Marmots prefer open environments, they do not adapt to the forest.
Keystone / Sigi Tischler
Marmots today live an average of 86 meters higher than 40 years ago, according to a study carried out in the Dischma valley, near Davos (GR). Their living space is reduced, because their absolute upper limit has not moved: these animals do not exceed 2700 meters above sea level.
Marmots migrate due to climate change, but not far away. This is what emerges from the study conducted by Anne Kempel, biologist at the WSL Institute for the study of snow and avalanches (SLF) and published in the journal Ecology and Evolution. The Institute specifies that their habitat is not fundamentally modified due to climate change.
The researcher studied the altitude at which the marmots live mainly at present and compared her results to data dating from 1982. Results: the majority of families of animals she observed in the Dischma valley, near Davos, live around 86 meters higher than 42 years ago, at around 2500 meters above sea level.
“But the absolute upper limit has not moved,” said the scientist, quoted Tuesday in a SLF press release. It stops at an altitude of 2700 m. This was already the case in 1982. “Other factors undoubtedly play a greater role than higher temperatures,” notes Anne Kempel. Too high, animals would not find a soil in which to dig their very branched burrows.
Need a floor to dig, snow and certain plants
During their hibernation, the marmots need a layer of snow as thick as possible to isolate the soil of the cold. “This is precisely where most of the groups live today that we find the maximum of these parameters,” according to the biologist. Added to this is the fact that plants containing linoleic acid constitute an important element of food.
This unsaturated fatty acid regulates body temperature in winter. However, “these plants may have slightly moved their range to the heights,” supposes Anne Kempel.
Thermal stress from 25 degrees
Anne Kempel and her team used the same methods as their predecessors in 1982. For one to two hours, they observed 25 areas on the slopes of the Dischma valley using binoculars and a long view and counted the groundhogs. IT statistical models then extrapolated the likely population of marmots and reached this result.
However, its observation only applies to the Davos region and possibly comparable areas. In the lower parts of the Alps, the situation could however become difficult for these animals. Indeed, from 25 degrees, the marmots suffer from thermal stress.
In the Dischma valley, there are still on average only six days a year with more than 25 degrees, which is too little to have negative effects. The situation has nevertheless already tightened, because the limit of the forest rises slowly but surely. “However, marmots prefer open environments, they do not adapt to the forest and as they cannot go higher, their living space is reduced,” concludes Anne Kempel.
