Post by L Roebuck on May 12, 2006 9:28:22 GMT -5
Caves keep growing despite long drought
Long-term effects on Kartchner uncertain
By Dan Sorenson
arizona daily star
Tucson, Arizona | Published: 05.12.2006
The air is so soggy in Kartchner Caverns' Throne Room that 71 degrees feels absolutely stifling.
But Southern Arizona's famous "living caves," limestone caverns with features that are still growing, apparently aren't immune from Southern Arizona's drought. Scientists are concerned that the caves might not be moist enough, that they might be getting too hot and drying out.
As temperatures go up, as they have by three to five degrees Fahrenheit since the caves were developed for tourism, the air can hold more moisture but the relative humidity may go down, said Rick Toomey, the state's former cave scientist. Toomey left the Parks Department last summer to take a job as director of the Mammoth Cave International Center for Science and Learning in Kentucky.
Toomey and Kartchner managers and scientists know the world is watching to see how they do in preserving the $27 million "crown jewel" of the state parks system.
Park Ranger Susan Stucker, a tour guide who has been at Kartchner since its official opening in 1999, said some of the caves' features — soda straws, towering stalagmites, hanging stalactites, wildly colored translucent ribbons — appear drier and don't glisten the way they used to in the caverns' dim lights.
And Stucker said some features don't look as vivid as they did when they were wetter. She said someone who isn't in the caves all the time, like she is, may not notice things like slower dripping from the soda straws — the thin, hollow tubes that hang from the ceiling.
When the lights are briefly turned on for tours, she said the Kubla Kahn, a huge floor-to-ceiling formation, may not be as shiny as it was in wetter times.
But changes can be short-term, too. Formations become noticeably wetter two to three days after a significant rainfall in the park, Stucker said.
Long-term trends are the real concern. Park staffers monitor many points in Kartchner's chambers, even far corners the public never visits. Staffers only get to some of them once a year, said Park Ranger Eric Cook of the State Parks Department's Cave Unit.
Temperatures have risen and humidity is down since the first measurements were taken and development of the caverns was started in the 1990s.
But are the changes due to the climate outside, the construction that was necessary to make the caves a public attraction, or the public that has flocked to the cave since 1999?
"That's something we're trying to separate," said Cook. "There certainly is an effect from the drought. Temperatures have been going up and humidity has been going down in (nearby) caves that don't have regular visitors.
"But with Kartchner," he said, "there is energy input from lights and humans walking through."
Cook and Toomey believe most of the changes in humidity and temperature came as a result of the development of the cave in the late 1990s, when the largest changes in temperature and humidity occurred. Still, they said, throughout that time temperatures outside were rising slightly and annual rainfall was below normal.
The temperature and humidity have actually stabilized in the last two years, Toomey said.
From 2003 on, the mean temperature in the Throne Room has been stable at 71.5 degrees . It was 67.5 before development work, Toomey said.
Meanwhile, he said, the humidity has stopped dropping. And, because they have no way of knowing what "normal" is (their baseline humidity figures were taken during a wet period) Toomey said they don't know what they should expect.
Life-sustaining guano
Coal mines have canaries. Caves have bats. And so far, Kartchner's migrating myotis cave bats are happy, said park Ranger Ginger Nolan and bat consultant Debbie Buecher, suggesting that Kartchner Caverns are healthy — at least healthy enough for the bats and the creatures that feed off their droppings.
"Absolutely, if you don't have the guano in the cave, everything else will die," Arizona State Parks spokeswoman Ellen Bilbrey said. "The circle of life from the guano — if you lose that, the whole ecosystem will die."
The cave known as the Big Room closes to human visitors in mid-April when the myotis bats come to roost. The mothers give birth to a single pup in a breeding season, and the Big Room remains closed until the bats leave again in the fall.
Their excrement, guano, is fed on by a host of tiny creatures that feed on the mold and fungi that grow on the guano. Then other creatures, including crickets, feed on them.
Buecher said radiocarbon dating of guano in Kartchner shows that bats have been coming here for at least 40,000 years.
So far this year, about 50 to 75 of the cave myotis bats have been seen entering and exiting through the sinkhole entrance of Kartchner's Big Room.
The cave myotis aren't endangered, Bilbrey said, but, by nature, a "living cave" always is fragile. Kartchner is referred to as a living cave because the formations inside it are still growing, a rarity in so-called "show caves," caves open to the public.
Not far from the sealed human entrances and the tiny natural entrance to the caverns, a group of freetail bats has shown up to hang out under a bridge that connects the Kartchner Caverns State Park visitor center to the caves.
It's too early to tell how well the breeding season is going, the park's bat experts said. Things are more or less on schedule, said Buecher, who has helped the state measure the bat populations.
The idea is that more bats should leave than arrive. She said there's a 40 percent mortality rate in the bats' first year of life and the low birth rate keeps the population from growing quickly.
Reservation agent Kimberly Lawrence says Kartchner continues to be a hit with Arizonans. This week, she says, Mother's Day and the University of Arizona graduation are selling out tours.
On StarNet: Take a virtual tour of the cave at azstarnet.com/multimedia
Contact reporter Dan Sorenson at 573-4185 or dsorenson@azstarnet.com.
Kartchner Caverns State Park
Long-term effects on Kartchner uncertain
By Dan Sorenson
arizona daily star
Tucson, Arizona | Published: 05.12.2006
The air is so soggy in Kartchner Caverns' Throne Room that 71 degrees feels absolutely stifling.
But Southern Arizona's famous "living caves," limestone caverns with features that are still growing, apparently aren't immune from Southern Arizona's drought. Scientists are concerned that the caves might not be moist enough, that they might be getting too hot and drying out.
As temperatures go up, as they have by three to five degrees Fahrenheit since the caves were developed for tourism, the air can hold more moisture but the relative humidity may go down, said Rick Toomey, the state's former cave scientist. Toomey left the Parks Department last summer to take a job as director of the Mammoth Cave International Center for Science and Learning in Kentucky.
Toomey and Kartchner managers and scientists know the world is watching to see how they do in preserving the $27 million "crown jewel" of the state parks system.
Park Ranger Susan Stucker, a tour guide who has been at Kartchner since its official opening in 1999, said some of the caves' features — soda straws, towering stalagmites, hanging stalactites, wildly colored translucent ribbons — appear drier and don't glisten the way they used to in the caverns' dim lights.
And Stucker said some features don't look as vivid as they did when they were wetter. She said someone who isn't in the caves all the time, like she is, may not notice things like slower dripping from the soda straws — the thin, hollow tubes that hang from the ceiling.
When the lights are briefly turned on for tours, she said the Kubla Kahn, a huge floor-to-ceiling formation, may not be as shiny as it was in wetter times.
But changes can be short-term, too. Formations become noticeably wetter two to three days after a significant rainfall in the park, Stucker said.
Long-term trends are the real concern. Park staffers monitor many points in Kartchner's chambers, even far corners the public never visits. Staffers only get to some of them once a year, said Park Ranger Eric Cook of the State Parks Department's Cave Unit.
Temperatures have risen and humidity is down since the first measurements were taken and development of the caverns was started in the 1990s.
But are the changes due to the climate outside, the construction that was necessary to make the caves a public attraction, or the public that has flocked to the cave since 1999?
"That's something we're trying to separate," said Cook. "There certainly is an effect from the drought. Temperatures have been going up and humidity has been going down in (nearby) caves that don't have regular visitors.
"But with Kartchner," he said, "there is energy input from lights and humans walking through."
Cook and Toomey believe most of the changes in humidity and temperature came as a result of the development of the cave in the late 1990s, when the largest changes in temperature and humidity occurred. Still, they said, throughout that time temperatures outside were rising slightly and annual rainfall was below normal.
The temperature and humidity have actually stabilized in the last two years, Toomey said.
From 2003 on, the mean temperature in the Throne Room has been stable at 71.5 degrees . It was 67.5 before development work, Toomey said.
Meanwhile, he said, the humidity has stopped dropping. And, because they have no way of knowing what "normal" is (their baseline humidity figures were taken during a wet period) Toomey said they don't know what they should expect.
Life-sustaining guano
Coal mines have canaries. Caves have bats. And so far, Kartchner's migrating myotis cave bats are happy, said park Ranger Ginger Nolan and bat consultant Debbie Buecher, suggesting that Kartchner Caverns are healthy — at least healthy enough for the bats and the creatures that feed off their droppings.
"Absolutely, if you don't have the guano in the cave, everything else will die," Arizona State Parks spokeswoman Ellen Bilbrey said. "The circle of life from the guano — if you lose that, the whole ecosystem will die."
The cave known as the Big Room closes to human visitors in mid-April when the myotis bats come to roost. The mothers give birth to a single pup in a breeding season, and the Big Room remains closed until the bats leave again in the fall.
Their excrement, guano, is fed on by a host of tiny creatures that feed on the mold and fungi that grow on the guano. Then other creatures, including crickets, feed on them.
Buecher said radiocarbon dating of guano in Kartchner shows that bats have been coming here for at least 40,000 years.
So far this year, about 50 to 75 of the cave myotis bats have been seen entering and exiting through the sinkhole entrance of Kartchner's Big Room.
The cave myotis aren't endangered, Bilbrey said, but, by nature, a "living cave" always is fragile. Kartchner is referred to as a living cave because the formations inside it are still growing, a rarity in so-called "show caves," caves open to the public.
Not far from the sealed human entrances and the tiny natural entrance to the caverns, a group of freetail bats has shown up to hang out under a bridge that connects the Kartchner Caverns State Park visitor center to the caves.
It's too early to tell how well the breeding season is going, the park's bat experts said. Things are more or less on schedule, said Buecher, who has helped the state measure the bat populations.
The idea is that more bats should leave than arrive. She said there's a 40 percent mortality rate in the bats' first year of life and the low birth rate keeps the population from growing quickly.
Reservation agent Kimberly Lawrence says Kartchner continues to be a hit with Arizonans. This week, she says, Mother's Day and the University of Arizona graduation are selling out tours.
On StarNet: Take a virtual tour of the cave at azstarnet.com/multimedia
Contact reporter Dan Sorenson at 573-4185 or dsorenson@azstarnet.com.
Kartchner Caverns State Park