Demystifying science | Forest fires: where do the animals go?

Every week, our journalist answers scientific questions from readers.

What is the impact of forest fires on wildlife? – Micheline Rivet

In the short term, most animals can escape the flames of wildfires. But certain species may be affected in the medium term, particularly birds that have already nested.

“People imagine that everything is going to die, but many species are capable of moving,” explains Steeve Côté, caribou specialist at Laval University.

Less mobile species, for example the porcupine, can smell the flames from very far away. “You need fires that progress very quickly to cause mortality in these species,” says Mr. Côté.

Cases similar to Australian koalas burned alive during fires are therefore rare here.

As the fires mainly occurred at the start of the season in Quebec, the birds had probably not yet nested, according to Mr. Desrochers. They have therefore not lost their chicks, which are born a little before mid-June at the earliest. “In British Columbia, where there were fires all summer, it’s probably worse,” says Mr. Côté.

Competition

Animals affected by fire, on the other hand, must re-inhabit new habitats. “In some cases, these are more territorial species, so there will be mortality linked to competition,” says Mr. Desrochers. This is a medium-term consequence. »

Other species, such as large ungulates like caribou or bears, take some time to get used to their new environment.

In the scorched lands, there are also winners. “The year following a fire, bird species take advantage of the burns,” says Mr. Desrochers. The most famous species is the black-backed woodpecker. It is a woodpecker that eats the larvae of longhorned beetles. Longhorn beetles love burns, they feed on the remaining sap. They smell the fire. Nightjars also love burns for similar reasons. Grazers like hares benefit from the abundance of low vegetation which is the first to regrow. They like the residual thickets that fires often leave behind. »

The fires of yesteryear

And in the long term? “The species that inhabit the boreal forest have been here for a long time,” says Mr. Desrochers. They have had much worse fire seasons than now. Yes, this year is the worst we know, but that’s because the data is only about fifty years old. »

Some researchers are working on forest fires from past centuries and millennia. Dominique Arseneault, of the University of Quebec at Rimouski, for example, studied the rings of trees injured by fire along two taiga roads in the Far North. “We can go back 200 years,” says Mr. Arseneault, who is just at Radisson for a sampling campaign.

Are this year’s fires the worst in 200 years? “Yes, but not by much,” said Mr. Arseneault. There are peaks of fires every 15-20 years. In 1922 there was a slightly smaller peak than this year. We now have to see if we will have more frequent peaks. I would say that we will have enough data to say this within ten years. »

To go further, it is necessary to study the coals present in the lake sediments. Adam Ali, from the University of Montpellier, has been working for 20 years with colleagues from the Université du Québec au Témiscamingue on this issue. “We are less precise than with tree rings, but we can certainly say that the fires of the medieval climatic optimum, when the Vikings colonized Greenland, were much more intense in Quebec” than those we know now , says Mr. Ali.

The forest biologist from Montpellier is just about to leave for Caniapiscau. “We are going to try to find a site where we can study fire-damaged trees and coal in lake sediments,” says Mr. Ali. With this, we will be able to create a slightly more precise history of forest fires in Quebec. »