July 26, 2011

Wildfires Could Change Ecosystem In Yellowstone

A U.S. study said on Monday that climate change is likely to cause more frequent wildfires and may transform the forests and ecosystem of the iconic Yellowstone national park in the next few decades.

The study, published in the Proceedings of the National Academy of Sciences (PNAS), said Yellowstone will be filled with open spaces, grasslands and forests populated by different kinds of fir trees and shrubs in the future.

The study said that fires like the historic one in 1988 that ate up 1,200 square miles of forest will become the norm by 2075.

The researchers made the forecasts by examining climate data from 1972 to 1999 and created statistical patterns by combining those data with figures on the size and frequency of Rocky Mountain fires in the same period.

The team projected how climate change of about two degrees Fahrenheit annually, combined with the snowmelt, would affect fires in Yellowstone through 2099.

"What surprised us about our results was the speed and scale of the projected changes in fire in Greater Yellowstone," professor Anthony Westerling of the University of California - Merced said in a statement.

"We expected fire to increase with increased temperatures, but we did not expect it to increase so much or so quickly. We were also surprised by how consistent the changes were across different climate projections."

The study said that after 2050, the average annual area burned was about 400 square miles.  The fire pattern was similar to that seen in the U.S. southwest.

"Large, severe fires are normal for this ecosystem. It has burned this way about every 100 to 300 years, for thousands of years," co-author Monica Turner of the University of Wisconsin said in a statement.

"But if the current relationship between climate and large fires holds true, a warming climate will drive more frequent large fires in the Greater Yellowstone Ecosystem in the future."

The forests that drape Yellowstone will have less time to recover in between fires, and faster-growing shrubs and trees like aspen and Douglas fir may replace them. 

"More frequent fires will not be catastrophic to the area -- Yellowstone will not be destroyed -- but they will undoubtedly lead to major shifts in the vegetation," Turner said in a statement.

"It is critical to keep monitoring these forests and study how they respond to future fires."


On the Net: