“Global warming causes habitats to change or even disappear, so that animals in the Northern Hemisphere will have to move from south to north or into higher elevations, provided that the pathways the animals need to follow aren’t blocked,” says Sterling Miller, an NWF senior scientist in Missoula, Montana. “We’re already seeing warmer weather push mountain goat and American pika habitats higher and higher into alpine areas. We’re also seeing wolverines blocked from moving between patches of the deep mountain snow they use for denning and for transportation corridors.” Says Crooks, “Few are debating the need to restore and protect landscape connectivity for wildlife. The big question is: How do you achieve it?”
One way is with wildlife corridors. Also known as greenways, linkages and passageways, these tracts of habitat link two or more larger core areas. Some are naturally occurring, such as the creek bluffs along which Jakes’s pronghorn migrate. Others are made by humans, like the 42 culverts recently installed under stretches of U.S. Highway 93 on the Flathead Indian Reservation in western Montana to make the roadway permeable to wildlife. When reconstruction of the highway was being planned, the Confederated Salish and Kootenai Tribes expressed strong concerns about wildlife and habitat fragmentation impacts, disruption of movement corridors and vehicle-caused wildlife mortality.
Freedom of Movement – National Wildlife Federation.