Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements
Abstract Variations in tree water sources are important to understand in semi‐arid ecosystems because climatic shifts towards lower snowpack and increased drought affect water availability in subalpine forests of the western US. Here, we use daily in situ measurements of stable isotopes (2H & 18...
Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-08-01
|
| Series: | Water Resources Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024WR039171 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846173987403464704 |
|---|---|
| author | Matthias Sprenger Stefan Seeger Max Berkelhammer Nathaniel A. Bogie Raymond J. Hess Wendy S. Brown Sylvain Kuppel James Knighton |
| author_facet | Matthias Sprenger Stefan Seeger Max Berkelhammer Nathaniel A. Bogie Raymond J. Hess Wendy S. Brown Sylvain Kuppel James Knighton |
| author_sort | Matthias Sprenger |
| collection | DOAJ |
| description | Abstract Variations in tree water sources are important to understand in semi‐arid ecosystems because climatic shifts towards lower snowpack and increased drought affect water availability in subalpine forests of the western US. Here, we use daily in situ measurements of stable isotopes (2H & 18O) in soil and tree stem water, soil matric potential and sap flow to study tree water uptake dynamics. We instrumented three soil profiles down to 90 cm, as well as three aspen and engelmann spruce trees near Gothic, Colorado, in the East River watershed. We observed the fate of natural isotopic variations in rainfall, soil, and plants from June to October 2022, and in August 2023 we conducted a 2H labeled irrigation experiment. Our observations showed that all studied aspen trees compensated for water scarcity in the shallow soil by shifting the dominant water source at 60(±20) cm to ⅔ of uptake from 90 cm within a few days of a dry period. Both species relied on snowmelt stored in the subsoil to sustain transpiration. Intense rainfall caused the plant water uptake to shift partially to top soil layers within 2 days. Spruce transpiration was lower and relied more on snowmelt, because rainfall infiltration was low in the spruce stand due to high canopy interception. Our findings highlight the important role of snowmelt stored in the deep soil layers for subalpine forest drought response and the dominant fate of monsoonal rainfall to become transpiration rather than recharging groundwater and streams in the Upper Colorado River. |
| format | Article |
| id | doaj-art-27b5c407bb0f43d7a1b8be2ed82271d2 |
| institution | Kabale University |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Water Resources Research |
| spelling | doaj-art-27b5c407bb0f43d7a1b8be2ed82271d22025-08-26T12:02:54ZengWileyWater Resources Research0043-13971944-79732025-08-01618n/an/a10.1029/2024WR039171Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope MeasurementsMatthias Sprenger0Stefan Seeger1Max Berkelhammer2Nathaniel A. Bogie3Raymond J. Hess4Wendy S. Brown5Sylvain Kuppel6James Knighton7Lawrence Berkeley National Laboratory Berkeley CA USADepartment of Crop Sciences Chair of Soil Physics University of Göttingen Göttingen GermanyDepartment of Earth and Environmental Sciences University of Illinois Chicago Chicago IL USADepartment of Geology San José State University San Jose CA USADepartment of Earth and Environmental Sciences Rutgers University Newark NJ USAThe Rocky Mountain Biological Laboratory Crested Butte CO USAGéosciences Environment Toulouse CNRS ‐ IRD ‐ UT3 ‐ CNES Toulouse FranceDepartment of Natural Resources and the Environment University of Connecticut Storrs CT USAAbstract Variations in tree water sources are important to understand in semi‐arid ecosystems because climatic shifts towards lower snowpack and increased drought affect water availability in subalpine forests of the western US. Here, we use daily in situ measurements of stable isotopes (2H & 18O) in soil and tree stem water, soil matric potential and sap flow to study tree water uptake dynamics. We instrumented three soil profiles down to 90 cm, as well as three aspen and engelmann spruce trees near Gothic, Colorado, in the East River watershed. We observed the fate of natural isotopic variations in rainfall, soil, and plants from June to October 2022, and in August 2023 we conducted a 2H labeled irrigation experiment. Our observations showed that all studied aspen trees compensated for water scarcity in the shallow soil by shifting the dominant water source at 60(±20) cm to ⅔ of uptake from 90 cm within a few days of a dry period. Both species relied on snowmelt stored in the subsoil to sustain transpiration. Intense rainfall caused the plant water uptake to shift partially to top soil layers within 2 days. Spruce transpiration was lower and relied more on snowmelt, because rainfall infiltration was low in the spruce stand due to high canopy interception. Our findings highlight the important role of snowmelt stored in the deep soil layers for subalpine forest drought response and the dominant fate of monsoonal rainfall to become transpiration rather than recharging groundwater and streams in the Upper Colorado River.https://doi.org/10.1029/2024WR039171stable isotopesEcohydrologyisotope hydrologyplant water uptakevadose zonecritical zone |
| spellingShingle | Matthias Sprenger Stefan Seeger Max Berkelhammer Nathaniel A. Bogie Raymond J. Hess Wendy S. Brown Sylvain Kuppel James Knighton Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements Water Resources Research stable isotopes Ecohydrology isotope hydrology plant water uptake vadose zone critical zone |
| title | Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements |
| title_full | Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements |
| title_fullStr | Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements |
| title_full_unstemmed | Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements |
| title_short | Opportunistic Short‐Term Water Uptake Dynamics by Subalpine Trees Observed via In Situ Water Isotope Measurements |
| title_sort | opportunistic short term water uptake dynamics by subalpine trees observed via in situ water isotope measurements |
| topic | stable isotopes Ecohydrology isotope hydrology plant water uptake vadose zone critical zone |
| url | https://doi.org/10.1029/2024WR039171 |
| work_keys_str_mv | AT matthiassprenger opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT stefanseeger opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT maxberkelhammer opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT nathanielabogie opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT raymondjhess opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT wendysbrown opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT sylvainkuppel opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements AT jamesknighton opportunisticshorttermwateruptakedynamicsbysubalpinetreesobservedviainsituwaterisotopemeasurements |