Researchers from Trent University are immersing themselves in forests and streams in northwestern Ontario to understand how forestry practices and climate change affect brook trout populations and freshwater ecosystems.
The team is working in the Walkinshaw and Wolf watersheds, northeast of Thunder Bay. They are focusing on headwater streams, which are small rivers that feed larger waterways across the Great Lakes.
“Northern freshwater ecosystems are currently experiencing major disturbances, two of which are forest harvest and climate change. One of the effects of climate change is an increase in water temperatures. And the consequences of these predicted increased temperatures on the stream ecosystem are still unclear,” said PhD student Celeste Milli, who is leading the fieldwork.
Brook trout, a cold-water species highly sensitive to temperature fluctuations, serve as an important indicator of ecosystem health.
“They thrive in low temperatures. While they start to suffer even around 19, 20 degrees,” said Milli.
The fieldwork involves researchers using a combination of traditional and advanced techniques, including electrofishing, which briefly stuns fish so they can be measured, counted and released. They also use environmental DNA sampling. Water collected from streams contains DNA shed by fish and other organisms, allowing the team to estimate populations and assess food webs without disturbing the ecosystem. Milli also collects samples of insects and biofilm — a thin layer on surfaces underwater that has bacteria, algae and fungi — to better understand how forest management and temperature changes influence the aquatic food chain.
The project is supervised by Andrew Tanentzap, Canada Research Chair in Climate Change and Northern Ecosystems.
“Because we’re working with the Canadian Forest Service and the Department of Fisheries and Oceans on this research, the hope is that we can use this research to better inform forest management practices of how best to protect and conserve aquatic biodiversity and freshwater health,” Tanentzap said.
He said the study builds on previous research in New Brunswick and near Sault Ste. Marie. The research is conducted in partnership with the Canadian Forest Service, Fisheries and Oceans Canada and Ontario’s Ministry of Natural Resources.
Milli said the research could help inform science-based policy decisions in Canada’s northern forests, ensuring that both forest ecosystems and freshwater resources remain resilient in a changing climate.
She said she hopes the team will have results to share with federal partners in the next few years.
