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Safaei M, Kleinebecker T, Weis M, Große-Stoltenberg A. Tracking effects of extreme drought on coniferous forests from space using dynamic habitat indices. Heliyon 2024; 10:e27864. [PMID: 38560251 PMCID: PMC10981029 DOI: 10.1016/j.heliyon.2024.e27864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/27/2024] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
Terrestrial ecosystems such as coniferous forests in Central Europe are experiencing changes in health status following extreme droughts compounding with severe heat waves. The increasing temporal resolution and spatial coverage of earth observation data offer new opportunities to assess these dynamics. Dense time-series of optical satellite data allow for computing Dynamic Habitat Indices (DHIs), which have been predominantly used in biodiversity studies. However, DHIs cover three aspects of vegetation changes that could be affected by drought: annual productivity, minimum cover, and seasonality. Here, we evaluate the health status of coniferous forests in the federal state of Hesse in Germany over the period 2017-2020 including the severe drought year of 2018 using DHIs based on the Normalized Difference Vegetation Index (NDVI) for drought assessment. To identify the most important variables affecting coniferous forest die-off, a series of environmental variables together with the three DHIs components were used in a logistic regression (LR) model. Each DHI component changed significantly across non-damaged and damaged sites in all years (p-value 0.05). When comparing 2017 to 2019, DHI-based annual productivity decreased and seasonality increased. Most importantly, none of the DHI components had reached pre-drought conditions, which likely indicates a change in ecosystem functioning. We also identified spatially explicit areas highly affected by drought. The LR model revealed that in addition to common environmental parameters related to temperature, precipitation, and elevation, DHI components were the most important factors explaining the health status. Our analysis demonstrates the potential of DHIs to capture the effect of drought events on Central European coniferous forest ecosystems. Since the spaceborne data are available at the global level, this approach can be applied to track the dynamics of ecosystem conditions in other regions, at larger spatial scales, and for other Land Use/Land Cover types.
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Affiliation(s)
- Mojdeh Safaei
- Division of Landscape Ecology and Landscape Planning, Institute of Landscape Ecology and Resource Management, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University Giessen, Heinrich-Buff Ring 26-32, 35392, Giessen, Germany
| | - Till Kleinebecker
- Division of Landscape Ecology and Landscape Planning, Institute of Landscape Ecology and Resource Management, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University Giessen, Heinrich-Buff Ring 26-32, 35392, Giessen, Germany
- Center for International Development and Environmental Research (ZEU), Senckenbergstrasse 3, 35390, Giessen, Germany
| | - Manuel Weis
- Hessian Agency for Nature Conservation, Environment and Geology (HLNUG), Rheingaustraße 186, 65203, Wiesbaden, Germany
| | - André Große-Stoltenberg
- Division of Landscape Ecology and Landscape Planning, Institute of Landscape Ecology and Resource Management, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University Giessen, Heinrich-Buff Ring 26-32, 35392, Giessen, Germany
- Center for International Development and Environmental Research (ZEU), Senckenbergstrasse 3, 35390, Giessen, Germany
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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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van der Woude AM, Peters W, Joetzjer E, Lafont S, Koren G, Ciais P, Ramonet M, Xu Y, Bastos A, Botía S, Sitch S, de Kok R, Kneuer T, Kubistin D, Jacotot A, Loubet B, Herig-Coimbra PH, Loustau D, Luijkx IT. Temperature extremes of 2022 reduced carbon uptake by forests in Europe. Nat Commun 2023; 14:6218. [PMID: 37803032 PMCID: PMC10558467 DOI: 10.1038/s41467-023-41851-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 08/30/2023] [Indexed: 10/08/2023] Open
Abstract
The year 2022 saw record breaking temperatures in Europe during both summer and fall. Similar to the recent 2018 drought, close to 30% (3.0 million km2) of the European continent was under severe summer drought. In 2022, the drought was located in central and southeastern Europe, contrasting the Northern-centered 2018 drought. We show, using multiple sets of observations, a reduction of net biospheric carbon uptake in summer (56-62 TgC) over the drought area. Specific sites in France even showed a widespread summertime carbon release by forests, additional to wildfires. Partial compensation (32%) for the decreased carbon uptake due to drought was offered by a warm autumn with prolonged biospheric carbon uptake. The severity of this second drought event in 5 years suggests drought-induced reduced carbon uptake to no longer be exceptional, and important to factor into Europe's developing plans for net-zero greenhouse gas emissions that rely on carbon uptake by forests.
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Affiliation(s)
- Auke M van der Woude
- University of Groningen, Centre for Isotope Research, Groningen, 8481 NG, The Netherlands
- Wageningen University, Meteorology & Air Quality Dept, Wageningen, 6700 AA, The Netherlands
| | - Wouter Peters
- University of Groningen, Centre for Isotope Research, Groningen, 8481 NG, The Netherlands.
- Wageningen University, Meteorology & Air Quality Dept, Wageningen, 6700 AA, The Netherlands.
| | - Emilie Joetzjer
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000, Nancy, France
| | - Sébastien Lafont
- Functional Ecology and Environmental Physics, Ephyse, INRA, Villenave d'Ornon, France
| | - Gerbrand Koren
- Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands
| | - Philippe Ciais
- UMR CEA-CNRS-UVSQ, Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Michel Ramonet
- UMR CEA-CNRS-UVSQ, Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Yidi Xu
- UMR CEA-CNRS-UVSQ, Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Ana Bastos
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | | | - Stephen Sitch
- Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Remco de Kok
- Wageningen University, Meteorology & Air Quality Dept, Wageningen, 6700 AA, The Netherlands
- ICOS ERIC, Carbon Portal, Geocentrum II, Sölvegatan 12, SE-22362, Lund, Sweden
| | - Tobias Kneuer
- Deutscher Wetterdienst, Hohenpeissenberg Meteorological Observatory, Hohenpeissenberg, Germany
| | - Dagmar Kubistin
- Deutscher Wetterdienst, Hohenpeissenberg Meteorological Observatory, Hohenpeissenberg, Germany
| | - Adrien Jacotot
- Sol, Agro et hydrosystèmes, Spatialisation (SAS), UMR 1069, INRAE, Institut Agro, Rennes, France
| | - Benjamin Loubet
- Université Paris Saclay, AgroParisTech, INRAE, UMR 1402 ECOSYS, 91120, Palaiseau, France
| | | | - Denis Loustau
- ISPA, Bordeaux Sciences Agro, INRAE, F-33140, Villenave d'Ornon, France
| | - Ingrid T Luijkx
- Wageningen University, Meteorology & Air Quality Dept, Wageningen, 6700 AA, The Netherlands
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