RAPID: Does riparian vegetation state mediate consequences of climate change-induced extreme flooding for stream-riparian food webs and communities?

RAPID：河岸植被状况是否会调节气候变化引起的极端洪水对河岸食物网和社区的影响？

• 批准号: 2244011
• 负责人: Colden Baxter
• 金额: $ 9.99万
• 依托单位: Idaho State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2244011&HistoricalAwards=false
• 关键词: RAPID; Does; riparian; vegetation; state

In June 2022, Northern Yellowstone National Park experienced rain-on-snow events leading to a 1 in 500-year flood, devastating local infrastructure and capturing public attention as a high-profile consequence of human-caused climate change. Extreme disturbances, whether they be category 5 hurricanes, severe wildfires, or extreme droughts, are becoming more frequent and intense. Natural resource managers and policy makers need to understand the consequences of such extreme disturbances and find ways to support ecosystem resiliency. Historically, ecologists thought that though ecosystems were resilient to, or even benefitted from, mild or moderate disturbances, extreme disturbances “reset” ecosystems to some uniform, baseline state. NSF has approved RAPID support for this project, to evaluate extreme disturbance in the context of Northern Yellowstone. The study area contains considerable biodiversity throughout a mosaic of distinct habitats. One source of this complexity comes from the restoration of predators like wolves and grizzly bears, their interactions with herbivores such as elk and bison, and the subsequent changes to plant communities. As a result, willows and alders have regrown around some streams and rivers while others, just miles away, remain dominated by grasses and sedges. Previous investigations showed that different plant communities influence the diversity and productivity of streams and rivers, but in ways mediated by local context that result in a mosaic of ecosystem states. Just as the restoration of predators has not uniformly changed this ecosystem, responses to the recent extreme flooding may have been mediated by local context. In turn, results from this study may inform management decisions and influence public perceptions regarding consequences of such disturbances, as indeed past ecological studies have done for wildfire in this region.Through the opportunistic use of a natural experiment and by comparing stream-riparian ecosystems before and after the extreme flooding, this project will evaluate whether a homogenous “reset” of stream-riparian ecosystems occurred, or if terrestrial wildlife dynamics that influence riparian vegetation state, as well as pre-flood traits of aquatic communities, mediated heterogeneous responses of stream-riparian organisms and ecosystem processes. This project will collect parallel measurements after flooding to those collected before, including stream-riparian habitat characteristics, herbivory and riparian plant community composition and structure, stream ecosystem organic matter dynamics, productivity and food web interactions of aquatic invertebrates and fish, and riparian spider and bird communities. If organism, community, or food web traits shape resistance, resilience, and trajectories of change following the extreme flood, this will provide an opportunity to evaluate how such “ecological memory” constrains responses to future extreme events. If traits of organisms and communities are indeed important to mediating responses to extreme disturbances, this project may highlight the importance of conserving such complexity in the face of climate change and the biodiversity crisis.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.

2022年6月，北黄石国家公园经历了降雨和降雪事件，导致500年一遇的洪水，破坏了当地的基础设施，并作为人类引起的气候变化的高调后果引起了公众的关注。极端干扰，无论是5级飓风、严重野火还是极端干旱，正变得越来越频繁和强烈。自然资源管理者和政策制定者需要了解这种极端干扰的后果，并找到支持生态系统恢复能力的方法。从历史上看，生态学家认为，尽管生态系统对轻度或中度干扰具有弹性，甚至从中受益，但极端干扰将生态系统“重置”到某种统一的基线状态。NSF已经批准了RAPID对该项目的支持，以评估黄石公园北部的极端干扰。研究区域包含相当多的生物多样性，遍布不同的栖息地。这种复杂性的一个来源是狼和灰熊等食肉动物的恢复，它们与麋鹿和野牛等食草动物的相互作用，以及随后植物群落的变化。结果，柳树和桤木在一些溪流和河流周围重新生长，而在几英里外的其他地方，仍然被草和莎草所主宰。先前的研究表明，不同的植物群落影响溪流和河流的多样性和生产力，但其方式受当地环境的调节，导致生态系统状态的马赛克。正如捕食者的恢复并没有完全改变这个生态系统一样，对最近极端洪水的反应可能是由当地环境调节的。反过来，这项研究的结果可能会为管理决策提供信息，并影响公众对此类干扰后果的看法，正如过去对该地区野火的生态研究所做的那样。通过机会性地利用自然实验，并通过比较极端洪水前后的河流-河岸生态系统，该项目将评估河流-河岸生态系统是否发生了同质性的“重置”，或者影响河岸植被状态的陆地野生动物动态，以及水生群落的洪水前特征，是否介导了河流-河岸生物和生态系统过程的异质反应。该项目将收集洪水后与洪水前的平行测量数据，包括河流-河岸栖息地特征、食草和河岸植物群落组成和结构、河流生态系统有机质动态、水生无脊椎动物和鱼类的生产力和食物网相互作用、河岸蜘蛛和鸟类群落。如果生物、群落或食物网的特征塑造了极端洪水后的抵抗力、恢复力和变化轨迹，这将提供一个机会来评估这种“生态记忆”如何限制对未来极端事件的反应。如果生物和群落的特征确实对调节对极端干扰的反应很重要，那么这个项目可能会突出在面对气候变化和生物多样性危机时保护这种复杂性的重要性。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。