Over the last 20 years, Oregon’s wilderness has suffered big time. Salmon have disappeared, wildfires have scoured the hills and drought has parched once-fertile soils. Years of small fixes — a little forest thinning here, a little fish-ladder installation there — have helped, but not nearly enough to keep up with the destruction.

By the start of the 2020s, Oregon had more ecologically impaired waterways than almost any other state, and environmentalists were ready for a serious solution. Something bold and risky. Something that would dramatically resculpt the landscape — and potentially correct decades of human development. In a word: beavers.

Hundreds of millions of beavers called North America home until an insatiable European fur trade nearly drove them to extinction in the 1800s. As a result, waterways in the U.S. became much easier to control: They followed increasingly predictable channels, drained more quickly and left plenty of dry, stable land in their wake. That was great for human development — but bad for almost everything else.

In recent decades, lands across the West have been drying out quickly as sponge-like wetlands vanish — a result of drought, climate change and a dearth of beavers on the landscape. Without deep pools to store cold water, average stream temperatures have risen, resulting in steep declines in local fish populations, particularly salmon. Another problem: Many species of salmon require slow-moving water and protected ponds to lay their eggs and raise their young.

By the mid-1990s, several species of salmon — once a primary food source for Oregon’s Indigenous tribes and a significant economic driver in the Pacific Northwest — had been listed as endangered.

Around that time, scientists started to look for solutions, launching a frantic effort to figure out what, exactly, salmon needed — and what they were missing. A handful of Oregon State University scientists stumbled upon a clue: They discovered that regions with beaver ponds had vastly higher salmon productivity than those without. Further studies have echoed those findings.

“Beaver ponds and alcoves represented only about nine percent of the habitat but accounted for 66 percent of the coho salmon found in the system,” land managers later wrote in Oregon’s Beaver Restoration Guidebook. Another study from British Columbia showed that the survival rate for young coho salmon that overwintered behind beaver dams was 60 percent or more — significantly higher than the regional average.

Read the full article about beavers' importance to wetland ecosystems by Corey Buhay at Reasons to Be Cheerful.