1
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Cabon A, DeRose RJ, Shaw JD, Anderegg WRL. Declining tree growth resilience mediates subsequent forest mortality in the US Mountain West. GLOBAL CHANGE BIOLOGY 2023; 29:4826-4841. [PMID: 37344959 DOI: 10.1111/gcb.16826] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/17/2023] [Accepted: 05/23/2023] [Indexed: 06/23/2023]
Abstract
Climate change-triggered forest die-off is an increasing threat to global forests and carbon sequestration but remains extremely challenging to predict. Tree growth resilience metrics have been proposed as measurable proxies of tree susceptibility to mortality. However, it remains unclear whether tree growth resilience can improve predictions of stand-level mortality. Here, we use an extensive tree-ring dataset collected at ~3000 permanent forest inventory plots, spanning 13 dominant species across the US Mountain West, where forests have experienced strong drought and extensive die-off has been observed in the past two decades, to test the hypothesis that tree growth resilience to drought can explain and improve predictions of observed stand-level mortality. We found substantial increases in growth variability and temporal autocorrelation as well declining drought resistance and resilience for a number of species over the second half of the 20th century. Declining resilience and low tree growth were strongly associated with cross- and within-species patterns of mortality. Resilience metrics had similar explicative power compared to climate and stand structure, but the covariance structure among predictors implied that the effect of tree resilience on mortality could partially be explained by stand and climate variables. We conclude that tree growth resilience offers highly valuable insights on tree physiology by integrating the effect of stressors on forest mortality but may have only moderate potential to improve large-scale projections of forest die-off under climate change.
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Affiliation(s)
- Antoine Cabon
- Wilkes Center for Climate Science and Policy, University of Utah, Salt Lake City, Utah, USA
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - R Justin DeRose
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, Utah, USA
| | - John D Shaw
- USDA Forest Service, Rocky Mountain Research Station, Logan, Utah, USA
| | - William R L Anderegg
- Wilkes Center for Climate Science and Policy, University of Utah, Salt Lake City, Utah, USA
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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2
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Li X, Ryu Y, Xiao J, Dechant B, Liu J, Li B, Jeong S, Gentine P. New-generation geostationary satellite reveals widespread midday depression in dryland photosynthesis during 2020 western U.S. heatwave. SCIENCE ADVANCES 2023; 9:eadi0775. [PMID: 37531429 PMCID: PMC10396307 DOI: 10.1126/sciadv.adi0775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/29/2023] [Indexed: 08/04/2023]
Abstract
Emerging new-generation geostationary satellites have broadened the scope for studying the diurnal cycle of ecosystem functions. We exploit observations from the Geostationary Operational Environmental Satellite-R series to examine the effect of a severe U.S. heatwave in 2020 on the diurnal variations of ecosystem photosynthesis. We find divergent responses of photosynthesis to the heatwave across vegetation types and aridity gradients, with drylands exhibiting widespread midday and afternoon depression in photosynthesis. The diurnal centroid and peak time of dryland gross primary production (GPP) substantially shift toward earlier morning times, reflecting notable water and heat stress. Our geostationary satellite-based method outperforms traditional radiation-based upscaling methods from polar-orbiting satellite snapshots in estimating daily GPP and GPP loss during heatwaves. These findings underscore the potential of geostationary satellites for diurnal photosynthesis monitoring and highlight the necessity to consider the increased diurnal asymmetry in GPP under stress when evaluating carbon-climate interactions.
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Affiliation(s)
- Xing Li
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Youngryel Ryu
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
- Department of Landscape Architecture and Rural Systems Engineering, College of Agriculture and Life Sciences, Seoul National University, South Korea
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - Benjamin Dechant
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Leipzig University, Leipzig, Germany
| | - Jiangong Liu
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Bolun Li
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Sungchan Jeong
- Department of Landscape Architecture and Rural Systems Engineering, College of Agriculture and Life Sciences, Seoul National University, South Korea
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA
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3
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Noel AR, Shriver RK, Crausbay SD, Bradford JB. Where can managers effectively resist climate-driven ecological transformation in pinyon-juniper woodlands of the US Southwest? GLOBAL CHANGE BIOLOGY 2023; 29:4327-4341. [PMID: 37246831 DOI: 10.1111/gcb.16756] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/30/2023]
Abstract
Pinyon-juniper (PJ) woodlands are an important component of dryland ecosystems across the US West and are potentially susceptible to ecological transformation. However, predicting woodland futures is complicated by species-specific strategies for persisting and reproducing under drought conditions, uncertainty in future climate, and limitations to inferring demographic rates from forest inventory data. Here, we leverage new demographic models to quantify how climate change is expected to alter population demographics in five PJ tree species in the US West and place our results in the context of a climate adaptation framework to resist, accept, or direct ecological transformation. Two of five study species, Pinus edulis and Juniperus monosperma, are projected to experience population declines, driven by both rising mortality and decreasing recruitment rates. These declines are reasonably consistent across various climate futures, and the magnitude of uncertainty in population growth due to future climate is less than uncertainty due to how demographic rates will respond to changing climate. We assess the effectiveness of management to reduce tree density and mitigate competition, and use the results to classify southwest woodlands into areas where transformation is (a) unlikely and can be passively resisted, (b) likely but may be resisted by active management, and (c) likely unavoidable, requiring managers to accept or direct the trajectory. Population declines are projected to promote ecological transformation in the warmer and drier PJ communities of the southwest, encompassing 37.1%-81.1% of our sites, depending on future climate scenarios. Less than 20% of sites expected to transform away from PJ have potential to retain existing tree composition by density reduction. Our results inform where this adaptation strategy could successfully resist ecological transformation in coming decades and allow for a portfolio design approach across the geographic range of PJ woodlands.
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Affiliation(s)
- Adam R Noel
- US Geological Survey, Southwest Biological Science Center, Flagstaff, Arizona, USA
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
| | - Robert K Shriver
- Department of Natural Resources and Environmental Sciences, University of Nevada-Reno, Reno, Nevada, USA
| | | | - John B Bradford
- US Geological Survey, Southwest Biological Science Center, Flagstaff, Arizona, USA
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
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4
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Thomas KA, Stauffer BA, Jarchow CJ. Decoupling of species and plant communities of the U.S. Southwest: A
CCSM4
climate scenario example. Ecosphere 2023. [DOI: 10.1002/ecs2.4414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Affiliation(s)
- Kathryn A. Thomas
- U.S. Geological Survey, Southwest Biological Science Center Tucson Arizona USA
| | - Brett A. Stauffer
- U.S. Geological Survey, Southwest Biological Science Center Tucson Arizona USA
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5
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Liu Y, Erbilgin N, Ratcliffe B, Klutsch JG, Wei X, Ullah A, Cappa EP, Chen C, Thomas BR, El-Kassaby YA. Pest defences under weak selection exert a limited influence on the evolution of height growth and drought avoidance in marginal pine populations. Proc Biol Sci 2022; 289:20221034. [PMID: 36069017 PMCID: PMC9449467 DOI: 10.1098/rspb.2022.1034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
While droughts, intensified by climate change, have been affecting forests worldwide, pest epidemics are a major source of uncertainty for assessing drought impacts on forest trees. Thus far, little information has documented the adaptability and evolvability of traits related to drought and pests simultaneously. We conducted common-garden experiments to investigate how several phenotypic traits (i.e. height growth, drought avoidance based on water-use efficiency inferred from δ13C and pest resistance based on defence traits) interact in five mature lodgepole pine populations established in four progeny trials in western Canada. The relevance of interpopulation variation in climate sensitivity highlighted that seed-source warm populations had greater adaptive capability than cold populations. In test sites, warming generated taller trees with higher δ13C and increased the evolutionary potential of height growth and δ13C across populations. We found, however, no pronounced gradient in defences and their evolutionary potential along populations or test sites. Response to selection was weak in defences across test sites, but high for height growth particularly at warm test sites. Response to the selection of δ13C varied depending on its selective strength relative to height growth. We conclude that warming could promote the adaptability and evolvability of growth response and drought avoidance with a limited evolutionary influence from pest (biotic) pressures.
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Affiliation(s)
- Yang Liu
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada.,McDonald Institute for Archaeological Research, University of Cambridge, Downing Street, Cambridge CB2 3DZ, UK.,Wolfson College, University of Cambridge, Barton Road, Cambridge CB3 9BB, UK
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
| | - Blaise Ratcliffe
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
| | - Xiaojing Wei
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
| | - Aziz Ullah
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
| | - Eduardo Pablo Cappa
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Recursos Biológicos, Centro de Investigación en Recursos Naturales, De Los Reseros y Doctor Nicolás Repetto s/n, 1686, Hurlingham, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Charles Chen
- Department of Biochemistry and Molecular Biology, 246 Noble Research Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Barb R Thomas
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
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6
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Anderegg WRL, Wu C, Acil N, Carvalhais N, Pugh TAM, Sadler JP, Seidl R. A climate risk analysis of Earth's forests in the 21st century. Science 2022; 377:1099-1103. [PMID: 36048937 DOI: 10.1126/science.abp9723] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Earth's forests harbor extensive biodiversity and are currently a major carbon sink. Forest conservation and restoration can help mitigate climate change; however, climate change could fundamentally imperil forests in many regions and undermine their ability to provide such mitigation. The extent of climate risks facing forests has not been synthesized globally nor have different approaches to quantifying forest climate risks been systematically compared. We combine outputs from multiple mechanistic and empirical approaches to modeling carbon, biodiversity, and disturbance risks to conduct a synthetic climate risk analysis for Earth's forests in the 21st century. Despite large uncertainty in most regions we find that some forests are consistently at higher risk, including southern boreal forests and those in western North America and parts of the Amazon.
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Affiliation(s)
- William R L Anderegg
- Wilkes Center for Climate Science and Policy, University of Utah, Salt Lake City, UT 84103 USA.,School of Biological Sciences, University of Utah, Salt Lake City, UT 84103 USA
| | - Chao Wu
- Wilkes Center for Climate Science and Policy, University of Utah, Salt Lake City, UT 84103 USA.,School of Biological Sciences, University of Utah, Salt Lake City, UT 84103 USA
| | - Nezha Acil
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.,Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Nuno Carvalhais
- Max Planck Institute for Biogeochemistry, Jena, Germany.,Departamento de Ciências e Engenharia do Ambiente, DCEA, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Thomas A M Pugh
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.,Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK.,Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Jon P Sadler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.,Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Rupert Seidl
- School of Life Sciences, Technical University of Munich, Freising, Germany.,Berchtesgaden National Park, Berchtesgaden, Germany
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7
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Jules ES, DeSiervo MH, Reilly MJ, Bost DS, Butz RJ. The effects of a half century of warming and fire exclusion on montane forests of the Klamath Mountains, California,
USA. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Erik S. Jules
- Department of Biological Sciences Humboldt State University Arcata California USA
| | | | - Matthew J. Reilly
- USDA Forest Service Pacific Northwest Research Station, Western Wildlands Environmental Threat Assessment Center, Corvallis Oregon USA
| | - Drew S. Bost
- Department of Biological Sciences Humboldt State University Arcata California USA
| | - Ramona J. Butz
- USDA Forest Service Pacific Southwest Region 1330, Bayshore Way Eureka CA USA
- Department of Forestry and Wildland Resources Humboldt State University Arcata California USA
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8
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Liu H, Xu C, Allen CD, Hartmann H, Wei X, Yakir D, Wu X, Yu P. Nature-based framework for sustainable afforestation in global drylands under changing climate. GLOBAL CHANGE BIOLOGY 2022; 28:2202-2220. [PMID: 34953175 DOI: 10.1111/gcb.16059] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 12/01/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Drylands cover more than 40% of Earth's land surface and occur at the margin of forest distributions due to the limited availability of water for tree growth. Recent elevated temperature and low precipitation have driven greater forest declines and pulses of tree mortality on dryland sites compared to humid sites, particularly in temperate Eurasia and North America. Afforestation of dryland areas has been widely implemented and is expected to increase in many drylands globally to enhance carbon sequestration and benefits to the human environment, but the interplay of sometimes conflicting afforestation outcomes has not been formally evaluated yet. Most previous studies point to conflicts between additional forest area and water consumption, in particular water yield and soil conservation/desalinization in drylands, but were generally confined to local and regional scales. Our global synthesis demonstrates that additional tree cover can amplify water consumption through a nonlinear increase in evapotranspiration-depending on tree species, age, and structure-which will be further intensified by future climate change. In this review we identify substantial knowledge gaps in addressing the dryland afforestation dilemma, where there are trade-offs with planted forests between increased availability of some resources and benefits to human habitats versus the depletion of other resources that are required for sustainable development of drylands. Here we propose a method of addressing comprehensive vegetation carrying capacity, based on regulating the distribution and structure of forest plantations to better deal with these trade-offs in forest multifunctionality. We also recommend new priority research topics for dryland afforestation, including: responses and feedbacks of dryland forests to climate change; shifts in the ratio of ecosystem ET to tree cover; assessing the role of scale of afforestation in influencing the trade-offs of dryland afforestation; and comprehensive modeling of the multifunctionality of dryland forests, including both ecophysiological and socioeconomic aspects, under a changing climate.
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Affiliation(s)
- Hongyan Liu
- College of Urban and Environmental Sciences, Sino-French Institute of Earth System Science, PKU-Saihanba Station, and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Chongyang Xu
- College of Urban and Environmental Sciences, Sino-French Institute of Earth System Science, PKU-Saihanba Station, and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Craig D Allen
- Department of Geography and Environmental Studies, University of New Mexico, Albuquerque, New Mexico, USA
| | - Henrik Hartmann
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Xiaohua Wei
- Department of Earth, Environmental and Geographic Sciences, University of British Columbia (Okanagan Campus), Kelowna, British Columbia, Canada
| | - Dan Yakir
- Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot, Israel
| | - Xiuchen Wu
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Pengtao Yu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Nature Conservation, Chinese Academy of Forestry, Beijing, China
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9
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Muehleisen AJ, Manzané‐Pinzón E, Engelbrecht BMJ, Jones FA, Comita LS. Do experimental drought stress and species' drought sensitivity influence herbivory in tropical tree seedlings? Biotropica 2022. [DOI: 10.1111/btp.13075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew J. Muehleisen
- Yale School of the Environment Yale University New Haven Connecticut USA
- Institute of Ecology and Evolution University of Oregon Eugene Oregon USA
| | - Eric Manzané‐Pinzón
- Departamento de Ciencias Naturales Facultad de Ciencias y Tecnología Universidad Tecnológica de Panamá Panama City Panama
| | - Bettina M. J. Engelbrecht
- Smithsonian Tropical Research Institute Balboa Panama
- Department of Plant Ecology Bayreuth Center for Ecology and Environmental Research University of Bayreuth Bayreuth Germany
| | - F. Andrew Jones
- Smithsonian Tropical Research Institute Balboa Panama
- Department of Botany and Plant Pathology Oregon State University Corvallis Oregon USA
| | - Liza S. Comita
- Yale School of the Environment Yale University New Haven Connecticut USA
- Smithsonian Tropical Research Institute Balboa Panama
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10
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Benson MC, Miniat CF, Oishi AC, Denham SO, Domec JC, Johnson DM, Missik JE, Phillips RP, Wood JD, Novick KA. The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric codominants. PLANT, CELL & ENVIRONMENT 2022; 45:329-346. [PMID: 34902165 DOI: 10.1111/pce.14244] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The coordination of plant leaf water potential (ΨL ) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. There is a general consensus that trees with vulnerable xylem more conservatively regulate ΨL than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh. and Liriodendron tulipifera L., by synthesizing 1600 ΨL observations, 122 xylem embolism curves and xylem anatomical measurements across 10 forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated ΨL less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose ΨL regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought-prone future.
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Affiliation(s)
- Michael C Benson
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Chelcy F Miniat
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Andrew C Oishi
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Sander O Denham
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, INRA UMR 1391 ISPA, Gradignan, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Justine E Missik
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Richard P Phillips
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jeffrey D Wood
- University of Missouri, School of Natural Resources, Columbia, Missouri, USA
| | - Kimberly A Novick
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
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11
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Erbilgin N, Zanganeh L, Klutsch JG, Chen SH, Zhao S, Ishangulyyeva G, Burr SJ, Gaylord M, Hofstetter R, Keefover-Ring K, Raffa KF, Kolb T. Combined drought and bark beetle attacks deplete non-structural carbohydrates and promote death of mature pine trees. PLANT, CELL & ENVIRONMENT 2021; 44:3636-3651. [PMID: 34612515 DOI: 10.1111/pce.14197] [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: 06/29/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
How carbohydrate reserves in conifers respond to drought and bark beetle attacks are poorly understood. We investigated changes in carbohydrate reserves and carbon-dependent diterpene defences in ponderosa pine trees that were experimentally subjected to two levels of drought stress (via root trenching) and two types of biotic challenge treatments (pheromone-induced bark beetle attacks or inoculations with crushed beetles that include beetle-associated fungi) for two consecutive years. Our results showed that trenching did not influence carbohydrates, whereas both biotic challenges reduced amounts of starch and sugars of trees. However, only the combined trenched-bark beetle attacked trees depleted carbohydrates and died during the first year of attacks. While live trees contained higher carbohydrates than dying trees, amounts of constitutive and induced diterpenes produced did not vary between live and beetle-attacked dying trees, respectively. Based on these results we propose that reallocation of carbohydrates to diterpenes during the early stages of beetle attacks is limited in drought-stricken trees, and that the combination of biotic and abiotic stress leads to tree death. The process of tree death is subsequently aggravated by beetle girdling of phloem, occlusion of vascular tissue by bark beetle-vectored fungi, and potential exploitation of host carbohydrates by bark beetle symbionts as nutrients.
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Affiliation(s)
- Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Leila Zanganeh
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
- Department of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
- Department of Forestry, New Mexico Highlands University, Las Vegas, New Mexico, USA
| | - Shih-Hsuan Chen
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Shiyang Zhao
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Guncha Ishangulyyeva
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Stephen J Burr
- Forest Health Protection, USDA Forest Service, Milwaukee, Wisconsin, USA
| | - Monica Gaylord
- Forest Health Protection, USDA Forest Service, Flagstaff, Arizona, USA
| | - Richard Hofstetter
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Thomas Kolb
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, USA
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12
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Schultz EL, Hülsmann L, Pillet MD, Hartig F, Breshears DD, Record S, Shaw JD, DeRose RJ, Zuidema PA, Evans MEK. Climate-driven, but dynamic and complex? A reconciliation of competing hypotheses for species' distributions. Ecol Lett 2021; 25:38-51. [PMID: 34708503 DOI: 10.1111/ele.13902] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/19/2021] [Accepted: 09/18/2021] [Indexed: 12/01/2022]
Abstract
Estimates of the percentage of species "committed to extinction" by climate change range from 15% to 37%. The question is whether factors other than climate need to be included in models predicting species' range change. We created demographic range models that include climate vs. climate-plus-competition, evaluating their influence on the geographic distribution of Pinus edulis, a pine endemic to the semiarid southwestern U.S. Analyses of data on 23,426 trees in 1941 forest inventory plots support the inclusion of competition in range models. However, climate and competition together only partially explain this species' distribution. Instead, the evidence suggests that climate affects other range-limiting processes, including landscape-scale, spatial processes such as disturbances and antagonistic biotic interactions. Complex effects of climate on species distributions-through indirect effects, interactions, and feedbacks-are likely to cause sudden changes in abundance and distribution that are not predictable from a climate-only perspective.
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Affiliation(s)
- Emily L Schultz
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
| | - Lisa Hülsmann
- Theoretical Ecology Lab, University of Regensburg, Regensburg, Germany
| | - Michiel D Pillet
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
| | - Florian Hartig
- Theoretical Ecology Lab, University of Regensburg, Regensburg, Germany
| | - David D Breshears
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Sydne Record
- Department of Biology, Bryn Mawr College, Bryn Mawr, Pennsylvania, USA
| | - John D Shaw
- USDA Forest Service, Rocky Mountain Research Station, Forest Inventory and Analysis, Ogden, Utah, USA
| | - R Justin DeRose
- Department of Wildland Resources, Utah State University, Logan, Utah, USA
| | - Pieter A Zuidema
- Forest Ecology and Forest Management group, Wageningen University and Research, Wageningen, The Netherlands
| | - Margaret E K Evans
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
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13
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Continent-wide synthesis of the long-term population dynamics of quaking aspen in the face of accelerating human impacts. Oecologia 2021; 197:25-42. [PMID: 34365517 DOI: 10.1007/s00442-021-05013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
In recent decades, climate change has disrupted forest functioning by promoting large-scale mortality events, declines in productivity and reduced regeneration. Understanding the temporal dynamics and spatial extent of these changes is critical given the essential ecosystem services provided by forests. As the most widespread tree species in North America, quaking aspen (Populus tremuloides) is well suited for studying the dynamics of tree populations during a period of unprecedented climate change. Synthesizing continent-wide data, we show that mortality rates of mature aspen stems have increased over the past two-to-three decades, while relative gains in aspen basal area have decreased during the same period. Patterns were pervasive across multiple stand size classes and composition types in western North America biomes, suggesting that trends in demographic rates were not simply a reflection of stand development and succession. Our review of the literature revealed that increased aspen mortality and reduced growth rates were most often associated with hotter, drier conditions, whereas reduced recruitment was most often associated with herbivory. Furthermore, interactions between climate and competition, as well as climate and insect herbivory, had important, context-dependent effects on mortality and growth, respectively. Our analyses of aspen across its entire geographic range indicate that this important tree species is experiencing substantial increases in mortality and decreases in population growth rates across multiple biomes. If such trends are not accompanied by increased recruitment, we expect that the reduced dominance of aspen in forests will lead to major declines in the many essential ecosystem services it provides.
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Moler ERV, Kolb T, Brady A, Palmiero BN, Wallace TR, Waring KM, Whipple AV. Plant developmental stage influences responses of Pinus strobiformis seedlings to experimental warming. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2021; 2:148-164. [PMID: 37283863 PMCID: PMC10168050 DOI: 10.1002/pei3.10055] [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: 11/02/2020] [Revised: 04/17/2021] [Accepted: 04/23/2021] [Indexed: 06/08/2023]
Abstract
Seedling emergence, survival, morphological and physiological traits, and oxidative stress resistance of southwestern white pine (Pinus strobiformis Engelm.) were studied in response to warming treatments applied during embryogenesis, germination, and early seedling growth. Daytime air temperature surrounding cones in tree canopies was warmed by +2.1°C during embryo development. Resulting seeds and seedlings were assigned to three thermal regimes in growth chambers, with each regime separated by 4°C to encompass the wide range of temperatures observed over space and time across the species' range, plus the effect of heat waves coupled with a high carbon emissions scenario of climate warming. The embryo warming treatment reduced percent seedling emergence in all germination and growth environments and reduced mortality of seedlings grown in the warmest environment. Warm thermal regimes during early seedling growth increased subsequent seedling resistance to oxidative stress and transpirational water use. Experimental warming during seed development, germination, and seedling growth affected seedling emergence and survival. Oxidative stress resistance, morphology, and water relations were affected only by warming imposed during germination and seedling growth. This work explores potential outcomes of climate warming on multiple dimensions of seedling performance and uniquely illustrates that plant responses to heat vary with plant developmental stage in addition to the magnitude of temperature change.
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Affiliation(s)
| | - Thomas Kolb
- School of ForestryNorthern Arizona UniversityFlagstaffAZUSA
| | - Anne Brady
- Department of Biological SciencesNorthern Arizona UniversityFlagstaffAZUSA
| | | | | | | | - Amy Vaughn Whipple
- Department of Biological SciencesNorthern Arizona UniversityFlagstaffAZUSA
- Center for Adaptive Western LandscapesNorthern Arizona UniversityFlagstaffAZUSA
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15
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Venturas MD, Todd HN, Trugman AT, Anderegg WRL. Understanding and predicting forest mortality in the western United States using long-term forest inventory data and modeled hydraulic damage. THE NEW PHYTOLOGIST 2021; 230:1896-1910. [PMID: 33112415 DOI: 10.1111/nph.17043] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Global warming is expected to exacerbate the duration and intensity of droughts in the western United States, which may lead to increased tree mortality. A prevailing proximal mechanism of drought-induced tree mortality is hydraulic damage, but predicting tree mortality from hydraulic theory and climate data still remains a major scientific challenge. We used forest inventory data and a plant hydraulic model (HM) to address three questions: can we capture regional patterns of drought-induced tree mortality with HM-predicted damage thresholds; do HM metrics improve predictions of mortality across broad spatial areas; and what are the dominant controls of forest mortality when considering stand characteristics, climate metrics, and simulated hydraulic stress? We found that the amount of variance explained by models predicting mortality was limited (R2 median = 0.10, R2 range: 0.00-0.52). HM outputs, including hydraulic damage and carbon assimilation diagnostics, moderately improve mortality prediction across the western US compared with models using stand and climate predictors alone. Among factors considered, metrics of stand density and tree size tended to be some of the most critical factors explaining mortality, probably highlighting the important roles of structural overshoot, stand development, and biotic agent host selection and outbreaks in mortality patterns.
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Affiliation(s)
- Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Henry N Todd
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
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16
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Reed CC, Hood SM. Few generalizable patterns of tree-level mortality during extreme drought and concurrent bark beetle outbreaks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:141306. [PMID: 32846245 DOI: 10.1016/j.scitotenv.2020.141306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/14/2020] [Accepted: 07/26/2020] [Indexed: 06/11/2023]
Abstract
Tree mortality associated with drought and concurrent bark beetle outbreaks is expected to increase with further climate change. When these two types of disturbance occur in concert it complicates our ability to accurately predict future forest mortality. The recent extreme California USA drought and bark beetle outbreaks resulted in extensive tree mortality and provides a unique opportunity to examine questions of why some trees die while others survive these co-occurring disturbances. We use plot-level data combined with a three-proxy tree-level approach using radial growth, carbon isotopes, and resin duct metrics to evaluate 1) whether variability in stand structure, tree growth or size, carbon isotope discrimination, or defenses precede mortality, 2) how relationships between these proxies differ for surviving and now-dead trees, and 3) whether generalizable risk factors for tree mortality exist across pinyon pine (Pinus monophylla), ponderosa pine (P. ponderosa), white fir (Abies concolor), and incense cedar (Calocedrus decurrens) affected by the combination of drought and beetle outbreaks. We find that risk factors associated with mortality differ between species, and that few generalizable patterns exist when bark beetle outbreaks occur in concert with a particularly long, hot drought. We see evidence that both long-term differences in physiology and shorter-term beetle-related selection and variability in defenses influence mortality susceptibility for ponderosa pine, whereas beetle dynamics may play a more prominent role in mortality patterns for white fir and pinyon pine. In contrast, incense cedar mortality appears to be attributable to long-term effects of growth suppression. Risk factors that predispose some trees to drought and beetle-related mortality likely reflect species-specific strategies for dealing with these particular disturbance types. The combined influence of beetles and drought necessitates the consideration of multiple, species-specific risk factors to more accurately model forest mortality in the face of similar extreme events more likely under future climates.
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Affiliation(s)
- Charlotte C Reed
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA.
| | - Sharon M Hood
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
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17
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Perkins-Taylor IE, Frey JK. Predicting the distribution of a rare chipmunk ( Neotamias quadrivittatus oscuraensis): comparing MaxEnt and occupancy models. J Mammal 2020; 101:1035-1048. [PMID: 33033469 PMCID: PMC7528646 DOI: 10.1093/jmammal/gyaa057] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 05/09/2020] [Indexed: 11/13/2022] Open
Abstract
Species distribution models (SDMs) use presence records to determine the relationship between species occurrence and various environmental variables to create predictive maps describing the species’ distribution. The Oscura Mountains Colorado chipmunk (Neotamias quadrivittatus oscuraensis) occurs in central New Mexico and is of conservation concern due to its relict distribution and threats to habitat. We previously created an occupancy model for this taxon, but were concerned that the model may not have adequately captured the ecological factors influencing the chipmunk’s distribution because of the data hungry nature of occupancy modeling. MaxEnt is another SDM method that is particularly effective at testing large numbers of variables and handling small sample sizes. Our goal was to create a MaxEnt model for the Oscura Mountains Colorado chipmunk and to compare it with our previous occupancy model for this taxon, either to strengthen our original assessment of the relevant ecological factors or identify additional factors that were not captured by our occupancy model. We created MaxEnt models using occurrence records from baited camera traps and opportunistic surveys. We adjusted model complexity using a novel method for tuning both the regularization multiplier and feature class parameters while also performing variable selection. We compared the distribution maps and variables selected by MaxEnt to the results of our occupancy model for this taxon. The MaxEnt and occupancy models selected similar environmental variables and the overall spatial pattern of occurrence was similar for each model. Likelihood of occurrence was positively related to elevation, piñon woodland vegetation type, and topographic variables associated with escarpments. The overall similarities between the MaxEnt and occupancy models increased our confidence of the ecological factors influencing the distribution of the chipmunk. We conclude that MaxEnt offers advantages for predicting the distribution of rare species, which can help inform conservation actions.
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Affiliation(s)
- Ian E Perkins-Taylor
- Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM, USA
| | - Jennifer K Frey
- Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM, USA
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18
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Six DL. Niche construction theory can link bark beetle-fungus symbiosis type and colonization behavior to large scale causal chain-effects. CURRENT OPINION IN INSECT SCIENCE 2020; 39:27-34. [PMID: 32114295 DOI: 10.1016/j.cois.2019.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/16/2019] [Accepted: 12/21/2019] [Indexed: 06/10/2023]
Abstract
Bark beetles form a variety of symbioses with fungi. Recent studies reveal how the fungi influence beetle nutrition and detoxify tree defenses and provide insight into why these symbioses vary so greatly in their outcomes, not only for host and symbiont, but also for the forest ecosystems within which they exist. Here, I review recent advances in our knowledge of these systems. I then introduce how niche construction theory can provide a framework to use this knowledge to better understand how different symbiosis types result in a gradient of ecosystem effects ranging from massive and durable to those of little ecological consequence.
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Affiliation(s)
- Diana L Six
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT 59804, USA.
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19
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Using Satellite Imagery to Evaluate Bark Beetle-Caused Tree Mortality Reported in Aerial Surveys in a Mixed Conifer Forest in Northern Idaho, USA. FORESTS 2020. [DOI: 10.3390/f11050529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bark beetles cause significant tree mortality in western North America. The United States Forest Service coordinates annual insect and disease surveys (IDS) by observers in airplanes to map and quantify the tree mortality caused by beetles. The subjective nature of these surveys means that accuracy evaluation is important for characterizing uncertainty. Furthermore, the metric reported for quantifying tree mortality recently changed (2012–2018 depending in region) from killed trees per acre to percent tree mortality within damage polygons, posing challenges for linking older and newer records. Here we evaluated IDS severity estimates in a beetle-affected forest in northern Idaho, USA using fine-resolution satellite imagery, which permitted greater areal coverage than field data. We first used well-established methods to map beetle-caused tree mortality in two WorldView-2 (WV2) images with a high accuracy relative to field observations. Trees-per-acre measurements within collocated IDS polygons were then converted to percent mortality using three methods and evaluated with the WV2 maps. The overall accuracies for the three methods ranged from 35–38% (for methods that used five percent-mortality classes) and 49–56% (three classes). When IDS and WV2 estimates of mortality severity that were within ±15% of each other were considered accurate, overall accuracies were 71–78%. Within the aerial survey damage polygons, the total mortality area tended to be overestimated relative to WV2. WV2 imagery identified ~50% more mortality across the study region compared with the IDS methods, with most of the difference occurring where damage was low severity or in wilderness areas. Severity of Douglas-fir beetle-caused tree mortality was estimated the most accurately, whereas severity of mountain pine beetle-caused tree mortality was estimated the least accurately. Future studies that control for temporal ambiguity between IDS and satellite imagery, as well as IDS spatial error, might provide better assessments of IDS severity accuracy. Our study increases the usefulness of the rich aerial survey database by providing estimates of uncertainty in the IDS database of tree mortality severity.
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20
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Huang J, Kautz M, Trowbridge AM, Hammerbacher A, Raffa KF, Adams HD, Goodsman DW, Xu C, Meddens AJH, Kandasamy D, Gershenzon J, Seidl R, Hartmann H. Tree defence and bark beetles in a drying world: carbon partitioning, functioning and modelling. THE NEW PHYTOLOGIST 2020; 225:26-36. [PMID: 31494935 DOI: 10.1111/nph.16173] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 08/28/2019] [Indexed: 05/14/2023]
Abstract
Drought has promoted large-scale, insect-induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under on-going climate change. Here we propose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: (1) there is a trade-off in tree carbon investment between primary and secondary metabolites (e.g. growth vs defence); (2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and (3) implementing conifer-bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large-scale vegetation models, the under-representation of insect-induced tree mortality.
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Affiliation(s)
- Jianbei Huang
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Markus Kautz
- Department of Forest Health, Forest Research Institute Baden-Württemberg, 79100, Freiburg, Germany
| | - Amy M Trowbridge
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Bozeman, MT, 59717-3120, USA
- Department of Entomology, University of Wisconsin, Madison, WI, 53706, USA
| | - Almuth Hammerbacher
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
- Department of Zoology and Entomology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, 0028, Pretoria, South Africa
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin, Madison, WI, 53706, USA
| | - Henry D Adams
- Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Devin W Goodsman
- Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada
| | - Chonggang Xu
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Arjan J H Meddens
- School of the Environment, Washington State University, Pullman, WA, 99164-2812, USA
| | | | - Jonathan Gershenzon
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
| | - Rupert Seidl
- Institute of Silviculture, Department of Forest- and Soil Sciences, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
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21
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Flake SW, Weisberg PJ. Fine-scale stand structure mediates drought-induced tree mortality in pinyon-juniper woodlands. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01831. [PMID: 30548934 DOI: 10.1002/eap.1831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/24/2018] [Accepted: 08/30/2018] [Indexed: 05/25/2023]
Abstract
Severe drought has resulted in widespread tree die-off events in forests and woodlands globally and is forecast to become more frequent in coming decades. Tree mortality is a complex process influenced by climate, soils, characteristics of individual trees, interactions between trees, and the dynamics of pests and pathogens. The role of stand structure and stand density in mediating the resistance of trees to drought remains poorly understood, especially in semiarid woodlands, which are expected to be highly susceptible to future severe drought. We sampled permanent plots in central Nevada woodlands dominated by single-leaf pinyon pine and Utah juniper before and after a severe multi-year drought (2013-2015) to investigate the importance of climate, tree attributes, and local-neighborhood stand structure on tree mortality and canopy dieback at the level of individual trees and 0.1-ha plots. We observed widespread tree mortality of pinyon at approximately eight times the reported background mortality rate, and substantial canopy dieback in both pinyon and juniper. Both species were more prone to mortality and dieback in hotter, drier sites. Canopy dieback was associated with both long-term average climate and the severity of recent drought, with elevated mortality on sites with higher water deficits, average summer temperatures, and vapor pressure deficits. Soils also played a role in tree dieback, with greater mortality on deeper soils. While mortality was driven largely by climate at coarse scales, fine-scale stand structure interacted with climate to mediate mortality and dieback. Neighborhood statistics showed that trees were susceptible to competitive influence, and pinyon trees were especially sensitive to neighborhood density on drier sites. Mortality and dieback were associated with diverse, co-occurring insect and parasitic plant mortality agents. Canopy dieback prior to the drought was strongly associated with tree mortality during the drought, implying that current widespread defoliation caused by these agents may foreshadow future elevated woodland decline. Fine-scale influences such as stand structure and soil characteristics play a key role in the long-term dynamics of semiarid woodlands, and these factors should be considered in predictive models of forest and woodland susceptibility to drought.
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Affiliation(s)
- Samuel W Flake
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada, 89557, USA
| | - Peter J Weisberg
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada, 89557, USA
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22
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Whipple AV, Cobb NS, Gehring CA, Mopper S, Flores-Rentería L, Whitham TG. Long-Term Studies Reveal Differential Responses to Climate Change for Trees Under Soil- or Herbivore-Related Stress. FRONTIERS IN PLANT SCIENCE 2019; 10:132. [PMID: 30833952 PMCID: PMC6387935 DOI: 10.3389/fpls.2019.00132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
Worldwide, trees are confronting increased temperature and aridity, exacerbating susceptibility to herbivory. Long-term studies comparing patterns of plant performance through drought can help identify variation among and within populations in vulnerability to climate change and herbivory. We use long-term monitoring data to examine our overarching hypothesis that the negative impacts of poor soil and herbivore susceptibility would be compounded by severe drought. We studied pinyon pine, Pinus edulis, a widespread southwestern tree species that has suffered extensive climate-change related mortality. We analyzed data on mortality, growth, male reproduction, and herbivory collected for 14-32 years in three areas with distinct soil-types. We used standardized precipitation-evapotranspiration index (SPEI) as a climate proxy that summarizes the impacts of drought due to precipitation and temperature variation on semi-arid forests. Several key findings emerged: (1) Plant performance measurements did not support our hypothesis that trees growing in stressful, coarse-textured soils would suffer more than trees growing in finer-textured soils. Stem growth at the area with coarse, young cinder soils (area one) responded only weakly to drought, while stem growth on more developed soils with sedimentary (area two) and volcanic (area three) substrates, was strongly negatively affected by drought. Male reproduction declined less with drought at area one and more at areas two and three. Overall mortality was 30% on coarse cinder soils (area one) and averaged 55% on finer soil types (areas two and three). (2) Although moth herbivore susceptible trees were hypothesized to suffer more with drought than moth resistant trees, the opposite occurred. Annual stem growth was negatively affected by drought for moth resistant trees, but much less strongly for moth susceptible trees. (3) In contrast to our hypothesis, moths declined with drought. Overall, chronically water-stressed and herbivore-susceptible trees had smaller declines in performance relative to less-stressed trees during drought years. These long-term findings support the idea that stressed trees might be more resistant to drought since they may have adapted or acclimated to resist drought-related mortality.
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Affiliation(s)
- Amy V. Whipple
- Department of Biological Sciences, Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, United States
| | - Neil S. Cobb
- Department of Biological Sciences, Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, United States
| | - Catherine A. Gehring
- Department of Biological Sciences, Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, United States
| | - Susan Mopper
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, United States
| | | | - Thomas G. Whitham
- Department of Biological Sciences, Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, United States
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23
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Whitebark and Foxtail Pine in Yosemite, Sequoia, and Kings Canyon National Parks: Initial Assessment of Stand Structure and Condition. FORESTS 2019. [DOI: 10.3390/f10010035] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Inventory & Monitoring Division of the U.S. National Park Service conducts long-term monitoring to provide park managers information on the status and trends in biological and environmental attributes including white pines. White pines are foundational species in many subalpine ecosystems and are currently experiencing population declines. Here we present results on the status of whitebark and foxtail pine in the southern Sierra Nevada of California, an area understudied relative to other parts of their ranges. We selected random plot locations in Yosemite, Sequoia, and Kings Canyon national parks using an equal probability spatially-balanced approach. Tree- and plot-level data were collected on forest structure, composition, demography, cone production, crown mortality, and incidence of white pine blister rust and mountain pine beetle. We measured 7899 whitebark pine, 1112 foxtail pine, and 6085 other trees from 2012–2017. All factors for both species were spatially highly variable. Whitebark pine occurred in nearly-pure krummholz stands at or near treeline and as a minor component of mixed species forests. Ovulate cones were observed on 25% of whitebark pine and 69% of foxtail pine. Whitebark pine seedlings were recorded in 58% of plots, and foxtail pine seedlings in only 21% of plots. Crown mortality (8% in whitebark, 6% in foxtail) was low and significantly higher in 2017 compared to previous years. Less than 1% of whitebark and zero foxtail pine were infected with white pine blister rust and <1% of whitebark and foxtail pine displayed symptoms of mountain pine beetle attack. High elevation white pines in the southern Sierra Nevada are healthy compared to other portions of their range where population declines are significant and well documented. However, increasing white pine blister rust and mountain pine beetle occurrence, coupled with climate change projections, portend future declines for these species, underscoring the need for broad-scale collaborative monitoring.
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24
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Perkins-Taylor IE, Frey JK. Ecological factors associated with site occupancy of an endemic chipmunk. J Wildl Manage 2018. [DOI: 10.1002/jwmg.21506] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ian E. Perkins-Taylor
- New Mexico State University; Department of Fish, Wildlife and Conservation Ecology; 2980 S Espina Street, Knox Hall 132, P.O. Box 30003, MSC 4901 Las Cruces NM 88003-8003 USA
| | - Jennifer K. Frey
- New Mexico State University; Department of Fish, Wildlife and Conservation Ecology; 2980 S Espina Street, Knox Hall 132, P.O. Box 30003, MSC 4901 Las Cruces NM 88003-8003 USA
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25
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Palmquist KA, Bradford JB, Martyn TE, Schlaepfer DR, Lauenroth WK. STEPWAT
2: an individual‐based model for exploring the impact of climate and disturbance on dryland plant communities. Ecosphere 2018. [DOI: 10.1002/ecs2.2394] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Kyle A. Palmquist
- Department of Botany University of Wyoming Laramie Wyoming 82071 USA
| | - John B. Bradford
- U.S. Geological Survey, Southwest Biological Science Center Flagstaff Arizona 86001 USA
| | - Trace E. Martyn
- School of Biological Sciences The University of Queensland St. Lucia Queensland 4072 Australia
| | - Daniel R. Schlaepfer
- School of Forestry and Environmental Studies Yale University New Haven Connecticut 06511 USA
| | - William K. Lauenroth
- Department of Botany University of Wyoming Laramie Wyoming 82071 USA
- School of Forestry and Environmental Studies Yale University New Haven Connecticut 06511 USA
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26
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Lloret F, Kitzberger T. Historical and event-based bioclimatic suitability predicts regional forest vulnerability to compound effects of severe drought and bark beetle infestation. GLOBAL CHANGE BIOLOGY 2018; 24:1952-1964. [PMID: 29316042 DOI: 10.1111/gcb.14039] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Vulnerability to climate change, and particularly to climate extreme events, is expected to vary across species ranges. Thus, we need tools to standardize the variability in regional climatic legacy and extreme climate across populations and species. Extreme climate events (e.g., droughts) can erode populations close to the limits of species' climatic tolerance. Populations in climatic-core locations may also become vulnerable because they have developed a greater demand for resources (i.e., water) that cannot be enough satisfied during the periods of scarcity. These mechanisms can become exacerbated in tree populations when combined with antagonistic biotic interactions, such as insect infestation. We used climatic suitability indices derived from Species Distribution Models (SDMs) to standardize the climatic conditions experienced across Pinus edulis populations in southwestern North America, during a historical period (1972-2000) and during an extreme event (2001-2007), when the compound effect of hot drought and bark beetle infestation caused widespread die-off and mortality. Pinus edulis climatic suitability diminished dramatically during the die-off period, with remarkable variation between years. P. edulis die-off occurred mainly not just in sites that experienced lower climatic suitability during the drought but also where climatic suitability was higher during the historical period. The combined effect of historically high climatic suitability and a marked decrease in the climatic suitability during the drought best explained the range-wide mortality. Lagged effects of climatic suitability loss in previous years and co-occurrence of Juniperus monosperma also explained P. edulis die-off in particular years. Overall, the study shows that past climatic legacy, likely determining acclimation, together with competitive interactions plays a major role in responses to extreme drought. It also provides a new approach to standardize the magnitude of climatic variability across populations using SDMs, improving our capacity to predict population's or species' vulnerability to climatic change.
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Affiliation(s)
- Francisco Lloret
- CREAF Cerdanyola del Vallès, Bellaterra, Spain
- Univ Autònoma Barcelona, Cerdanyola del Vallès, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA-CONICET, Universidad Nacional del Comahue, Bariloche, Argentina
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Jump AS, Ruiz-Benito P, Greenwood S, Allen CD, Kitzberger T, Fensham R, Martínez-Vilalta J, Lloret F. Structural overshoot of tree growth with climate variability and the global spectrum of drought-induced forest dieback. GLOBAL CHANGE BIOLOGY 2017; 23:3742-3757. [PMID: 28135022 DOI: 10.1111/gcb.13636] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/26/2016] [Indexed: 05/25/2023]
Abstract
Ongoing climate change poses significant threats to plant function and distribution. Increased temperatures and altered precipitation regimes amplify drought frequency and intensity, elevating plant stress and mortality. Large-scale forest mortality events will have far-reaching impacts on carbon and hydrological cycling, biodiversity, and ecosystem services. However, biogeographical theory and global vegetation models poorly represent recent forest die-off patterns. Furthermore, as trees are sessile and long-lived, their responses to climate extremes are substantially dependent on historical factors. We show that periods of favourable climatic and management conditions that facilitate abundant tree growth can lead to structural overshoot of aboveground tree biomass due to a subsequent temporal mismatch between water demand and availability. When environmental favourability declines, increases in water and temperature stress that are protracted, rapid, or both, drive a gradient of tree structural responses that can modify forest self-thinning relationships. Responses ranging from premature leaf senescence and partial canopy dieback to whole-tree mortality reduce canopy leaf area during the stress period and for a lagged recovery window thereafter. Such temporal mismatches of water requirements from availability can occur at local to regional scales throughout a species geographical range. As climate change projections predict large future fluctuations in both wet and dry conditions, we expect forests to become increasingly structurally mismatched to water availability and thus overbuilt during more stressful episodes. By accounting for the historical context of biomass development, our approach can explain previously problematic aspects of large-scale forest mortality, such as why it can occur throughout the range of a species and yet still be locally highly variable, and why some events seem readily attributable to an ongoing drought while others do not. This refined understanding can facilitate better projections of structural overshoot responses, enabling improved prediction of changes in forest distribution and function from regional to global scales.
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Affiliation(s)
- Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
- Forest Ecology and Restoration Group, Department of Life Sciences, Science Building, Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, 8400, Río Negro, Argentina
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia
- School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Jordi Martínez-Vilalta
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
- Autonomous University of Barcelona, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Francisco Lloret
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
- Autonomous University of Barcelona, Cerdanyola del Vallès 08193, Catalonia, Spain
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28
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Petit G, Savi T, Consolini M, Anfodillo T, Nardini A. Interplay of growth rate and xylem plasticity for optimal coordination of carbon and hydraulic economies in Fraxinus ornus trees. TREE PHYSIOLOGY 2016; 36:1310-1319. [PMID: 27587483 DOI: 10.1093/treephys/tpw069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/17/2016] [Accepted: 07/02/2016] [Indexed: 05/22/2023]
Abstract
Efficient leaf water supply is fundamental for assimilation processes and tree growth. Renovating the architecture of the xylem transport system requires an increasing carbon investment while growing taller, and any deficiency of carbon availability may result in increasing hydraulic constraints to water flow. Therefore, plants need to coordinate carbon assimilation and biomass allocation to guarantee an efficient and safe long-distance transport system. We tested the hypothesis that reduced branch elongation rates together with carbon-saving adjustments of xylem anatomy hydraulically compensate for the reduction in biomass allocation to xylem. We measured leaf biomass, hydraulic and anatomical properties of wood segments along the main axis of branches in 10 slow growing (SG) and 10 fast growing (FG) Fraxinus ornus L. trees. Branches of SG trees had five times slower branch elongation rate (7 vs 35 cm year-1), and produced a higher leaf biomass (P < 0.0001) and thinner xylem rings with fewer but larger vessels (P < 0.0001). On the contrary, we found no differences between SG and FG trees in terms of leaf-specific conductivity (P > 0.05) and xylem safety (Ψ50 ≈ -3.2 MPa). Slower elongation rate coupled with thinner annual rings and larger vessels allows the reduction of carbon costs associated with growth, while maintaining similar leaf-specific conductivity and xylem safety.
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Affiliation(s)
- Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Martina Consolini
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
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29
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Overstory Tree Mortality in Ponderosa Pine and Spruce-Fir Ecosystems Following a Drought in Northern New Mexico. FORESTS 2016. [DOI: 10.3390/f7100225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Venturas MD, MacKinnon ED, Dario HL, Jacobsen AL, Pratt RB, Davis SD. Chaparral Shrub Hydraulic Traits, Size, and Life History Types Relate to Species Mortality during California's Historic Drought of 2014. PLoS One 2016; 11:e0159145. [PMID: 27391489 PMCID: PMC4938587 DOI: 10.1371/journal.pone.0159145] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/28/2016] [Indexed: 11/21/2022] Open
Abstract
Chaparral is the most abundant vegetation type in California and current climate change models predict more frequent and severe droughts that could impact plant community structure. Understanding the factors related to species-specific drought mortality is essential to predict such changes. We predicted that life history type, hydraulic traits, and plant size would be related to the ability of species to survive drought. We evaluated the impact of these factors in a mature chaparral stand during the drought of 2014, which has been reported as the most severe in California in the last 1,200 years. We measured tissue water potential, native xylem specific conductivity, leaf specific conductivity, percentage loss in conductivity, and chlorophyll fluorescence for 11 species in February 2014, which was exceptionally dry following protracted drought. Mortality among the 11 dominant species ranged from 0 to 93%. Total stand density was reduced 63.4% and relative dominance of species shifted after the drought. Mortality was negatively correlated with water potential, native xylem specific conductivity, and chlorophyll fluorescence, but not with percent loss in hydraulic conductivity and leaf specific conductivity. The model that best explained mortality included species and plant size as main factors and indicated that larger plants had greater survival for 2 of the species. In general, species with greater resistance to water-stress induced cavitation showed greater mortality levels. Despite adult resprouters typically being more vulnerable to cavitation, results suggest that their more extensive root systems enable them to better access soil moisture and avoid harmful levels of dehydration. These results are consistent with the hypothesis that short-term high intensity droughts have the strongest effect on mature plants of shallow-rooted dehydration tolerant species, whereas deep-rooted dehydration avoiding species fare better in the short-term. Severe droughts can drive changes in chaparral structure as a result of the differential mortality among species.
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Affiliation(s)
- Martin D. Venturas
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA 93311, United States of America
- Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid, Avda. de las Moreras s/n, 28040, Madrid, Spain
- * E-mail:
| | - Evan D. MacKinnon
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA 93311, United States of America
| | - Hannah L. Dario
- Natural Science Division, Pepperdine University, 24255 Pacific Coast Highway, Malibu, CA 90263, United States of America
| | - Anna L. Jacobsen
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA 93311, United States of America
| | - R. Brandon Pratt
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA 93311, United States of America
| | - Stephen D. Davis
- Natural Science Division, Pepperdine University, 24255 Pacific Coast Highway, Malibu, CA 90263, United States of America
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Littell JS, Peterson DL, Riley KL, Liu Y, Luce CH. A review of the relationships between drought and forest fire in the United States. GLOBAL CHANGE BIOLOGY 2016; 22:2353-69. [PMID: 27090489 DOI: 10.1111/gcb.13275] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 01/29/2016] [Accepted: 02/06/2016] [Indexed: 05/22/2023]
Abstract
The historical and presettlement relationships between drought and wildfire are well documented in North America, with forest fire occurrence and area clearly increasing in response to drought. There is also evidence that drought interacts with other controls (forest productivity, topography, fire weather, management activities) to affect fire intensity, severity, extent, and frequency. Fire regime characteristics arise across many individual fires at a variety of spatial and temporal scales, so both weather and climate - including short- and long-term droughts - are important and influence several, but not all, aspects of fire regimes. We review relationships between drought and fire regimes in United States forests, fire-related drought metrics and expected changes in fire risk, and implications for fire management under climate change. Collectively, this points to a conceptual model of fire on real landscapes: fire regimes, and how they change through time, are products of fuels and how other factors affect their availability (abundance, arrangement, continuity) and flammability (moisture, chemical composition). Climate, management, and land use all affect availability, flammability, and probability of ignition differently in different parts of North America. From a fire ecology perspective, the concept of drought varies with scale, application, scientific or management objective, and ecosystem.
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Affiliation(s)
- Jeremy S Littell
- DOI Alaska Climate Science Center, 4210 University Drive, Anchorage, AK, 99508, USA
| | - David L Peterson
- USDA Forest Service Pacific Northwest Research Station, 400 N. 34th Street, Suite 201, Seattle, WA, 98103, USA
| | - Karin L Riley
- USDA Forest Service Rocky Mountain Research Station, 800 East Beckwith, Missoula, MT, 59801, USA
| | - Yongquiang Liu
- USDA Forest Service Southern Research Station, 320 Green Street, Athens, GA, 30602, USA
| | - Charles H Luce
- USDA Forest Service Rocky Mountain Research Station, 322 East Front Street, Suite 401, Boise, ID, 83702, USA
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32
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Baer A, Wheeler JK, Pittermann J. Not dead yet: the seasonal water relations of two perennial ferns during California's exceptional drought. THE NEW PHYTOLOGIST 2016; 210:122-132. [PMID: 26660879 DOI: 10.1111/nph.13770] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/17/2015] [Indexed: 06/05/2023]
Abstract
The understory of the redwood forests of California's coast harbors perennial ferns, including Polystichum munitum and Dryopteris arguta. Unusual for ferns, these species are adapted to the characteristic Mediterranean-type dry season, but the mechanisms of tolerance have not been studied. The water relations of P. munitum and D. arguta were surveyed for over a year, including measures of water potential (Ψ), stomatal conductance (gs) and frond stipe hydraulic conductivity (K). A dehydration and re-watering experiment on potted P. munitum plants corroborated the field data. The seasonal Ψ varied from 0 to below -3 MPa in both species, with gs and K generally tracking Ψ; the loss of K rarely exceeded 80%. Quantile regression analysis showed that, at the 0.1 quantile, 50% of K was lost at -2.58 and -3.84 MPa in P. munitum and D. arguta, respectively. The hydraulic recovery of re-watered plants was attributed to capillarity. The seasonal water relations of P. munitum and D. arguta are variable, but consistent with laboratory-based estimates of drought tolerance. Hydraulic and Ψ recovery following rain allows perennial ferns to survive severe drought, but prolonged water deficit, coupled with insect damage, may hamper frond survival. The legacy effects of drought on reproductive capacity and community dynamics are unknown.
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Affiliation(s)
- Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | - James K Wheeler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
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33
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Anderegg WRL, Hicke JA, Fisher RA, Allen CD, Aukema J, Bentz B, Hood S, Lichstein JW, Macalady AK, McDowell N, Pan Y, Raffa K, Sala A, Shaw JD, Stephenson NL, Tague C, Zeppel M. Tree mortality from drought, insects, and their interactions in a changing climate. THE NEW PHYTOLOGIST 2015; 208:674-83. [PMID: 26058406 DOI: 10.1111/nph.13477] [Citation(s) in RCA: 277] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/23/2015] [Indexed: 05/20/2023]
Abstract
Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects - bark beetles and defoliators - which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree-insect interactions will better inform projections of forest ecosystem responses to climate change.
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Affiliation(s)
- William R L Anderegg
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08540, USA
| | - Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, ID, 83844, USA
| | - Rosie A Fisher
- National Center for Atmospheric Research, Boulder, CO, 80305, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, Jemez Mountains Field Station, Los Alamos, NM, 87544, USA
| | - Juliann Aukema
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, 93117, USA
| | - Barbara Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, UT, 84321, USA
| | - Sharon Hood
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - Jeremy W Lichstein
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Alison K Macalady
- School of Geography and Development, University of Arizona, Tucson, AZ, 85712, USA
| | - Nate McDowell
- Earth and Environmental Sciences Division, Los Alamos National Lab, Los Alamos, NM, 87545, USA
| | - Yude Pan
- Northern Research Station, US Forest Service, Newtown Square, PA, 19073, USA
| | - Kenneth Raffa
- Department of Entomology, University of Wisconsin, Madison, WI, 53706, USA
| | - Anna Sala
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - John D Shaw
- Rocky Mountain Research Station, US Forest Service, Ogden, UT, 84401, USA
| | - Nathan L Stephenson
- US Geological Survey, Western Ecological Research Center, 47050 Generals Highway No. 4, Three Rivers, CA, 93271, USA
| | - Christina Tague
- Bren School of Environmental Science and Management, University of California - Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Melanie Zeppel
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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34
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Gaylord ML, Kolb TE, McDowell NG. Mechanisms of piñon pine mortality after severe drought: a retrospective study of mature trees. TREE PHYSIOLOGY 2015; 35:806-816. [PMID: 26048753 DOI: 10.1093/treephys/tpv038] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
Conifers have incurred high mortality during recent global-change-type drought(s) in the western USA. Mechanisms of drought-related tree mortality need to be resolved to support predictions of the impacts of future increases in aridity on vegetation. Hydraulic failure, carbon starvation and lethal biotic agents are three potentially interrelated mechanisms of tree mortality during drought. Our study compared a suite of measurements related to these mechanisms between 49 mature piñon pine (Pinus edulis Engelm.) trees that survived severe drought in 2002 (live trees) and 49 trees that died during the drought (dead trees) over three sites in Arizona and New Mexico. Results were consistent over all sites indicating common mortality mechanisms over a wide region rather than site-specific mechanisms. We found evidence for an interactive role of hydraulic failure, carbon starvation and biotic agents in tree death. For the decade prior to the mortality event, dead trees had twofold greater sapwood cavitation based on frequency of aspirated tracheid pits observed with scanning electron microscopy (SEM), smaller inter-tracheid pit diameter measured by SEM, greater diffusional constraints to photosynthesis based on higher wood δ(13)C, smaller xylem resin ducts, lower radial growth and more bark beetle (Coleoptera: Curculionidae) attacks than live trees. Results suggest that sapwood cavitation, low carbon assimilation and low resin defense predispose piñon pine trees to bark beetle attacks and mortality during severe drought. Our novel approach is an important step forward to yield new insights into how trees die via retrospective analysis.
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Affiliation(s)
- Monica L Gaylord
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA Present address: Forest Health Protection, USDA Forest Service, Flagstaff, AZ 86001, USA
| | - Thomas E Kolb
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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35
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Slater H, Dolan L. Introducing Tansley insights - short and timely, focussed reviews within the plant sciences. THE NEW PHYTOLOGIST 2015; 205:953-954. [PMID: 25580649 DOI: 10.1111/nph.13259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
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