Climate change has minor impact on marmots for now

Climate change is causing marmots to move, but not far, according to a recent study by SLF biologist Anne Kempel. She investigated the altitude at which most marmots currently live and compared her findings with data from 1982. Her assumption was that the animals were moving to higher altitudes because of the warmer temperatures caused by climate change. “But that’s only partly true,” says the researcher.

In fact, the majority of the animal families she observed in the Dischma Valley near Davos live about 86 meters higher than they did 42 years ago, at around 2,500 meters above sea level. Kempel concludes that the conditions there are apparently ideal for marmots. “But the absolute upper limit hasn’t shifted,” she explains. This limit is 2,700 meters above sea level, as was already the case in 1982. The findings are published in Ecology and Evolution.

Habitat depends on multiple factors

“Other factors probably play a more important role than warmer temperatures,” notes Kempel. Too high up, the animals would not find any soil in which to dig their extensive burrows. In addition, during hibernation they need as thick a snowpack as possible to insulate the ground from the cold. “We find most of these conditions exactly where most groups now live,” says the biologist.

Moreover, plants containing linoleic acid are an important part of this animal’s diet. This unsaturated fatty acid regulates body temperature in winter. “These plants may have shifted their range slightly upwards,” Kempel suspects.

Kempel and her team adopted the same methods as their predecessors in 1982. For one to two hours at a time, they observed 25 areas on the slopes of the Dischma Valley using telescopes and binoculars and counted the marmots they saw. Statistical computer models then extrapolated the probable population, leading to the surprising conclusion.

Climate stress and rising treelines threaten marmots’ habitat

However, their observations only apply to the Davos region and possibly similar areas. “We don’t have historical data for other locations,” says Kempel. In lower parts of the Alps, conditions could become difficult for the animals, as they suffer from heat stress at temperatures above 25°C. They then retreat to their burrows for long periods during the day and so eat less fat for the winter—with fatal consequences in the cold season.

In the long term, this could also become a problem at higher altitudes, as it is getting warmer there too. “But the Dischma Valley still only sees an average of six days per year with temperatures above 25°, which is too few to have a negative impact,” Kempel reassures us.

Nevertheless, there is already less space, given that the treeline is slowly but steadily shifting upwards. “Marmots prefer open habitats. They aren’t suited to living in forests, and since they aren’t moving further up into the mountains, their habitat is shrinking,” explains Kempel.