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Shekhar A, Hörtnagl L, Paul-Limoges E, Etzold S, Zweifel R, Buchmann N, Gharun M. Contrasting impact of extreme soil and atmospheric dryness on the functioning of trees and forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:169931. [PMID: 38199368 DOI: 10.1016/j.scitotenv.2024.169931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Abstract
Recent studies indicate an increase in the frequency of extreme compound dryness days (days with both extreme soil AND air dryness) across central Europe in the future, with little information on their impact on the functioning of trees and forests. This study aims to quantify and assess the impact of extreme soil dryness, extreme air dryness, and extreme compound dryness on the functioning of trees and forests. For this, >15 years of ecosystem-level (carbon dioxide and water vapor fluxes) and 6-10 years of tree-level measurements (transpiration and growth) each from a montane mixed deciduous forest (CH-Lae) and a subalpine evergreen coniferous forest (CH-Dav) in Switzerland, is used. The results showed extreme air dryness limitation on CO2 fluxes and extreme soil dryness limitations on water vapor fluxes. Additionally, CH-Dav was mainly affected by extreme air dryness whereas CH-Lae was affected by both extreme soil dryness and extreme air dryness. The impact of extreme compound dryness on net CO2 uptake (about 75 % decrease) was more due to higher increased ecosystem respiration (40 % and 70 % increase at CH-Dav and CH-Lae, respectively) than decreased gross primary productivity (10 % and 40 % decrease at CH-Dav and CH-Lae, respectively). A significant negative impact on evapotranspiration and transpiration was only observed at CH-Lae during extreme soil and compound dryness (about 25 % decrease). Furthermore, with some differences, the tree-level impact on tree water deficit, transpiration, and growth were consistent with the ecosystem-level impact on carbon uptake and evapotranspiration. Finally, the impact of extreme dryness showed no significant relationship with tree allometry (diameter and height) but across different tree species. The projected future is likely to expose these forest areas to more extreme and frequent dryness conditions, thus compromising the functioning of trees and forests, thereby calling for management interventions to increase the adaptive capacity and resistance of these forests.
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Affiliation(s)
- Ankit Shekhar
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland.
| | - Lukas Hörtnagl
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Eugénie Paul-Limoges
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Sophia Etzold
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Roman Zweifel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Mana Gharun
- Faculty of Geosciences, University of Münster, 48149 Münster, Germany
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2
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Tang ACI, Flechard CR, Arriga N, Papale D, Stoy PC, Buchmann N, Cuntz M, Douros J, Fares S, Knohl A, Šigut L, Simioni G, Timmermans R, Grünwald T, Ibrom A, Loubet B, Mammarella I, Belelli Marchesini L, Nilsson M, Peichl M, Rebmann C, Schmidt M, Bernhofer C, Berveiller D, Cremonese E, El-Madany TS, Gharun M, Gianelle D, Hörtnagl L, Roland M, Varlagin A, Fu Z, Heinesch B, Janssens I, Kowalska N, Dušek J, Gerosa G, Mölder M, Tuittila ES, Loustau D. Detection and attribution of an anomaly in terrestrial photosynthesis in Europe during the COVID-19 lockdown. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166149. [PMID: 37567315 DOI: 10.1016/j.scitotenv.2023.166149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 08/04/2023] [Accepted: 08/06/2023] [Indexed: 08/13/2023]
Abstract
Carbon dioxide (CO2) uptake by plant photosynthesis, referred to as gross primary production (GPP) at the ecosystem level, is sensitive to environmental factors, including pollutant exposure, pollutant uptake, and changes in the scattering of solar shortwave irradiance (SWin) - the energy source for photosynthesis. The 2020 spring lockdown due to COVID-19 resulted in improved air quality and atmospheric transparency, providing a unique opportunity to assess the impact of air pollutants on terrestrial ecosystem functioning. However, detecting these effects can be challenging as GPP is influenced by other meteorological drivers and management practices. Based on data collected from 44 European ecosystem-scale CO2 flux monitoring stations, we observed significant changes in spring GPP at 34 sites during 2020 compared to 2015-2019. Among these, 14 sites showed an increase in GPP associated with higher SWin, 10 sites had lower GPP linked to atmospheric and soil dryness, and seven sites were subjected to management practices. The remaining three sites exhibited varying dynamics, with one experiencing colder and rainier weather resulting in lower GPP, and two showing higher GPP associated with earlier spring melts. Analysis using the regional atmospheric chemical transport model (LOTOS-EUROS) indicated that the ozone (O3) concentration remained relatively unchanged at the research sites, making it unlikely that O3 exposure was the dominant factor driving the primary production anomaly. In contrast, SWin increased by 9.4 % at 36 sites, suggesting enhanced GPP possibly due to reduced aerosol optical depth and cloudiness. Our findings indicate that air pollution and cloudiness may weaken the terrestrial carbon sink by up to 16 %. Accurate and continuous ground-based observations are crucial for detecting and attributing subtle changes in terrestrial ecosystem functioning in response to environmental and anthropogenic drivers.
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Affiliation(s)
- Angela Che Ing Tang
- ISPA, Bordeaux Sciences Agro, INRAE, Villenave d'Ornon, France; Department of Environmental Sciences, University of Toledo, Toledo, OH, USA.
| | | | - Nicola Arriga
- Joint Research Centre, European Commission, Ispra, Italy
| | - Dario Papale
- University of Tuscia DIBAF, Viterbo, Italy; EuroMediterranean Center on Climate Change, CMCC IAFES, Viterbo, Italy
| | - Paul C Stoy
- Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Matthias Cuntz
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, Nancy, France
| | - John Douros
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands
| | - Silvano Fares
- National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean, Naples, Italy
| | | | - Ladislav Šigut
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Brno, Czech Republic
| | | | - Renske Timmermans
- Climate Air and Sustainability Unit, Netherlands Organisation for Applied Scientific Research (TNO), Utrecht, The Netherlands
| | - Thomas Grünwald
- Faculty of Environmental Sciences, Institute of Hydrology and Meteorology, Technische Universität Dresden, Tharandt, Germany
| | - Andreas Ibrom
- Technical University of Denmark (DTU), DTU-Sustain, Kgs. Lyngby, Denmark
| | - Benjamin Loubet
- UMR ECOSYS, AgroParisTech, INRAE, Université Paris-Saclay, Thiverval-Grignon, France
| | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | | | - Mats Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Corinna Rebmann
- Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Marius Schmidt
- Institute of Bio- and Geosciences: Agrosphere (IBG-3), Jülich Research Centre, Jülich, Germany
| | - Christian Bernhofer
- Faculty of Environmental Sciences, Institute of Hydrology and Meteorology, Technische Universität Dresden, Tharandt, Germany
| | - Daniel Berveiller
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique et Evolution, Orsay, France
| | - Edoardo Cremonese
- Environmental Protection Agency of Aosta Valley - Climate Change Unit, Saint-Christophe, Italy
| | - Tarek S El-Madany
- Max Planck Institute for Biogeochemistry, Department of Biogeochemical Integration, Jena, Germany
| | - Mana Gharun
- Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland; Faculty of Geosciences, University of Münster, Münster, Germany
| | - Damiano Gianelle
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Lukas Hörtnagl
- Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Marilyn Roland
- Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Andrej Varlagin
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
| | - Zheng Fu
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Bernard Heinesch
- TERRA Teaching and Research Centre, University of Liege, Gembloux, Belgium
| | - Ivan Janssens
- Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Natalia Kowalska
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Dušek
- Department of Matter and Energy Fluxes, Global Change Research Institute of the Czech Academy of Sciences, Brno, Czech Republic
| | | | - Meelis Mölder
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | | | - Denis Loustau
- ISPA, Bordeaux Sciences Agro, INRAE, Villenave d'Ornon, France
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3
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Miller DL, Wolf S, Fisher JB, Zaitchik BF, Xiao J, Keenan TF. Increased photosynthesis during spring drought in energy-limited ecosystems. Nat Commun 2023; 14:7828. [PMID: 38030605 PMCID: PMC10687245 DOI: 10.1038/s41467-023-43430-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 11/09/2023] [Indexed: 12/01/2023] Open
Abstract
Drought is often thought to reduce ecosystem photosynthesis. However, theory suggests there is potential for increased photosynthesis during meteorological drought, especially in energy-limited ecosystems. Here, we examine the response of photosynthesis (gross primary productivity, GPP) to meteorological drought across the water-energy limitation spectrum. We find a consistent increase in eddy covariance GPP during spring drought in energy-limited ecosystems (83% of the energy-limited sites). Half of spring GPP sensitivity to precipitation was predicted solely from the wetness index (R2 = 0.47, p < 0.001), with weaker relationships in summer and fall. Our results suggest GPP increases during spring drought for 55% of vegetated Northern Hemisphere lands ( >30° N). We then compare these results to terrestrial biosphere model outputs and remote sensing products. In contrast to trends detected in eddy covariance data, model mean GPP always declined under spring precipitation deficits after controlling for air temperature and light availability. While remote sensing products captured the observed negative spring GPP sensitivity in energy-limited ecosystems, terrestrial biosphere models proved insufficiently sensitive to spring precipitation deficits.
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Affiliation(s)
- David L Miller
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA.
| | - Sebastian Wolf
- Department of Environmental Systems Science, ETH Zurich, 8092, Zurich, Switzerland.
| | - Joshua B Fisher
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
| | - Benjamin F Zaitchik
- Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, 03824, USA
| | - Trevor F Keenan
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA.
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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4
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Li H, Zhang F, Li J, Guo X, Zhou H, Li Y. Differential responses of CO 2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai-Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165863. [PMID: 37516184 DOI: 10.1016/j.scitotenv.2023.165863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Discrete extreme heat events, deluges, and droughts will become more frequent and disproportionately affect the processes and functions of grassland ecosystems. Here, we compared the responses of CO2 and heat fluxes to natural extreme events in 2016 in a lower alpine meadow and neighboring upper shrubland on the northeastern Qinghai-Tibetan Plateau. Unlike insensitive sensible heat flux, latent heat flux (LE) increased by 21.8 % in the meadow and by 56.4 % in the shrubland during a dry period and subsequent compound hot-dry period in August. Changes (Δ, data for 2016 minus the corresponding means from other years) in the heat flux at both sites were determined by changes in solar radiation (ΔSwin), as sufficient soil moisture was available. ΔLE was more sensitive to ΔSwin in the open-canopy shrubland, reflecting its greater capacity for evaporative cooling to buffer climate anomalies. CO2 fluxes responded weakly to extreme wet or dry events but strongly when those events were accompanied by exceptional heat. During single or compound hot events, the mean changes in total ecosystem respiration (ΔTER) increased by about 30 % in both grasslands, although ΔTER was more sensitive to changes in the topsoil temperature in the more productive meadow than in the shrubland. The mean changes in gross primary productivity (ΔGPP) fluctuated by <10 % in the warmer meadow but increased by 29.3 % in the cooler shrubland relative to the respective baseline, probably because of the differences in canopy structure and root depth and the consequent high-temperature stress on vegetation photosynthesis. The changes in net ecosystem CO2 exchange (ΔNEE) were significantly related to ΔTER in the meadow and increased by 55.8 %, whereas ΔNEE was controlled mainly by ΔGPP in the shrubland and decreased by 22.4 %. Overall, both alpine grasslands were resistant to rainfall anomalies but susceptible to exceptional warmth, with the differential responses being ascribed to canopy structure and root depth. Our results provide helpful insights based on which the carbon sequestration and water-holding functions of alpine grasslands during future climate change can be predicted.
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Affiliation(s)
- Hongqin Li
- College of Life Sciences, Luoyang Normal University, Luoyang, Henan 471934, China; Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China
| | - Fawei Zhang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China.
| | - Jiexia Li
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China
| | - Xiaowei Guo
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China
| | - Huakun Zhou
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China
| | - Yingnian Li
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China; Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Region, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810008, China
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5
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Shekhar A, Hörtnagl L, Buchmann N, Gharun M. Long-term changes in forest response to extreme atmospheric dryness. GLOBAL CHANGE BIOLOGY 2023; 29:5379-5396. [PMID: 37381105 DOI: 10.1111/gcb.16846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/01/2023] [Indexed: 06/30/2023]
Abstract
Atmospheric dryness, as indicated by vapor pressure deficit (VPD), has a strong influence on forest greenhouse gas exchange with the atmosphere. In this study, we used long-term (10-30 years) net ecosystem productivity (NEP) measurements from 60 forest sites across the world (1003 site-years) to quantify long-term changes in forest NEP resistance and NEP recovery in response to extreme atmospheric dryness. We tested two hypotheses: first, across sites differences in NEP resistance and NEP recovery of forests will depend on both the biophysical characteristics (i.e., leaf area index [LAI] and forest type) of the forest as well as on the local meteorological conditions of the site (i.e., mean VPD of the site), and second, forests experiencing an increasing trend in frequency and intensity of extreme dryness will show an increasing trend in NEP resistance and NEP recovery over time due to emergence of long-term ecological stress memory. We used a data-driven statistical learning approach to quantify NEP resistance and NEP recovery over multiple years. Our results showed that forest types, LAI, and median local VPD conditions explained over 50% of variance in both NEP resistance and NEP recovery, with drier sites showing higher NEP resistance and NEP recovery compared to sites with less atmospheric dryness. The impact of extreme atmospheric dryness events on NEP lasted for up to 3 days following most severe extreme events in most forests, indicated by an NEP recovery of less than 100%. We rejected our second hypothesis as we found no consistent relationship between trends of extreme VPD with trends in NEP resistance and NEP recovery across different forest sites, thus an increase in atmospheric dryness as it is predicted might not increase the resistance or recovery of forests in terms of NEP.
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Affiliation(s)
- Ankit Shekhar
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Lukas Hörtnagl
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Mana Gharun
- Institute of Landscape Ecology, Faculty of Geosciences, University of Münster, Münster, Germany
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6
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Peters RL, Steppe K, Pappas C, Zweifel R, Babst F, Dietrich L, von Arx G, Poyatos R, Fonti M, Fonti P, Grossiord C, Gharun M, Buchmann N, Steger DN, Kahmen A. Daytime stomatal regulation in mature temperate trees prioritizes stem rehydration at night. THE NEW PHYTOLOGIST 2023. [PMID: 37235688 DOI: 10.1111/nph.18964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/16/2023] [Indexed: 05/28/2023]
Abstract
Trees remain sufficiently hydrated during drought by closing stomata and reducing canopy conductance (Gc ) in response to variations in atmospheric water demand and soil water availability. Thresholds that control the reduction of Gc are proposed to optimize hydraulic safety against carbon assimilation efficiency. However, the link between Gc and the ability of stem tissues to rehydrate at night remains unclear. We investigated whether species-specific Gc responses aim to prevent branch embolisms, or enable night-time stem rehydration, which is critical for turgor-dependent growth. For this, we used a unique combination of concurrent dendrometer, sap flow and leaf water potential measurements and collected branch-vulnerability curves of six common European tree species. Species-specific Gc reduction was weakly related to the water potentials at which 50% of branch xylem conductivity is lost (P50 ). Instead, we found a stronger relationship with stem rehydration. Species with a stronger Gc control were less effective at refilling stem-water storage as the soil dries, which appeared related to their xylem architecture. Our findings highlight the importance of stem rehydration for water-use regulation in mature trees, which likely relates to the maintenance of adequate stem turgor. We thus conclude that stem rehydration must complement the widely accepted safety-efficiency stomatal control paradigm.
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Affiliation(s)
- Richard L Peters
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Forest is Life, TERRA Teaching and Research Centre, Gembloux Agro Bio-Tech, University of Liège, Passage des Déportés 2, 5030, Gembloux, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
| | - Christoforos Pappas
- Department of Civil Engineering, University of Patras, Rio, Patras, 26504, Greece
| | - Roman Zweifel
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Flurin Babst
- School of Natural Resources and the Environment, University of Arizona, East Lowell Street 1064, Tucson, AZ, 85721, USA
- Laboratory of Tree-Ring Research, University of Arizona, East Lowell Street 1215, Tucson, AZ, 857121, USA
| | - Lars Dietrich
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Georg von Arx
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Rafael Poyatos
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Marina Fonti
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Patrick Fonti
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School for Architecture, Civil and Environmental Engineering, EPFL, CH-1015, Lausanna, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, CH-1015, Lausanne, Switzerland
| | - Mana Gharun
- Department of Environmental Systems Science, ETH Zurich, Universitatstrasse 2, CH-8092, Zurich, Switzerland
- Department of Geosciences, University of Münster, Heisenbergstrasse 2, 48149, Münster, Germany
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zurich, Universitatstrasse 2, CH-8092, Zurich, Switzerland
| | - David N Steger
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
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7
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Pohl F, Rakovec O, Rebmann C, Hildebrandt A, Boeing F, Hermanns F, Attinger S, Samaniego L, Kumar R. Long-term daily hydrometeorological drought indices, soil moisture, and evapotranspiration for ICOS sites. Sci Data 2023; 10:281. [PMID: 37179354 PMCID: PMC10183025 DOI: 10.1038/s41597-023-02192-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Eddy covariance sites are ideally suited for the study of extreme events on ecosystems as they allow the exchange of trace gases and energy fluxes between ecosystems and the lower atmosphere to be directly measured on a continuous basis. However, standardized definitions of hydroclimatic extremes are needed to render studies of extreme events comparable across sites. This requires longer datasets than are available from on-site measurements in order to capture the full range of climatic variability. We present a dataset of drought indices based on precipitation (Standardized Precipitation Index, SPI), atmospheric water balance (Standardized Precipitation Evapotranspiration Index, SPEI), and soil moisture (Standardized Soil Moisture Index, SSMI) for 101 ecosystem sites from the Integrated Carbon Observation System (ICOS) with daily temporal resolution from 1950 to 2021. Additionally, we provide simulated soil moisture and evapotranspiration for each site from the Mesoscale Hydrological Model (mHM). These could be utilised for gap-filling or long-term research, among other applications. We validate our data set with measurements from ICOS and discuss potential research avenues.
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Affiliation(s)
- Felix Pohl
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany.
| | - Oldrich Rakovec
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
- Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Kamýcká 129, Praha-Suchdol, 165 00, Czech Republic
| | - Corinna Rebmann
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Anke Hildebrandt
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
- Friedrich Schiller University Jena, Institute of Geoscience, Burgweg 11, 07749, Jena, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, 04103, Leipzig, Germany
| | - Friedrich Boeing
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Floris Hermanns
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Sabine Attinger
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
- University of Potsdam, Institute of Environmental Science and Geography, Am Neuen Palais 10, 14469, Potsdam, Germany
| | - Luis Samaniego
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
- University of Potsdam, Institute of Environmental Science and Geography, Am Neuen Palais 10, 14469, Potsdam, Germany
| | - Rohini Kumar
- Helmholtz-Centre for Environmental Research, Permoserstraße 15, 04318, Leipzig, Germany
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Li Y, Eugster W, Riedl A, Lehmann MM, Aemisegger F, Buchmann N. Dew benefits on alpine grasslands are cancelled out by combined heatwave and drought stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1136037. [PMID: 37229137 PMCID: PMC10203623 DOI: 10.3389/fpls.2023.1136037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/04/2023] [Indexed: 05/27/2023]
Abstract
Increasing frequencies of heatwaves combined with simultaneous drought stress in Europe threaten the ecosystem water and carbon budgets of alpine grasslands. Dew as an additional water source can promote ecosystem carbon assimilation. It is known that grassland ecosystems keep high evapotranspiration as long as soil water is available. However, it is rarely being investigated whether dew can mitigate the impact of such extreme climatic events on grassland ecosystem carbon and water exchange. Here we use stable isotopes in meteoric waters and leaf sugars, eddy covariance fluxes for H2O vapor and CO2, in combination with meteorological and plant physiological measurements, to investigate the combined effect of dew and heat-drought stress on plant water status and net ecosystem production (NEP) in an alpine grassland (2000 m elevation) during the June 2019 European heatwave. Before the heatwave, enhanced NEP in the early morning hours can be attributed to leaf wetting by dew. However, dew benefits on NEP were cancelled out by the heatwave, due to the minor contribution of dew in leaf water. Heat-induced reduction in NEP was intensified by the combined effect of drought stress. The recovery of NEP after the peak of the heatwave could be linked to the refilling of plant tissues during nighttime. Among-genera differences of plant water status affected by dew and heat-drought stress can be attributed to differences in their foliar dew water uptake, and their reliance on soil moisture or the impact of the atmospheric evaporative demand. Our results indicate that dew influence on alpine grassland ecosystems varies according to the environmental stress and plant physiology.
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Affiliation(s)
- Yafei Li
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Werner Eugster
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Andreas Riedl
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Marco M. Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | | | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
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9
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Niu Y, Schuchardt MA, von Heßberg A, Jentsch A. Stable plant community biomass production despite species richness collapse under simulated extreme climate in the European Alps. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 864:161166. [PMID: 36572286 DOI: 10.1016/j.scitotenv.2022.161166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/20/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Direct observation of biodiversity loss in response to abrupt climate change can resolve fundamental questions about temporal community dynamics and clarify the controversial debate of biodiversity loss impacts on ecosystem functioning. We tracked local plant species loss and the corresponding change of aboveground biomass of native and non-native species by actively pushing mountain grassland ecosystems beyond their ecological thresholds in a five-year, multisite translocation experiment across the European Alps. Our results show that species loss (ranging from a 73 % to 94 % reduction in species richness) caused by simulated climate extremes (strong warming interacting with drought) did not decrease community biomass. Even without non-native species colonization, the community biomass of native species remained stable during native species richness collapse. Switching our research focus from local extinction in the face of climate change towards the beneficial impacts of persisting native species (in addition to novel plant-plant interactions) might yield insights on transformative opportunities for boosting climate resilience.
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Affiliation(s)
- Yujie Niu
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth 95440, Germany.
| | - Max A Schuchardt
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth 95440, Germany.
| | - Andreas von Heßberg
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth 95440, Germany.
| | - Anke Jentsch
- Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth 95440, Germany.
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10
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Bose AK, Rohner B, Bottero A, Ferretti M, Forrester DI. Did the 2018 megadrought change the partitioning of growth between tree sizes and species? A Swiss case-study. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1146-1156. [PMID: 34939277 PMCID: PMC10078792 DOI: 10.1111/plb.13380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
By killing or weakening trees, drought could change the partitioning of growth between tree sizes or species, thereby altering stand structure. Growth partitioning, often quantified using the growth dominance coefficient (DC) or the shape of tree size versus growth relationships (SGR), indicates the relative contribution of differently sized trees to the total stand growth. Changes in growth partitioning due to droughts are rarely examined but provide valuable information that links tree- and stand-level responses to droughts. The objective of this study was to test whether the 2018 European megadrought altered the growth partitioning among tree sizes and species. For this purpose, we first evaluated whether DC or SGR can be calculated from small sample sizes of trees typical of individual forest inventory plots. DC, and particularly SGR, were sensitive to sample size, forest type (even-aged and uneven-aged), target variable (tree diameter, basal area or stem mass) and range of tree sizes within the sample. SGR could therefore not be used for our analyses. We found no differences in DC prior to and during the 2018 drought. However, when considering only beech (Fagus sylvatica)-dominated stands, DC was lower during post-drought years than during the 2018 drought. The growth of larger trees, especially beech, was more negatively affected during post-drought years. Therefore, an extreme drought event can indeed alter the growth partitioning within forest stands. The DC indicates such changes in partitioning and, hence, which trees can be selected for commercial thinning, or released from competition, to minimize potential impacts of droughts.
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Affiliation(s)
- A. K. Bose
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- Forestry and Wood Technology DisciplineKhulna UniversityKhulnaBangladesh
| | - B. Rohner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - A. Bottero
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- WSL Institute for Snow and Avalanche Research SLFDavos DorfSwitzerland
- Climate Change, Extremes and Natural Hazards in Alpine Regions Research Center (CERC)Davos DorfSwitzerland
| | - M. Ferretti
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - D. I. Forrester
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
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11
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Meusburger K, Trotsiuk V, Schmidt‐Walter P, Baltensweiler A, Brun P, Bernhard F, Gharun M, Habel R, Hagedorn F, Köchli R, Psomas A, Puhlmann H, Thimonier A, Waldner P, Zimmermann S, Walthert L. Soil-plant interactions modulated water availability of Swiss forests during the 2015 and 2018 droughts. GLOBAL CHANGE BIOLOGY 2022; 28:5928-5944. [PMID: 35795901 PMCID: PMC9546155 DOI: 10.1111/gcb.16332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/02/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Central Europe has been experiencing unprecedented droughts during the last decades, stressing the decrease in tree water availability. However, the assessment of physiological drought stress is challenging, and feedback between soil and vegetation is often omitted because of scarce belowground data. Here we aimed to model Swiss forests' water availability during the 2015 and 2018 droughts by implementing the mechanistic soil-vegetation-atmosphere-transport (SVAT) model LWF-Brook90 taking advantage of regionalized depth-resolved soil information. We calibrated the model against soil matric potential data measured from 2014 to 2018 at 44 sites along a Swiss climatic and edaphic drought gradient. Swiss forest soils' storage capacity of plant-available water ranged from 53 mm to 341 mm, with a median of 137 ± 42 mm down to the mean potential rooting depth of 1.2 m. Topsoil was the primary water source. However, trees switched to deeper soil water sources during drought. This effect was less pronounced for coniferous trees with a shallower rooting system than for deciduous trees, which resulted in a higher reduction of actual transpiration (transpiration deficit) in coniferous trees. Across Switzerland, forest trees reduced the transpiration by 23% (compared to potential transpiration) in 2015 and 2018, maintaining annual actual transpiration comparable to other years. Together with lower evaporative fluxes, the Swiss forests did not amplify the blue water deficit. The 2018 drought, characterized by a higher and more persistent transpiration deficit than in 2015, triggered widespread early wilting across Swiss forests that was better predicted by the SVAT-derived mean soil matric potential in the rooting zone than by climatic predictors. Such feedback-driven quantification of ecosystem water fluxes in the soil-plant-atmosphere continuum will be crucial to predicting physiological drought stress under future climate extremes.
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Affiliation(s)
- Katrin Meusburger
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Volodymyr Trotsiuk
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Paul Schmidt‐Walter
- Agrometeorological Research CenterGerman Weather Service (DWD)BraunschweigGermany
| | - Andri Baltensweiler
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Philipp Brun
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Fabian Bernhard
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Mana Gharun
- Department of Environmental Systems ScienceETH ZürichZürichSwitzerland
- Department of GeosciencesUniversity of MünsterMünsterGermany
| | - Raphael Habel
- Department of Soil and EnvironmentForest Research Institute Baden WürttembergFreiburgGermany
| | - Frank Hagedorn
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Roger Köchli
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Achilleas Psomas
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Heike Puhlmann
- Department of Soil and EnvironmentForest Research Institute Baden WürttembergFreiburgGermany
| | - Anne Thimonier
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Peter Waldner
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Stephan Zimmermann
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Lorenz Walthert
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)BirmensdorfSwitzerland
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12
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Response of Spruce Forest Ecosystem CO2 Fluxes to Inter-Annual Climate Anomalies in the Southern Taiga. FORESTS 2022. [DOI: 10.3390/f13071019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Climate extremes and anomalies modify the CO2 ecosystem–atmosphere exchange of the boreal forests and consequently alter the terrestrial carbon stocks and the atmospheric greenhouse gas concentrations. The effects of the anomalous weather conditions on the CO2 net ecosystem exchange (NEE), total ecosystem respiration (TER), and gross primary production (GPP) of the typical southern taiga nemorose spruce forest were analyzed using continuous eddy covariance flux measurements in the 2015–2020 period. The forest was found to be a source of atmospheric CO2 in 2016, 2017, 2019, and 2020 (the mean annual GPP/TER ratio was between 0.87 and 0.97). In 2018, the forest was found to act as a CO2 sink (GPP/TER = 1.47) when a positive temperature anomaly in the growing season was accompanied by a negative precipitation anomaly and increased global radiation. The early start of the CO2 uptake in the anomalously warm winter of 2019/2020 did not result in an increase in the annual GPP/TER ratio (0.90). The comparison of the flux data obtained from the nemorose spruce forest on the well-drained soils with the data obtained from paludified spruce forest in the same landscape showed that the mean annual GPP/TER ratio of the sites alternatively responded to the mentioned anomalies. This study suggests that a variety of soil moisture regimes across the southern taiga spruce forests provide a non-uniformity in the response reactions of the CO2 ecosystem–atmosphere exchange on the climate anomalies.
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13
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Arend M, Link RM, Zahnd C, Hoch G, Schuldt B, Kahmen A. Lack of hydraulic recovery as a cause of post-drought foliage reduction and canopy decline in European beech. THE NEW PHYTOLOGIST 2022; 234:1195-1205. [PMID: 35238410 PMCID: PMC9310744 DOI: 10.1111/nph.18065] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/19/2022] [Indexed: 05/06/2023]
Abstract
European beech (Fagus sylvatica) was among the most affected tree species during the severe 2018 European drought. It not only suffered from instant physiological stress but also showed severe symptoms of defoliation and canopy decline in the following year. To explore the underlying mechanisms, we used the Swiss-Canopy-Crane II site and studied in branches of healthy and symptomatic trees the repair of hydraulic function and concentration of carbohydrates during the 2018 drought and in 2019. We found loss of hydraulic conductance in 2018, which did not recover in 2019 in trees that developed defoliation symptoms in the year after drought. Reduced branch foliation in symptomatic trees was associated with a gradual decline in wood starch concentration throughout summer 2019. Visualization of water transport in healthy and symptomatic branches in the year after the drought confirmed the close relationship between xylem functionality and supported branch leaf area. Our findings showed that embolized xylem does not regain function in the season following a drought and that sustained branch hydraulic dysfunction is counterbalanced by the reduction in supported leaf area. It suggests acclimation of leaf development after drought to mitigate disturbances in canopy hydraulic function.
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Affiliation(s)
- Matthias Arend
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Roman Mathias Link
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Cedric Zahnd
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Günter Hoch
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Bernhard Schuldt
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Ansgar Kahmen
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
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14
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Sturm J, Santos MJ, Schmid B, Damm A. Satellite data reveal differential responses of Swiss forests to unprecedented 2018 drought. GLOBAL CHANGE BIOLOGY 2022; 28:2956-2978. [PMID: 35182091 PMCID: PMC9310759 DOI: 10.1111/gcb.16136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 05/31/2023]
Abstract
Extreme events such as the summer drought of 2018 in Central Europe are projected to occur more frequently in the future and may cause major damages including increased tree mortality and negative impacts on forest ecosystem services. Here, we quantify the response of >1 million forest pixels of 10 × 10 m across Switzerland to the 2018 drought in terms of resistance, recovery, and resilience. We used the Normalized Difference Water Index (NDWI) derived from Sentinel-2 satellite data as a proxy for canopy water content and analyzed its relative change. We calculated NDWI change between the 2017 pre-drought and 2018 drought years (indicating resistance), 2018 and the 2019 post-drought (indicating recovery), and between 2017-2019 (indicating resilience). Analyzing the data from this large natural experiment, we found that for 4.3% of the Swiss forest the NDWI declined between 2017 and 2018, indicating areas with low resistance of the forest canopy to drought effects. While roughly 50% of this area recovered, in 2.7% of the forested area NDWI continued to decline from 2018 to 2019, suggesting prolonged negative effects or delayed damage. We found differential forest responses to drought associated with site topographic characteristics and forest stand characteristics, and to a lesser extent with climatic conditions and interactions between these drivers. Low drought resistance and high recovery were most prominent at forest edges, but also on south-facing slopes and lower elevations. Tree functional type was the most important driver of drought resilience, with most of the damage in stands with high conifer abundance. Our results demonstrate the suitability of satellite-based quantification of drought-induced forest damage at high spatial resolution across large areas. Such information is important to predict how local site characteristics may impact forest vulnerability to future extreme events and help in the search for appropriate adaptation strategies.
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Affiliation(s)
- Joan Sturm
- Department of GeographyUniversity of ZurichZürichSwitzerland
| | - Maria J. Santos
- Department of GeographyUniversity of ZurichZürichSwitzerland
| | - Bernhard Schmid
- Department of GeographyUniversity of ZurichZürichSwitzerland
| | - Alexander Damm
- Department of GeographyUniversity of ZurichZürichSwitzerland
- Eawag, Swiss Federal Institute of Aquatic Science and TechnologyDübendorfSwitzerland
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15
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Sun Q, Gilgen AK, Signarbieux C, Klaus VH, Buchmann N. Cropping systems alter hydraulic traits of barley but not pea grown in mixture. PLANT, CELL & ENVIRONMENT 2021; 44:2912-2924. [PMID: 33763869 DOI: 10.1111/pce.14054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Extreme events such as drought and heatwaves are among the biggest challenges to agricultural production and food security. However, the effects of cropping systems on drought resistance of arable crops via their hydraulic behaviour remain unclear. We investigated how hydraulic traits of a field-grown pea-barley (Pisum sativum L. and Hordeum vulgare L.) mixture were affected by different cropping systems, that is, organic and conventional farming with intensive or conservation tillage. Xylem vulnerability to cavitation of both species was estimated by measuring the pressure inducing 50% loss of hydraulic conductivity (P50 ), while the water stress plants experienced in the field were assessed using native percentage loss of hydraulic conductivity (nPLC). Pea and barley showed contrasting hydraulic behaviours: pea was less vulnerable to xylem cavitation and less stressed than barley; cropping systems affected the xylem vulnerability of barley, but not of pea. Barley grown under conventional farming with no tillage was more vulnerable and stressed than under organic farming with intensive tillage. nPLC proved to be a valuable indicator for plant water stress. Our results highlight the impact of cropping systems on crop xylem vulnerability and drought resistance, thus plant hydraulic traits, for protecting food security under future climate.
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Affiliation(s)
- Qing Sun
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Anna K Gilgen
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Constant Signarbieux
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Ecological Systems Laboratory (ECOS), Lausanne, Switzerland
| | - Valentin H Klaus
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
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16
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Zweifel R, Sterck F, Braun S, Buchmann N, Eugster W, Gessler A, Häni M, Peters RL, Walthert L, Wilhelm M, Ziemińska K, Etzold S. Why trees grow at night. THE NEW PHYTOLOGIST 2021; 231:2174-2185. [PMID: 34118158 PMCID: PMC8457160 DOI: 10.1111/nph.17552] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 06/07/2021] [Indexed: 05/22/2023]
Abstract
The timing of diel stem growth of mature forest trees is still largely unknown, as empirical data with high temporal resolution have not been available so far. Consequently, the effects of day-night conditions on tree growth remained uncertain. Here we present the first comprehensive field study of hourly-resolved radial stem growth of seven temperate tree species, based on 57 million underlying data points over a period of up to 8 yr. We show that trees grow mainly at night, with a peak after midnight, when the vapour pressure deficit (VPD) is among the lowest. A high VPD strictly limits radial stem growth and allows little growth during daylight hours, except in the early morning. Surprisingly, trees also grow in moderately dry soil when the VPD is low. Species-specific differences in diel growth dynamics show that species able to grow earlier during the night are associated with the highest number of hours with growth per year and the largest annual growth increment. We conclude that species with the ability to overcome daily water deficits faster have greater growth potential. Furthermore, we conclude that growth is more sensitive than carbon uptake to dry air, as growth stops before stomata are known to close.
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Affiliation(s)
- Roman Zweifel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
| | - Frank Sterck
- Forest Ecology and Management GroupWageningen UniversityWageningen6708 PBthe Netherlands
| | - Sabine Braun
- Institute for Applied Plant BiologyWitterswil4108Switzerland
| | - Nina Buchmann
- Department of Environmental Systems ScienceInstitute of Agricultural SciencesETH ZurichZurich8092Switzerland
| | - Werner Eugster
- Department of Environmental Systems ScienceInstitute of Agricultural SciencesETH ZurichZurich8092Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
| | - Matthias Häni
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
| | - Richard L. Peters
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
- Laboratory of Plant EcologyGhent UniversityGhent9000Belgium
| | - Lorenz Walthert
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
| | - Micah Wilhelm
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
| | - Kasia Ziemińska
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
- Department of Plant Ecology and EvolutionUppsala UniversityUppsalaSE‐751 05Sweden
| | - Sophia Etzold
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf8903Switzerland
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17
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Rapid hydraulic collapse as cause of drought-induced mortality in conifers. Proc Natl Acad Sci U S A 2021; 118:2025251118. [PMID: 33846261 DOI: 10.1073/pnas.2025251118] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding the vulnerability of trees to drought-induced mortality is key to predicting the fate of forests in a future climate with more frequent and intense droughts, although the underlying mechanisms are difficult to study in adult trees. Here, we explored the dynamic changes of water relations and limits of hydraulic function in dying adults of Norway spruce (Picea abies L.) during the progression of the record-breaking 2018 Central European drought. In trees on the trajectory to drought-induced mortality, we observed rapid, nonlinear declines of xylem pressure that commenced at the early onset of xylem cavitation and caused a complete loss of xylem hydraulic conductance within a very short time. We also observed severe depletions of nonstructural carbohydrates, though carbon starvation could be ruled out as the cause of the observed tree death, as both dying and surviving trees showed these metabolic limitations. Our observations provide striking field-based evidence for fast dehydration and hydraulic collapse as the cause of drought-induced mortality in adult Norway spruce. The nonlinear decline of tree water relations suggests that considering the temporal dynamics of dehydration is critical for predicting tree death. The collapse of the hydraulic system within a short time demonstrates that trees can rapidly be pushed out of the zone of hydraulic safety during the progression of a severe drought. In summary, our findings point toward a higher mortality risk for Norway spruce than previously assumed, which is in line with current reports of unprecedented levels of drought-induced mortality in this major European tree species.
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18
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A First Assessment of the 2018 European Drought Impact on Ecosystem Evapotranspiration. REMOTE SENSING 2020. [DOI: 10.3390/rs13010016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The combined heatwave and drought in 2018 notably affected the state and functioning of European ecosystems. The severity and distribution of this extreme event across ecosystem types and its possible implication on ecosystem water fluxes are still poorly understood. This study estimates spatio-temporal changes in evapotranspiration (ET) during the 2018 drought and heatwave and assesses how these changes are distributed in European ecosystems along climatic gradients. We used the ET eight-day composite product from the MODerate Resolution Imaging Spectroradiometer (MODIS) together with meteorological data from the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5). Our results indicate that ecosystem ET was strongly reduced (up to −50% compared to a 10-year reference period) in areas with extreme anomalies in surface air temperature (Tsa) and precipitation (P) in central, northern, eastern, and western Europe. Northern and Eastern Europe had prolonged anomalies of up to seven months with extreme intensities (relative and absolute) of Tsa, P, and ET. Particularly, agricultural areas, mixed natural vegetation, and non-irrigated agricultural areas were the most affected by the increased temperatures in northern Europe. Our results show contrasting drought impacts on ecosystem ET between the North and South of Europe as well as on ecosystem types.
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19
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Peters W, Bastos A, Ciais P, Vermeulen A. A historical, geographical and ecological perspective on the 2018 European summer drought. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190505. [PMID: 32892723 DOI: 10.1098/rstb.2019.0505] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Wouter Peters
- Department of Meteorology and Air Quality, Wageningen University, Wageningen, The Netherlands.,Centre for Isotope Research Groningen, Groningen University, Groningen, The Netherlands
| | - Ana Bastos
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
| | - Alex Vermeulen
- Integrated Carbon Observing System (ICOS ERIC), Carbon Portal, Lund, Sweden
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20
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Smith NE, Kooijmans LMJ, Koren G, van Schaik E, van der Woude AM, Wanders N, Ramonet M, Xueref-Remy I, Siebicke L, Manca G, Brümmer C, Baker IT, Haynes KD, Luijkx IT, Peters W. Spring enhancement and summer reduction in carbon uptake during the 2018 drought in northwestern Europe. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190509. [PMID: 32892721 PMCID: PMC7485100 DOI: 10.1098/rstb.2019.0509] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We analysed gross primary productivity (GPP), total ecosystem respiration (TER) and the resulting net ecosystem exchange (NEE) of carbon dioxide (CO2) by the terrestrial biosphere during the summer of 2018 through observed changes across the Integrated Carbon Observation System (ICOS) network, through biosphere and inverse modelling, and through remote sensing. Highly correlated yet independently-derived reductions in productivity from sun-induced fluorescence, vegetative near-infrared reflectance, and GPP simulated by the Simple Biosphere model version 4 (SiB4) suggest a 130–340 TgC GPP reduction in July–August–September (JAS) of 2018. This occurs over an area of 1.6 × 106 km2 with anomalously low precipitation in northwestern and central Europe. In this drought-affected area, reduced GPP, TER, NEE and soil moisture at ICOS ecosystem sites are reproduced satisfactorily by the SiB4 model. We found that, in contrast to the preceding 5 years, low soil moisture is the main stress factor across the affected area. SiB4’s NEE reduction by 57 TgC for JAS coincides with anomalously high atmospheric CO2 observations in 2018, and this is closely matched by the NEE anomaly derived by CarbonTracker Europe (52 to 83 TgC). Increased NEE during the spring (May–June) of 2018 (SiB4 −52 TgC; CTE −46 to −55 TgC) largely offset this loss, as ecosystems took advantage of favourable growth conditions. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.
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Affiliation(s)
- Naomi E Smith
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands
| | - Linda M J Kooijmans
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands
| | - Gerbrand Koren
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands
| | - Erik van Schaik
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands
| | - Auke M van der Woude
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands.,Centre for Isotope Research, University of Groningen, Groningen, The Netherlands
| | - Niko Wanders
- Department of Physical Geography, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Michel Ramonet
- Université Aix Marseille, Université Avignon, CNRS, IRD, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Marseille, France
| | - Irène Xueref-Remy
- Université Aix Marseille, Université Avignon, CNRS, IRD, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Marseille, France
| | - Lukas Siebicke
- University of Göttingen, Bioclimatology, Büsgenweg 2, 37077 Göttingen, Niedersachsen, Germany
| | - Giovanni Manca
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Christian Brümmer
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116 Braunschweig, Germany
| | - Ian T Baker
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
| | - Katherine D Haynes
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
| | - Ingrid T Luijkx
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands
| | - Wouter Peters
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, The Netherlands.,Centre for Isotope Research, University of Groningen, Groningen, The Netherlands
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