Plant communities in the Arctic are changing along with the climate, study finds

A recent study has found that climate change is altering Arctic plant communities, with some species declining in response to warmer temperatures, while others flourish. 

The study, published in the journal Nature last week, looked at over 2,000 plant communities across the Canadian Arctic, Alaska, and Scandinavia over the course of four decades.

Fifty-four researchers from 50 different institutions collaborated on the project. They found that although the number of plant species across the 45 study sites remained the same over time, the species of plants found at each site changed, with plant turnover increasing due to climate change. 

"So around 60 per cent of the plots … experience this sort of turnover, this change in the abundance of the species and exactly which species are growing within those plots," said Isla Myers-Smith, one of the paper's authors. 

"And one of the types of changes that was going on across all these sites was that some sites we are gaining species and other sites we are losing species."

Sites that underwent more warming over the course of the study gained new species, said Myers-Smith. However, certain species that responded well to warming temperatures, caused declines in others. 

Shrubs have become a dominant species at many of the study sites, but due to their height, shrubs push out shorter species by limiting their access to sunlight. 

Myers-Smith, a global change ecologist at the University of British Columbia, began managing one of the study sites in the Yukon's Herschel Island-Qikiqtaruk Territorial Park in 2009. She and her team have been monitoring plant diversity and abundance on the island ever since.

"I get to go each summer up to Qikiqtaruk and we monitor the plots in the end of July, fighting the mosquitoes to collect these really valuable data on how ecosystems are changing."

In Qikiqtaruk, Myers-Smith and her team found that species of shrubs, sedges and particularly, grasses increased over time, while lichen decreased. This ecosystem shift could impact other wildlife on the island. 

'There will always be winners and losers'

Donald Reid, a retired biologist with the Wildlife Conservation Society Canada, says the impact of more shrubs, sedges and grasses in Qikiqtaruk depends on the species. 

"Changes generally in ecosystems are never sort of blanket good or bad for anything in particular," he said. "There will always be winners and losers."

Some species, like beavers, prefer this type of vegetation, he said. 

"They expanded out of the Mackenzie Delta along the Yukon North Slope into some of the rivers there because they now have a much more abundant food source to get them through the winter," Reid said. 

Reid says the impacts of these changes are also evident in migratory birds, particularly ground nesting birds that prefer open landscapes and shorter vegetation, like the American Golden Plover. 

"Their numbers on Qikiqtaruk have gone down dramatically in the last four decades," he said.

A changing landscape

Park rangers in Qikiqtaruk have their own monitoring program for plants on the island and they supported Myers-Smith and her team during their research.

Richard Gordon, an Inuvialuk who is the senior park ranger at Herschel Island-Qikiqtaruk territorial park, has watched the island change before his eyes during his 25 years as a ranger. 

"Each and every year we go out there, there's going to be something [that's] changed."

He's felt the summers get warmer over time, watched ice recede and witnessed the turnover of various plant species, with cottongrass dominating the landscape when he first arrived, and then shrubs quickly populating the island in recent years. 

Those changes, he says, are concerning to the Inuvialuit in the area, because of the potential affect on the migrating animals that they rely on, like caribou.

One of the most significant environmental changes Gordon has witnessed was a landslide in August 2023.

"It sure opened my mind and eyes that these things are happening…. You have to prepare for them. It totally changes your perspective on how you're going to observe into the future," he said.

Moving forward, Myers-Smith wants to continue studying how these changing ecosystems are affecting the entire tundra food web. Recently, she received funding for a research project to study the impacts of tundra vegetation not just in Qikiqtaruk, but across the entire territory. 

"We're trying to … pull together that story of how these changing tundra ecosystems, the changing permafrost thaw … the climate itself, heat waves, how that's all feeding back to changing these Arctic food webs and the wildlife that depend on these ecosystems."