Collaborative Research: Impacts of Dynamic, Climate-Driven Water Availability on Tree Water Use and Health in Mediterranean Riparian Forests

合作研究：气候驱动的动态水资源供应对地中海河岸森林树木用水和健康的影响

• 批准号: 1700555
• 负责人: Michael Singer
• 金额: $ 39.66万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1700555&HistoricalAwards=false
• 关键词: Collaborative; Research; Impacts; Dynamic; Climate

Forests along rivers are under threat due to climate-driven changes in water availability to trees. When water in the rooting zone is limited, trees undergo physiological changes that affect their overall growth and health. This problem is particularly acute within forests in river floodplains in regions with warm, dry summers (e.g., large areas of the USA). Such forests provide a range of ecosystem services, but they are limited in area, species diversity, and are challenging to manage under a changing climate. This project aims to build new understanding of the ?ecohydrological? links between water availability and forest health by employing an interdisciplinary set of research methods. It involves extracting tree cores from floodplain trees to investigate annual growth and will further investigate the ?isotopic signatures? of source water used by trees as recorded within each annual ring. By also monitoring climate variations and collecting water from various contributing sources, the project will provide insight into variations in potential source waters to forest trees. To generalize this research, the research will employ a numerical model to assess how climate controls water access to forests under plausible scenarios of regional climate change. The project will generate: new tools and information for practitioners of forest/water/basin management, international educational opportunities for underrepresented groups in the hydrologic sciences, and a new ecohydrology course for undergraduates. This research project combines: 1) field-based measurements of climate and hydrology and laboratory analysis of oxygen isotopes from all potential tree water sources; (2) contemporary and retrospective analysis of oxygen and carbon isotopes in annual tree-rings to investigate recent climate-driven fluctuations in tree water use and water use efficiency; (3) seasonal (intra-annual) analysis of oxygen isotopes via high-resolution ?micro-slicing? of annual tree rings to assess seasonal fluctuations in tree water source use; and 4) improvement and application of a climate-driven numerical ecohydrology model that includes dynamic water fluxes into the floodplain, isotopic fractionation/mixing, and tree water uptake. It will compare the ecohydrologic responses to climate in water availability at forest sites along a strong climatic gradient. There is currently limited ability to link tree/forest response to decadal climate shifts. Generalizable understanding linking regional climate to water availability to water use by riparian trees across forests stands is currently lacking, which limits predictive capability of forest response to drought stress over decadal timescales. This research will enable: i) identification of signatures of water stress within riparian forests; ii) predictive capability of forest response to climate change; iii) a clearer picture of regional variations in the expression of climate within floodplain water availability; and iv) improvement of dendro-paleoclimate reconstructions by providing better constraints on water availability and use under different conditions of climatic forcing. This research project will provide managers with a new perspective and tools for anticipating and mitigating the risks of climate change on vulnerable riparian forest resources along major rivers in temperate and Mediterranean climatic regions. The project will host a 2-day workshop to disseminate our findings to practitioners and stakeholders in in the study region. It also includes a Research Experiences for Undergraduates (REU) supplement to enable two female and/or minority students to travel to France as their first international trip to participate on the first field campaign. The REU will provide these students will an exciting international research experience, a world-class learning opportunity, and an introduction to a potential career in environmental/hydrologic sciences. Additionally, data and models from this research will be integrated into a new upper division course on dryland ecohydrology at UCSB.

由于气候驱动的树木可用性变化，河流沿岸的森林受到威胁。当生根区的水受到限制时，树木会经历影响其整体生长和健康的生理变化。这个问题在温暖，干燥的夏季（例如，美国大区域）的地区的河流洪泛区的森林中尤为严重。这样的森林提供了一系列的生态系统服务，但它们的面积，物种多样性有限，并且在不断变化的气候下管理挑战。该项目旨在建立对生态水文的新理解？通过采用一组跨学科研究方法，水的可用性与森林健康之间的联系。它涉及从洪泛区从洪泛区中提取树芯以调查年增长，并将进一步研究同位素的特征？每年戒指中记录的树木使用的源水。通过监测气候变化并从各种贡献来源收集水，该项目将洞悉潜在的林木源水的变化。为了概括这项研究，该研究将采用数值模型来评估气候如何在区域气候变化的合理情况下控制水进入森林。该项目将生成：针对森林/水域管理从业者的新工具和信息，水文科学中代表性不足的群体的国际教育机会，以及针对本科生的新生态水文课程。 该研究项目结合了：1）基于现场的气候和水文学的测量以及从所有潜在树水来源的氧同位素的实验室分析； （2）对年度环中的氧气和碳同位素的当代和回顾性分析，以调查最新气候驱动的树木用水和用水效率中的气候驱动的波动； （3）通过高分辨率？每年的树环以评估树水源使用中的季节性波动； 4）改进和应用气候驱动的数值生态水文模型，其中包括动态水通量进入洪泛区，同位素分级/混合和树水吸收。它将比较沿着强烈气候梯度的森林地点的气候的生态水文反应。目前，将树/森林响应与十年气候变化联系起来的能力有限。目前缺乏将区域气候与水的供应与河岸树的用水联系起来的可概括的理解，目前缺乏河岸树木的用水，这限制了森林对干旱压力的预测能力在十年时间尺度上。这项研究将实现：i）鉴定河岸森林中水压力的特征； ii）森林对气候变化的反应的预测能力； iii）更清楚地了解了洪泛区水的气候表达的区域变化； iv）通过在气候强迫的不同条件下提供更好的限制和使用，改善了dendro-paleoclimate的重建。该研究项目将为经理提供一种新的观点和工具，以预测和减轻气候变化对温带和地中海气候区域主要河流沿脆弱河岸森林资源的风险。该项目将举办为期2天的研讨会，将我们的发现传播给研究区的从业者和利益相关者。它还包括针对本科生（REU）补充的研究经验，使两名女学生和/或少数族裔学生能够前往法国，这是他们第一次参加首次参加比赛的国际旅行。 REU将为这些学生提供令人兴奋的国际研究经验，世界一流的学习机会，并介绍了环境/水文科学领域的潜在职业。此外，这项研究的数据和模型将集成到UCSB的Dryland Ecohydrology上新的上层分区课程中。

项目成果

Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow

河岸林地对地下水的依赖以及人为改变的水流的破坏作用

• DOI: 10.1073/pnas.2026453118
• 发表时间: 2021
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Rohde, Melissa M.;Stella, John C.;Roberts, Dar A.;Singer, Michael Bliss
• 通讯作者: Singer, Michael Bliss

DRYP 1.0: a parsimonious hydrological model of DRYland Partitioning of the water balance

DRYP 1.0：DRYland 水平衡的简约水文模型

• DOI: 10.5194/gmd-14-6893-2021
• 发表时间: 2021
• 期刊: Geoscientific Model Development
• 影响因子: 5.1
• 作者: Quichimbo, E. Andrés;Singer, Michael Bliss;Michaelides, Katerina;Hobley, Daniel E.;Rosolem, Rafael;Cuthbert, Mark O.
• 通讯作者: Cuthbert, Mark O.

Local and non-local controls on seasonal variations in water availability and use by riparian trees along a hydroclimatic gradient

地方和非地方对水资源供应的季节性变化以及沿水文气候梯度的河岸树木的利用进行控制

• DOI: 10.1088/1748-9326/ac1294
• 发表时间: 2021
• 期刊: Environmental Research Letters
• 影响因子: 6.7
• 作者: Sargeant, Christopher I;Singer, Michael Bliss
• 通讯作者: Singer, Michael Bliss