Revegetating the Dillon Creek wetlands

Roy L Hales/ Cortes Currents - In the conclusion of a 3 part series about the Dillon Creek wetlands restoration, Project Manager Maranda Cross talks about BC’s disappearing wetlands and the revegetation currently underway at Linnaea farm on Cortes Island.

“Forestry, agriculture and residential developments are our main threats to ecosystems on Cortes Island,” said Cross. “Many residential homes are built in wet places so they drain the landscape. It's such a common practice that I don't even know that people recognize it as draining wetlands, but every time a ditch is dug that moves water, a wetland is being drained or a stream is being straightened. The impacts of that are great, especially in densely populated areas.”

Cross said that the Lower Mainland has lost 90% of its wetlands and the range is 60 to 90% throughout southern British Columbia.

“On Cortes we're not as densely populated we still have some remaining intact wetlands around. So we're probably closer to 60%,” she said. “Everywhere I walk on Cortes Island, I see ditches and drained wetlands.”

The iconic western red cedar is among the species now forced to cope with a lowered elevation of groundwater in its habitat.

“That's why restored wetlands can be so crucial for this species,” said Cross. “We are bringing the groundwater levels back up, rehydrating and resaturating the soil.”

Last August, two of the pastures at Linnaea Farm were decompacted and the soil artificially shaped in the the high spots and low spots that exist in nature. The revegetation started shortly after that.

“We had some early rains in September, so we planted just about 300 native plants. I think 30 different species as well as a native seed mix that we collected locally from wetlands,” she said.

One of the species they are planting in the Dillon Creek wetlands is cottonwood. The early settlers thought of cottonwood as a weed, but recent studies found that it sequesters carbon at a greater rate than other species, because of its rapid growth in the first 20 years. Beaver love this tree’s high protein content and actually grow larger when eating cottonwood.

“I love cotton wood because it's also a medicinal plant. The resin in the cottonwood buds is usually collected after a big storm in March. In some places it's called Balm of Gilead,” said Cross. “It has propolis in it and it smells like this kind of sweet, aromatic smell. I make a salve out of that's very high in vitamin E, and antimicrobial and antifungal.

She knows of four or five cottonwood trees on Cortes. They are a wind pollinated species, but are spaced too far apart to pollinate each other.

One of them is where Cross once lived, on the hillside across the street from Linnaea farm. Ken Hanson lived there after he sold Linnea farm in 1978. There was a beautiful orchard, a garden and an old cottonwood tree on the south facing slope.

“The other place there's an old cottonwood tree is right at the north end of Cortes Bay. Those trees just aren't close enough to pollinate each other, so we've planted cottonwoods now at Linnea in the hopes that we'll be able to reestablish a population of cottonwoods that will naturally revegetate the area,” said Cross.

They also planted three different species of willows, a riparian species that will help stabilize the soil around the wetland.

“Our end goal is to leave vegetate the areas that we've disturbed because we have disturbed the soil. It was a vegetated field and then we brought in excavators and we dug it all up,” said Cross. “We exposed all this soil. If we don't put native species in there and use mulch and invasive species management, then that area will become overrun with invasive species like blackberry, holly and possibly Broom.”