Dr. Katherine Stewart (PhD) didn’t set out to fall in love with Canada’s North but it happened anyway.
An assistant professor in the College of Agriculture and Bioresources, Department of Soil Science, at the University of Saskatchewan (USask), Stewart got her first taste of the Arctic while doing her doctoral work at the University of Northern British Columbia.
“I did some work north of Yellowknife in the low tundra area, then ended up going to the high Arctic,” she said. “I just got the Arctic bug!”
There is something about the North that draws people—the vastness, the beauty, the fragility and the power of the place all have a pull. For Stewart, it’s that and more—the deceptively complex plant and soil ecology, the need to better understand that ecology and restore it in ways that make sense not just for the planet, but for the people who live there.
Extractive industries operate right across Canada and most employ land restoration techniques once the mine or rig leaves. In southern regions where plant diversity is much greater and the growing season much longer than in the North, how to do this effectively is well understood. Not so for the Arctic.
“We’re still really just starting to understand tundra systems,” said Stewart, adding that effective ecological restoration protocols are still being worked out. Plant and seed propagation, for instance, isn’t as practical for a region governed by permafrost and a short growing season.
“It’s very hard to break dormancy,” she said. “A plant could be in a greenhouse for two years, making it a very expensive plant.”
So what can we do to reclaim and restore mine sites in Canada’s North? That’s what Stewart and her team is starting to find out.
The restorative power of biological soil crusts
One avenue for restoration that Stewart is investigating is biological soil crusts (BSCs). These are the lichens, bacteria, fungi and other organisms that live on the surface layer of tundra. BSCs are important for carbon and nitrogen cycling as well as soil stabilization, and it should be noted that while they form in the spaces between vascular plants, they are not comprised of these plants.
“I’m really interested in how soil crust communities assemble,” said Stewart.
She got a good chance to see this in action in 2018, when Canadian mining company Agnico Eagle Mining Ltd asked her to do some restoration work at Meliadine, a gold mine site in Nunavut.
Specifically, the company wanted Stewart and her team to look at a number of drilling waste sites (small dumps of mud and clay) created during mine exploration.
“We went out and surveyed 25 waste sites created across a 20-year time span,” she said.
What they found was surprising and heartening—natural re-vegetation was occurring at all of the sites, with the older ones completely recovered and younger ones well on their way.
“We usually think of biological soil crusts as slow growing but what we saw here was surprising and it made me really happy!”
Realizing that Mother Nature was able to handle the waste sites, Stewart and Agnico Eagle shifted focus to tundra restoration work in some of Meliadine’s quarried areas. She said that these exposed gravel and rock substrates are more indicative of the landscape when a mine departs than drilling waste sites are.
In July 2019, Stewart and her team set up a trial comprised of four 15-metre-long rows that were dug out to approximate the natural tundra microtopography of the surrounding area, a topography known as hummock-hollow. Ten plots per row were given one of four treatments: intact tundra plugs, shredded tundra material, a combination of plugs and shredded material, and the control, which was no added material at all.
What’s a tundra plug? Imagine digging up a solid block of sod on your lawn about 16 inches square and about five inches deep—that’s a plug of sod.
“With those plugs, the whole soil ecosystem is there,” said Stewart. “We want to know if we move plugs of that size, do they maintain nitrogen cycling, their root systems and so on.”
To create the shredded material, tundra plugs were broken up and pushed through a metal sieve.
The goal is to see which plants survive the transplant best, survival rates by treatment type, which plants are effective colonizers and more. The plan was to revisit the site this summer (2020) and again in 2021 to survey and assess the trial. Sadly, COVID-19 travel restrictions have made that impossible, but all is not lost.
“We have a matching growth chamber trial at USask,” said Stewart. “We brought back some of those plugs, split them in half with one half in a substrate with no fertilizer and the other with fertilizer. They matured over a three to four month period then we broke them apart to see what happens when those plugs colonize outward—how do roots extend, for example.”
Restoration that works for people
At the heart of Stewart’s work is building bridges between community, landscape and industry.
“A lot of the research I do is working with industry and community,” she said. “I’m in an odd place, sitting outside of both, but being able to see the needs of both at the same time.
“Restoration is a science, yes, but it’s also really connected to people,” said Stewart. “We need to develop better processes of working collaboratively with local Indigenous people, from mining through to restoration.”
For Stewart, that means developing tundra restoration techniques that can be replicated by local communities once researchers like her are gone.
“I want to develop techniques that can be done with limited technology by local people,” she said.
In other words, restoration that can be done with what’s on hand without having to ship in specialized equipment, as well as teaching local people how to properly sample an area, do surveys, assessments and more.
As part of that effort, Indigenous youth are employed at the Meliadine restoration project as field assistants, and Stewart’s team has also developed education programs about the work for local school children.
“I truly believe in finding ways forward to help the land, ensure that it gets maintained and restored, and my interest in working with Indigenous communities comes from that place,” said Stewart.
“We need to think more about how we handle our land in Canada better and how we involve the people better—people who will be there when the mine moves away. They’re the ones who have to live with the fallout and if that land is going to provide what they want when the extraction is over.”
Agknowledge, December 2020