In Sweden, where the temperature is rising more than twice as fast as the global average, it’s getting harder for native reindeer to survive. One challenge is finding food in the winter: As warmer weather means that rain sometimes mixes with snow, the ground becomes icy, so the animals can no longer dig down through the powder to reach the lichens that they need to eat. Because they have to travel farther in search of better pastures, they often have to cross busy roads—and that’s why the Swedish government is building a set of reindeer bridges to help them move safely.
Climate change is only one of the challenges the animals face. “It’s a combination of increasing land-use pressures from forestry, energy, mining, and infrastructure development and a changing climate that together makes the situation so hard to deal with,” says Per Sandström, a landscape ecologist at the Swedish University of Agricultural Sciences. Intensive forestry means that there are fewer old trees where lichens grow. Forests are becoming more and more fragmented. Climate change has also led to drought and devastating wildfires in northern Sweden.
Sandström and other scientists worked with the Indigenous reindeer herders who manage the animals, moving long distances across the land in the animals’ natural grazing patterns, and identified the best places for reindeer overpasses. (They’re called “renoducts,” a play on the Swedish word for reindeer and “viaduct.”) One passage will soon be built over a major north-south highway.
In other parts of the world, similar bridges are being used for other species—like a massive crossing near Los Angeles designed to help mountain lions get over a 10-lane freeway. The bridges aren’t always a success; one built to help squirrels cross a Dutch highway didn’t turn out to be popular with the squirrels. The designers must carefully consider how to make animals feel comfortable crossing. But the bridges can be crucial, as in the case of the reindeer. “Without functioning overpasses, critical winter grazing areas with some of the last remaining lichen lands, especially important during difficult winters, would become inaccessible,” Sandström says.