LTREB renewal: Progressive Responses to Environmental Change Across Multiple Ecosystems

LTREB 更新：跨多个生态系统对环境变化的渐进响应

• 批准号: 1754204
• 负责人: Bruce Hungate
• 金额: $ 45万
• 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: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1754204&HistoricalAwards=false
• 关键词: LTREB; renewal; Progressive; Responses; Environmental

This project investigates how four different ecosystems in the southwestern U.S. respond to changes in temperature and precipitation. This is important because temperature and precipitation have strong effects on ecosystems. The main effects are on the flow of carbon, the supply of nutrients, the types of soil microbes, and the growth of plants. However, the exact rate and magnitude of change are unknown. This project will investigate a key knowledge gap by using experimental treatments that reduce precipitation and warm soil. This experiment has been sustained for almost two decades. This project will support the completion of the experiment in the next five years. The main question is whether the initial responses to shifts in temperature and precipitation are consistent over time, or whether the ecosystems adjust to the new conditions. In addition, this project will support scientific workforce training. Undergraduate and graduate students will be trained in methods of data collection and analysis. Outreach activities will be conducted with broad audiences through local non-profit groups. Finally, data will be provided online about primary production, plant community composition, and ecosystem carbon and nutrient balance, in open access format.This project will extend a unique long-term experiment conducted across multiple ecosystem types, extending the timeline to over two decades. This experiment occurs along the C. Hart Merriam elevation gradient, extending from the forested slopes of the San Francisco Peaks to the woodlands and deserts of the Colorado Plateau, a region identified for its high sensitivity to climate. The project follows up on an earlier hypothesis that change in temperature and precipitation will elicit progressive reductions in primary production in semi-arid ecosystems that are sustained on decadal timescales. In other words, primary production may increasingly decline in response to the interactive effects of drought and heat. Here, two mechanisms will be tested that could drive this change: shifts in the plant community and changes in the nitrogen cycle. The prediction is that the combination of these two effects modulates long-term carbon and nutrient balance responses to experimental warming. Because these progressive effects operate on the timescales of community change and biogeochemistry (years to decades), measuring them requires continuing this long-term dataset. In this case, two decades will be sufficient time to see experimental responses of total ecosystem carbon and nitrogen balance. It is likely that that these responses will vary among the biomes represented along the elevational gradient, with the variation largely explained by the magnitude of the progressive effects. Testing these progressive effects across ecosystems ranging from desert grasslands to coniferous forests will fill critical knowledge gaps in ecosystem science.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.

该项目研究了美国西南部四种不同的生态系统如何应对温度和降水的变化。这一点很重要，因为温度和降水对生态系统有很大的影响。主要影响是碳的流动，养分的供应，土壤微生物的类型和植物的生长。然而，确切的变化率和幅度尚不清楚。该项目将通过使用减少降水和温暖土壤的实验性处理方法来调查一个关键的知识缺口。这项实验已经持续了近二十年。该项目将支持在今后五年内完成这项试验。主要的问题是，对温度和降水变化的最初反应是否随着时间的推移而保持一致，或者生态系统是否会适应新的条件。此外，该项目将支持科学劳动力培训。本科生和研究生将接受数据收集和分析方法的培训。将通过当地非营利团体向广大受众开展外联活动。最后，将以开放获取的形式在线提供有关初级生产、植物群落组成以及生态系统碳和养分平衡的数据。该项目将扩展在多种生态系统类型中进行的独特的长期实验，将时间轴延长到20多年。这个实验沿着C.哈特梅里亚姆海拔梯度，从圣弗朗西斯科峰的森林覆盖的山坡延伸到科罗拉多高原的林地和沙漠，该地区对气候高度敏感。该项目是根据早先的一个假设进行的，即温度和降水量的变化将导致在十年时间尺度上持续的半干旱生态系统的初级生产逐步减少。换句话说，由于干旱和炎热的相互影响，初级生产可能会日益下降。在这里，将测试两种机制，可以驱动这种变化：植物群落的变化和氮循环的变化。预测是，这两种效应的结合调节了对实验变暖的长期碳和营养平衡反应。由于这些渐进的影响作用于群落变化和生物地球化学的时间尺度（几年到几十年），测量它们需要继续这个长期的数据集。在这种情况下，20年将是足够的时间来观察总生态系统碳和氮平衡的实验响应。很可能，这些响应将在代表沿着海拔梯度的生物群落之间变化，这种变化主要由渐进效应的大小来解释。从沙漠草原到针叶林，测试这些跨越生态系统的渐进效应将填补生态系统科学的关键知识空白。该奖项反映了NSF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。

项目成果

Developing climate-smart restoration: Can plant microbiomes be hardened against heat waves?

• DOI: 10.1002/eap.1763
• 发表时间: 2018-07
• 期刊: Ecological applications : a publication of the Ecological Society of America
• 作者: Rachel L. Rubin;G. Koch;Ayla Martinez;Rebecca L. Mau;M. Bowker;B. Hungate

Plant growth promoting rhizobacteria are more effective under drought: a meta-analysis

促进植物生长的根际细菌在干旱下更有效：荟萃分析

• DOI: 10.1007/s11104-017-3199-8
• 发表时间: 2017
• 期刊: Plant and Soil
• 影响因子: 4.9
• 作者: Rubin, Rachel L.;van Groenigen, Kees Jan;Hungate, Bruce A.
• 通讯作者: Hungate, Bruce A.