IntBIO COLLABORATIVE RESEARCH: Integrating trait diversity across hierarchical scales to predict biological resilience in an era of extreme environmental change

极端气候事件，如干旱或野火，可能会频繁发生和/或同时发生。在未来几十年里，这些极端事件可能会更频繁地发生，对自然和人类景观的影响可能会比单独发生极端事件时更严重。2015年和2016年，非洲南部许多地区遭受了复合极端天气的影响，干旱和大量使用野生动物导致国家公园的植被覆盖大幅下降，野生动物大量死亡。许多地区尚未完全恢复。复合极端天气后的生态系统恢复对于维持景观提供的重要服务至关重要，如野生动物栖息地、粮食生产和碳储存。尽管越来越多的证据表明，生态系统内生物的多样性（即生物多样性）可能是关键，但极端事件后恢复背后的机制尚不清楚。该奖项将实验性地在南非热带稀树大草原施加复合极端条件，并将测量结果纳入计算机模型，以了解植物生命多样性如何控制复合极端条件后的生态系统恢复。该项目所创造的信息和工具对于土地管理者和决策者通过促进生物多样性来最大限度地发挥公共和私人土地的恢复潜力非常重要。此外，该项目将为不同人群（南非当地利益相关者、高中生、本科生和研究生以及博士后学者）提供重要的培训和教育机会，并将优先促进科学领域的多样性、公平性和包容性。目前，生物多样性对生态系统恢复（即恢复力）的重要性在群落水平上得到了认识，但物种多样性的机制将这些概念扩展到其他空间和层次尺度上的机制尚未得到很好的理解。有机体特征为理解这些机制提供了一个有用的框架，因为生理、形态和解剖特征的协调决定了个体对环境的反应；这有助于利用第一性原理从生物体扩展到种群、群落和生态系统。本研究将首先通过研究植物性状多样性（如功能分散）的方法，将生物多样性-恢复力的概念扩展到简单的物种多样性之外。其次，它将扩大生物多样性与恢复力之间的关系，从个体生物，到种群和社区，再到整个生态系统。为此，本项目将在南非热带稀树草原单独或联合实施极端干旱、极端放牧和极端火灾，并确定(1)处理前、处理中和处理后功能性状的多样性，与(2)处理期间和处理后个人、种群、社区和生态系统的反应相联系。然后将使用经验数据来参数化和基准化一个机械人口植被模型，以将这些影响的推断扩展到更长的时间框架和更广泛的生物多样性情景。本项目将解决的三个首要问题是：(1)不同层次尺度上的多样性如何控制扰动后生物功能的恢复力？(2)扰动如何影响多层次尺度的生物多样性？(3)多样性和弹性如何随频率和复合扰动而变化？该项目由生物科学理事会的新兴前沿和促进竞争性研究的既定计划（EPSCoR）共同资助。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 climate events, such as drought or wildfire, may occur in high frequency and/or in tandem. These extremes are likely to occur more frequently over the coming decades and will likely have more severe effects on natural and human landscapes than when extreme events occur alone. Many parts of southern Africa suffered the effects of compound extremes in 2015 and 2016 when drought and heavy wildlife use caused substantial declines in vegetative cover and mass wildlife mortality in national parks. Many areas are yet to fully recover. Ecosystem recovery after compound extremes is critical for maintaining important services that landscapes provide, such as wildlife habitat, food production, and carbon storage. The mechanisms behind recovery after extreme events are not well understood, although there is mounting evidence that the diversity of organisms (i.e., biodiversity) within ecosystems may be key. This award will experimentally impose compound extremes in a South African savanna and incorporate measured outcomes into computer models to understand how diversity of plant life controls ecosystem recovery after compound extremes. The information and tools created by this project will be important for land managers and policy makers to maximize the recovery potential of public and private lands through the promotion of biodiversity. Additionally, this project will provide important training and education opportunities for a diverse assemblage of people (local South African stakeholders, high school, undergraduate and graduate students, and postdoctoral scholars), and will prioritize advancement of diversity, equity, and inclusion in the sciences.Currently, the importance of biodiversity for ecosystem recovery (i.e., resilience) is recognized at the community level, but the mechanisms underlying species diversity that can extend these concepts to other spatial and hierarchical scales are not well understood. Organismal traits provide a useful framework for understanding these mechanisms because the coordination of physiological, morphological, and anatomical characteristics determine the response of individuals to their environment; this facilitates scaling from organisms to populations, communities, and ecosystems using first principles. This study will first extend biodiversity-resilience ideas beyond simple species diversity by using methods to examine diversity of plant traits (e.g., functional dispersion). Second, it will scale biodiversity-resilience relationships from individual organisms, through populations and communities, to entire ecosystems. To these ends, this project will experimentally impose extreme drought, extreme grazing, and extreme fire, singly and in combination, in a South African savanna and determine (1) diversity of functional traits before, during, and after treatments to link with (2) responses of individuals, populations, communities, and the ecosystem during and after treatments. Empirical data will then be used to parameterize and benchmark a mechanistic demographic vegetation model to expand the inference of these effects to longer time frames and a wider range of biodiversity scenarios. The three overarching questions this project will address are: (1) How does diversity at different hierarchical scales control resilience of biological function after perturbations? (2) How do perturbations affect biodiversity at multiple hierarchical scales? (3) How does diversity and resilience change with frequency and compound perturbations?This project is jointly funded by Emerging Frontiers in the Directorate for Biological Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).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.