RAPID: Impact of extreme heat-induced mortality on avian cooperative social systems

热浪、干旱和风暴等极端天气事件可能对当地生态系统造成严重后果，引发人口减少或活动范围转移。虽然生理和形态上的适应可能有助于缓冲动物对生态变化的影响，但人们对社会性（一种帮助动物应对不可预测或恶劣环境的特征）如何减轻（或加剧）突然的、长期的气候事件的后果知之甚少。今年，南澳大利亚的野生动物受到持续热浪的影响，导致附近动物群落死亡。该项目将利用收集到的两种群居鸟类——锦绣尾鹩莺和紫背尾鹩莺——的社会行为的长期数据，来研究在极端环境压力下，社会群体成员身份是否能提高生存结果。这项工作将有助于阐明不同的社会系统和社区如何应对未来的气候事件，通过捕捉两个社会物种对这种天气事件的整体和个人层面的反应，并具有不同程度的社会参与。更广泛的影响将包括培训学生和一名博士后研究员，并向更广泛的非科学界传播研究结果，以帮助普通受众了解极端天气事件如何影响动物的自然种群。澳大利亚最近经历了许多灾难性的干旱、热浪和火灾，这些都导致了高温导致的鸟类死亡事件，对人口反应的评估可以帮助人们了解日益常见的极端气候事件对人口的影响。以前的工作主要集中在临界温度、人口统计学和形态变化上；没有研究涉及合作繁殖——一种与环境变化有关的行为。该项目将解决两个研究目标：1)确定在群体规模方面是否存在差异生存；2)确定在两种不同的合作繁殖系统中，灾难性死亡对后续社会结构和动态的影响。在2019年12月热浪到来之前的几天里，对锦绣尾鹩莺和紫背尾鹩莺的群体组成和繁殖成功率进行了最后一次监测。该项目将包括秋季的一次调查，以评估存活率和种群组成，以及跨越繁殖前和繁殖季节的第二次旅行，以评估人口变化对社会群体力量和结构的影响。在每次旅行中，将通过重新观察个人独特的颜色带来评估社会联系和个人存在。未被捆绑的个体将被捕获并捆绑，并评估它们在种群中的社会地位。这些方法将使2019年的社会行为与高温事件的生存联系起来，并允许团队成员随后评估2020年繁殖季节的分散行为、群体结构和繁殖成功如何受到人口变化的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Extreme weather events such as heatwaves, droughts, and storms can have dire consequences for local ecosystems, sparking population decline or range shifts. While physiological and morphological adaptations may help buffer animals against ecological shifts, little is known about how sociality—a trait which can help animals cope with unpredictable or harsh environments—might mitigate (or exacerbate) the consequences of abrupt, prolonged climatic events. This year, wildlife in South Australia were subject to extended heatwaves which resulted in mortality in nearby animal communities. This project will take advantage of long-term data collected on social behavior of two social species of birds - splendid and purple-backed fairywrens - to ask whether social group membership can improve survival outcomes following extreme environmental stressors. This work will help elucidate how different social systems and communities will respond to climatic events in the future by capturing both the population-wide and individual level response to this weather event in two social species with varying degrees of social participation. Broader impacts will include training of students and a post-doctoral researcher and dissemination of findings to the broader non-scientific community to help general audiences understand how extreme weather events impact natural populations of animals. Australia has recently experienced numerous catastrophic droughts, heat waves, and fires that have led to heat-induced avian mortality events where assessment of population responses could provide insight on the impact of increasingly common extreme climatic events on populations. Previous work has focused on critical temperature, demography, and morphological changes; no work has addressed cooperative breeding — a behavior linked to environmental variability. This project will address two research aims: 1) Determine whether differential survival occurred with respect to group size and 2) Determine the impact of catastrophic mortality on subsequent social structure and dynamics in two different cooperatively breeding systems. Group composition and reproductive success of both splendid and purple-backed fairywrens were last monitored in the days immediately prior to the December 2019 heatwave. This project will consist of a survey in autumn to assess survival and population composition, and a second trip spanning the pre-breeding and breeding seasons to assess the impact of demographic changes on the strength and structure of social groups. During each trip social associations and individual presence will be assessed through re-sighting of individually unique color bands. Unbanded individuals will be captured and banded, and their social status within the population assessed. These methods will allow 2019 social behavior to be linked to survival of the heat event, and allow team members to subsequently assess how dispersal behavior, group structure, and reproductive success in the 2020 breeding season is impacted by demographic changes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.