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Evans MEK, Dey SMN, Heilman KA, Tipton JR, DeRose RJ, Klesse S, Schultz EL, Shaw JD. Tree rings reveal the transient risk of extinction hidden inside climate envelope forecasts. Proc Natl Acad Sci U S A 2024; 121:e2315700121. [PMID: 38830099 DOI: 10.1073/pnas.2315700121] [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: 09/10/2023] [Accepted: 04/03/2024] [Indexed: 06/05/2024] Open
Abstract
Given the importance of climate in shaping species' geographic distributions, climate change poses an existential threat to biodiversity. Climate envelope modeling, the predominant approach used to quantify this threat, presumes that individuals in populations respond to climate variability and change according to species-level responses inferred from spatial occurrence data-such that individuals at the cool edge of a species' distribution should benefit from warming (the "leading edge"), whereas individuals at the warm edge should suffer (the "trailing edge"). Using 1,558 tree-ring time series of an aridland pine (Pinus edulis) collected at 977 locations across the species' distribution, we found that trees everywhere grow less in warmer-than-average and drier-than-average years. Ubiquitous negative temperature sensitivity indicates that individuals across the entire distribution should suffer with warming-the entire distribution is a trailing edge. Species-level responses to spatial climate variation are opposite in sign to individual-scale responses to time-varying climate for approximately half the species' distribution with respect to temperature and the majority of the species' distribution with respect to precipitation. These findings, added to evidence from the literature for scale-dependent climate responses in hundreds of species, suggest that correlative, equilibrium-based range forecasts may fail to accurately represent how individuals in populations will be impacted by changing climate. A scale-dependent view of the impact of climate change on biodiversity highlights the transient risk of extinction hidden inside climate envelope forecasts and the importance of evolution in rescuing species from extinction whenever local climate variability and change exceeds individual-scale climate tolerances.
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Affiliation(s)
- Margaret E K Evans
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721
| | - Sharmila M N Dey
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Kelly A Heilman
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721
| | - John R Tipton
- Statistical Sciences Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - R Justin DeRose
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT 84322
| | - Stefan Klesse
- Forest Dynamics, Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
| | - Emily L Schultz
- Department of Biology, Colorado Mountain College, Breckenridge, CO 80424
| | - John D Shaw
- Riverdale Forestry Sciences Lab, Rocky Mountain Research Station, US Forest Service, Riverdale, UT 84405
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2
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McNichol BH, Wang R, Hefner A, Helzer C, McMahon SM, Russo SE. Topography-driven microclimate gradients shape forest structure, diversity, and composition in a temperate refugial forest. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2024; 5:e10153. [PMID: 38863691 PMCID: PMC11166229 DOI: 10.1002/pei3.10153] [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: 02/13/2024] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 06/13/2024]
Abstract
Macroclimate drives vegetation distributions, but fine-scale topographic variation can generate microclimate refugia for plant persistence in unsuitable areas. However, we lack quantitative descriptions of topography-driven microclimatic variation and how it shapes forest structure, diversity, and composition. We hypothesized that topographic variation and the presence of the forest overstory cause spatiotemporal microclimate variation affecting tree performance, causing forest structure, diversity, and composition to vary with topography and microclimate, and topography and the overstory to buffer microclimate. In a 20.2-ha inventory plot in the North American Great Plains, we censused woody stems ≥1 cm in diameter and collected detailed topographic and microclimatic data. Across 59-m of elevation, microclimate covaried with topography to create a sharp desiccation gradient, and topography and the overstory buffered understory microclimate. The magnitude of microclimatic variation mirrored that of regional-scale variation: with increasing elevation, there was a decrease in soil moisture corresponding to the difference across ~2.1° of longitude along the east-to-west aridity gradient and an increase in air temperature corresponding to the difference across ~2.7° of latitude along the north-to-south gradient. More complex forest structure and higher diversity occurred in moister, less-exposed habitats, and species occupied distinct topographic niches. Our study demonstrates how topographic and microclimatic gradients structure forests in putative climate-change refugia, by revealing ecological processes enabling populations to be maintained during periods of unfavorable macroclimate.
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Affiliation(s)
- Bailey H. McNichol
- School of Biological SciencesUniversity of Nebraska–LincolnLincolnNebraskaUSA
| | - Ran Wang
- School of Natural ResourcesUniversity of Nebraska–LincolnLincolnNebraskaUSA
| | | | | | - Sean M. McMahon
- Smithsonian Institution Forest Global Earth ObservatorySmithsonian Environmental Research CenterEdgewaterMarylandUSA
| | - Sabrina E. Russo
- School of Biological SciencesUniversity of Nebraska–LincolnLincolnNebraskaUSA
- Center for Plant Science InnovationUniversity of Nebraska–LincolnLincolnNebraskaUSA
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3
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Slot M, Rifai SW, Eze CE, Winter K. The stomatal response to vapor pressure deficit drives the apparent temperature response of photosynthesis in tropical forests. THE NEW PHYTOLOGIST 2024. [PMID: 38736030 DOI: 10.1111/nph.19806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/18/2024] [Indexed: 05/14/2024]
Abstract
As temperature rises, net carbon uptake in tropical forests decreases, but the underlying mechanisms are not well understood. High temperatures can limit photosynthesis directly, for example by reducing biochemical capacity, or indirectly through rising vapor pressure deficit (VPD) causing stomatal closure. To explore the independent effects of temperature and VPD on photosynthesis we analyzed photosynthesis data from the upper canopies of two tropical forests in Panama with Generalized Additive Models. Stomatal conductance and photosynthesis consistently decreased with increasing VPD, and statistically accounting for VPD increased the optimum temperature of photosynthesis (Topt) of trees from a VPD-confounded apparent Topt of c. 30-31°C to a VPD-independent Topt of c. 33-36°C, while for lianas no VPD-independent Topt was reached within the measured temperature range. Trees and lianas exhibited similar temperature and VPD responses in both forests, despite 1500 mm difference in mean annual rainfall. Over ecologically relevant temperature ranges, photosynthesis in tropical forests is largely limited by indirect effects of warming, through changes in VPD, not by direct warming effects of photosynthetic biochemistry. Failing to account for VPD when determining Topt misattributes the underlying causal mechanism and thereby hinders the advancement of mechanistic understanding of global warming effects on tropical forest carbon dynamics.
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Affiliation(s)
- Martijn Slot
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
| | - Sami W Rifai
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Chinedu E Eze
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
- Department of Agronomy, Michael Okpara University of Agriculture, Umudike, Abia State, 440109, Nigeria
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
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4
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Elsey-Quirk T, Lynn A, Jacobs MD, Diaz R, Cronin JT, Wang L, Huang H, Justic D. Vegetation dieback in the Mississippi River Delta triggered by acute drought and chronic relative sea-level rise. Nat Commun 2024; 15:3518. [PMID: 38664477 PMCID: PMC11045820 DOI: 10.1038/s41467-024-47828-x] [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: 08/17/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Vegetation dieback and recovery may be dependent on the interplay between infrequent acute disturbances and underlying chronic stresses. Coastal wetlands are vulnerable to the chronic stress of sea-level rise, which may affect their susceptibility to acute disturbance events. Here, we show that a large-scale vegetation dieback in the Mississippi River Delta was precipitated by salt-water incursion during an extreme drought in the summer of 2012 and was most severe in areas exposed to greater flooding. Using 16 years of data (2007-2022) from a coastwide network of monitoring stations, we show that the impacts of the dieback lasted five years and that recovery was only partial in areas exposed to greater inundation. Dieback marshes experienced an increase in percent time flooded from 43% in 2007 to 75% in 2022 and a decline in vegetation cover and species richness over the same period. Thus, while drought-induced high salinities and soil saturation triggered a significant dieback event, the chronic increase in inundation is causing a longer-term decline in cover, more widespread losses, and reduced capacity to recover from acute stressors. Overall, our findings point to the importance of mitigating the underlying stresses to foster resilience to both acute and persistent causes of vegetation loss.
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Affiliation(s)
- Tracy Elsey-Quirk
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA.
| | - Austin Lynn
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Michael Derek Jacobs
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Rodrigo Diaz
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA
| | - James T Cronin
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Lixia Wang
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Haosheng Huang
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Dubravko Justic
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
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5
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Crockett JL, Hurteau MD. Ability of seedlings to survive heat and drought portends future demographic challenges for five southwestern US conifers. TREE PHYSIOLOGY 2024; 44:tpad136. [PMID: 37935402 DOI: 10.1093/treephys/tpad136] [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: 10/27/2023] [Accepted: 11/01/2023] [Indexed: 11/09/2023]
Abstract
Climate change and disturbance are altering forests and the rates and locations of tree regeneration. In semi-arid forests of the southwestern USA, limitations imposed by hot and dry conditions are likely to influence seedling survival. We examined how the survival of 1-year seedlings of five southwestern US conifer species whose southwestern distributions range from warmer and drier woodlands and forests (Pinus edulis Engelm., Pinus ponderosa Douglas ex C. Lawson) to cooler and wetter subalpine forests (Pseudotsuga menziesii (Mirb.) Franco, Abies concolor (Gord. & Glend.) Lindl. Ex Hildebr. and Picea engelmannii Parry ex Engelm.) changed in response to low moisture availability, high temperatures and high vapor pressure deficit in incubators. We used a Bayesian framework to construct discrete-time proportional hazard models that explained 55-75% of the species-specific survival variability. We applied these to the recent climate (1980-2019) of the southwestern USA as well as 1980-2099 CMIP5 climate projections with the RCP8.5 emissions pathway. We found that the more mesic species (i.e., P. menziesii, A. concolor and P. engelmannii) were more susceptible to the effects of hot and dry periods. However, their existing ranges are not projected to experience the conditions we tested as early in the 21st century as the more xeric P. edulis and P. ponderosa, leading to lower percentages of their existing ranges predicted to experience seedling-killing conditions. By late-century, extensive areas of each species southwestern range could experience climate conditions that increase the likelihood of seedling mortality. These results demonstrate that empirically derived physiological limitations can be used to inform where species composition or vegetation type change are likely to occur in the southwestern USA.
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Affiliation(s)
- Joseph L Crockett
- Department of Biology, MSC03-20201, University of New Mexico, Albuquerque, NM 87131-0001
| | - Matthew D Hurteau
- Department of Biology, MSC03-20201, University of New Mexico, Albuquerque, NM 87131-0001
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6
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Beckett HAA, Webb D, Turner M, Sheppard A, Ball MC. Bark water uptake through lenticels increases stem hydration and contributes to stem swelling. PLANT, CELL & ENVIRONMENT 2024; 47:72-90. [PMID: 37811590 DOI: 10.1111/pce.14733] [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: 03/09/2023] [Accepted: 09/26/2023] [Indexed: 10/10/2023]
Abstract
Foliar water uptake can recharge water storage tissue and enable greater hydration than through access to soil water alone; however, few studies have explored the role of the bark in facilitating water uptake. We investigated pathways and dynamics of bark water uptake (BWU) in stems of the mangrove Avicennia marina. We provide novel evidence that specific entry points control dynamics of water uptake through the outer bark surface. Furthermore, using a fluorescent symplastic tracer dye we provide the first evidence that lenticels on the outer bark surface facilitate BWU, thus increasing stem water content by up to 3.7%. X-ray micro-computed tomography showed that BWU was sufficient to cause measurable swelling of stem tissue layers increasing whole stem cross-sectional area by 0.83 mm2 or 2.8%, implicating it as a contributor to the diel patterns of water storage recharge that buffer xylem water potential and maintain hydration of living tissue.
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Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, Australian National University, Canberra, Australia
| | - Michael Turner
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Adrian Sheppard
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
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7
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Wang X, Xu T, Xu C, Liu H, Chen Z, Li Z, Li X, Wu X. Enhanced growth resistance but no decline in growth resilience under long-term extreme droughts. GLOBAL CHANGE BIOLOGY 2024; 30:e17038. [PMID: 37987223 DOI: 10.1111/gcb.17038] [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: 06/23/2023] [Revised: 10/19/2023] [Accepted: 10/29/2023] [Indexed: 11/22/2023]
Abstract
The frequency, intensity, and duration of extreme droughts, with devastating impacts on tree growth and survival, have increased with climate change over the past decades. Assessing growth resistance and resilience to drought is a crucial prerequisite for understanding the responses of forest functioning to drought events. However, the responses of growth resistance and resilience to extreme droughts with different durations across different climatic zones remain unclear. Here, we investigated the spatiotemporal patterns in growth resistance and resilience in response to extreme droughts with different durations during 1901-2015, relying on tree-ring chronologies from 2389 forest stands over the mid- and high-latitudinal Northern Hemisphere, species-specific plant functional traits, and diverse climatic factors. The findings revealed that growth resistance and resilience under 1-year droughts were higher in humid regions than in arid regions. Significant higher growth resistance was observed under 2-year droughts than under 1-year droughts in both arid and humid regions, while growth resilience did not show a significant difference. Temporally, tree growth became less resistant and resilient to 1-year droughts in 1980-2015 than in 1901-1979 in both arid and humid regions. As drought duration lengthened, the predominant impacts of climatic factors on growth resistance and resilience weakened and instead foliar economic traits, plant hydraulic traits, and soil properties became much more important in both climatic regions; in addition, such trends were also observed temporally. Finally, we found that most of the Earth system models (ESMs) used in this study overestimated growth resistance and underestimated growth resilience under both 1-year and 2-year droughts. A comprehensive ecophysiological understanding of tree growth responses to longer and intensified drought events is urgently needed, and a specific emphasis should be placed on improving the performance of ESMs.
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Affiliation(s)
- Xiaona Wang
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Taoran Xu
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Chenxi Xu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Hongyan Liu
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Zhenju Chen
- Tree-Ring Laboratory, Research Station of Liaohe-River Plain Forest Ecosystem CFERN, College of Forestry, Shenyang Agricultural University, Shenyang, China
| | - Zongshan Li
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
- Academy of Plateau Science and Sustainability, People's Government of Qinghai Province & Beijing Normal University, Xining, China
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8
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Heilmayr R, Dudney J, Moore FC. Drought sensitivity in mesic forests heightens their vulnerability to climate change. Science 2023; 382:1171-1177. [PMID: 38060640 DOI: 10.1126/science.adi1071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 10/26/2023] [Indexed: 12/18/2023]
Abstract
Climate change is shifting the structure and function of global forests, underscoring the critical need to predict which forests are most vulnerable to a hotter and drier future. We analyzed 6.6 million tree rings from 122 species to assess trees' sensitivity to water and energy availability. We found that trees growing in wetter portions of their range exhibit the greatest drought sensitivity. To test how these patterns of drought sensitivity influence vulnerability to climate change, we predicted tree growth through 2100. Our results suggest that drought adaptations in arid regions will partially buffer trees against climate change. By contrast, trees growing in the wetter, hotter portions of their climatic range may experience unexpectedly large adverse impacts under climate change.
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Affiliation(s)
- Robert Heilmayr
- Environmental Studies Program, University of California, Santa Barbara, Santa Barbara, CA, USA
- Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Joan Dudney
- Environmental Studies Program, University of California, Santa Barbara, Santa Barbara, CA, USA
- Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Frances C Moore
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA, USA
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9
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Das R, Chaturvedi RK, Roy A, Karmakar S, Ghosh S. Warming inhibits increases in vegetation net primary productivity despite greening in India. Sci Rep 2023; 13:21309. [PMID: 38042916 PMCID: PMC10693629 DOI: 10.1038/s41598-023-48614-3] [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: 06/13/2023] [Accepted: 11/28/2023] [Indexed: 12/04/2023] Open
Abstract
India is the second-highest contributor to the post-2000 global greening. However, with satellite data, here we show that this 18.51% increase in Leaf Area Index (LAI) during 2001-2019 fails to translate into increased carbon uptake due to warming constraints. Our analysis further shows 6.19% decrease in Net Primary Productivity (NPP) during 2001-2019 over the temporally consistent forests in India despite 6.75% increase in LAI. We identify hotspots of statistically significant decreasing trends in NPP over the key forested regions of Northeast India, Peninsular India, and the Western Ghats. Together, these areas contribute to more than 31% of the NPP of India (1274.8 TgC.year-1). These three regions are also the warming hotspots in India. Granger Causality analysis confirms that temperature causes the changes in net-photosynthesis of vegetation. Decreasing photosynthesis and stable respiration, above a threshold temperature, over these regions, as seen in observations, are the key reasons behind the declining NPP. Our analysis shows that warming has already started affecting carbon uptake in Indian forests and calls for improved climate resilient forest management practices in a warming world.
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Affiliation(s)
- Ripan Das
- Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Rajiv Kumar Chaturvedi
- Department of Humanities and Social Sciences, Birla Institute of Technology and Science-Goa Campus, Zuarinagar, India
| | - Adrija Roy
- Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Subhankar Karmakar
- Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
- Environmental Science and Engineering Department, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Subimal Ghosh
- Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India.
- Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India.
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10
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Preisler Y, Grünzweig JM, Ahiman O, Amer M, Oz I, Feng X, Muller JD, Ruehr N, Rotenberg E, Birami B, Yakir D. Vapour pressure deficit was not a primary limiting factor for gas exchange in an irrigated, mature dryland Aleppo pine forest. PLANT, CELL & ENVIRONMENT 2023; 46:3775-3790. [PMID: 37680062 DOI: 10.1111/pce.14712] [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: 06/29/2022] [Accepted: 08/23/2023] [Indexed: 09/09/2023]
Abstract
Climate change is often associated with increasing vapour pressure deficit (VPD) and changes in soil moisture (SM). While atmospheric and soil drying often co-occur, their differential effects on plant functioning and productivity remain uncertain. We investigated the divergent effects and underlying mechanisms of soil and atmospheric drought based on continuous, in situ measurements of branch gas exchange with automated chambers in a mature semiarid Aleppo pine forest. We investigated the response of control trees exposed to combined soil-atmospheric drought (low SM, high VPD) during the rainless Mediterranean summer and that of trees experimentally unconstrained by soil dryness (high SM; using supplementary dry season water supply) but subjected to atmospheric drought (high VPD). During the seasonal dry period, branch conductance (gbr ), transpiration rate (E) and net photosynthesis (Anet ) decreased in low-SM trees but greatly increased in high-SM trees. The response of E and gbr to the massive rise in VPD (to 7 kPa) was negative in low-SM trees and positive in high-SM trees. These observations were consistent with predictions based on a simple plant hydraulic model showing the importance of plant water potential in the gbr and E response to VPD. These results demonstrate that avoiding drought on the supply side (SM) and relying on plant hydraulic regulation constrains the effects of atmospheric drought (VPD) as a stressor on canopy gas exchange in mature pine trees under field conditions.
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Affiliation(s)
- Yakir Preisler
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ori Ahiman
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- Institute of Soil, Water and Environmental Sciences, ARO Volcani Center, Beit Dagan, Israel
| | - Madi Amer
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
| | - Itai Oz
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jonathan D Muller
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
- School for Climate Studies, Stellenbosch University, Stellenbosch, South Africa
| | - Nadine Ruehr
- Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), KIT-Campus Alpin, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | - Eyal Rotenberg
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
| | - Benjamin Birami
- Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), KIT-Campus Alpin, Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | - Dan Yakir
- Department of Earth and Planetary Science, Weizmann Institute of Science, Rehovot, Israel
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11
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Sorek Y, Netzer Y, Cohen S, Hochberg U. Rapid leaf xylem acclimation diminishes the chances of embolism in grapevines. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6836-6846. [PMID: 37659088 DOI: 10.1093/jxb/erad351] [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: 04/09/2023] [Accepted: 09/01/2023] [Indexed: 09/04/2023]
Abstract
Under most conditions tight stomatal regulation in grapevines (Vitis vinifera) avoids xylem embolism. The current study evaluated grapevine responses to challenging scenarios that might lead to leaf embolism and consequential leaf damage. We hypothesized that embolism would occur if the vines experienced low xylem water potential (Ψx) shortly after bud break or later in the season under a combination of extreme drought and heat. We subjected vines to two potentially dangerous environments: (i) withholding irrigation from a vineyard grown in a heatwave-prone environment, and (ii) subjecting potted vines to terminal drought 1 month after bud break. In the field experiment, a heatwave at the beginning of August resulted in leaf temperatures over 45 °C. However, effective stomatal response maintained the xylem water potential (Ψx) well above the embolism threshold, and no leaf desiccation was observed. In the pot experiment, leaves of well-watered vines in May were relatively vulnerable to embolism with 50% embolism (P50) at -1.8 MPa. However, when exposed to drought, these leaves acclimated their leaf P50 by 0.65 MPa in less than a week and before reaching embolism values. When dried to embolizing Ψx, the leaf damage proportion matched (percentage-wise) the leaf embolism level. Our findings indicate that embolism and leaf damage are usually avoided by the grapevines' efficient stomatal regulation and rapid acclimation of their xylem vulnerability.
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Affiliation(s)
- Yonatan Sorek
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Yishai Netzer
- Department of Chemical Engineering, Ariel University, Ariel 40700, Israel
- Eastern R and D Center, Ariel 40700, Israel
| | - Shabtai Cohen
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
| | - Uri Hochberg
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
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12
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He R, Shi H, Hu M, Zhou Q, Zhang Q, Dang H. Divergent effects of warming on nonstructural carbohydrates in woody plants: a meta-analysis. PHYSIOLOGIA PLANTARUM 2023; 175:e14117. [PMID: 38148215 DOI: 10.1111/ppl.14117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/18/2023] [Accepted: 12/01/2023] [Indexed: 12/28/2023]
Abstract
Nonstructural carbohydrates (NSC, including soluble sugars and starch) are essential for supporting growth and survival of woody plants, and play multifunctional roles in various ecophysiological processes that are being rapidly changed by climate warming. However, it still remains unclear whether there is a consistent response pattern of NSC dynamics in woody plants to climate warming across organ types and species taxa. Here, based on a compiled database of 52 woody plant species worldwide, we conducted a meta-analysis to investigate the effects of experimental warming on NSC dynamics. Our results indicated that the responses of NSC dynamics to warming were primarily driven by the fluctuations of starch, while soluble sugars did not undergo significant changes. The effects of warming on NSC shifted from negative to positive with the extension of warming duration, while the negative warming effects on NSC became more pronounced as warming magnitude increased. Overall, our study showed the divergent responses of NSC and its components in different organs of woody plants to experimental warming, suggesting a potentially changed carbon (C) balance in woody plants in future global warming. Thus, our findings highlight that predicting future changes in plant functions and terrestrial C cycle requires a mechanism understanding of how NSC is linked to a specific global change driver.
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Affiliation(s)
- Rui He
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Hang Shi
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
| | - Man Hu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
| | - Quan Zhou
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
| | - Quanfa Zhang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
| | - Haishan Dang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, P.R. China
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13
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Oberhuber W, Gruber A, Wieser G. Seasonal and Daily Xylem Radius Variations in Scots Pine Are Closely Linked to Environmental Factors Affecting Transpiration. BIOLOGY 2023; 12:1251. [PMID: 37759650 PMCID: PMC10525319 DOI: 10.3390/biology12091251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
Seasonal and daily radius variations in the xylem (XRV) and inner bark (IBV) of mature Scots pine trees (Pinus sylvestris) were determined during April 2019-October 2021 at a drought-prone inner alpine site (c. 750 m asl; Tyrol, Austria) by applying point dendrometers. XRVs were also related to environmental factors to evaluate the drivers of XRV during the growing season. XRV records revealed that the xylem width (i) started to shrink around the onset of radial stem growth in April, (ii) consistently decreased by c. 50 µm at the time when air temperature (T) and vapor pressure deficit (VPD) reached their maximum in late June through mid-July, and (iii) recovered until November/December. Although in daily cycles of radius variations XRV preceded IBV by about two hours and the daily amplitude of XRV was about 1/10 that of IBV, XRV and IBV (seasonal trends removed) were closely linked (ρ = 0.755; p < 0.001), indicating tight hydraulic coupling between these tissues. Furthermore, the daily amplitude of XRV was linearly and closely related to daily maximum T (ρ = 0.802; p < 0.001), mean daily solar radiation (ρ = 0.809; p < 0.001), and non-linearly related to daily maximum VPD (R2= 0.837; p < 0.001), indicating that the xylem of Pinus sylvestris reacts like a transpiration-driven passive hydraulic system.
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Affiliation(s)
- Walter Oberhuber
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria; (A.G.); (G.W.)
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14
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Eyland D, Gambart C, Swennen R, Carpentier S. Unravelling the diversity in water usage among wild banana species in response to vapour pressure deficit. FRONTIERS IN PLANT SCIENCE 2023; 14:1068191. [PMID: 37670859 PMCID: PMC10475999 DOI: 10.3389/fpls.2023.1068191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 08/03/2023] [Indexed: 09/07/2023]
Abstract
The rise in global temperature is not only affecting plant functioning directly, but is also increasing air vapour pressure deficit (VPD). The yield of banana is heavily affected by water deficit but so far breeding programs have never addressed the issue of water deficit caused by high VPD. A reduction in transpiration at high VPD has been suggested as a key drought tolerance breeding trait to avoid excessive water loss, hydraulic failure and to increase water use efficiency. In this study, stomatal and transpiration responses under increasing VPD at the leaf and whole-plant level of 8 wild banana (sub)species were evaluated, displaying significant differences in stomatal reactivity. Three different phenotypic groups were identified under increasing VPD. While (sub)species of group III maintained high transpiration rates under increasing VPD, M. acuminata ssp. errans (group I), M. acuminata ssp. zebrina (group II) and M. balbisiana (group II) showed the highest transpiration rate limitations to increasing VPD. In contrast to group I, group II only showed strong reductions at high VPD levels, limiting the cost of reduced photosynthesis and strongly increasing their water use efficiency. M. acuminata ssp. zebrina and M. balbisiana thus show the most favourable responses. This study provides a basis for the identification of potential parent material in gene banks for breeding future-proof bananas that cope better with lack of water.
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Affiliation(s)
- David Eyland
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
| | - Clara Gambart
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
| | - Rony Swennen
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
- International Institute of Tropical Agriculture, Banana Breeding, Kampala, Uganda
| | - Sebastien Carpentier
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Heverlee, Belgium
- Bioversity International, Biodiversity for Food and Agriculture, Leuven, Belgium
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15
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Meyer P, Spînu AP, Mölder A, Bauhus J. Management alters drought-induced mortality patterns in European beech (Fagus sylvatica L.) forests. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1157-1170. [PMID: 35137514 DOI: 10.1111/plb.13396] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The high tree mortality during the dry and hot years of 2018-2019 in Europe has triggered concerns on the future of European beech (Fagus sylvatica L.) forests under climate change and raised questions as to whether forest management may increase tree mortality. We compared long-term mortality rates of beech between managed and unmanaged stands including the years 2018-2019 at 11 sites in Hesse, Germany. We hypothesized that mortality would increase with climate water deficits during the growing season, initial stand density, decreasing dominance of trees, and decreasing intensity of tree removals. Initial stand density, tree removals, the climate water balance and the competitive status of trees were used as predictor variables. Mean annual natural mortality rates ranged between 0.5% and 2.1%. Even in the drought years, we observed no signs of striking canopy disintegration. The significantly higher mortality (1.6-2.1%) in unmanaged stands during the drought years 2018 and 2019 was largely confined to suppressed trees. There was no significant increase of mortality in managed stands during the drought years, but a shift in mortality towards larger canopy trees. Our study did not confirm a general influence of management, in the form of tree removals, on mortality rates. Yet, we found that during drought years, management changed the distribution of mortality within the tree community. To analyse the effects of management on mortality rates more comprehensively, a wider gradient in site moisture conditions, including sites drier than in this study, and longer post-drought periods should be employed.
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Affiliation(s)
- P Meyer
- Department of Forest Nature Conservation, Northwest German Forest Research Institute, Hann. Münden, Germany
| | - A P Spînu
- Chair of Silviculture, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
| | - A Mölder
- Department of Forest Nature Conservation, Northwest German Forest Research Institute, Hann. Münden, Germany
| | - J Bauhus
- Chair of Silviculture, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
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16
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Fang X, Lin T, Zhang B, Lai Y, Chen X, Xiao Y, Xie Y, Zhu J, Yang Y, Wang J. Regulating carbon and water balance as a strategy to cope with warming and drought climate in Cunninghamia lanceolata in southern China. FRONTIERS IN PLANT SCIENCE 2022; 13:1048930. [PMID: 36466246 PMCID: PMC9714357 DOI: 10.3389/fpls.2022.1048930] [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: 09/20/2022] [Accepted: 10/24/2022] [Indexed: 06/17/2023]
Abstract
Human activities have increased the possibility of simultaneous warming and drought, which will lead to different carbon (C) allocation and water use strategies in plants. However, there is no conclusive information from previous studies. To explore C and water balance strategies of plants in response to warming and drought, we designed a 4-year experiment that included control (CT), warming (W, with a 5°C increase in temperature), drought (D, with a 50% decrease in precipitation), and warming and drought conditions (WD) to investigate the non-structural carbohydrate (NSC), C and nitrogen (N) stoichiometry, and intrinsic water use efficiency (iWUE) of leaves, roots, and litter of Cunninghamia lanceolata, a major tree species in southern China. We found that W significantly increased NSC and starch in the leaves, and increased NSC and soluble sugar is one of the components of NSC in the roots. D significantly increased leaves' NSC and starch, and increased litter soluble sugar. The NSC of the WD did not change significantly, but the soluble sugar was significantly reduced. The iWUE of leaves increased under D, and surprisingly, W and D significantly increased the iWUE of litter. The iWUE was positively correlated with NSC and soluble sugar. In addition, D significantly increased N at the roots and litter, resulting in a significant decrease in the C/N ratio. The principal component analysis showed that NSC, iWUE, N, and C/N ratio can be used as identifying indicators for C. lanceolata in both warming and drought periods. This study stated that under warming or drought, C. lanceolata would decline in growth to maintain high NSC levels and reduce water loss. Leaves would store starch to improve the resiliency of the aboveground parts, and the roots would increase soluble sugar and N accumulation to conserve water and to help C sequestration in the underground part. At the same time, defoliation was potentially beneficial for maintaining C and water balance. However, when combined with warming and drought, C. lanceolata growth will be limited by C, resulting in decreased NSC. This study provides a new insight into the coping strategies of plants in adapting to warming and drought environments.
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Affiliation(s)
- Xuan Fang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
| | - Tian Lin
- School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, China
| | - Biyao Zhang
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yongru Lai
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Xupeng Chen
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yixin Xiao
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yiqing Xie
- Institute of Economic Forestry, Fujian Academy of Forestry, Fuzhou, China
| | - Jinmao Zhu
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yusheng Yang
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
- State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University, Fuzhou, China
- School of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Jian Wang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
- School of Geographical Sciences, Fujian Normal University, Fuzhou, China
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17
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No evidence of canopy-scale leaf thermoregulation to cool leaves below air temperature across a range of forest ecosystems. Proc Natl Acad Sci U S A 2022; 119:e2205682119. [PMID: 36095211 PMCID: PMC9499539 DOI: 10.1073/pnas.2205682119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding and predicting the relationship between leaf temperature (Tleaf) and air temperature (Tair) is essential for projecting responses to a warming climate, as studies suggest that many forests are near thermal thresholds for carbon uptake. Based on leaf measurements, the limited leaf homeothermy hypothesis argues that daytime Tleaf is maintained near photosynthetic temperature optima and below damaging temperature thresholds. Specifically, leaves should cool below Tair at higher temperatures (i.e., > ∼25-30°C) leading to slopes <1 in Tleaf/Tair relationships and substantial carbon uptake when leaves are cooler than air. This hypothesis implies that climate warming will be mitigated by a compensatory leaf cooling response. A key uncertainty is understanding whether such thermoregulatory behavior occurs in natural forest canopies. We present an unprecedented set of growing season canopy-level leaf temperature (Tcan) data measured with thermal imaging at multiple well-instrumented forest sites in North and Central America. Our data do not support the limited homeothermy hypothesis: canopy leaves are warmer than air during most of the day and only cool below air in mid to late afternoon, leading to Tcan/Tair slopes >1 and hysteretic behavior. We find that the majority of ecosystem photosynthesis occurs when canopy leaves are warmer than air. Using energy balance and physiological modeling, we show that key leaf traits influence leaf-air coupling and ultimately the Tcan/Tair relationship. Canopy structure also plays an important role in Tcan dynamics. Future climate warming is likely to lead to even greater Tcan, with attendant impacts on forest carbon cycling and mortality risk.
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18
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Wagner Y, Feng F, Yakir D, Klein T, Hochberg U. In situ, direct observation of seasonal embolism dynamics in Aleppo pine trees growing on the dry edge of their distribution. THE NEW PHYTOLOGIST 2022; 235:1344-1350. [PMID: 35514143 PMCID: PMC9541785 DOI: 10.1111/nph.18208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/30/2022] [Indexed: 06/14/2023]
Abstract
Xylem embolism impairs hydraulic conductivity in trees and drives drought-induced mortality. While embolism has been monitored in vivo in potted plants, and research has revealed evidence of embolism in field-grown trees, continuous in situ monitoring of cavitation in forests is lacking. Seasonal patterns of embolism were monitored in branchlets of Aleppo pine (Pinus halepensis) trees growing in a dry Mediterranean forest. Optical visualization (OV) sensors were installed on terminal branches, in addition to monthly sampling for micro computed tomography scans. We detected 208 cavitation events among four trees, which represented an embolism increase from zero to c. 12% along the dry season. Virtually all the cavitation events occurred during daytime hours, with 77% occurring between 10:00 and 17:00 h. The probability for cavitation in a given hour increased as vapor pressure deficit (VPD) increased, up to a probability of 42% for cavitation when VPD > 5 kPa. The findings uniquely reveal the instantaneous environmental conditions that lead to cavitation. The increased likelihood of cavitation events under high VPD in water-stressed pines is the first empirical support for this long hypothesized relationship. Our observations suggest that low levels of embolism are common in Aleppo pine trees at the dry edge of their distribution.
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Affiliation(s)
- Yael Wagner
- Plant & Environmental Sciences DepartmentWeizmann Institute of ScienceRehovot7610001Israel
| | - Feng Feng
- Institute of Soil, Water and Environmental SciencesVolcani CenterARORishon Lezion7505101Israel
| | - Dan Yakir
- Earth and Planetary Science DepartmentWeizmann Institute of ScienceRehovot7610001Israel
| | - Tamir Klein
- Plant & Environmental Sciences DepartmentWeizmann Institute of ScienceRehovot7610001Israel
| | - Uri Hochberg
- Institute of Soil, Water and Environmental SciencesVolcani CenterARORishon Lezion7505101Israel
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19
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Rising ecosystem water demand exacerbates the lengthening of tropical dry seasons. Nat Commun 2022; 13:4093. [PMID: 35835788 PMCID: PMC9283447 DOI: 10.1038/s41467-022-31826-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 07/01/2022] [Indexed: 11/18/2022] Open
Abstract
Precipitation-based assessments show a lengthening of tropical dry seasons under climate change, without considering simultaneous changes in ecosystem water demand. Here, we compare changes in tropical dry season length and timing when dry season is defined as the period when precipitation is less than: its climatological average, potential evapotranspiration, or actual evapotranspiration. While all definitions show more widespread tropical drying than wetting for 1983-2016, we find the largest fraction (48.7%) of tropical land probably experiencing longer dry seasons when dry season is defined as the period when precipitation cannot meet the need of actual evapotranspiration. Southern Amazonia (due to delayed end) and central Africa (due to earlier onset and delayed end) are hotspots of dry season lengthening, with greater certainty when accounting for water demand changes. Therefore, it is necessary to account for changing water demand when characterizing changes in tropical dry periods and ecosystem water deficits. Changing precipitation pattern has been suggested to expand tropical dry seasons. Here, the authors show that this lengthening can be even more severe when accounting for the simultaneous rise of ecosystem water demand in a warmer climate.
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20
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Blasini DE, Koepke DF, Bush SE, Allan GJ, Gehring CA, Whitham TG, Day TA, Hultine KR. Tradeoffs between leaf cooling and hydraulic safety in a dominant arid land riparian tree species. PLANT, CELL & ENVIRONMENT 2022; 45:1664-1681. [PMID: 35147232 DOI: 10.1111/pce.14292] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Leaf carbon gain optimization in hot environments requires balancing leaf thermoregulation with avoiding excessive water loss via transpiration and hydraulic failure. The tradeoffs between leaf thermoregulation and transpirational water loss can determine the ecological consequences of heat waves that are increasing in frequency and intensity. We evaluated leaf thermoregulation strategies in warm- (>40°C maximum summer temperature) and cool-adapted (<40°C maximum summer temperature) genotypes of the foundation tree species, Populus fremontii, using a common garden near the mid-elevational point of its distribution. We measured leaf temperatures and assessed three modes of leaf thermoregulation: leaf morphology, midday canopy stomatal conductance and stomatal sensitivity to vapour pressure deficit. Data were used to parameterize a leaf energy balance model to estimate contrasts in midday leaf temperature in warm- and cool-adapted genotypes. Warm-adapted genotypes had 39% smaller leaves and 38% higher midday stomatal conductance, reflecting a 3.8°C cooler mean leaf temperature than cool-adapted genotypes. Leaf temperatures modelled over the warmest months were on average 1.1°C cooler in warm- relative to cool-adapted genotypes. Results show that plants adapted to warm environments are predisposed to tightly regulate leaf temperatures during heat waves, potentially at an increased risk of hydraulic failure.
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Affiliation(s)
- Davis E Blasini
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Dan F Koepke
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
| | - Susan E Bush
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
| | - Gerard J Allan
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Catherine A Gehring
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Thomas G Whitham
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Thomas A Day
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
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21
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Modern aridity in the Altai-Sayan mountain range derived from multiple millennial proxies. Sci Rep 2022; 12:7752. [PMID: 35562178 PMCID: PMC9095625 DOI: 10.1038/s41598-022-11299-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/11/2022] [Indexed: 11/18/2022] Open
Abstract
Temperature and precipitation changes are crucial for larch trees growing at high-elevation sites covered by permafrost in the Altai-Sayan mountain range (ASMR). To contextualize the amplitude of recent climate fluctuations, we have to look into the past by analyzing millennial paleoclimatic archives recording both temperature and precipitation. We developed annually resolved 1500-year tree-ring cellulose chronologies (δ13Ccell, δ18Ocell), and used these new records to reconstruct the variability in local summer precipitation and air temperature. We combined our new local reconstructions with existing paleoclimatic archives available for the Altai. The data show a strong decreasing trend by ca. 49% in regional summer precipitation, along with a regional summer temperature increase towards the twenty-first century, relative to the preceding 1500 years. Modern dry conditions (1966–2016 CE) in the ASMR are the result of simultaneous summer warming and decreased precipitation. Our new reconstructions also demonstrate that climate change in the ASMR is much stronger compared to the global average.
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22
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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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23
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Karatassiou M, Karaiskou P, Verykouki E, Rhizopoulou S. Hydraulic Response of Deciduous and Evergreen Broadleaved Shrubs, Grown on Olympus Mountain in Greece, to Vapour Pressure Deficit. PLANTS 2022; 11:plants11081013. [PMID: 35448741 PMCID: PMC9030577 DOI: 10.3390/plants11081013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 11/25/2022]
Abstract
In this study, leaf hydraulic functionality of co-occurring evergreen and deciduous shrubs, grown on Olympus Mountain, has been compared. Four evergreen species (Arbutus andrachne, Arbutus unedo, Quercus ilex and Quercus coccifera) and four deciduous species (Carpinus betulus, Cercis siliquastrum, Coronilla emeroides and Pistacia terebinthus) were selected for this study. Predawn and midday leaf water potential, transpiration, stomatal conductance, leaf temperature and leaf hydraulic conductance were estimated during the summer period. The results demonstrate different hydraulic tactics between the deciduous and evergreen shrubs. Higher hydraulic conductance and lower stomatal conductance were obtained in deciduous plants compared to the evergreens. Additionally, positive correlations were detected between water potential and transpiration in the deciduous shrubs. The seasonal leaf hydraulic conductance declined in both deciduous and evergreens under conditions of elevated vapor pressure deficit during the summer; however, at midday, leaf water potential reached comparable low values, but the deciduous shrubs exhibited higher hydraulic conductance compared to the evergreens. It seems likely that hydraulic traits of the coexisting evergreen and deciduous plants indicate water spending and saving tactics, respectively; this may also represent a limit to drought tolerance of these species grown in a natural environment, which is expected to be affected by global warming.
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Affiliation(s)
- Maria Karatassiou
- Laboratory of Rangeland Ecology, School of Forestry and Natural Environment, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
- Correspondence: ; Tel.: +30-2310-992302
| | - Panagiota Karaiskou
- Laboratory of Rangeland Ecology, School of Forestry and Natural Environment, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Eleni Verykouki
- Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, Fytokou St., 38446 Volos, Greece;
| | - Sophia Rhizopoulou
- Section of Botany, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece;
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Hammond WM, Williams AP, Abatzoglou JT, Adams HD, Klein T, López R, Sáenz-Romero C, Hartmann H, Breshears DD, Allen CD. Global field observations of tree die-off reveal hotter-drought fingerprint for Earth's forests. Nat Commun 2022; 13:1761. [PMID: 35383157 PMCID: PMC8983702 DOI: 10.1038/s41467-022-29289-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
Earth's forests face grave challenges in the Anthropocene, including hotter droughts increasingly associated with widespread forest die-off events. But despite the vital importance of forests to global ecosystem services, their fates in a warming world remain highly uncertain. Lacking is quantitative determination of commonality in climate anomalies associated with pulses of tree mortality-from published, field-documented mortality events-required for understanding the role of extreme climate events in overall global tree die-off patterns. Here we established a geo-referenced global database documenting climate-induced mortality events spanning all tree-supporting biomes and continents, from 154 peer-reviewed studies since 1970. Our analysis quantifies a global "hotter-drought fingerprint" from these tree-mortality sites-effectively a hotter and drier climate signal for tree mortality-across 675 locations encompassing 1,303 plots. Frequency of these observed mortality-year climate conditions strongly increases nonlinearly under projected warming. Our database also provides initial footing for further community-developed, quantitative, ground-based monitoring of global tree mortality.
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Affiliation(s)
- William M. Hammond
- grid.15276.370000 0004 1936 8091Agronomy Department, University of Florida, Gainesville, FL 32611 USA
| | - A. Park Williams
- grid.19006.3e0000 0000 9632 6718Department of Geography, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - John T. Abatzoglou
- grid.266096.d0000 0001 0049 1282Management of Complex Systems, University of California, Merced, CA USA
| | - Henry D. Adams
- grid.30064.310000 0001 2157 6568School of the Environment, Washington State University, Pullman, WA USA
| | - Tamir Klein
- grid.13992.300000 0004 0604 7563Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Rosana López
- grid.5690.a0000 0001 2151 2978Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | - Cuauhtémoc Sáenz-Romero
- grid.412205.00000 0000 8796 243XInstituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán Mexico
| | - Henrik Hartmann
- grid.419500.90000 0004 0491 7318Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - David D. Breshears
- grid.134563.60000 0001 2168 186XSchool of Natural Resources and the Environment, University of Arizona, Tucson, AZ USA
| | - Craig D. Allen
- grid.266832.b0000 0001 2188 8502Department of Geography and Environmental Studies, University of New Mexico, Albuquerque, NM USA
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Lee EH, Beedlow PA, Brooks JR, Tingey DT, Wickham C, Rugh W. Physiological responses of Douglas-fir to climate and forest disturbances as detected by cellulosic carbon and oxygen isotope ratios. TREE PHYSIOLOGY 2022; 42:5-25. [PMID: 34528693 PMCID: PMC9394118 DOI: 10.1093/treephys/tpab122] [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: 09/23/2019] [Revised: 11/19/2020] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Swiss needle cast (SNC), caused by a fungal pathogen, Nothophaeocryptopus gaeumannii, is a major forest disease of Douglas-fir (Pseudotsuga menziesii) stands of the Pacific Northwest (PNW). There is mounting concern that the current SNC epidemic occurring in Oregon and Washington will continue to increase in severity, frequency and spatial extent with future warming. Nothophaeocryptopus gaeumannii occurs wherever its host is found, but very little is known about the history and spatial distribution of SNC and its effects on growth and physiological processes of mature and old-growth forests within the Douglas-fir region of the PNW. Our findings show that stem growth and physiological responses of infected Douglas-fir to climate and SNC were different between sites, growth periods and disease severity based on cellulosic stable carbon and oxygen isotope ratios and ring width data in tree rings. At a coastal Oregon site within the SNC impact zone, variations in stem growth and Δ13C were primarily influenced by disproportional reductions in stomatal conductance (gs) and assimilation (A) caused by a loss of functioning stomates through early needle abscission and stomatal occlusion by pseudothecia of N. gaeumannii. At the less severely infected inland sites on the west slopes of Oregon's Cascade Range, stem growth correlated negatively with δ18O and positively with Δ13C, indicating that gs decreased in response to high evaporative demand with a concomitant reduction in A. Current- and previous-years summer vapor pressure deficit was the principal seasonal climatic variable affecting radial stem growth and the dual stable isotope ratios at all sites. Our results indicate that rising temperatures since the mid-1970s has strongly affected Douglas-fir growth in the PNW directly by a physiological response to higher evaporative demand during the annual summer drought and indirectly by a major SNC epidemic that is expanding regionally to higher latitudes and higher elevations.
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Affiliation(s)
- Edward Henry Lee
- US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR 97333, USA
| | - Peter A. Beedlow
- US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR 97333, USA
| | - J. Renée Brooks
- US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR 97333, USA
| | - David T. Tingey
- US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR 97333, USA
- Retired
| | - Charlotte Wickham
- Oregon State University, Department of Statistics, Weniger Hall Room 255, Corvallis, OR 97331, USA
| | - William Rugh
- US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR 97333, USA
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Pasqualotto G, Carraro V, Suarez Huerta E, Anfodillo T. Assessment of Canopy Conductance Responses to Vapor Pressure Deficit in Eight Hazelnut Orchards Across Continents. FRONTIERS IN PLANT SCIENCE 2021; 12:767916. [PMID: 34956266 PMCID: PMC8692988 DOI: 10.3389/fpls.2021.767916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
A remarkable increase in vapor pressure deficit (VPD) has been recorded in the last decades in relation to global warming. Higher VPD generally leads to stomatal closure and limitations to leaf carbon uptake. Assessing tree conductance responses to VPD is a key step for modeling plant performances and productivity under future environmental conditions, especially when trees are cultivated well outside their native range as for hazelnut (Corylus spp.). Our main aim is to assess the stand-level surface canopy conductance (G surf ) responses to VPD in hazelnut across different continents to provide a proxy for potential productivity. Tree sap flow (Fd) was measured by Thermal dissipation probes (TDP) probes (six per sites) in eight hazelnut orchards in France, Italy, Georgia, Australia, and Chile during three growing seasons since 2016, together with the main meteorological parameters. We extracted diurnal Fd to estimate the canopy conductance G surf. . In all the sites, the maximum G surf occurred at low values of VPD (on average 0.57 kPa) showing that hazelnut promptly avoids leaf dehydration and that maximum leaf gas exchange is limited at relatively low VPD (i.e., often less than 1 kPa). The sensitivity of the conductance vs. VPD (i.e., -dG/dlnVPD) resulted much lower (average m = -0.36) compared to other tree species, with little differences among sites. We identified a range of suboptimal VPD conditions for G surf maximization (G surf > 80% compared to maximum) in each site, named "VPD80," which multiplied by the mean G surf might be used as a proxy for assessing the maximum gas exchange of the orchard with a specific management and site. Potential gas exchange appeared relatively constant in most of the sites except in France (much higher) and in the driest Australian site (much lower). This study assessed the sensitivity of hazelnut to VPD and proposed a simple proxy for predicting the potential gas exchange in different areas. Our results can be used for defining suitability maps based on average VPD conditions, thus facilitating correct identification of the potentially most productive sites.
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Affiliation(s)
- Gaia Pasqualotto
- Forest Ecology Research Unit, Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Legnaro, Italy
| | - Vinicio Carraro
- Forest Ecology Research Unit, Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Legnaro, Italy
| | - Eloy Suarez Huerta
- Hazelnut Company Division, Ferrero Trading Luxembourg, Findel, Luxembourg
| | - Tommaso Anfodillo
- Forest Ecology Research Unit, Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Legnaro, Italy
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27
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Quantifying the mitigation of temperature extremes by forests and wetlands in a temperate landscape. ECOL INFORM 2021. [DOI: 10.1016/j.ecoinf.2021.101442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Vitali V, Klesse S, Weigt R, Treydte K, Frank D, Saurer M, Siegwolf RTW. High-frequency stable isotope signals in uneven-aged forests as proxy for physiological responses to climate in Central Europe. TREE PHYSIOLOGY 2021; 41:2046-2062. [PMID: 33960372 DOI: 10.1093/treephys/tpab062] [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: 10/20/2020] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Picea abies (L.) Karst. and Fagus sylvatica (L.) are important tree species in Europe, and the foreseen increase in temperature and vapour pressure deficit (VPD) could increase the vulnerability of these species. However, their physiological performance under climate change at temperate and productive sites is not yet fully understood, especially in uneven-aged stands. Therefore, we investigated tree-ring width and stable isotope chronologies (δ13C/δ18O) of these two species at 10 sites along a climate gradient in Central Europe. In these uneven-aged stands, we compared the year-to-year variability of dominant and suppressed trees for the last 80 years in relation to the sites' spatial distribution and climate. δ18O and δ13C were generally consistent across sites and species, showing high sensitivity to summer VPD, whereas climate correlations with radial growth varied much more and depended on mean local climate. We found no significant differences between dominant and suppressed trees in the response of stable isotope ratios to climate variability, especially within the annual high-frequency signals. In addition, we observed a strikingly high coherence of the high-frequency δ18O variations across long distances with significant correlations above 1500 km, whereas the spatial agreement of δ13C variations was weaker (~700 km). We applied a dual-isotope approach that is based on known theoretical understanding of isotope fractionations to translate the observed changes into physiological components, mainly photosynthetic assimilation rate and stomatal conductance. When separating the chronologies in two time windows and investigating the shifts in isotopes ratios, a significant enrichment of either or both isotope ratios over the last decades can be observed. These results, translated by the dual-isotope approach, indicate a general climate-driven decrease in stomatal conductance. This improved understanding of the physiological mechanisms controlling the short-term variation of the isotopic signature will help to define the performance of these tree species under future climate.
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Affiliation(s)
- Valentina Vitali
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - Stefan Klesse
- Swiss Forest Protection, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Forest Resources and Management, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - Rosemarie Weigt
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Kerstin Treydte
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - David Frank
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ 85721, USA
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Rolf T W Siegwolf
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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29
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Ranawana SRWMCJK, Siddique KHM, Palta JA, Stefanova K, Bramley H. Stomata coordinate with plant hydraulics to regulate transpiration response to vapour pressure deficit in wheat. FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:839-850. [PMID: 33934747 DOI: 10.1071/fp20392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Genotypic variation in transpiration (Tr) response to vapour pressure deficit (VPD) has been studied in many crop species. There is debate over whether shoots or roots drive these responses. We investigated how stomata coordinate with plant hydraulics to mediate Tr response to VPD and influence leaf water status in wheat (Triticum aestivum L.). We measured Tr and stomatal conductance (gs) responses to VPD in well-watered, water-stressed and de-rooted shoots of eight wheat genotypes. Tr response to VPD was related to stomatal sensitivity to VPD and proportional to gs at low VPD, except in the water-stressed treatment, which induced strong stomatal closure at all VPD levels. Moreover, gs response to VPD was driven by adaxial stomata. A simple linear Tr response to VPD was associated with unresponsive gs to VPD. In contrast, segmented linear Tr to VPD response was mostly a function of gs with the breakpoint depending on the capacity to meet transpirational demand and set by the shoots. However, the magnitude of Tr response to VPD was influenced by roots, soil water content and stomatal sensitivity to VPD. These findings, along with a theoretical model suggest that stomata coordinate with plant hydraulics to regulate Tr response to VPD in wheat.
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Affiliation(s)
- S R W M C J K Ranawana
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia; and Department of Export Agriculture, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Badulla 90000, Sri Lanka; and Corresponding author.
| | - K H M Siddique
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
| | - J A Palta
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia; and CSIRO Agriculture, Private Bag No. 5, Wembley, WA 6913, Australia
| | - K Stefanova
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
| | - H Bramley
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia; and Plant Breeding Institute, School of Life and Environmental Sciences, The University of Sydney, Narrabri, NSW 2390, Australia
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30
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Breshears DD, Fontaine JB, Ruthrof KX, Field JP, Feng X, Burger JR, Law DJ, Kala J, Hardy GESJ. Underappreciated plant vulnerabilities to heat waves. THE NEW PHYTOLOGIST 2021; 231:32-39. [PMID: 33728638 DOI: 10.1111/nph.17348] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
With climate change, heat waves are becoming increasingly frequent, intense and broader in spatial extent. However, while the lethal effects of heat waves on humans are well documented, the impacts on flora are less well understood, perhaps except for crops. We summarize recent findings related to heat wave impacts including: sublethal and lethal effects at leaf and plant scales, secondary ecosystem effects, and more complex impacts such as increased heat wave frequency across all seasons, and interactions with other disturbances. We propose generalizable practical trials to quantify the critical bounding conditions of vulnerability to heat waves. Collectively, plant vulnerabilities to heat waves appear to be underappreciated and understudied, particularly with respect to understanding heat wave driven plant die-off and ecosystem tipping points.
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Affiliation(s)
- David D Breshears
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Joseph B Fontaine
- Environmental and Conservation Sciences, Murdoch University, Murdoch, WA, 6150, Australia
| | - Katinka X Ruthrof
- Environmental and Conservation Sciences, Murdoch University, Murdoch, WA, 6150, Australia
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, 6151, Australia
| | - Jason P Field
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Xiao Feng
- Department of Geography, Florida State University, Tallahassee, FL, 32306, USA
| | - Joseph R Burger
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Arizona Institutes for Resilience, University of Arizona, Tucson, AZ, 85721, USA
| | - Darin J Law
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Jatin Kala
- Environmental and Conservation Sciences, Murdoch University, Murdoch, WA, 6150, Australia
- Centre for Climate-Impacted Terrestrial Ecosystems, Harry Butler Institute, Murdoch University, Murdoch, WA, Australia
| | - Giles E St J Hardy
- Environmental and Conservation Sciences, Murdoch University, Murdoch, WA, 6150, Australia
- Centre for Climate-Impacted Terrestrial Ecosystems, Harry Butler Institute, Murdoch University, Murdoch, WA, Australia
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31
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Adhikari A, Masters RE, Mainali KP, Zou CB, Joshi O, Will RE. Management and climate variability effects on understory productivity of forest and savanna ecosystems in Oklahoma, USA. Ecosphere 2021. [DOI: 10.1002/ecs2.3576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Arjun Adhikari
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater Oklahoma74078USA
| | - Ronald E. Masters
- College of Natural Resources University of Wisconsin‐Stevens Point Stevens Point Wisconsin54481USA
| | - Kumar P. Mainali
- Conservation Innovation Center Chesapeake Conservancy Annapolis Maryland21401USA
| | - Chris B. Zou
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater Oklahoma74078USA
| | - Omkar Joshi
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater Oklahoma74078USA
| | - Rodney E. Will
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater Oklahoma74078USA
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32
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Olson ME, Anfodillo T, Rosell JA, Martínez-Méndez N. Across climates and species, higher vapour pressure deficit is associated with wider vessels for plants of the same height. PLANT, CELL & ENVIRONMENT 2020; 43:3068-3080. [PMID: 32909290 DOI: 10.1111/pce.13884] [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: 07/17/2019] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
While plant height is the main driver of variation in mean vessel diameter at the stem base (VD) across angiosperms, climate, specifically temperature, does play an explanatory role, with vessels being wider with warmer temperature for plants of the same height. Using a comparative approach sampling 537 species of angiosperms across 19 communities, we rejected selection favouring freezing-induced embolism resistance as being able to account for wider vessels for a given height in warmer climates. Instead, we give reason to suspect that higher vapour pressure deficit (VPD) accounts for the positive scaling of height-standardized VD (and potential xylem conductance) with temperature. Selection likely favours conductive systems that are able to meet the higher transpirational demand of warmer climates, which have higher VPD, resulting in wider vessels for a given height. At the same time, wider vessels are likely more vulnerable to dysfunction. With future climates likely to experience ever greater extremes of VPD, future forests could be increasingly vulnerable.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Departamento de Botánica, Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Padova, Italy
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Norberto Martínez-Méndez
- Laboratorio de Bioconservación y Manejo, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Unidad Profesional Lázaro Cárdenas, Ciudad de México, Mexico
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33
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Tepley AJ, Hood SM, Keyes CR, Sala A. Forest restoration treatments in a ponderosa pine forest enhance physiological activity and growth under climatic stress. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02188. [PMID: 32492227 DOI: 10.1002/eap.2188] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/28/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
As the climate warms, drought will increasingly occur under elevated temperatures, placing forest ecosystems at growing risk of extensive dieback and mortality. In some cases, increases in tree density following early 20th-century fire suppression may exacerbate this risk. Treatments designed to restore historical stand structure and enhance resistance to high-severity fire might also alleviate drought stress by reducing competition, but the duration of these effects and the underlying mechanisms remain poorly understood. To elucidate these mechanisms, we evaluate tree growth, mortality, and tree-ring stable-carbon isotope responses to stand-density reduction treatments with and without prescribed fire in a ponderosa pine forest of western Montana. Moderate and heavier cutting experiments (basal area reductions of 35% and 56%, respectively) were initiated in 1992, followed by prescribed burning in a subset of the thinned units. All treatments led to a growth release that persisted to the time of resampling. The treatments had little effect on climate-growth relationships, but they markedly altered seasonal carbon isotope signals and their relationship to climate. In burned and unburned treatments, carbon isotope discrimination (Δ13 C) increased in the earlywood (EW) and decreased in the latewood (LW) relative to the control. The sensitivity of LW Δ13 C to late-summer climate also increased in all treatments, but not in the control. Such increased sensitivity indicates that the reduction in competition enabled trees to continue to fix carbon for new stem growth, even when the climate became sufficiently stressful to stop new assimilation in slower-growing trees in untreated units. These findings would have been masked had we not separated EW and LW. The importance of faster growth and enhanced carbon assimilation under late-summer climatic stress became evident in the second decade post-treatment, when mountain pine beetle activity increased locally, and tree mortality rates in the controls of both experiments increased to more than twice those in their respective treatments. These findings highlight that, when thinning is used to restore historical forest structure or increase resistance to high-severity fire, there will likely be additional benefits of enhanced growth and physiological activity under climatic stress, and the effects may persist for more than two decades.
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Affiliation(s)
- Alan J Tepley
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, USA
- W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, Montana, 59812, USA
| | - Sharon M Hood
- Fire, Fuel and Smoke Science Program, Rocky Mountain Research Station, USDA Forest Service, Missoula, Montana, 59808, USA
| | - Christopher R Keyes
- W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, Montana, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, USA
- W.A. Franke College of Forestry & Conservation, University of Montana, Missoula, Montana, 59812, USA
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34
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Influence of Warmer and Drier Environmental Conditions on Species-Specific Stem Circumference Dynamics and Water Status of Conifers in Submontane Zone of Central Slovakia. WATER 2020. [DOI: 10.3390/w12102945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The frequency and intensity of droughts and heatwaves in Europe with notable impact on forest growth are expected to increase due to climate change. Coniferous stands planted outside the natural habitats of species belong to the most threatened forests. In this study, we assess stem circumference response of coniferous species (Larix decidua and Abies alba) to environmental conditions during the years 2015–2019. The study was performed in Arboretum in Zvolen (ca. 300 m a.s.l., Central Slovakia) characterised by a warmer and drier climate when compared to their natural habitats (located above 900 m a.s.l.), where they originated from. Seasonal radial variation, tree water deficit (ΔW), and maximum daily shrinkage (MDS) were derived from the records obtained from band dendrometers installed on five mature trees per species. Monitored species exhibited remarkably different growth patterns under highly above normal temperatures and uneven precipitation distribution. The magnitudes of reversible circumference changes (ΔW, MDS) were species-specific and strongly correlated with environmental factors. The wavelet analysis identified species-specific vulnerability to drought indicated by pronounced diurnal stem variation periodicity in rainless periods. L. decidua exhibited more strained stem water status and higher sensitivity to environmental conditions than A. alba. Tree water deficit and maximum daily shrinkage were found appropriate characteristics to compare water status of different tree species.
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35
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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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36
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Churakova Sidorova OV, Corona C, Fonti MV, Guillet S, Saurer M, Siegwolf RTW, Stoffel M, Vaganov EA. Recent atmospheric drying in Siberia is not unprecedented over the last 1,500 years. Sci Rep 2020; 10:15024. [PMID: 32929148 PMCID: PMC7490406 DOI: 10.1038/s41598-020-71656-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 08/17/2020] [Indexed: 11/26/2022] Open
Abstract
Newly developed millennial δ13C larch tree-ring chronology from Siberia allows reconstruction of summer (July) vapor pressure deficit (VPD) changes in a temperature-limited environment. VPD increased recently, but does not yet exceed the maximum values reconstructed during the Medieval Warm Anomaly. The most humid conditions in the Siberian North were recorded in the Early Medieval Period and during the Little Ice Age. Increasing VPD under elevated air temperature affects the hydrology of these sensitive ecosystems by greater evapotranspiration rates. Further VPD increases will significantly affect Siberian forests most likely leading to drought and forest mortality even under additional access of thawed permafrost water. Adaptation strategies are needed for Siberian forest ecosystems to protect them in a warming world.
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Affiliation(s)
- O V Churakova Sidorova
- Siberian Federal University, Svobodny pr. 79, Krasnoyarsk, Russian Federation, 660041. .,Institute for Environmental Sciences, University of Geneva, 66 Bvd Carl Vogt, 1205, Geneva, Switzerland.
| | - C Corona
- Geolab, UMR 6042 CNRS, Université Clermont-Auvergne (UCA), 4 rue Ledru, 63057, Clermont-Ferrand, France
| | - M V Fonti
- Siberian Federal University, Svobodny pr. 79, Krasnoyarsk, Russian Federation, 660041.,Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - S Guillet
- Institute for Environmental Sciences, University of Geneva, 66 Bvd Carl Vogt, 1205, Geneva, Switzerland
| | - M Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - R T W Siegwolf
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - M Stoffel
- Institute for Environmental Sciences, University of Geneva, 66 Bvd Carl Vogt, 1205, Geneva, Switzerland.,Dendrolab.Ch, Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.,Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, 66 Bvd Carl Vogt, 1205, Geneva, Switzerland
| | - E A Vaganov
- Siberian Federal University, Svobodny pr. 79, Krasnoyarsk, Russian Federation, 660041.,V.N. Sukachev Institute of Forest SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 50/28 Akademgorodok, Krasnoyarsk, Russian Federation, 660036
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37
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Bogdziewicz M, Fernández‐Martínez M, Espelta JM, Ogaya R, Penuelas J. Is forest fecundity resistant to drought? Results from an 18-yr rainfall-reduction experiment. THE NEW PHYTOLOGIST 2020; 227:1073-1080. [PMID: 32329082 PMCID: PMC7496795 DOI: 10.1111/nph.16597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
Recruitment is a primary determinant of the long-term dynamics of plant populations in changing environments. However, little information is known about the effects of anthropogenic environmental changes on reproductive ecology of trees. We evaluated the impact of experimentally induced 18 yr of drought on reproduction of three contrasting forest trees: Quercus ilex, Phillyrea latifolia and Arbutus unedo. Rainfall reduction did not decrease tree fecundity. Drought, however, affected the allocation of resources in Q. ilex and A. unedo but not the more drought tolerant P. latifolia. Larger crop production by Q. ilex and A. unedo was associated with a stronger decrease in growth in the rainfall-reduction plots compared with the control plots, suggesting that these species were able to maintain their fecundity by shifting their allocation of resources away from growth. Our results indicated resistance to change in tree fecundity in Mediterranean-type forest subjected to an average 15% decrease in the amount of soil moisture, suggesting that these ecosystems may adapt to a progressive increase in arid conditions. However, the species-specific reductions in growth may indirectly affect future fecundity and ultimately shift community composition, even without immediate direct effects of drought on tree fecundity.
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Affiliation(s)
- Michał Bogdziewicz
- Department of Systematic ZoologyFaculty of BiologyAdam Mickiewicz University61‐614PoznańPoland
- CREAFCerdanyola delVallès08193CataloniaSpain
| | | | | | - Romà Ogaya
- CREAFCerdanyola delVallès08193CataloniaSpain
| | - Josep Penuelas
- CREAFCerdanyola delVallès08193CataloniaSpain
- Global Ecology UnitCSICCerdanyola del Vallès 08193CataloniaSpain
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38
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Grossiord C, Buckley TN, Cernusak LA, Novick KA, Poulter B, Siegwolf RTW, Sperry JS, McDowell NG. Plant responses to rising vapor pressure deficit. THE NEW PHYTOLOGIST 2020; 226:1550-1566. [PMID: 32064613 DOI: 10.1111/nph.16485] [Citation(s) in RCA: 321] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 02/04/2020] [Indexed: 05/24/2023]
Abstract
Recent decades have been characterized by increasing temperatures worldwide, resulting in an exponential climb in vapor pressure deficit (VPD). VPD has been identified as an increasingly important driver of plant functioning in terrestrial biomes and has been established as a major contributor in recent drought-induced plant mortality independent of other drivers associated with climate change. Despite this, few studies have isolated the physiological response of plant functioning to high VPD, thus limiting our understanding and ability to predict future impacts on terrestrial ecosystems. An abundance of evidence suggests that stomatal conductance declines under high VPD and transpiration increases in most species up until a given VPD threshold, leading to a cascade of subsequent impacts including reduced photosynthesis and growth, and higher risks of carbon starvation and hydraulic failure. Incorporation of photosynthetic and hydraulic traits in 'next-generation' land-surface models has the greatest potential for improved prediction of VPD responses at the plant- and global-scale, and will yield more mechanistic simulations of plant responses to a changing climate. By providing a fully integrated framework and evaluation of the impacts of high VPD on plant function, improvements in forecasting and long-term projections of climate impacts can be made.
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Affiliation(s)
- Charlotte Grossiord
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
- École Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, 1015, Lausanne, Switzerland
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, Davis, CA, 95616, USA
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4814, Australia
| | - Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Benjamin Poulter
- Biospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - Rolf T W Siegwolf
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - John S Sperry
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Nate G McDowell
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
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39
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Griebel A, Metzen D, Boer MM, Barton CVM, Renchon AA, Andrews HM, Pendall E. Using a paired tower approach and remote sensing to assess carbon sequestration and energy distribution in a heterogeneous sclerophyll forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 699:133918. [PMID: 31522048 DOI: 10.1016/j.scitotenv.2019.133918] [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: 03/01/2019] [Revised: 08/02/2019] [Accepted: 08/13/2019] [Indexed: 06/10/2023]
Abstract
The critically endangered Cumberland Plain woodland within the greater Sydney metropolitan area hosts a dwindling refuge for melaleuca trees, an integral part of Australia's native vegetation. Despite their high carbon stocks, melaleucas have not explicitly been targeted for studies assessing their carbon sequestration potential, and especially little is known about their energy cycling or their response to increasing climate stress, precluding a holistic assessment of the resilience of Australia's forests to climate change. To improve our understanding of the role of melaleuca forest responses to climate stress, we combined forest inventory and airborne LiDAR data to identify species distribution and associated variations in forest structure, and deployed flux towers in a melaleuca-dominated (AU-Mel) and in a eucalypt-dominated (AU-Cum) stand to simultaneously monitor carbon and energy fluxes under typical growing conditions, as well as during periods with high atmospheric demand and low soil water content. We discovered that the species distribution at our study site affected the vertical vegetation structure, leading to differences in canopy coverage (75% at AU-Cum vs. 84% at AU-Mel) and plant area index (2.1 m2 m-2 at AU-Cum vs. 2.6 m2 m-2 at AU-Mel) that resulted in a heterogeneous forest landscape. Furthermore, we identified that both stands had comparable net daytime carbon exchange and sensible heat flux, whereas daytime latent heat flux (115.8 W m-2 at AU-Cum vs 119.4 W m-2 at AU-Mel, respectively) was higher at the melaleuca stand, contributing to a 0.3 °C decrease in air temperature and reduced vapor pressure deficit above the melaleuca canopy. However, increased canopy conductance and higher latent heat flux during moderate VPD or when soil moisture was low indicated a lack of water preservation at the melaleuca stand, highlighting the potential for increased vulnerability of melaleucas to projected hotter and drier future climates.
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Affiliation(s)
- Anne Griebel
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia.
| | - Daniel Metzen
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia
| | - Craig V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia
| | - Alexandre A Renchon
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia
| | - Holly M Andrews
- University of California, Riverside, Department of Evolution, Ecology, and Organismal Biology, CA 92521, United States of America
| | - Elise Pendall
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2570, Australia
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40
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Steinacker C, Beierkuhnlein C, Jaeschke A. Assessing the exposure of forest habitat types to projected climate change-Implications for Bavarian protected areas. Ecol Evol 2019; 9:14417-14429. [PMID: 31938529 PMCID: PMC6953681 DOI: 10.1002/ece3.5877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/24/2019] [Accepted: 11/04/2019] [Indexed: 12/03/2022] Open
Abstract
AIM Due to their longevity and structure, forest ecosystems are particularly affected by climate change with consequences for their biodiversity, functioning, and services to mankind. In the European Union (EU), natural and seminatural forests are protected by the Habitats Directive and the Natura 2000 network. This study aimed to assess the exposure of three legally defined forest habitat types to climate change, namely (a) Tilio-Acerion forests of slopes, screes, and ravines (9180*), (b) bog woodlands (91D0*), and (c) alluvial forests with Alnus glutinosa and Fraxinus excelsior (91E0*). We analyzed possible changes in their Bavarian distribution, including their potential future coverage by Natura 2000 sites. We hypothesized that protected areas (PAs) with larger elevational ranges will remain suitable for the forests as they allow for altitudinal distribution shifts. METHODS To estimate changes in range size and coverage by PAs, we combined correlative species distribution models (SDMs) with spatial analyses. Ensembles of SDM-algorithms were applied to two climate change scenarios (RCP4.5 and RCP8.5) of the HadGEM2-ES model for the period 2061-2080. RESULTS Our results revealed that bog woodlands experience the highest range losses (>2/3) and lowest PA coverage (max. 15% of sites with suitable conditions). Tilio-Acerion forests exhibit opposing trends depending on the scenario, while alluvial forests are less exposed to climatic changes. As expected, the impacts of climate change are more pronounced under the "business as usual" scenario (RCP8.5). Additionally, PAs in flat landscapes are more likely to lose environmental suitability for currently established forest habitat types. MAIN CONCLUSIONS Based on these findings, we advocate the expansion of the Natura 2000 network particularly in consideration of elevational gradients, connectivity, and projected climatic suitability. Nonclimatic stressors on forest ecosystems, especially bog woodlands, should be decreased and climate change mitigation efforts enhanced. We recommend transferring the approach to other habitat types and regions.
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Affiliation(s)
| | - Carl Beierkuhnlein
- Department of BiogeographyUniversity of BayreuthBayreuthGermany
- Bayreuth Center for Ecology and Environmental Research BayCEERBayreuthGermany
- Geographical Institute Bayreuth GIBBayreuthGermany
| | - Anja Jaeschke
- Department of BiogeographyUniversity of BayreuthBayreuthGermany
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41
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Salazar-Tortosa D, Castro J, Saladin B, Zimmermann NE, Rubio De Casas R. Arid environments select for larger seeds in pines (Pinus spp.). Evol Ecol 2019. [DOI: 10.1007/s10682-019-10016-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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42
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Steel EJ, Fontaine JB, Ruthrof KX, Burgess TI, Hardy GESJ. Changes in structure of over- and midstory tree species in a Mediterranean-type forest after an extreme drought-associated heatwave. AUSTRAL ECOL 2019. [DOI: 10.1111/aec.12818] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Emma J. Steel
- Environment and Conservation Science; College of Science, Health, Engineering and Education; Murdoch University; Murdoch Western Australia 6150 Australia
| | - Joseph B. Fontaine
- Environment and Conservation Science; College of Science, Health, Engineering and Education; Murdoch University; Murdoch Western Australia 6150 Australia
| | - Katinka X. Ruthrof
- Environment and Conservation Science; College of Science, Health, Engineering and Education; Murdoch University; Murdoch Western Australia 6150 Australia
- Department of Biodiversity; Conservation and Attractions; Kensington Western Australia Australia
| | - Treena I. Burgess
- Environment and Conservation Science; College of Science, Health, Engineering and Education; Murdoch University; Murdoch Western Australia 6150 Australia
| | - Giles E. St. J. Hardy
- Environment and Conservation Science; College of Science, Health, Engineering and Education; Murdoch University; Murdoch Western Australia 6150 Australia
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43
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Johnston AN, Bruggeman JE, Beers AT, Beever EA, Christophersen RG, Ransom JI. Ecological consequences of anomalies in atmospheric moisture and snowpack. Ecology 2019; 100:e02638. [PMID: 30710338 DOI: 10.1002/ecy.2638] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 09/18/2018] [Accepted: 12/03/2018] [Indexed: 11/09/2022]
Abstract
Although increased frequency of extreme-weather events is one of the most secure predictions associated with contemporary climate change, effects of such events on distribution and abundance of climate-sensitive species remain poorly understood. Montane ecosystems may be especially sensitive to extreme weather because of complex abiotic and biotic interactions that propagate from climate-driven reductions in snowpack. Snowpack not only protects subnivean biotas from extreme cold, but also influences forage availability through timing of melt-off and water availability. We related relative abundances of an alpine mammal, the American pika (Ochotona princeps), to measures of weather and snowpack dynamics over an 8-yr period that included before and after a year of record-low snowpack in Washington, USA. We sought to (1) quantify any change in pika abundance associated with the snowpack anomaly and (2) identify aspects of weather and snowpack that influenced abundance of pikas. Pikas showed a 1-yr lag response to the snowpack anomaly and exhibited marked declines in abundance at elevations below 1,400 m simultaneous with increased abundances at higher elevations. Atmospheric moisture, indexed by vapor pressure deficit (VPD), was especially important, evidenced by strong support for the top-ranked model that included the interaction of VPD with snowpack duration. Notably, our novel application of VPD from gridded climate data for analyses of animal abundances shows strong potential for improving species distribution models because VPD represents an important aspect of weather that influences the physiology and habitat of biota. Pikas were apparently affected by cold stress without snowpack at mid elevations, whereas changes to forage associated with snowpack and VPD were influential at high and low elevations. Our results reveal context dependency in pika responses to weather and illustrate how snow drought can lead to rapid change in the abundance of subnivean animals.
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Affiliation(s)
- Aaron N Johnston
- U.S. Geological Survey, Northern Rocky Mountain Science Center, 2327 University Way, Suite 2, Bozeman, Montana, 59715, USA.,School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Jason E Bruggeman
- Beartooth Wildlife Research, 4157 West 145th Street, Savage, Minnesota, 55378, USA.,Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, 200 Hodson Hall, 1980 Folwell Avenue, St. Paul, Minnesota, 55108, USA
| | - Aidan T Beers
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant Street, UCB 334, Boulder, Colorado, 80302, USA.,Institute of Arctic and Alpine Research, University of Colorado Boulder, UCB 450, Boulder, Colorado, 80309, USA.,Department of Wildland Resources, Utah State University, 5230 Old Main Hill, NR 206, Logan, Utah, 84322, USA
| | - Erik A Beever
- U.S. Geological Survey, Northern Rocky Mountain Science Center, 2327 University Way, Suite 2, Bozeman, Montana, 59715, USA.,Department of Ecology, Montana State University, P.O. Box 173460, Bozeman, Montana, 59717, USA
| | - Roger G Christophersen
- National Park Service, North Cascades National Park Service Complex, 810 State Route 20, Sedro Woolley, Washington, 98284, USA
| | - Jason I Ransom
- National Park Service, North Cascades National Park Service Complex, 810 State Route 20, Sedro Woolley, Washington, 98284, USA
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Hartmann H, Moura CF, Anderegg WRL, Ruehr NK, Salmon Y, Allen CD, Arndt SK, Breshears DD, Davi H, Galbraith D, Ruthrof KX, Wunder J, Adams HD, Bloemen J, Cailleret M, Cobb R, Gessler A, Grams TEE, Jansen S, Kautz M, Lloret F, O'Brien M. Research frontiers for improving our understanding of drought-induced tree and forest mortality. THE NEW PHYTOLOGIST 2018; 218:15-28. [PMID: 29488280 DOI: 10.1111/nph.15048] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 01/08/2018] [Indexed: 05/20/2023]
Abstract
Accumulating evidence highlights increased mortality risks for trees during severe drought, particularly under warmer temperatures and increasing vapour pressure deficit (VPD). Resulting forest die-off events have severe consequences for ecosystem services, biophysical and biogeochemical land-atmosphere processes. Despite advances in monitoring, modelling and experimental studies of the causes and consequences of tree death from individual tree to ecosystem and global scale, a general mechanistic understanding and realistic predictions of drought mortality under future climate conditions are still lacking. We update a global tree mortality map and present a roadmap to a more holistic understanding of forest mortality across scales. We highlight priority research frontiers that promote: (1) new avenues for research on key tree ecophysiological responses to drought; (2) scaling from the tree/plot level to the ecosystem and region; (3) improvements of mortality risk predictions based on both empirical and mechanistic insights; and (4) a global monitoring network of forest mortality. In light of recent and anticipated large forest die-off events such a research agenda is timely and needed to achieve scientific understanding for realistic predictions of drought-induced tree mortality. The implementation of a sustainable network will require support by stakeholders and political authorities at the international level.
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Affiliation(s)
- Henrik Hartmann
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
| | - Catarina F Moura
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
- Faculty of Sciences and Technology, NOVA University of Lisbon, Campus da Caparica, 2829-516, Caparica, Portugal
- Centre for Functional Ecology, Department of Life Sciences, Universilty of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | | | - Nadine K Ruehr
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstr. 19, 82467, Garmisch-Partenkirchen, Germany
| | - Yann Salmon
- School of Geosciences, University of Edinburgh, Crew Building, The Kings Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, 00014, Helsinki, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, 00014, Helsinki, Finland
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Centre, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, 3121, Vic., Australia
| | - David D Breshears
- School of Natural Resources and the Environment and Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Hendrik Davi
- INRA, URFM Ecologie des Forest Méditerranéennes, Domaine Saint Paul, Site Agroparc, 84914, Avignon Cedex 9, France
| | - David Galbraith
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Katinka X Ruthrof
- School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Botanic Gardens and Parks Authority, Fraser Avenue, Kings Park, WA, 6005, Australia
| | - Jan Wunder
- Insubric Ecosystems Research Group, Community Ecology, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, a Ramèl 18, CH-6593, Cadenazzo, Switzerland
- Tree-Ring Laboratory, School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Henry D Adams
- Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jasper Bloemen
- Institute of Ecology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
- Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium
| | - Maxime Cailleret
- Forest Ecology, Department of Environmental Sciences, ETH Zürich. ETH-Zentrum, CHN G77, Universitätstrasse 16, CH-8092, Zürich, Switzerland
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Richard Cobb
- Department of Natural Resources and Environmental Science, California Polytechnic State University, San Luis Obispo, CA, 93407, USA
| | - Arthur Gessler
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Thorsten E E Grams
- Ecophysiology of Plants, Technical University of Munich, Von-Carlowitz-Platz 2, 85354, Freising, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Markus Kautz
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstr. 19, 82467, Garmisch-Partenkirchen, Germany
| | - Francisco Lloret
- CREAF - Centre for Ecological Research and Applied Forestry, Cerdanyola del Vallès, Barcelona, Spain
- Unitat d'Ecologia, Department of Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma Barcelona, Edifici C, Campus UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Michael O'Brien
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Carretera de Sacramento s/n, E-04120 La Cañada, Almería, Spain
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45
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Santos CMD, Endres L, Ferreira VM, Silva JV, Rolim EV, Wanderley HCL. Photosynthetic capacity and water use efficiency in Ricinus communis (L.) under drought stress in semi-humid and semi-arid areas. AN ACAD BRAS CIENC 2017; 89:3015-3029. [PMID: 29236872 DOI: 10.1590/0001-3765201720160729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 07/28/2017] [Indexed: 01/17/2023] Open
Abstract
Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.
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Affiliation(s)
- Claudiana M Dos Santos
- Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil
| | - Laurício Endres
- Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil
| | - Vilma M Ferreira
- Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil
| | - José V Silva
- Laboratório de Fisiologia Vegetal, Universidade Federal de Alagoas, Campus Arapiraca, Av. Manoel Severino Barbosa, s/n, Bom Sucesso, 57309-005 Arapiraca, AL, Brazil
| | - Eduardo V Rolim
- Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil
| | - Humberto C L Wanderley
- Laboratório de Fisiologia Vegetal, Centro de Ciências Agrárias, Universidade Federal de Alagoas, Campus Delza Gitaí, BR 104 Norte, Km 85, 57072-900 Rio Largo, AL, Brazil
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46
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Species, Climate and Landscape Physiography Drive Variable Growth Trends in Subalpine Forests. Ecosystems 2017. [DOI: 10.1007/s10021-017-0139-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Rigden AJ, Salvucci GD. Stomatal response to humidity and CO 2 implicated in recent decline in US evaporation. GLOBAL CHANGE BIOLOGY 2017; 23:1140-1151. [PMID: 27435666 DOI: 10.1111/gcb.13439] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Evapotranspiration, defined as the total flux of water from the land surface to the atmosphere, is a major component of the hydrologic cycle and surface energy balance. Although evapotranspiration is expected to intensify with increasing temperatures, long-term, regional trends in evapotranspiration remain uncertain due to spatially and temporally limited direct measurements. In this study, we utilize an emergent relation between the land surface and atmospheric boundary layer to infer daily evapotranspiration from historical meteorological data collected at 236 weather stations across the United States. Our results suggest a statistically significant (α = 0.05) decrease in evapotranspiration of approximately 6% from 1961 to 2014, with a significant (α = 0.05) sharp decline of 13% from 1998 to 2014. We attribute the decrease in evapotranspiration mostly to declines in surface conductance, but also to offsetting changes in longwave radiation, wind speed, and incoming solar radiation. Using an established stomatal conductance model, we explain the changes in inferred surface conductance as a response to increases in carbon dioxide and, more recently, to an abrupt decrease in atmospheric humidity.
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Affiliation(s)
- Angela J Rigden
- Department of Earth and Environment, Boston University, 675 Commonwealth Ave., Boston, MA, 02215, USA
| | - Guido D Salvucci
- Department of Earth and Environment, Boston University, 675 Commonwealth Ave., Boston, MA, 02215, USA
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48
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Response of Mid-Rotation Loblolly Pine (Pinus taeda L.) Physiology and Productivity to Sustained, Moderate Drought on the Western Edge of the Range. FORESTS 2016. [DOI: 10.3390/f7090203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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49
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Breshears DD, Knapp AK, Law DJ, Smith MD, Twidwell D, Wonkka CL. Rangeland Responses to Predicted Increases in Drought Extremity. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.rala.2016.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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50
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Barnes ML, Moran MS, Scott RL, Kolb TE, Ponce‐Campos GE, Moore DJP, Ross MA, Mitra B, Dore S. Vegetation productivity responds to sub‐annual climate conditions across semiarid biomes. Ecosphere 2016. [DOI: 10.1002/ecs2.1339] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Mallory L. Barnes
- School of Natural Resources and the Environment University of Arizona TucsonArizona 85719 USA
| | - M. Susan Moran
- United States Department of Agriculture, Agricultural Research Service Southwest Watershed Research Center TucsonArizona 85719 USA
| | - Russell L. Scott
- United States Department of Agriculture, Agricultural Research Service Southwest Watershed Research Center TucsonArizona 85719 USA
| | - Thomas E. Kolb
- School of Forestry Northern Arizona University FlagstaffArizona 86001 USA
| | - Guillermo E. Ponce‐Campos
- United States Department of Agriculture, Agricultural Research Service Southwest Watershed Research Center TucsonArizona 85719 USA
| | - David J. P. Moore
- School of Natural Resources and the Environment University of Arizona TucsonArizona 85719 USA
| | - Morgan A. Ross
- School of Natural Resources and the Environment University of Arizona TucsonArizona 85719 USA
| | - Bhaskar Mitra
- School of Natural Resources and the Environment University of Arizona TucsonArizona 85719 USA
| | - Sabina Dore
- School of Forestry Northern Arizona University FlagstaffArizona 86001 USA
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