LTREB: Legacy effects of compounding disturbances in the Amazon: implications for ecosystem carbon and water cycling

LTREB：亚马逊复合干扰的遗留影响：对生态系统碳和水循环的影响

• 批准号: 2027827
• 负责人: Paulo Brando
• 金额: $ 59.96万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2023-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2027827&HistoricalAwards=false
• 关键词: LTREB; Legacy; effects; compounding; disturbances

The carbon stored in the Amazon’s forests is equivalent to ten years of current global carbon fossil-fuel emissions. This large carbon reservoir has seemingly grown over the past few decades and mitigated some of the negative effects on the global climate system associated with greenhouse gas emissions. At the same time, Amazon forests transfer enough moisture to the atmosphere to influence regional precipitation patterns. Interactions between climate change, deforestation, logging, windstorms, and wildfires have threatened the carbon stocks and climate regulatory functions of Amazon forests. Growing concerns that ongoing climate change combined with human disturbances will change Amazon forests into open savannas across large regions. This long term experiment in environmental biology award focuses on a forest that lies at the edge between continuous neotropical forests and savannas. This is an area where native vegetation has been fragmented and is frequently subject to interactions between human and natural disturbances such as fires, droughts, and windstorms. This award evaluates forest resilience from seasonally dry evergreen tropical forests to multiple disturbances based on long- term ecological measurements of a highly threatened Amazon forest. The project’s outcomes could inform regional land and fire management, particularly the development of new strategies to avoid catastrophic wildfires that reduce the capacity of forests to provide ecosystem services. This award will also connect US-based research with researchers and institutions in Brazil, in the process helping to train a diverse group of US students. Finally, the award represents important benchmarks for land surface models and remote sensing techniques that have been widely used to understand potential trajectories of tropical forests This award tests the hypothesis that forests subjected to novel compounding disturbances use different pathways to recover climate services. Disturbed forests that experience minor, short-term reductions in climate functions such as ET and net carbon uptake, have high forest resilience and low probability of large-scale forest replacement by scrubland. However, repeated disturbances triggering long-term losses of forest climate functions would point to low forest resilience. This award will add a decade of ecological data to a long-term, large-scale experimental site in southeast Amazonia that has been degraded by edge effects, recurrent fires, two windthrow events, and multiple droughts. These extended data measurements will permit a comprehensive assessment of how potential future pathways of the experimentally disturbed forests affect ecosystem-level climatic functions across different successional forest pathways and as plant traits change. The experimental site is located in one of the most threatened regions of the Amazon, on the boundary between a dense evergreen rainforest and seasonally dry forests and where native vegetation has been fragmented and subjected to anthropogenic (fire, edge effects) and natural disturbances (droughts and windthrow events). How forests’ long-term climate functions change as a function of novel disturbances and climate change has direct implications for the future of the world’s largest tropical forest. This award will rely on long-term ecological measurements to build a clearer understanding of Amazon forest resilience to multiple disturbances. It will evaluate how interactions between fire legacies to trees (e.g., wounds to tree trunks) and extreme weather events (droughts, windstorms) affect forest climatic functions. In the next ten years, this award will lead to a new understanding of how forest successional pathways and plant traits influence ecosystem-level ET and carbon stocks following compounding disturbances. This award will provide new insights into the (as yet unquantified) thresholds that may lead to large-scale ecosystem change under future climate and land use changes.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.

亚马逊森林中存储的碳等于目前的全球碳化石燃料排放量十年。在过去的几十年中，这位大型碳浮雕似乎已经增长，并减轻了对与温室气体排放相关的全球气候系统的一些负面影响。同时，亚马逊森林将足够的水分转移到大气中，以影响区域降水模式。气候变化，森林砍伐，伐木，风暴和野火之间的相互作用威胁到亚马逊森林的碳库存和气候调节功能。越来越担心的是，持续的气候变化与人类灾难相结合将使亚马逊森林变成大型地区的开放式稀树草原。这个环境生物学奖的长期实验集中在森林中，该森林位于连续的新热带森林和稀树草原之间的边缘。这是一个本地植被已经分散的区域，经常受到人类和自然灾害（例如火灾，干旱和暴风雨）之间的相互作用。该奖项根据对高度威胁的亚马逊森林的长期生态测量，评估了从季节性干燥的常绿热带森林到多种灾难的森林韧性。该项目的结果可以为区域土地和消防管理提供依据，尤其是制定新策略，以避免灾难性的野火，从而降低了森林提供生态系统服务的能力。在此过程中，该奖项还将与巴西的研究人员和机构联系起来，这有助于培训我们的潜水员团体。最后，该奖项代表着广泛用于了解热带森林潜在轨迹的陆地表面模型和遥感技术的重要基准。该奖项检验了一个假设，即受到新型复合疾病的森林使用不同的途径来恢复气候服务。令人不安的森林经历了较小的，短期减少的气候功能，例如ET和净碳吸收，具有较高的森林弹性，并且scrubland替代大规模森林的可能性很低。但是，反复造成的灾难引发了森林攀岩功能的长期损失将表明森林的韧性低。该奖项将在亚马逊东南部的长期大规模实验场所中增加十年的生态数据，并因边缘效应，经常性火灾，两次风吹动事件和多次干旱而降级。这些扩展的数据测量结果将允许全面评估实验影响的生态系统级的潜在未来途径如何在不同的成功森林途径上以及随着植物特征的变化而进行的。实验地点位于亚马逊地区最受威胁的地区之一，在密集的常绿雨林和季节性干燥的森林之间的边界上，当地植被已被碎裂并遭受人为（火，边缘效应）和自然灾害（干旱和风能事件）。森林的长期气候功能如何随着新颖的灾难和气候变化而变化，对世界上最大的热带森林的未来有直接的影响。该奖项将依靠长期的生态测量来对亚马逊森林的韧性进行更清晰的了解，以实现多种令人惊讶的结果。它将评估火灾遗产与树木（例如树干的伤口）与极端天气事件（干旱，暴风雨）之间的相互作用如何影响森林气候功能。在接下来的十年中，该奖项将使人们对森林途径和植物特征如何影响复合灾难后的生态系统级别的ET和碳种群有了新的了解。该奖项将提供有关（尚未量化的）阈值的新见解，这些阈值可能在未来的气候和土地利用变化下导致大规模的生态系统变化。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的审查标准通过评估来评估的。