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，可能会频繁和/或同时发生。在接下来的几十年里，这些极端事件可能会发生得更频繁，对自然和人类景观的影响可能会比极端事件单独发生时更严重。2015年和2016年，南部非洲的许多地区遭受了复合极端的影响，当时干旱和大量使用野生动物导致国家公园的植被覆盖率和大规模野生动物死亡率大幅下降。许多地区尚未完全恢复。复合极端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、食物生产和碳储存。虽然越来越多的证据表明，生态系统内生物多样性(即生物多样性)可能是关键，但极端事件后恢复的机制尚不清楚。该奖项将在南非稀树大草原试验性地实施复合极端，并将测量结果纳入计算机模型，以了解植物生命的多样性如何控制复合极端之后的生态系统恢复。该项目提供的信息和工具对于土地管理者和政策制定者通过促进生物多样性最大限度地发挥公有和私有土地的恢复潜力具有重要意义。此外，该项目将为不同的人群(南非当地利益相关者、高中、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，并将优先发展多样性、公平和纳入科学。目前，生物多样性对生态系统恢复(即复原力)的重要性在社区一级得到承认，但物种多样性的基础机制尚未得到很好的理解，这些机制可以将这些概念扩展到其他空间和等级尺度。生物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其环境的反应；这有助于使用基本原理从生物到种群、群落和生态系统。这项研究将首先通过使用方法来检查植物特征的多样性(例如，功能分散)，从而将生物多样性弹性概念扩展到简单的物种多样性。其次，它将扩大生物多样性-复原力的关系，从单个有机体，到种群和社区，再到整个生态系统。为此，该项目将在南非稀树大草原上单独和联合实施极端干旱、极端放牧和极端火灾的试验，并确定(1)处理前、处理中和处理后的功能特征的多样性，以与(2)处理中和处理后的个人、种群、社区和生态系统的反应相联系。然后，将使用经验数据对机械性人口植被模型进行参数设置和基准测试，以将这些影响的推论扩展到更长的时间范围和更广泛的生物多样性情景。这个项目将解决的三个主要问题是：(1)不同等级尺度的多样性如何控制扰动后生物功能的弹性？(2)扰动如何影响多个等级尺度的生物多样性？(3)多样性和韧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新兴前沿和已建立的刺激竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.