How do food-webs respond to climate change?

Monday 04 Dec 17


Ken Haste Andersen
Professor, Head of Section
DTU Aqua
+45 35 88 33 99

To understand the effects of climate change on changing ocean biomass, understanding how different species interact is a difficult but necessary task.

"We have reason to believe that species in a state of nature are limited in their ranges by the competition of other organic beings quite as much as, or more than, by adaptation to particular climates". Such wrote Darwin one and a half century ago.  He was right -- see our new paper on climate change in a food-web context in Proc. Roy Soc. L. B (post print here).  We show that species interactions — competition and predation — are more important processes than the increasing temperatures: apparently warm-adapted species are equally likely to be affected by climate change than cold-adapted species.  Therefore, unfortunately, the effects of climate change cannot be predicted by the direct effects of temperature alone. In most cases we must account for changes in competitors and predators, which are much harder to predict.

The figure above shows the development of food-webs under climate change. Each dot represents a species, and the colour shows its preferred temperature.  The solid circles are species that are established in the food-web, and the lines represents their strength of interaction.  As the temperature in the environment increases, some species may go extinct, or new species may invade (only in the left panel).  Consequently, the structure of the food-web changes.

See the paper here.

Zhang L, Takahashi D, Hartvig M, Andersen KH. 2017 Food-web dynamics under climate change. Proc. R. Soc. B 284: 20171772.
21 MAY 2018