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Appreciate our furry ecosystem engineers

The DC area's beaver population has boomed in the past 20 years, and that's a great thing.

Beaver at Kenilworth Aquatic Gardens. Photo by Glyn Lowe Photoworks on Flickr.

It's a sign that our region's waterways, having suffered from decades of channelization, pollution, neglect and mismanagement, are starting to regain their ecological health, though much work remains to be done.

The industrious creatures' presence brings challenges when their work conflicts with human activity, but beavers, which biologists recognize as a keystone species, benefit the environment far more than many people realize.

There are many tools for coexisting with beavers and the other creatures their ponds attract, even in highly developed areas. The alternatives to coexistence tend to be inhumane, ineffectual and shortsighted.

The beaver, North America's largest native semiaquatic rodent, is often misunderstood and greatly under-appreciated. Yes, they do cut down trees and build dams that can flood parts of low-lying areas. But these activities bring a host of benefits for ecosystem health, biodiversity, other wildlife, and for water quality, erosion abatement, flood control, and even act as carbon sinks that take greenhouse gases out of the atmosphere.

Beavers abounded throughout North America prior to Europeans' arrival, and they were almost certainly abundant in our region, which boasted a great deal of marshland and a plethora of streams, some of which humans have built over or removed by human activity.

Beavers were hunted and trapped nearly to extinction by the turn of the 20th century, mainly for their fur. But one of the greatest success stories of the modern wildlife conservation ethic has seen the industrious rodents return to almost all of their historic range.

At the same time, efforts to allow native vegetation to grow along stream beds in urban and suburban areas to improve water quality has recreated attractive habitat for beavers. They have come to inhabit creeks and streams in urban and suburban areas across the US, where their activity has at times come into conflict with human desires.

Sign at Lake Artemesia in College Park. Photos by the author.

Nature's engineers now inhabit a number of waterways in our region, including Rock Creek, the Anacostia River and its tributaries (including Kenilworth Aquatic Gardens), Lake Artemesia in College Park, Roaches Run Pond in Arlington, and Lake Accotink in Springfield, just to name a few.

Stories of trouble stemming from beavers' handiwork have appeared with regularity in the Washington-area press in the past two decades. In some cases, such as when beavers felled some of the beloved cherry trees along the Tidal Basin in 1999, trapping and removal of the beavers is unavoidable (luckily, this particular colony was able to be relocated to a more favorable site in the area). But in others, humans have harassed or killed beavers and destroyed their dams for no good reason.

One such incident occurred in Hyattsville's Magruder Park (located, aptly enough, on Beaver Dam Park Road) in the spring of 2011. One or more beavers dammed up the small stream draining into the Northwest Branch of the Anacostia on the park's west end, creating a small pond, which also covered a small portion of the adjacent parking lot. This did not seem to present a significant inconvenience to park visitors, and park managers cut a hole in the dam in attempt to let some water drain while retaining the beavers. But sadly, the dam was found broken up one morning in April along with the carcass of its architect.

This beaver-created pond still stands at Magruder Park in Hyattsville. Photo by the author.

The trouble with exterminating beavers is that, as long as the habitat in question remains reasonably healthy, other beavers are likely to come to the same spot. Each year, beaver parents evict their one or two-year-old offspring from their lodge and they go in search of new homes. And no matter how many times humans destroy a beaver dam, beavers will keep rebuilding it.

So in places like Magruder Park, unless park managers were to remove all the vegetation around the stream and keep the area clear—which would be undesirable—to keep removing beavers each time they show up is to fight a losing, and ecologically foolish, battle.

It is far better for people to learn to coexist with their wild neighbors. In cases where flooding or high water levels are the issue, several devices exist to regulate water levels while leaving beaver dams intact and tricking beavers so that they do not seek to raise the water level.

Trees can be protected by wrapping their trunks in cylindrical cages, and a low fence will keep beavers away from a particular group of trees. Beavers tend to fell fast-growing tree species that have little commercial value, and this culling makes room for more, bushier growth the next spring, restoring a more diverse mix of flora to the wetland area over time. Beavers largely subsist on seaweed, clover, and land and aquatic plants other than trees.

Beaver ponds attract and sustain other wetland-dependent creaturessuch as turtles, herons, otters, ducks, and many types of birds and fish. They also do a good job of retaining stormwater runoff, allowing pollutants to settle out before the water moves downstream. Beavers have also become a unique cultural asset to cities and towns: they are local celebrities in places like the Bronx River in New York and Chicago's Lincoln Park.

But perhaps the best-known "downtown beaver" success story comes from Martinez, California, a Bay Area city that rehabilitated part of the creek that runs through the center of town. When a beaver colony established itself there in 2008, the local government threatened to have them removed. But citizens' organization Worth a Dam rose to the creatures' defense, and the city has come to celebrate its newfound furry, feathered and finned denizens, which have even attracted visitors from around the country and overseas (many of whom arrive on Amtrak).

The challenge of coming to terms with beavers in urban areas is a microcosm for the necessary large-scale work of reconciling human needs and desires with the natural systems that sustain all life. In our region, we can and should find ways to allow, and even help, beavers to do what they do best: maintain healthy wetlands. In return, we will enjoy cleaner water, better regulated stream flows, less severe flash floods, and the chance to interact with a wide array of wild creatures.

Malcolm Kenton lives in the DCís NoMa neighborhood. Hailing from Greensboro, NC and a graduate of Guilford College, he is a passionate advocate for world-class passenger rail and other forms of sustainable transportation and for incorporating nature and low-impact design into the urban fabric. The views he expresses on GGWash are his own. 


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Many folks think beavers are exotic creatures from far away lands and are therefore amazed to find out that they are fairly common in the Anacostia watershed - even in the heart of urban areas. It's great fun pointing out the beavers and the signs of their activity when I do river trips and other watershed tours.

by Brent Bolin on Mar 11, 2013 2:53 pm • linkreport

I once took a group of kids on a field trip to great falls and it took a lot of convincing to show that Beavers can live in Northern Virginia and that we could see the evidence by looking at a number of beaver-felled trees.

There is also the Ballston Beaver Pond which now boasts its own website/fan club.

by drumz on Mar 11, 2013 3:02 pm • linkreport

Yet another reason to avoid building man-made structures directly on flood plains. I look forward to the day when the Tidal Basin is a marsh more famous for its red fox than its Fanne Fox.

by Tom Veil on Mar 11, 2013 3:09 pm • linkreport

thanks, love this post.

by Tina on Mar 11, 2013 3:24 pm • linkreport

What is wrong with you people? This thing has been up for almost an hour!

Fine, I'll say it...

Nice beaver!

by Tim Krepp on Mar 11, 2013 3:37 pm • linkreport

Ballston Beaver Pond is a catchy name, but it was not created by beavers, unless VDOT engineers qualify as rodents. It's a detention pond for I-66. There are beavers there from time to time, but no permanent population.

by Paul on Mar 11, 2013 4:18 pm • linkreport

Kingman and Heritage Islands are a great spot for observing beavers and their handiwork. I've never seen one on land there but there's at least one substantial lodge on Heritage Island and they swim in Kingman Lake all the time.

by jimble on Mar 11, 2013 4:47 pm • linkreport

"The beaver, North America's largest native semiaquatic rodent..."

Could simplify this to: "the beaver, North America's largest rodent..."

by Sam on Mar 11, 2013 5:11 pm • linkreport

Rabid beaver attacks 83-year-old woman in Fairfax County lake

An 83-year-old woman was hospitalized with numerous bite wounds after being attacked by a rabid beaver while swimming in Lake Barcroft near Bailey's Crossroads.

An onlooker repeatedly struck the 35-pound animal with a tree branch and then threw a fish net over it. Fairfax County Animal Control officers arrived on the scene and euthanized the animal.

The beaver tested positive for the rabies virus, officials said.

Lake Barcroft resident Mike Korin was fishing at the time Lillian Peterson was attacked.

"I saw the beaver acting abnormally; there were lots of splashes," Korin said. "About 10 minutes later, I heard a swimmer screaming for help. I boated over to her, administered first aid and called 911."

The attack, which occurred about 6 p.m. Tuesday, is the second in Virginia since mid-July, when two sisters swimming in Lake Anna in Spotsylvania County were bitten by a 65-pound beaver. That animal was reportedly shot with a BB gun before being transferred to a lab in Richmond, where it was found to be rabid.

A similar attacked also occurred last month in New York, where a Boy Scout leader was bitten in the chest by a rabid beaver while hanging onto a noodle float in the Delaware River. Once the man reached shore -- beaver in tow -- the Scouts used rocks to kill it.

Despite the spate of attacks, the head of a nonprofit organization dedicated to helping people learn about beavers said beaver attacks are extremely rare.

Sharon Brown, biologist and director of Beavers: Wetlands & Wildlife, has raised and aided beavers for more than 20 years. She said Wednesday that beavers are peaceful vegetarians who coexist with hordes of other animals living in their habitat and almost never attack humans.

"Beaver attacks are not on the rise," she said. "It's just not something beavers usually do. Occasionally, if a beaver feels cornered and is fearing for its life, it may attack -- but even that is rare."

Lee Walker, outreach director for the Virginia Department of Game and Inland Fisheries, said beavers are common throughout the state. Although the organization keeps no official record of beaver attacks, he said they are "pretty rare."

Fairfax County police spokeswoman Lucy Caldwell said the Lake Barcroft attack was the first in Fairfax County since at least 2000.

Caldwell said the victim was being treated with rabies-preventative medicine, and Korin said Peterson was in "high spirits" when he saw her Wednesday.

Sally Determan, president of the Lake Barcroft Association, said she has recommended that people not swim in the private lake for the time being.

"We want to consult with experts and see what, if anything, we should do," she said.

Each year, about 450 animals are submitted from within Fairfax County to be tested for rabies, and about 40 to 60 of these animals test positive, according to officials with the Fairfax County Health Department.

by Naomi Jagoda on Mar 11, 2013 5:15 pm • linkreport

Killed by a rabid beaver, eh? I can see this coming up on Leno.

by Chris S. on Mar 11, 2013 6:01 pm • linkreport

I see beavers pretty regularly along the Anacostia Riverwalk Trail. I saw one not too long ago that wouldn't move off the trail. He was so unconcerned about me that I think I could have sat next to him and put my arm around him without him even stopping what he was doing (eating grass or something). Of course, I didn't. I just diverted into the road and then back onto the trail

by David C on Mar 11, 2013 6:43 pm • linkreport

You mean to tell me that, on occasion, wild animals can be dangerous? Why I never! Clearly, we should exterminate all wildlife to protect ourselves...

by Ms. D on Mar 11, 2013 9:01 pm • linkreport

Thanks for the tip on the Ballston Beaver Pond. I wonder why the Arlington County government moved to exterminate the beavers? I doubt their activity at that particular location was threatening to flood any buildings or roadways. I'm guessing lack of enough wood to eat in that very constricted space led the beavers to leave.

Regarding the rabid beaver attack: rabies can affect a number of animals and cause them to behave in ways they wouldn't otherwise. A healthy beaver will never attack a human unless he feels his life is in danger. A beaver's preferred response to danger is always to flee and dive into the water. And Ms. D is right that there are far better ways to control the spread of rabies than killing off wildlife.

by Malcolm Kenton on Mar 11, 2013 10:06 pm • linkreport

VDOT didn't build the pond for the beavers but the beavers were able to move in and create a habitat worth caring about anyway.

Also my advice for avoiding animal attacks would probably include choosing to swim at one of Northern Virginias many municipal pools.

by Drumz on Mar 11, 2013 10:11 pm • linkreport

It is nice to have the beavers, but jury is out on the value of wetlands as a carbon sink. Wetland make a lot a methane.

by goldfish on Mar 11, 2013 10:27 pm • linkreport

What a great post! Yes the cities who learn to coexist with beaver reap a HUGE reward. Now because of our beaver-created wetlands we regularly see otter, steelhead, woodduck and even mink in our tiny urban stream.

Any city smarter than a beaver can keep a beaver - and knows WHY they should!

by Heidi Perryman on Mar 11, 2013 11:27 pm • linkreport

Was the beaver that viciously attacked the woman at Lake Barcroft last year also a friend of the fawners here? Since when do we need our trees felled and lands flooded? These “engineers” put the V in varmint.

by AndrewJ on Mar 12, 2013 8:00 am • linkreport

What a lovely article. Beavers are such beautiful creatures. I am glad they are back. We should be glad and grateful they are are neighbors.

by Michelle on Mar 12, 2013 8:05 am • linkreport

Was the beaver that viciously attacked the woman at Lake Barcroft last year also a friend of the fawners here? Since when do we need our trees felled and lands flooded? These “engineers” put the V in varmint.

But I thought people moved to the suburbs for the presence of bucolic natural landscapes!

by MLD on Mar 12, 2013 8:32 am • linkreport

Sure,. but you have to dig under a mixed use development to find one these days.

by Chris S. on Mar 12, 2013 9:39 am • linkreport

I would again, advise anyone looking to prevent a beaver attack on themselves to not swim in lakes or ponds. I've avoided being bitten by a beaver my whole life by doing just that.

by drumz on Mar 12, 2013 9:39 am • linkreport

Why wouldn't you swim in a nice lake or pond?

by Chris S. on Mar 12, 2013 9:52 am • linkreport

Do it, I don't care. Just don't use it as evidence that there is some rabid beaver epidemic in Fairfax county which has something like 20+ recreation centers all with pools.

by drumz on Mar 12, 2013 9:58 am • linkreport

Pools are fine but hardly a replacement for lakes. Just like an exercise bike is a poor replacement for cycling on a trail.

by Chris S. on Mar 12, 2013 10:12 am • linkreport

i would hope any issues at Lake Barcroft can be addressed without exterminating all beavers in the region.

by AWalkerInTheCity on Mar 12, 2013 10:26 am • linkreport

Any animal (including a human) with rabies is bad news. This excellent graphic from the Washington post put the risk of rabid beavers in perspective.

by Heidi Perryman on Mar 12, 2013 10:40 am • linkreport

"Any city smarter than a beaver can keep a beaver"....perfect! So get your thinking caps on folks, not your killing caps. Use that supposedly superior brain for constructive applications and not destructive. Killing anything inconvenient is easy, but lazy. Beaver are a keystone species and worthy of respect.

by JT on Mar 12, 2013 11:05 am • linkreport

Thanks for the graphic. I'm an animal lover but if we need to cull some population to prevent rabies, I'm not going to shed any tears over raccoons. They freak me out.

by Alan B. on Mar 12, 2013 11:37 am • linkreport

perhaps the bright and shining day will dawn when humans
will awaken to the undeniable truth that we share this world
with myriad other sentient beings who fully deserve, at the very least,
our respectful consideration of their absolute right to exist.

by glen smith on Mar 12, 2013 9:45 pm • linkreport

Love the article. In a time when both drought and flooding are problems and the water table is often subsiding, the work of beavers can be very beneficial indeed. Thanks for a voice moving us in the direction of sanity. And a nice writing style to boot.

by Frances Griffin on Mar 13, 2013 4:07 am • linkreport

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