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Luo X, Zhou H, Satriawan TW, Tian J, Zhao R, Keenan TF, Griffith DM, Sitch S, Smith NG, Still CJ. Mapping the global distribution of C 4 vegetation using observations and optimality theory. Nat Commun 2024; 15:1219. [PMID: 38336770 PMCID: PMC10858286 DOI: 10.1038/s41467-024-45606-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Plants with the C4 photosynthesis pathway typically respond to climate change differently from more common C3-type plants, due to their distinct anatomical and biochemical characteristics. These different responses are expected to drive changes in global C4 and C3 vegetation distributions. However, current C4 vegetation distribution models may not predict this response as they do not capture multiple interacting factors and often lack observational constraints. Here, we used global observations of plant photosynthetic pathways, satellite remote sensing, and photosynthetic optimality theory to produce an observation-constrained global map of C4 vegetation. We find that global C4 vegetation coverage decreased from 17.7% to 17.1% of the land surface during 2001 to 2019. This was the net result of a reduction in C4 natural grass cover due to elevated CO2 favoring C3-type photosynthesis, and an increase in C4 crop cover, mainly from corn (maize) expansion. Using an emergent constraint approach, we estimated that C4 vegetation contributed 19.5% of global photosynthetic carbon assimilation, a value within the range of previous estimates (18-23%) but higher than the ensemble mean of dynamic global vegetation models (14 ± 13%; mean ± one standard deviation). Our study sheds insight on the critical and underappreciated role of C4 plants in the contemporary global carbon cycle.
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Affiliation(s)
- Xiangzhong Luo
- Department of Geography, National University of Singapore, Singapore, Singapore.
- Center for Nature-based Climate Solutions, National University of Singapore, Singapore, Singapore.
| | - Haoran Zhou
- School of Earth System Science, Institute of Surface-Earth System Science, Tianjin University, Tianjin, China.
| | - Tin W Satriawan
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Jiaqi Tian
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Ruiying Zhao
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Trevor F Keenan
- Department of Ecosystem Sciences, Policy and Management, UC Berkeley, Berkeley, CA, USA
- Earth and Environmental Sciences Area, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - Daniel M Griffith
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, USA
| | - Stephen Sitch
- Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Nicholas G Smith
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Christopher J Still
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, USA
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2
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Wilcox KR, Chen A, Avolio ML, Butler EE, Collins S, Fisher R, Keenan T, Kiang NY, Knapp AK, Koerner SE, Kueppers L, Liang G, Lieungh E, Loik M, Luo Y, Poulter B, Reich P, Renwick K, Smith MD, Walker A, Weng E, Komatsu KJ. Accounting for herbaceous communities in process-based models will advance our understanding of "grassy" ecosystems. GLOBAL CHANGE BIOLOGY 2023; 29:6453-6477. [PMID: 37814910 DOI: 10.1111/gcb.16950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/01/2023] [Indexed: 10/11/2023]
Abstract
Grassland and other herbaceous communities cover significant portions of Earth's terrestrial surface and provide many critical services, such as carbon sequestration, wildlife habitat, and food production. Forecasts of global change impacts on these services will require predictive tools, such as process-based dynamic vegetation models. Yet, model representation of herbaceous communities and ecosystems lags substantially behind that of tree communities and forests. The limited representation of herbaceous communities within models arises from two important knowledge gaps: first, our empirical understanding of the principles governing herbaceous vegetation dynamics is either incomplete or does not provide mechanistic information necessary to drive herbaceous community processes with models; second, current model structure and parameterization of grass and other herbaceous plant functional types limits the ability of models to predict outcomes of competition and growth for herbaceous vegetation. In this review, we provide direction for addressing these gaps by: (1) presenting a brief history of how vegetation dynamics have been developed and incorporated into earth system models, (2) reporting on a model simulation activity to evaluate current model capability to represent herbaceous vegetation dynamics and ecosystem function, and (3) detailing several ecological properties and phenomena that should be a focus for both empiricists and modelers to improve representation of herbaceous vegetation in models. Together, empiricists and modelers can improve representation of herbaceous ecosystem processes within models. In so doing, we will greatly enhance our ability to forecast future states of the earth system, which is of high importance given the rapid rate of environmental change on our planet.
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Affiliation(s)
- Kevin R Wilcox
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
- University of Wyoming, Laramie, Wyoming, USA
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Meghan L Avolio
- Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ethan E Butler
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Scott Collins
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Rosie Fisher
- CICERO Centre for International Cimate Research, Forskningsparken, Oslo, Norway
| | - Trevor Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy Y Kiang
- NASA Goddard Institute for Space Studies, New York, New York, USA
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Sally E Koerner
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
| | - Lara Kueppers
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Guopeng Liang
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Eva Lieungh
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Michael Loik
- Department of Environmental Studies, University of California, Santa Cruz, California, USA
| | - Yiqi Luo
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Ben Poulter
- Biospheric Sciences Lab, NASA GSFC, Greenbelt, Maryland, USA
| | - Peter Reich
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Melinda D Smith
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Anthony Walker
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Ensheng Weng
- NASA Goddard Institute for Space Studies, New York, New York, USA
- Center for Climate Systems Research, Columbia University, New York, New York, USA
| | - Kimberly J Komatsu
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
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3
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Peppe DJ, Cote SM, Deino AL, Fox DL, Kingston JD, Kinyanjui RN, Lukens WE, MacLatchy LM, Novello A, Strömberg CAE, Driese SG, Garrett ND, Hillis KR, Jacobs BF, Jenkins KEH, Kityo RM, Lehmann T, Manthi FK, Mbua EN, Michel LA, Miller ER, Mugume AAT, Muteti SN, Nengo IO, Oginga KO, Phelps SR, Polissar P, Rossie JB, Stevens NJ, Uno KT, McNulty KP. Oldest evidence of abundant C 4 grasses and habitat heterogeneity in eastern Africa. Science 2023; 380:173-177. [PMID: 37053309 DOI: 10.1126/science.abq2834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The assembly of Africa's iconic C4 grassland ecosystems is central to evolutionary interpretations of many mammal lineages, including hominins. C4 grasses are thought to have become ecologically dominant in Africa only after 10 million years ago (Ma). However, paleobotanical records older than 10 Ma are sparse, limiting assessment of the timing and nature of C4 biomass expansion. This study uses a multiproxy design to document vegetation structure from nine Early Miocene mammal site complexes across eastern Africa. Results demonstrate that between ~21 and 16 Ma, C4 grasses were locally abundant, contributing to heterogeneous habitats ranging from forests to wooded grasslands. These data push back the oldest evidence of C4 grass-dominated habitats in Africa-and globally-by more than 10 million years, calling for revised paleoecological interpretations of mammalian evolution.
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Affiliation(s)
- Daniel J Peppe
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
| | - Susanne M Cote
- Department of Anthropology and Archaeology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Alan L Deino
- Berkeley Geochronology Center, Berkeley, CA 94709, USA
| | - David L Fox
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - John D Kingston
- Department of Anthropology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rahab N Kinyanjui
- Department of Earth Sciences, National Museums of Kenya, Nairobi 00100, Kenya
- Max Planck Institute for Geoanthropology, D-07743 Jena, Germany
- Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
| | - William E Lukens
- Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA 22807, USA
| | - Laura M MacLatchy
- Department of Anthropology, University of Michigan, Ann Arbor, MI 48109, USA
- Museum of Paleontology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alice Novello
- CEREGE, Aix-Marseille Université, CNRS, IRD, Collège de France, INRAE, 13545 Aix en Provence, France
- Department of Biology, Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195, USA
| | - Caroline A E Strömberg
- Department of Biology, Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195, USA
| | - Steven G Driese
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
| | - Nicole D Garrett
- Department of Anthropology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kayla R Hillis
- Department of Earth Sciences, Tennessee Tech University, Cookeville, TN 38505, USA
| | - Bonnie F Jacobs
- Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | - Kirsten E H Jenkins
- Department of Social Sciences, Tacoma Community College, Tacoma, WA 98466, USA
| | - Robert M Kityo
- Department of Zoology Entomology and Fisheries Sciences, Makerere University, Kampala, Uganda
| | - Thomas Lehmann
- Department Messel Research and Mammalogy, Senckenberg Research Institute and Natural History Museum, 60325 Frankfurt, Germany
| | - Fredrick K Manthi
- Department of Earth Sciences, National Museums of Kenya, Nairobi 00100, Kenya
| | - Emma N Mbua
- Department of Earth Sciences, National Museums of Kenya, Nairobi 00100, Kenya
| | - Lauren A Michel
- Department of Earth Sciences, Tennessee Tech University, Cookeville, TN 38505, USA
| | - Ellen R Miller
- Department of Anthropology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Amon A T Mugume
- Department of Zoology Entomology and Fisheries Sciences, Makerere University, Kampala, Uganda
- Uganda National Museum, Department of Museums and Monuments, Ministry of Tourism, Wildlife and Antiquities, Kampala, Uganda
| | - Samuel N Muteti
- Department of Earth Sciences, National Museums of Kenya, Nairobi 00100, Kenya
- Department of Anthropology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Isaiah O Nengo
- Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794, USA
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Kennedy O Oginga
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
| | - Samuel R Phelps
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Pratigya Polissar
- Ocean Sciences Department, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - James B Rossie
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Nancy J Stevens
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH 45701, USA
| | - Kevin T Uno
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA
| | - Kieran P McNulty
- Department of Anthropology, University of Minnesota, Minneapolis, MN 55455, USA
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Andermann T, Strömberg CAE, Antonelli A, Silvestro D. The origin and evolution of open habitats in North America inferred by Bayesian deep learning models. Nat Commun 2022; 13:4833. [PMID: 35977931 PMCID: PMC9385654 DOI: 10.1038/s41467-022-32300-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 07/25/2022] [Indexed: 11/21/2022] Open
Abstract
Some of the most extensive terrestrial biomes today consist of open vegetation, including temperate grasslands and tropical savannas. These biomes originated relatively recently in Earth's history, likely replacing forested habitats in the second half of the Cenozoic. However, the timing of their origination and expansion remains disputed. Here, we present a Bayesian deep learning model that utilizes information from fossil evidence, geologic models, and paleoclimatic proxies to reconstruct paleovegetation, placing the emergence of open habitats in North America at around 23 million years ago. By the time of the onset of the Quaternary glacial cycles, open habitats were covering more than 30% of North America and were expanding at peak rates, to eventually become the most prominent natural vegetation type today. Our entirely data-driven approach demonstrates how deep learning can harness unexplored signals from complex data sets to provide insights into the evolution of Earth's biomes in time and space.
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Affiliation(s)
- Tobias Andermann
- Department of Organismal Biology, SciLifeLab, Uppsala University, Uppsala, Sweden.
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
- Gothenburg Global Biodiversity Centre, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
| | - Caroline A E Strömberg
- Department of Biology & Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Alexandre Antonelli
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Plant Sciences, University of Oxford, Oxford, UK
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | - Daniele Silvestro
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
- Gothenburg Global Biodiversity Centre, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
- Swiss Institute of Bioinformatics, Fribourg, Switzerland.
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5
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Griffith DM, Osborne CP, Edwards EJ, Bachle S, Beerling DJ, Bond WJ, Gallaher TJ, Helliker BR, Lehmann CER, Leatherman L, Nippert JB, Pau S, Qiu F, Riley WJ, Smith MD, Strömberg CAE, Taylor L, Ungerer M, Still CJ. Lineage-based functional types: characterising functional diversity to enhance the representation of ecological behaviour in Land Surface Models. THE NEW PHYTOLOGIST 2020; 228:15-23. [PMID: 33448428 DOI: 10.1111/nph.16773] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/28/2020] [Indexed: 06/12/2023]
Abstract
Process-based vegetation models attempt to represent the wide range of trait variation in biomes by grouping ecologically similar species into plant functional types (PFTs). This approach has been successful in representing many aspects of plant physiology and biophysics but struggles to capture biogeographic history and ecological dynamics that determine biome boundaries and plant distributions. Grass-dominated ecosystems are broadly distributed across all vegetated continents and harbour large functional diversity, yet most Land Surface Models (LSMs) summarise grasses into two generic PFTs based primarily on differences between temperate C3 grasses and (sub)tropical C4 grasses. Incorporation of species-level trait variation is an active area of research to enhance the ecological realism of PFTs, which form the basis for vegetation processes and dynamics in LSMs. Using reported measurements, we developed grass functional trait values (physiological, structural, biochemical, anatomical, phenological, and disturbance-related) of dominant lineages to improve LSM representations. Our method is fundamentally different from previous efforts, as it uses phylogenetic relatedness to create lineage-based functional types (LFTs), situated between species-level trait data and PFT-level abstractions, thus providing a realistic representation of functional diversity and opening the door to the development of new vegetation models.
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Affiliation(s)
- Daniel M Griffith
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
- US Geological Survey Western Geographic Science Center, Moffett Field, CA, 94035, USA
- NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
| | - Seton Bachle
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - William J Bond
- South African Environmental Observation Network, National Research Foundation, Claremont, 7735, South Africa
- Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Timothy J Gallaher
- Department of Biology and the Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, 98915, USA
- Bishop Museum, Honolulu, HI, 96817, USA
| | - Brent R Helliker
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19401, USA
| | | | - Lila Leatherman
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Jesse B Nippert
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Stephanie Pau
- Department of Geography, Florida State University, Tallahassee, FL, 32303, USA
| | - Fan Qiu
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - William J Riley
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Melinda D Smith
- Department of Biology, Colorado State University, Fort Collins, CO, 80521, USA
| | - Caroline A E Strömberg
- Department of Biology and the Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, 98915, USA
| | - Lyla Taylor
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Mark Ungerer
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
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6
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Resolving the Dust Bowl paradox of grassland responses to extreme drought. Proc Natl Acad Sci U S A 2020; 117:22249-22255. [PMID: 32839346 DOI: 10.1073/pnas.1922030117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During the 1930s Dust Bowl drought in the central United States, species with the C3 photosynthetic pathway expanded throughout C4-dominated grasslands. This widespread increase in C3 grasses during a decade of low rainfall and high temperatures is inconsistent with well-known traits of C3 vs. C4 pathways. Indeed, water use efficiency is generally lower, and photosynthesis is more sensitive to high temperatures in C3 than C4 species, consistent with the predominant distribution of C3 grasslands in cooler environments and at higher latitudes globally. We experimentally imposed extreme drought for 4 y in mixed C3/C4 grasslands in Kansas and Wyoming and, similar to Dust Bowl observations, also documented three- to fivefold increases in C3/C4 biomass ratios. To explain these paradoxical responses, we first analyzed long-term climate records to show that under nominal conditions in the central United States, C4 grasses dominate where precipitation and air temperature are strongly related (warmest months are wettest months). In contrast, C3 grasses flourish where precipitation inputs are less strongly coupled to warm temperatures. We then show that during extreme drought years, precipitation-temperature relationships weaken, and the proportion of precipitation falling during cooler months increases. This shift in precipitation seasonality provides a mechanism for C3 grasses to respond positively to multiyear drought, resolving the Dust Bowl paradox. Grasslands are globally important biomes and increasingly vulnerable to direct effects of climate extremes. Our findings highlight how extreme drought can indirectly alter precipitation seasonality and shift ecosystem phenology, affecting function in ways not predictable from key traits of C3 and C4 species.
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