Quantifying Plant Mediation of Ecosystem Multifunction in Response to Fire and Warming

量化植物对生态系统多功能响应火灾和变暖的调节作用

• 批准号: 2139676
• 负责人: Rachel Mitchell
• 金额: $ 25万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2139676&HistoricalAwards=false
• 关键词: Quantifying; Plant; Mediation; Ecosystem; Multifunction

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Wildfire and warm temperatures affect how ecosystems function, but their impacts can also be mediated by plant communities. For example, wildfire and warming may speed up decomposition rates in the soil, but this trend can be slowed if the plant community produces leaves that are thicker and tougher to decompose. Ecosystems are shaped by disturbances like fire, and when these disturbances change, some species may be unable to survive. This project examines how fire severity and experimental warming interact to shape plant traits, plant communities, and multiple ecosystem functions such as decomposition and plant productivity. The project studies ponderosa pine forest understory communities in Arizona. This work is of critical importance as the climate warms and increasingly severe fires occur over large area of the western United States. Results from the study provide valuable information about biodiversity, ecosystem function, and ecosystem stability in the future. In addition, the project trains a new generation of scientists in ecosystem science.The project implements an experimental manipulation of temperature that mimics future climate scenarios across a fire severity gradient that encompasses a range of fire severities. The project addresses three key hypotheses: 1) Fire severity, climate alteration, and their interactions will strengthen abiotic filtering relative to untreated controls; 2) Fire severity, climate alterations, and their interactions will reduce plant trait diversity relative to untreated controls; and 3) The relative importance of indirect, plant mediated effects of fire severity and climate alterations will increase over time, ultimately leading to a reduction in ecosystem function in burned and warmed plots. Changes in the plant community and ecosystem function are quantified, and then used to calculate two metrics of ecosystem function. Finally, structural equation modelling is used to answer our overarching research question: How does the understory plant community mediate the effects of fire severity and climate change on ecosystem multifunction over time?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.

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。野火和温暖的温度影响生态系统的功能，但它们的影响也可以通过植物群落来调节。例如，野火和变暖可能会加快土壤的分解速度，但如果植物群落产生更厚、更难分解的叶子，这种趋势就会减缓。生态系统是由火灾等干扰形成的，当这些干扰发生变化时，一些物种可能无法生存。该项目研究火灾的严重程度和实验变暖如何相互作用，以塑造植物性状，植物群落和多种生态系统功能，如分解和植物生产力。该项目研究亚利桑那州的黄松林林下群落。这项工作是至关重要的，因为气候变暖，越来越严重的火灾发生在美国西部的大面积。研究结果为未来的生物多样性、生态系统功能和生态系统稳定性提供了有价值的信息。此外，该项目还培训新一代生态系统科学科学家，对温度进行实验性操纵，模拟未来火灾严重程度梯度的气候情景，包括一系列火灾严重程度。 该项目解决了三个关键假设：1）火灾严重度，气候变化，以及它们的相互作用将加强非生物过滤相对于未经处理的控制; 2）火灾严重度，气候变化，以及它们的相互作用将减少植物性状多样性相对于未经处理的控制;和3）间接的，植物介导的火灾严重性和气候变化的影响的相对重要性将随着时间的推移而增加，最终导致燃烧和升温地块的生态系统功能下降。植物群落和生态系统功能的变化被量化，然后用于计算生态系统功能的两个指标。最后，结构方程模型是用来回答我们的首要研究问题：林下植物群落如何调解火灾的严重程度和气候变化对生态系统多功能随着时间的推移的影响？该奖项反映了NSF的法定使命，并被认为是值得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的支持。