Are Beavers Untapped Talent in Restoring the Severn?

by Joan Treichel, SRA science reporter

The North American beaver has been promoted from “top hat” to “eco-engineer.”

So reported Scott McGill. a stream and wetland restoration expert, during a talk sponsored by the Maryland Stream Restoration Association this winter. 

Many aspects of the beaver’s capabilities were also reviewed by McGill’s colleague, Rachel Ortt, Eco-credits Market Coordinator with Ecotone, Inc. during SRA’s recent John Wright Speaker Series presentations.  
         
The beaver was almost driven to extinction during the 19th Century, McGill explained, because of the demand to turn the beaver’s fur into men’s waterproof top hats, among other clothing.

McGill, in contrast, is deploying beavers to help restore streams and wetlands.

He’s using them because they are “ecosystem engineers” and they’ve helped restore 40 miles of streams and 1,400 acres of wetlands in the mid-Atlantic region, the Chesapeake Bay and its tributaries, as well as in some other areas of the United States.
               
How do beavers assist stream and wetland restoration? “Via the dams they build,” McGill said. Here’s how it works.

Beavers build dams to create ponds. They then build lodges in those ponds where they live and raise their youngsters.

These ponds also have some other salutary effects: they connect water in the ponds with nearby plants. The water-plant interactions in turn create wetlands, and the wetlands then provide “amazing habitats” not just for the beavers, but for fish, ducks, and other kinds of wildlife.

Moreover, getting beavers to build their dams in desired areas is “almost free,” McGill pointed out.

This means planting some of the trees they like to eat. The trees might be, for instance, willow, dogwood, red maple, box elder, or river birch.

This also means putting some woody material into the area of interest that they can use to build their dams.

You can put the material in place by hand if you don’t have any equipment to help you. “If you set the table and give them what they need, they will show up eventually.

Now granted, beaver dams can block water flow and create flooding, McGill conceded.

But there is a way to deal with the problem: place a water-flow device in the dam that brings the water level down a little, but not enough to disturb the beavers’ existence.

For example, he and his colleagues have placed some water-flow devices in beaver dams located in the Severn River or in streams feeding into the river, McGill noted.

Can beavers be enticed to build dams in areas populated by people? “Absolutely!” McGill said.

There is a beaver colony in White Marsh, Maryland, near urban development. “Beavers don’t know they are in an urban environment. They just want to feel at home and raise their kids. If you are fortunate enough to have a beaver family living near you, go out at dusk, and you may well see them feeding, McGill advised.  

Beaver have also been busy throughout the Severn River watershed. They’re active in the freshwater streams feeding our many creeks, from Lake Ogleton, to Clements, Brewer and Chase Creeks and up into the Severn Run Environmental Area at the top of the river. 

McGill and his colleagues aren’t the only people using beavers to restore streams and wetlands. He attended a beaver conference in Utah in 2017, where some 100 people from various countries reported on their experiences in this domain, he said.

Scott McGill is the founder and CEO of Ecotone, Inc., located in Forest Hill, Maryland. Ecotone started as a two-person consulting firm in 2000. Today it has 80 employees.  

McGill’s email address is smcgill@ecotoneinc.com.