The influence of plant growth as a result of the increasingly warm climate also appears to bring about changes in the feeding habits of herbivores.
As the Arctic warms year by year, so do concerns about the fate of Santa’s reindeer.
But, in a remote corner of the North, in Svalbard (island territory in the Arctic Ocean), Rudolf and his friends are having a hard time.
How is “ice cream on a stick” formed from blades of grass?
Warmer temperatures stimulate plant growth and give Svalbard’s reindeer more time to replenish their fat reserves. And the researchers noticed that they have also changed their diet and prefer grass that appears as an “ice cream on a stick” – that is, blades of grass grow and break through the ice and snow.
Smaller but stockier than their distant cousins in Lapland (but also impressively antlered, of course), Svalbard’s reindeer populate almost all of the non-glacial areas of the archipelago, which lies some 800 kilometers from the North Pole . And like any other arctic region, Svalbard has experienced heavy snow and sleet episodes (increasingly frequent in recent years), and this requires extra effort from the reindeer when digging in the ground for food.
Also in this context, reports of mass starvation in Russia and declining caribou populations in Alaska and Canada have also raised concerns about the fate of reindeer in Svalbard. But in the most productive area of the archipelago, the population of these herbivores seems to have increased in recent decades, according to The Guardian.
Reindeer menu, richer after global warming
To find out what led to the increase in this animal population, PhD student Tamara Hiltunen, from the University of Oulu in Finland, looked at blood samples collected in past winters, as part of another monitoring study.
So Tamara and her colleagues compared the proportions of carbon and nitrogen isotopes in these samples to infer the type of plants the reindeer were eating in the weeks before the harvest.
The result of the research showed that between 1995 and 2012, a period in which sleet had already become a normal phenomenon for the area, winter temperatures increased, but so did the number of reindeer. For the animal’s menu, this meant a shift from short grass (like moss) to tall grass (like graminoid – a species of grass with narrow, long leaves).
“The natural length of the graminoid stalk allows this forage to be available to the animals, even though we have around a centimeter of ice at ground level. Thus, they have the equivalent of an ice cream on a stick, which is nutritious enough for the animals to sustain themselves, even during the stressful times of winter,” explained Professor Jeffrey Welker, from the University of Oulu, who oversaw the research.