National parks are the backbone of conservation. Yet mounting evidence shows that many are too small to sustain long-term viable populations. A new study analyzed the value of establishing ecological corridors for large mammals between Yellowstone and Glacier National Parks and between Mount Rainier and North Cascades National Parks. Findings show that these corridors would not only enlarge populations, but also allow species to shift their geographic ranges more readily in response to climate change.National parks are the backbone of conservation. Yet mounting evidence shows that many are too small to sustain long-term viable populations. A new study analyzed the value of establishing ecological corridors for large mammals between Yellowstone and Glacier National Parks and between Mount Rainier and North Cascades National Parks. Findings show that these corridors would not only enlarge populations, but also allow species to shift their geographic ranges more readily in response to climate change.