Improved monitoring and associated inferential tools to efficiently identify declining bird populations, particularly of rare or sparsely distributed species, is key to informed conservation and management across large spatiotemporal regions. We assess abundance trends for 106 bird species in a network of eight forested national parks located within the northeast United States from 2006 to 2019 using a novel hierarchical model. We develop a multispecies, multiregion, removal-sampling model that shares information across species and parks to enable inference on rare species and sparsely sampled parks and to evaluate the effects of local forest structure. Trends in bird abundance over time varied widely across parks, but species showed similar trends within parks. Three parks (Acadia National Park and Marsh-Billings-Rockefeller and Morristown National Historical Parks [NHP]) decreased in bird abundance across all species, while three parks (Saratoga NHP and Roosevelt-Vanderbilt and Weir-Farm National Historic Sites) increased in abundance. Bird abundance peaked at medium levels of basal area and high levels of percent forest and forest regeneration, with percent forest having the largest effect. Variation in these effects across parks could be a result of differences in forest structural stage and diversity. By sharing information across both communities and parks, our novel hierarchical model enables uncertainty-quantified estimates of abundance across multiple geographical (i.e., network, park) and taxonomic (i.e., community, guild, species) levels over a large spatiotemporal region. We found large variation in abundance trends across parks but not across bird guilds, suggesting that local forest condition might have a broad and consistent effect on the entire bird community within a given park. Research should target the three parks with overall decreasing trends in bird abundance to further identify what specific factors are driving observed declines across the bird community. Understanding how bird communities respond to local forest structure and other stressors (e.g., pest outbreaks, climate change) is crucial for informed and lasting management.

中文翻译：

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受保护森林的鸟类丰度趋势不同，但鸟类公会没有

改进监测和相关推理工具以有效识别鸟类数量下降，尤其是稀有或分布稀疏的物种，是大时空区域知情保护和管理的关键。我们使用新的分层模型评估了 2006 年至 2019 年位于美国东北部的八个森林国家公园网络中 106 种鸟类的丰度趋势。我们开发了一个多物种、多区域、移除采样模型，该模型在物种和公园之间共享信息，以推断稀有物种和稀疏采样的公园，并评估当地森林结构的影响。随着时间的推移，不同公园的鸟类数量趋势差异很大，但公园内的物种表现出相似的趋势。三个公园（阿卡迪亚国家公园和马什-比林斯-洛克菲勒和莫里斯敦国家历史公园 [NHP]）所有物种的鸟类数量都减少了，而三个公园（萨拉托加 NHP 和罗斯福-范德比尔特以及威尔农场国家历史遗址）的数量增加了. 鸟类丰度在中等水平的基础面积和高水平的森林和森林更新率达到峰值，其中森林百分比的影响最大。不同公园的这些影响的差异可能是森林结构阶段和多样性不同的结果。通过在社区和公园之间共享信息，我们新颖的分层模型能够对大时空区域内多个地理（即网络、公园）和分类（即社区、行会、物种）级别的丰度进行不确定性量化估计。我们发现公园之间的丰度趋势存在很大差异，但鸟类公会之间没有，这表明当地森林状况可能对给定公园内的整个鸟类群落产生广泛而一致的影响。研究应针对鸟类数量总体呈下降趋势的三个公园，以进一步确定哪些具体因素导致鸟类群落观察到的下降。了解鸟类社区如何应对当地森林结构和其他压力因素（例如，虫害爆发、气候变化）对于知情和持久的管理至关重要。研究应针对鸟类数量总体呈下降趋势的三个公园，以进一步确定哪些具体因素导致鸟类群落观察到的下降。了解鸟类社区如何应对当地森林结构和其他压力因素（例如，虫害爆发、气候变化）对于知情和持久的管理至关重要。研究应针对鸟类数量总体呈下降趋势的三个公园，以进一步确定哪些具体因素导致鸟类群落观察到的下降。了解鸟类社区如何应对当地森林结构和其他压力因素（例如，虫害爆发、气候变化）对于知情和持久的管理至关重要。