Wildlife officials dropped 240 beavers into dying Pacific Northwest streams—and the ecosystem response was anything but expected. The rodents were meant to restore degraded waterways, rebuilding dams that had vanished for a century.
In the mountains of Washington state, biologists have spent more than a decade moving beavers into streams that were losing water. The animals, once considered pests, have rebuilt wetlands, stored millions of gallons of water, cooled rivers for salmon, and created natural firebreaks across dry landscapes.The work began in 2007 in the Methow Valley, where streams feeding the Eastern Cascade Mountai…