Understanding Biological Corridors

Little more than a century ago, most of the Northern Rockies was a vast, unbroken wilderness: wildlife roamed freely across the entire region. By the early years of this century, however, agriculture and growing towns occupied most of the valley bottoms--prime winter habitat for many wildlife species--while logging and mining roads crisscrossed the hillsides. Dams blocked crucial spawning routes for salmon and trout. Wildlife populations plummeted as wildlands were splintered into small, isolated blocks. Scientists believe that habitat loss due to fragmentation and isolation--which impedes wildlife movement and alters local climate and cover--is the major cause of extinction.

The areas most threatened by fragmentation in the Wild Rockies are also the most important to the health of wildlife and plant populations: the biological corridors connecting the region's five core ecosystems. Individually, none of these ecosystems are large enough to support self-sustaining populations of wildlife; they are dependent on each other for new and varied genetic stock. Wildlands between ecosystems serve as biological bridges, permitting migration and genetic interchange of both plants and wildlife. Without these corridors, populations will inbreed and species vigor will diminish.

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Alliance for the Wild Rockies
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