Dozens of plant species in Alaska, Yukon likely to spread north due to climate change, says study

Dozens of plant species across the Yukon and Alaska — some found nowhere else in the world — are predicted to creep north over the next two decades due to climate change, according to new projection models.

And while that may be a good thing for some species, the authors of a new report say other plants may be met with shrinking habitat and, eventually, have nowhere left to go.

Researchers, in a paper published in the Diversity and Distributions scientific journal earlier this year, selected 66 plant species found in northwestern North America, including Yukon Podistera, Yukon wormwood and bristle-pointed iris.

They then modelled how each species' habitat range would be affected by a "moderate" climate-change scenario, which would see average temperatures increase by about 2 C by 2040.

"The basic question is, where are the species right now, and what happens to them 20 years into the future?" lead author Tobi Oke, a post-doctoral research fellow with Wildlife Conservation Society (WCS) Canada, said in an interview.

Researchers predict that more than 80 per cent of plant species will be found, on average, about 140 km further north by 2040. What that means for each plant varied; for up to 20 per cent of species, it would mean an increase in their total areas of distribution — they would gain ground. More than 60 per cent of species, however, would lose ground and experience range contractions.

That could ultimately lead to a "nowhere-to-go" scenario for some plants, Oke said.

"Some species are already right at the edge of the continent, right? So if they are trying to escape warming from where they are and they have to move further — well, what's further? That's just the Arctic Ocean," he explained.

"They have nowhere to go, so they are likely going to disappear."

Other northern plant species, he added, may also be boxed in by topography, already growing, for example, at or near mountaintops with little room left to flee.

Some species will be able to adapt faster

Chrystal Mantyka-Pringle, another author on the paper and co-director of WCS Canada's northern boreal mountains program, said researchers chose to look at climate change's potential impact on plants because they serve as a "baseline" or foundation for other species.

While the Yukon currently has what she described as a "healthy" level of biodiversity, Mantyka-Pringle said it was important to pay attention to any potential changes sooner rather than later.

"[It's] not just thinking about today … but thinking of what [biodiversity] will look like in 40 years," she said.

"There will be winners and losers when it comes to species and biodiversity. Some species are able to adapt faster and they're more resilient to change whereas others aren't."

The differences in how species react to climate change — according to the paper, some plant species are at risk of losing up to 90 per cent of their habitat by 2040 while others are anticipated to thrive in their new conditions — can help with next steps, Oke said.

"If we look at everything, it's easy to say, well, I mean, 'This is just way too much to deal with, what can we do?' Knowing that different species are going to be affected at different scales can help us manage this situation," he said.

Possible actions, Oke and Mantyka-Pringle suggested, include identifying areas more resilient to climate change and ensuring they're protected, thereby creating "safe havens" for the plants within. Translocating at-risk plants is also an option, they said, although that comes with a series of logistical considerations.

On the research front, Oke said he'd like to next look at how climate change could impact animals as well as "environment parameters" — forest fires, for example —  and how the potential changes in plants laid out in the paper could factor into that.

Having that knowledge could be used to shape conservation decisions, he said, especially when the potential future loss of a handful, or even one, species could be enough to tip the balance.

"Look at it this way," Oke said. "If you have a sweater and you see loose threads, if you keep pulling the loose threads eventually you're going to have an ugly sweater, right?

"So think of your ecosystem like that."