Wednesday, April 21, 2010

Ecologically speaking, beavers don't totally suck.

As it turns out, beavers are actually good for something besides hats no one wears anymore, or knocking over on your way to the Rose Bowl. Below is a nice story from the North Coast Land Conservancy Stewardship Director, Celeste Coulter, about how beavers can lend a hand and their big buck teeth in improving native habitat. Huzzah, beavers!

Are You a Beaver Believer?
by Celeste Coulter, Stewardship Director

February 8, 2010, 11 a.m.:
Running late, I turn off Lewis and Clark Road and park next to our property called Thompson Falls (80 acres), located on the northeast side of Seaside. I’m meeting NCLC board member Doug Ray of Carex Consulting and Alan Moore from Trout Unlimited.

A cacophony of sound surrounds me as I step out of the car. It could only be one thing: the Pacific chorus frogs are breeding. Although one of the smallest frogs in Oregon, the Pacific chorus frog (Pseudacris regilla) has one of the loudest calls. Male chorus frogs call throughout the lengthening daylight hours during warm rain showers when breeding is taking place and females are laying eggs. The calls are produced by a dark gray inflatable throat patch that develops on males during the breeding season, allowing them to serenade their female companions with loud “ribbets” and seductive, high-pitched trills. Studies have found that one male frog will act as a chorus master by leading the others males to begin calling. My attention is fixed on this seasonal symphony when Doug drives up in his truck. As usual, he greets me with a big smile, brimming with excitement over the project we are about to discuss.

Before Seaside became a coastal settlement, Thompson Creek used to flow down through the canyons of the Coast Range, meandering out into the flat, coastal terrace of the estuary. Today the floodplain is filled with reed canary grass (an invasive introduced species) and resembles a vacant lot. We’re hoping to change that, which is the reason for our meeting. Alan soon catches up with us and we begin wading through the grass toward beaver territory. Beavers discovered Thompson Creek in 2005. One of the largest beaver dams in the area is on a creek just south of here measuring over 100 feet in length. Because of these dams, native plants are beginning to thrive and non-native plants are decreasing in abundance. The Thompson Falls property is unique in that it is dissected by a housing development. The unusual property boundaries were determined to maintain the site’s ecological integrity—in other words, to make sure that the existing streams, tributaries, swales, and ponds are all connected to each other.

Alan walks a few paces behind Doug and me while we chatter back and forth. Our enthusiasm soon infects Alan as we share the information we learned at a recent conference on beaver ecology. Research has repeatedly shown that beavers are able to restore wetlands and juvenile fish habitat in a way that far exceeds any human-engineered project—and at a fraction of the cost. The project currently under way at Thompson Falls is a beaver habitat enhancement project. We had planned to install startup dams made out of logs and stumps to entice beavers to colonize the lower meadow and thereby restore the Thompson Creek floodplain, but to our surprise, the beavers beat us to it. We reach the southern boundary of the property where a large drainage ditch has been dug to divert water from the pasture (floodplain). Standing on the edge of the ditch, we view signs of beaver activity: carefully stripped stems of blackberry and Scotch broom, fallen red alder saplings, and, of course, beaver dams. At Thompson Falls, beavers use what is available, and because blackberry is the most common woody shrub, beavers are making good use of its canes. The dams are packed with mud, blackberry, Scotch broom, and what little red alder and willow the beavers can find.

Our excitement grows as we find two more dams. Doug and I discuss the possibilities. With the current beaver activity, the wood placement is sure to succeed. But it doesn’t take long for all of us to be sobered by the abundance of non-native plants at the project site. Unless there is enough food for the beavers to eat, they won’t stick around and reproduce, which means they won’t restore the floodplain back to a wetland meadow. To make this project work, we’ll need to plant a lot of willow—in fact, thousands of willows if we’re going to keep a colony of beavers happy. That’s where Alan can help. Unless we can protect the plants until they can become well established, the beavers will wipe out the entire planting effort. Trout Unlimited adopted Thompson Creek as a project site a few years ago when they discovered that one of the largest runs of coho salmon along the North Coast spawn in the upper reaches of the creek every year. Since then, our partnership with Trout Unlimited has brought volunteers from the Tualatin Chapter out to the coast to remove blackberry and Scotch broom and to plant native plants. Without their support, much of the work that has been accomplished at Thompson Creek would not have been possible.

A herd of elk, flushed out of a nearby dune ridge, suddenly interrupts our conversation. At least 40 large animals stampede by us to get to safe ground. Our habitat development plans will not only help beavers and coho, but other wildlife such as elk will thrive in the native shrub-scrub habitat and in the open meadow habitats we hope to establish. The sudden rush of elk stills our movement as the afternoon sunlight warms our backs and chorus frogs sing in the distance. Thompson Falls is only going to get better; signs of beavers have sealed our fortitude. We are beaver believers. Our conversation turns to the future of this floodplain, where native plant communities intertwine with slow winding channels intercepted by beaver lodges and willow thickets, providing a place where people and wildlife alike can thrive.