Randy Boswell, Postmedia News

A Canadian-led team of researchers experimenting with temperature changes endured by stickleback fish has observed “one of the fastest evolutionary responses” to cold ever witnessed by scientists.

In a finding that fuels hope for nature’s ability to cope with episodes of rapid climate change, the researchers documented how some of the fish — collected in B.C. in both freshwater lakes and ocean habitats — were able to survive in water 2.5 C colder than their grandparents’ natural habitat.

“Our study is the first to experimentally show that certain species in the wild could adapt to climate change very rapidly — in this case, colder water temperature,” said University of British Columbia zoologist Rowan Barrett.

Along with fellow UBC researchers Timothy Healy, Patricia Schulte and Dolph Schluter, as well as University of Calgary biologist Sean Rogers and colleagues from Switzerland and Sweden, Barrett chose to study the temperature tolerance of threespine sticklebacks because of the species’ well-known adaptation from warmer ocean waters to freshwater lakes at the end of the last Ice Age about 10,000 years ago.

Their study, published in the latest issue of the Proceedings of the Royal Society B, is described in a summary as having “recreated history” by transplanting wild, ocean-dwelling sticklebacks into freshwater ponds and comparing their responses to cooler temperatures with those of lake-dwelling sticklebacks.

The saltwater sticklebacks, known for their ability to adapt to freshwater settings, were also acclimatized to the experimental environment through gradual reductions in salinity levels. A significant percentage of the marine sticklebacks were able to successfully adapt to the colder setting “in as little as three generations” — or just three years.

“Scientific models have suggested that climate change could result in both a general, gradual increase of average temperatures and an increase in extreme temperatures,” Barrett stated.

He noted that while the stickleback experiments proved that some wildlife can handle relatively abrupt changes in climate, “this rapid adaptation is not achieved without a cost.”

While certain individuals “possess the ability to tolerate rapid changes” and live on, Barrett said “the number of survivors may not be large enough to sustain the population. It is crucial that knowledge of evolutionary processes is incorporated into conservation and management policy.


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