New research from Norway鈥檚 Rondane mountains shows how roads, hiking trails and human activity are breaking up the habitat of wild reindeer and disrupting ancient migration routes.
Wild reindeer in one of Norway鈥檚 best-known mountain regions are becoming increasingly isolated as roads, trails and human activity divide their habitat.
from the Norwegian Institute for Nature Research (NINA) shows that the Rondane wild reindeer area is now so fragmented that its animals effectively form four separate sub-populations.
Researchers reached the conclusion by combining GPS tracking data from wild reindeer with information about traffic and human movement through the region. In some places, the animals have stopped using traditional migration routes altogether.
Reindeer Need Room To Roam
Wild reindeer depend on being able to move between winter grazing areas, summer pastures and calving grounds.
But reindeer are highly wary of people. NINA says heavy human traffic can sometimes create a stronger barrier than the road or trail itself, preventing animals from reaching otherwise suitable habitat.
Between the northern and southern parts of Rondane, traditional reindeer movement has now virtually ceased.
Researchers found that the likelihood of an animal crossing a road or trail depends partly on how busy it is. Crossings are most likely when few people are nearby, and the animals also appear to favour daylight and moving into the wind.
The findings highlight a difficult challenge for Norway. Rondane is both an important wild reindeer habitat and a popular destination for hiking and outdoor recreation.
Increasingly Isolated Herds
When reindeer stop crossing these barriers, herds can remain on the same side for entire seasons or even throughout the year.
NINA senior researcher Brage Bremset Hansen said this probably gives the animals poorer access to important grazing areas, which over time could affect their physical condition and the number of calves that survive.
Isolation can also have longer-term genetic consequences. When animals from different parts of the population meet and reproduce less frequently, genetic exchange decreases.
That can increase the risk of inbreeding and reduce the population鈥檚 ability to adapt to future environmental changes.
Researchers caution that fragmentation is not necessarily the sole cause of negative trends already being seen in the health of Rondane鈥檚 reindeer. However, Hansen said the loss and division of habitat clearly has a negative effect.
No Simple Solution
Norwegian authorities are already planning measures intended to reopen important migration corridors and reduce disturbance in Rondane. But NINA researchers say isolated changes are unlikely to be enough.
One previous experiment involved closing the at night in an attempt to make crossings easier.
The measure lasted only a short time and produced little measurable effect, with factors such as wind direction potentially influencing whether the animals crossed.
Researchers argue that several coordinated measures will be needed and that their impact may take years to become clear.
The Rondane findings are also part of a much bigger problem. Roads, cabins, trails and other infrastructure have divided what were once connected reindeer landscapes across southern Norway into increasingly isolated areas.
For an animal whose survival strategy has long depended on moving freely through vast mountain landscapes, that loss of space is becoming increasingly difficult to ignore.
