Beavers: Nature’s Ecological Restoration Agents
By Heidi Perryman & Michael Callahan / By Timothy Sexauer

Photo by Cheryl Reynolds/ Worth A Dam

The many benefits of beavers

By Heidi Perryman & Michael Callahan

Most people only become aware of beavers when they are a nuisance, but did you know that biologists classify beavers as a Keystone species? Beaver ponds create wetlands which are among the most biologically productive ecosystems in the world. They increase plant, bird and wildlife variety, improve water quality, and raise salmon and trout populations. This one species supports thousands.

How is this possible? By opening the tree canopy, sunlight reaches the water and triggers an explosion of biological activity. Algae and aquatic plants grow in the sun drenched, nutrient rich water. This organic material supports microscopic organisms, which are eaten by a variety of invertebrates. These become food for fish, birds and mammals. An entire food chain is created in a beaver pond.

While infamous for killing trees, beaver dams actually create diverse habitats. Grasses, sedges, bushes and saplings grow on the perimeter of the pond. These plants provide food and cover for foraging animals.

Beaver ponds become magnets for a rich variety of wildlife. From important game species like wood duck, mink and otter, to vulnerable anadromous fish like rainbow smelt, steelhead and salmon, biodiversity thrives due to beaver ponds. Beaver dams also protect downstream spawning areas from sedimentation, and create cool, deep pools which increase salmon and trout populations.

Photo by Cheryl Reynolds/ Worth A Dam

How do dams affect water quality? They actually improve flow and quality. By functioning as natural sponges that store runoff water and slowly release it, they reduce downstream flooding and erosion. The algae, plants and sediment in the pond improve water quality by absorbing dissolved nutrients, processing organic wastes, and removing runoff toxins (e.g. heavy metals, pesticides and fertilizers) from the water. These wetlands serve as the “Earth’s Kidneys”.

Beaver ponds also recharge our drinking water aquifers, stabilize the water table, and better maintain stream flows during droughts. Beavers are now being relocated by states throughout the west to improve arid lands.

 

While they are sometimes regarded as pests, the in truth there isn’t a single species that will better benefit your watershed. Although they can present a challenge, by using flow devices you can control problematic flooding and reap countless environmental rewards.

This article was originally shared on TheBeaversInstitute.org

 

How to Live and Let Live in the Land of Beaver

A Tale of Two Keystone Species

By Timothy Sexauer

Photo By Hannah Apricot Eckberg

 

For many millions of years, in what we now call the Applegate watershed of southern Oregon, beaver have been the senior landscape engineers. At least 12,000 years ago, humans arrived and established permanent culture alongside the beaver. In the language of the Takelma, the Applegate is called “sbink,” meaning Beaver Place.

By the time the Takelma were violently displaced by the gold rush settlers, fur trappers had already nearly exterminated the beaver. As a result, rivers and creeks flowed faster and wetlands had become meadows, drastically changing the landscape and ecosystems.

The settlers brought cattle and grain seed, turning this ancient fertility into pastures and hayfields, and introducing a different hydrological regime. Formerly ancient wetlands are now a mosaic of ranches, farms, and homesteads with culverts, concrete dams, and ditches designed to move water quickly to where it is wanted and then rapidly out to the sea.

However, today the beaver population is steadily on the rise, and they are still working with the ancient plan to slow water and create wetlands. Using their time-honored methods, they seek to fix any “leak” they discover in our fast-flowing hydrological system. The beaver’s efforts to reengineer human creations often leads to blocked culverts, flooded basements, or dead fruit trees. The most common outcome of these human-beaver conflicts is the human shooting the beaver, a detriment to reestablishing healthy beaver populations that would help replenish our withering waterways.

However, there are tricks to deal with such potential conflicts if we are willing to commit to a journey of observation, interaction, and working with nature – rather than against it. Hallmarks of any permanent culture.

 

A Keystone Quandary

Shortly before moving to a collectively purchased 80-acre property up a tributary of the Applegate River, I was thrilled to discover the creek on the property was home to beaver. I was rather dismayed that the previous owner had consistently torn out the beaver’s handiwork. To me, this was an opportunity to heal relations between two of the most influential keystone species on the property: humans and beaver.

However, not everyone shared my dreams of interspecies collaboration. Some of the landpartners were concerned about the dangers of wildlife, especially the tree-gnawing, landscape-modifying beaver. I saw this as a fascinating microcosm of the greater human-beaver clash, and that the lessons we would learn could also be useful for others.

It was recommended I talk to Jakob Shockey, director of the Applegate Partnership and Watershed Council’s riparian restoration program. As a wildlife biologist specializing in mammal behavior, he founded Beaver State Wildlife Solutions, a business that consults land managers dealing with wildlife conflicts, specializing in non-lethal ways of mitigating unwanted effects of beaver activity.

Shockey learned these techniques while working with his mentor, Mike Callahan. As a proponent of beaver science, over the last 20 years Callahan has mitigated over 1,400 human-beaver conflicts with the use of innovative flow devices. Pulling from his mentor’s knowledge and several years of his own experience mitigating beaver issues, Shockey has created a toolbox of techniques to deal with potential human-beaver conflicts-of-interest.

 

On the Level about Flooded Basements

Shortly after getting to know Jakob Shockey, he invited me to help with a pond leveler installation. A pond leveler is a flow device designed to keep a pond at a certain level when beaver damming activity would otherwise raise the water level too high for human preference.

The landowner is a lovely, elderly woman in the Illinois Valley who owns a property with a well-established beaver wetland downstream. She considers the property a wildlife sanctuary, and is especially fond of the beaver residing on the land and is well-aware of the many ecosystem services they provide. The situation turned complicated when a beaver decided to move upstream and dam the pond in front of her house, leading to a flooded basement. To allow the beaver to continue their work while ensuring that the pond stayed low enough to keep her basement dry, she hired Shockey to install a pond leveler.

Art By Mike Callahan, The Beaver Institute Inc.

A Flexible Pipe LevelerTM, as initially designed by Michel Leclair, consists of a length of 10”-15” flexible pipe extending from a deep spot in the pond to the downside of the beaver dam. The intake is secured in a cage with about a 6’ diameter, wide enough so that the curious and innovative beaver will not sense the flow of water into the pipe and attempt to “fix” the situation. The cage can be made with hog panels and hog rings to hold the panels in place. The outlet will pass through the dam at the desired height for the pond. Try to disguise the pipe with mud and sticks, and the beaver should build the dam back up around it. This will keep the water level constant and the beavers satisfied.

Protecting Culverts with Trapezoidal Fences

Another common beaver conflict is the damming of culverts and spillways, which to them look and sound like dam breaches that need fixing. Trapezoidal fencing is a flow device designed to address this issue. Skip Lisle invented it and called it a Beaver Deceiver.

Art By Mike Callahan, The Beaver Institute Inc.

The beaver will begin to dam against the fence near the culvert. As it continues damming, the fence discourages the beaver by forcing it away from the culvert. Also, the width of the fence increases, moving up from the culvert, which reduces the audible flow of water through the fence. Since the sound or feel of running water is the beaver’s cue to dam, they tend to stop damning when the water is quiet and not moving. Debris buildup should occasionally be removed from along the fence to avoid prompting the beaver to build a dam on top of it.

Combining the Fence and Pipe 

Another flow device innovation is the fence and pipe, a hybrid of the trapezoidal fence and the pond leveler, combining the benefits of both methods.

The fence keeps the culvert clear, while the pond leveler feeding through the fence ensures that flow continues at the desired level into the culvert, even if the beaver dams up the whole fence. This also eliminates the need for occasional debris removal along the fence, keeping humans and beavers happy.

Art By Mike Callahan, The Beaver Institute Inc.

Protecting Beloved Trees

While the end result of the beaver’s handiwork provides immense ecological benefits by creating wetlands that support many other species, trees do get felled as part of their handiwork. Beaver eat the cambium layer of the bark and use the branches and trunks for building material. While many of their favorite trees, like aspen, willow and cottonwood, co-evolved with beaver’s coppice practice and actually benefit from it, beaver also tend to fell other trees that do not regenerate, such as prized heirloom fruit trees of riparian homesteaders. Today, this is the most frequent reason that beaver are killed.

To protect a large area of trees, such as an orchard, an electric fence is an effective beaver deterrent. The wire should be placed 4” off the ground. If there is a lot of organic matter on the ground, Shockey suggests running a ground wire along with your hot wire. Beavers will quickly learn to avoid the fence and the trees will be safe.

To protect individual trees, Shockey finds the most effective method is to paint the trunk of trees with a mix of half sand and half latex paint. The beaver’s teeth are it’s prize possession and most important tool for survival. As soon as it feels the sand grinding it’s teeth, it will immediately stop gnawing.

Paint a few feet above ground level, taking into account the potential snow level in winter. Use non-synthetic latex paint without mercury. You can color match the paint to your tree’s bark color, although some orchardists paint their trees with white latex paint which is said to increase sap flow in the spring.

Finally, it is useful to plant willow cuttings along the waterway. If the beaver has plenty of its preferred food they are less likely to seek exotic fare. To easily plant willow, harvest cuttings in the winter when it is dormant, and push branches 2/3 of the way into the soft soil near the water’s edge. Willow contains a potent root-forming enzyme, and should take easily.

 

Photo by Cheryl Reynolds/ Worth A Dam

Bringing it Home…

Jakob Shockey says the key is mitigating human-beaver conflicts so we can retain beaver where they choose to reside. When they are secure in their chosen spot they will naturally disperse their children further up tributaries where we most need to restore water retention. It is up to us to educate ourselves and others about the many benefits of beaver to the land and, importantly, the ways that we can non-lethally deal with these conflicts.

It is an honor to announce that Mike Callahan recently launched The Beaver InstituteTM as a means to catalyze public awareness at a continent-wide scale. The Institute’s mission is “to be a catalyst for advancing beaver management by providing technical and financial assistance to public and private landowners experiencing beaver conflicts, supporting scientific research, training mitigation professionals, and increasing public appreciation of the beaver’s critical role in creating wetland ecosystems.” The vision is to have “all beaver-human conflicts resolved in a science-based manner to maximize the many benefits that beavers contribute to the environment.”

BeaverInstitute.org hosts a great deal of information about the ecology of beaver and how to benefit from it. There is also a free extensive online database of PDFs and instructional videos about various conflict mitigation techniques and devices. We have the tools we need become a culture of citizen-scientists and help our toothy, furry friends resume their important role in the hydrology and ecology of North America.

For help with wildlife conflict on your land in Oregon, Jakob Shockey can be reached through his website, BeaverStateWildlifeSolutions.com.  

 

Here is the original article, as seen in Issue 08.

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