Collaborative Research: The other side of tropical forest drought: Do shallow water table regions of Amazonia act as large-scale hydrological refugia from drought?

合作研究：热带森林干旱的另一面：亚马逊流域的浅水位区域是否可以作为干旱的大型水文避难所？

• 批准号: 1949894
• 负责人: Scott Saleska
• 金额: $ 28.86万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1949894&HistoricalAwards=false
• 关键词: Collaborative; Research; other; side; tropical

The vegetation that covers the Earth has many important functions. One of the biggest impacts of vegetation is trapping and storing carbon dioxide from the atmosphere. The vast Amazon rainforest makes a significant contribution to this carbon storage function. However, the Amazon forest is being threatened by recent changes to climate, which is making droughts stronger and more frequent. A big question is whether the Amazon will be resilient to these droughts, or whether they will slow forest growth and kill trees, which would release carbon. A significant challenge is the lack of information about a large portion of the Amazon forest—about 30%—with shallow water tables, where trees live in an environment of excess water. In these water-logged forests, tree growth is slow because soil conditions are poor for tree roots. Here, drought could actually be beneficial to trees by reducing this water-logging. On the other hand, these forests have roots that grow close to the soil surface and require wet conditions. In this case, strong droughts that last a long time dry the upper soil and could reduce growth more, killing more trees than in forests with well-drained soils. This project will answer questions about the role of belowground water sources as an important control on response of tropical forest to drought. Data about forest growth and carbon dioxide exchange will be made available to the broader research community. This project will also help train students in how to measure forests, and provide information about tropical forests to the public.This project will measure forest canopy response to drought at sites in the Brazilian Amazon. The approach is to unify field ecology with remote observation of ecosystems from canopy towers and satellites. Canopy towers constructed in this project—representing the first of their kind in water-logged soils of the interior Amazon—provide detailed information about tree growth. The capacity of the forest canopy for photosynthesis will be measured as well as leaf demography and phenology. This new knowledge will be combined with networks of existing canopy towers in deep water table depth sites, satellite images spanning the Amazon, data on tree growth and death from a network of forest surveys, and detailed measurements of soil water and other environmental factors. This project will build an accurate new understanding of the factors that impact forest carbon cycling, while contrasting water-logged with well-drained soil responses. A data-based model of ecosystem structure and function will offer a quantitative accounting of the contribution of these water-logged forests in the Amazon to climate change responses. These results have the potential to transform our current perspective on drought effects in tropical forests.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.

覆盖地球的植被具有许多重要的功能，其中之一是捕获和储存大气中的二氧化碳，巨大的亚马逊雨林对这种碳储存功能做出了重大贡献。最近的气候变化使干旱变得更加严重和更加频繁，一个大问题是亚马逊是否能够抵御这些干旱，或者它们是否会减缓森林生长并杀死树木，从而释放碳。缺乏有关亚马逊大部分地区的信息森林——约30%——地下水位较浅，树木生活在水分过多的环境中。在这些积水的森林中，树木生长缓慢，因为土壤条件对树根来说很差。在这里，干旱实际上对树木有利。另一方面，这些森林的根系靠近土壤表面生长，需要潮湿的条件。在这种情况下，持续很长时间的强烈干旱会导致上层土壤干燥，从而进一步减少生长，从而导致死亡。树木比土壤排水良好的森林更多。该项目将回答有关地下水源作为热带森林应对干旱的重要控制作用的问题，并将向更广泛的研究界提供有关森林生长和二氧化碳交换的数据。该项目还将帮助培训学生。如何测量森林，并向公众提供有关热带森林的信息。该项目将测量巴西亚马逊地区森林冠层对干旱的反应，该方法是将现场生态学与冠层塔和卫星对生态系统的远程观测结合起来。在此建造的塔楼该项目是亚马逊内陆浸水土壤中的第一个此类项目，将测量森林冠层的光合作用能力以及树叶人口统计和物候学的详细信息。该项目将利用深水位深度地点的现有树冠塔网络、横跨亚马逊的卫星图像、森林调查网络中的树木生长和死亡数据以及土壤水和其他环境因素的详细测量数据，建立一个准确的新系统。的理解影响森林碳循环的因素，同时对比浸水和排水良好的土壤响应，基于数据的生态系统结构和功能模型将定量计算亚马逊地区这些浸水森林对气候变化响应的贡献。这些结果有可能改变我们目前对热带森林干旱影响的看法。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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

Reframing tropical savannization: linking changes in canopy structure to energy balance alterations that impact climate

重塑热带稀树草原化：将冠层结构的变化与影响气候的能量平衡变化联系起来

• DOI: 10.1002/ecs2.3231
• 发表时间: 2020-09
• 期刊: Ecosphere
• 影响因子: 2.7
• 作者: Stark, Scott C.;Breshears, David D.;Aragón, Susan;Villegas, Juan Camilo;Law, Darin J.;Smith, Marielle N.;Minor, David M.;de Assis, Rafael Leandro;de Almeida, Danilo Roberti Alves;de Oliveira, Gabriel;et al
• 通讯作者: et al

Asymmetric response of Amazon forest water and energy fluxes to wet and dry hydrological extremes reveals onset of a local drought‐induced tipping point

亚马逊森林水和能量通量对潮湿和干燥水文极端情况的不对称响应揭示了当地干旱引发的临界点的开始

• DOI: 10.1111/gcb.16933
• 发表时间: 2023-09-12
• 期刊: Global Change Biology
• 影响因子: 11.6
• 作者: N. Restrepo;Bradley O'Donnell Christoffersen;Marcos Longo;Luciana F. Alves;K. S. Campos;Aless;ro C da Araujo;ro;R. D. de Oliveira;N. Prohaska;R. da Silva;Raphael Tapajós;K. Wiedemann;S. Wofsy;S. Saleska
• 通讯作者: S. Saleska

Diverse anthropogenic disturbances shift Amazon forests along a structural spectrum

各种人为干扰使亚马逊森林发生结构变化

• DOI: 10.1002/fee.2590
• 发表时间: 2023-02
• 期刊: Frontiers in Ecology and the Environment
• 影响因子: 10.3
• 作者: Smith, Marielle N;Stark, Scott C;Taylor, Tyeen C;Schietti, Juliana;de Almeida, Danilo Roberti;Aragón, Susan;Torralvo, Kelly;Lima, Albertina P;de Oliveira, Gabriel;de Assis, Rafael Leandro;et al
• 通讯作者: et al