Award Abstract # 1700555
Collaborative Research: Impacts of Dynamic, Climate-Driven Water Availability on Tree Water Use and Health in Mediterranean Riparian Forests

NSF Org: EAR
Division Of Earth Sciences
Recipient: UNIVERSITY OF CALIFORNIA, SANTA BARBARA
Initial Amendment Date: July 11, 2017
Latest Amendment Date: July 11, 2017
Award Number: 1700555
Award Instrument: Standard Grant
Program Manager: Hendratta Ali
heali@nsf.gov
 (703)292-2648
EAR
 Division Of Earth Sciences
GEO
 Directorate for Geosciences
Start Date: August 1, 2017
End Date: July 31, 2022 (Estimated)
Total Intended Award Amount: $396,566.00
Total Awarded Amount to Date: $396,566.00
Funds Obligated to Date: FY 2017 = $396,566.00
History of Investigator:
  • Michael Singer (Principal Investigator)
    bliss@eri.ucsb.edu
  • Kelly Caylor (Co-Principal Investigator)
Recipient Sponsored Research Office: University of California-Santa Barbara
3227 CHEADLE HALL
SANTA BARBARA
CA  US  93106-0001
(805)893-4188
Sponsor Congressional District: 24
Primary Place of Performance: University of California-Santa Barbara
 UK
Primary Place of Performance
Congressional District:
Unique Entity Identifier (UEI): G9QBQDH39DF4
Parent UEI:
NSF Program(s): Hydrologic Sciences
Primary Program Source: 01001718DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):
Program Element Code(s): 157900
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

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.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Evans, Cristina M. and Dritschel, David G. and Singer, Michael B. "Modeling Subsurface Hydrology in Floodplains" Water Resources Research , v.54 , 2018 https://doi.org/10.1002/2017WR020827 Citation Details
Janssen, Philippe and Stella, John C. and Piégay, Hervé and Räpple, Bianca and Pont, Bernard and Faton, Jean-Michel and Cornelissen, Johannes Hans and Evette, André "Divergence of riparian forest composition and functional traits from natural succession along a degraded river with multiple stressor legacies" Science of The Total Environment , v.721 , 2020 https://doi.org/10.1016/j.scitotenv.2020.137730 Citation Details
Quichimbo, E. Andrés and Singer, Michael Bliss and Michaelides, Katerina and Hobley, Daniel E. and Rosolem, Rafael and Cuthbert, Mark O. "DRYP 1.0: a parsimonious hydrological model of DRYland Partitioning of the water balance" Geoscientific Model Development , v.14 , 2021 https://doi.org/10.5194/gmd-14-6893-2021 Citation Details
Quichimbo, Edisson A. and Singer, Michael B. and Cuthbert, Mark O. "Characterising groundwatersurface water interactions in idealised ephemeral stream systems" Hydrological Processes , 2020 https://doi.org/10.1002/hyp.13847 Citation Details
Rohde, Melissa M. and Stella, John C. and Roberts, Dar A. and Singer, Michael Bliss "Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow" Proceedings of the National Academy of Sciences , v.118 , 2021 https://doi.org/10.1073/pnas.2026453118 Citation Details
Sargeant, Christopher I and Singer, Michael Bliss "Local and non-local controls on seasonal variations in water availability and use by riparian trees along a hydroclimatic gradient" Environmental Research Letters , v.16 , 2021 https://doi.org/10.1088/1748-9326/ac1294 Citation Details
Sargeant, Christopher I. and Singer, Michael Bliss and ValletCoulomb, Christine "Identification of SourceWater Oxygen Isotopes in Trees Toolkit (ISOTool) for Deciphering Historical Water Use by Forest Trees" Water Resources Research , v.55 , 2019 https://doi.org/10.1029/2018WR024519 Citation Details
Singer, Michael Bliss and Michaelides, Katerina "Deciphering the expression of climate change within the Lower Colorado River basin by stochastic simulation of convective rainfall" Environmental Research Letters , v.12 , 2017 10.1088/1748-9326/aa8e50 Citation Details
Singer, Michael Bliss and Michaelides, Katerina and Hobley, Daniel E. "STORM 1.0: a simple, flexible, and parsimonious stochastic rainfall generator for simulating climate and climate change" Geoscientific Model Development , v.11 , 2018 10.5194/gmd-11-3713-2018 Citation Details
Warter, Maria Magdalena and Singer, Michael Bliss and Cuthbert, Mark O. and Roberts, Dar and Caylor, Kelly K. and Sabathier, Romy and Stella, John "Drought onset and propagation into soil moisture and grassland vegetation responses during the 20122019 major drought in Southern California" Hydrology and Earth System Sciences , v.25 , 2021 https://doi.org/10.5194/hess-25-3713-2021 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

This project was designed to investigate how climate controls the amount of water that is available to forest trees in forest patches along a major river floodplain, the Rhone River in France. We used tree coring, analysis of water sources and climate records and information from satellites about the greenness of vegetation to examine how floodplain forests respond to drought conditions that affect how much water is in the root zone. 

We found:

1) Different tree types that co-exist in these floodplain forests have access to different water sources (either from the shallow soil or from deeper groundwater) depending on how deeply they are rooted.

2) These different species therefore respond to different climatic conditions. Specifically, moisture in the shallow soil is controlled locally by how much rain falls and how much is lost back to the atmosphere through evaporation. In contrast, groundwater is controlled by snow accumulation far away in the Alps that gradually moves down to the lowlands. This means that deeply rooted trees are less affected by local drought conditions In other words, some climate conditions (lack of local rainfall) could be harmful to one species, while other condtiions (below-normal snowpack) may be harmful to the other species of tree.

3) The peak greenness for forest trees along the Rhone River is not sensitive to temperature, as it is for other species, but to the availability of water during the period of growth. 

These research outcomes could be of broad relevance to other academic fields (ecology, hydrology, physical geography), as well as to forest and water managers trying to anticipate how climate change will impact their forest resources.      


Last Modified: 12/08/2022
Modified by: Michael Singer

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