Continent-wide drivers of spatial synchrony in breeding demographic structure across wild great tit populations

Variation in age structure influences population dynamics, yet we have limited understanding of the spatial scale at which its fluctuations are synchronised between populations. Using 32 great tit populations, spanning 4○W–33○E and 35–65○N involving >130,000 birds across 67 years, we quantify spatial synchrony in breeding demographic structure (subadult vs. adult breeders) and its drivers. We show that larger clutch sizes, colder winters, and larger beech crops lead to younger populations. We report distance-dependent synchrony of demographic structure, maintained at approximately 650km. Despite covariation with demographic structure, we do not find evidence for environmental variables influencing the scale of synchrony, except for beech masting. We suggest that local ecological and density-dependent dynamics impact how environmental variation interacts with demographic structure, influencing estimates of the environment’s effect on synchrony. Our analyses demonstrate the operation o..., Study systems and data collection The great tit Parus major is a passerine bird found in mixed woodlands across much of the Western Palearctic. Their reproductive lifespan ranges from 1–9, averaging 1.8 years (Bouwhuis et al. 2009; Woodman et al. 2022). Although there are some continuous changes with age (Bouwhuis et al. 2009), the main age effects on individual-level traits and population processes are captured by two age-classes: 1-year-olds (hereafter subadults) and older (hereafter adults, Gosler 1993; Harvey et al. 1979; Perrins 1979; Gamelon et al. 2016, 2019; Woodman et al. 2022). Great tits generally undertake one breeding attempt during a single annual breeding season April–June (in some parts of their range second clutches can occur, Verhulst 1998; Visser et al. 2003). Data used here are from 32 populations, the geographical range of which represents a large part of the species’ breeding range (Sullivan et al. 2009). Generally, data collection at these sites included regular v..., , # Continent-wide drivers of spatial synchrony in breeding demographic structure across wild great tit populations [Access this dataset on Dryad](https://doi.org/10.5061/dryad.k0p2ngfgg) Presented here is the raw data (\"bred_dem_synchrony.RData\") and annotated R Script (\"Continent-wide drivers of spatial synchrony in breeding demographic structure across wild great tit populations.R\") needed to run analyses for the project \"Continent-wide drivers of spatial synchrony in breeding demographic structure across wild great tit populations\". ## Description of the data and file structure \"bred_dem_synchrony.RData\": R-data file needed to run analyses. Descriptions of the three datasets within this file are found in the R script, and also below. 1. \"bred_dem_variables\" = Base data for annual breeding demographic structure variables of great tit populations. Only includes populations with annual population size equal or greater than 20 individuals and where 25% or more of individuals have be...年龄结构的变异会对种群动态产生影响，但当前学界对不同种群间年龄结构波动的同步空间尺度的认知仍较为有限。本研究依托覆盖西经4°至东经33°、北纬35°至65°的32个大山雀种群，涵盖67年间超过13万只个体，对繁殖种群年龄结构（亚成体与成体繁殖个体）的空间同步性及其驱动因子进行了量化分析。研究结果显示，更大的窝卵数、更寒冷的冬季以及更丰沛的山毛榉结实量会促使种群结构更年轻化。我们发现种群繁殖年龄结构的同步性呈现距离依赖性，其维持的临界距离约为650千米。尽管种群年龄结构与部分环境变量存在协变关系，但除山毛榉结实事件外，我们未发现其他环境变量对同步性尺度存在显著影响。我们推测，局域生态过程与密度依赖动态会调控环境变异与种群年龄结构的互作关系，进而影响环境因子对种群同步性影响的评估精度。本研究分析证实了[原文此处存在截断]。 # 野生大山雀种群繁殖年龄结构空间同步性的大陆尺度驱动因子 研究系统与数据采集 大山雀（great tit, *Parus major*）是雀形目鸟类，广泛分布于古北界西部的混交林生境中。其繁殖寿命为1–9年，平均寿命1.8年（Bouwhuis et al. 2009; Woodman et al. 2022）。尽管个体随年龄存在一些连续的性状变化（Bouwhuis et al. 2009），但种群水平的个体性状与种群过程的主要年龄效应可通过两个年龄组进行划分：1龄个体（下文简称亚成体）与成体（下文简称成年个体，Gosler 1993; Harvey et al. 1979; Perrins 1979; Gamelon et al. 2016, 2019; Woodman et al. 2022）。大山雀通常在每年的繁殖季（4–6月）仅进行一次繁殖尝试，部分分布区内的种群可产出第二窝卵（Verhulst 1998; Visser et al. 2003）。本研究使用的数据集来自32个种群，其地理范围覆盖了该物种繁殖分布区的绝大部分区域（Sullivan et al. 2009）。通常，这些研究站点的数据采集工作包括常规的[原文此处存在截断]。 [可在Dryad获取本数据集](https://doi.org/10.5061/dryad.k0p2ngfgg) 本数据集包含复现研究"野生大山雀种群繁殖年龄结构的大陆尺度同步性驱动因子"所需的原始数据（"bred_dem_synchrony.RData"）与带注释的R脚本（"Continent-wide drivers of spatial synchrony in breeding demographic structure across wild great tit populations.R"）。 ## 数据与文件结构说明 "bred_dem_synchrony.RData"：用于运行分析的R数据文件。该文件内包含的三个数据集的说明可在R脚本及下文查阅。 1. "bred_dem_variables"：大山雀种群年度繁殖年龄结构变量的基础数据。仅包含年度种群规模不低于20只个体，且25%及以上的个体有[原文此处存在截断]。