Extreme events, trophic chain reactions, and shifts in phenotypic selection

Demographic consequences of rapid environmental change and extreme climatic events (ECEs) can cascade across trophic levels with evolutionary implications that have rarely been explored. Here, we show how an ECE in high Arctic Svalbard triggered a trophic chain reaction, directly or indirectly affecting the demography of both overwintering and migratory vertebrates, ultimately inducing a shift in density-dependent phenotypic selection in migratory geese. A record-breaking rain-on-snow event and ice-locked pastures led to reindeer mass starvation and a population crash, followed by a period of low mortality and population recovery. This caused lagged, long-lasting reductions in reindeer carrion numbers and resultant low abundances of Arctic foxes, a scavenger on reindeer and predator of migratory birds. The associated decrease in Arctic fox predation of goose offspring allowed for a rapid increase in barnacle goose densities. As expected according to r- and K-selection theory, the goose ..., First dataset 
The first data set includes the data to run the correlative analysis, presented in Figure 2 in the article. This was based on time series data on Svalbard reindeer abundance, a proxy of Arctic fox abundance and abundance data of barnacle geese on high Arctic Svalbard. Annual estimates of barnacle goose population size at Ny-Ålesund were obtained from the results of an integrated population model. All data are accessible in published articles or online. The percentage of occupied dens was used as a proxy of abundance of Arctic foxes, based on annual records of known den sites around Ny‐Ålesund with pup production during summer (Fuglei et al. 2003) and were obtained from MOSJ (2021). Data of reindeer abundances (population counts) were available from Supplementary Information Figure S1 in Hansen et al. (2019). Data of goose abundance (total population size estimated with an integrated population model) were obtained from (Layton-Matthews et al. 2019). Please see respective ..., , # Extreme events, trophic chain reactions, and shifts in phenotypic selection

[https://doi.org/10.5061/dryad.hhmgqnknq](https://doi.org/10.5061/dryad.hhmgqnknq)

Two datasets are enclosed, the first to perform the correlative analyses (Figure 2), the second to estimate the demography-trait relationships (Figure 3) and estimate density-dependent phenotypic selection (Figure 4).

## First dataset: Correlative analysis

Time series data of a proxy of Arctic fox abundance, wild Svalbard reindeer abundance, and barnacle geese abundance data. All data are accessible in published articles or online. The percentage occupied dens was used as a proxy of abundance Arctic foxes, based on annual records of known den sites around Ny‐Ålesund with pup production during summer (Fuglei et al. 2003) and were obtained from MOSJ (2021). Data of reindeer abundances (population counts) were available from Supplementary Information Figure S1 in Hansen et al. (2019). Data of goose abundances (total population ...

极端气候事件（Extreme Climatic Events, ECEs）与快速环境变化所带来的种群统计学效应可沿营养级联传递，其蕴含的演化意义此前极少被探索。本文揭示了北极斯瓦尔巴（Svalbard）地区的一场极端气候事件如何触发营养级联反应，直接或间接影响越冬与洄游脊椎动物的种群动态，最终引发洄游雁类密度依赖型表型选择（density-dependent phenotypic selection）的转变。一场破纪录的雪面降雨事件与冰封草场导致驯鹿大规模饿死并出现种群骤降，随后迎来一段低死亡率与种群恢复的时期。这一事件滞后且长期地降低了驯鹿腐尸的数量，进而导致以驯鹿腐尸为食、同时捕食洄游鸟类的北极狐种群丰度下降。北极狐对雁类后代的捕食压力随之降低，使得藤壶雁（barnacle goose）的种群密度快速上升。依据r-与K-选择理论（r- and K-selection theory）的预期，雁类……，首个数据集
首个数据集包含用于开展相关性分析的数据，对应论文中的图2。该数据集基于北极高纬度斯瓦尔巴地区的斯瓦尔巴驯鹿种群丰度时间序列数据、北极狐种群丰度替代指标数据，以及藤壶雁种群丰度数据。在新奥尔松（Ny-Ålesund）地区的藤壶雁种群年度规模估算值，来自整合种群模型（integrated population model）的研究结果。所有数据均可从已发表论文或公开在线平台获取。以繁殖穴占据率作为北极狐种群丰度的替代指标，该数据基于新奥尔松周边已知繁殖穴的年度记录（包含夏季幼崽生产情况，Fuglei等人2003年研究），源自MOSJ（2021）。驯鹿种群丰度数据（种群计数数据）来自Hansen等人（2019年）研究的补充信息图S1。藤壶雁种群丰度数据（通过整合种群模型估算的总种群规模）源自Layton-Matthews等人（2019年）的研究。详见相关……，# 极端事件、营养级联反应与表型选择偏移
[https://doi.org/10.5061/dryad.hhmgqnknq](https://doi.org/10.5061/dryad.hhmgqnknq)
本数据集包含两套数据：第一套用于开展相关性分析（对应图2），第二套用于估算种群动态-性状关系（对应图3）以及密度依赖型表型选择（对应图4）。

## 首个数据集：相关性分析
包含北极狐种群丰度替代指标、斯瓦尔巴野生驯鹿种群丰度，以及藤壶雁种群丰度的时间序列数据。所有数据均可从已发表论文或公开在线平台获取。以繁殖穴占据率作为北极狐种群丰度的替代指标，该数据基于新奥尔松周边已知繁殖穴的年度记录（包含夏季幼崽生产情况，Fuglei等人2003年研究），源自MOSJ（2021）。驯鹿种群丰度数据（种群计数数据）来自Hansen等人（2019年）研究的补充信息图S1。藤壶雁种群丰度数据（通过整合种群模型估算的总种群规模）相关内容源自Layton-Matthews等人（2019年）的研究。