Beavers

Did you know the beavers (Castor canadensis) of the Mokelumne River don’t build dams? The river is too wide and deep, so they dig burrows into the riverbanks instead. These burrows compact soil, reduce erosion, and encourage vegetation growth, helping to stabilize the banks. By feeding on tree bark, shrubs, and aquatic plants, beavers naturally manage vegetation. Their burrowing and feeding create wetland habitats that support diverse wildlife, highlighting their essential role as ecosystem engineers.

Look across the river — those big boulders, or “armored banks,” were added by the winery to block beaver burrows. While burrows don’t significantly weaken banks, the rocks reflect waves back into the river, eroding this side's bank instead, an undesirable impact.

Beavers were nearly driven to extinction during the early 1800’s "California fur rush" because of their dense, water-resistant fur. Trapping by companies like the Hudson’s Bay Company, who used the pelts for luxury hats, decimated their population. By the early 1900’s, 99.8% of the beavers in North America had been killed, but their numbers have rebounded and they are no longer threatened. This highlights why it is crucial to provide as much habitat for beavers and other native rodents in this watershed ecosystem.