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Research article2012Peer reviewedOpen access

Predator transitory spillover induces trophic cascades in ecological sinks

Casini M, Blenckner T, Moellmann C, Gardmark A, Lindegren M, Llope M, Kornilovs G, Plikshs M, Stenseth NC

Abstract

Understanding the effects of cross-system fluxes is fundamental in ecosystem ecology and biological conservation. Source-sink dynamics and spillover processes may link adjacent ecosystems by movement of organisms across system boundaries. However, effects of temporal variability in these cross-system fluxes on a whole marine ecosystem structure have not yet been presented. Here we show, using 35 y of multitrophic data series from the Baltic Sea, that transitory spillover of the top-predator cod from its main distribution area produces cascading effects in the whole food web of an adjacent and semi-isolated ecosystem. At varying population size, cod expand/contract their distribution range and invade/retreat from the neighboring Gulf of Riga, thereby affecting the local prey population of herring and, indirectly, zooplankton and phytoplankton via top-down control. The Gulf of Riga can be considered for cod a "true sink" habitat, where in the absence of immigration from the source areas of the central Baltic Sea the cod population goes extinct due to the absence of suitable spawning grounds. Our results add a metaecosystem perspective to the ongoing intense scientific debate on the key role of top predators in structuring natural systems. The integration of regional and local processes is central to predict species and ecosystem responses to future climate changes and ongoing anthropogenic disturbances.

Keywords

ecosystem regulation; predator distribution; landscape ecology; exploited resources; cross-system management

Published in

Proceedings of the National Academy of Sciences
2012, Volume: 109, number: 21, pages: 8185-8189

      SLU Authors

      • Sustainable Development Goals

      SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss
      SDG14 Conserve and sustainably use the oceans, seas and marine resources for sustainable development
      SDG13 Take urgent action to combat climate change and its impacts

      UKÄ Subject classification

      Ecology

      Publication identifier

      DOI: https://doi.org/10.1073/pnas.1113286109

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/42814