Demographic consequences of phenological asynchrony for North American songbirds

Changes in phenology in response to ongoing climate change have been observed in numerous taxa around the world. Differing rates of phenological shifts across trophic levels have led to concerns that ecological interactions may become increasingly decoupled in time, with potential negative consequences for populations. Despite widespread evidence of phenological change and a broad body of supporting theory, large-scale multi-taxa evidence for demographic consequences of phenological asynchrony remains elusive. Using data from a continental-scale bird banding program, we assess the impact of phenological dynamics on avian breeding productivity in 41 species of migratory and resident North American birds breeding in and around forested areas. We find strong evidence for a phenological optimum where breeding productivity decreases in years with both particularly early or late phenology and when breeding occurs early or late relative to local vegetation phenology. Moreover, we demonstrate t..., Bird capture data were collected as part of the Monitoring Avian Productivity and Survivorship (MAPS) program, a collaborative long-term bird-banding project operating across North America. Data were obtained from 179 banding stations. Each banding station consisted of 6–20 mist nets operated approximately every ten days beginning as early as May 1 (start date varying slightly by location) through August 8 (ordinal dates 121–220 in a non-leap year), which span the breeding season for most birds in North America. Only species/locations/years with at least 15 total captures, at least 5 of those being juveniles, species/locations with at least 5 years of data, and species with at least 15 locations/years of data were considered.
Bird breeding phenology was calculated using the capture dates of juvenile birds at MAPS stations. This measure of breeding phenology is indicative of the time of year at which young birds are fledging. For each species, at each location, in each year, our metric o..., Data from the Monitoring Avian Productivity and Survivorship (MAPS) program are curated and managed by The Institute for Bird Populations and were queried from the MAPS database on 2019-10-16.

全球范围内诸多生物类群均已观测到物候随持续气候变化发生改变。不同营养级间的物候偏移速率存在差异，这引发学界广泛担忧：生态相互作用可能在时间维度上愈发解耦，进而对种群产生潜在负面影响。尽管已有大量关于物候变化的研究及相关支撑理论，但针对物候异步性所带来的种群人口统计学效应的大尺度多类群实证证据仍较为稀缺。
本研究依托北美大陆尺度的鸟类环志项目所获数据，针对栖息于林区及周边的41种迁徙性与定居性北美鸟类，评估了物候动态对其繁殖生产力的影响。研究发现存在显著的物候最优区间：在物候过早或过晚的年份，以及繁殖时间相对于当地植被物候过早或过晚时，鸟类的繁殖生产力均会下降。此外，本研究证实了[原文此处内容未完整呈现]。
本次研究使用的鸟类捕获数据源自《监测鸟类生产力与存活率》（Monitoring Avian Productivity and Survivorship，简称MAPS）项目，该项目是一项覆盖北美地区的协作式长期鸟类环志计划。研究数据来自179个环志站点，每个站点布设6至20张雾网，采样周期约为每10天一次，采样时段为5月1日（各站点起始日期略有微调）至8月8日（平年对应的序数日期为121至220），该时段覆盖北美多数鸟类的繁殖季。本研究仅纳入满足以下条件的类群/站点/年份数据：总捕获量不少于15只，其中幼鸟捕获量至少5只；对应类群与站点的有效数据时长不少于5年；对应类群的有效站点/年份数据不少于15组。
鸟类繁殖物候通过MAPS站点内幼鸟的捕获日期进行计算，该指标可反映幼鸟离巢的年度时间节点。针对每一物种、每一站点及每一年份，本研究的物候指标为[原文此处内容未完整呈现]。
《监测鸟类生产力与存活率》（MAPS）项目的数据由鸟类种群研究所（The Institute for Bird Populations）负责整理与管理，本研究于2019年10月16日从MAPS数据库中调取了相关数据。