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Bennett JJR, Bera BK, Ferré M, Yizhaq H, Getzin S, Meron E. Phenotypic plasticity: A missing element in the theory of vegetation pattern formation. Proc Natl Acad Sci U S A 2023; 120:e2311528120. [PMID: 38060562 PMCID: PMC10723140 DOI: 10.1073/pnas.2311528120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 11/06/2023] [Indexed: 12/17/2023] Open
Abstract
Regular spatial patterns of vegetation are a common sight in drylands. Their formation is a population-level response to water stress that increases water availability for the few via partial plant mortality. At the individual level, plants can also adapt to water stress by changing their phenotype. Phenotypic plasticity of individual plants and spatial patterning of plant populations have extensively been studied independently, but the likely interplay between the two robust mechanisms has remained unexplored. In this paper, we incorporate phenotypic plasticity into a multi-level theory of vegetation pattern formation and use a fascinating ecological phenomenon, the Namibian "fairy circles," to demonstrate the need for such a theory. We show that phenotypic changes in the root structure of plants, coupled with pattern-forming feedback within soil layers, can resolve two puzzles that the current theory fails to explain: observations of multi-scale patterns and the absence of theoretically predicted large-scale stripe and spot patterns along the rainfall gradient. Importantly, we find that multi-level responses to stress unveil a wide variety of more effective stress-relaxation pathways, compared to single-level responses, implying a previously underestimated resilience of dryland ecosystems.
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Affiliation(s)
- Jamie J. R. Bennett
- The Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Ben-Gurion8499000, Israel
| | - Bidesh K. Bera
- The Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Ben-Gurion8499000, Israel
| | - Michel Ferré
- The Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Ben-Gurion8499000, Israel
| | - Hezi Yizhaq
- The Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Ben-Gurion8499000, Israel
| | - Stephan Getzin
- Department of Ecosystem Modelling, University of Goettingen, Goettingen37073, Germany
| | - Ehud Meron
- The Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Midreshet Ben-Gurion8499000, Israel
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva8410501, Israel
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2
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Eppinga MB, Michaels TK, Santos MJ, Bever JD. Introducing desirable patches to initiate ecosystem transitions and accelerate ecosystem restoration. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2910. [PMID: 37602903 DOI: 10.1002/eap.2910] [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: 08/18/2022] [Revised: 05/30/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Meeting restoration targets may require active strategies to accelerate natural regeneration rates or overcome the resilience associated with degraded ecosystem states. Introducing desired ecosystem patches in degraded landscapes constitutes a promising active restoration strategy, with various mechanisms potentially causing these patches to become foci from which desired species can re-establish throughout the landscape. This study considers three mechanisms previously identified as potential drivers of introduced patch dynamics: autocatalytic nucleation, directed dispersal, and resource concentration. These mechanisms reflect qualitatively different positive feedbacks. We developed an ecological model framework that compared how the occurrence of each mechanism was reflected in spatio-temporal patch dynamics. We then analyzed the implications of these relationships for optimal restoration design. We found that patch expansion accelerated over time when driven by the autocatalytic nucleation mechanism, while patch expansion driven by the directed dispersal or resource concentration mechanisms decelerated over time. Additionally, when driven by autocatalytic nucleation, patch expansion was independent of patch position in the landscape. However, the proximity of other patches affected patch expansion either positively or negatively when driven by directed dispersal or resource concentration. For autocatalytic nucleation, introducing many small patches was a favorable strategy, provided that each individual patch exceeded a critical patch size. Introducing a single patch or a few large patches was the most effective restoration strategy to initiate the directed dispersal mechanism. Introducing many small patches was the most effective strategy for reaching restored ecosystem states driven by a resource concentration mechanism. Our model results suggest that introducing desirable patches can substantially accelerate ecosystem restoration, or even induce a critical transition from an otherwise stable degraded state toward a desired ecosystem state. However, the potential of this type of restoration strategy for a particular ecosystem may strongly depend on the mechanism driving patch dynamics. In turn, which mechanism drives patch dynamics may affect the optimal spatial design of an active restoration strategy. Each of the three mechanisms considered reflects distinct spatio-temporal patch dynamics, providing novel opportunities for empirically identifying key mechanisms, and restoration designs that introduce desired patches in degraded landscapes according to these patch dynamics.
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Affiliation(s)
| | - Theo K Michaels
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, USA
| | - Maria J Santos
- Department of Geography, University of Zurich, Zurich, Switzerland
| | - James D Bever
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, USA
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3
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Pal MK, Poria S. Role of herbivory in shaping the dryland vegetation ecosystem: Linking spiral vegetation patterns and nonlinear, nonlocal grazing. Phys Rev E 2023; 107:064403. [PMID: 37464659 DOI: 10.1103/physreve.107.064403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 04/17/2023] [Indexed: 07/20/2023]
Abstract
Self-organized vegetation patterns are an amazing aspect of dryland ecosystems; in addition to being visually appealing, patterns control how these water-deprived systems react to escalating environmental stress. Although there is a wide variety of vegetation patterns, little is known about the mechanisms behind spiral patterns. The well-known models that explain other vegetation patterns such stripes, rings, and fairy circles cannot account for these spirals. Here we have adopted a modeling approach in which the interplay between herbivore grazing and vegetation is found to be the reason why spirals form. To comprehend the nonlinear dependence of grazing on the availability vegetation, we have introduced a grazing term that gets saturated when forage is abundant. To account for the impact of the spatial nonhomogeneity in vegetation layout, it is thought that grazing is dependent on mean vegetation density rather than density at a single site. Results show how the system dynamics is changed fundamentally depending on the different types of grazing response. Incorporation of nonlocality into the herbivore grazing leads to spiral-shaped vegetation patterns only in natural grazing scenarios; however, no patterning is seen in human controlled herbivory. Overall, our research points to the nonlocal, nonlinear grazing behavior of herbivores as one of the major driving forces for the development of spiral patterns.
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Affiliation(s)
- Mrinal Kanti Pal
- Department of Applied Mathematics, University of Calcutta, 92 APC Road, Kolkata-700009, India
| | - Swarup Poria
- Department of Applied Mathematics, University of Calcutta, 92 APC Road, Kolkata-700009, India
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4
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Losapio G, Genes L, Knight CJ, McFadden TN, Pavan L. Monitoring and modelling the effects of ecosystem engineers on ecosystem functioning. Funct Ecol 2023. [DOI: 10.1111/1365-2435.14315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Gianalberto Losapio
- Department of Biology Stanford University Stanford California USA
- Institute of Earth Surface Dynamics, University of Lausanne Lausanne Switzerland
- Department of Biosciences University of Milan Milan Italy
| | - Luísa Genes
- Department of Biology Stanford University Stanford California USA
| | | | - Tyler N. McFadden
- Department of Biology Stanford University Stanford California USA
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USA
| | - Lucas Pavan
- Department of Biology Stanford University Stanford California USA
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5
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Bennett JJR, Gomes AS, Ferré MA, Bera BK, Borghetti F, Callaway RM, Meron E. Evidence for scale-dependent root-antation feedback and its role in halting the spread of a pantropical shrub into an endemic sedge. PNAS NEXUS 2023; 2:pgac294. [PMID: 36733292 PMCID: PMC9887939 DOI: 10.1093/pnasnexus/pgac294] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/12/2022] [Indexed: 04/12/2023]
Abstract
Vegetation pattern formation is a widespread phenomenon in resource-limited environments, but the driving mechanisms are largely unconfirmed empirically. Combining results of field studies and mathematical modeling, empirical evidence for a generic pattern-formation mechanism is demonstrated with the clonal shrub Guilandina bonduc L. (hereafter Guilandina) on the Brazilian island of Trindade. The mechanism is associated with water conduction by laterally spread roots and root augmentation as the shoot grows-a crucial element in the positive feedback loop that drives spatial patterning. Assuming precipitation-dependent root-shoot relations, the model accounts for the major vegetation landscapes on Trindade Island, substantiating lateral root augmentation as the driving mechanism of Guilandina patterning. Guilandina expands into surrounding communities dominated by the Trindade endemic, Cyperus atlanticus Hemsl. (hereafter Cyperus). It appears to do so by decreasing the water potential in soils below Cyperus through its dense lateral roots, leaving behind a patchy Guilandina-only landscape. We use this system to highlight a novel form of invasion, likely to apply to many other systems where the invasive species is pattern-forming. Depending on the level of water stress, the invasion can take two distinct forms: (i) a complete invasion at low stress that culminates in a patchy Guilandina-only landscape through a spot-replication process, and (ii) an incomplete invasion at high stress that begins but does not spread, forming isolated Guilandina spots of fixed size, surrounded by bare-soil halos, in an otherwise uniform Cyperus grassland. Thus, drier climates may act selectively on pattern-forming invasive species, imposing incomplete invasion and reducing the negative effects on native species.
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Affiliation(s)
- Jamie J R Bennett
- Department of Solar Energy and Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 8499000, Israel
| | - Anabele S Gomes
- Department of Botany, University of Brasília, Brasília 70910-900, Brazil
| | - Michel A Ferré
- Department of Solar Energy and Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 8499000, Israel
| | - Bidesh K Bera
- Department of Solar Energy and Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 8499000, Israel
| | - Fabian Borghetti
- Department of Botany, University of Brasília, Brasília 70910-900, Brazil
| | - Ragan M Callaway
- Department of Wildlife Biology, University of Montana, Missoula, MT 59812, USA
| | - Ehud Meron
- To whom correspondence should be addressed.
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Grünzweig JM, De Boeck HJ, Rey A, Santos MJ, Adam O, Bahn M, Belnap J, Deckmyn G, Dekker SC, Flores O, Gliksman D, Helman D, Hultine KR, Liu L, Meron E, Michael Y, Sheffer E, Throop HL, Tzuk O, Yakir D. Dryland mechanisms could widely control ecosystem functioning in a drier and warmer world. Nat Ecol Evol 2022; 6:1064-1076. [PMID: 35879539 DOI: 10.1038/s41559-022-01779-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/28/2022] [Indexed: 11/09/2022]
Abstract
Responses of terrestrial ecosystems to climate change have been explored in many regions worldwide. While continued drying and warming may alter process rates and deteriorate the state and performance of ecosystems, it could also lead to more fundamental changes in the mechanisms governing ecosystem functioning. Here we argue that climate change will induce unprecedented shifts in these mechanisms in historically wetter climatic zones, towards mechanisms currently prevalent in dry regions, which we refer to as 'dryland mechanisms'. We discuss 12 dryland mechanisms affecting multiple processes of ecosystem functioning, including vegetation development, water flow, energy budget, carbon and nutrient cycling, plant production and organic matter decomposition. We then examine mostly rare examples of the operation of these mechanisms in non-dryland regions where they have been considered irrelevant at present. Current and future climate trends could force microclimatic conditions across thresholds and lead to the emergence of dryland mechanisms and their increasing control over ecosystem functioning in many biomes on Earth.
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Affiliation(s)
- José M Grünzweig
- Institute of Plant Sciences and Genetics in Agriculture, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel.
| | - Hans J De Boeck
- Plants and Ecosystems, Department of Biology, Universiteit Antwerpen, Wilrijk, Belgium
| | - Ana Rey
- Department of Biogeography and Global Change, National Museum of Natural History, Spanish National Research Council (CSIC), Madrid, Spain
| | - Maria J Santos
- Department of Geography, University of Zurich, Zurich, Switzerland
| | - Ori Adam
- The Fredy and Nadine Herrmann Institute of Earth Sciences, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jayne Belnap
- US Geological Survey, Southwest Biological Science Center, Moab, UT, USA
| | - Gaby Deckmyn
- Plants and Ecosystems, Department of Biology, Universiteit Antwerpen, Wilrijk, Belgium
| | - Stefan C Dekker
- Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, the Netherlands
| | - Omar Flores
- Plants and Ecosystems, Department of Biology, Universiteit Antwerpen, Wilrijk, Belgium.,Department of Biogeography and Global Change, National Museum of Natural History, Spanish National Research Council (CSIC), Madrid, Spain
| | - Daniel Gliksman
- Institute for Hydrology and Meteorology, Faculty of Environmental Sciences, Technische Universität Dresden, Tharandt, Germany.,Institute of Geography, Technische Universität Dresden, Dresden, Germany
| | - David Helman
- Institute of Environmental Sciences, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel.,Advanced School for Environmental Studies, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, USA
| | - Lingli Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing, China
| | - Ehud Meron
- Department of Physics, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Department of Solar Energy and Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Israel
| | - Yaron Michael
- Institute of Environmental Sciences, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel
| | - Efrat Sheffer
- Institute of Plant Sciences and Genetics in Agriculture, the Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel
| | - Heather L Throop
- School of Earth and Space Exploration, and School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Omer Tzuk
- Department of Physics, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Department of Industrial Engineering, Faculty of Engineering, Tel-Aviv University, Tel Aviv-Yafo, Israel
| | - Dan Yakir
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
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