14 June 2007The New York Times
Many Arctic plant species have readily adjusted to big climate changes, repeatedly re-colonizing the rugged islands of Norway’s remote Svalbard archipelago through 20,000 years of warm and cool spells since the frigid peak of the last ice age, researchers say.
The finding implies that, in the Arctic at least, plants may be able to shift long distances, following the climate conditions for which they are best adapted as those conditions relocate 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 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 University who is involved with many studies of plants and animals already 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 and their communities,” 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.”
In the study, Norwegian and French scientists analyzed the DNA of more than 4,000 samples of nine flowering plant species from Svalbard, a craggy ice-draped group of islands halfway between the Scandinavian mainland and the North Pole. They found genetic patterns that could only be explained by the repeated re-establishment of plant communities after the arrival of seeds or plant fragments originating in Russia, Greenland, or other Arctic regions hundreds of miles away, the researchers said.
The team, led by scientists from the University of Oslo, described the findings in today’s issue of the journal Science.
The wide dispersal of the plant species presumably occurs through a combination of strong Arctic winds, driftwood or dirt carried in floating sea ice, and bird droppings, the scientists said.
Julie Brigham-Grette, a geosciences professor at the University of Massachusetts who focuses on the Arctic, 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,” Dr. Brigham-Grette 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, a scientist at the University of Oslo and the lead author of the paper, said that natural adaptability in the plants may be put to the test if the latest projections for rapid warming in the Arctic from the United Nations Intergovernmental Panel on Climate Change come 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 natural tendency toward sharp climate swings, she said. “A separate study needs to be done for more southern latitudes,” she said.
