Beavers play an important role in North America and its ecology. Beaver dams provide enormous benefits for all kinds of wildlife. In the West, they are very beneficial to trout by providing slower water refuges where the fish can grow to larger sizes, thus producing more eggs and offspring. The riparian vegetation that grows in association with beaver dams also creates habitat for songbirds and other wildlife.
According to a recent find in eastern Oregon, it looks like beavers have been in North America for at least 7 to 7.3 million years.
Cattle grazing, in some cases, has eliminated beavers from entire systems because they compete with beavers for food. I’ve seen areas in the Owyhee Mountains where all of the riparian soils which would support the aspens and willows needed by beavers have washed completely away and only bedrock or large substrate remains. Reintroducing beavers to these streams would be pointless unless the streams were given years of rest from cattle grazing so that some vegetation could return to provide beavers enough food to survive and make beaver dams again.
Comments
Thanks for the article. I find beavers fascinating as well as challenging.
Reintroduction of beaver to very damaged areas has been researched by NOAA fisheries with considerable success in Oregon. Check out this video for footage http://www.opb.org/programs/ofg/segments/view/1758
This is good but one of the problems faced in very arid systems is that there isn’t anything left for the beavers to eat. The cows have eaten everything in the area. In the Owyhee stream I referred to, they would left to build their dams from juniper trees because there are no willows or aspen left.
Hmmm, why not use juniper? Beavers do a great deal of varietal feeding, not just willow and aspen, and certainly they can build with other sources. I’ve seen our beavers eat horsetail, pondweed, tules and blackberry for example. I agree that ungulate browsing can wipe them out but there is often more food sources than we realize.
While beavers can cut down and use junipers for dams, they don’t really provide much food for them. Also, the beavers are going to move to areas that are more suitable, so there is no guarantee that they’ll restore the areas with the highest need for restoration. What needs to come first in these areas is long-term rest from livestock grazing so that enough willows and riparian vegetation to support a beaver population can return. Once that happens I think you could see some significant and rapid recovery. I don’t think it can happen without that.