Arctic ecology: Tundra's burning

Published online 2 September 2009 | Nature 461, 34-36 (2009) | doi:10.1038/461034a

News Feature

Arctic ecology: Tundra's burning

Lightning and fires on the Arctic tundra seem to be on the rise. Jane Qiu meets the researchers learning from the scorched earth in Alaska.

Jane Qiu

More than 20,000 lightning strikes were recorded on the North Slope of Alaska in 2007. Some struck the vast stretches of lakes; some hit the treeless tundra. And one of them torched into life the largest and longest-lasting tundra fire recorded in the state's history. The blaze, which started near the Anaktuvuk River on 16 July, burned 7,000 hectares a day at its peak, and eventually consumed 100,000 hectares, an area larger than that of New York City. It finally stopped burning in early October, smothered by thick snow.

Two years later, the scars left by the blaze are all too apparent from a helicopter circling over the region. So too is the area's quick recovery. Tussock grass, the predominant vegetation in northern Alaska, sends up vibrant green shoots from scorched meristems. Its white flowers bloom over the deeply blackened soil like a dust of snow, stretching to a hazy horizon. It is surprisingly beautiful.

This is more than a view of nature's swift destruction and renewal; it is also a site of intense research. "The Anaktuvuk River fire is a large natural experiment," says Gaius Shaver, an ecologist at the Marine Biological Laboratory in Woods Hole, Massachusetts, who leads an effort funded by the US National Science Foundation to study the fire's environmental impact. "It provides an unprecedented opportunity to study how the entire ecosystem responds to major disturbances." Scientists from ten research groups have been flying into the burned area from the nearby Toolik research station to assess how the fire has shifted the carbon balance and affected the hill slopes, valleys, streams and lakes in the region.

Understanding the effect of fires on the Arctic tundra may become more important as the climate gets warmer. Tundra fires used to be rare events, but higher temperatures and a more arid climate seem to be changing that. According to the US Bureau of Land Management in Washington DC, the frequency of lightning on the North Slope has increased tenfold in the past decade. And many researchers fear that the increased lightning may increase the fire risk. Of the 26 recorded fires on the North Slope since 1950, close to one-third has taken place in the past three years — and the region burned in the Anaktuvuk River fire alone constitutes more than half of the total burned area.

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