Cascade-Siskiyou National Monument

This monument was specifically set aside to protect and recover the area’s unique display of plant and animal species and varied ecosystems. The history of exploitation has left its mark, but we are hopeful that remaining pockets of biodiversity are sufficient to make recovery possible.

This planning project will emphasize two types of engagement with beaver: first, supporting existing populations that could use an assist, and second, encouraging the natural expansion of beaver populations into areas where we know they used to be, where their engineering skills could return perennial flow to the parched landscape, creating the vast wetlands that all of the other species depend upon.

In the first phase of this project, we used remote modeling and on-the-ground surveying to map areas with “high intrinsic potential habitat,” meaning, areas that fit the criteria to potentially host robust beaver populations, but for various reasons aren’t, due to things like habitat degradation, a lack of food, incised stream channels, or a lack of building materials to create the dams and lodges that protect them from predators. Those are what we call “limiting factors” in that they are preventing beaver from repopulating an area, even if dispersing juveniles waddle by and try. From those data, we can build out a restoration plan that engages and removes those limiting factors. We can set the stage for beaver by planting native riparian vegetation and by implementing low-tech, process-based stream restoration techniques such as Post Assisted Log Structures (PALS) and Beaver Dam Analogues (BDAs). If necessary, we may also translocate beavers from low in the valley to areas of the monument they may have a hard time finding on their own, as they’ve been absent so long, but it is preferred to let them explore and make their life as they best see fit.