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Dansereau G, Barros C, Poisot T. Spatially explicit predictions of food web structure from regional-level data. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230166. [PMID: 39034704 PMCID: PMC11293859 DOI: 10.1098/rstb.2023.0166] [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: 09/16/2023] [Revised: 12/18/2023] [Accepted: 01/23/2024] [Indexed: 07/23/2024] Open
Abstract
Knowledge about how ecological networks vary across global scales is currently limited given the complexity of acquiring repeated spatial data for species interactions. Yet, recent developments in metawebs highlight efficient ways to first document possible interactions within regional species pools. Downscaling metawebs towards local network predictions is a promising approach to using the current data to investigate the variation of networks across space. However, issues remain in how to represent the spatial variability and uncertainty of species interactions, especially for large-scale food webs. Here, we present a probabilistic framework to downscale a metaweb based on the Canadian mammal metaweb and species occurrences from global databases. We investigated how our approach can be used to represent the variability of networks and communities between ecoregions in Canada. Species richness and interactions followed a similar latitudinal gradient across ecoregions but simultaneously identified contrasting diversity hotspots. Network motifs revealed additional areas of variation in network structure compared with species richness and number of links. Our method offers the potential to bring global predictions down to a more actionable local scale, and increases the diversity of ecological networks that can be projected in space. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.
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Affiliation(s)
- Gabriel Dansereau
- Département de Sciences Biologiques, Université de Montréal, Montreal, QuebecH2V 0B3, Canada
- Quebec Centre for Biodiversity Science, Montréal, QuebecH3A 1B1, Canada
| | - Ceres Barros
- Department of Forest Resources Management, University of British Columbia, Vancouver, British ColumbiaV6T 1Z4, Canada
| | - Timothée Poisot
- Département de Sciences Biologiques, Université de Montréal, Montreal, QuebecH2V 0B3, Canada
- Quebec Centre for Biodiversity Science, Montréal, QuebecH3A 1B1, Canada
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Bonnaffé W, Danet A, Leclerc C, Frossard V, Edeline E, Sentis A. The interaction between warming and enrichment accelerates food-web simplification in freshwater systems. Ecol Lett 2024; 27:e14480. [PMID: 39096032 DOI: 10.1111/ele.14480] [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: 11/13/2023] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 08/04/2024]
Abstract
Nutrient enrichment and climate warming threaten freshwater systems. Metabolic theory and the paradox of enrichment predict that both stressors independently can lead to simpler food-webs having fewer nodes, shorter food-chains and lower connectance, but cancel each other's effects when simultaneously present. Yet, these theoretical predictions remain untested in complex natural systems. We inferred the food-web structure of 256 lakes and 373 streams from standardized fish community samplings in France. Contrary to theoretical predictions, we found that warming shortens fish food-chain length and that this effect was magnified in enriched streams and lakes. Additionally, lakes experiencing enrichment exhibit lower connectance in their fish food-webs. Our study suggests that warming and enrichment interact to magnify food-web simplification in nature, raising further concerns about the fate of freshwater systems as climate change effects will dramatically increase in the coming decades.
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Affiliation(s)
- Willem Bonnaffé
- Big Data Institute, University of Oxford, Oxford, UK
- Department of Biology, University of Oxford, Oxford, UK
| | - Alain Danet
- Centre d'Ecologie et des Sciences de la Conservation, CESCO, UMR 7204, MNHN-CNRS-SU, Paris, France
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Camille Leclerc
- RECOVER, INRAE, Aix Marseille University, Aix-en-Provence, France
- Pôle R&D Écosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
| | - Victor Frossard
- Pôle R&D Écosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
- University of Savoie Mont Blanc, INRAE, CARRTEL, Thonon-les-Bains, France
| | - Eric Edeline
- DECOD (Ecosystem Dynamics and Sustainability), INRAE, Institut Agro Rennes-Angers, IFREMER, Rennes, France
| | - Arnaud Sentis
- RECOVER, INRAE, Aix Marseille University, Aix-en-Provence, France
- Pôle R&D Écosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
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Galiana N, Arnoldi JF, Mestre F, Rozenfeld A, Araújo MB. Power laws in species' biotic interaction networks can be inferred from co-occurrence data. Nat Ecol Evol 2024; 8:209-217. [PMID: 38012361 PMCID: PMC11263125 DOI: 10.1038/s41559-023-02254-y] [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: 05/08/2023] [Accepted: 10/17/2023] [Indexed: 11/29/2023]
Abstract
Inferring biotic interactions from species co-occurrence patterns has long intrigued ecologists. Yet recent research revealed that co-occurrences may not reliably represent pairwise biotic interactions. We propose that examining network-level co-occurrence patterns can provide valuable insights into community structure and assembly. Analysing ten bipartite networks of empirically sampled biotic interactions and associated species spatial distribution, we find that approximately 20% of co-occurrences correspond to actual interactions. Moreover, the degree distribution shifts from exponential in co-occurrence networks to power laws in networks of biotic interactions. This shift results from a strong interplay between species' biotic (their interacting partners) and abiotic (their environmental requirements) niches, and is accurately predicted by considering co-occurrence frequencies. Our work offers a mechanistic understanding of the assembly of ecological communities and suggests simple ways to infer fundamental biotic interaction network characteristics from co-occurrence data.
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Affiliation(s)
- Nuria Galiana
- Department of Biogeography and Global Change, National Museum of Natural Sciences, Madrid, Spain.
| | - Jean-François Arnoldi
- Centre National de la Recherche Scientifique, Experimental and Theoretical Ecology Station, Moulis, France
| | - Frederico Mestre
- Rui Nabeiro Biodiversity Chair, Mediterranean Institute for Agriculture, Environment and Development, University of Évora, Évora, Portugal
| | - Alejandro Rozenfeld
- Rui Nabeiro Biodiversity Chair, Mediterranean Institute for Agriculture, Environment and Development, University of Évora, Évora, Portugal
- INTELYMEC Group, Centro de Investigaciones en Física e Ingeniería del Centro Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires - Universidad Nacional del Centro de la Provincia de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Técnicas, Olavarría, Argentina
| | - Miguel B Araújo
- Department of Biogeography and Global Change, National Museum of Natural Sciences, Madrid, Spain
- Rui Nabeiro Biodiversity Chair, Mediterranean Institute for Agriculture, Environment and Development, University of Évora, Évora, Portugal
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Brimacombe C, Bodner K, Michalska-Smith M, Poisot T, Fortin MJ. Shortcomings of reusing species interaction networks created by different sets of researchers. PLoS Biol 2023; 21:e3002068. [PMID: 37011096 PMCID: PMC10101633 DOI: 10.1371/journal.pbio.3002068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/13/2023] [Accepted: 03/07/2023] [Indexed: 04/05/2023] Open
Abstract
Given the requisite cost associated with observing species interactions, ecologists often reuse species interaction networks created by different sets of researchers to test their hypotheses regarding how ecological processes drive network topology. Yet, topological properties identified across these networks may not be sufficiently attributable to ecological processes alone as often assumed. Instead, much of the totality of topological differences between networks-topological heterogeneity-could be due to variations in research designs and approaches that different researchers use to create each species interaction network. To evaluate the degree to which this topological heterogeneity is present in available ecological networks, we first compared the amount of topological heterogeneity across 723 species interaction networks created by different sets of researchers with the amount quantified from non-ecological networks known to be constructed following more consistent approaches. Then, to further test whether the topological heterogeneity was due to differences in study designs, and not only to inherent variation within ecological networks, we compared the amount of topological heterogeneity between species interaction networks created by the same sets of researchers (i.e., networks from the same publication) with the amount quantified between networks that were each from a unique publication source. We found that species interaction networks are highly topologically heterogeneous: while species interaction networks from the same publication are much more topologically similar to each other than interaction networks that are from a unique publication, they still show at least twice as much heterogeneity as any category of non-ecological networks that we tested. Altogether, our findings suggest that extra care is necessary to effectively analyze species interaction networks created by different researchers, perhaps by controlling for the publication source of each network.
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Affiliation(s)
- Chris Brimacombe
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Korryn Bodner
- MAP Centre for Urban Health Solutions, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Matthew Michalska-Smith
- Department of Ecology, Evolution and Behavior, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Plant Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Timothée Poisot
- Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
- Centre de la Science de la Biodiversité du Québec, Montréal, Québec, Canada
| | - Marie-Josée Fortin
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Mestre F, Rozenfeld A, Araújo MB. Human disturbances affect the topology of food webs. Ecol Lett 2022; 25:2476-2488. [PMID: 36167463 PMCID: PMC9828725 DOI: 10.1111/ele.14107] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 08/16/2022] [Accepted: 08/21/2022] [Indexed: 01/12/2023]
Abstract
Networks describe nodes connected by links, with numbers of links per node, the degree, forming a range of distributions including random and scale-free. How network topologies emerge in natural systems still puzzles scientists. Based on previous theoretical simulations, we predict that scale-free food webs are favourably selected by random disturbances while random food webs are selected by targeted disturbances. We assume that lower human pressures are more likely associated with random disturbances, whereas higher pressures are associated with targeted ones. We examine these predictions using 351 empirical food webs, generally confirming our predictions. Should the topology of food webs respond to changes in the magnitude of disturbances in a predictable fashion, consistently across ecosystems and scales of organisation, it would provide a baseline expectation to understand and predict the consequences of human pressures on ecosystem dynamics.
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Affiliation(s)
- Frederico Mestre
- ‘Rui Nabeiro’ Biodiversity Chair, MED – Mediterranean Institute for Agriculture, Environment and Development & CHANGE – Global Change and Sustainability Institute, Institute for Advanced Studies and ResearchUniversidade de ÉvoraÉvoraPortugal
| | - Alejandro Rozenfeld
- ‘Rui Nabeiro’ Biodiversity Chair, MED – Mediterranean Institute for Agriculture, Environment and Development & CHANGE – Global Change and Sustainability Institute, Institute for Advanced Studies and ResearchUniversidade de ÉvoraÉvoraPortugal,Centro de Investigaciones en Física e Ingeniería del CentroUniversidad Nacional del Centro de la Provincia de Buenos Aires, Consejo Nacional de Investigaciones Científicas y TécnicasTandilBuenos AiresArgentina,CONICET‐CIFICEN‐Universidad del Centro de la Provincia de Buenos AiresTandilBuenos AiresArgentina
| | - Miguel B. Araújo
- ‘Rui Nabeiro’ Biodiversity Chair, MED – Mediterranean Institute for Agriculture, Environment and Development & CHANGE – Global Change and Sustainability Institute, Institute for Advanced Studies and ResearchUniversidade de ÉvoraÉvoraPortugal,Department of Biogeography and Global Change, National Museum of Natural SciencesCSICMadridSpain
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