Imperiled pikas find haven in lava fields
By Idaho Statesman
May 29, 2007
BOISE, Idaho - Across much of its traditional range, the American pika is waging a struggle for survival, its numbers and habitat diminishing, scientists say, because of rising temperatures perhaps brought on by global climate change.
Yet research shows the mammal, a pint-sized cousin of the rabbit that reaches a top weight of 6 ounces, appears to be thriving in the lava fields of the Craters of the Moon National Monument in eastern Idaho.
Pikas prefer to live in broken rocks in high-elevation mountains, but warming trends have rapidly chased the hypersensitive pika into smaller islands of habitat.
There is another key angle to understanding the pika's plight: Studying its movements and habitat shifts may help scientists measure the effects of climate change on the ecosystems humans and other creatures have come to depend on.
"Pikas may be the early sentinels of biological response to global climate change," Erik Beever, an ecologist with the U.S. Geological Survey, told the Idaho Statesman.
The Earth's warming process happened gradually since the cooler Pleistocene era 10,000 years ago, Beever said.
But in the past two decades, Beever and other scientists have seen pika distribution reduced at rates of years and decades instead of centuries and millennia.
"At half of the locations we've found pikas in the past in the Great Basin, they will be gone in 15-20 years," Beever said.
In Idaho, most of the remaining habitat is in alpine areas like the Sawtooth Mountains and other ranges. But Beever found in the late 1990s that pikas were thriving in Craters of the Moon, the high desert Snake River plain near Arco that is dominated by lava flows, caves and fissures nearly 15,000 years old.
Typically, pikas were found only in talus, the broken rock that lies on a steep mountainside or at the base of a cliff. In these piles of scree, the creatures with thick fur coats take refuge from intolerable, warmer temperatures in the range of 77 to 85 degrees.
"They are just very sensitive to any rise in temperature," said Andrew Smith, a pika expert at Arizona State University.
"Pika habitat is like an upside- down ice cream cone. It just gets smaller as it gets closer to the top."
For centuries, pika populations waxed and waned with the gradual climatic changes, Beever said. They were able to expand their range in cooler times, migrating from rock pile to rock pile down to lower elevations like Craters of the Moon.
But with the pace of climate change quickening, scientists say pika colonies are migrating from lower elevations. Roads, housing developments and even livestock serve as obstacles along the traditional path to higher elevations.
"When they are forced into a different zone, like if they find themselves in an aspen forest, they just wander around," Smith said. "They are lost. Pikas need the rocks to survive."
The Craters of the Moon offers a high desert climate, with average high temperatures during the summer around 80 degrees and average low temperatures in the winter in the teens. Its telltale, flat lava flows connect to the Pioneer Mountains, the southern edge of the northern Rockies.
Historically, the pika's range reached north into British Columbia, the northern edge of their habitat today. Craters of the Moon is among the lowest elevation sites where pikas survive today.
"Pikas remain there because of the physical complexity of the lava structures," Beever said. "Throughout the lava, there are thermal . . . cooler places where pikas can go."
With the decline in pika colonies across the Great Basin, from Idaho to California, the Craters of the Moon could become a critical refuge of the future.
By Idaho Statesman
May 29, 2007
BOISE, Idaho - Across much of its traditional range, the American pika is waging a struggle for survival, its numbers and habitat diminishing, scientists say, because of rising temperatures perhaps brought on by global climate change.
Yet research shows the mammal, a pint-sized cousin of the rabbit that reaches a top weight of 6 ounces, appears to be thriving in the lava fields of the Craters of the Moon National Monument in eastern Idaho.
Pikas prefer to live in broken rocks in high-elevation mountains, but warming trends have rapidly chased the hypersensitive pika into smaller islands of habitat.
There is another key angle to understanding the pika's plight: Studying its movements and habitat shifts may help scientists measure the effects of climate change on the ecosystems humans and other creatures have come to depend on.
"Pikas may be the early sentinels of biological response to global climate change," Erik Beever, an ecologist with the U.S. Geological Survey, told the Idaho Statesman.
The Earth's warming process happened gradually since the cooler Pleistocene era 10,000 years ago, Beever said.
But in the past two decades, Beever and other scientists have seen pika distribution reduced at rates of years and decades instead of centuries and millennia.
"At half of the locations we've found pikas in the past in the Great Basin, they will be gone in 15-20 years," Beever said.
In Idaho, most of the remaining habitat is in alpine areas like the Sawtooth Mountains and other ranges. But Beever found in the late 1990s that pikas were thriving in Craters of the Moon, the high desert Snake River plain near Arco that is dominated by lava flows, caves and fissures nearly 15,000 years old.
Typically, pikas were found only in talus, the broken rock that lies on a steep mountainside or at the base of a cliff. In these piles of scree, the creatures with thick fur coats take refuge from intolerable, warmer temperatures in the range of 77 to 85 degrees.
"They are just very sensitive to any rise in temperature," said Andrew Smith, a pika expert at Arizona State University.
"Pika habitat is like an upside- down ice cream cone. It just gets smaller as it gets closer to the top."
For centuries, pika populations waxed and waned with the gradual climatic changes, Beever said. They were able to expand their range in cooler times, migrating from rock pile to rock pile down to lower elevations like Craters of the Moon.
But with the pace of climate change quickening, scientists say pika colonies are migrating from lower elevations. Roads, housing developments and even livestock serve as obstacles along the traditional path to higher elevations.
"When they are forced into a different zone, like if they find themselves in an aspen forest, they just wander around," Smith said. "They are lost. Pikas need the rocks to survive."
The Craters of the Moon offers a high desert climate, with average high temperatures during the summer around 80 degrees and average low temperatures in the winter in the teens. Its telltale, flat lava flows connect to the Pioneer Mountains, the southern edge of the northern Rockies.
Historically, the pika's range reached north into British Columbia, the northern edge of their habitat today. Craters of the Moon is among the lowest elevation sites where pikas survive today.
"Pikas remain there because of the physical complexity of the lava structures," Beever said. "Throughout the lava, there are thermal . . . cooler places where pikas can go."
With the decline in pika colonies across the Great Basin, from Idaho to California, the Craters of the Moon could become a critical refuge of the future.
