Fisheriescanhavealargeimpactonmarineecosystems,because the effects of removing large predatory fish may cascade down the food web. The implications of these cascading processes on system functioning and resilience remain a source of intense scientific debate. By using field data covering a 30-year period, we show for the Baltic Sea that the underlying mechanisms of trophiccascadesproducedashiftinecosystemfunctioningafter the collapse of the top predator cod. We identified an ecological threshold, corresponding to a planktivore abundance of 17 1010 individuals, that separates 2 ecosystem configurations in which zooplankton dynamics are driven by either hydroclimatic forces or predation pressure. Abundances of the planktivore sprat above the threshold decouple zooplankton dynamics from hydrological circumstances. The current strong regulation by sprat of the feeding resources for larval cod may hinder cod recovery and the return of the ecosystem to a prior state. This calls for the inclusion of a food web perspective in management decisions.
Casini, M., Hjelm, J., Molinero, ., Jc, ., Lövgren, J., Cardinale, M., et al. (2009). Trophic cascades promote threshold-like shifts in pelagic marine ecosystems. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 106, 197-202 [10.1073/pnas.0806649105].
Trophic cascades promote threshold-like shifts in pelagic marine ecosystems
Casini M
;
2009
Abstract
Fisheriescanhavealargeimpactonmarineecosystems,because the effects of removing large predatory fish may cascade down the food web. The implications of these cascading processes on system functioning and resilience remain a source of intense scientific debate. By using field data covering a 30-year period, we show for the Baltic Sea that the underlying mechanisms of trophiccascadesproducedashiftinecosystemfunctioningafter the collapse of the top predator cod. We identified an ecological threshold, corresponding to a planktivore abundance of 17 1010 individuals, that separates 2 ecosystem configurations in which zooplankton dynamics are driven by either hydroclimatic forces or predation pressure. Abundances of the planktivore sprat above the threshold decouple zooplankton dynamics from hydrological circumstances. The current strong regulation by sprat of the feeding resources for larval cod may hinder cod recovery and the return of the ecosystem to a prior state. This calls for the inclusion of a food web perspective in management decisions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
