How climate change is affecting dragonflies in Canada and around the world

TORONTO – Dragonflies are some of the most resilient insects on the planet. They have been on this planet for more than 200 million years and inhabited every continent except Antarctica.

Experts say climate change is allowing many species of dragonflies in Canada and around the world to thrive and expand their ranges, but arctic cold-adapted dragonflies are likely to encounter them. difficult.

A report from the British Dragonfly Association released on Tuesday found that since 1970 dragonflies in the United Kingdom and Ireland have expanded their range and spread northward.

About 40% of species have increased in number, while 10% have decreased. In addition, six species of dragonflies that only exist in mainland Europe have colonized the British Isles since 1996.

While similarly comprehensive data are lacking on dragonfly species in North America, experts told that researchers have observed similar trends in Canada and the US.

Michael Moore, an evolutionary biologist at Washington University in St. Louis, Mo., calls dragonflies “an important indicator species” when measuring climate change.

“You tend to see more dragonflies in these really warm environments than in cold ones,” he told on Wednesday.

“In terms of how dragonflies will deal with climate change… some of them will seem like they’re doing better in places like the US and Canada because there’s more room for those that have adapted to the heat. higher altitude.”

Many species of dragonflies are called “generalized” species by biologists. That means these species are well suited to a wide range of habitat conditions.

“Those are species that are expanding their range,” said insect biologist Manpreet Kohli, a researcher at the American Museum of Natural History in New York City.

As dragonflies expand their range northward, Kohli says they can act as invasive species and negatively affect biodiversity.

“Generalists, a lot of times, can like invasive species when they are so dominant that they don’t let other species thrive,” says Kohli.

But not all dragonflies can be so lucky. An example of a dragonfly that can struggle is Somatochlora sahlbergi, also known as the treeline emerald. This species is adapted to the cold climates of the Yukon, Alaska, parts of Scandinavia and Russia.

When Kohli and her colleagues went to the Yukon to study the species in 2015, they found they couldn’t find the species in the areas where they expected to find it. Additionally, Kohli noticed that other species of dragonflies were moving into the emerald habitat in the trees.

“This species could be in particular danger because of climate change, especially if it is replaced by other competing species moving from the southern ranges,” she said.

Climate change is having more impact on the geographical distribution of dragonflies. Moore is the lead author of a study published in July showing that warmer temperatures are affecting the color of the wings of dragonflies in North America.

“What our research shows is that there are really consistent ways that dragonflies here in the United States and Canada seem to have adapted this wing color to attract mates,” Moore said.

Moore and his colleagues found that dragonflies are losing the black color of their wings, which could make it harder for these species to attract mates.

“There are all sorts of things dragonflies have been trying to adapt to throughout their long history,” says Moore.

“The fact that you know we’re probably catching some of these dragonflies now, that’s pretty scary for the rest of us. We don’t know how we can adapt compared to one. organisms have existed for about 200 million years.”


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