Wednesday, October 7, 2020

Beavers


There has been a considerable amount of scientific and on-the-ground research since the previous post on Re-Beavification.  This topic was met with tremendous skepticism, and outright scorn from some during the development of the Ventura River Watershed Plan.  However, new information lends credence to the idea that re-introduction of beaver to the watershed could provide significant benefits and even resolve some of the ongoing conflict over water supply.

There is a growing understanding of the concept of "slow it, spread it, sink it" as a tool in protecting and improving groundwater resources.   In general this applies to our land management practices, where shifting away from impervious "pave it and drain it" practices helps put water back in the ground.  But just as important, we should consider how past changes in our rivers and creeks have also impacted the amount of water stored underground.  

In this video, National Forest hydrologist Kami Elison explains the benefits of "Living with Beaver"


 

Are Beavers native to the Ventura River?

Many do not realize that before the "Gold Rush" trappers scoured every nook and cranny of the state during the "California Fur Rush."  Of course the nearby Channel Islands was a treasure trove of fur seals and sea otters, but trappers also went up the rivers for beaver.  This is described in this wikipedia article on the history of beavers in California.  As part of their Bring Back the Beaver CampaignKate Lundquist and Brock Dolman co-authored The Historical Range of Beaver in Coastal California, a peer-reviewed scientific paper re-evaluating the historic evidence of beaver on the coast of California. Ventura County is included in this research.

Why are Beavers important?

Beavers are nature's engineer, and their removal from our coastal rivers had a drastic effect on the ecosystem.  North American beaver (Castor canadensis) are what biologists call a “keystone species” as the habitat they create benefits many other species. Their dams improve water quantity and quality, increase late season flow and reduce the impacts of flooding. Beaver bank burrows and food caches provide critical habitat for many native and endangered California species. 

Here is what the Water Institute of the Occidental Art and Ecology Center has to say:

“Extensive research has recently heightened recognition of the important role beaver (Castor canadensis) can play in watershed health and climate change resiliency. The species’ ecological services include enhanced water storage, erosion control, habitat restoration and creation, listed species recovery, the maintenance of stream flows during the dry summer period, and other beneficial adaptations to our changing climate conditions."

Despite these benefits, current California beaver policy solely focuses on recreational hunting and lethal nuisance management. In response, the WATER Institute launched a Bring Back the Beaver Campaign to educate citizens about the importance of beaver. In order to improve water supply for humans and the environment and increase resilience to drought and climate change, we are working to integrate their management into California policy and regulation.

In addition to the resources on OAEC's site, the Beaver Institute has a large library of technical reference on everything from biodiversity and climate change, to experiments with man-made "Beaver Dam Analogs" that have been demonstrated to restore streams.  

Interestingly, visitors to the Ventura River have shown a tireless propensity for building pools in which to cool off in the hot months.  These human dams may in fact be a form of Beaver Dam Analog, slowing the flow, and perhaps even helping to increase our precious groundwater supply. 

Ventura River "Beaver Dam Analog" (BDA)


Below is a list of references and articles for those interested in learning more:

Bring Back the BeaverOccidental Art and Ecology Center

Beaver Institute

Keep Me Wild: Beaver:  California Department of Fish and Wildlife 

 'We became beavers' US Fish and Wildlife Service Partnering with the Scott River Watershed Council, designed a project to simulate what beavers had not been around to do for decades

Role of Beaver in Stream Ecosystems: Overview of beaver life history and habitat requirements, presentation from NOAA Northwest Fisheries Science Center

Why Beavers are Worth a Dam!  Environmental Protection Information Center (EPIC) advocates for statewide beaver relocation program

Beavers—Once Nearly Extinct—Could Help Fight Climate Change National Geographic; Beaver ponds keep rivers and streams wet all year, compensating for less snowpack and glacial melt. We just need to stay out of their way.

The Bountiful Benefits Of Bringing Back The Beavers, NPR Weekend Edition

Bring Back The Beavers  article includes video "How Beavers Engineer the Land" 

The Martinez Beavers: Worth A Dam