Many Arctic plant species have readily adjusted to big climate changes, repeatedly recolonizing the rugged islands of the remote Svalbard archipelago off Norway’s coast through 20,000 years of warm and cool spells since the frigid peak of the last ice age, researchers report in today’s issue of the journal Science. Their finding implies that, in the Arctic at least, plants may be able to shift long distances to follow the climate conditions for which they are best adapted as those conditions move under the influence of human-caused global warming, the researchers and some independent experts said.

Some experts on climate and biology who were not involved with the study, which was led by scientists from the University of Oslo, said it provided a glimmer of optimism in the face of generally bleak scientific assessments of the vulnerability of ecosystems to the atmospheric buildup of greenhouse gases. Terry L. Root, a biologist at Stanford who has been involved with many studies concluding that plants and animals are measurably feeling the effects of human-driven warming, described the Svalbard research as “great news.”

“The large number of documented changes has created quite a concern about the fate of many species,” Dr. Root said. The new study, she said, shows that “some Arctic plants, and hopefully vegetation in other areas, apparently are able to respond in a manner that compensates for the rapid warming.”

Norwegian and French scientists analyzed the DNA of more than 4,000 samples of nine flowering plant species from Svalbard, a group of islands between the Scandinavian mainland and the North Pole. They said they found genetic patterns that could be explained only by the repeated re-establishment of plant communities after the arrival of seeds or plant fragments from Russia, Greenland or other Arctic regions hundreds of miles away.

The wide dispersal of the plants presumably occurs through a combination of Arctic winds, driftwood or dirt carried in floating ice and bird droppings, the scientists said. Julie Brigham-Grette, a geosciences professor at the University of Massachusetts, said the findings were consistent with research from Alaska showing that forests had extended farther north during a period, warmer than the present, that peaked around 11,000 years ago.

“As the proper habitat is available, plants will survive,” she said. “I have not seen this demonstrated so clearly as it is in this paper. If dispersal is not a limiting factor, then maybe the rate of warming ongoing in the Arctic will not be a limiting factor in plant survival in distant places.”

Inger Greve Alsos, the study’s lead author, said natural adaptability in the plants might be tested if the projections for rapid Arctic warming from the United Nations Intergovernmental Panel on Climate Change came to pass. She also cautioned that the evidence for resilience and long-distance mobility in Arctic plants could be the exception, not the rule. The ability of Arctic flora to disperse widely is probably an evolutionary consequence of the region’s tendency toward sharp climate swings, she said.
(By ANDREW C. REVKIN, PLanet Ark, 15/06/2007)