A wildlife overpass in Banff national park, in the Canadian Rockies. Photograph: Ross MacDonald/Banff National Park

Protecting wilderness–for broad reasons related to the value of biodiversity as well more narrow reasons related to mankind’s  basic requirements–have been a constant theme on this platform since we started; animal bridges, per se, have not. Here is a look at why these bridges matter:

How creating wildlife crossings can help reindeer, bears – and even crabs

Sweden’s announcement this week that it is to build a series of animal bridges is the latest in global efforts to help wildlife navigate busy roads

Reindeer viaducts in Sweden will keep herds safe from traffic as they roam in search of grazing. Photograph: Pawel Garski./Alamy

Every April, Sweden’s main highway comes to a periodic standstill. Hundreds of reindeer overseen by indigenous Sami herders shuffle across the asphalt on the E4 as they begin their journey west to the mountains after a winter gorging on the lichen near the city of Umeå. As Sweden’s main arterial road has become busier, the crossings have become increasingly fractious, especially if authorities do not arrive in time to close the road. Sometimes drivers try to overtake the reindeer as they cross – spooking the animals and causing long traffic jams as their Sami owners battle to regain control.

“During difficult climate conditions, these lichen lands can be extra important for the reindeer,” says Per Sandström, a landscape ecologist at the Swedish University of Agricultural Sciences who works as an intermediary between the Sami and authorities to improve the crossings.

This week, Swedish authorities announced they would build up to a dozen “renoducts” (reindeer viaducts) to aid the crossings and allow reindeer herds to reach grazing more easily.

It is hoped the crossings will allow herders to find fresh grazing lands and alleviate traffic jams, and also help moose and lynx to move around the landscape. The country’s 4,500 Sami herders and 250,000 reindeer have been hit hard by the climate crisis, battling forest fires in the summer and freezing rain in the winter that hides lichen below impenetrable sheets of ice…

Read the whole story here.