The Mountain Avens emigrated
to Svalbard from Russia.
Credit: Bjørn Erik Sandbakk
As the Arctic warms up, will plants migrate fast enough to find suitable habitats?
The answer to the question may be hidden in what has already happened during previous dramatic warming episodes, like when ice sheets retreated and exposed new land.
The assumption, of course, is that plant dispersal occurs at a glacial pace, marching seed by seed up a mountain slope, or yard by yard across a newly exposed glacial outwash. And that could mean extinction for many plants that won’t reach nurturing habitats, if global warming shifts habitat zones as fast as projected under some climate models.
But scientists say plants may be far trickier travelers than we humans realize. In a study published June 15 in the journal of Science, a team of Norwegian researchers found many different regions colonized the extremely remote Svalbard archipelago several times over the past 20,000 years since the Last Glacial Maximum.
In some cases, their seeds traveled thousands of miles over deep ocean — via wind or drifting ice — to nail a new niche on the Svalbard tundra.
Reseracher and graduate student Inger Greve Alsos led a team that analyzed “genetic variation in over 4,000 samples of nine flowering plant species native to the Arctic and found that these plants have migrated, probably via wind or sea ice, from all possible neighboring source regions,” according to a summary of the study.
The Cloudberry also emigrated
to Svalbard from Russia.
Credit: Bjørn Erik Sandbakk
“Climate warming is expected to cause the distribution area of many plant species to shift northward in the Northern Hemisphere,” Alsos and her eight co-authors wrote in “Frequent Long-Distance Plant Colonization in the Changing Arctic,” published June 15 in Science.
“The composition of future ecosystems will critically depend on the long-distance dispersal capabilities of individual species.”
The authors figured Arctic plants have probably evolved the ability to disperse over long distances, using wind, driftwood, birds and mammals for rides to new sites for potential colonies.
More Mountain Avens
Credit: Bjørn Erik Sandbakk
“The recurrent glacial cycles have probably selected for a highly mobile arctic flora. In addition, some dispersal vectors may be particularly efficient in the Arctic as a result of the open landscape, strong winds, and extensive snow and ice cover. The high levels of genetic diversity found in several species previously studied in Svalbard are also consistent with multiple dispersals. . . .
The key wasn’t so much whether the plant can find a way to reach the new habitat, but rather whether the plant can germinate and sink roots and thrive once it arrives.
“The authors propose that, at least for the Arctic, it may be appropriate for researchers to assume that plants can migrate easily in response to climate change, provided that suitable habitat is available,” according to an article summary.