Researching peatlands for restoration

Letting water back in and fertilizing the soil may help get peat plots back on track.

© DUC

A faint buzz reverberates over open plots of harvested peat above a team of researchers in southeastern Manitoba. At first the sound could be confused with one of the province’s legendary mosquitoes hovering near the ear. But this mechanical pitch comes from a drone far overhead.

Pete Whittington, a hydrogeologist from Brandon University, stands on the ground with a remote control, taking photos using the aerial drone. Whittington and a group of fellow researchers from across the country are planning research in the area and the drone will allow the team to see the layout from above.

Stretching a few hundred metres out from the road are rectangular peat plots, peppered with chunks of decomposing wood and hemmed in by the dense vegetation of the boreal forest. From his bird’s eye view, a few bright green plots stick out where vegetation has been re-established by rewetting the site.

Neighbouring the plots are bogs and fens full of mosses, shrubs, sedge grasses and stunted trees. Underneath the dense vegetation are deep peat deposits that are full of water. So much you can wring it out of the spongy sphagnum moss.

When these plants die they are unable to fully decompose in the saturated ground. Over thousands of years, this slow accumulation of partially decomposed mosses forms peat – a carbon-rich soil found at every garden centre in the country.

But to harvest the peat, producers must drain these wetlands, and when they’ve harvested all the good stuff, dry, open plots remain. Exposed to oxygen, the remaining ancient plant matter finally breaks down. All around Whittington, the spent peat harvest sites are releasing a slow, invisible seep of carbon.

Though the carbon is invisible, the greenhouse effect is not. It’s been a hot, dry spring in Manitoba and climate change is on everyone’s lips. It’s why the scientists are here. They want to figure out how to help get this ecosystem back to work for the climate, so it can take carbon out of the atmosphere and bury it underground once more.

“We’re looking for ways to set these peat bogs back to a more natural state,” says Pascal Badiou with DUC’s Institute for Wetlands and Waterfowl Research. “We want to find a way to bring back the vegetation at these sites so they start storing that carbon again.”

Images from the drone show the researchers have a head start. Operations staff say when they built dams to direct water back into the bog, they built one in the wrong place. One retired field didn’t get rewetted, and it is noticeably less green than the others.

“That’s perfect!” says an excited Line Rochefort, a peatland expert from Université Laval’s Peatland Ecosystem Research Group. “Without knowing it, you’ve been running an experiment for us for nine years.”

The researchers will study how letting water back in and fertilizing the soil may help get the peat plots back on track. They’ll see how this might help peat producers rehabilitate their expired plots. DUC will evaluate the effects of this rewetting and fertilization on downstream streams and lakes. It’s part of a partnership with the Canadian Sphagnum Peat Moss Association to support conservation and sustainable practices for peat harvesting and restoration.

“Vast swathes of the boreal forest are peatlands,” says Badiou. “Their health and the health of the planet go hand-in-hand.”