August 12, 2010

Fish evolve in response to climate change

Biologist Sean Rogers studies the ability of small fish to adapt to climate change in a pond on the U of C campus. Photo credit: Riley BrandtA tiny fish can adapt to severe temperature changes, such as those anticipated with climate change, according to University of Calgary biologist Sean Rogers.

A new study published this month in the Proceedings of the Royal Society B by Rogers and colleagues at the University of British Columbia and in Sweden and Switzerland demonstrates that the threespine stickleback—a fish native to much of northern Europe, northern Asia and North America—is able to adapt to changes in temperature over a remarkably short period of time. In as little as three years, the stickleback developed a tolerance for water temperature 2.5 degrees Celsius lower than its ancestors.

The researchers say their findings indicate that the species of minnow-like fish that was first discovered in Alberta in 1980 should be able to respond to the increasingly severe temperature extremes expected to be caused by global climate change.

“This is the first instance that this has been documented in nature in a vertebrate species,” says Rogers, Alberta Ingenuity assistant professor in the Department of Biological Sciences.

He says species faced with environmental challenges will have to move or adapt to changing temperatures in order to survive.

“What we found is that this little fish has sufficient genetic variation to permit this kind of rapid evolution in cases where the environment is going to change. We literally documented evolution in real time, in just three generations we saw this remarkable shift in the ability of these organisms to tolerate colder temperatures,” says Rogers.

The threespine stickleback fish are tiny, between 3 and 10 centimetres long.
Photo credit: Rowan BarrettHe is conducting further research into the ability of other species of fish to adapt to climate change in experimental ponds on the University of Calgary campus.

Co-author Rowan Barrett, who recently received his PhD at the University of British Columbia, says the study offers an unprecedented estimate of the rate of evolution of temperature tolerance in a natural population.

“Our study provides the first experimental evidence that a natural population can adapt to changes in temperature of magnitude similar to those expected to occur under climate change, suggesting that evolution may help populations to survive the effects of climate change," says Barrett.

“The 2.5 °C shift in temperature tolerance is among the fastest rates of phenotypic evolution to be recorded in a natural population,” he says.

While the study advances the understanding of the evolutionary consequences of climate change, the authors caution it does not mean there are no negative consequences for a species that adapts to a change in temperature. The rapid shift could result in changes to population and ecological dynamics, which could in turn negatively affect the population’s persistence.