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Alderotti F, Verdiani E. God save the queen! How and why the dominant evergreen species of the Mediterranean Basin is declining? AOB PLANTS 2023; 15:plad051. [PMID: 37899973 PMCID: PMC10601391 DOI: 10.1093/aobpla/plad051] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 07/28/2023] [Indexed: 10/31/2023]
Abstract
Quercus ilex may be considered the queen tree of the Mediterranean Basin, dominating coastal forest areas up to 2000 m above sea level at some sites. However, an increase in holm oak decline has been observed in the last decade. In this review, we analysed the current literature to answer the following questions: what are the traits that allow holm oak to thrive in the Mediterranean environment, and what are the main factors that are currently weakening this species? In this framework, we attempt to answer these questions by proposing a triangle as a graphical summary. The first vertex focuses on the main morpho-anatomical, biochemical and physiological traits that allow holm oak to dominate Mediterranean forests. The other two vertices consider abiotic and biotic stressors that are closely related to holm oak decline. Here, we discuss the current evidence of holm oak responses to abiotic and biotic stresses and propose a possible solution to its decline through adequate forest management choices, thus allowing the species to maintain its ecological domain.
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Affiliation(s)
- Francesca Alderotti
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Sesto Fiorentino, Florence 50019, Italy
| | - Erika Verdiani
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Sesto Fiorentino, Florence 50019, Italy
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2
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Martínez-Vilalta J, Poyatos R. Connecting the dots: concurrent assessment of water flows and pools to better understand plant responses to drought. TREE PHYSIOLOGY 2023; 43:1285-1289. [PMID: 37341378 DOI: 10.1093/treephys/tpad076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/08/2023] [Accepted: 06/15/2023] [Indexed: 06/22/2023]
Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Rafael Poyatos
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
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3
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Gori A, Moura BB, Sillo F, Alderotti F, Pasquini D, Balestrini R, Ferrini F, Centritto M, Brunetti C. Unveiling resilience mechanisms of Quercus ilex seedlings to severe water stress: Changes in non-structural carbohydrates, xylem hydraulic functionality and wood anatomy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163124. [PMID: 37001665 DOI: 10.1016/j.scitotenv.2023.163124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 05/13/2023]
Abstract
Over the last few decades, extensive dieback and mortality episodes of Quercus ilex L. have been documented after severe drought events in many Mediterranean forests. However, the underlying physiological, anatomical, and biochemical mechanisms remain poorly understood. We investigated the physiological and biochemical processes linked to embolism formation and non-structural carbohydrates (NSCs) dynamics in Q. ilex seedlings exposed to severe water stress and rewatering. Measurements of leaf gas exchange, water relations, non-structural carbohydrates, drought-related gene expression, and anatomical changes in wood parenchyma were assessed. Under water stress, the midday stem water potential dropped below - 4.5 MPa corresponding to a ~ 50 % loss of hydraulic conductivity. A 70 % reduction in stomatal conductance led to a strong depletion of wood NSCs. Starch consumption, resulting from the upregulation of the β-amylase gene BAM3, together with the downregulation of glucose (GPT1) and sucrose (SUC27) transport genes, suggests glucose utilization to sustain cellular metabolism in the wood parenchyma. After rewatering, the presence of residual xylem embolism led to an incomplete recovery of leaf gas exchanges. However, the partial restoration of photosynthesis allowed the accumulation of new starch reserves in the wood parenchyma and the production of new narrower vessels. In addition, changes in the cell wall composition of the wood parenchyma fibers were observed. Our findings indicate that thirty days of rewatering were sufficient to restore the NSCs reserves and growth rates of Q. ilex seedlings and that the carryover effects of water stress were primarily caused by hydraulic dysfunction.
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Affiliation(s)
- Antonella Gori
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
| | - Barbara Baesso Moura
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Fabiano Sillo
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesca Alderotti
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Dalila Pasquini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Raffaella Balestrini
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesco Ferrini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Mauro Centritto
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Cecilia Brunetti
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
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4
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Wu Y, Wang W, Li W, Zhao S, Wang S, Liu T. Assessment of the spatiotemporal characteristics of vegetation water use efficiency in response to drought in Inner Mongolia, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:6345-6357. [PMID: 35996049 DOI: 10.1007/s11356-022-22622-8] [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: 09/08/2021] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Ecosystem water use efficiency (eWUE) can be used to obtain a better comprehension of the ecosystem water-carbon cycle. This study aimed to characterize the regional-scale responses and adaptations of different vegetation categories to drought changes and the spatiotemporal characteristics of WUE and associated drought factors for nine vegetation categories in Inner Mongolia, China, from 2000 to 2020. This study estimated drought, the association between drought and eWUE among varying vegetation categories, and the differences in eWUE between the drought stage and the post-drought stage by analyzing the spatiotemporal variations in eWUE of different vegetation categories based on MODIS ET (evapotranspiration), GPP (gross primary productivity), and temperature vegetation drought index data. The results illustrated the following: (1) the multi-year mean eWUE from 2000 to 2020 was 1.03 g·m-2·mm-1, with an overall significantly increasing trend of 0.008 g·m-2·mm-1 and eWUE decreasing from northeast to southwest. (2) The rank of vegetation types in Inner Mongolia according to multi-year mean eWUE was evergreen coniferous forest > savanna > evergreen broadleaf forest > forested grassland > farmland > deciduous broadleaf forest > mixed forest > closed scrub > grassland. All vegetation categories illustrated an increasing trend in eWUE over time. (3) eWUE was inversely associated with drought in the drought stage and a clear effect of drought legacy was identified in which harsh drought impacted the eWUE of the ecosystem, whereas eWUE was positively associated with drought. (4) The eWUE values of ecosystems increased significantly after drought, indicating that ecosystems that are adapted to drought show high capacity to recovery from drought stress.
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Affiliation(s)
- Yingjie Wu
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China
| | - Wenjun Wang
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China.
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China.
| | - Wei Li
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China
| | - Shuixia Zhao
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China
| | - Sinan Wang
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, Inner Mongolia, China
| | - Tiejun Liu
- China Institute of Water Resources and Hydropower Research, Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System, Beijing, 100038, China
- Institute of Water Resources for Pastoral Area Ministry of Water Resources, Hohhot, 010020, Inner Mongolia, China
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5
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Haberstroh S, Werner C, Grün M, Kreuzwieser J, Seifert T, Schindler D, Christen A. Central European 2018 hot drought shifts scots pine forest to its tipping point. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1186-1197. [PMID: 35869655 DOI: 10.1111/plb.13455] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
The occurrence of hot drought, i.e. low water availability and simultaneous high air temperature, represents a severe threat to ecosystems. Here, we investigated how the 2018 hot drought in Central Europe caused a tipping point in tree and ecosystem functioning in a Scots pine (Pinus sylvestris L.) forest in southwest Germany. Measurements of stress indicators, such as needle water potential, carbon assimilation and volatile organic compound (VOC) emissions, of dominant P. sylvestris trees were deployed to evaluate tree functioning during hot drought. Ecosystem impact and recovery were assessed as ecosystem carbon exchange, normalized difference vegetation index (NDVI) from satellite data and tree mortality data. During summer 2018, needle water potentials of trees dropped to minimum values of -7.5 ± 0.2 MPa, which implied severe hydraulic impairment of P. sylvestris. Likewise, carbon assimilation and VOC emissions strongly declined after mid-July. Decreasing NDVI values from August 2018 onwards were detected, along with severe defoliation in P. sylvestris, impairing ecosystem carbon flux recovery in 2019, shifting the forest into a year-round carbon source. A total of 47% of all monitored trees (n = 368) died by September 2020. NDVI recovered to pre-2018 levels in 2019, likely caused by emerging broadleaved understorey species. The 2018 hot drought had severe negative impacts on P. sylvestris. The co-occurrence of unfavourable site-specific conditions with recurrent severe droughts resulted in accelerated mortality. Thus, the 2018 hot drought pushed the P. sylvestris stand towards its tipping point, with a subsequent vegetation shift to a broadleaf-dominated forest.
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Affiliation(s)
- S Haberstroh
- Ecosystem Physiology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
| | - C Werner
- Ecosystem Physiology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
| | - M Grün
- Ecosystem Physiology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
| | - J Kreuzwieser
- Ecosystem Physiology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
| | - T Seifert
- Forest Growth and Dendroecology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
- Department of Forest and Wood Science, Stellenbosch University, Matieland, South Africa
| | - D Schindler
- Environmental Meteorology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
| | - A Christen
- Environmental Meteorology, Faculty of Environment and Natural Resources, University Freiburg, Freiburg, Germany
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6
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Precipitation Gradient Drives Divergent Relationship between Non-Structural Carbohydrates and Water Availability in Pinus tabulaeformis of Northern China. FORESTS 2021. [DOI: 10.3390/f12020133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Seasonal non-structural carbohydrate (NSC) dynamics in different organs can indicate the strategies trees use to cope with water stress; however, these dynamics remain poorly understood along a large precipitation gradient. In this study, we hypothesized that the correlation between water availability and NSC concentrations in different organs might be strengthened by decreasing precipitation in Pinus tabulaeformis Carr. forests in temperate China. Our results show that the concentrations of soluble sugars were lower in stems and coarse roots, and starch was higher in branches in the early growing season at drier sites. Throughout the growing season, the concentrations of soluble sugars increased in drier sites, especially for leaves, and remained stable in wetter sites, while starch concentrations were relatively stable in branches and stems at all sites. The NSC concentrations, mainly starch, decreased in coarse roots along the growing season at drier sites. Trees have a faster growth rate with an earlier cessation in active stem growth at drier sites. Interestingly, we also found a divergent relationship between NSCs in different organs and mean growing season water availability, and a stronger correlation was observed in drier sites. These results show that pine forests in arid and semi-arid regions of northern China exhibit different physiological responses to water availability, improving our understanding of the adaptive mechanisms of trees to water limitations in a warmer and drier climate.
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7
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Timofeeva G, Treydte K, Bugmann H, Salmon Y, Rigling A, Schaub M, Vollenweider P, Siegwolf R, Saurer M. How does varying water supply affect oxygen isotope variations in needles and tree rings of Scots pine? TREE PHYSIOLOGY 2020; 40:1366-1380. [PMID: 32589748 DOI: 10.1093/treephys/tpaa082] [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: 10/18/2019] [Revised: 04/01/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
In many regions, drought is suspected to be a cause of Scots pine decline and mortality, but the underlying physiological mechanisms remain unclear. Because of their relationship to ecohydrological processes, δ18O values in tree rings are potentially useful for deciphering long-term physiological responses and tree adaptation to increasing drought. We therefore analyzed both needle- and stem-level isotope fractionations in mature trees exposed to varying water supply. In a first experiment, we investigated seasonal δ18O variations in soil and needle water of Scots pine in a dry inner Alpine valley in Switzerland, comparing drought-stressed trees with trees that were irrigated for more than 10 years. In a second experiment, we analyzed twentieth-century δ18O variations in tree rings of the same forest, including a group of trees that had recently died. We observed less 18O enrichment in needle water of drought-stressed compared with irrigated trees. We applied different isotope fractionation models to explain these results, including the Péclet and the two-pool correction, which considers the ratio of unenriched xylem water in the needles to total needle water. Based on anatomical measurements, we found this ratio to be unchanged in drought-stressed needles, although they were shorter. The observed lower 18O enrichment in needles of stressed trees was therefore likely caused by increased effective path length for water movement within the leaf lamina. In the tree-ring study, we observed lower δ18O values in tree rings of dead trees compared with survivors during several decades prior to their death. These lower values in declining trees are consistent with the lower needle water 18O enrichment observed for drought-stressed compared with irrigated trees, suggesting that this needle-level signal is reflected in the tree rings, although changes in rooting depth could also play a role. Our study demonstrates that long-term effects of drought are reflected in the tree-ring δ18O values, which helps to provide a better understanding of past tree physiological changes of Scots pine.
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Affiliation(s)
- Galina Timofeeva
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
- Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich 8092, Switzerland
| | - Kerstin Treydte
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Harald Bugmann
- Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich 8092, Switzerland
| | - Yann Salmon
- Department of Physics, University of Helsinki, Helsinki 00014, Finland
- School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Andreas Rigling
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Marcus Schaub
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Pierre Vollenweider
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Rolf Siegwolf
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
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8
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Preece C, Farré-Armengol G, Peñuelas J. Drought is a stronger driver of soil respiration and microbial communities than nitrogen or phosphorus addition in two Mediterranean tree species. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 735:139554. [PMID: 32492563 DOI: 10.1016/j.scitotenv.2020.139554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/14/2020] [Accepted: 05/17/2020] [Indexed: 06/11/2023]
Abstract
The drivers of global change, such as increasing drought and nutrient deposition, are affecting soils and their microbial communities in many different habitats, but how these factors interact remains unclear. Quercus ilex and Pinus sylvestris are two important tree species in Mediterranean montane areas that respond differently to drought, which may be associated with the soils in which they grow. We measured soil respiration and physiologically profiled microbial communities to test the impact of drought and subsequent recovery on soil function and diversity for these two species. We also tested whether the addition of nitrogen and phosphorus modified these effects. Drought was the stronger driver of changes to the soil communities, decreasing diversity (Shannon index), and evenness for both species and decreasing soil respiration for Q. ilex when N was added. Soil respiration for P. sylvestris during the drought period was positively affected by N addition but was not affected by water stress. P addition during the drought period did not affect soil respiration for either tree species but did interact with soil-water content to affect community evenness for P. sylvestris. The two species also differed following the recovery from drought. Soil respiration for Q. ilex recovered fully after the drought treatment ended but decreased for P. sylvestris, whereas the soil community was more resilient for P. sylvestris than Q. ilex. Nutrient addition did not affect respiration or community composition or diversity during the recovery period. Soil respiration was generally weakly positively correlated with soil diversity. We demonstrate that short-term water stress and nutrient addition can have variable effects on the soil communities associated with different tree species and that the compositions of the communities can become uncoupled from soil respiration. Overall, we show that drought may be a stronger driver of changes to soil communities than nitrogen or phosphorus deposition.
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Affiliation(s)
- Catherine Preece
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain; CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain.
| | - Gerard Farré-Armengol
- Department of Biosciences, University Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain; CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain
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9
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Jiang P, Meinzer FC, Wang H, Kou L, Dai X, Fu X. Below-ground determinants and ecological implications of shrub species' degree of isohydry in subtropical pine plantations. THE NEW PHYTOLOGIST 2020; 226:1656-1666. [PMID: 32096212 DOI: 10.1111/nph.16502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
The degree of plant iso/anisohydry is a popular framework for characterising species-specific drought responses. However, we know little about associations between below-ground and above-ground hydraulic traits as well as the broader ecological implications of this framework. For 24 understory shrub species in seasonally dry subtropical coniferous plantations, we investigated contributions of the degree of isohydry to species' resource economy strategies, abundance, and importance value, and quantified the hydraulic conductance (Kh ) of above-ground and below-ground organs, magnitude of deep water acquisition (WAdeep ), shallow absorptive root traits (diameter, specific root length, tissue density), and resource-use efficiencies (Amax , maximum photosynthesis rate; PNUE, photosynthetic nitrogen-use efficiency). The extreme isohydric understory species had lower wood density (a proxy for higher growth rates) because their higher WAdeep and whole-plant Kh allowed higher Amax and PNUE, and thus did not necessarily show lower abundance and importance values. Although species' Kh was coordinated with their water foraging capacity in shallow soil, the more acquisitive deep roots were more crucial than shallow roots in shaping species' extreme isohydric behaviour. Our results provide new insights into the mechanisms through which below-ground hydraulic traits, especially those of deep roots, determine species' degree of isohydry and economic strategies.
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Affiliation(s)
- Peipei Jiang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Huimin Wang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Liang Kou
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaoqin Dai
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaoli Fu
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
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10
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Allocation Mechanisms of Non-Structural Carbohydrates of Robinia pseudoacacia L. Seedlings in Response to Drought and Waterlogging. FORESTS 2018. [DOI: 10.3390/f9120754] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Climate change is likely to lead to an increased frequency of droughts and floods, both of which are implicated in large-scale carbon allocation and tree mortality worldwide. Non-structural carbohydrates (NSCs) play an important role in tree survival under stress, but how NSC allocation changes in response to drought or waterlogging is still unclear. We measured soluble sugars (SS) and starch in leaves, twigs, stems and roots of Robinia pseudoacacia L. seedlings that had been subjected to a gradient in soil water availability from extreme drought to waterlogged conditions for a period of 30 days. Starch concentrations decreased and SS concentrations increased in tissues of R. pseudoacacia seedlings, such that the ratio of SS to starch showed a progressive increase under both drought and waterlogging stress. The strength of the response is asymmetric, with the largest increase occurring under extreme drought. While the increase in SS concentration in response to extreme drought is the largest in roots, the increase in the ratio of SS to starch is the largest in leaves. Individual components of SS showed different responses to drought and waterlogging across tissues: glucose concentrations increased significantly with drought in all tissues but showed little response to waterlogging in twigs and stems; sucrose and fructose concentrations showed marked increases in leaves and roots in response to drought but a greater response to drought and waterlogging in stems and twigs. These changes are broadly compatible with the roles of individual SS under conditions of water stress. While it is important to consider the role of NSC in buffering trees against mortality under stress, modelling this behaviour is unlikely to be successful unless it accounts for different responses within organs and the type of stress involved.
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11
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Peters RL, Fonti P, Frank DC, Poyatos R, Pappas C, Kahmen A, Carraro V, Prendin AL, Schneider L, Baltzer JL, Baron-Gafford GA, Dietrich L, Heinrich I, Minor RL, Sonnentag O, Matheny AM, Wightman MG, Steppe K. Quantification of uncertainties in conifer sap flow measured with the thermal dissipation method. THE NEW PHYTOLOGIST 2018; 219:1283-1299. [PMID: 29862531 DOI: 10.1111/nph.15241] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Trees play a key role in the global hydrological cycle and measurements performed with the thermal dissipation method (TDM) have been crucial in providing whole-tree water-use estimates. Yet, different data processing to calculate whole-tree water use encapsulates uncertainties that have not been systematically assessed. We quantified uncertainties in conifer sap flux density (Fd ) and stand water use caused by commonly applied methods for deriving zero-flow conditions, dampening and sensor calibration. Their contribution has been assessed using a stem segment calibration experiment and 4 yr of TDM measurements in Picea abies and Larix decidua growing in contrasting environments. Uncertainties were then projected on TDM data from different conifers across the northern hemisphere. Commonly applied methods mostly underestimated absolute Fd . Lacking a site- and species-specific calibrations reduced our stand water-use measurements by 37% and induced uncertainty in northern hemisphere Fd . Additionally, although the interdaily variability was maintained, disregarding dampening and/or applying zero-flow conditions that ignored night-time water use reduced the correlation between environment and Fd . The presented ensemble of calibration curves and proposed dampening correction, together with the systematic quantification of data-processing uncertainties, provide crucial steps in improving whole-tree water-use estimates across spatial and temporal scales.
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Affiliation(s)
- Richard L Peters
- Landscape Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Department of Environmental Sciences - Botany, Basel University, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Patrick Fonti
- Landscape Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - David C Frank
- Landscape Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Laboratory of Tree-Ring Research, 1215 E. Lowell Street, Tucson, AZ, 8572, USA
- Oeschger Centre for Climate Change Research, Falkenplatz 16, CH-3012, Bern, Switzerland
| | - Rafael Poyatos
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Faculty of Bioscience Engineering, Department of Plants and Crops, Laboratory of Plant Ecology, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
| | - Christoforos Pappas
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montréal, QC, H2V 2B8, Canada
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, Basel University, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Vinicio Carraro
- Department TeSAF Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020, Legnaro, PD, Italy
| | - Angela Luisa Prendin
- Department TeSAF Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020, Legnaro, PD, Italy
- Department of Bioscience, Ecoinformatic & Biodiversity, Aarhus University, Ny Munkegade 116, Building 1540, DK-8000, Aarhus C, Denmark
| | - Loïc Schneider
- Landscape Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Jennifer L Baltzer
- Biology Department, Wilfrid Laurier University, 75 University Ave. W, Waterloo, ON, N2L 3C5, Canada
| | - Greg A Baron-Gafford
- School of Geography and Development, University of Arizona, 1064 E Lowell St, Tucson, AZ, 85719, USA
| | - Lars Dietrich
- Department of Environmental Sciences - Botany, Basel University, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Ingo Heinrich
- Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473, Potsdam, Germany
| | - Rebecca L Minor
- School of Geography and Development, University of Arizona, 1064 E Lowell St, Tucson, AZ, 85719, USA
| | - Oliver Sonnentag
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montréal, QC, H2V 2B8, Canada
| | - Ashley M Matheny
- Department of Geological Sciences, Jackson School of Geosciences, 2305 Speedway Stop, C1160, Austin, TX, USA
| | - Maxwell G Wightman
- College of Forestry, Oregon State University, 1500 SW Jefferson St, Corvallis, OR, 97331, USA
| | - Kathy Steppe
- Faculty of Bioscience Engineering, Department of Plants and Crops, Laboratory of Plant Ecology, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
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12
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Cavitation Limits the Recovery of Gas Exchange after Severe Drought Stress in Holm Oak (Quercus ilex L.). FORESTS 2018. [DOI: 10.3390/f9080443] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Holm oak (Quercus ilex L.) is a Mediterranean species that can withstand intense summer drought through a high resistance to cavitation far beyond the stomatal closure. Besides stomatal limitations, both mesophyll and biochemical limitations to CO2 uptake could increase in holm oak under drought. However, no studies have addressed how hydraulic and non-hydraulic factors may limit the recovery of photosynthesis when re-watering after inducing 50% loss of hydraulic conductivity. We measured photosynthetic traits, xylem embolism, and abscisic acid (ABA) in holm oak with increasing levels of drought stress and seven days after plant re-watering. Drought stress caused a sharp decrease in net CO2 assimilation (AN), stomatal and mesophyll conductance (gs and gm), and maximum velocity of carboxylation (Vcmax). The stomatal closure could be mediated by the rapid increase found in ABA. The high level of xylem embolism explained the strong down-regulation of gs even after re-watering. Therefore, only a partial recovery of AN was observed, in spite of non-hydraulic factors not limiting the recovery of AN, because i/ABA strongly decreased after re-watering, and ii/gm and Vcmax recovered their original values. Therefore, the hydraulic-stomatal limitation model would be involved in the partial recovery of AN, in order to prevent extensive xylem embolism under subsequent drought events that could compromise holm oak survival.
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13
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Wang Q, He Q, Zhou G. Applicability of common stomatal conductance models in maize under varying soil moisture conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 628-629:141-149. [PMID: 29432925 DOI: 10.1016/j.scitotenv.2018.01.291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/28/2018] [Accepted: 01/28/2018] [Indexed: 06/08/2023]
Abstract
In the context of climate warming, the varying soil moisture caused by precipitation pattern change will affect the applicability of stomatal conductance models, thereby affecting the simulation accuracy of carbon-nitrogen-water cycles in ecosystems. We studied the applicability of four common stomatal conductance models including Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (USO) models based on summer maize leaf gas exchange data from a soil moisture consecutive decrease manipulation experiment. The results showed that the USO model performed best, followed by the BBL model, BWB model, and the Jarvis model performed worst under varying soil moisture conditions. The effects of soil moisture made a difference in the relative performance among the models. By introducing a water response function, the performance of the Jarvis, BWB, and USO models improved, which decreased the normalized root mean square error (NRMSE) by 15.7%, 16.6% and 3.9%, respectively; however, the performance of the BBL model was negative, which increased the NRMSE by 5.3%. It was observed that the models of Jarvis, BWB, BBL and USO were applicable within different ranges of soil relative water content (i.e., 55%-65%, 56%-67%, 37%-79% and 37%-95%, respectively) based on the 95% confidence limits. Moreover, introducing a water response function, the applicability of the Jarvis and BWB models improved. The USO model performed best with or without introducing the water response function and was applicable under varying soil moisture conditions. Our results provide a basis for selecting appropriate stomatal conductance models under drought conditions.
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Affiliation(s)
- Qiuling Wang
- College of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China; Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Qijin He
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Guangsheng Zhou
- Chinese Academy of Meteorological Sciences, Beijing 100081, China.
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14
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Choat B, Brodribb TJ, Brodersen CR, Duursma RA, López R, Medlyn BE. Triggers of tree mortality under drought. Nature 2018; 558:531-539. [DOI: 10.1038/s41586-018-0240-x] [Citation(s) in RCA: 647] [Impact Index Per Article: 107.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 05/02/2018] [Indexed: 01/08/2023]
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15
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Effects of Growing-Season Drought on Phenology and Productivity in the West Region of Central Hardwood Forests, USA. FORESTS 2018. [DOI: 10.3390/f9070377] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Cotrozzi L, Remorini D, Pellegrini E, Guidi L, Nali C, Lorenzini G, Massai R, Landi M. Living in a Mediterranean city in 2050: broadleaf or evergreen 'citizens'? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:8161-8173. [PMID: 28616738 DOI: 10.1007/s11356-017-9316-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/19/2017] [Indexed: 05/27/2023]
Abstract
The predicted effects of global change (GC) will be exacerbated in the more densely populated cities of the future, especially in the Mediterranean basin where some environmental cues, such as drought and tropospheric ozone (O3) pollution, already mine seriously plant survival. Physiological and biochemical responses of a Mediterranean, evergreen, isohydric plant species (Quercus ilex) were compared to those of a sympatric, deciduous, anisohydric species (Q. pubescens) under severe drought (20% of the effective daily evapotranspiration) and/or chronic O3 exposure (80 ppb for 5 h day-1 for 28 consecutive days) to test which one was more successful in those highly limiting conditions. Results show that (i) the lower reduction of total leaf biomass of Q. ilex as compared to Q. pubescens when subjected to drought and drought × O3 (on average -59 vs -70%, respectively); (ii) the steeper decline of photosynthesis found in Q. pubescens under drought (-87 vs -81%) and drought × O3 (-69 vs -59%, respectively); (iii) the increments of malondialdehyde (MDA) by-products found only in drought-stressed Q. pubescens; (iv) the impact of O3, found only in Q. pubescens leaves and MDA, can be considered the best probes of the superiority of Q. ilex to counteract the effect of mild-severe drought and O3 stress. Also, an antagonistic effect was found when drought and O3 were applied simultaneously, as usually happens during typical Mediterranean summers. Our dataset suggests that on future, the urban greening should be wisely pondered on the ability of trees to cope the most impacting factors of GC, and in particular their simultaneity.
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Affiliation(s)
- Lorenzo Cotrozzi
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Damiano Remorini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Elisa Pellegrini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
| | - Lucia Guidi
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Cristina Nali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Giacomo Lorenzini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Rossano Massai
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Marco Landi
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
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17
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Huber N, Bugmann H, Lafond V. Global sensitivity analysis of a dynamic vegetation model: Model sensitivity depends on successional time, climate and competitive interactions. Ecol Modell 2018. [DOI: 10.1016/j.ecolmodel.2017.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Effects of Drought on Xylem Anatomy and Water-Use Efficiency of Two Co-Occurring Pine Species. FORESTS 2017. [DOI: 10.3390/f8090332] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Timofeeva G, Treydte K, Bugmann H, Rigling A, Schaub M, Siegwolf R, Saurer M. Long-term effects of drought on tree-ring growth and carbon isotope variability in Scots pine in a dry environment. TREE PHYSIOLOGY 2017; 37:1028-1041. [PMID: 28444356 DOI: 10.1093/treephys/tpx041] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
Drought frequency is increasing in many parts of the world and may enhance tree decline and mortality. The underlying physiological mechanisms are poorly understood, however, particularly regarding chronic effects of long-term drought and the response to increasing temperature and vapor pressure deficit (VPD). We combined analyses of radial growth and stable carbon isotope ratios (δ13C) in tree rings in a mature Scots pine (Pinus sylvestris L.) forest over the 20th century to elucidate causes of tree mortality in one of the driest parts of the European Alps (Pfynwald, Switzerland). We further compared trees that have recently died with living trees in a 10-year irrigation experiment, where annual precipitation was doubled. We found a sustained growth increase and immediate depletion of δ13C values for irrigated trees, indicating higher stomatal conductance and thus indeed demonstrating that water is a key limiting factor for growth. Growth of the now-dead trees started declining in the mid-1980s, when both mean temperature and VPD increased strongly. But growth of these trees was reduced to some extent already several decades earlier, while intrinsic water-use efficiency derived from δ13C values was higher. This indicates a more conservative water-use strategy compared with surviving trees, possibly at the cost of low carbon uptake and long-term reduction of the needle mass. We observed reduced climatic sensitivity of raw tree-ring δ13C for the now-dead in contrast to surviving trees, indicating impaired stomatal regulation, although this difference between the tree groups was smaller after detrending the data. Higher autocorrelation and a lower inter-annual δ13C variability of the now-dead trees further indicates a strong dependence on (low) carbon reserves. We conclude that the recent increase in atmospheric moisture demand in combination with insufficient soil water supply was the main trigger for mortality of those trees that were weakened by long-term reduced carbon uptake.
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Affiliation(s)
- Galina Timofeeva
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232 Villigen PSI, Switzerland
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Kerstin Treydte
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Harald Bugmann
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland
| | - Andreas Rigling
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Marcus Schaub
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Rolf Siegwolf
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232 Villigen PSI, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Matthias Saurer
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232 Villigen PSI, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
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20
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Martínez-Vilalta J, Garcia-Forner N. Water potential regulation, stomatal behaviour and hydraulic transport under drought: deconstructing the iso/anisohydric concept. PLANT, CELL & ENVIRONMENT 2017; 40:962-976. [PMID: 27739594 DOI: 10.1111/pce.12846] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 05/02/2023]
Abstract
In this review, we address the relationship between stomatal behaviour, water potential regulation and hydraulic transport in plants, focusing on the implications for the iso/anisohydric classification of plant drought responses at seasonal timescales. We first revise the history of the isohydric concept and its possible definitions. Then, we use published data to answer two main questions: (1) is greater stomatal control in response to decreasing water availability associated with a tighter regulation of leaf water potential (ΨL ) across species? and (2) is there an association between tighter ΨL regulation (~isohydric behaviour) and lower leaf conductance over time during a drought event? These two questions are addressed at two levels: across species growing in different sites and comparing only species coexisting at a given site. Our analyses show that, across species, a tight regulation of ΨL is not necessarily associated with greater stomatal control or with more constrained assimilation during drought. Therefore, iso/anisohydry defined in terms of ΨL regulation cannot be used as an indicator of a specific mechanism of drought-induced mortality or as a proxy for overall plant vulnerability to drought.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Barcelona, E-08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, E-08193, Spain
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21
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Greenwood S, Ruiz-Benito P, Martínez-Vilalta J, Lloret F, Kitzberger T, Allen CD, Fensham R, Laughlin DC, Kattge J, Bönisch G, Kraft NJB, Jump AS. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area. Ecol Lett 2017; 20:539-553. [PMID: 28220612 DOI: 10.1111/ele.12748] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/23/2016] [Accepted: 01/16/2017] [Indexed: 12/18/2022]
Abstract
Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1 year-1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.
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Affiliation(s)
- Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,Forest Ecology and Restoration Group, Life Sciences Department, Universidad de Alcalá, Science Building, Alcalá de Henares, 28805, Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Francisco Lloret
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, Río Negro, Argentina
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, New Mexico, 87544, USA
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia.,School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Daniel C Laughlin
- Environmental Research Institute and School of Science, University of Waikato, Hamilton, New Zealand
| | - Jens Kattge
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Gerhard Bönisch
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany
| | - Nathan J B Kraft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain
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22
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Barba J, Curiel Yuste J, Poyatos R, Janssens IA, Lloret F. Strong resilience of soil respiration components to drought-induced die-off resulting in forest secondary succession. Oecologia 2016; 182:27-41. [PMID: 26879544 DOI: 10.1007/s00442-016-3567-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 01/21/2016] [Indexed: 11/29/2022]
Abstract
How forests cope with drought-induced perturbations and how the dependence of soil respiration on environmental and biological drivers is affected in a warming and drying context are becoming key questions. The aims of this study were to determine whether drought-induced die-off and forest succession were reflected in soil respiration and its components and to determine the influence of climate on the soil respiration components. We used the mesh exclusion method to study seasonal variations in soil respiration (R S) and its components: heterotrophic (R H) and autotrophic (R A) [further split into fine root (R R) and mycorrhizal respiration (R M)] in a mixed Mediterranean forest where Scots pine (Pinus sylvestris L.) is undergoing a drought-induced die-off and is being replaced by holm oak (Quercus ilex L.). Drought-induced pine die-off was not reflected in R S nor in its components, which denotes a high functional resilience of the plant and soil system to pine die-off. However, the succession from Scots pine to holm oak resulted in a reduction of R H and thus in an important decrease of total respiration (R S was 36 % lower in holm oaks than in non-defoliated pines). Furthermore, R S and all its components were strongly regulated by soil water content-and-temperature interaction. Since Scots pine die-off and Quercus species colonization seems to be widely occurring at the driest limit of the Scots pine distribution, the functional resilience of the soil system over die-off and the decrease of R S from Scots pine to holm oak could have direct consequences for the C balance of these ecosystems.
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Affiliation(s)
- Josep Barba
- CREAF, Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain. .,UnivAutònoma Barcelona (UAB), Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain.
| | | | - Rafael Poyatos
- CREAF, Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain
| | - Ivan A Janssens
- Biology Department, Universiteit Antwerpen, Wilrijk, Antwerpen, 2610, Belgium
| | - Francisco Lloret
- CREAF, Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain.,UnivAutònoma Barcelona (UAB), Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain
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23
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Trade-Offs between Drought Survival and Rooting Strategy of Two South American Mediterranean Tree Species: Implications for Dryland Forests Restoration. FORESTS 2015. [DOI: 10.3390/f6103733] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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