1
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Gibbs TL, Gellner G, Levin SA, McCann KS, Hastings A, Levine JM. When can higher-order interactions produce stable coexistence? Ecol Lett 2024; 27:e14458. [PMID: 38877741 DOI: 10.1111/ele.14458] [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: 10/17/2023] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/16/2024]
Abstract
Most ecological models are based on the assumption that species interact in pairs. Diverse communities, however, can have higher-order interactions, in which two or more species jointly impact the growth of a third species. A pitfall of the common pairwise approach is that it misses the higher-order interactions potentially responsible for maintaining natural diversity. Here, we explore the stability properties of systems where higher-order interactions guarantee that a specified set of abundances is a feasible equilibrium of the dynamics. Even these higher-order interactions which lead to equilibria do not necessarily produce stable coexistence. Instead, these systems are more likely to be stable when the pairwise interactions are weak or facilitative. Correlations between the pairwise and higher-order interactions, however, do permit robust coexistence even in diverse systems. Our work not only reveals the challenges in generating stable coexistence through higher-order interactions but also uncovers interaction patterns that can enable diversity.
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Affiliation(s)
- Theo L Gibbs
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Gabriel Gellner
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Simon A Levin
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Kevin S McCann
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Alan Hastings
- Department of Environmental Science and Policy, University of California at Davis, Davis, California, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Jonathan M Levine
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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2
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Zou HX, Yan X, Rudolf VHW. Time-dependent interaction modification generated from plant-soil feedback. Ecol Lett 2024; 27:e14432. [PMID: 38698727 DOI: 10.1111/ele.14432] [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: 11/28/2023] [Revised: 04/10/2024] [Accepted: 04/18/2024] [Indexed: 05/05/2024]
Abstract
Pairwise interactions between species can be modified by other community members, leading to emergent dynamics contingent on community composition. Despite the prevalence of such higher-order interactions, little is known about how they are linked to the timing and order of species' arrival. We generate population dynamics from a mechanistic plant-soil feedback model, then apply a general theoretical framework to show that the modification of a pairwise interaction by a third plant depends on its germination phenology. These time-dependent interaction modifications emerge from concurrent changes in plant and microbe populations and are strengthened by higher overlap between plants' associated microbiomes. The interaction between this overlap and the specificity of microbiomes further determines plant coexistence. Our framework is widely applicable to mechanisms in other systems from which similar time-dependent interaction modifications can emerge, highlighting the need to integrate temporal shifts of species interactions to predict the emergent dynamics of natural communities.
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Affiliation(s)
- Heng-Xing Zou
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, Houston, Texas, USA
| | - Xinyi Yan
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Volker H W Rudolf
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, Houston, Texas, USA
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3
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Buche L, Bartomeus I, Godoy O. Multitrophic Higher-Order Interactions Modulate Species Persistence. Am Nat 2024; 203:458-472. [PMID: 38489780 DOI: 10.1086/729222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
AbstractEcologists increasingly recognize that interactions between two species can be affected by the density of a third species. How these higher-order interactions (HOIs) affect species persistence remains poorly understood. To explore the effect of HOIs stemming from multiple trophic layers on a plant community composition, we experimentally built a mesocosm with three plants and three pollinator species arranged in a fully nested and modified network structure. We estimated pairwise interactions among plants and between plants and pollinators, as well as HOIs initiated by a plant or a pollinator affecting plant species pairs. Using a structuralist approach, we evaluated the consequences of the statistically supported HOIs on the persistence probability of each of the three competing plant species and their combinations. HOIs substantially redistribute the strength and sign of pairwise interactions between plant species, promoting the opportunities for multispecies communities to persist compared with a non-HOI scenario. However, the physical elimination of a plant-pollinator link in the modified network structure promotes changes in per capita pairwise interactions and HOIs, resulting in a single-species community. Our study provides empirical evidence of the joint importance of HOIs and network structure in determining species persistence within diverse communities.
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4
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Song C, Spaak JW. Trophic tug-of-war: Coexistence mechanisms within and across trophic levels. Ecol Lett 2024; 27:e14409. [PMID: 38590122 DOI: 10.1111/ele.14409] [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: 03/23/2023] [Revised: 02/26/2024] [Accepted: 03/06/2024] [Indexed: 04/10/2024]
Abstract
Ecological communities encompass rich diversity across multiple trophic levels. While modern coexistence theory has been widely applied to understand community assembly, its traditional formalism only allows assembly within a single trophic level. Here, using an expanded definition of niche and fitness differences applicable to multitrophic communities, we study how diversity within and across trophic levels affects species coexistence. If each trophic level is analysed separately, both lower- and higher trophic levels are governed by the same coexistence mechanisms. In contrast, if the multitrophic community is analysed as a whole, different trophic levels are governed by different coexistence mechanisms: coexistence at lower trophic levels is predominantly limited by fitness differences, whereas coexistence at higher trophic levels is predominantly limited by niche differences. This dichotomy in coexistence mechanisms is supported by theoretical derivations, simulations of phenomenological and trait-based models, and a case study of a primeval forest ecosystem. Our work provides a general and testable prediction of coexistence mechanism operating in multitrophic communities.
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Affiliation(s)
- Chuliang Song
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Jurg W Spaak
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
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5
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Wang S, Hong P, Adler PB, Allan E, Hautier Y, Schmid B, Spaak JW, Feng Y. Towards mechanistic integration of the causes and consequences of biodiversity. Trends Ecol Evol 2024:S0169-5347(24)00054-5. [PMID: 38503639 DOI: 10.1016/j.tree.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/21/2024]
Abstract
The global biodiversity crisis has stimulated decades of research on three themes: species coexistence, biodiversity-ecosystem functioning relationships (BEF), and biodiversity-ecosystem functional stability relationships (BEFS). However, studies on these themes are largely independent, creating barriers to an integrative understanding of the causes and consequences of biodiversity. Here we review recent progress towards mechanistic integration of coexistence, BEF, and BEFS. Mechanisms underlying the three themes can be linked in various ways, potentially creating either positive or negative relationships between them. That said, we generally expect positive associations between coexistence and BEF, and between BEF and BEFS. Our synthesis represents an initial step towards integrating causes and consequences of biodiversity; future developments should include more mechanistic approaches and broader ecological contexts.
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Affiliation(s)
- Shaopeng Wang
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Science, Peking University, Beijing 100871, China.
| | - Pubin Hong
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Science, Peking University, Beijing 100871, China
| | - Peter B Adler
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Eric Allan
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland; Centre for Development and Environment, University of Bern, Mittelstrasse 43, Bern 3012, Switzerland
| | - Yann Hautier
- Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Bernhard Schmid
- Remote Sensing Laboratories, Department of Geography, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Jurg W Spaak
- Landscape ecology, RPTU Kaiserslautern Landau, 76829 Landau, Germany
| | - Yanhao Feng
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
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6
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Vollert SA, Drovandi C, Adams MP. Unlocking ensemble ecosystem modelling for large and complex networks. PLoS Comput Biol 2024; 20:e1011976. [PMID: 38483981 DOI: 10.1371/journal.pcbi.1011976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 03/26/2024] [Accepted: 03/07/2024] [Indexed: 03/27/2024] Open
Abstract
The potential effects of conservation actions on threatened species can be predicted using ensemble ecosystem models by forecasting populations with and without intervention. These model ensembles commonly assume stable coexistence of species in the absence of available data. However, existing ensemble-generation methods become computationally inefficient as the size of the ecosystem network increases, preventing larger networks from being studied. We present a novel sequential Monte Carlo sampling approach for ensemble generation that is orders of magnitude faster than existing approaches. We demonstrate that the methods produce equivalent parameter inferences, model predictions, and tightly constrained parameter combinations using a novel sensitivity analysis method. For one case study, we demonstrate a speed-up from 108 days to 6 hours, while maintaining equivalent ensembles. Additionally, we demonstrate how to identify the parameter combinations that strongly drive feasibility and stability, drawing ecological insight from the ensembles. Now, for the first time, larger and more realistic networks can be practically simulated and analysed.
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Affiliation(s)
- Sarah A Vollert
- Centre for Data Science, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Christopher Drovandi
- Centre for Data Science, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Matthew P Adams
- Centre for Data Science, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Chemical Engineering, The University of Queensland, St Lucia, Australia
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7
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Di Martino R, Picot A, Mitri S. Oxidative stress changes interactions between 2 bacterial species from competitive to facilitative. PLoS Biol 2024; 22:e3002482. [PMID: 38315734 PMCID: PMC10881020 DOI: 10.1371/journal.pbio.3002482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 02/21/2024] [Accepted: 12/22/2023] [Indexed: 02/07/2024] Open
Abstract
Knowing how species interact within microbial communities is crucial to predicting and controlling community dynamics, but interactions can depend on environmental conditions. The stress-gradient hypothesis (SGH) predicts that species are more likely to facilitate each other in harsher environments. Even if the SGH gives some intuition, quantitative modeling of the context-dependency of interactions requires understanding the mechanisms behind the SGH. In this study, we show with both experiments and a theoretical analysis that varying the concentration of a single compound, linoleic acid (LA), modifies the interaction between 2 bacterial species, Agrobacterium tumefaciens and Comamonas testosteroni, from competitive at a low concentration, to facilitative at higher concentrations where LA becomes toxic for one of the 2 species. We demonstrate that the mechanism behind facilitation is that one species is able to reduce reactive oxygen species (ROS) that are produced spontaneously at higher concentrations of LA, allowing for short-term rescue of the species that is sensitive to ROS and longer coexistence in serial transfers. In our system, competition and facilitation between species can occur simultaneously, and changing the concentration of a single compound can alter the balance between the two.
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Affiliation(s)
- Rita Di Martino
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Aurore Picot
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Sara Mitri
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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8
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Chen Y, Gel YR, Marathe MV, Poor HV. A simplicial epidemic model for COVID-19 spread analysis. Proc Natl Acad Sci U S A 2024; 121:e2313171120. [PMID: 38147553 PMCID: PMC10769830 DOI: 10.1073/pnas.2313171120] [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: 08/02/2023] [Accepted: 11/11/2023] [Indexed: 12/28/2023] Open
Abstract
Networks allow us to describe a wide range of interaction phenomena that occur in complex systems arising in such diverse fields of knowledge as neuroscience, engineering, ecology, finance, and social sciences. Until very recently, the primary focus of network models and tools has been on describing the pairwise relationships between system entities. However, increasingly more studies indicate that polyadic or higher-order group relationships among multiple network entities may be the key toward better understanding of the intrinsic mechanisms behind the functionality of complex systems. Such group interactions can be, in turn, described in a holistic manner by simplicial complexes of graphs. Inspired by these recently emerging results on the utility of the simplicial geometry of complex networks for contagion propagation and armed with a large-scale synthetic social contact network (also known as a digital twin) of the population in the U.S. state of Virginia, in this paper, we aim to glean insights into the role of higher-order social interactions and the associated varying social group determinants on COVID-19 propagation and mitigation measures.
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Affiliation(s)
- Yuzhou Chen
- Department of Computer and Information Sciences, Temple University, Philadelphia, PA19122
| | - Yulia R. Gel
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, TX75080
- Division of Mathematical Sciences, NSF, Alexandria, VA22314
| | - Madhav V. Marathe
- Department of Computer Science, University of Virginia
- Biocomplexity Institute and Initiative, University of Virginia, Charlottesville, VA22904
| | - H. Vincent Poor
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ08544
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9
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Zou HX, Rudolf VHW. Bridging theory and experiments of priority effects. Trends Ecol Evol 2023; 38:1203-1216. [PMID: 37633727 DOI: 10.1016/j.tree.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/28/2023]
Abstract
Priority effects play a key role in structuring natural communities, but considerable confusion remains about how they affect different ecological systems. Synthesizing previous studies, we show that this confusion arises because the mechanisms driving priority and the temporal scale at which they operate differ among studies, leading to divergent outcomes in species interactions and biodiversity patterns. We suggest grouping priority effects into two functional categories based on their mechanisms: frequency-dependent priority effects that arise from positive frequency dependence, and trait-dependent priority effects that arise from time-dependent changes in interacting traits. Through easy quantification of these categories from experiments, we can construct community models representing diverse biological mechanisms and interactions with priority effects, therefore better predicting their consequences across ecosystems.
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Affiliation(s)
- Heng-Xing Zou
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, 6100 Main St, Houston, TX 77005, USA.
| | - Volker H W Rudolf
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, 6100 Main St, Houston, TX 77005, USA
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10
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Sadiq FA, De Reu K, Steenackers H, Van de Walle A, Burmølle M, Heyndrickx M. Dynamic social interactions and keystone species shape the diversity and stability of mixed-species biofilms - an example from dairy isolates. ISME COMMUNICATIONS 2023; 3:118. [PMID: 37968339 PMCID: PMC10651889 DOI: 10.1038/s43705-023-00328-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 10/28/2023] [Accepted: 11/02/2023] [Indexed: 11/17/2023]
Abstract
Identifying interspecies interactions in mixed-species biofilms is a key challenge in microbial ecology and is of paramount importance given that interactions govern community functionality and stability. We previously reported a bacterial four-species biofilm model comprising Stenotrophomonas rhizophila, Bacillus licheniformis, Microbacterium lacticum, and Calidifontibacter indicus that were isolated from the surface of a dairy pasteuriser after cleaning and disinfection. These bacteria produced 3.13-fold more biofilm mass compared to the sum of biofilm masses in monoculture. The present study confirms that the observed community synergy results from dynamic social interactions, encompassing commensalism, exploitation, and amensalism. M. lacticum appears to be the keystone species as it increased the growth of all other species that led to the synergy in biofilm mass. Interactions among the other three species (in the absence of M. lacticum) also contributed towards the synergy in biofilm mass. Biofilm inducing effects of bacterial cell-free-supernatants were observed for some combinations, revealing the nature of the observed synergy, and addition of additional species to dual-species combinations confirmed the presence of higher-order interactions within the biofilm community. Our findings provide understanding of bacterial interactions in biofilms which can be used as an interaction-mediated approach for cultivating, engineering, and designing synthetic bacterial communities.
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Affiliation(s)
- Faizan Ahmed Sadiq
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090, Melle, Belgium.
| | - Koen De Reu
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090, Melle, Belgium
| | - Hans Steenackers
- Centre of Microbial and Plant Genetics (CMPG), Department of Microbial and Molecular Systems, KU Leuven, Kasteelpark Arenberg 20, 3001, Leuven, Belgium
| | - Ann Van de Walle
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090, Melle, Belgium
| | - Mette Burmølle
- Section of Microbiology, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - Marc Heyndrickx
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Technology and Food Science Unit, Brusselsesteenweg 370, 9090, Melle, Belgium.
- Ghent University, Department of Pathobiology, Pharmacology and Zoological Medicine, Salisburylaan 133, B-9820, Merelbeke, Belgium.
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11
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Allen-Perkins A, García-Callejas D, Bartomeus I, Godoy O. Structural asymmetry in biotic interactions as a tool to understand and predict ecological persistence. Ecol Lett 2023; 26:1647-1662. [PMID: 37515408 DOI: 10.1111/ele.14291] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 06/29/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023]
Abstract
A universal feature of ecological systems is that species do not interact with others with the same sign and strength. Yet, the consequences of this asymmetry in biotic interactions for the short- and long-term persistence of individual species and entire communities remains unclear. Here, we develop a set of metrics to evaluate how asymmetric interactions among species translate to asymmetries in their individual vulnerability to extinction under changing environmental conditions. These metrics, which solve previous limitations of how to independently quantify the size from the shape of the so-called feasibility domain, provide rigorous advances to understand simultaneously why some species and communities present more opportunities to persist than others. We further demonstrate that our shape-related metrics are useful to predict short-term changes in species' relative abundances during 7 years in a Mediterranean grassland. Our approach is designed to be applied to any ecological system regardless of the number of species and type of interactions. With it, we show that is possible to obtain both mechanistic and predictive information on ecological persistence for individual species and entire communities, paving the way for a stronger integration of theoretical and empirical research.
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Affiliation(s)
- Alfonso Allen-Perkins
- Departamento de Ingeniería Eléctrica, Electrónica, Automática y Física Aplicada, ETSIDI, Technical University of Madrid, Madrid, Spain
| | - David García-Callejas
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Landcare Research, Lincoln, New Zealand
| | | | - Oscar Godoy
- Departamento de Biología, Instituto Universitario de Ciencias del Mar (INMAR), Universidad de Cádiz, Puerto Real, Spain
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12
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Han BA, Varshney KR, LaDeau S, Subramaniam A, Weathers KC, Zwart J. A synergistic future for AI and ecology. Proc Natl Acad Sci U S A 2023; 120:e2220283120. [PMID: 37695904 PMCID: PMC10515155 DOI: 10.1073/pnas.2220283120] [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] [Indexed: 09/13/2023] Open
Abstract
Research in both ecology and AI strives for predictive understanding of complex systems, where nonlinearities arise from multidimensional interactions and feedbacks across multiple scales. After a century of independent, asynchronous advances in computational and ecological research, we foresee a critical need for intentional synergy to meet current societal challenges against the backdrop of global change. These challenges include understanding the unpredictability of systems-level phenomena and resilience dynamics on a rapidly changing planet. Here, we spotlight both the promise and the urgency of a convergence research paradigm between ecology and AI. Ecological systems are a challenge to fully and holistically model, even using the most prominent AI technique today: deep neural networks. Moreover, ecological systems have emergent and resilient behaviors that may inspire new, robust AI architectures and methodologies. We share examples of how challenges in ecological systems modeling would benefit from advances in AI techniques that are themselves inspired by the systems they seek to model. Both fields have inspired each other, albeit indirectly, in an evolution toward this convergence. We emphasize the need for more purposeful synergy to accelerate the understanding of ecological resilience whilst building the resilience currently lacking in modern AI systems, which have been shown to fail at times because of poor generalization in different contexts. Persistent epistemic barriers would benefit from attention in both disciplines. The implications of a successful convergence go beyond advancing ecological disciplines or achieving an artificial general intelligence-they are critical for both persisting and thriving in an uncertain future.
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Affiliation(s)
| | - Kush R. Varshney
- IBM Research - Thomas J. Watson Research Center, Yorktown Heights, NY10598
| | | | - Ajit Subramaniam
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY10964
| | | | - Jacob Zwart
- U.S. Geological Survey, Water Resources Mission Area, Integrated Information Dissemination Division, San Francisco, CA94116
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13
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Luo C, Zwicker D. Influence of physical interactions on spatiotemporal patterns. Phys Rev E 2023; 108:034206. [PMID: 37849174 DOI: 10.1103/physreve.108.034206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/31/2023] [Indexed: 10/19/2023]
Abstract
Spatiotemporal patterns are often modeled using reaction-diffusion equations, which combine complex reactions between constituents with ideal diffusive motion. Such descriptions neglect physical interactions between constituents, which might affect resulting patterns. To overcome this, we study how physical interactions affect cyclic dominant reactions, like the seminal rock-paper-scissors game, which exhibits spiral waves for ideal diffusion. Generalizing diffusion to incorporate physical interactions, we find that weak interactions change the length- and time scales of spiral waves, consistent with a mapping to the complex Ginzburg-Landau equation. In contrast, strong repulsive interactions typically generate oscillating lattices, and strong attraction leads to an interplay of phase separation and chemical oscillations, like droplets co-locating with cores of spiral waves. Our work suggests that physical interactions are relevant for forming spatiotemporal patterns in nature, and it might shed light on how biodiversity is maintained in ecological settings.
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Affiliation(s)
- Chengjie Luo
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
| | - David Zwicker
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
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14
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Shen C, Lemmen K, Alexander J, Pennekamp F. Connecting higher-order interactions with ecological stability in experimental aquatic food webs. Ecol Evol 2023; 13:e10502. [PMID: 37693938 PMCID: PMC10483096 DOI: 10.1002/ece3.10502] [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: 05/09/2023] [Revised: 07/11/2023] [Accepted: 08/22/2023] [Indexed: 09/12/2023] Open
Abstract
Community ecology is built on theories that represent the strength of interactions between species as pairwise links. Higher-order interactions (HOIs) occur when a species changes the pairwise interaction between a focal pair. Recent theoretical work has highlighted the stabilizing role of HOIs for large, simulated communities, yet it remains unclear how important higher-order effects are in real communities. Here, we used experimental communities of aquatic protists to examine the relationship between HOIs and stability (as measured by the persistence of a species in a community). We cultured a focal pair of consumers in the presence of additional competitors and a predator and collected time series data of their abundances. We then fitted competition models with and without HOIs to measure interaction strength between the focal pair across different community compositions. We used survival analysis to measure the persistence of individual species. We found evidence that additional species positively affected persistence of the focal species and that HOIs were present in most of our communities. However, persistence was only linked to HOIs for one of the focal species. Our results vindicate community ecology theory positing that species interactions may deviate from assumptions of pairwise interactions, opening avenues to consider possible consequences for coexistence and stability.
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Affiliation(s)
- Chenyu Shen
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
- Department of Environmental Systems ScienceInstitute for Integrative Biology, Swiss Federal Institute of TechnologyZurichSwitzerland
| | - Kimberley Lemmen
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Jake Alexander
- Department of Environmental Systems ScienceInstitute for Integrative Biology, Swiss Federal Institute of TechnologyZurichSwitzerland
| | - Frank Pennekamp
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
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15
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Song C, Simmons BI, Fortin MJ, Gonzalez A, Kaiser-Bunbury CN, Saavedra S. Rapid monitoring of ecological persistence. Proc Natl Acad Sci U S A 2023; 120:e2211288120. [PMID: 37155860 PMCID: PMC10194002 DOI: 10.1073/pnas.2211288120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 03/29/2023] [Indexed: 05/10/2023] Open
Abstract
Effective conservation of ecological communities requires accurate and up-to-date information about whether species are persisting or declining to extinction. The persistence of an ecological community is supported by its underlying network of species interactions. While the persistence of the network supporting the whole community is the most relevant scale for conservation, in practice, only small subsets of these networks can be monitored. There is therefore an urgent need to establish links between the small snapshots of data conservationists can collect, and the "big picture" conclusions about ecosystem health demanded by policymakers, scientists, and societies. Here, we show that the persistence of small subnetworks (motifs) in isolation-that is, their persistence when considered separately from the larger network of which they are a part-is a reliable probabilistic indicator of the persistence of the network as a whole. Our methods show that it is easier to detect if an ecological community is not persistent than if it is persistent, allowing for rapid detection of extinction risk in endangered systems. Our results also justify the common practice of predicting ecological persistence from incomplete surveys by simulating the population dynamics of sampled subnetworks. Empirically, we show that our theoretical predictions are supported by data on invaded networks in restored and unrestored areas, even in the presence of environmental variability. Our work suggests that coordinated action to aggregate information from incomplete sampling can provide a means to rapidly assess the persistence of entire ecological networks and the expected success of restoration strategies.
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Affiliation(s)
- Chuliang Song
- Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, QCH3A 0G4, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ONM5S 3B2, Canada
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ08544
| | - Benno I. Simmons
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, PenrynTR10 9FE, United Kingdom
| | - Marie-Josée Fortin
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ONM5S 3B2, Canada
| | - Andrew Gonzalez
- Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, QCH3A 0G4, Canada
| | | | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA02138
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Blonder BW, Lim MH, Sunberg Z, Tomlin C. Navigation between initial and desired community states using shortcuts. Ecol Lett 2023; 26:516-528. [PMID: 36756862 DOI: 10.1111/ele.14171] [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: 04/11/2022] [Accepted: 01/10/2023] [Indexed: 02/10/2023]
Abstract
Ecological management problems often involve navigating from an initial to a desired community state. We ask whether navigation without brute-force additions and deletions of species is possible via: adding/deleting a small number of individuals of a species, changing the environment, and waiting. Navigation can yield direct paths (single sequence of actions) or shortcut paths (multiple sequences of actions with lower cost than a direct path). We ask (1) when is non-brute-force navigation possible?; (2) do shortcuts exist and what are their properties?; and (3) what heuristics predict shortcut existence? Using a state diagram framework applied to several empirical datasets, we show that (1) non-brute-force navigation is only possible between some state pairs, (2) shortcuts exist between many state pairs; and (3) changes in abundance and richness are the strongest predictors of shortcut existence, independent of dataset and algorithm choices. State diagrams thus unveil hidden strategies for manipulating species coexistence and efficiently navigating between states.
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Affiliation(s)
- Benjamin W Blonder
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California, USA
| | - Michael H Lim
- Department of Electrical Engineering and Computer Science, University of California Berkeley, Berkeley, California, USA
| | - Zachary Sunberg
- Aerospace Engineering Sciences Department, University of Colorado Boulder, Boulder, Colorado, USA
| | - Claire Tomlin
- Department of Electrical Engineering and Computer Science, University of California Berkeley, Berkeley, California, USA
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