Yukon

�Թϱ�� researcher explores impact of climate change on food security in the Yukon

Christopher.Sorensen — Fri, 03 Sep 2021 19:41:33 +0000

�Թϱ�� researcher explores impact of climate change on food security in the Yukon

Christopher.Sorensen Fri, 09/03/2021 - 15:41

Cutline

The climate crisis is threatening northern ecosystems and traditional food sources, including caribou in the Yukon (photo by DeAgostini via Getty Images)

Sharon Aschaiek

Topic

Our Community

Anthropology

Climate Change

Research & Innovation

Sustainability

�Թϱ�� Mississauga

Yukon

The intensifying climate crisis will have a distinct impact on Canada’s North – and one University of Toronto researcher wants to understand what this could mean for the food security of people living in the Yukon.

Accelerated warming caused by greenhouse gas emissions is melting snow cover, thawing permafrost and causing rising sea levels. That, in turn, threatens local ecosystems and their food sources, including those traditionally consumed by Indigenous Peoples such as caribou, deer and salmon. At the same time, increasing temperatures are altering the territory’s geographical landscape, damaging roads and airstrips that serve as critical food-delivery routes for these largely remote communities.

What do these climate trends mean for the food security of the region’s citizens, including its historical rightsholders – the 14 First Nations communities and transboundary Indigenous groups?

Iva Seto

That is the question at the heart of a new research initiative being co-led by Iva Seto, a post-doctoral researcher in the department of anthropology at �Թϱ�� Mississauga. Under the supervision of Associate Professor Tracey Galloway, Seto is partnering with the Yukon government and Yukon University to assess the scope of the threat.

“This project is about making sense of the impacts of the long-duration crisis of climate change and providing leaders with actionable information about food security,” says Seto, whose work is being facilitated by a Canadian Institutes of Health Research’s Health System Impact Fellowship, which supports research into critical health-care challenges being tackled by health system organizations.

“It aligns with my own passion for doing work that improves population and public health.”

For her doctoral thesis at Victoria University of Wellington’s School of Information Management, Seto examined the role of expert advisory groups in responding to Canada’s outbreak of SARS in 2003. She was motivated to apply her expertise to the Yukon’s climate challenges after reading two government reports published last fall: Our Clean Future, outlining territorial action on addressing climate change; and Putting People First, a comprehensive review of public health and social services.

At the outset, Seto will gather and synthesize information on local climate change effects from multiple sources, including academic literature, government stakeholders and food security non-governmental organizations. To contextualize the data, she will then interview Yukoners, including Indigenous Peoples, about their lived experiences of food insecurity.

In phase three, she will present her overall research findings to community members and collect their input. She will then present a final report of recommendations to the government to help it achieve its climate goals, which include reducing greenhouse gas emissions to 45 per cent below 2010 levels by 2030, generating 97 per cent of electricity from renewable sources by 2030, minimizing the negative impacts of climate change and building a green economy.

The urgency of the project is underscored by the United Nations’ comprehensive new report, Climate Change 2021: The Physical Science Basis. The report indicates global warming is unequivocally caused by human activity; is widespread, rapid and intensifying – and will cause more severe heat waves, hurricanes and other climate events that will threaten all life forms. The almost 4,000-page report calls for immediate, deep and sustained reductions in carbon dioxide emissions in the coming decades to slow down or stop climate change.

Galloway, meanwhile, has studied how our overheated planet creates special complications for the food security of those living in the North. Food may be delivered by trucks via annually rebuilt ice roads, but these roads are now melting faster each year.

Airplanes also bring in food, but the airports are small and under-resourced – and winter weather conditions affect their reliability. At the same time, she notes, citizens in these fly-in regions face the highest food costs in the country. These factors contribute to the finding by PROOF, �Թϱ��’s food insecurity policy research team, that Nunavut, the Northwest Territories and the Yukon have the highest rates of food insecurity in the country.

“There has been local community-level work done in Indigenous communities for years around food security,” Galloway says. “The goal of this project is to aid government efforts to enable access and remove boundaries to food, and to support and build on the amazing work being done by communities.”

Using tree rings, �Թϱ�� researchers measure history of mercury contamination in Yukon

Christopher.Sorensen — Mon, 09 Nov 2020 17:06:30 +0000

Using tree rings, �Թϱ�� researchers measure history of mercury contamination in Yukon

Christopher.Sorensen Mon, 11/09/2020 - 12:06

Cutline

Researchers at �Թϱ�� Mississauga examined tree rings in Bear Creek, a former mining site near Dawson City, Yukon, to trace the history of mercury contamination in the area (photo by Trevor Porter)

Topic

Research & Innovation

Sustainability

�Թϱ�� Mississauga

Yukon

By examining clues hidden beneath tree bark, a research team from the University of Toronto Mississauga is recording the history of pollution in Canada’s North.

Paleoclimatologist Trevor Porter (pictured), an assistant professor of geography, geomatics and the environment who uses tree rings to understand past climate, recently teamed up with Igor Lehnherr, a fellow assistant professor who studies contaminants, and master’s student Sydney Clackett to investigate annual pollution levels at an old gold mining site in the Yukon. They were particularly interested in the “heavily polluted” Bear Creek area, a busy gold mining town that operated from 1905 to 1966 just outside Dawson City, Yukon.

One of the methods used in the past to extract gold from river gravel was to add mercury, which binds to the gold to help separate it from the sediment. The deposits were then heated to separate the gold and mercury. The process of burning off the mercury meant some of it was diffused into the atmosphere, where trees would “breath it in” during their growing season, according to Porter.

“Especially in the north, trees are growing in this really temperature-limited environment so we can look at the rings and almost interpret it like a climate record, going back in time,” he says.

Porter and the other researchers took core samples from 15 trees growing in the area to see if the rings could provide a year-by-year account of atmospheric mercury levels created by past local mining operations. Core samples from an area unaffected by local mining operations were also collected as a control site.

The team found that the trees at Bear Creek not only hold a record of mercury levels, but those changes in levels match, precisely, the known activities at the site. Their findings were recently published in Environmental Pollution.

�Թϱ�� Mississauga master’s student Sydney Clackett collects a bore sample from a tree at Bear Creek, a former gold mining site in the Yukon. The samples were used to measure past concentrations of atmospheric mercury in the area (photo by Trevor Porter)

“We were just amazed when we saw this big spike in mercury take off, especially when operations at the site started expanding,” Porter says. “Trends on this site were just orders of magnitude greater than what was happening naturally.”

In 1923, for example, there was a merger of all major Klondike mining operations and more ore was brought to Bear Creek for processing. That year, researchers observed a “rocket ship” trend in the mercury data. By contrast, as operations started to wind down in the 1940s and 1950s, there’s a precipitous decline in mercury concentrations. The fastest rate of decline appears in 1966, when the site closed.

“I was amazed at how closely it corresponded to what we could gather from the historical record,” Porter says, adding the research provides compelling evidence that this is a reliable method to track concentrations of local atmospheric mercury. “It elevates the idea that tree rings are an important archive for studying past changes in mercury.”

There’s not a lot of global data about changes to atmospheric mercury, Porter adds. While there is some monitoring in highly urbanized areas, the data only goes back about 30 years. �Թϱ�� Mississauga researchers, meanwhile, were able to analyze 151 years’ worth of data using tree rings.

The “Gold Room” at the Bear Creek site where mercury was used to extract fine gold from the placer ore (photo by Trevor Porter)

Although levels of mercury recorded at Bear Creek slowly came down to baseline levels, those baselines have been increasing over the past decade. Porter says that an uptick in atmospheric mercury has been observed in two other sites in the Yukon and Northwest Territories, and has recently been confirmed by other records, including lake sediment in Alaska. That increase in mercury has been linked to rising emissions in Asia (mercury is not used in modern mining practices in Yukon).

Porter says there are international treaties to reduce mercury pollution and, while there’s been a lot of progress, “we know that’s not happening everywhere. Some still use dirty energy sources and other industries emit mercury.”

A larger network of sites is needed to better understand these regional increases and determine what is happening, according to Porter. He says he’s already looking additional sites in Yukon and the Northwest Territories.

“We’re scaling up our efforts to better understand recent trends in the environment.”

A harried life: �Թϱ�� researchers study stress in snowshoe hares, apply it to humans

ullahnor — Tue, 02 May 2017 16:31:33 +0000

A harried life: �Թϱ�� researchers study stress in snowshoe hares, apply it to humans ullahnor Tue, 05/02/2017 - 12:31

Don Campbell

Author legacy

Don Campbell

Topic

Pretty much everything in the boreal forest is trying to eat the snowshoe hare.

It's preyed upon by Canadian lynx, foxes, coyotes and various birds. Red squirrels and Arctic ground squirrels even kill its babies.

It’s no wonder that, with grim odds of survival, the snowshoe hare experiences stress. �Թϱ�� Scarborough researchers are looking at the role of stress in snowshoe hares and what traits baby hares inherit from their stressed-out moms.

They're looking at whether stress triggers programming effects or changes in gene function for hare offspring, and they're hoping the hares may provide some answers for stressed-out humans and their babies.

“The idea is that if this effect happens in snowshoe hares, it may also be at work in other organisms,” says Rudy Boonstra, a professor of biology at �Թϱ�� Scarborough.

Researchers work out of the Kluane Lake Research Base in Yukon without electricity and running water while they study snowshoe hares

Boonstra has been doing field research in Canada’s north for more than 40 years and helped co-author a comprehensive book on the boreal forest ecosystem. In the early 1980s, he started thinking about the role stress plays in natural environments, particularly in how ecosystems are organized.

Snowshoe hares followed a somewhat predictable 10-year population cycle so they made good candidates to study the indirect effects of stress, Boonstra says.

“The evidence up until that point was that predators were calling the shots,” he says. “Once the hare population was abundant, predators were critical in driving down their numbers.”

During the decline phase of the population cycle, which lasts about two to three years, pretty much every snowshoe hare dies at the “tooth or talon” of a predator, says Boonstra. So the question became whether the hares are smart enough to know that a predator was likely to kill them.

“If you look at the stress levels they’re experiencing, clearly, they do,” he says.

Not only do hares show signs of stress in their blood and energy levels, that stress also influences how they reproduce. Past research in Boonstra’s lab has found that stress experienced by mothers can be inherited by their offspring. What’s more, during periods of very high predation, which happens at the peak of the hare population cycle, the number of litters per summer begins to decline.

“You would think they would be breeding like mad since they’re being killed like mad, but in fact it’s the opposite,” he says. “The fear reduces reproduction.”

Biology Professor Rudy Boonstra near Kluane Lake Research Station in Yukon (photo courtesy of Rudy Boonstra)

Boonstra is part of a larger team affiliated with �Թϱ�� Scarborough’s Centre for the Neurobiology of Stress and the Centre for Environmental Epigenetics and Development that looks at how the brain and nervous system are affected by stress.

He is trying to determine if there are programming effects that somehow get encoded in hare offspring. In other words, do mothers during intense periods of high predation pass something on, and are their offspring fundamentally different than those whose mothers didn’t experience the same levels of stress?

And, he wonders, are there lessons for humans, too?

“A pregnant mother during war time doesn’t know if she will survive so she’s experiencing an enormous amount of anxiety,” he says. “We want to know whether that anxiety passes through the placenta, and if so, does it program the child in a certain way.”

Sophia Lavergne, a PhD researcher at �Թϱ�� Scarborough, is also studying snowshoe hares. Affiliated with Associate Professor Patrick McGowan's epigenetics lab, she's taking a deeper look at the long-term effects of stress on showshoe hares.

Sophia Lavergne, a PhD student at �Թϱ�� Scarborough, is studying snowshoe hares to explore the long-term consequences of stress (photo courtesy of Sophia Lavergne)

She travels to the Kluane Lake Research Station in Yukon each year – for two weeks during the winter and four months during the summer – to study what baby snowshoe hares inherit from their moms.

“We know a lot about stress in the lab, and it’s always assumed to be negative. But, a lot of this stress may be preparatory for the hares,” she says, adding that it may help offspring adapt for life in a harsh environment. “It’s really important to test this in a natural system where there is a host of different stressors like fluctuating temperatures, predators, food scarcity and other challenges in the environment.”

Yukon

�Թϱ��� researcher explores impact of climate change on food security in the Yukon

Using tree rings, �Թϱ��� researchers measure history of mercury contamination in Yukon

A harried life: �Թϱ��� researchers study stress in snowshoe hares, apply it to humans

Read more about Lavergne's research

�Թϱ�� researcher explores impact of climate change on food security in the Yukon

Using tree rings, �Թϱ�� researchers measure history of mercury contamination in Yukon

A harried life: �Թϱ�� researchers study stress in snowshoe hares, apply it to humans