Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Uncovering the critical soil moisture thresholds of plant water stress for European ecosystems

Fu, Zheng ; Ciais, Philippe ; Makowski, David ; Bastos, Ana ; Stoy, Paul C. ; Ibrom, Andreas ; Knohl, Alexander ; Migliavacca, Mirco ; Cuntz, Matthias and Šigut, Ladislav , et al. (2022) In Global Change Biology 28(6). p.2111-2123
Abstract

Understanding the critical soil moisture (SM) threshold (θcrit) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the θcrit across biomes and climates is challenging because observations of surface energy fluxes and SM remain sparse. Here, we used the latest database of eddy covariance measurements to estimate θcrit across Europe by evaluating evaporative fraction (EF)-SM relationships and investigating the covariance between vapor pressure deficit (VPD) and gross primary production (GPP) during SM dry-down periods. We found that the θcrit and soil matric... (More)

Understanding the critical soil moisture (SM) threshold (θcrit) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the θcrit across biomes and climates is challenging because observations of surface energy fluxes and SM remain sparse. Here, we used the latest database of eddy covariance measurements to estimate θcrit across Europe by evaluating evaporative fraction (EF)-SM relationships and investigating the covariance between vapor pressure deficit (VPD) and gross primary production (GPP) during SM dry-down periods. We found that the θcrit and soil matric potential threshold in Europe are 16.5% and −0.7 MPa, respectively. Surface energy partitioning characteristics varied among different vegetation types; EF in savannas had the highest sensitivities to SM in water-limited stage, and the lowest in forests. The sign of the covariance between daily VPD and GPP consistently changed from positive to negative during dry-down across all sites when EF shifted from relatively high to low values. This sign of the covariance changed after longer period of SM decline in forests than in grasslands and savannas. Estimated θcrit from the VPD–GPP covariance method match well with the EF–SM method, showing this covariance method can be used to detect the θcrit. We further found that soil texture dominates the spatial variability of θcrit while shortwave radiation and VPD are the major drivers in determining the spatial pattern of EF sensitivities. Our results highlight for the first time that the sign change of the covariance between daily VPD and GPP can be used as an indicator of how ecosystems transition from energy to SM limitation. We also characterized the corresponding θcrit and its drivers across diverse ecosystems in Europe, an essential variable to improve the representation of water stress in land surface models.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Global Change Biology
volume
28
issue
6
pages
2111 - 2123
publisher
Wiley-Blackwell
external identifiers
  • pmid:34927310
  • scopus:85122157145
ISSN
1354-1013
DOI
10.1111/gcb.16050
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2021 John Wiley & Sons Ltd.
id
f8b3d90c-0588-4186-903e-2a9c5fb4c148
date added to LUP
2022-01-30 12:54:52
date last changed
2024-04-20 20:53:08
@article{f8b3d90c-0588-4186-903e-2a9c5fb4c148,
  abstract     = {{<p>Understanding the critical soil moisture (SM) threshold (θ<sub>crit</sub>) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the θ<sub>crit</sub> across biomes and climates is challenging because observations of surface energy fluxes and SM remain sparse. Here, we used the latest database of eddy covariance measurements to estimate θ<sub>crit</sub> across Europe by evaluating evaporative fraction (EF)-SM relationships and investigating the covariance between vapor pressure deficit (VPD) and gross primary production (GPP) during SM dry-down periods. We found that the θ<sub>crit</sub> and soil matric potential threshold in Europe are 16.5% and −0.7 MPa, respectively. Surface energy partitioning characteristics varied among different vegetation types; EF in savannas had the highest sensitivities to SM in water-limited stage, and the lowest in forests. The sign of the covariance between daily VPD and GPP consistently changed from positive to negative during dry-down across all sites when EF shifted from relatively high to low values. This sign of the covariance changed after longer period of SM decline in forests than in grasslands and savannas. Estimated θ<sub>crit</sub> from the VPD–GPP covariance method match well with the EF–SM method, showing this covariance method can be used to detect the θ<sub>crit</sub>. We further found that soil texture dominates the spatial variability of θ<sub>crit</sub> while shortwave radiation and VPD are the major drivers in determining the spatial pattern of EF sensitivities. Our results highlight for the first time that the sign change of the covariance between daily VPD and GPP can be used as an indicator of how ecosystems transition from energy to SM limitation. We also characterized the corresponding θ<sub>crit</sub> and its drivers across diverse ecosystems in Europe, an essential variable to improve the representation of water stress in land surface models.</p>}},
  author       = {{Fu, Zheng and Ciais, Philippe and Makowski, David and Bastos, Ana and Stoy, Paul C. and Ibrom, Andreas and Knohl, Alexander and Migliavacca, Mirco and Cuntz, Matthias and Šigut, Ladislav and Peichl, Matthias and Loustau, Denis and El-Madany, Tarek S. and Buchmann, Nina and Gharun, Mana and Janssens, Ivan and Markwitz, Christian and Grünwald, Thomas and Rebmann, Corinna and Mölder, Meelis and Varlagin, Andrej and Mammarella, Ivan and Kolari, Pasi and Bernhofer, Christian and Heliasz, Michal and Vincke, Caroline and Pitacco, Andrea and Cremonese, Edoardo and Foltýnová, Lenka and Wigneron, Jean Pierre}},
  issn         = {{1354-1013}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{2111--2123}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Global Change Biology}},
  title        = {{Uncovering the critical soil moisture thresholds of plant water stress for European ecosystems}},
  url          = {{http://dx.doi.org/10.1111/gcb.16050}},
  doi          = {{10.1111/gcb.16050}},
  volume       = {{28}},
  year         = {{2022}},
}