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Majer A, Skoracka A, Spaak J, Kuczyński L. Higher-order species interactions cause time-dependent niche and fitness differences: Experimental evidence in plant-feeding arthropods. Ecol Lett 2024; 27:e14428. [PMID: 38685715 DOI: 10.1111/ele.14428] [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: 06/19/2023] [Revised: 03/25/2024] [Accepted: 04/04/2024] [Indexed: 05/02/2024]
Abstract
Species interact in different ways, including competition, facilitation and predation. These interactions can be non-linear or higher order and may depend on time or species densities. Although these higher-order interactions are virtually ubiquitous, they remain poorly understood, as they are challenging both theoretically and empirically. We propose to adapt niche and fitness differences from modern coexistence theory and apply them to species interactions over time. As such, they may not merely inform about coexistence, but provide a deeper understanding of how species interactions change. Here, we investigated how the exploitation of a biotic resource (plant) by phytophagous arthropods affects their interactions. We performed monoculture and competition experiments to fit a generalized additive mixed model to the empirical data, which allowed us to calculate niche and fitness differences. We found that species switch between different types of interactions over time, including intra- and interspecific facilitation, and strong and weak competition.
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Affiliation(s)
- Agnieszka Majer
- Population Ecology Lab, Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland
- Center for Advanced Technology, Adam Mickiewicz University, Poznań, Poland
| | - Anna Skoracka
- Population Ecology Lab, Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland
| | - Jürg Spaak
- Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Lechosław Kuczyński
- Population Ecology Lab, Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland
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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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Aguadé-Gorgorió G, Arnoldi JF, Barbier M, Kéfi S. A taxonomy of multiple stable states in complex ecological communities. Ecol Lett 2024; 27:e14413. [PMID: 38584579 DOI: 10.1111/ele.14413] [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: 10/23/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/09/2024]
Abstract
Natural systems are built from multiple interconnected units, making their dynamics, functioning and fragility notoriously hard to predict. A fragility scenario of particular relevance concerns so-called regime shifts: abrupt transitions from healthy to degraded ecosystem states. An explanation for these shifts is that they arise as transitions between alternative stable states, a process that is well-understood in few-species models. However, how multistability upscales with system complexity remains a debated question. Here, we identify that four different multistability regimes generically emerge in models of species-rich communities and other archetypical complex biological systems assuming random interactions. Across the studied models, each regime consistently emerges under a specific interaction scheme and leaves a distinct set of fingerprints in terms of the number of observed states, their species richness and their response to perturbations. Our results help clarify the conditions and types of multistability that can be expected to occur in complex ecological communities.
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Affiliation(s)
| | - Jean-François Arnoldi
- Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS and Paul Sabatier University, Moulis, France
| | - Matthieu Barbier
- PHIM Plant Health Institute, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Sonia Kéfi
- ISEM, Univ Montpellier, CNRS, IRD, Montpellier, France
- France Santa Fe Institute, Santa Fe, New Mexico, USA
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Lepori VJ, Loeuille N, Rohr RP. Robustness versus productivity during evolutionary community assembly: short-term synergies and long-term trade-offs. Proc Biol Sci 2024; 291:20232495. [PMID: 38196359 PMCID: PMC10777152 DOI: 10.1098/rspb.2023.2495] [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: 11/06/2023] [Accepted: 12/07/2023] [Indexed: 01/11/2024] Open
Abstract
The realization that evolutionary feedbacks need to be considered to fully grasp ecological dynamics has sparked interest in the effect of evolution on community properties like coexistence and productivity. However, little is known about the evolution of community robustness and productivity along diversification processes in species-rich systems. We leverage the recent structural approach to coexistence together with adaptive dynamics to study such properties and their relationships in a general trait-based model of competition on a niche axis. We show that the effects of coevolution on coexistence are two-fold and contrasting depending on the time scale considered. In the short term, evolution of niche differentiation strengthens coexistence, while long-term diversification leads to niche packing and decreased robustness. Moreover, we find that coevolved communities tend to be on average more robust and more productive than non-evolutionary assemblages. We illustrate how our theoretical predictions echo in observed empirical patterns and the implications of our results for empiricists and applied ecologists. We suggest that some of our results such as the improved robustness of Evolutionarily Stable Communities could be tested experimentally in suitable model systems.
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Affiliation(s)
- Vasco J. Lepori
- Department of Biology – Ecology and Evolution, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Nicolas Loeuille
- Institute of Ecology and Environmental Sciences, IEES, Sorbonne Université, UPEC, CNRS, IRD, INRA, 75005 Paris, France
| | - Rudolf P. Rohr
- Department of Biology – Ecology and Evolution, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
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Spaak JW, Schreiber SJ. Building modern coexistence theory from the ground up: The role of community assembly. Ecol Lett 2023; 26:1840-1861. [PMID: 37747362 DOI: 10.1111/ele.14302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/06/2023] [Accepted: 08/12/2023] [Indexed: 09/26/2023]
Abstract
Modern coexistence theory (MCT) is one of the leading methods to understand species coexistence. It uses invasion growth rates-the average, per-capita growth rate of a rare species-to identify when and why species coexist. Despite significant advances in dissecting coexistence mechanisms when coexistence occurs, MCT relies on a 'mutual invasibility' condition designed for two-species communities but poorly defined for species-rich communities. Here, we review well-known issues with this component of MCT and propose a solution based on recent mathematical advances. We propose a clear framework for expanding MCT to species-rich communities and for understanding invasion resistance as well as coexistence, especially for communities that could not be analysed with MCT so far. Using two data-driven community models from the literature, we illustrate the utility of our framework and highlight the opportunities for bridging the fields of community assembly and species coexistence.
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Affiliation(s)
- Jurg W Spaak
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Institute for Environmental Sciences, Rheinland-Pfälzische Technische Univerität Kaiserslautern-Landau, Landau, Germany
| | - Sebastian J Schreiber
- Department of Evolution and Ecology and Center for Population Biology, University of California, Davis, California, USA
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Spaak JW, Adler PB, Ellner SP. Mechanistic Models of Trophic Interactions: Opportunities for Species Richness and Challenges for Modern Coexistence Theory. Am Nat 2023; 202:E1-E16. [PMID: 37384764 DOI: 10.1086/724660] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
AbstractMany potential mechanisms promote species coexistence, but we know little about their relative importance. To compare multiple mechanisms, we modeled a two-trophic planktonic food web based on mechanistic species interactions and empirically measured species traits. We simulated thousands of possible communities under realistic and altered interaction strengths to assess the relative importance of three potential drivers of phytoplankton and zooplankton species richness: resource-mediated coexistence mechanisms, predator-prey interactions, and trait trade-offs. Next, we computed niche and fitness differences of competing zooplankton to obtain a deeper understanding of how these mechanisms determine species richness. We found that predator-prey interactions were the most important driver of phytoplankton and zooplankton species richness and that large zooplankton fitness differences were associated with low species richness, but zooplankton niche differences were not associated with species richness. However, for many communities we could not apply modern coexistence theory to compute niche and fitness differences of zooplankton because of conceptual issues with the invasion growth rates arising from trophic interactions. We therefore need to expand modern coexistence theory to fully investigate multitrophic-level communities.
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Native diversity contributes to composition heterogeneity of exotic floras. Ecosphere 2023. [DOI: 10.1002/ecs2.4452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
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West R, Shnerb NM. Quantitative Characteristics of Stabilizing and Equalizing Mechanisms. Am Nat 2022; 200:E160-E173. [DOI: 10.1086/720665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Pande J, Shnerb NM. How temporal environmental stochasticity affects species richness: destabilization, neutralization and the storage effect. J Theor Biol 2022; 539:111053. [DOI: 10.1016/j.jtbi.2022.111053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 01/16/2022] [Accepted: 02/02/2022] [Indexed: 10/19/2022]
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