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Wittemann M, Mujawamariya M, Ntirugulirwa B, Uwizeye FK, Zibera E, Manzi OJL, Nsabimana D, Wallin G, Uddling J. Plasticity and implications of water-use traits in contrasting tropical tree species under climate change. PHYSIOLOGIA PLANTARUM 2024; 176:e14326. [PMID: 38708565 DOI: 10.1111/ppl.14326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/12/2024] [Indexed: 05/07/2024]
Abstract
Plants face a trade-off between hydraulic safety and growth, leading to a range of water-use strategies in different species. However, little is known about such strategies in tropical trees and whether different water-use traits can acclimate to warming. We studied five water-use traits in 20 tropical tree species grown at three different altitudes in Rwanda (RwandaTREE): stomatal conductance (gs), leaf minimum conductance (gmin), plant hydraulic conductance (Kplant), leaf osmotic potential (ψo) and net defoliation during drought. We also explored the links between these traits and growth and mortality data. Late successional (LS) species had low Kplant, gs and gmin and, thus, low water loss, while low ψo helped improve leaf water status during drought. Early successional (ES) species, on the contrary, used more water during both moist and dry conditions and exhibited pronounced drought defoliation. The ES strategy was associated with lower mortality and more pronounced growth enhancement at the warmer sites compared to LS species. While Kplant and gmin showed downward acclimation in warmer climates, ψo did not acclimate and gs measured at prevailing temperature did not change. Due to distinctly different water use strategies between successional groups, ES species may be better equipped for a warmer climate as long as defoliation can bridge drought periods.
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Affiliation(s)
- Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
- Rwanda Agriculture and Animal Resources Development Board (RAB), Kigali, Rwanda
- Rwanda Forestry Authority, Muhanga, Rwanda
| | - Felicien K Uwizeye
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Etienne Zibera
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Olivier Jean Leonce Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Integrated Polytechnic Regional College-Kitabi, Rwanda Polytechnic, Huye, Rwanda
| | - Donat Nsabimana
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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Guo H, Wang Y, Li G, Du S. Effects of Rainfall Exclusion Treatment on Photosynthetic Characteristics of Black Locust in the Sub-Humid Region of the Loess Plateau, China. PLANTS (BASEL, SWITZERLAND) 2024; 13:704. [PMID: 38475549 DOI: 10.3390/plants13050704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024]
Abstract
The mesic-origin species Robinia pseudoacacia L. (black locust) is widely planted in the semiarid and sub-humid areas of the Loess Plateau for the reforestation of vegetation-degraded land. Under the scenario of changing precipitation patterns, exploring the response of photosynthesis to drought allows us to assess the risk to sustainable development of these plantations. In this study, paired plots were established including the control and a treatment of 30% exclusion of throughfall (since 2018). The photosynthetic characteristics were investigated using a portable photosynthesis system for four periods in the full-leaf growing season of 2021-2022, the fourth and fifth years, on both treated and controlled sampling trees. Leaf gas exchange parameters derived from diurnal changing patterns, light response curves, and CO2 response curves showed significant differences except for period II (9-11 September 2021) between the two plots. The photosynthetic midday depression was observed in 2022 in the treated plot. Meanwhile, the decline of net photosynthetic rate in the treated plot was converted from stomatal limitation to non-stomatal limitation. Furthermore, we observed that black locust adapted to long-term water deficiency by reducing stomatal conductance, increasing water use efficiency and intrinsic water use efficiency. The results demonstrate that reduction in precipitation would cause photosynthesis decrease, weaken the response sensitivity to light and CO2, and potentially impair photosynthetic resilience of the plantations. They also provide insights into the changes in photosynthetic functions under global climate change and a reference for management of plantations.
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Affiliation(s)
- Haining Guo
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yiran Wang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Guoqing Li
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
| | - Sheng Du
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
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3
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Milligan PD, Martin TA, Pringle EG, Prior KM, Palmer TM. Symbiotic ant traits produce differential host-plant carbon and water dynamics in a multi-species mutualism. Ecology 2023; 104:e3880. [PMID: 36199213 DOI: 10.1002/ecy.3880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/28/2022] [Accepted: 07/28/2022] [Indexed: 02/01/2023]
Abstract
Cooperative interactions may frequently be reinforced by "partner fidelity feedback," in which high- or low-quality partners drive positive feedbacks with high or low benefits for the host, respectively. Benefits of plant-animal mutualisms for plants have been quantified almost universally in terms of growth or reproduction, but these are only two of many sinks to which a host-plant allocates its resources. By investigating how partners to host-plants impact two fundamental plant resources, carbon and water, we can better characterize plant-partner fidelity and understand how plant-partner mutualisms may be modulated by resource dynamics. In Laikipia, Kenya, four ant species compete for Acacia drepanolobium host-plants. These ants differ in multiple traits, from nectar consumption to host-plant protection. Using a 5-year ant removal experiment, we compared carbon fixation, leaf water status, and stem non-structural carbohydrate concentrations for adult ant-plants with and without ant partners. Removal treatments showed that the ants differentially mediate tree carbon and/or water resources. All three ant species known to be aggressive against herbivores were linked to benefits for host-plant resources, but only the two species that defend but do not prune the host, Crematogaster mimosae and Tetraponera penzigi, increased tree carbon fixation. Of these two species, only the nectivore C. mimosae increased tree simple sugars. Crematogaster nigriceps, which defends the tree but also castrates flowers and prunes meristems, was linked only to lower tree water stress approximated by pre-dawn leaf water potential. In contrast to those defensive ants, Crematogaster sjostedti, a poor defender that displaces other ants, was linked to lower tree carbon fixation. Comparing the effects of the four ant species across control trees suggests that differential ant occupancy drives substantial differences in carbon and water supply among host trees. Our results highlight that ant partners can positively or negatively impact carbon and/or water relations for their host-plant, and we discuss the likelihood that carbon- and water-related partner fidelity feedback loops occur across ant-plant mutualisms.
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Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya.,Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Timothy A Martin
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, Florida, USA
| | - Elizabeth G Pringle
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Kirsten M Prior
- Department of Biology, SUNY Binghamton, Binghamton, New York, USA
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya
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Hiiragi K, Matsuo N, Sakai S, Kawahara K, Ichie T, Kenzo T, Aurelia DC, Kume T, Nakagawa M. Water uptake patterns of tropical canopy trees in Borneo: species-specific and temporal variation and relationships with aboveground traits. TREE PHYSIOLOGY 2022; 42:1928-1942. [PMID: 35656927 DOI: 10.1093/treephys/tpac061] [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: 10/16/2021] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Root water uptake depth and its temporal variation are important determinants of tree mortality, resource partitioning and drought resistance; however, their effects on tropical trees remain poorly understood. In this study, we investigated interspecific differences in water uptake depth and its temporal variation using stable isotope analysis and examined the relationships between water uptake depth and aboveground traits in a humid aseasonal tropical rainforest in Borneo. Species-specific differences in water uptake depth were examined for six dominant dipterocarp species. Temporal variation in water uptake depth for various canopy trees was assessed in three periods with different soil moisture conditions. We then examined the relationships between water uptake depth and aboveground traits including wood density, maximum tree height, flowering frequency and growth rate. Dipterocarpus globosus appeared to be more reliant on deep water resources than the other dipterocarp species. Water uptake from the soil layers varied among the three sampling periods. Trees generally utilized deeper soil water during the second driest sampling period, when temperatures were lowest. During the driest and wettest sampling periods, species with higher flowering frequencies tended to preferentially uptake deep soil water. These results suggest that low temperature and soil moisture promote increased deep soil water uptake in the study region. Dynamic relationships between water uptake patterns and aboveground tree traits may be related to resource partitioning among co-existing species.
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Affiliation(s)
- Katsuura Hiiragi
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Naoko Matsuo
- Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan
| | - Shoko Sakai
- Center for Ecological Research, Kyoto University, Otsu 520-2113, Japan
| | - Kazuma Kawahara
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Tomoaki Ichie
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Japan
| | - Tanaka Kenzo
- Japan International Research Center for Agricultural Sciences, Tsukuba 305-8686, Japan
| | - Dulce Chung Aurelia
- Research, Development and Innovation Division, Forest Department Sarawak, 93250 Kuching, Sarawak, Malaysia
| | - Tomonori Kume
- Kasuya Research Forest, Kyusyu University, Sasaguri, Kasuya, Fukuoka 811-2415, Japan
| | - Michiko Nakagawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
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5
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Kamakura M, Kosugi Y, Takanashi S, Matsuo N, Uemura A, Lion M. Temporal fluctuation of patchy stomatal closure in leaves of <i>Dipterocarpus sublamellatus</i> at upper canopy in Peninsular Malaysia over the last decade. TROPICS 2021. [DOI: 10.3759/tropics.ms21-05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mai Kamakura
- Graduate School of Agriculture, Kyoto University
| | | | - Satoru Takanashi
- Forestry and Forest Products Research Institute, Kansai Research Center
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Osone Y, Hashimoto S, Kenzo T. Verification of our empirical understanding of the physiology and ecology of two contrasting plantation species using a trait database. PLoS One 2021; 16:e0254599. [PMID: 34843472 PMCID: PMC8629320 DOI: 10.1371/journal.pone.0254599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/12/2021] [Indexed: 11/18/2022] Open
Abstract
The effects of climate change on forest ecosystems take on increasing importance more than ever. Information on plant traits is a powerful predictor of ecosystem dynamics and functioning. We reviewed the major ecological traits, such as foliar gas exchange and nutrients, xylem morphology and drought tolerance, of Cryptomeria japonica and Chamaecyparis obtusa, which are major timber species in East Asia, especially in Japan, by using a recently developed functional trait database for both species (SugiHinokiDB). Empirically, C. obtusa has been planted under drier conditions, whereas C. japonica, which grows faster but thought to be less drought tolerant, has been planted under wetter conditions. Our analysis generally support the empirical knowledge: The maximum photosynthetic rate, stomatal conductance, foliar nutrient content and soil-to-foliage hydraulic conductance were higher in C. japonica than in C. obtusa. In contrast, the foliar turgor loss point and xylem pressure corresponding to 50% conductivity, which indicate drought tolerance, were lower in C. obtusa and are consistent with the drier habitat of C. obtusa. Ontogenetic shifts were also observed; as the age and height of the trees increased, foliar nutrient concentrations, foliar minimum midday water potential and specific leaf area decreased in C. japonica, suggesting that nutrient and water limitation occurs with the growth. In C. obtusa, the ontogenetic shits of these foliar traits were less pronounced. Among the Cupressaceae worldwide, the drought tolerance of C. obtusa, as well as C. japonica, was not as high. This may be related to the fact that the Japanese archipelago has historically not been subjected to strong dryness. The maximum photosynthetic rate showed intermediate values within the family, indicating that C. japonica and C. obtusa exhibit relatively high growth rates in the Cupressaceae family, and this is thought to be the reason why they have been selected as economically suitable timber species in Japanese forestry. This study clearly demonstrated that the plant trait database provides us a promising opportunity to verify out empirical knowledge of plantation management and helps us to understand effect of climate change on plantation forests by using trait-based modelling.
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Affiliation(s)
- Yoko Osone
- Forestry and Forest Products Research Institute, Tsukuba, Japan
| | - Shoji Hashimoto
- Forestry and Forest Products Research Institute, Tsukuba, Japan
| | - Tanaka Kenzo
- Forestry and Forest Products Research Institute, Tsukuba, Japan
- Japan International Research Center for Agricultural Sciences, Tsukuba, Japan
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7
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Vargas G G, Brodribb TJ, Dupuy JM, González-M R, Hulshof CM, Medvigy D, Allerton TAP, Pizano C, Salgado-Negret B, Schwartz NB, Van Bloem SJ, Waring BG, Powers JS. Beyond leaf habit: generalities in plant function across 97 tropical dry forest tree species. THE NEW PHYTOLOGIST 2021; 232:148-161. [PMID: 34171131 DOI: 10.1111/nph.17584] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 06/15/2021] [Indexed: 05/12/2023]
Abstract
Leaf habit has been hypothesized to define a linkage between the slow-fast plant economic spectrum and the drought resistance-avoidance trade-off in tropical forests ('slow-safe vs fast-risky'). However, variation in hydraulic traits as a function of leaf habit has rarely been explored for a large number of species. We sampled leaf and branch functional traits of 97 tropical dry forest tree species from four sites to investigate whether patterns of trait variation varied consistently in relation to leaf habit along the 'slow-safe vs fast-risky' trade-off. Leaf habit explained from 0% to 43.69% of individual trait variation. We found that evergreen and semi-deciduous species differed in their location along the multivariate trait ordination when compared to deciduous species. While deciduous species showed consistent trait values, evergreen species trait values varied as a function of the site. Last, trait values varied in relation to the proportion of deciduous species in the plant community. We found that leaf habit describes the strategies that define drought avoidance and plant economics in tropical trees. However, leaf habit alone does not explain patterns of trait variation, which suggests quantifying site-specific or species-specific uncertainty in trait variation as the way forward.
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Affiliation(s)
- German Vargas G
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Juan M Dupuy
- Centro de Investigación Científica de Yucatán, Unidad de Recursos Naturales, Calle 43 # 130 entre 32 y 34, Col. Chuburná de Hidalgo, Mérida, Yucatán, CP 97205, México
| | - Roy González-M
- Programa Ciencias de la Biodiversidad, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Carrera #1 16-20, Bogotá, 111311, Colombia
| | - Catherine M Hulshof
- Department of Biology, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - David Medvigy
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Tristan A P Allerton
- Baruch Institute of Coastal Ecology and Forest Science, Clemson University, PO Box 596, Georgetown, SC, 29442, USA
| | - Camila Pizano
- Departamento de Biología, Universidad ICESI, Calle 18 # 122-135, Cali, 760031, Colombia
| | - Beatriz Salgado-Negret
- Departamento de Biología, Universidad Nacional de Colombia, sede Bogotá, Carrera 30 Calle 45, Bogotá, 111321, Colombia
| | - Naomi B Schwartz
- Department of Geography, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
| | - Skip J Van Bloem
- Baruch Institute of Coastal Ecology and Forest Science, Clemson University, PO Box 596, Georgetown, SC, 29442, USA
| | - Bonnie G Waring
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Jennifer S Powers
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA
- Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN, 55108, USA
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8
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Harrison SP, Cramer W, Franklin O, Prentice IC, Wang H, Brännström Å, de Boer H, Dieckmann U, Joshi J, Keenan TF, Lavergne A, Manzoni S, Mengoli G, Morfopoulos C, Peñuelas J, Pietsch S, Rebel KT, Ryu Y, Smith NG, Stocker BD, Wright IJ. Eco-evolutionary optimality as a means to improve vegetation and land-surface models. THE NEW PHYTOLOGIST 2021; 231:2125-2141. [PMID: 34131932 DOI: 10.1111/nph.17558] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
Global vegetation and land-surface models embody interdisciplinary scientific understanding of the behaviour of plants and ecosystems, and are indispensable to project the impacts of environmental change on vegetation and the interactions between vegetation and climate. However, systematic errors and persistently large differences among carbon and water cycle projections by different models highlight the limitations of current process formulations. In this review, focusing on core plant functions in the terrestrial carbon and water cycles, we show how unifying hypotheses derived from eco-evolutionary optimality (EEO) principles can provide novel, parameter-sparse representations of plant and vegetation processes. We present case studies that demonstrate how EEO generates parsimonious representations of core, leaf-level processes that are individually testable and supported by evidence. EEO approaches to photosynthesis and primary production, dark respiration and stomatal behaviour are ripe for implementation in global models. EEO approaches to other important traits, including the leaf economics spectrum and applications of EEO at the community level are active research areas. Independently tested modules emerging from EEO studies could profitably be integrated into modelling frameworks that account for the multiple time scales on which plants and plant communities adjust to environmental change.
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Affiliation(s)
- Sandy P Harrison
- Department of Geography and Environmental Science, University of Reading, Reading, RG6 6AB, UK
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, 100084, China
| | - Wolfgang Cramer
- Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale, Aix Marseille Université, CNRS, IRD, Avignon Université, Technopôle Arbois-Méditerranée, Aix-en-Provence Cedex 04, F-13545, France
| | - Oskar Franklin
- International Institute for Applied Systems Analysis, Schlossplatz 1, Laxenburg, 2361, Austria
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, 90183, Sweden
| | - Iain Colin Prentice
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, 100084, China
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Han Wang
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, 100084, China
| | - Åke Brännström
- International Institute for Applied Systems Analysis, Schlossplatz 1, Laxenburg, 2361, Austria
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, 901 87, Sweden
| | - Hugo de Boer
- Copernicus Institute of Sustainable Development, Environmental Sciences, Faculty of Geosciences, Utrecht University, Vening Meinesz Building, Princetonlaan 8a, Utrecht, 3584 CB, the Netherlands
| | - Ulf Dieckmann
- International Institute for Applied Systems Analysis, Schlossplatz 1, Laxenburg, 2361, Austria
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, 240-0193, Japan
| | - Jaideep Joshi
- International Institute for Applied Systems Analysis, Schlossplatz 1, Laxenburg, 2361, Austria
| | - Trevor F Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Aliénor Lavergne
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Stefano Manzoni
- Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Giulia Mengoli
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK
| | - Catherine Morfopoulos
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK
| | - Josep Peñuelas
- CSIC, Global Ecology, CREAF-CSIC-UAB, Bellaterra, Barcelona, Catalonia, 08193, Spain
- CREAF, Cerdanyola del Valles, Barcelona, Catalonia, 08193, Spain
| | - Stephan Pietsch
- International Institute for Applied Systems Analysis, Schlossplatz 1, Laxenburg, 2361, Austria
- BOKU - University of Life Sciences and Natural Resources, Gregor-Medel-Strasse 33, Vienna, 1180, Austria
| | - Karin T Rebel
- Copernicus Institute of Sustainable Development, Environmental Sciences, Faculty of Geosciences, Utrecht University, Vening Meinesz Building, Princetonlaan 8a, Utrecht, 3584 CB, the Netherlands
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Nicholas G Smith
- Department of Biological Sciences, Texas Tech University, 2901 Main Street, Lubbock, TX, 79409, USA
| | - Benjamin D Stocker
- Department of Environmental System Science, ETH, Universitätstrasse 2, Zürich, CH-8092, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zrcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
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9
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Effects of Throughfall Exclusion on Photosynthetic Traits in Mature Japanese Cedar (Cryptomeria japonica (L. f.) D. Don.). FORESTS 2021. [DOI: 10.3390/f12080971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
As climate change progresses, it is becoming more crucial to understand how timber species respond to increased drought frequency and severity. Photosynthetic traits in a 40-year-old clonal Japanese cedar (Cryptomeria japonica) plantation were assessed under artificial drought stress using a roof to exclude rainfall and a control with no exclusion. C. japonica is a commercial tree that is native to Japan and has high growth on mesic sites. The maximum carboxylation rate (Vcmax), maximum electron transfer rate (Jmax), and dark respiration rate (Rd) in current-year shoots in the upper canopy were determined from spring to autumn over two growing seasons. In addition, the photosynthetic rate at light saturation (Pmax), stomatal conductance (gs), and intrinsic water use efficiency (WUEi) were measured in the morning and afternoon during the same period. Leaf mass per unit area (LMA) and nitrogen concentration (N) were also measured. The values of Vcmax, Jmax, Rd, N, and LMA did not differ between the two plots. By contrast, significantly lower Pmax and gs and higher WUEi were found in the drought plot, and the reduction in Pmax was accompanied by low gs values. Midday depressions in Pmax and gs were more pronounced in the drought plot relative to the control and were related to higher WUEi. Under drought conditions, mature Japanese cedar experienced little change in photosynthetic capacity, foliar N, or LMA, but they did tend to close the stomata to regulate transpiration, thus avoiding drought-induced damage to the photosynthetic machinery and improving WUEi.
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10
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Aranda I, Cadahía E, Fernández de Simón B. Specific leaf metabolic changes that underlie adjustment of osmotic potential in response to drought by four Quercus species. TREE PHYSIOLOGY 2021; 41:728-743. [PMID: 33231684 DOI: 10.1093/treephys/tpaa157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/11/2020] [Indexed: 05/14/2023]
Abstract
Osmotic adjustment is almost ubiquitous as a mechanism of response to drought in many forest species. Recognized as an important mechanism of increasing turgor under water stress, the metabolic basis for osmotic adjustment has been described in only a few species. We set an experiment with four species of the genus Quercus ranked according to drought tolerance and leaf habit from evergreen to broad-leaved deciduous. A cycle of watering deprivation was imposed on seedlings, resulting in well-watered (WW) and water-stressed (WS) treatments, and their water relations were assessed from pressure-volume curves. Leaf predawn water potential (Ψpd) significantly decreased in WS seedlings, which was followed by a drop in leaf osmotic potential at full turgor (Ψπ100). The lowest values of Ψπ100 followed the ranking of decreasing drought tolerance: Quercus ilex L. < Quercus faginea Lam. < Quercus pyrenaica Willd. < Quercus petraea Matt. Liebl. The leaf osmotic potential at the turgor loss point (ΨTLP) followed the same pattern as Ψπ100 across species and treatments. The pool of carbohydrates, some organic acids and cyclitols were the main osmolytes explaining osmotic potential across species, likewise to the osmotic adjustment assessed from the decrease in leaf Ψπ100 between WW and WS seedlings. Amino acids were very responsive to WS, particularly γ-aminobutyric acid in Q. pyrenaica, but made a relatively minor contribution to osmotic potential compared with other groups of compounds. In contrast, the cyclitol proto-quercitol made a prominent contribution to the changes in osmotic potential regardless of watering treatment or species. However, different metabolites, such as quinic acid, played a more important role in osmotic adjustment in Q. ilex, distinguishing it from the other species studied. In conclusion, while osmotic adjustment was present in all four Quercus species, the molecular processes underpinning this response differed according to their phylogenetic history and specific ecology.
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Affiliation(s)
- Ismael Aranda
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
- INAGEA, Instituto de Investigaciones Agroambientales y de Economía del Agua, 07122 Palma de Mallorca, Spain
| | - Estrella Cadahía
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
| | - Brígida Fernández de Simón
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
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11
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Milligan PD, Martin TA, John GP, Riginos C, Goheen JR, Carpenter SM, Palmer TM. Mutualism disruption by an invasive ant reduces carbon fixation for a foundational East African ant-plant. Ecol Lett 2021; 24:1052-1062. [PMID: 33745197 DOI: 10.1111/ele.13725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 11/30/2022]
Abstract
Invasive ants shape assemblages and interactions of native species, but their effect on fundamental ecological processes is poorly understood. In East Africa, Pheidole megacephala ants have invaded monodominant stands of the ant-tree Acacia drepanolobium, extirpating native ant defenders and rendering trees vulnerable to canopy damage by vertebrate herbivores. We used experiments and observations to quantify direct and interactive effects of invasive ants and large herbivores on A. drepanolobium photosynthesis over a 2-year period. Trees that had been invaded for ≥ 5 years exhibited 69% lower whole-tree photosynthesis during key growing seasons, resulting from interaction between invasive ants and vertebrate herbivores that caused leaf- and canopy-level photosynthesis declines. We also surveyed trees shortly before and after invasion, finding that recent invasion induced only minor changes in leaf physiology. Our results from individual trees likely scale up, highlighting the potential of invasive species to alter ecosystem-level carbon fixation and other biogeochemical cycles.
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Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
| | - Timothy A Martin
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL, USA
| | | | - Jacob R Goheen
- Mpala Research Centre, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | | | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
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12
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Bittencourt PRL, Oliveira RS, da Costa ACL, Giles AL, Coughlin I, Costa PB, Bartholomew DC, Ferreira LV, Vasconcelos SS, Barros FV, Junior JAS, Oliveira AAR, Mencuccini M, Meir P, Rowland L. Amazonia trees have limited capacity to acclimate plant hydraulic properties in response to long-term drought. GLOBAL CHANGE BIOLOGY 2020; 26:3569-3584. [PMID: 32061003 DOI: 10.1111/gcb.15040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/30/2019] [Accepted: 02/02/2020] [Indexed: 05/29/2023]
Abstract
The fate of tropical forests under future climate change is dependent on the capacity of their trees to adjust to drier conditions. The capacity of trees to withstand drought is likely to be determined by traits associated with their hydraulic systems. However, data on whether tropical trees can adjust hydraulic traits when experiencing drought remain rare. We measured plant hydraulic traits (e.g. hydraulic conductivity and embolism resistance) and plant hydraulic system status (e.g. leaf water potential, native embolism and safety margin) on >150 trees from 12 genera (36 species) and spanning a stem size range from 14 to 68 cm diameter at breast height at the world's only long-running tropical forest drought experiment. Hydraulic traits showed no adjustment following 15 years of experimentally imposed moisture deficit. This failure to adjust resulted in these drought-stressed trees experiencing significantly lower leaf water potentials, and higher, but variable, levels of native embolism in the branches. This result suggests that hydraulic damage caused by elevated levels of embolism is likely to be one of the key drivers of drought-induced mortality following long-term soil moisture deficit. We demonstrate that some hydraulic traits changed with tree size, however, the direction and magnitude of the change was controlled by taxonomic identity. Our results suggest that Amazonian trees, both small and large, have limited capacity to acclimate their hydraulic systems to future droughts, potentially making them more at risk of drought-induced mortality.
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Affiliation(s)
- Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
- Biological Sciences, UWA, Perth, WA, Australia
| | | | - Andre L Giles
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Ingrid Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Patricia B Costa
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
- Biological Sciences, UWA, Perth, WA, Australia
| | - David C Bartholomew
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Fernanda V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Joao A S Junior
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, ACT, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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13
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Yoshifuji N, Kumagai T, Ichie T, Kume T, Tateishi M, Inoue Y, Yoneyama A, Nakashizuka T. Limited stomatal regulation of the largest-size class of Dryobalanops aromatica in a Bornean tropical rainforest in response to artificial soil moisture reduction. JOURNAL OF PLANT RESEARCH 2020; 133:175-191. [PMID: 31858360 DOI: 10.1007/s10265-019-01161-3] [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: 04/05/2019] [Accepted: 12/08/2019] [Indexed: 06/10/2023]
Abstract
The physiological response of trees to drought is crucial for understanding the risk of mortality and its feedbacks to climate under the increase in droughts due to climate change, especially for the largest trees in tropical rainforests because of their large contribution to total carbon storage and water use. We determined the response of the mean canopy stomatal conductance per unit leaf area (gs) and whole-tree hydraulic conductance (Gp) of the largest individuals (38-53 m in height) of a typical canopy tree species in a Bornean tropical rainforest, Dryobalanops aromatica C.F.Gaertn., to soil moisture reduction by a 4-month rainfall exclusion experiment (REE) based on the measurements of sap flux and leaf water potentials at midday and dawn. In the mesic condition, the gs at vapor pressure deficit (D) = 1 kPa (gsref) was small compared with the reported values in various biomes. The sensitivity of gs to D (m) at a given gsref (m/gsref) was ≥ 0.6 irrespective of soil moisture conditions, indicating intrinsically sensitive stomatal control with increasing D. The REE caused greater soil drought and decreased the mean leaf water potentials at midday and dawn to the more negative values than the control under the relatively dry conditions due to natural reduction in rainfall. However, the REE did not cause a greater decrease in gs nor any clear alteration in the sensitivity of gs to D compared with the control, and induced greater decreases in Gp during REE than the control. Thus, though the small gs and the sensitive stomatal response to D indicate the water saving characteristics of the studied trees under usual mesic conditions, their limited stomatal regulation in response to soil drought by REE and the resulting decline in Gp might suggest a poor resistance to the unusually severe drought expected in the future.
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Affiliation(s)
- Natsuko Yoshifuji
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
- Kasuya Research Forest, Kyushu University, Sasaguri, Fukuoka, 811-2415, Japan.
| | - Tomo'omi Kumagai
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Aichi, 464-8601, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Tomoaki Ichie
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, 783-8502, Japan
| | - Tomonori Kume
- Kasuya Research Forest, Kyushu University, Sasaguri, Fukuoka, 811-2415, Japan
| | - Makiko Tateishi
- Kyoto University Research Administration Office, Kyoto, 606-8501, Japan
| | - Yuta Inoue
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime, 790-8566, Japan
| | - Aogu Yoneyama
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, 783-8502, Japan
| | - Tohru Nakashizuka
- Research Institute for Humanity and Nature, Kamigamo-Motoyama, Kyoto, 603-8047, Japan
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14
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Tang ACI, Stoy PC, Hirata R, Musin KK, Aeries EB, Wenceslaus J, Shimizu M, Melling L. The exchange of water and energy between a tropical peat forest and the atmosphere: Seasonal trends and comparison against other tropical rainforests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 683:166-174. [PMID: 31132697 DOI: 10.1016/j.scitotenv.2019.05.217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 06/09/2023]
Abstract
Tropical rainforests control the exchange of water and energy between the land surface and the atmosphere near the equator and thus play an important role in the global climate system. Measurements of latent (LE) and sensible heat exchange (H) have not been synthesized across global tropical rainforests to date, which can help place observations from individual tropical forests in a global context. We measured LE and H for four years in a tropical peat forest ecosystem in Sarawak, Malaysian Borneo using eddy covariance, and hypothesize that the study ecosystem will exhibit less seasonal variability in turbulent fluxes than other tropical ecosystems as soil water is not expected to be limiting in a tropical forested wetland. LE and H show little variability across seasons in the study ecosystem, with LE values on the order of 11 MJ m-2 day and H on the order of 3 MJ m-2 day-1. Annual evapotranspiration (ET) did not differ among years and averaged 1579 ± 47 mm year-1. LE exceeded characteristic values from other tropical rainforest ecosystems in the FLUXNET2015 database with the exception of GF-Guy near coastal French Guyana, which averaged 8-11 MJ m-2 day-1. The Bowen ratio (Bo) in tropical rainforests in the FLUXNET2015 database either exhibited little seasonal trend, one seasonal peak, or two peaks. Volumetric water content (VWC) and VPD explained a trivial amount of the variability of LE and Bo in some of the tropical rainforests including the study ecosystem, but were strong controls in others, suggesting differences in stomatal regulation and/or the partitioning between evaporation and transpiration. Results demonstrate important differences in the seasonal patterns in water and energy exchange across different tropical rainforest ecosystems that need to be understood to quantify how ongoing changes in tropical rainforest extent will impact the global climate system.
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Affiliation(s)
- Angela C I Tang
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA; Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Paul C Stoy
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA.
| | - Ryuichi Hirata
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
| | - Kevin K Musin
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Edward B Aeries
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Joseph Wenceslaus
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Mariko Shimizu
- Civil Engineering Research Institute for Cold Region, Sapporo 062-8602, Japan
| | - Lulie Melling
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
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15
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Tng DYP, Apgaua DMG, Ishida YF, Mencuccini M, Lloyd J, Laurance WF, Laurance SGW. Rainforest trees respond to drought by modifying their hydraulic architecture. Ecol Evol 2018; 8:12479-12491. [PMID: 30619559 PMCID: PMC6308889 DOI: 10.1002/ece3.4601] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 02/06/2023] Open
Abstract
Increased drought is forecasted for tropical regions, with severe implications for the health and function of forest ecosystems. How mature forest trees will respond to water deficit is poorly known. We investigated wood anatomy and leaf traits in lowland tropical forest trees after 24 months of experimental rainfall exclusion. Sampling sun-exposed young canopy branches from target species, we found species-specific systematic variation in hydraulic-related wood anatomy and leaf traits in response to drought stress. Relative to controls, drought-affected individuals of different tree species variously exhibited trait measures consistent with increasing hydraulic safety. These included narrower or less vessels, reduced vessel groupings, lower theoretical water conductivities, less water storage tissue and more abundant fiber in their wood, and more occluded vessels. Drought-affected individuals also had thinner leaves, and more negative pre-dawn or mid-day leaf water potentials. Future studies examining both wood and leaf hydraulic traits should improve the representation of plant hydraulics within terrestrial ecosystem and biosphere models, and help fine-tune predictions of how future climate changes will affect tropical forests globally.
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Affiliation(s)
- David Y. P. Tng
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Instituto de BiologiaUniversidade Federal da BahiaSalvadorBahiaBrazil
| | - Deborah M. G. Apgaua
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Yoko F. Ishida
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Maurizio Mencuccini
- ICREAPg. Lluís CompanysBarcelonaSpain
- CREAFUniversidad Autonoma de BarcelonaBarcelonaSpain
| | - Jon Lloyd
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Department of Life SciencesImperial College LondonAscotUK
- Faculdade de Filosofia, Ciencias e Letras de Ribeirao PretoUniversidade de Sao PauloRibeirao PretoBrazil
| | - William F. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Susan G. W. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
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16
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Meir P, Mencuccini M, Binks O, da Costa AL, Ferreira L, Rowland L. Short-term effects of drought on tropical forest do not fully predict impacts of repeated or long-term drought: gas exchange versus growth. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170311. [PMID: 30297468 PMCID: PMC6178433 DOI: 10.1098/rstb.2017.0311] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2018] [Indexed: 11/12/2022] Open
Abstract
Are short-term responses by tropical rainforest to drought (e.g. during El Niño) sufficient to predict changes over the long-term, or from repeated drought? Using the world's only long-term (16-year) drought experiment in tropical forest we examine predictability from short-term measurements (1-2 years). Transpiration was maximized in droughted forest: it consumed all available throughfall throughout the 16 years of study. Leaf photosynthetic capacity [Formula: see text] was maintained, but only when averaged across tree size groups. Annual transpiration in droughted forest was less than in control, with initial reductions (at high biomass) imposed by foliar stomatal control. Tree mortality increased after year three, leading to an overall biomass loss of 40%; over the long-term, the main constraint on transpiration was thus imposed by the associated reduction in sapwood area. Altered tree mortality risk may prove predictable from soil and plant hydraulics, but additional monitoring is needed to test whether future biomass will stabilize or collapse. Allocation of assimilate differed over time: stem growth and reproductive output declined in the short-term, but following mortality-related changes in resource availability, both showed long-term resilience, with partial or full recovery. Understanding and simulation of these phenomena and related trade-offs in allocation will advance more effectively through greater use of optimization and probabilistic modelling approaches.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- School of Geosciences, University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3FF, UK
| | - Maurizio Mencuccini
- CREAF, Campus UAB, Cerdanyola del Vallés 08193, Spain
- ICREA, Barcelona 08193, Spain
| | - Oliver Binks
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Antonio Lola da Costa
- Instituto de Geosciências, Universidade Federal do Pará, Belém, PA 66075-110, Brazil
| | | | - Lucy Rowland
- Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Exeter EX4 4RJ, UK
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17
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Santos VAHFD, Ferreira MJ, Rodrigues JVFC, Garcia MN, Ceron JVB, Nelson BW, Saleska SR. Causes of reduced leaf-level photosynthesis during strong El Niño drought in a Central Amazon forest. GLOBAL CHANGE BIOLOGY 2018; 24:4266-4279. [PMID: 29723915 DOI: 10.1111/gcb.14293] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 03/18/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Sustained drought and concomitant high temperature may reduce photosynthesis and cause tree mortality. Possible causes of reduced photosynthesis include stomatal closure and biochemical inhibition, but their relative roles are unknown in Amazon trees during strong drought events. We assessed the effects of the recent (2015) strong El Niño drought on leaf-level photosynthesis of Central Amazon trees via these two mechanisms. Through four seasons of 2015, we measured leaf gas exchange, chlorophyll a fluorescence parameters, chlorophyll concentration, and nutrient content in leaves of 57 upper canopy and understory trees of a lowland terra firme forest on well-drained infertile oxisol. Photosynthesis decreased 28% in the upper canopy and 17% in understory trees during the extreme dry season of 2015, relative to other 2015 seasons and was also lower than the climatically normal dry season of the following non-El Niño year. Photosynthesis reduction under extreme drought and high temperature in the 2015 dry season was related only to stomatal closure in both upper canopy and understory trees, and not to chlorophyll a fluorescence parameters, chlorophyll, or leaf nutrient concentration. The distinction is important because stomatal closure is a transient regulatory response that can reverse when water becomes available, whereas the other responses reflect more permanent changes or damage to the photosynthetic apparatus. Photosynthesis decrease due to stomatal closure during the 2015 extreme dry season was followed 2 months later by an increase in photosynthesis as rains returned, indicating a margin of resilience to one-off extreme climatic events in Amazonian forests.
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Affiliation(s)
| | | | | | - Maquelle Neves Garcia
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - João Vitor Barbosa Ceron
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - Bruce Walker Nelson
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - Scott Reid Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona
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