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.

该项目调查了美国西南部的四个不同生态系统如何应对温度和降水的变化。这很重要，因为温度和降水对生态系统具有很强的影响。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。但是，确切的变化速率和幅度尚不清楚。该项目将通过使用减少降水量和温暖土壤的实验治疗来研究关键知识差距。该实验已经持续了近二十年。该项目将支持未来五年的实验完成。主要问题是，随着时间的流逝，对温度和降水的转移的初始反应是否一致，或者生态系统是否适应新条件。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。外展活动将通过当地的非营利组织与广泛的受众进行。最后，将在线提供有关主要生产，植物社区组成以及生态系统碳和营养平衡的数据，以开放访问格式提供。该项目将扩展一个跨多种生态系统类型进行的独特长期实验，将时间表扩展到二十年以上。该实验发生在C. hart Merriam高程梯度上，从旧金山山峰的森林山坡延伸到科罗拉多高原的林地和沙漠，该地区以其对气候的高敏感性而确定。该项目遵循了一个较早的假设，即温度和降水的变化将引起在十年时间尺度上维持的半干旱生态系统中初级产量的进行性减少。换句话说，对干旱和热量的互动效应的响应可能会越来越下降。在这里，将测试两种可能推动这种变化的机制：植物群落的变化以及氮循环的变化。预测这两种效应的组合调节了长期碳和对实验变暖的养分平衡反应。由于这些渐进效应在社区变化和生物地球化学的时间尺度上（数十年）进行，因此测量它们需要继续此长期数据集。在这种情况下，二十年将是足够的时间来查看总生态系统碳和氮平衡的实验反应。这些反应可能会在沿着高度梯度代表的生物群落中有所不同，而渐进效应的幅度很大程度上可以解释。测试从沙漠草原到针叶林的生态系统中的这些渐进效应，将填补生态系统科学的关键知识差距。该奖项反映了NSF的法定任务，并认为值得通过基金会的知识分子优点和更广泛的影响来通过评估来支持。

项目成果

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.

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