Researchers studying recovery of Waterton plant life post-2017 Kenow wildfire

During the second and third growing seasons following the fire, McCune and her students observed both burned and non-burned plots of land that were originally surveyed in the mid-1990s to compare the plant species present.

The team wanted to find out how plant life is impacted by stressors like wildfires and increased human presence.

Since the initial surveys were completed, park visitation has gone from about 300,000 people per year to over 500,000 per year. Officials say the impact of more visitors in the park is mainly seen on the trails in Waterton, potentially increasing the spread of seeds on boots and clothing.

“Our study was trying to test the way that these plants are responding to the fire — is it different if they’re closer to a trail than if they’re far from a trail?” McCune asked.

The university notes that all the burned plots had large shifts in the composition of plants, regardless of how close they were to a trail.

“Mostly this was because of all the species that were lost during the fire,” McCune said.

“Lots of species that were in those plots in the 1990s were wiped out when the fire came through. We thought the shifts in the plant composition might be greater closer to trails, but that wasn’t the case,” he added.

“But then in the plots that didn’t burn, what’s interesting was they had greater shifts farther from trails, which is the opposite of what we expected.”

Researchers believe the shifts in plant life could be due to increasing tree density in the forest and forest encroaching on grasslands.

Additionally, the expanding canopy cover provides an environment for shade-tolerant plants and more woody plants to grow, which in turn causes them to increase in the non-burned areas.

“It was almost more fascinating to look at what happened in the plots that didn’t burn,” McCune remarks, adding, “We know what happened in the burn. Pretty much all the trees were killed. Almost everything was severely burned.”

“Afterwards, the fire followers come in like fireweed and dragonhead. We mostly found what we were expecting in the burned plots.”

Exotic plants

Officials say the spread of exotic plants is a concern for the park. These are species that are not native to the area, and some are invasive. Researchers anticipated seeing more exotic plants in burned plots that were closer to a trail.

However, McCune said they did not see that.

“We did see that plant species that are associated with disturbance, which can be native or exotic, increased significantly in the burned plots and increased even more if the burned plot was close to a trail,” she notes, adding that plant recovery needs to be tracked over the long-term.

“In the plots that burned, on average, about 40 per cent of the plant species that were there in 1995 were still there after the fire. I found that pretty astonishing given how severe the fire was. It really speaks to the resilience of these communities.”

This summer, McCune and her students will return to the same plots. This will mark the seventh growing season since the 2017 wildfire.

Researchers will track whether the communities go back to the same composition and the same species as before the blaze or if they go in a different trajectory.

“This is a great partnership we have with Parks Canada and the main botanist who did some of the surveys in the 1990s, Dr. Peter Achuff, is still around and working with us,” says McCune.

She hopes they can continue to follow the plots over many years. Some of the findings have been published in the journal Landscape Ecology.

by Justin Goulet

Researchers studying recovery of Waterton plant life post-2017 Kenow wildfire

Exotic plants

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