1
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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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van de Vijsel RC, Hernández-García E, Orfila A, Gomila D. Optimal wave reflection as a mechanism for seagrass self-organization. Sci Rep 2023; 13:20278. [PMID: 37985847 PMCID: PMC10662035 DOI: 10.1038/s41598-023-46788-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/05/2023] [Indexed: 11/22/2023] Open
Abstract
Ecosystems threatened by climate change can boost their resilience by developing spatial patterns. Spatially regular patterns in wave-exposed seagrass meadows are attributed to self-organization, yet underlying mechanisms are not well understood. Here, we show that these patterns could emerge from feedbacks between wave reflection and seagrass-induced bedform growth. We derive a theoretical model for surface waves propagating over a growing seagrass bed. Wave-induced bed shear stress shapes bedforms which, in turn, trigger wave reflection. Numerical simulations show seagrass pattern development once wave forcing exceeds a critical amplitude. In line with Mediterranean Sea field observations, these patterns have half the wavelength of the forcing waves. Our results raise the hypothesis that pattern formation optimizes the potential of seagrass meadows to reflect wave energy, and a clear direction for future field campaigns. If wave-reflecting pattern formation increases ecosystem resilience under globally intensifying wave climates, these ecosystems may inspire nature-based coastal protection measures.
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Affiliation(s)
- Roeland C van de Vijsel
- IFISC (CSIC-UIB). Institute for Cross-Disciplinary Physics and Complex Systems, 07122, Palma, Mallorca, Spain.
- Now at: Hydrology and Environmental Hydraulics Group, Wageningen University, Wageningen, The Netherlands.
| | - Emilio Hernández-García
- IFISC (CSIC-UIB). Institute for Cross-Disciplinary Physics and Complex Systems, 07122, Palma, Mallorca, Spain
| | - Alejandro Orfila
- IMEDEA (CSIC-UIB). Mediterranean Institute for Advanced Studies, 07190, Esporles, Mallorca, Spain
| | - Damià Gomila
- IFISC (CSIC-UIB). Institute for Cross-Disciplinary Physics and Complex Systems, 07122, Palma, Mallorca, Spain
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3
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Al Saadi F, Parra-Rivas P. Transitions between dissipative localized structures in the simplified Gilad-Meron model for dryland plant ecology. CHAOS (WOODBURY, N.Y.) 2023; 33:033129. [PMID: 37003806 DOI: 10.1063/5.0133576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
Spatially extended patterns and multistability of possible different states are common in many ecosystems, and their combination has an important impact on their dynamical behaviors. One potential combination involves tristability between a patterned state and two different uniform states. Using a simplified version of the Gilad-Meron model for dryland ecosystems, we study the organization, in bifurcation terms, of the localized structures arising in tristable regimes. These states are generally related to the concept of wave front locking and appear in the form of spots and gaps of vegetation. We find that the coexistence of localized spots and gaps, within tristable configurations, yields the appearance of hybrid states. We also study the emergence of spatiotemporal localized states consisting of a portion of a periodic pattern embedded in a uniform Hopf-like oscillatory background in a subcritical Turing-Hopf dynamical regime.
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Affiliation(s)
- Fahad Al Saadi
- Department of Systems Engineering, Military Technological College, Muscat, Oman
| | - Pedro Parra-Rivas
- Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni, Sapienza Universitá di Roma, via Eudossiana 18, 00184 Rome, Italy
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4
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Self-organized sulfide-driven traveling pulses shape seagrass meadows. Proc Natl Acad Sci U S A 2023; 120:e2216024120. [PMID: 36623188 PMCID: PMC9934305 DOI: 10.1073/pnas.2216024120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Seagrasses provide multiple ecosystem services and act as intense carbon sinks in coastal regions around the globe but are threatened by multiple anthropogenic pressures, leading to enhanced seagrass mortality that reflects in the spatial self-organization of the meadows. Spontaneous spatial vegetation patterns appear in such different ecosystems as drylands, peatlands, salt marshes, or seagrass meadows, and the mechanisms behind this phenomenon are still an open question in many cases. Here, we report on the formation of vegetation traveling pulses creating complex spatiotemporal patterns and rings in Mediterranean seagrass meadows. We show that these structures emerge due to an excitable behavior resulting from the coupled dynamics of vegetation and porewater hydrogen sulfide, toxic to seagrass, in the sediment. The resulting spatiotemporal patterns resemble those formed in other physical, chemical, and biological excitable media, but on a much larger scale. Based on theory, we derive a model that reproduces the observed seascapes and predicts the annihilation of these circular structures as they collide, a distinctive feature of excitable pulses. We show also that the patterns in field images and the empirically resolved radial profiles of vegetation density and sediment sulfide concentration across the structures are consistent with predictions from the theoretical model, which shows these structures to have diagnostic value, acting as a harbinger of the terminal state of the seagrass meadows prior to their collapse.
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5
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Phase-separation physics underlies new theory for the resilience of patchy ecosystems. Proc Natl Acad Sci U S A 2023; 120:e2202683120. [PMID: 36595670 PMCID: PMC9926271 DOI: 10.1073/pnas.2202683120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Spatial self-organization of ecosystems into large-scale (from micron to meters) patterns is an important phenomenon in ecology, enabling organisms to cope with harsh environmental conditions and buffering ecosystem degradation. Scale-dependent feedbacks provide the predominant conceptual framework for self-organized spatial patterns, explaining regular patterns observed in, e.g., arid ecosystems or mussel beds. Here, we highlight an alternative mechanism for self-organized patterns, based on the aggregation of a biotic or abiotic species, such as herbivores, sediment, or nutrients. Using a generalized mathematical model, we demonstrate that ecosystems with aggregation-driven patterns have fundamentally different dynamics and resilience properties than ecosystems with patterns that formed through scale-dependent feedbacks. Building on the physics theory for phase-separation dynamics, we show that patchy ecosystems with aggregation patterns are more vulnerable than systems with patterns formed through scale-dependent feedbacks, especially at small spatial scales. This is because local disturbances can trigger large-scale redistribution of resources, amplifying local degradation. Finally, we show that insights from physics, by providing mechanistic understanding of the initiation of aggregation patterns and their tendency to coarsen, provide a new indicator framework to signal proximity to ecological tipping points and subsequent ecosystem degradation for this class of patchy ecosystems.
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6
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Mayol E, Boada J, Pérez M, Sanmartí N, Minguito-Frutos M, Arthur R, Alcoverro T, Alonso D, Romero J. Understanding the depth limit of the seagrass Cymodocea nodosa as a critical transition: Field and modeling evidence. MARINE ENVIRONMENTAL RESEARCH 2022; 182:105765. [PMID: 36252284 DOI: 10.1016/j.marenvres.2022.105765] [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: 07/21/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Changes in light and sediment conditions can sometimes trigger abrupt regime shifts in seagrass meadows resulting in dramatic and unexpected die-offs of seagrass. Light attenuates rapidly with depth, and in seagrass systems with non-linear behaviours, can serve as a sharp boundary beyond which the meadow transitions to bare sand. Determining system behaviour is therefore essential to ensuring resilience is maintained and to prevent stubborn critical ecosystem transitions caused by declines in water quality. Here we combined field and modelling studies to explore the transition from meadow to bare sand in the seagrass Cymodocea nodosa at the limit of its depth distribution in a shallow, light-limited bay. We first describe the relationship between light availability and seagrass density along a depth gradient in an extensive unfragmented meadow (Alfacs bay, NE Spain). We then develop a simple mechanistic model to characterise system behaviour. In the field, we identified sharp decline in shoot density beyond a threshold of ∼1.9 m depth, shifting from a vegetated state to bare sand. The dynamic population model we developed assumes light-dependent growth and an inverse density-dependent mortality due to facilitation between shoots (mortality rate decreases as shoot density increases). The model closely tracked our empirical observations, and both the model and the field data showed signs of bistability. This strongly suggests that the depth limit of C. nodosa is a critical transition driven by photosynthetic light requirements. While the mechanisms still need to be confirmed with experimental evidence, recognizing the non-linear behaviour of C. nodosa meadows is vital not only in improving our understanding of light effects on seagrass dynamics, but also in managing shallow-water meadows. Given the shallow threshold (<2m), light-limited systems may experience significant and recalcitrant meadow retractions with even small changes in sediment and light conditions. Understanding the processes underlying meadow resilience can inform the maintenance and restoration of meadows worldwide.
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Affiliation(s)
- Elvira Mayol
- Institut Mediterrani d'Estudis Avançats (IMEDEA-CSIC), Carrer Miquel Marqués 21, 07190, Esporles, Spain.
| | - Jordi Boada
- Laboratoire d'Océanographie de Villefranche, Sorbonne Université, Villefranche-sur-Mer, France
| | - Marta Pérez
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain
| | - Neus Sanmartí
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain
| | - Mario Minguito-Frutos
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Carrer d'Accés a la cala Sant Francesc 14, 17300, Blanes, Spain
| | - Rohan Arthur
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Carrer d'Accés a la cala Sant Francesc 14, 17300, Blanes, Spain; Nature Conservation Foundation, 1311 Amritha, 12th Cross, Vijayanagara 1st Stage, Mysore, 570017, India
| | - Teresa Alcoverro
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Carrer d'Accés a la cala Sant Francesc 14, 17300, Blanes, Spain; Nature Conservation Foundation, 1311 Amritha, 12th Cross, Vijayanagara 1st Stage, Mysore, 570017, India
| | - David Alonso
- Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Carrer d'Accés a la cala Sant Francesc 14, 17300, Blanes, Spain
| | - Javier Romero
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain
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7
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Sun GQ, Li L, Li J, Liu C, Wu YP, Gao S, Wang Z, Feng GL. Impacts of climate change on vegetation pattern: Mathematical modeling and data analysis. Phys Life Rev 2022; 43:239-270. [PMID: 36343569 DOI: 10.1016/j.plrev.2022.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/27/2022]
Abstract
Climate change has become increasingly severe, threatening ecosystem stability and, in particular, biodiversity. As a typical indicator of ecosystem evolution, vegetation growth is inevitably affected by climate change, and therefore has a great potential to provide valuable information for addressing such ecosystem problems. However, the impacts of climate change on vegetation growth, especially the spatial and temporal distribution of vegetation, are still lacking of comprehensive exposition. To this end, this review systematically reveals the influences of climate change on vegetation dynamics in both time and space by dynamical modeling the interactions of meteorological elements and vegetation growth. Moreover, we characterize the long-term evolution trend of vegetation growth under climate change in some typical regions based on data analysis. This work is expected to lay a necessary foundation for systematically revealing the coupling effect of climate change on the ecosystem.
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Affiliation(s)
- Gui-Quan Sun
- Department of Mathematics, North University of China, Taiyuan, 030051, China; Complex Systems Research Center, Shanxi University, Taiyuan, 030006, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519082, China.
| | - Li Li
- School of Computer and Information Technology, Shanxi University, Taiyuan, 030006, China
| | - Jing Li
- School of Applied Mathematics, Shanxi University of Finance and Economics, Taiyuan, 030006, China
| | - Chen Liu
- Center for Ecology and Environmental Sciences, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Yong-Ping Wu
- College of Physics Science and Technology, Yangzhou University, Yangzhou, 225002, China
| | - Shupeng Gao
- School of Mechanical Engineering and School of Artificial Intelligence, Optics and Electronics (iOPEN), Northwestern Polytechnical University, Xian, 710072, China
| | - Zhen Wang
- School of Mechanical Engineering and School of Artificial Intelligence, Optics and Electronics (iOPEN), Northwestern Polytechnical University, Xian, 710072, China.
| | - Guo-Lin Feng
- College of Physics Science and Technology, Yangzhou University, Yangzhou, 225002, China; Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing, 100081, China.
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8
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Zhang J, Zhang S, Wang C, Wang W, Ma L. Flow characteristics of open channels based on patch distribution of partially discontinuous rigid combined vegetation. FRONTIERS IN PLANT SCIENCE 2022; 13:976646. [PMID: 36304404 PMCID: PMC9595071 DOI: 10.3389/fpls.2022.976646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
To clarify the flow characteristics of open channels under the combined distribution of vegetation in a patch, this study used the computational fluid dynamics tool FLUENT and the Reynolds stress model to design four combined and four discrete distribution modes under two different inundation states (submerged and non-submerged). The flow characteristics of longitudinally discontinuous rigid vegetation patches occupying half the width of the channel were numerically simulated. The numerical model is verified by indoor open channel flume experiments, and the obtained model data is in good agreement with the measured data. The results showed that: 1) The diameter of vegetation is an important factor affecting the wake structure. Under the submerged condition. 2)The submerged state, distribution pattern and combination form of vegetation are important factors that affect the distribution of flow velocity and change the structure of water flow. That is, the influence of vegetation distribution pattern on flow velocity and turbulence intensity under submerged condition is significantly weaker than that under non-submerged condition, and the flow velocity in non-vegetation area is significantly higher than that in vegetation area. The increase in the combined vegetation comprehensive stem thickness and the discrete degree resulted in an increase in the difference in flow velocity and turbulence intensity. 3) As the water flowed downstream, the flow velocity along the vegetated area continuously decreased, while it increased continuously along the non-vegetated area, and the difference in flow velocity between the two areas became more apparent. 4) The inundation state and combination characteristics of vegetation were important factors affecting the Reynolds stress of the channel location in the patch area.
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9
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Moreno-Spiegelberg P, Arinyo-I-Prats A, Ruiz-Reynés D, Matias MA, Gomila D. Bifurcation structure of traveling pulses in type-I excitable media. Phys Rev E 2022; 106:034206. [PMID: 36266808 DOI: 10.1103/physreve.106.034206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 08/01/2022] [Indexed: 06/16/2023]
Abstract
We study the scenario in which traveling pulses emerge in a prototypical type-I one-dimensional excitable medium, which exhibits two different routes to excitable behavior, mediated by a homoclinic (saddle-loop) and a saddle-node on the invariant cycle bifurcations. We characterize the region in parameter space in which traveling pulses are stable together with the different bifurcations behind either their destruction or loss of stability. In particular, some of the bifurcations delimiting the stability region have been connected, using singular limits, with the two different scenarios that mediated type-I local excitability. Finally, the existence of traveling pulses has been linked to a drift pitchfork instability of localized steady structures.
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Affiliation(s)
- Pablo Moreno-Spiegelberg
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
| | - Andreu Arinyo-I-Prats
- Institute of Computer Science, Czech Academy of Sciences, 182 07 Prague 8, Czech Republic
| | - Daniel Ruiz-Reynés
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), B-3000 Leuven, Belgium
| | - Manuel A Matias
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
| | - Damià Gomila
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
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10
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Llabrés E, Mayol E, Marbà N, Sintes T. A mathematical model for inter‐specific interactions in seagrasses. OIKOS 2022. [DOI: 10.1111/oik.09296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eva Llabrés
- Inst. for Cross‐Disciplinary Physics and Complex Systems, IFISC (CSIC‐UIB), Univ. de les Illes Balears Palma de Mallorca Spain
| | - Elvira Mayol
- Dept of Global Change Research, Mediterranean Inst. for Advanced Studies, IMEDEA (CSIC‐UIB) Esporles (Mallorca) Spain
| | - Núria Marbà
- Dept of Global Change Research, Mediterranean Inst. for Advanced Studies, IMEDEA (CSIC‐UIB) Esporles (Mallorca) Spain
| | - Tomàs Sintes
- Inst. for Cross‐Disciplinary Physics and Complex Systems, IFISC (CSIC‐UIB), Univ. de les Illes Balears Palma de Mallorca Spain
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11
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Spatial patterns in ecological systems: from microbial colonies to landscapes. Emerg Top Life Sci 2022; 6:245-258. [PMID: 35678374 DOI: 10.1042/etls20210282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 11/17/2022]
Abstract
Self-organized spatial patterns are ubiquitous in ecological systems and allow populations to adopt non-trivial spatial distributions starting from disordered configurations. These patterns form due to diverse nonlinear interactions among organisms and between organisms and their environment, and lead to the emergence of new (eco)system-level properties unique to self-organized systems. Such pattern consequences include higher resilience and resistance to environmental changes, abrupt ecosystem collapse, hysteresis loops, and reversal of competitive exclusion. Here, we review ecological systems exhibiting self-organized patterns. We establish two broad pattern categories depending on whether the self-organizing process is primarily driven by nonlinear density-dependent demographic rates or by nonlinear density-dependent movement. Using this organization, we examine a wide range of observational scales, from microbial colonies to whole ecosystems, and discuss the mechanisms hypothesized to underlie observed patterns and their system-level consequences. For each example, we review both the empirical evidence and the existing theoretical frameworks developed to identify the causes and consequences of patterning. Finally, we trace qualitative similarities across systems and propose possible ways of developing a more quantitative understanding of how self-organization operates across systems and observational scales in ecology.
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12
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Open-Source Analysis of Submerged Aquatic Vegetation Cover in Complex Waters Using High-Resolution Satellite Remote Sensing: An Adaptable Framework. REMOTE SENSING 2022. [DOI: 10.3390/rs14020267] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Despite being recognized as a key component of shallow-water ecosystems, submerged aquatic vegetation (SAV) remains difficult to monitor over large spatial scales. Because of SAV’s structuring capabilities, high-resolution monitoring of submerged landscapes could generate highly valuable ecological data. Until now, high-resolution remote sensing of SAV has been largely limited to applications within costly image analysis software. In this paper, we propose an example of an adaptable open-sourced object-based image analysis (OBIA) workflow to generate SAV cover maps in complex aquatic environments. Using the R software, QGIS and Orfeo Toolbox, we apply radiometric calibration, atmospheric correction, a de-striping correction, and a hierarchical iterative OBIA random forest classification to generate SAV cover maps based on raw DigitalGlobe multispectral imagery. The workflow is applied to images taken over two spatially complex fluvial lakes in Quebec, Canada, using Quickbird-02 and Worldview-03 satellites. Classification performance based on training sets reveals conservative SAV cover estimates with less than 10% error across all classes except for lower SAV growth forms in the most turbid waters. In light of these results, we conclude that it is possible to monitor SAV distribution using high-resolution remote sensing within an open-sourced environment with a flexible and functional workflow.
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13
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Arinyo-I-Prats A, Moreno-Spiegelberg P, Matias MA, Gomila D. Traveling pulses in type-I excitable media. Phys Rev E 2021; 104:L052203. [PMID: 34942747 DOI: 10.1103/physreve.104.l052203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 10/28/2021] [Indexed: 01/17/2023]
Abstract
We consider a general model exhibiting type-I excitability mediated by a homoclinic and a saddle node on the invariant circle bifurcations. We show how the distinct properties of type-I with respect to type-II excitability confer unique features to traveling pulses in excitable media. They inherit the characteristic divergence of type-I excitable trajectories at threshold exhibiting analogous scalings in the spatial thickness of the pulses. Our results pave the way to identify basic underlying mechanisms behind type-I excitable pulses based solely on the characteristics of the pulse.
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Affiliation(s)
- Andreu Arinyo-I-Prats
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain.,Institute of Computer Science, Czech Academy of Sciences, 182 07 Praha 8, Czech Republic
| | - Pablo Moreno-Spiegelberg
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
| | - Manuel A Matias
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
| | - Damià Gomila
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
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14
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Rietkerk M, Bastiaansen R, Banerjee S, van de Koppel J, Baudena M, Doelman A. Evasion of tipping in complex systems through spatial pattern formation. Science 2021; 374:eabj0359. [PMID: 34618584 DOI: 10.1126/science.abj0359] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Max Rietkerk
- Copernicus Institute of Sustainable Development, Utrecht University, 3508 TC, Utrecht, Netherlands
| | - Robbin Bastiaansen
- Department of Physics, Institute for Marine and Atmospheric Research Utrecht, Utrecht University, 3508 TA, Utrecht, Netherlands
| | - Swarnendu Banerjee
- Copernicus Institute of Sustainable Development, Utrecht University, 3508 TC, Utrecht, Netherlands.,The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113, India.,Indian Statistical Institute, Agricultural and Ecological Research Unit, Kolkata 700108, India
| | - Johan van de Koppel
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, 4400 AC, Yerseke, Netherlands.,Groningen Institute for Evolutionary Life Sciences, Conservation Ecology Group, University of Groningen, 9700 CC, Groningen, Netherlands
| | - Mara Baudena
- Copernicus Institute of Sustainable Development, Utrecht University, 3508 TC, Utrecht, Netherlands.,National Research Council of Italy, Institute of Atmospheric Sciences and Climate (CNR-ISAC), 10133 Torino, Italy
| | - Arjen Doelman
- Mathematical Institute, Leiden University, 2300 RA, Leiden, Netherlands
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15
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High-integrity human intervention in ecosystems: Tracking self-organization modes. PLoS Comput Biol 2021; 17:e1009427. [PMID: 34587157 PMCID: PMC8504872 DOI: 10.1371/journal.pcbi.1009427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 10/11/2021] [Accepted: 09/06/2021] [Indexed: 11/19/2022] Open
Abstract
Humans play major roles in shaping and transforming the ecology of Earth. Unlike natural drivers of ecosystem change, which are erratic and unpredictable, human intervention in ecosystems generally involves planning and management, but often results in detrimental outcomes. Using model studies and aerial-image analysis, we argue that the design of a successful human intervention form calls for the identification of the self-organization modes that drive ecosystem change, and for studying their dynamics. We demonstrate this approach with two examples: grazing management in drought-prone ecosystems, and rehabilitation of degraded vegetation by water harvesting. We show that grazing can increase the resilience to droughts, rather than imposing an additional stress, if managed in a spatially non-uniform manner, and that fragmental restoration along contour bunds is more resilient than the common practice of continuous restoration in vegetation stripes. We conclude by discussing the need for additional studies of self-organization modes and their dynamics. Human intervention in ecosystems is motivated by various functional needs, such as provisioning ecosystem services, but often has unexpected detrimental outcomes. A major question in ecology is how to manage human intervention so as to achieve its goal without impairing ecosystem function. The main idea pursued here is the need to identify the inherent response ways of ecosystems to disturbances, and use them as road maps for conducting interventions. This approach is demonstrated mathematically using two contexts, grazing management and vegetation restoration, and compared to remote sensing data for the latter. Among the surprising insights obtained is the beneficial effect of grazing, in terms of resilience to droughts, that can be achieved by managing it non-uniformly in space.
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16
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Bera BK, Tzuk O, Bennett JJR, Meron E. Linking spatial self-organization to community assembly and biodiversity. eLife 2021; 10:e73819. [PMID: 34570698 PMCID: PMC8497052 DOI: 10.7554/elife.73819] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/19/2021] [Indexed: 11/29/2022] Open
Abstract
Temporal shifts to drier climates impose environmental stresses on plant communities that may result in community reassembly and threatened ecosystem services, but also may trigger self-organization in spatial patterns of biota and resources, which act to relax these stresses. The complex relationships between these counteracting processes - community reassembly and spatial self-organization - have hardly been studied. Using a spatio-temporal model of dryland plant communities and a trait-based approach, we study the response of such communities to increasing water-deficit stress. We first show that spatial patterning acts to reverse shifts from fast-growing species to stress-tolerant species, as well as to reverse functional-diversity loss. We then show that spatial self-organization buffers the impact of further stress on community structure. Finally, we identify multistability ranges of uniform and patterned community states and use them to propose forms of non-uniform ecosystem management that integrate the need for provisioning ecosystem services with the need to preserve community structure.
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Affiliation(s)
- Bidesh K Bera
- Department of Solar Energy and Environmental Physics, BIDR, Ben-Gurion University of the NegevSede Boqer CampusIsrael
| | - Omer Tzuk
- Physics Department, Ben-Gurion University of the NegevBeer ShevaIsrael
| | - Jamie JR Bennett
- Department of Solar Energy and Environmental Physics, BIDR, Ben-Gurion University of the NegevSede Boqer CampusIsrael
| | - Ehud Meron
- Department of Solar Energy and Environmental Physics, BIDR, Ben-Gurion University of the NegevSede Boqer CampusIsrael
- Physics Department, Ben-Gurion University of the NegevBeer ShevaIsrael
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17
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Belowground feedbacks as drivers of spatial self-organization and community assembly. Phys Life Rev 2021; 38:1-24. [PMID: 34334324 DOI: 10.1016/j.plrev.2021.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 02/03/2023]
Abstract
Vegetation patterning in water-limited and other resource-limited ecosystems highlights spatial self-organization processes as potentially key drivers of community assembly. These processes provide insight into predictable landscape-level relationships between organisms and their abiotic environment in the form of regular and irregular patterns of biota and resources. However, two aspects have largely been overlooked; the roles played by plant - soil-biota feedbacks and allelopathy in spatial self-organization, and their potential contribution, along with plant-resource feedbacks, to community assembly through spatial self-organization. Here, we expand the drivers of spatial self-organization from a focus on plant-resource feedbacks to include plant - soil-biota feedbacks and allelopathy, and integrate concepts of nonlinear physics and community ecology to generate a new hypothesis. According to this hypothesis, below-ground processes can affect community assemblages through two types of spatial self-organization, global and local. The former occurs simultaneously across whole ecosystems, leading to self-organized patterns of biota, allelochemicals and resources, and niche partitioning. The latter occurs locally in ecotones, and determines ecotone structure and motion, invasion dynamics, and species coexistence. Studies of the two forms of spatial self-organization are important for understanding the organization of plant communities in drier climates which are likely to involve spatial patterning or re-patterning. Such studies are also important for developing new practices of ecosystem management, based on local manipulations at ecotones, to slow invasion dynamics or induce transitions from transitive to intransitive networks of interspecific interactions which increase species diversity.
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18
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He J, Rindi L, Mintrone C, Benedetti‐Cecchi L. Exogenous disturbances and endogenous self‐organized processes are not mutually exclusive drivers of spatial patterns in macroalgal assemblages. OIKOS 2021. [DOI: 10.1111/oik.07908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jianyu He
- Dept of Biology, Univ. of Pisa, CoNISMa Pisa Italy
- Marine Science and Technical College, Zhejiang Ocean Univ., Zhoushan City Zhejiang China
| | - Luca Rindi
- Dept of Biology, Univ. of Pisa, CoNISMa Pisa Italy
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19
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Garlaschi S, Gupta D, Maritan A, Azaele S. Ginzburg-Landau amplitude equation for nonlinear nonlocal models. Phys Rev E 2021; 103:022210. [PMID: 33736032 DOI: 10.1103/physreve.103.022210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/21/2021] [Indexed: 11/07/2022]
Abstract
Regular spatial structures emerge in a wide range of different dynamics characterized by local and/or nonlocal coupling terms. In several research fields this has spurred the study of many models, which can explain pattern formation. The modulations of patterns, occurring on long spatial and temporal scales, cannot be captured by linear approximation analysis. Here, we show that, starting from a general model with long range couplings displaying patterns, the spatiotemporal evolution of large-scale modulations at the onset of instability is ruled by the well-known Ginzburg-Landau equation, independently of the details of the dynamics. Hence, we demonstrate the validity of such equation in the description of the behavior of a wide class of systems. We introduce a mathematical framework that is also able to retrieve the analytical expressions of the coefficients appearing in the Ginzburg-Landau equation as functions of the model parameters. Such framework can include higher order nonlocal interactions and has much larger applicability than the model considered here, possibly including pattern formation in models with very different physical features.
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Affiliation(s)
- Stefano Garlaschi
- Dipartimento di Fisica e Astronomia "Galileo Galilei", Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy
| | - Deepak Gupta
- Dipartimento di Fisica e Astronomia "Galileo Galilei", Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy
| | - Amos Maritan
- Dipartimento di Fisica e Astronomia "Galileo Galilei", Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy
| | - Sandro Azaele
- Dipartimento di Fisica e Astronomia "Galileo Galilei", Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy
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20
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Zhao LX, Zhang K, Siteur K, Li XZ, Liu QX, van de Koppel J. Fairy circles reveal the resilience of self-organized salt marshes. SCIENCE ADVANCES 2021; 7:7/6/eabe1100. [PMID: 33547078 PMCID: PMC7864568 DOI: 10.1126/sciadv.abe1100] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/17/2020] [Indexed: 05/21/2023]
Abstract
Spatial patterning is a fascinating theme in both theoretical and experimental ecology. It reveals resilience and stability to withstand external disturbances and environmental stresses. However, existing studies mainly focus on well-developed persistent patterns rather than transient patterns in self-organizing ecosystems. Here, combining models and experimental evidence, we show that transient fairy circle patterns in intertidal salt marshes can both infer the underlying ecological mechanisms and provide a measure of resilience. The models based on sulfide accumulation and nutrient depletion mechanisms reproduced the field-observed fairy circles, providing a generalized perspective on the emergence of transient patterns in salt marsh ecosystems. Field experiments showed that nitrogen fertilization mitigates depletion stress and shifts plant growth from negative to positive in the center of patches. Hence, nutrient depletion plays an overriding role, as only this process can explain the concentric rings. Our findings imply that the emergence of transient patterns can identify the ecological processes underlying pattern formation and the factors determining the ecological resilience of salt marsh ecosystems.
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Affiliation(s)
- Li-Xia Zhao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration and Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education and Shanghai Science and Technology Committee, Shanghai, China
| | - Kang Zhang
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration and Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Koen Siteur
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration and Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Department of Estuarine and Delta Systems, Royal Netherlands Institute of Sea Research, Yerseke 4401 NT, Netherlands
| | - Xiu-Zhen Li
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
- Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education and Shanghai Science and Technology Committee, Shanghai, China
| | - Quan-Xing Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China.
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration and Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education and Shanghai Science and Technology Committee, Shanghai, China
| | - Johan van de Koppel
- Department of Estuarine and Delta Systems, Royal Netherlands Institute of Sea Research, Yerseke 4401 NT, Netherlands.
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9700 CC, Netherlands
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21
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Shapira AZ, Uecker H, Yochelis A. Stripes on finite domains: Why the zigzag instability is only a partial story. CHAOS (WOODBURY, N.Y.) 2020; 30:073104. [PMID: 32752648 DOI: 10.1063/5.0006126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Stationary periodic patterns are widespread in natural sciences, ranging from nano-scale electrochemical and amphiphilic systems to mesoscale fluid, chemical, and biological media and to macro-scale vegetation and cloud patterns. Their formation is usually due to a primary symmetry breaking of a uniform state to stripes, often followed by secondary instabilities to form zigzag and labyrinthine patterns. These secondary instabilities are well studied under idealized conditions of an infinite domain; however, on finite domains, the situation is more subtle since the unstable modes depend also on boundary conditions. Using two prototypical models, the Swift-Hohenberg equation and the forced complex Ginzburg-Landau equation, we consider finite size domains with no flux boundary conditions transversal to the stripes and reveal a distinct mixed-mode instability that lies in between the classical zigzag and the Eckhaus lines. This explains the stability of stripes in the mildly zigzag unstable regime and, after crossing the mixed-mode line, the evolution of zigzag stripes in the bulk of the domain and the formation of defects near the boundaries. The results are of particular importance for problems with large timescale separation, such as bulk-heterojunction deformations in organic photovoltaic and vegetation in semi-arid regions, where early temporal transients may play an important role.
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Affiliation(s)
- Alon Z Shapira
- Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion 8499000, Israel
| | - Hannes Uecker
- Institute for Mathematics, Carl von Ossietzky University of Oldenburg, PF 2503, 26111 Oldenburg, Germany
| | - Arik Yochelis
- Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion 8499000, Israel
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22
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Parra-Rivas P, Fernandez-Oto C. Formation of localized states in dryland vegetation: Bifurcation structure and stability. Phys Rev E 2020; 101:052214. [PMID: 32575306 DOI: 10.1103/physreve.101.052214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 04/27/2020] [Indexed: 11/07/2022]
Abstract
We study theoretically the emergence of localized states of vegetation close to the onset of desertification. These states are formed through the locking of vegetation fronts, connecting a uniform vegetation state with a bare soil state, which occurs nearby the Maxwell point of the system. To study these structures we consider a universal model of vegetation dynamics in drylands, which has been obtained as the normal form for different vegetation models. Close to the Maxwell point localized gaps and spots of vegetation exist and undergo collapsed snaking. The presence of gaps strongly suggest that the ecosystem may undergo a recovering process. In contrast, the presence of spots may indicate that the ecosystem is close to desertification.
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Affiliation(s)
- P Parra-Rivas
- Service OPERA-photonics, Universit libre de Bruxelles, 50 Avenue F. D. Roosevelt, CP 194/5, B-1050 Bruxelles, Belgium.,Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - C Fernandez-Oto
- Complex Systems Group, Facultad de Ingenieria y Ciencias Aplicadas, Universidad de los Andes, Av. Mon. Alvaro del Portillo 12455 Santiago, Chile
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23
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Ruiz-Reynés D, Gomila D. Distribution of growth directions in meadows of clonal plants. Phys Rev E 2019; 100:052208. [PMID: 31870011 DOI: 10.1103/physreve.100.052208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Indexed: 11/07/2022]
Abstract
Clonal growth plants are abundant in both terrestrial and marine ecosystems. Some marine species are particularly important since they provide essential ecosystem services in the shores of all continents except Antarctica. For the appropriate modelization of clonal growth the discretization of the growth direction angle has to be carefully treated to correctly describe the dynamics of the meadow. Specifically, determining the minimum number of growth directions is important to maximize the efficiency of numerical simulations. We show that the presence of neutral modes in the growth direction angle tends to make the distribution of the growth directions uniform in the presence of noise, allowing us to choose the minimal number of discrete angles compatible with the branching. We also show that the formation of spatial patterns induces small differences in the population density within these different growth directions.
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Affiliation(s)
- D Ruiz-Reynés
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - D Gomila
- IFISC (CSIC-UIB), Instituto de Física Interdisciplinar y Sistemas Complejos, Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
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24
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Parra-Rivas P, Gelens L, Leo F. Localized structures in dispersive and doubly resonant optical parametric oscillators. Phys Rev E 2019; 100:032219. [PMID: 31639956 DOI: 10.1103/physreve.100.032219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Indexed: 06/10/2023]
Abstract
We study temporally localized structures in doubly resonant degenerate optical parametric oscillators in the absence of temporal walk-off. We focus on states formed through the locking of domain walls between the zero and a nonzero continuous-wave solution. We show that these states undergo collapsed snaking and we characterize their dynamics in the parameter space.
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Affiliation(s)
- P Parra-Rivas
- OPERA-photonics, Université libre de Bruxelles, 50 Avenue F. D. Roosevelt, CP 194/5, B-1050 Bruxelles, Belgium
- Laboratory of Dynamics in Biological Systems, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - L Gelens
- Laboratory of Dynamics in Biological Systems, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - F Leo
- OPERA-photonics, Université libre de Bruxelles, 50 Avenue F. D. Roosevelt, CP 194/5, B-1050 Bruxelles, Belgium
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25
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Dornelas V, Colombo EH, Anteneodo C. Single-species fragmentation: The role of density-dependent feedback. Phys Rev E 2019; 99:062225. [PMID: 31330753 DOI: 10.1103/physreve.99.062225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Indexed: 11/07/2022]
Abstract
Internal feedback is commonly present in biological populations and can play a crucial role in the emergence of collective behavior. To describe the temporal evolution of the distribution of a single-species population, we consider a generalization of the Fisher-KPP equation. This equation includes the elementary processes of random motion, reproduction, and, importantly, nonlocal interspecific competition, which introduces a spatial scale of interaction. In addition, we take into account feedback mechanisms in diffusion and growth processes, mimicked by power-law density dependencies. This feedback includes, for instance, anomalous diffusion, reaction to overcrowding or to the rarefaction of the population, as well as Allee-like effects. We show that, depending on the kind of feedback that takes place, the population can self-organize splitting into disconnected subpopulations, in the absence of external constraints. Through extensive numerical simulations, we investigate the temporal evolution and the characteristics of the stationary population distribution in the one-dimensional case. We discuss the crucial role that density-dependence has on pattern formation, particularly on fragmentation, which can bring important consequences to processes such as epidemic spread and speciation.
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Affiliation(s)
- V Dornelas
- Department of Physics, PUC-Rio, Rua Marquês de São Vicente, 225, 22451-900, Rio de Janeiro, Brazil
| | - E H Colombo
- IFISC (CSIC-UIB), Campus Universitat Illes Balears, 07122, Palma de Mallorca, Spain
| | - C Anteneodo
- Department of Physics, PUC-Rio, Rua Marquês de São Vicente, 225, 22451-900, Rio de Janeiro, Brazil.,Institute of Science and Technology for Complex Systems, Rio de Janeiro, Brazil
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26
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Madin EMP, Precoda K, Harborne AR, Atwood TB, Roelfsema CM, Luiz OJ. Multi-Trophic Species Interactions Shape Seascape-Scale Coral Reef Vegetation Patterns. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00102] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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27
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Ollivier QR, Hammill E, Booth DJ, Madin EMP, Hinchliffe C, Harborne AR, Lovelock CE, Macreadie PI, Atwood TB. Benthic meiofaunal community response to the cascading effects of herbivory within an algal halo system of the Great Barrier Reef. PLoS One 2018. [PMID: 29513746 PMCID: PMC5841801 DOI: 10.1371/journal.pone.0193932] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Benthic fauna play a crucial role in organic matter decomposition and nutrient cycling at the sediment-water boundary in aquatic ecosystems. In terrestrial systems, grazing herbivores have been shown to influence below-ground communities through alterations to plant distribution and composition, however whether similar cascading effects occur in aquatic systems is unknown. Here, we assess the relationship between benthic invertebrates and above-ground fish grazing across the 'grazing halos' of Heron Island lagoon, Australia. Grazing halos, which occur around patch reefs globally, are caused by removal of seagrass or benthic macroalgae by herbivorous fish that results in distinct bands of unvegetated sediments surrounding patch reefs. We found that benthic algal canopy height significantly increased with distance from patch reef, and that algal canopy height was positively correlated with the abundances of only one invertebrate taxon (Nematoda). Both sediment carbon to nitrogen ratios (C:N) and mean sediment particle size (μm) demonstrated a positive correlation with Nematoda and Arthropoda (predominantly copepod) abundances, respectively. These positive correlations indicate that environmental conditions are a major contributor to benthic invertebrate community distribution, acting on benthic communities in conjunction with the cascading effects of above-ground algal grazing. These results suggest that benthic communities, and the ecosystem functions they perform in this system, may be less responsive to changes in above-ground herbivorous processes than those previously studied in terrestrial systems. Understanding how above-ground organisms, and processes, affect their benthic invertebrate counterparts can shed light on how changes in aquatic communities may affect ecosystem function in previously unknown ways.
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Affiliation(s)
- Quinn R. Ollivier
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Faculty of Science Engineering and Built Environment, Deakin University, Melbourne, VIC, Australia
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
- * E-mail:
| | - Edward Hammill
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
- Department of Watershed Sciences and Ecology Center, Utah State University, Logan, UT, United States of America
| | - David J. Booth
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Elizabeth M. P. Madin
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- Hawai’i Institute of Marine Biology, University of Hawai’i, Kane’ohe, HI, United States of America
| | - Charles Hinchliffe
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Alastair R. Harborne
- Marine Spatial Ecology Laboratory and Australian Research Council Centre of Excellence for Coral Reef Studies, School of Biological Sciences, University of Queensland, Brisbane, QLD, Australia
- Department of Biological Sciences, Florida International University, North Miami, Florida, United States of America
| | - Catherine E. Lovelock
- Global Change Institute, University of Queensland, St. Lucia, QLD, Australia
- School of Biological Sciences University of Queensland, St. Lucia, QLD, Australia
| | - Peter I. Macreadie
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Faculty of Science Engineering and Built Environment, Deakin University, Melbourne, VIC, Australia
| | - Trisha B. Atwood
- Department of Watershed Sciences and Ecology Center, Utah State University, Logan, UT, United States of America
- Global Change Institute, University of Queensland, St. Lucia, QLD, Australia
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28
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Vilas MP, Marti CL, Adams MP, Oldham CE, Hipsey MR. Invasive Macrophytes Control the Spatial and Temporal Patterns of Temperature and Dissolved Oxygen in a Shallow Lake: A Proposed Feedback Mechanism of Macrophyte Loss. FRONTIERS IN PLANT SCIENCE 2017; 8:2097. [PMID: 29276526 PMCID: PMC5727088 DOI: 10.3389/fpls.2017.02097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 11/24/2017] [Indexed: 05/25/2023]
Abstract
Submerged macrophytes can have a profound effect on shallow lake ecosystems through their ability to modify the thermal structure and dissolved oxygen levels within the lake. Invasive macrophytes, in particular, can grow rapidly and induce thermal gradients in lakes that may substantially change the ecosystem structure and challenge the survival of aquatic organisms. We performed fine-scale measurements and 3D numerical modeling at high spatiotemporal resolution to assess the effect of the seasonal growth of Potamogeton crispus L. on the spatial and temporal dynamics of temperature and dissolved oxygen in a shallow urban lake (Lake Monger, Perth, WA, Australia). Daytime stratification developed during the growing season and was clearly observed throughout the macrophyte bed. At all times measured, stratification was stronger at the center of the macrophyte bed compared to the bed edges. By fitting a logistic growth curve to changes in plant height over time (r2 = 0.98), and comparing this curve to temperature data at the center of the macrophyte bed, we found that stratification began once the macrophytes occupied at least 50% of the water depth. This conclusion was strongly supported by a 3D hydrodynamic model fitted to weekly temperature profiles measured at four time periods throughout the growing season (r2 > 0.78 at all times). As the macrophyte height increased and stratification developed, dissolved oxygen concentration profiles changed from vertically homogeneous oxic conditions during both the day and night to expression of night-time anoxic conditions close to the sediments. Spatially interpolated maps of dissolved oxygen and 3D numerical modeling results indicated that the plants also reduced horizontal exchange with surrounding unvegetated areas, preventing flushing of low dissolved oxygen water out of the center of the bed. Simultaneously, aerial imagery showed central dieback occurring toward the end of the growing season. Thus, we hypothesized that stratification-induced anoxia can lead to accelerated P. crispus dieback in this region, causing formation of a ring-shaped pattern in spatial macrophyte distribution. Overall, our study demonstrates that submerged macrophytes can alter the thermal characteristics and oxygen levels within shallow lakes and thus create challenging conditions for maximizing their spatial coverage.
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Affiliation(s)
- Maria P. Vilas
- UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, Australia
| | - Clelia L. Marti
- Sustainable Engineering Group, Faculty of Science and Engineering, Curtin University, Bentley, WA, Australia
| | - Matthew P. Adams
- School of Chemical Engineering, University of Queensland, St Lucia, QLD, Australia
| | - Carolyn E. Oldham
- School of Civil, Environmental and Mining Engineering, University of Western Australia, Crawley, WA, Australia
| | - Matthew R. Hipsey
- UWA School of Agriculture and Environment, University of Western Australia, Crawley, WA, Australia
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29
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Fragment dispersal and plant-induced dieback explain irregular ring-shaped pattern formation in a clonal submerged macrophyte. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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