As fires from coast to coast scorch vast swaths of forest, sometimes altering it irreversibly, experts are looking at an often overlooked victim of the fires: wildlife.
Spring fires, like the ones currently burning across the country, are unusual and may affect multiple species, warned Karen Hodges, professor of biology at the University of British Columbia’s Okanagan campus.
“If the tree with a nest burns down, those eggs or chicks obviously won’t survive. The adults may be able to escape the fire, but the chances of them breeding elsewhere are unlikely this year. I think an immediate impact is that many individuals will not breed this year. Some will die,” she explained in a recent interview.
“Obviously animals that can walk away from the fire will. But that depends on how fast the fire is moving – whether the animals can distance themselves. It’s really hard to assess that. »
Emergency Preparedness Minister Bill Blair said on Monday more than 47,000 square kilometers had burned so far this year, with more than 430 wildfires raging across the country. Canada is experiencing its worst wildfire season in the 21st century, he added.
Ms Hodges fears things will only get worse, with months of higher temperatures ahead.
“I expect a lot of animals to be moved or killed,” she said. I expect some populations in some areas to be extinct, or small, for decades to come as a result of this year’s burn. »
Smoke Effects
Matthew Mitchell, a land and food systems research associate at the University of British Columbia, pointed out that carbon monoxide and particulate matter in smoke from wildfires can have “acute” effects on the health of animals, some of which may not be seen for years.
“It can affect their lungs, change blood chemistry, reduce oxygen levels, and so you can also have effects on the immune system,” he said.
“These kinds of things can lead to changes in demography, or also in the survival, growth and reproduction of animals. »
Wildfire smoke could also lead to behavioral changes, including how active animals are, whether they seek mates and how much they sing, he said. Orangutans and gibbons affected by smoke from wildfires in more tropical areas have been found to make less noise than those not exposed, he said.
Scientists have observed that marten fetuses are negatively affected by wildfire smoke, Mitchell said. He adds that the fires could impact pregnant females or their newborns just as they affect humans.
Positive effects, in certain contexts
A study published in February in the journal Ecology Letters examined the regenerative power of wildfires and concluded that not all news is bad for wildlife.
She found that some ecosystems see “species richness” after a fire, with birds and mammals seeing an increase in diversity.
“It remains to be seen how ecological and evolutionary drivers translate into effects on animal richness, but our results show that cumulative effects are surprisingly positive, at least for bird and mammal richness,” the paper says. Canadian, American and European researchers.
Animals that have the ability to reproduce faster do better in a fire-prone environment, the study notes. But fires in areas where they don’t occur regularly wouldn’t be particularly beneficial: “In these ecosystems, fire is more of a modern threat than an important process to sustain, and recent fire activity in these systems is not is not a probable factor of wealth”, we qualify.
While animals in Canada have adapted to the wildfires that are a natural part of the ecosystem, Mitchell pointed out that “megafires” that occur repeatedly change the fire regime. There is less time between fires, which makes it more difficult for the forest to regenerate.
And it’s not just birds and land creatures that are affected by wildfires. “Whales and dolphins, because of the way they breathe, often come up and exchange almost all the air in their lungs as they breathe,” he said. They might also be more sensitive. »
Mr Mitchell says he worries most about endangered species. “I expect we will lose some species, if these kinds of smoke events and wildfires continue to increase,” he said.
“Predicting what exact species it is would be difficult, but I expect there will be casualties. »
On the other hand, some species may benefit, but he said it was difficult to predict which ones. »
Ms Hodges said animals such as Canada lynx, marten, fisher and snowshoe hare need mature forests while others, such as owls, need large trees with cavities to nesting. But when fires burn these trees, it takes decades for them to become mature forests again: “These will be lasting changes. »