Arctic spiders may hold clues to global warming

By Alister Doyle, Environment Correspondent

OSLO (Reuters) - Reclusive spiders living in the Arctic may yield clues to the impact of global warming just like bigger, better-known predators such as polar bears, a researcher said on Tuesday.

Any disruptions to tiny Arctic spiders, little studied and living much of their lives under snow, could ripple through the food chain since they prey on insects and are in turn eaten by birds, said Michael Nickel of Stuttgart University in Germany.

Nickel is to study Arctic spiders during a U.N.-sponsored International Polar Year in 2007-08, a 60-nation project to probe polar areas on the front lines of climate change. There are about 70 species of spiders in Greenland alone.

"The effects of changes are more obvious in the bigger animals," such as polar bears or seals, Nickel told Reuters. But global warming "affects the whole environment and you have to look at the basic scale too."

"There is even a lot of knowledge and projects about plants but insects and spiders are a little neglected," he said.

Spiders adapted to living in the Arctic, with chill temperatures and little food, can take up to seven years to reach maturity, according to some studies. That compares to one to two years for similar species further south, he said.

Global warming, blamed by almost all scientists on a build-up of greenhouse gases from human use of fossil fuels, could help the Arctic spiders to grow faster in the short term. 

But, in the longer term, a melting of snow and ice might allow more southerly spider species to march northwards.

"In the first few years (Arctic) spiders might have better chances but as stable populations come up of new species the situation will completely change," he said.

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"I don't think that (Arctic) spiders will be winners (from global warming). The competition may be higher," he said. "But it's not yet clear what the effects will be."

Spiders are found throughout the Arctic. The wolf spider, 2.5 centimeters (1 inch) from leg tip to leg tip, is among the biggest.

"In the winter they hide under the snow where the climate is quite mild," he said. Nickel's project is one of more than 200 approved for Polar Year but he said he still needed to raise funds for field trips.

Arctic temperatures have been rising twice as fast as the world average in recent years, scientists say, apparently because darker ground and water, once exposed, soaks up more heat than ice and snow.