Climate change is likely to disrupt food chains by favouring animals with short lifespans over often bigger rivals that are worse at tolerating temperature swings.
Researchers in Germany and Canada say that animals have widely differing 鈥渢hermal windows鈥� 鈥� a range of temperatures in which they best feed, grow and reproduce. That means that climate change will not affect all equally.
鈥淐limate change will favour species with wide thermal windows, short lifespans and a large gene pool amongst its population,鈥� the journal Science says of the findings.
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Big fish such as cod, which have narrow thermal windows, are moving north in the Atlantic, for instance, partly because the food chain has been disrupted by a shift to smaller plankton, reducing the amount of prey on which large fish can feed.
Slower growth
A shift to smaller plankton means that juvenile cod in the Atlantic have to use more energy to feed, slowing their growth. Female cod tolerate only a narrow 鈥渢hermal window鈥� when they produce eggs, part of a strategy evolved to cut energy use.
The study focused on the oceans, but the scientists said the findings may also apply to land creatures.
鈥淓ach species covers a certain range. The ranges overlap, but their [thermal] windows are not the same,鈥� says Hans-Otto P枚rtner of the , one of the authors.
Knowledge of such differences could help predict reactions to climate change, widely blamed on human emissions of greenhouse gases from burning fossil fuels.
In the German Wadden Sea, larger eelpout fish 鈥� a long, thin species that grows to about 500 grams 鈥� suffered more quickly than smaller fish when summer temperatures rose above normal.
鈥淚n the Japan Sea, different thermal windows between sardines and anchovies 聟 caused a regime shift to anchovies in the late 1990s,鈥� the researchers say.
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