Stige Leif Christian
No Thumbnail Available
Now showing 1 - 2 of 2
PreprintPredator-prey interactions cause apparent competition between marine zooplankton groups( 2017-12) Stige, Leif Christian ; Kvile, Kristina Øie ; Bogstad, Bjarte ; Langangen, ØysteinPredator-mediated apparent competition is an indirect negative interaction between two prey species mediated by a shared predator. Quantifying such indirect ecosystem effects is methodologically challenging but important for understanding ecosystem functioning. Still, there are few examples of apparent competition from pelagic marine environments. Using state-space statistical modelling, we here provide evidence for apparent competition between two dominant zooplankton groups in a large marine ecosystem, i.e., krill and copepods in the Barents Sea. This effect is mediated by a positive association between krill biomass and survival of the main planktivorous fish in the Barents Sea, capelin Mallotus villosus, and a negative association between capelin and copepod biomasses. The biomass of Atlantic krill species is expected to increase in the Barents Sea due to ongoing climate change, thereby potentially negatively affecting copepods through apparent competition. By demonstrating and quantifying apparent competition in a large marine ecosystem, our study paves the way for more realistic projections of indirect ecosystem effects of climate change and harvesting.
PreprintClimate warming drives large-scale changes in ecosystem function( 2017-10) Stige, Leif Christian ; Kvile, Kristina ØieThe Barents Sea is the continental shelf sea to the north of Scandinavia and Northwest Russia and supports some of the richest fisheries in Europe. Until recently, the northern Barents Sea was dominated by small-sized, slow-growing fish species with specialized diets, mostly living in close association with the sea floor. Concomitant with rising sea temperatures and retreating sea ice, these fishes are being replaced by fast-growing, large-bodied generalists moving in from the south.