A cross-scale trophic cascade from large predatory fish to algae in coastal ecosystems

Donadi, S., Austin, A. N., Bergstrom, U., Eriksson, B. K., Hansen, J. P., Jacobson, P., Sundblad, G., van Regteren, M. & Eklof, J. S. 26-Jul-2017 In : Proceedings of the Royal Society of London. Series B, Biological Sciences. 284, 1859, p. 1-10 10 p., 20170045

Research output: Scientific - peer-reviewArticle

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  • A cross-scale trophic cascade from large predatory fish to algae in coastal ecosystems

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  • S. Donadi
  • A. N. Austin
  • U. Bergstrom
  • B. K. Eriksson
  • J. P. Hansen
  • P. Jacobson
  • G. Sundblad
  • M. van Regteren
  • J. S. Eklof

Trophic cascades occur in many ecosystems, but the factors regulating them are still elusive. We suggest that an overlooked factor is that trophic interactions (TIs) are often scale-dependent and possibly interact across spatial scales. To explore the role of spatial scale for trophic cascades, and particularly the occurrence of cross-scale interactions (CSIs), we collected and analysed food-web data from 139 stations across 32 bays in the Baltic Sea. We found evidence of a four-level trophic cascade linking TIs across two spatial scales: at bay scale, piscivores (perch and pike) controlled mesopredators (three-spined stickleback), which in turn negatively affected epifaunal grazers. At station scale (within bays), grazers on average suppressed epiphytic algae, and indirectly benefitted habitat-forming vegetation. Moreover, the direction and strength of the grazer-algae relationship at station scale depended on the piscivore biomass at bay scale, indicating a cross-scale interaction effect, potentially caused by a shift in grazer assemblage composition. In summary, the trophic cascade from piscivores to algae appears to involve TIs that occur at, but also interact across, different spatial scales. Considering scale-dependence in general, and CSIs in particular, could therefore enhance our understanding of trophic cascades.

Original languageEnglish
Article number20170045
Pages (from-to)1-10
Number of pages10
JournalProceedings of the Royal Society of London. Series B, Biological Sciences
Issue number1859
StatePublished - 26-Jul-2017


  • trophic cascade, cross-scale interaction, piecewise structural equation model, algal bloom, piscivorous fish, Baltic Sea, LAND-UPLIFT BAYS, TOP-DOWN CONTROL, BALTIC SEA, FOOD-WEB, NUTRIENT ENRICHMENT, RELATIVE IMPORTANCE, SPATIAL-PATTERNS, BIODIVERSITY, DYNAMICS, PREY

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