Department Aquatic Ecology

Spatio-temporal dynamics in meta-ecosystem ecology

Temporal fluctuations are ubiquitous in ecological systems, shaping how organisms and ecosystems function across multiple scales. Yet ecological theory has long relied on steady-state assumptions, treating ecosystems as static entities governed by equilibrium dynamics. Emerging evidence suggests that variability in time is not simply background noise but a fundamental driver of ecological characteristics, such as community composition, biomass structure, or functions. While the effects of temporal variability have been studied at local and individual levels, its implications for meta-ecosystem dynamics remain poorly understood.

Our group aims to develop our understanding of meta-ecosystem dynamics through a combination of mathematical models and experiments. We develop mathematical models and use protist experiments to make and test predictions on the impacts of temporal and spatial fluctuations on (meta)ecosystems, modifying biodiversity and ecosystem functions in a changing world. Further, we include spatial connections between ecosystems via flows of resources and organisms (such as crustaceans) in these temporally fluctuating ecosystems. We are interested in studying the timing between ecological events.

Key Publications

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      authors => protected'Peller, T.; Gounand, I.; Altermatt, F.' (53 chars)
      title => protected'Resource flow network structure drives metaecosystem function' (61 chars)
      journal => protected'American Naturalist' (19 chars)
      year => protected2024 (integer)
      volume => protected204 (integer)
      issue => protected'6' (1 chars)
      startpage => protected'546' (3 chars)
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      categories => protected'degree distribution; ecosystem dynamics; nonlinear averaging; nutrient cycli
         ng; scaling up; spatial flows' (105 chars)
      description => protected'Nonliving resources frequently flow across ecosystem boundaries, which can y
         ield networks of spatially coupled ecosystems. Yet the significance of resou
         rce flows for ecosystem function has predominantly been understood by studyi
         ng two or a few coupled ecosystems, overlooking the broader resource flow ne
         twork and its spatial structure. Here, we investigate how the spatial struct
         ure of larger resource flow networks influences ecosystem function at metaec
         osystem scales by analyzing metaecosystem models with homogeneously versus h
         eterogeneously distributed resource flow networks but otherwise identical ch
         aracteristics. We show that metaecosystem function can differ strongly betwe
         en metaecosystems with contrasting resource flow networks. Differences in fu
         nction generally arise through the scaling up of nonlinear local processes i
         nteracting with spatial variation in local dynamics, the latter of which is 
         influenced by network structure. However, we find that neither network struc
         ture guarantees the greatest metaecosystem function. Rather, biotic (organis
         m traits) and abiotic (resource flow rates) properties interact with network
          structure to determine which yields greater metaecosystem function. Our fin
         dings suggest that the spatial structure of resource flow networks coupling 
         ecosystems can be a driver of ecosystem function at landscape scales. Furthe
         rmore, our study demonstrates how modifications to the structural, biotic, o
         r abiotic properties of metaecosystem networks can have nontrivial large-sca
         le effects on ecosystem function.' (1553 chars)
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      authors => protected'Gounand, I.; Little, C. J.; Harvey, E.; Altermatt, 
         F.' (78 chars)
      title => protected'Cross-ecosystem carbon flows connecting ecosystems worldwide' (60 chars)
      journal => protected'Nature Communications' (21 chars)
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      startpage => protected'4825 (8 pp.)' (12 chars)
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      description => protected'Ecosystems are widely interconnected by spatial flows of material, but the o
         verall importance of these flows relative to local ecosystem functioning rem
         ains unclear. Here we provide a quantitative synthesis on spatial flows of c
         arbon connecting ecosystems worldwide. Cross-ecosystem flows range over eigh
         t orders of magnitude, bringing between 10<sup>−3</sup> and 10<sup>5</sup>
          gC m<sup>−2</sup> year<sup>−1</sup> to recipient ecosystems. Magn
         itudes are similar to local fluxes in freshwater and benthic ecosystems, but
          two to three orders of magnitude lower in terrestrial systems, demonstratin
         g different dependencies on spatial flows among ecosystem types. The strong 
         spatial couplings also indicate that ecosystems are vulnerable to alteration
         s of cross-ecosystem flows. Thus, a reconsideration of ecosystem functioning
         , including a spatial perspective, is urgently needed.' (890 chars)
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      doi => protected'10.1038/s41467-018-07238-2' (26 chars)
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      title => protected'Meta-Ecosystems 2.0: rooting the theory into the field' (54 chars)
      journal => protected'Trends in Ecology and Evolution' (31 chars)
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      description => protected'The meta-ecosystem framework demonstrates the significance of among-ecosyste
         m spatial flows for ecosystem dynamics and has fostered a rich body of theor
         y. The high level of abstraction of the models, however, impedes application
         s to empirical systems. We argue that further understanding of spatial dynam
         ics in natural systems strongly depends on dense exchanges between field and
          theory. From empiricists, more and specific quantifications of spatial flow
         s are needed, defined by the major categories of organismal movement (disper
         sal, foraging, life-cycle, and migration). In parallel, the theoretical fram
         ework must account for the distinct spatial scales at which these naturally 
         common spatial flows occur. Integrating all levels of spatial connections am
         ong landscape elements will upgrade and unify landscape and meta-ecosystem e
         cology into a single framework for spatial ecology.' (887 chars)
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Resource flow network structure drives metaecosystem function

Nonliving resources frequently flow across ecosystem boundaries, which can yield networks of spatially coupled ecosystems. Yet the significance of resource flows for ecosystem function has predominantly been understood by studying two or a few coupled ecosystems, overlooking the broader resource flow network and its spatial structure. Here, we investigate how the spatial structure of larger resource flow networks influences ecosystem function at metaecosystem scales by analyzing metaecosystem models with homogeneously versus heterogeneously distributed resource flow networks but otherwise identical characteristics. We show that metaecosystem function can differ strongly between metaecosystems with contrasting resource flow networks. Differences in function generally arise through the scaling up of nonlinear local processes interacting with spatial variation in local dynamics, the latter of which is influenced by network structure. However, we find that neither network structure guarantees the greatest metaecosystem function. Rather, biotic (organism traits) and abiotic (resource flow rates) properties interact with network structure to determine which yields greater metaecosystem function. Our findings suggest that the spatial structure of resource flow networks coupling ecosystems can be a driver of ecosystem function at landscape scales. Furthermore, our study demonstrates how modifications to the structural, biotic, or abiotic properties of metaecosystem networks can have nontrivial large-scale effects on ecosystem function.
Peller, T.; Gounand, I.; Altermatt, F. (2024) Resource flow network structure drives metaecosystem function, American Naturalist, 204(6), 546-560, doi:10.1086/732812, Institutional Repository

Cross-ecosystem carbon flows connecting ecosystems worldwide

Ecosystems are widely interconnected by spatial flows of material, but the overall importance of these flows relative to local ecosystem functioning remains unclear. Here we provide a quantitative synthesis on spatial flows of carbon connecting ecosystems worldwide. Cross-ecosystem flows range over eight orders of magnitude, bringing between 10−3 and 105 gC m−2 year−1 to recipient ecosystems. Magnitudes are similar to local fluxes in freshwater and benthic ecosystems, but two to three orders of magnitude lower in terrestrial systems, demonstrating different dependencies on spatial flows among ecosystem types. The strong spatial couplings also indicate that ecosystems are vulnerable to alterations of cross-ecosystem flows. Thus, a reconsideration of ecosystem functioning, including a spatial perspective, is urgently needed.
Gounand, I.; Little, C. J.; Harvey, E.; Altermatt, F. (2018) Cross-ecosystem carbon flows connecting ecosystems worldwide, Nature Communications, 9, 4825 (8 pp.), doi:10.1038/s41467-018-07238-2, Institutional Repository

Meta-Ecosystems 2.0: rooting the theory into the field

The meta-ecosystem framework demonstrates the significance of among-ecosystem spatial flows for ecosystem dynamics and has fostered a rich body of theory. The high level of abstraction of the models, however, impedes applications to empirical systems. We argue that further understanding of spatial dynamics in natural systems strongly depends on dense exchanges between field and theory. From empiricists, more and specific quantifications of spatial flows are needed, defined by the major categories of organismal movement (dispersal, foraging, life-cycle, and migration). In parallel, the theoretical framework must account for the distinct spatial scales at which these naturally common spatial flows occur. Integrating all levels of spatial connections among landscape elements will upgrade and unify landscape and meta-ecosystem ecology into a single framework for spatial ecology.
Gounand, I.; Harvey, E.; Little, C. J.; Altermatt, F. (2018) Meta-Ecosystems 2.0: rooting the theory into the field, Trends in Ecology and Evolution, 33(1), 36-46, doi:10.1016/j.tree.2017.10.006, Institutional Repository

Contact

Prof. Dr. Florian Altermatt Tel. +41 58 765 5592 Send Mail
Lara Chaouat PhD Student Tel. Send Mail

Collaboration

Dr. Tianna Peller, University of Toronto

Further Information

www.altermattlab.ch