The map above, published by scientists in 2004, shows the extent to which the ranges of 14 large mammal species have shrunk over the past 200 years and where they remain.
As western North America was settled and human activities came to dominate the region, the amount of available wildlife habitat shrank dramatically.
The Yellowstone to Yukon region (outlined in black in the map) remains a stronghold for large ungulates, such as elk and moose, and carnivores, including bear, lynx and wolverine.
As one of the last intact mountain regions in the world, whose current network of protected lands supports healthy wildlife populations, the Yellowstone to Yukon region is a refuge for these important animals.
Conserving this region is critical for the long-term survival of all wild creatures.
More about connectivity
Study and map:
Andrea S. Laliberte and William J. Ripple 2004. Range Contractions of North American Carnivores and Ungulates. BioScience 54 (2): 123-138