Environment

Climate change forces reindeer to resort to eating seaweed

Climate change forces reindeer...
Photographic evidence of reindeer eating seaweed is only the beginning
Photographic evidence of reindeer eating seaweed is only the beginning
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Photographic evidence of reindeer eating seaweed is only the beginning
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Photographic evidence of reindeer eating seaweed is only the beginning

In the face of climate change, reindeer are resorting to eating kelp seaweed, according to new research. The creatures in question are Svalbard reindeer (Rangifer tarandus platyrhynchus), a sub-species of wild reindeer. As their name suggests, they're native to Svalbard, an archipelago about halfway between Norway and the North Pole. Historically, seaweed was not part of the diets of these reindeer.

The researchers' suspicions were first aroused when they saw reindeer feeding at the shore. Reindeer in the region have since been pictured eating seaweed, but the research hangs on more substantial evidence: reindeer poo, gathered from habitats both near the shore and farther inland. Isotopes of carbon, nitrogen and sulphur found in the waste confirm that seaweed has become a fixture of the reindeers' diet.

The researchers think that the change could be caused by rain associated with increasingly-frequent warmer winters. By Svalbard's standards, "warmer" is relative, of course – average winter temperatures in some parts can be as low as -20 degrees C (-4 degrees F).

The rain freezes as a layer of ice on top of the packed snow, blocking access to the reindeer's ordinary diet of moss, lichens, grass and small plants. This ground is is the same phenomenon causing the weight loss in reindeer recorded in separate research reported by New Atlas in 2016.

Svalbard reindeer are well-adapted to extremely cold conditions (Photo: Erik Ropstad)

These "ice-locked pastures," as they're called in the research, are known to cause population fluctuation in wild reindeer and caribou populations more generally. The formation of this temporary ground ice, or basal ice, should not be confused with the permanent and significant decrease of Arctic sea ice which is caused by climate change.

By combining this data GPS collar readings, recorded visual sightings and annual date on ground ice thickness, the researchers have determined that, when ground ice is thicker, reindeer make for the coast. Conversely, they don't eat kelp when they don't have to.

The reindeer don't totally switch diet, though. "It seems they can't sustain themselves on seaweed," biologist Brage Hansen explains in a press release. "They do move back and forth between the shore and the few ice-free vegetation patches every day, so it is obvious that they have to combine it with normal food, whatever they can find."

Despite this, the seaweed is taking a toll on the reindeer: diarrhea, which is thought to be caused by the salt content. If there's a silver lining, it may be the reindeer's adaptability in the face of adversity. Not all species are as fortunate.

"Although we sometimes observe that populations crash during extremely icy winters, the reindeer are surprisingly adaptive," Hansen adds. "They have different solutions for new problems like rapid climate change, they have a variety of strategies, and most are able to survive surprisingly hard conditions."

That said, the researchers are yet to examine the effect of the change in diet on the reindeer's nutritional intake.

There are some 20,000 Svalbard reindeer – the most northerly reindeer population in the world. Their portlier frame is better suited to extreme cold. They are well adapted to eating large quantities of moss, to make up for its low nutritional value.

The research was carried out by a team from the University of Alaska, the University of Aarhus in Denmark and The University Centre in Svalbard. Their research is published in the journal Ecosphere and available to read online.

The Arctic is the scene of the most rapid climate change on Earth, but the adaptability of life in the region is poorly understood. More research of this kind is needed to begin to understand the impact of climate change on biodiversity in the Arctic – and beyond.

Sources: Ecosphere, Norwegian University of Science and Technology and SINTEF

5 comments
ljaques
As the planet does its usual swing between an iceball and a much warmer place, all plants and animals (including humans) will continue to have to adapt. (You used it in your own report: well adapted.) Species which do, survive. Species which do not, do not. Millions of species have died out before, and many millions will die off in the future. Let's not be one of them by reverting to the stone age, eh? Please pass the red meat platter. I'm hungry. D*mn the cow farts. Full beef ahead!
RobertEhresman
Raindeer that can get to kelp eat kelp. Spend some time in the Aleutians, OK?
bwana4swahili
Adapt or die! These reindeer have the right idea.
earthflute
So reindeer are adapting as most species do or they don't and perish. Natural selection from their environment. Same as the polar bears who were supposed to have died out in 2015 (another Al Gore 'we are all going to die' pronouncement) coz of GW or CC, yet they are at record population levels. Earth has been warming for 200+ years now at the same rate even though co2 has gone from 280 to 480ppm. So clearly not related. Species come and species go. Humans may be the next ones to exit?
flyerfly
The notion that raindeer or carabou don't eat seaweed normally is to funny. Here in Alaska they do. I bet they even like it...they like the salty flavor like I do. Just because somebody just notices something does not mean that it is sudden or new behavior caused by "climate change". When the climate changes I put my raincoat or not...very unusual I am sure.