Raging wildfires have left visible scars on much of Manitoba’s landscape this season, but the impacts of the fires can go much deeper, including right to the bottom of the lake.
Researchers say this year’s record-setting wildfire season could be taking a toll on aquatic ecosystems.
“The loss of habitat — the trees and the brush around the lake systems — that introduces more light and that can cause a whole host of problems where we potentially have algal blooms,” said Alexandra Schoen, a researcher and fish culture programs manager for the Province of Manitoba.
“UV light can disrupt fish egg development.”
Schoen says the wildfires can create a range of other risks to fish and aquatic ecosystems, including disrupting the food web, changing the water’s temperature and chemistry, and the loss of trees and vegetation on land can create increased runoff into bodies of water.
“That could be as simple and silt and dirt that’s flooded into the lakes or it could be more toxic — so, chemicals from the fire retardants that are being sprayed up north and all over the province,” Schoen explained.
“Those can have a whole host of problems — both physically, like clogging fish gills, potentially, but it can also have indirect effects like physiologial effects, like changing fish behaviour or changing how they feed or reproduce.”
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Terri-Lee Reid, a freshwater conservation researcher with the Canadian Wildlife Federation, says wildfires can also have some environmental benefits, including allowing for regrowth of vegetation and regeneration of nutrients in soil. Certain trees, she says, like the jackpine and lodgepole pine, require heat from fires to open their cones and release seeds.
“Depending on the number of wildfires, the intensity of the wildfires, the location of the wildfire, how healthy the ecosystem was before the fire and how much rain falls after the fire, wildfires can also have harmful impacts to our freshwater,” Reid said.
Reid also says the longer and more intense wildfire seasons could mean longer-lasting impacts on aquatic ecosystems.
“We are seeing more fires and more intense fires and that can certainly have an impact on our freshwater,” she said.
“Especially if the fires are occurring near fresh waterbodies, or if the same areas keep being impacted by fires, because then they will have little time to recover in between.”
Schoen, who also conducts research at the Whiteshell Fish Hatchery, says the wildfire season has also prevented fisheries from stocking certain lakes in northern Manitoba. She says the true impact won’t be known until they are able to get into the wildfire zones, and some of the impacts could go far beyond this wildfire season.
“There can be these really prolonged effects,” Schoen said. “Sometimes you’re dealing with changes that last for days, and sometimes with pH or water chemistry, you’re dealing with changes that last years.”
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