Direct and indirect climate forcing in a multi-species marine system

Interactions within and between species complicate quantification of climate effects, by causing indirect, often delayed, effects of climate fluctuations and compensation of mortality. Here we identify direct and indirect climate effects by analysing unique Russian time-series data from the Norwegia...

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Bibliographic Details
Published in:Proceedings of the Royal Society B: Biological Sciences
Main Authors: Ottersen, Geir, Stige, Leif Christian, Dalpadado, Padmini, Chan, Kung-Sik, Hjermann, Dag Ø., Lajus, Dmitry L., Yaragina, Natalia A., Stenseth, Nils Christian
Format: Article in Journal/Newspaper
Language:English
Published: Royal Society Publishing 2010
Subjects:
økosystemdynamikk
ecosystem dynamics
dyreplankton
zooplankton
populasjonsdynamikk
population dynamics
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488
Barents Sea
Norwegian Sea
Online Access:http://hdl.handle.net/11250/108472
https://doi.org/10.1098/rspb.2010.0602
Description
Summary:Interactions within and between species complicate quantification of climate effects, by causing indirect, often delayed, effects of climate fluctuations and compensation of mortality. Here we identify direct and indirect climate effects by analysing unique Russian time-series data from the Norwegian Sea–Barents Sea ecosystem on the first life stages of cod, capelin, herring and haddock, their predators, competitors and zooplanktonic prey. By analysing growth and survival from one life stage to the next (eggs–larvae– juveniles–recruits), we find evidence for both bottom-up, direct and top-down effects of climate. Ambient zooplankton biomass predicts survival of all species, whereas ambient temperature mainly affects survival through effects on growth. In warm years, all species experienced improved growth and feeding conditions. Cohorts born following a warm year will, however, experience increased predation and competition because of increased densities of subadult cod and herring, leading to delayed climate effects. While climate thus affects early growth and survival through several mechanisms, only some of the identified mechanisms were found to be significant predictors of population growth. In particular, our findings exemplify that climate impacts are barely propagated to later life stages when density dependence is strong.

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