研究通过整合种群模型，揭示了广泛应用的个体导向型管理措施——即通过缓冲区保护巢域——对正在恢复的猛禽种群所带来的种群层面效益。