By DAN JOLING - Associated Press
ANCHORAGE, Alaska (AP) — More
shrubs moving onto Arctic tundra because of climate change will have minimal
effect on many of the bird species that breed there, but birds likely will seek
other habitat when the shrubs grow tall, according to a new federal study.
A study by the U.S. Geological
Survey concludes that the size of the shrubs was more critical than the density
in determining whether birds would continue in the habitat.
"Height came out to be the
most indicative of bird habitat selection," said Sarah Thompson, a USGS
research wildlife biologist based in Anchorage and the lead author of the
study.
Multiple studies have shown that
tundra areas are getting more shrubs, Thompson said. Climate warming also is
having effects in the form of longer growing seasons, thawing permafrost and
more frequent and intense wildfires, the authors said.
"All across Alaska, you see
this kind of shrub encroachment into places that previously didn't have shrubs
or didn't have tall or many shrubs," Thompson said.
The researchers over three
summers studied 17 bird species on the Seward Peninsula, which juts 200 miles
into the Bering Sea in western Alaska and includes the city of Nome. The
peninsula, Thompson said, is ideal for study because it includes coastal
habitat and inland settings at a variety of elevations. It's also along the
transition between boreal forest and tundra, Thompson said.
"We can look at all these
different kinds of habitats that might exist in different amounts in the future
and see where birds are, and then we can project forward," she said.
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