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Lecomte X, Bugalho MN, Catry FX, Fernandes PM, Cera A, Caldeira MC. Ungulates mitigate the effects of drought and shrub encroachment on the fire hazard of Mediterranean oak woodlands. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2971. [PMID: 38581136 DOI: 10.1002/eap.2971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 12/16/2023] [Accepted: 01/31/2024] [Indexed: 04/08/2024]
Abstract
Climate change is increasing the frequency of droughts and the risk of severe wildfires, which can interact with shrub encroachment and browsing by wild ungulates. Wild ungulate populations are expanding due, among other factors, to favorable habitat changes resulting from land abandonment or land-use changes. Understanding how ungulate browsing interacts with drought to affect woody plant mortality, plant flammability, and fire hazard is especially relevant in the context of climate change and increasing frequency of wildfires. The aim of this study is to explore the combined effects of cumulative drought, shrub encroachment, and ungulate browsing on the fire hazard of Mediterranean oak woodlands in Portugal. In a long-term (18 years) ungulate fencing exclusion experiment that simulated land abandonment and management neglect, we investigated the population dynamics of the native shrub Cistus ladanifer, which naturally dominates the understory of woodlands and is browsed by ungulates, comparing areas with (no fencing) and without (fencing) wild ungulate browsing. We also modeled fire behavior in browsed and unbrowsed plots considering drought and nondrought scenarios. Specifically, we estimated C. ladanifer population density, biomass, and fuel load characteristics, which were used to model fire behavior in drought and nondrought scenarios. Overall, drought increased the proportion of dead C. ladanifer shrub individuals, which was higher in the browsed plots. Drought decreased the ratio of live to dead shrub plant material, increased total fuel loading, shrub stand flammability, and the modeled fire parameters, that is, rate of surface fire spread, fireline intensity, and flame length. However, total fuel load and fire hazard were lower in browsed than unbrowsed plots, both in drought and nondrought scenarios. Browsing also decreased the population density of living shrubs, halting shrub encroachment. Our study provides long-term experimental evidence showing the role of wild ungulates in mitigating drought effects on fire hazard in shrub-encroached Mediterranean oak woodlands. Our results also emphasize that the long-term effects of land abandonment can interact with climate change drivers, affecting wildfire hazard. This is particularly relevant given the increasing incidence of land abandonment.
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Affiliation(s)
- Xavier Lecomte
- Forest Research Center, Associate Laboratory TERRA, School of Agriculture, University of Lisbon, Lisbon, Portugal
- Center for Applied Ecology "Prof. Baeta Neves" (CEABN-InBIO), School of Agriculture, University of Lisbon, Lisbon, Portugal
| | - Miguel N Bugalho
- Center for Applied Ecology "Prof. Baeta Neves" (CEABN-InBIO), School of Agriculture, University of Lisbon, Lisbon, Portugal
| | - Filipe X Catry
- Center for Applied Ecology "Prof. Baeta Neves" (CEABN-InBIO), School of Agriculture, University of Lisbon, Lisbon, Portugal
| | - Paulo M Fernandes
- Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- ForestWISE-Collaborative Laboratory for Integrated Forest and Fire Management, Vila Real, Portugal
| | - Andreu Cera
- Center for Applied Ecology "Prof. Baeta Neves" (CEABN-InBIO), School of Agriculture, University of Lisbon, Lisbon, Portugal
| | - Maria C Caldeira
- Forest Research Center, Associate Laboratory TERRA, School of Agriculture, University of Lisbon, Lisbon, Portugal
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Wright BR, Nipper M, Nipper N, Merson SD, Guest T. Mortality rates of desert vegetation during high‐intensity drought at
Uluru‐Kata
Tjuta National Park, Central Australia. AUSTRAL ECOL 2023. [DOI: 10.1111/aec.13290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Boyd R. Wright
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
- School of Agriculture and Food Science University of Queensland Brisbane Queensland Australia
- Botany, School of Environmental and Rural Science University of New England Armidale New South Wales Australia
| | - Martin Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | - Nathan Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | | | - Tracey Guest
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
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3
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Andres SE, Emery NJ, Rymer PD, Powell JR. Soil chemistry and fungal communities are associated with dieback in an Endangered Australian shrub. PLANT AND SOIL 2023; 483:47-70. [PMID: 36211803 PMCID: PMC9525234 DOI: 10.1007/s11104-022-05724-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/23/2022] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS Field surveys across known populations of the Endangered Persoonia hirsuta (Proteaceae) in 2019 suggested the soil environment may be associated with dieback in this species. To explore how characteristics of the soil environment (e.g., pathogens, nutrients, soil microbes) relate to dieback, a soil bioassay (Experiment 1) was conducted using field soils from two dieback effected P. hirsuta populations. Additionally, a nitrogen addition experiment (Experiment 2) was conducted to explore how the addition of soil nitrogen impacts dieback. METHODS The field soils were baited for pathogens, and soil physiochemical and microbial community characteristics were assessed and related to dieback among plants in the field and nursery-grown plants inoculated with the same field soils. Roots from inoculated plants were harvested to confirm the presence of soil pathogens and root-associated endophytes. Using these isolates, a dual culture antagonism assay was performed to examine competition among these microbes and identify candidate pathogens or pathogen antagonists. RESULTS Dieback among plants in the field and Experiment 1 was associated with soil physiochemical properties (nitrogen and potassium), and soil microbes were identified as significant indicators of healthy and dieback-affected plants. Plants in Experiment 2 exhibited greater dieback when treated with elevated nitrogen. Additionally, post-harvest culturing identified fungi and other soil pathogens, some of which exhibited antagonistic behavior. CONCLUSION This study identified candidate fungi and soil physiochemical properties associated with observed dieback and dieback resistance in an Endangered shrub and provides groundwork for further exploring what drives dieback and how it can be managed to promote the conservation of wild populations. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11104-022-05724-7.
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Affiliation(s)
- Samantha E. Andres
- Hawkesbury Institute for the Environment, Richmond, New South Wales 2753 Australia
| | - Nathan J. Emery
- The Australian PlantBank, Australian Botanic Garden, Australian Institute of Botanical Science, Mount Annan, New South Wales 2567 Australia
| | - Paul D. Rymer
- Hawkesbury Institute for the Environment, Richmond, New South Wales 2753 Australia
| | - Jeff R. Powell
- Hawkesbury Institute for the Environment, Richmond, New South Wales 2753 Australia
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Westward Expansion by Juniperus virginiana of the Eastern United States and Intersection with Western Juniperus Species in a Novel Assemblage. FORESTS 2022. [DOI: 10.3390/f13010101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Eastern redcedar (Juniperus virginiana L.) is increasing in density in the eastern United States and expanding in range to the west, while western Juniperus species also are increasing and expanding, creating the potential for a novel assemblage. I estimated range expansion and intersection by comparing recent USDA Forest Service Forest Inventory and Analysis surveys (mean year = 2009) to the oldest available surveys (mean year = 1981), with adjustments for sampling changes, and predicted climate envelopes during the following year ranges: 1500–1599, 1800–1849, 1850–1899, 1900–1949, and 1960–1989. During approximately 28 years, eastern redcedar range expanded by about 54 million ha (based on ≥0.5% of total stems ≥12.7 cm in diameter in ecological subsections). Combined range of western species of juniper did not expand. Range intersection of eastern redcedar and western Juniperus species totaled 200,000 km2 and increased by 31,600 km2 over time, representing a novel assemblage of eastern and western species. Predicted ranges during the other time intervals were 94% to 98% of predicted area during 1960–1989, suggesting major climate conditions have been suitable for centuries. The southern western Juniperus species and Rocky Mountain juniper (Juniperus scopulorum Sarg.) have the greatest potential for intersection with eastern redcedar, whereas eastern redcedar may have concluded westward expansion.
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5
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Mokarram M, Pourghasemi HR, Hu M, Zhang H. Determining and forecasting drought susceptibility in southwestern Iran using multi-criteria decision-making (MCDM) coupled with CA-Markov model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 781:146703. [PMID: 33798887 DOI: 10.1016/j.scitotenv.2021.146703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/02/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Forecasting drought and determining relevant data to predict drought are an important topic for decision-makers and planners. It is critical to predicting drought in the south of Fars province, an important agricultural center in Iran located in arid and semi-arid climates. The purpose of this study was to generate a drought map in 2019 using 12 parameters: altitude, aridity index, erosion, groundwater depth, land use, PET (Potential evapotranspiration), precipitation days, precipitation, slope, soil texture, soil salinity, and distance to river, and predict drought maps in 2030 and 2040 using the cellular automata (CA)-Markov model spatially. The fuzzy method was first used to homogenize the data. Next, by evaluating each parameter, the weight of each parameter was calculated using the analytic hierarchy process (AHP), and a map of drought-prone areas was generated. The results of the fuzzy-AHP method showed that the eastern and southeastern regions of the study area were prone to drought. The four most predictive parameters in causing drought, i.e., aridity index, PET, precipitation, and soil texture, were selected using the Best search method and were then chosen as the input to determine drought mapping using the fuzzy and AHP methods. Finally, the CA-Markov model was used to predict future drought maps, and the results showed that in 2030 and 2040 the drought situation in the east and south of the study area would intensify.
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Affiliation(s)
- Marzieh Mokarram
- Department of Range and Watershed Management, College of Agriculture and Natural Resources of Darab, Shiraz University, Shiraz, Iran.
| | - Hamid Reza Pourghasemi
- Department of Natural Resources and Environmental Engineering, College of Agriculture, Shiraz University, Shiraz, Iran
| | - Ming Hu
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, United States of America.
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, Cleveland, OH 44106, United States of America.
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Smith‐Martin CM, Skelton RP, Johnson KM, Lucani C, Brodribb TJ. Lack of vulnerability segmentation among woody species in a diverse dry sclerophyll woodland community. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13519] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Chris M. Smith‐Martin
- Department of Ecology, Evolution and Evolutionary Biology Columbia University New York NY USA
| | - Robert Paul Skelton
- South African Environmental Observation NetworkKirstenbosch Botanical Gardens Cape Town South Africa
| | - Kate M. Johnson
- School of Biological Sciences University of Tasmania Hobart TAS Australia
| | - Christopher Lucani
- School of Biological Sciences University of Tasmania Hobart TAS Australia
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Apgaua DMG, Tng DYP, Forbes SJ, Ishida YF, Vogado NO, Cernusak LA, Laurance SGW. Elevated temperature and CO2 cause differential growth stimulation and drought survival responses in eucalypt species from contrasting habitats. TREE PHYSIOLOGY 2019; 39:1806-1820. [PMID: 31768554 DOI: 10.1093/treephys/tpz095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/08/2019] [Accepted: 08/15/2019] [Indexed: 06/10/2023]
Abstract
Climate change scenarios predict increasing atmospheric CO2 concentrations ([CO2]), temperatures and droughts in tropical regions. Individually, the effects of these climate factors on plants are well established, whereas experiments on the interactive effects of a combination of factors are rare. Moreover, how these environmental factors will affect tree species along a wet to dry gradient (e.g., along tropical forest-savanna transitions) remains to be investigated. We hypothesized that under the simulated environmental conditions, plant growth, physiological performance and survivorship would vary in a manner consistent with the species' positions of origin along this gradient. In a glasshouse experiment, we raised seedlings of three Eucalyptus species, each occurring naturally in a wet forest, savanna and forest-savanna ecotone, respectively. We evaluated the effect of drought, elevated temperature (4 °C above ambient glasshouse temperature of 22 °C) and elevated temperature in combination with elevated [CO2] (400 ppm [CO2] above ambient of 400 ppm), on seedling growth, survivorship and physiological responses (photosynthesis, stomatal conductance and water-use efficiency). Elevated temperature under ambient [CO2] had little effect on growth, biomass and plant performance of well-watered seedlings, but hastened mortality in drought-affected seedlings, affecting the forest and ecotone more strongly than the savanna species. In contrast, elevated [CO2] in combination with elevated temperatures delayed the appearance of drought stress symptoms and enhanced survivorship in drought-affected seedlings, with the savanna species surviving the longest, followed by the ecotone and forest species. Elevated [CO2] in combination with elevated temperatures also enhanced growth and biomass and photosynthesis in well-watered seedlings of all species, but modified shoot:root biomass partitioning and stomatal conductance differentially across species. Our study highlights the need for a better understand of the interactive effects of elevated [CO2], temperature and drought on plants and the potential to upscale these insights for understanding biome changes.
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Affiliation(s)
- Deborah M G Apgaua
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
| | - David Y P Tng
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
- Centre for Rainforest Studies at the School for Field Studies, Yungaburra, Queensland 4872, Australia
- Instituto de Biologia, Universidade Federal da Bahia, R. Barão Jeremoabo, Ondina, Salvador, Bahia 40170-115, Brazil
| | - Samantha J Forbes
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
| | - Yoko F Ishida
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
| | - Nara O Vogado
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
| | - Lucas A Cernusak
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
| | - Susan G W Laurance
- Centre for Tropical Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, 14-88 McGregor Rd, Smithfield, Queensland 4878, Australia
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8
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Winkler DE, Belnap J, Hoover D, Reed SC, Duniway MC. Shrub persistence and increased grass mortality in response to drought in dryland systems. GLOBAL CHANGE BIOLOGY 2019; 25:3121-3135. [PMID: 31025434 DOI: 10.1111/gcb.14667] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/15/2019] [Indexed: 05/13/2023]
Abstract
Droughts in the southwest United States have led to major forest and grassland die-off events in recent decades, suggesting plant community and ecosystem shifts are imminent as native perennial grass populations are replaced by shrub- and invasive plant-dominated systems. These patterns are similar to those observed in arid and semiarid systems around the globe, but our ability to predict which species will experience increased drought-induced mortality in response to climate change remains limited. We investigated meteorological drought-induced mortality of nine dominant plant species in the Colorado Plateau Desert by experimentally imposing a year-round 35% precipitation reduction for eight continuous years. We distributed experimental plots across numerous plant, soil, and parent material types, resulting in 40 distinct sites across a 4,500 km2 region of the Colorado Plateau Desert. For all 8 years, we tracked c. 400 individual plants and evaluated mortality responses to treatments within and across species, and through time. We also examined the influence of abiotic and biotic site factors in driving mortality responses. Overall, high mortality trends were driven by dominant grass species, including Achnatherum hymenoides, Pleuraphis jamesii, and Sporobolus cryptandrus. Responses varied widely from year to year and dominant shrub species were generally resistant to meteorological drought, likely due to their ability to access deeper soil water. Importantly, mortality increased in the presence of invasive species regardless of treatment, and native plant die-off occurred even under ambient conditions, suggesting that recent climate changes are already negatively impacting dominant species in these systems. Results from this long-term drought experiment suggest major shifts in community composition and, as a result, ecosystem function. Patterns also show that, across multiple soil and plant community types, native perennial grass species may be replaced by shrubs and invasive annuals in the Colorado Plateau Desert.
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Affiliation(s)
- Daniel E Winkler
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah
| | - Jayne Belnap
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah
| | - David Hoover
- Rangeland Resources & Systems Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Fort Collins, Colorado
| | - Sasha C Reed
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah
| | - Michael C Duniway
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah
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9
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Martinez-Vilalta J, Anderegg WRL, Sapes G, Sala A. Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. THE NEW PHYTOLOGIST 2019; 223:22-32. [PMID: 30560995 DOI: 10.1111/nph.15644] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/06/2018] [Indexed: 05/23/2023]
Abstract
Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality.
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Affiliation(s)
- Jordi Martinez-Vilalta
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193, Barcelona, Spain
| | | | - Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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10
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A New Wetness Index to Evaluate the Soil Water Availability Influence on Gross Primary Production of European Forests. CLIMATE 2019. [DOI: 10.3390/cli7030042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rising temperature, drought and more-frequent extreme climatic events have been predicted for the next decades in many regions around the globe. In this framework, soil water availability plays a pivotal role in affecting vegetation productivity, especially in arid or semi-arid environments. However, direct measurements of soil moisture are scarce, and modeling estimations are still subject to biases. Further investigation on the effect of soil moisture on plant productivity is required. This study aims at analyzing spatio-temporal variations of a modified temperature vegetation wetness index (mTVWI), a proxy of soil moisture, and evaluating its effect on gross primary production (GPP) in forests. The study was carried out in Europe on 19 representative tree species during the 2000–2010 time period. Results outline a north–south gradient of mTVWI with minimum values (low soil water availability) in Southern Europe and maximum values (high soil water availability) in Northeastern Europe. A low soil water availability negatively affected GPP from 20 to 80%, as a function of site location, tree species, and weather conditions. Such a wetness index improves our understanding of water stress impacts, which is crucial for predicting the response of forest carbon cycling to drought and aridity.
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Preisler Y, Tatarinov F, Grünzweig JM, Bert D, Ogée J, Wingate L, Rotenberg E, Rohatyn S, Her N, Moshe I, Klein T, Yakir D. Mortality versus survival in drought‐affected Aleppo pine forest depends on the extent of rock cover and soil stoniness. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13302] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yakir Preisler
- Earth and Planetary Science Department Weizmann Institute of Science Rehovot Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
| | - Fyodor Tatarinov
- Earth and Planetary Science Department Weizmann Institute of Science Rehovot Israel
| | - José M. Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
| | - Didier Bert
- BIOGECO INRA, University of Bordeaux Cestas France
| | - Jérôme Ogée
- ISPA, Bordeaux Science Agro INRA Villenave d'Ornon France
| | - Lisa Wingate
- ISPA, Bordeaux Science Agro INRA Villenave d'Ornon France
| | - Eyal Rotenberg
- Earth and Planetary Science Department Weizmann Institute of Science Rehovot Israel
| | - Shani Rohatyn
- Earth and Planetary Science Department Weizmann Institute of Science Rehovot Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
| | - Nir Her
- Forestry Department KKL Gilat Israel
| | | | - Tamir Klein
- Plant & Environmental Sciences Department Weizmann Institute of Science Rehovot Israel
| | - Dan Yakir
- Earth and Planetary Science Department Weizmann Institute of Science Rehovot Israel
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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: 3] [Impact Index Per Article: 0.6] [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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A tale of ENSO, PDO, and increasing aridity impacts on drought-deciduous shrubs in the Death Valley region. Oecologia 2018; 187:879-895. [PMID: 29955998 DOI: 10.1007/s00442-018-4200-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 06/05/2018] [Indexed: 10/28/2022]
Abstract
Germination, establishment, phenology, and death among three drought-deciduous shrubs were influenced by ENSO/PDO and precipitation, based on 37 years of annual surveys. Encelia farinosa forms near monospecific stands on slopes, whereas E. frutescens and Ambrosia salsola dominate wash habitats. All shrubs exhibited phenological coherence. While germination, establishment, and mortality patterns were similar among wash species, these dynamics contrasted with E. farinosa on slopes. Germination was associated with El Niño years. Slope plant establishment was dependent on precipitation in the subsequent year, but not evidently so in wash species. Major mortality events were episodic, with Encelia mortality just as likely to occur in years with below or above average precipitation. In both Encelia species, mortality was associated with transitions to a cold PDO phase. In E. frutescens this response was more rapid, whereas in E. farinosa mortality lagged 1 year, resulting in contrasting slope-wash mortality patterns. 50% of newly established shrubs died within 5, 5, and 18 years for E. frutescens, E. farinosa, and A. salsola, respectively. The 90% mortality ages were 26 years for E. frutescens, 24 years for E. farinosa, and 51 years for A. salsola. While maximum life expectancies are unknown, estimated maximum life expectancies were 56, 66, and 86 years for E. frutescens, E. farinosa, and A. salsola, respectively. Overall, as the climate has become more arid over the past four decades, the populations in both slope and wash habitats have exhibited similar responses: reduced shrub abundances and reduced total supportable leaf areas.
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Overstory Structure and Surface Cover Dynamics in the Decade Following the Hayman Fire, Colorado. FORESTS 2018. [DOI: 10.3390/f9030152] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Moran E, Lauder J, Musser C, Stathos A, Shu M. The genetics of drought tolerance in conifers. THE NEW PHYTOLOGIST 2017; 216:1034-1048. [PMID: 28895167 DOI: 10.1111/nph.14774] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/27/2017] [Indexed: 05/20/2023]
Abstract
Contents 1034 I. 1034 II. 1035 III. 1037 IV. 1038 V. 1042 VI. 1043 VII. 1045 References 1045 SUMMARY: As temperatures warm and precipitation patterns shift as a result of climate change, interest in the identification of tree genotypes that will thrive under more arid conditions has grown. In this review, we discuss the multiple definitions of 'drought tolerance' and the biological processes involved in drought responses. We describe the three major approaches taken in the study of genetic variation in drought responses, the advantages and shortcomings of each, and what each of these approaches has revealed about the genetic basis of adaptation to drought in conifers. Finally, we discuss how a greater knowledge of the genetics of drought tolerance may aid forest management, and provide recommendations for how future studies may overcome the limitations of past approaches. In particular, we urge a more direct focus on survival, growth and the traits that directly predict them (rather than on proxies, such as water use efficiency), combining research approaches with complementary strengths and weaknesses, and the inclusion of a wider range of taxa and life stages.
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Affiliation(s)
- Emily Moran
- UC Merced, 5200 N Lake Rd, Merced, CA, 95343, USA
| | | | - Cameron Musser
- Yale School of Forestry & Environmental Studies, 195 Prospect Street, New Haven, CT, 06511, USA
| | | | - Mengjun Shu
- UC Merced, 5200 N Lake Rd, Merced, CA, 95343, USA
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16
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Carnwath G, Nelson C. Effects of biotic and abiotic factors on resistance versus resilience of Douglas fir to drought. PLoS One 2017; 12:e0185604. [PMID: 28973008 PMCID: PMC5626460 DOI: 10.1371/journal.pone.0185604] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022] Open
Abstract
Significant increases in tree mortality due to drought-induced physiological stress have been documented worldwide. This trend is likely to continue with increased frequency and severity of extreme drought events in the future. Therefore, understanding the factors that influence variability in drought responses among trees will be critical to predicting ecosystem responses to climate change and developing effective management actions. In this study, we used hierarchical mixed-effects models to analyze drought responses of Pseudotsuga menziesii in 20 unmanaged forests stands across a broad range of environmental conditions in northeastern Washington, USA. We aimed to 1) identify the biotic and abiotic attributes most closely associated with the responses of individual trees to drought and 2) quantify the variability in drought responses at different spatial scales. We found that growth rates and competition for resources significantly affected resistance to a severe drought event in 2001: slow-growing trees and trees growing in subordinate canopy positions and/or with more neighbors suffered greater declines in radial growth during the drought event. In contrast, the ability of a tree to return to normal growth when climatic conditions improved (resilience) was unaffected by competition or relative growth rates. Drought responses were significantly influenced by tree age: older trees were more resistant but less resilient than younger trees. Finally, we found differences between resistance and resilience in spatial scale: a significant proportion (approximately 50%) of the variability in drought resistance across the study area was at broad spatial scales (i.e. among different forest types), most likely due to differences in the total amount of precipitation received at different elevations; in contrast, variation in resilience was overwhelmingly (82%) at the level of individual trees within stands and there was no difference in drought resilience among forest types. Our results suggest that for Pseudotsuga menziesii resistance and resilience to drought are driven by different factors and vary at different spatial scales.
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Affiliation(s)
- Gunnar Carnwath
- Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
| | - Cara Nelson
- Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
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17
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Redmond MD, Kelsey KC, Urza AK, Barger NN. Interacting effects of climate and landscape physiography on piñon pine growth using an individual‐based approach. Ecosphere 2017. [DOI: 10.1002/ecs2.1681] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Miranda D. Redmond
- Department of Forest and Rangeland Stewardship Colorado State University 1472 Campus Delivery Fort Collins Colorado 80523 USA
- Ecology and Evolutionary Biology Department University of Colorado Boulder Campus Box 334, 2200 Colorado Avenue Boulder Colorado 80309 USA
| | - Katharine C. Kelsey
- Environmental Studies Program University of Colorado Boulder Campus Box 399, 2200 Colorado Avenue Boulder Colorado 80309 USA
| | - Alexandra K. Urza
- Department of Natural Resources and Environmental Science Program in Ecology, Evolution and Conservation Biology University of Nevada Reno Nevada 89557 USA
| | - Nichole N. Barger
- Ecology and Evolutionary Biology Department University of Colorado Boulder Campus Box 334, 2200 Colorado Avenue Boulder Colorado 80309 USA
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18
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Greenwood S, Ruiz-Benito P, Martínez-Vilalta J, Lloret F, Kitzberger T, Allen CD, Fensham R, Laughlin DC, Kattge J, Bönisch G, Kraft NJB, Jump AS. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area. Ecol Lett 2017; 20:539-553. [PMID: 28220612 DOI: 10.1111/ele.12748] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/23/2016] [Accepted: 01/16/2017] [Indexed: 12/18/2022]
Abstract
Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1 year-1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.
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Affiliation(s)
- Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,Forest Ecology and Restoration Group, Life Sciences Department, Universidad de Alcalá, Science Building, Alcalá de Henares, 28805, Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Francisco Lloret
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, Río Negro, Argentina
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, New Mexico, 87544, USA
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia.,School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Daniel C Laughlin
- Environmental Research Institute and School of Science, University of Waikato, Hamilton, New Zealand
| | - Jens Kattge
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Gerhard Bönisch
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany
| | - Nathan J B Kraft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain
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19
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Ibáñez B, Gómez-Aparicio L, Ávila JM, Pérez-Ramos IM, Marañón T. Effects of Quercus suber Decline on Woody Plant Regeneration: Potential Implications for Successional Dynamics in Mediterranean Forests. Ecosystems 2016. [DOI: 10.1007/s10021-016-0044-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Climatic events inducing die-off in Mediterranean shrublands: are species’ responses related to their functional traits? Oecologia 2016; 180:961-73. [DOI: 10.1007/s00442-016-3550-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 01/04/2016] [Indexed: 11/25/2022]
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21
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Redmond MD, Cobb NS, Clifford MJ, Barger NN. Woodland recovery following drought-induced tree mortality across an environmental stress gradient. GLOBAL CHANGE BIOLOGY 2015; 21:3685-95. [PMID: 26089027 DOI: 10.1111/gcb.12976] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/28/2015] [Indexed: 05/26/2023]
Abstract
Recent droughts and increasing temperatures have resulted in extensive tree mortality across the globe. Understanding the environmental controls on tree regeneration following these drought events will allow for better predictions of how these ecosystems may shift under a warmer, drier climate. Within the widely distributed piñon-juniper woodlands of the southwestern USA, a multiyear drought in 2002-2004 resulted in extensive adult piñon mortality and shifted adult woodland composition to a juniper-dominated, more savannah-type ecosystem. Here, we used pre- (1998-2001) and 10-year post- (2014) drought stand structure data of individually mapped trees at 42 sites to assess the effects of this drought on tree regeneration across a gradient of environmental stress. We found declines in piñon juvenile densities since the multiyear drought due to limited new recruitment and high (>50%) juvenile mortality. This is in contrast to juniper juvenile densities, which increased over this time period. Across the landscape, piñon recruitment was positively associated with live adult piñon densities and soil available water capacity, likely due to their respective effects on seed and water availability. Juvenile piñon survival was strongly facilitated by certain types of nurse trees and shrubs. These nurse plants also moderated the effects of environmental stress on piñon survival: Survival of interspace piñon juveniles was positively associated with soil available water capacity, whereas survival of nursed piñon juveniles was negatively associated with perennial grass cover. Thus, nurse plants had a greater facilitative effect on survival at sites with higher soil available water capacity and perennial grass cover. Notably, mean annual climatic water deficit and elevation were not associated with piñon recruitment or survival across the landscape. Our findings reveal a clear shift in successional trajectories toward a more juniper-dominated woodland and highlight the importance of incorporating biotic interactions and soil properties into species distribution modeling approaches.
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Affiliation(s)
- Miranda D Redmond
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, 80302, USA
| | - Neil S Cobb
- Merriam Powel Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Michael J Clifford
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, NV, 89119, USA
| | - Nichole N Barger
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, CO, 80302, USA
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22
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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: 2.2] [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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23
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Limousin J, Yepez EA, McDowell NG, Pockman WT. Convergence in resource use efficiency across trees with differing hydraulic strategies in response to ecosystem precipitation manipulation. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12426] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jean‐Marc Limousin
- Department of Biology MSC03 2020 1 University of New Mexico Albuquerque New Mexico 87131‐0001 USA
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE UMR 5175 CNRS Université de Montpellier Université Paul‐Valéry EPHE 1919 route de Mende 34293 Montpellier 5 France
| | - Enrico A. Yepez
- Departamento de Ciencias del Agua y del Medio Ambiente Instituto Tecnologico de Sonora Ciudad Obregon Sonora 85000 Mexico
| | - Nate G. McDowell
- Earth and Environmental Sciences Division Los Alamos National Laboratory Los Alamos New Mexico 87545 USA
| | - William T. Pockman
- Department of Biology MSC03 2020 1 University of New Mexico Albuquerque New Mexico 87131‐0001 USA
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24
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Meddens AJH, Hicke JA, Macalady AK, Buotte PC, Cowles TR, Allen CD. Patterns and causes of observed piñon pine mortality in the southwestern United States. THE NEW PHYTOLOGIST 2015; 206:91-97. [PMID: 25494578 DOI: 10.1111/nph.13193] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Recently, widespread piñon pine die-off occurred in the southwestern United States. Here we synthesize observational studies of this event and compare findings to expected relationships with biotic and abiotic factors. Agreement exists on the occurrence of drought, presence of bark beetles and increased mortality of larger trees. However, studies disagree about the influences of stem density, elevation and other factors, perhaps related to study design, location and impact of extreme drought. Detailed information about bark beetles is seldom reported and their role is poorly understood. Our analysis reveals substantial limits to our knowledge regarding the processes that produce mortality patterns across space and time, indicating a poor ability to forecast mortality in response to expected increases in future droughts.
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Affiliation(s)
- Arjan J H Meddens
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Alison K Macalady
- School of Geography and Development and Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721-0076, USA
| | - Polly C Buotte
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Travis R Cowles
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, Jemez Mountains Field Station, Los Alamos, NM, 87544, USA
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25
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Pangle RE, Limousin JM, Plaut JA, Yepez EA, Hudson PJ, Boutz AL, Gehres N, Pockman WT, McDowell NG. Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon-juniper woodland. Ecol Evol 2015; 5:1618-38. [PMID: 25937906 PMCID: PMC4409411 DOI: 10.1002/ece3.1422] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/15/2015] [Accepted: 01/20/2015] [Indexed: 01/06/2023] Open
Abstract
Plant hydraulic conductance (ks) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine (Pinus edulis) and juniper (Juniperus monosperma) woodland. We examined the relationship between ks and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (EC) and conductance (GC). For both species, we observed significant reductions in plant transpiration (E) and ks under experimentally imposed drought. Conversely, supplemental water additions increased E and ks in both species. Interestingly, both species exhibited similar declines in ks under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant ks also reduced carbon assimilation in both species, as leaf-level stomatal conductance (gs) and net photosynthesis (An) declined strongly with decreasing ks. Finally, we observed that chronically low whole-plant ks was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy EC and GC. Our data indicate that significant reductions in ks precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon–juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more frequent and persistent regional drought in the southwestern United States.
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Affiliation(s)
- Robert E Pangle
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Jean-Marc Limousin
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE, UMR5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE 1919 Route de Mende, Montpellier Cedex 5, 34293, France
| | - Jennifer A Plaut
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Enrico A Yepez
- Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora Ciudad Obregón, Sonora, 85000, Mexico
| | - Patrick J Hudson
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Amanda L Boutz
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Nathan Gehres
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - William T Pockman
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory Los Alamos, New Mexico, 87545
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26
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Ibáñez B, Gómez-Aparicio L, Stoll P, Ávila JM, Pérez-Ramos IM, Marañón T. A neighborhood analysis of the consequences of Quercus suber decline for regeneration dynamics in Mediterranean forests. PLoS One 2015; 10:e0117827. [PMID: 25706723 PMCID: PMC4338116 DOI: 10.1371/journal.pone.0117827] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 12/31/2014] [Indexed: 11/22/2022] Open
Abstract
In forests, the vulnerable seedling stage is largely influenced by the canopy, which modifies the surrounding environment. Consequently, any alteration in the characteristics of the canopy, such as those promoted by forest dieback, might impact regeneration dynamics. Our work analyzes the interaction between canopy neighbors and seedlings in Mediterranean forests affected by the decline of their dominant species (Quercus suber). Our objective was to understand how the impacts of neighbor trees and shrubs on recruitment could affect future dynamics of these declining forests. Seeds of the three dominant tree species (Quercus suber, Olea europaea and Quercus canariensis) were sown in six sites during two consecutive years. Using a spatially-explicit, neighborhood approach we developed models that explained the observed spatial variation in seedling emergence, survival, growth and photochemical efficiency as a function of the size, identity, health, abundance and distribution of adult trees and shrubs in the neighborhood. We found strong neighborhood effects for all the performance estimators, particularly seedling emergence and survival. Tree neighbors positively affected emergence, independently of species identity or health. Alternatively, seedling survival was much lower in neighborhoods dominated by defoliated and dead Q. suber trees than in neighborhoods dominated by healthy trees. For the two oak species, these negative effects were consistent over the three years of the experimental seedlings. These results indicate that ongoing changes in species' relative abundance and canopy trees' health might alter the successional trajectories of Mediterranean oak-forests through neighbor-specific impacts on seedlings. The recruitment failure of dominant late-successional oaks in the gaps opened after Q. suber death would indirectly favor the establishment of other coexisting woody species, such as drought-tolerant shrubs. This could lead current forests to shift into open systems with lower tree cover. Adult canopy decline would therefore represent an additional factor threatening the recruitment of Quercus forests worldwide.
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Affiliation(s)
- Beatriz Ibáñez
- Instituto de Recursos Naturales y Agrobiología (IRNAS, CSIC), PO Box 1052, Sevilla 41080, Spain
| | - Lorena Gómez-Aparicio
- Instituto de Recursos Naturales y Agrobiología (IRNAS, CSIC), PO Box 1052, Sevilla 41080, Spain
| | - Peter Stoll
- Institute for Environmental Sciences, Section Conservation Biology, University of Basel, St. Johanns-Vorstadt 10, CH-4056 Basel, Switzerland
| | - José M. Ávila
- Instituto de Recursos Naturales y Agrobiología (IRNAS, CSIC), PO Box 1052, Sevilla 41080, Spain
| | - Ignacio M. Pérez-Ramos
- Instituto de Recursos Naturales y Agrobiología (IRNAS, CSIC), PO Box 1052, Sevilla 41080, Spain
| | - Teodoro Marañón
- Instituto de Recursos Naturales y Agrobiología (IRNAS, CSIC), PO Box 1052, Sevilla 41080, Spain
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27
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Patterns of herbivory-induced mortality of a dominant non-native tree/shrub (Tamarix spp.) in a southwestern US watershed. Biol Invasions 2014. [DOI: 10.1007/s10530-014-0829-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Meinzer FC, Woodruff DR, Marias DE, McCulloh KA, Sevanto S. Dynamics of leaf water relations components in co-occurring iso- and anisohydric conifer species. PLANT, CELL & ENVIRONMENT 2014; 37:2577-86. [PMID: 24661116 DOI: 10.1111/pce.12327] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 05/20/2023]
Abstract
Because iso- and anisohydric species differ in stomatal regulation of the rate and magnitude of fluctuations in shoot water potential, they may be expected to show differences in the plasticity of their shoot water relations components, but explicit comparisons of this nature have rarely been made. We subjected excised shoots of co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis to pressure-volume analysis with and without prior artificial rehydration. In J. monosperma, the shoot water potential at turgor loss (Ψ(TLP)) ranged from -3.4 MPa in artificially rehydrated shoots to -6.6 MPa in shoots with an initial Ψ of -5.5 MPa, whereas in P. edulis mean Ψ(TLP) remained at ∼ -3.0 MPa over a range of initial Ψ from -0.1 to -2.3 MPa. The shoot osmotic potential at full turgor and the bulk modulus of elasticity also declined sharply with shoot Ψ in J. monosperma, but not in P. edulis. The contrasting behaviour of J. monosperma and P. edulis reflects differences in their capacity for homeostatic regulation of turgor that may be representative of aniso- and isohydric species in general, and may also be associated with the greater capacity of J. monosperma to withstand severe drought.
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Affiliation(s)
- Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
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29
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Mitchell PJ, O'Grady AP, Hayes KR, Pinkard EA. Exposure of trees to drought-induced die-off is defined by a common climatic threshold across different vegetation types. Ecol Evol 2014; 4:1088-101. [PMID: 24772285 PMCID: PMC3997324 DOI: 10.1002/ece3.1008] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 01/22/2014] [Accepted: 01/25/2014] [Indexed: 12/30/2022] Open
Abstract
Increases in drought and temperature stress in forest and woodland ecosystems are thought to be responsible for the rise in episodic mortality events observed globally. However, key climatic drivers common to mortality events and the impacts of future extreme droughts on tree survival have not been evaluated. Here, we characterize climatic drivers associated with documented tree die-off events across Australia using standardized climatic indices to represent the key dimensions of drought stress for a range of vegetation types. We identify a common probabilistic threshold associated with an increased risk of die-off across all the sites that we examined. We show that observed die-off events occur when water deficits and maximum temperatures are high and exist outside 98% of the observed range in drought intensity; this threshold was evident at all sites regardless of vegetation type and climate. The observed die-off events also coincided with at least one heat wave (three consecutive days above the 90th percentile for maximum temperature), emphasizing a pivotal role of heat stress in amplifying tree die-off and mortality processes. The joint drought intensity and maximum temperature distributions were modeled for each site to describe the co-occurrence of both hot and dry conditions and evaluate future shifts in climatic thresholds associated with the die-off events. Under a relatively dry and moderate warming scenario, the frequency of droughts capable of inducing significant tree die-off across Australia could increase from 1 in 24 years to 1 in 15 years by 2050, accompanied by a doubling in the occurrence of associated heat waves. By defining commonalities in drought conditions capable of inducing tree die-off, we show a strong interactive effect of water and high temperature stress and provide a consistent approach for assessing changes in the exposure of ecosystems to extreme drought events.
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Affiliation(s)
- Patrick J Mitchell
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
| | - Anthony P O'Grady
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
| | - Keith R Hayes
- CSIRO Computational Informatics, Castray Esplanade Hobart, TAS, Australia
| | - Elizabeth A Pinkard
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
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Herrero A, Zamora R. Plant responses to extreme climatic events: a field test of resilience capacity at the southern range edge. PLoS One 2014; 9:e87842. [PMID: 24489971 PMCID: PMC3905046 DOI: 10.1371/journal.pone.0087842] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Accepted: 12/31/2013] [Indexed: 11/18/2022] Open
Abstract
The expected and already observed increment in frequency of extreme climatic events may result in severe vegetation shifts. However, stabilizing mechanisms promoting community resilience can buffer the lasting impact of extreme events. The present work analyzes the resilience of a Mediterranean mountain ecosystem after an extreme drought in 2005, examining shoot-growth and needle-length resistance and resilience of dominant tree and shrub species (Pinus sylvestris vs Juniperus communis, and P. nigra vs J. oxycedrus) in two contrasting altitudinal ranges. Recorded high vegetative-resilience values indicate great tolerance to extreme droughts for the dominant species of pine-juniper woodlands. Observed tolerance could act as a stabilizing mechanism in rear range edges, such as the Mediterranean basin, where extreme events are predicted to be more detrimental and recurrent. However, resistance and resilience components vary across species, sites, and ontogenetic states: adult Pinus showed higher growth resistance than did adult Juniperus; saplings displayed higher recovery rates than did conspecific adults; and P. nigra saplings displayed higher resilience than did P. sylvestris saplings where the two species coexist. P. nigra and J. oxycedrus saplings at high and low elevations, respectively, were the most resilient at all the locations studied. Under recurrent extreme droughts, these species-specific differences in resistance and resilience could promote changes in vegetation structure and composition, even in areas with high tolerance to dry conditions.
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Affiliation(s)
- Asier Herrero
- Department of Ecology, University of Granada, Granada, Andalusia, Spain ; Department of Life Sciences, University of Alcalá, Alcalá de Henares, Madrid, Spain
| | - Regino Zamora
- Department of Ecology, University of Granada, Granada, Andalusia, Spain
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Limousin JM, Bickford CP, Dickman LT, Pangle RE, Hudson PJ, Boutz AL, Gehres N, Osuna JL, Pockman WT, McDowell NG. Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes. PLANT, CELL & ENVIRONMENT 2013; 36:1812-25. [PMID: 23461476 DOI: 10.1111/pce.12089] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 02/15/2013] [Accepted: 02/25/2013] [Indexed: 05/16/2023]
Abstract
Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA.
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Affiliation(s)
- Jean-Marc Limousin
- Department of Biology, University of New Mexico, MSC03 2020, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA.
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Redmond MD, Barger NN. Tree regeneration following drought- and insect-induced mortality in piñon-juniper woodlands. THE NEW PHYTOLOGIST 2013; 200:402-412. [PMID: 23773006 DOI: 10.1111/nph.12366] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 05/14/2013] [Indexed: 05/21/2023]
Abstract
Widespread piñon (Pinus edulis) mortality occurred across the southwestern USA during 2002-2003 in response to drought and bark beetle infestations. Given the recent mortality and changes in regional climate over the past several decades, there is a keen interest in post-mortality regeneration dynamics in piñon-juniper woodlands. Here, we examined piñon and Utah juniper (Juniperus osteosperma) recruitment at 30 sites across southwestern Colorado, USA that spanned a gradient of adult piñon mortality levels (10-100%) to understand current regeneration dynamics. Piñon and juniper recruitment was greater at sites with more tree and shrub cover. Piñon recruitment was more strongly facilitated than juniper recruitment by trees and shrubs. New (post-mortality) piñon recruitment was negatively affected by recent mortality. However, mortality had no effect on piñon advanced regeneration (juveniles established pre-mortality) and did not shift juvenile piñon dominance. Our results highlight the importance of shrubs and juniper trees for the facilitation of piñon establishment and survival. Regardless of adult piñon mortality levels, areas with low tree and shrub cover may become increasingly juniper dominated as a result of the few suitable microsites for piñon establishment and survival. In areas with high piñon mortality and high tree and shrub cover, our results suggest that piñon is regenerating via advanced regeneration.
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Affiliation(s)
- Miranda D Redmond
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Nichole N Barger
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
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Herrero A, Castro J, Zamora R, Delgado-Huertas A, Querejeta JI. Growth and stable isotope signals associated with drought-related mortality in saplings of two coexisting pine species. Oecologia 2013; 173:1613-24. [DOI: 10.1007/s00442-013-2707-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 06/06/2013] [Indexed: 11/28/2022]
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Gaylord ML, Kolb TE, Pockman WT, Plaut JA, Yepez EA, Macalady AK, Pangle RE, McDowell NG. Drought predisposes piñon-juniper woodlands to insect attacks and mortality. THE NEW PHYTOLOGIST 2013; 198:567-578. [PMID: 23421561 DOI: 10.1111/nph.12174] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 01/07/2013] [Indexed: 05/08/2023]
Abstract
To test the hypothesis that drought predisposes trees to insect attacks, we quantified the effects of water availability on insect attacks, tree resistance mechanisms, and mortality of mature piñon pine (Pinus edulis) and one-seed juniper (Juniperus monosperma) using an experimental drought study in New Mexico, USA. The study had four replicated treatments (40 × 40 m plot/replicate): removal of 45% of ambient annual precipitation (H2 O-); irrigation to produce 125% of ambient annual precipitation (H2 O+); a drought control (C) to quantify the impact of the drought infrastructure; and ambient precipitation (A). Piñon began dying 1 yr after drought initiation, with higher mortality in the H2 O- treatment relative to other treatments. Beetles (bark/twig) were present in 92% of dead trees. Resin duct density and area were more strongly affected by treatments and more strongly associated with piñon mortality than direct measurements of resin flow. For juniper, treatments had no effect on insect resistance or attacks, but needle browning was highest in the H2 O- treatment. Our results provide strong evidence that ≥ 1 yr of severe drought predisposes piñon to insect attacks and increases mortality, whereas 3 yr of the same drought causes partial canopy loss in juniper.
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Affiliation(s)
- Monica L Gaylord
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Thomas E Kolb
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - William T Pockman
- Department of Biology, MSC03 2020, 1 University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Jennifer A Plaut
- Department of Biology, MSC03 2020, 1 University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Enrico A Yepez
- Department of Biology, MSC03 2020, 1 University of New Mexico, Albuquerque, NM, 87131-0001, USA
- Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora, Ciudad Obregón México, 85000, México
| | - Alison K Macalady
- School of Geography and Development and Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, USA
| | - Robert E Pangle
- Department of Biology, MSC03 2020, 1 University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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Adams HD, Germino MJ, Breshears DD, Barron-Gafford GA, Guardiola-Claramonte M, Zou CB, Huxman TE. Nonstructural leaf carbohydrate dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism. THE NEW PHYTOLOGIST 2013; 197:1142-1151. [PMID: 23311898 DOI: 10.1111/nph.12102] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/04/2012] [Indexed: 05/04/2023]
Abstract
Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function. We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species.
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Affiliation(s)
- Henry D Adams
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Matthew J Germino
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Snake River Field Station, 970 Lusk St, Boise, ID, 83706, USA
- Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA
| | - David D Breshears
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | | | | | - Chris B Zou
- Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Travis E Huxman
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
- Center for Environmental Biology, University of California, Irvine, CA, 92617, USA
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Gustafson EJ, Sturtevant BR. Modeling Forest Mortality Caused by Drought Stress: Implications for Climate Change. Ecosystems 2012. [DOI: 10.1007/s10021-012-9596-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kover PX, Mott R. Mapping the genetic basis of ecologically and evolutionarily relevant traits in Arabidopsis thaliana. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:212-7. [PMID: 22401882 DOI: 10.1016/j.pbi.2012.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/11/2012] [Accepted: 02/09/2012] [Indexed: 05/04/2023]
Abstract
There has been a long standing interest in the relationship between genetic and phenotypic variation in natural populations, in order to understand the genetic basis of adaptation and to discover natural alleles to improve crops. Here we review recent developments in mapping approaches that have significantly improved our ability to identify causal polymorphism explaining natural variation in ecological and evolutionarily relevant traits. However, challenges in interpreting these discoveries remain. In particular, we need more detailed transcriptomic, epigenomic, and gene network data to help understand the mechanisms behind identified associations. Also, more studies need to be performed under field conditions or using experimental evolution to determine whether polymorphisms identified in the lab are relevant for adaptation and improvement under natural conditions.
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Affiliation(s)
- Paula X Kover
- University of Bath, Department of Biology and Biochemistry, Claverton Down, BA2 7AY, UK.
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Long-Term Tree Cover Dynamics in a Pinyon-Juniper Woodland: Climate-Change-Type Drought Resets Successional Clock. Ecosystems 2011. [DOI: 10.1007/s10021-011-9458-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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