keeps a few caves closed permanently, requires cave registration and decontamination
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By Bob Berwyn
FRISCO — The White River National Forest is well-known for its many ski areas and stunning high-elevation wilderness areas, but the forest is also a Rocky Mountain stronghold for bats. And with a deadly disease poised to move into the region, resource managers are taking steps to try and protect the flying mammals with a new cave access policy.
Based on a regional study completed a few weeks ago, WRNF supervisor Scott Fitzwilliams has decided to keep several caves with biologically significant populations closed all year, and other caves may be closed seasonally. Year-round closures are to be enacted on ranger districts if white-nose syndrome is documented within 250 miles. The regional policy and supporting documents are online at this Forest Service website.
Forest Service officials said only a handful of about 100 known caves are important to manage for bat populations with regard to white nose syndrome. The new policy is aimed at balancing traditional recreational and scientific access with protection of sensitive bat species.
The White River National Forest has the highest number of maternity and swarming sites of any management unit in the region, but smaller numbers of caves used for hibernation, when the bats seem most susceptible to the fungal disease. It’s not clear whether swarming and maternity caves play a role in the transmission of the disease.
“This is really a serious biological concern, it’s a brand new disease, and it’s new management for us,” said White River National Forest biologist Wendy Maguire. “We want to make sure people really understand what’s going on,” Maguire said.
“We are concerned that at some point it may show up here … And we hope to prevent the spread of the fungus by people. That’s why we are adopting some of these optional measures up front,” Maguire said, describing the new plan.
Cave visitors must educate themselves about the issue and respect the new rules to protect potentially susceptible bat populations in Colorado, and they can help biologists detect signs of the disease by reporting unusual bat behavior, including unusual daytime flights during hibernation season.
Decontamination procedures will be required for all caves on the forest to try and prevent white-nose syndrome from spreading to bat populations on the White River National Forest, and caving gear and clothing from states where the disease is suspected or confirmed is banned. The Forest Service also hopes to gain a greater understanding of cave visitation with a registration system.
For the past two years, almost all caves and abandoned mines were completely closed to entry, as various agencies scrambled in the onslaught of the disease, which has all but wiped out major bat populations, killing 5.5 million in just five years, starting in the northeast in 2007 and spreading as far south and west as Oklahoma.
It’s that westward spread that worries Forest Service biologists. Some bats fly hundreds of miles in migrations. It’s very likely that the disease is being transmitted by bats from cave to cave. It’s suspected that that the disease was introduced to the U.S. from Europe by a cave visitor, but the role of humans in the subsequent spread is not clear.
Some of the biological models suggest that white-nose syndrome will eventually spread to the Rockies, said regional Forest Service biologist Rick Truex. Other research shows that Colorado caves (and those in the Black Hills region) have conditions suitable for the fungus that infects and kills nearly all exposed bats.
“Whether or not it can be brought in by bats or by humans we simply don’t know, but there are things we can do, reducing the amount of disturbance during the winter and breeding season,” Truex said.
The Rocky Mountain region is home to the same species of bats that have already been devastated by the disease, including little brown and big brown bats.
“We hare several species that are hibernating bats … They have been hit pretty hard,” Truex said. “On the other hand, a lot of the small-bodied bats that we have in the Myotis genus have not yet been exposed to the fungus,” he added.
“The disease running its course is likely, but hopefully we can lessen its impact,” he concluded.
Maguire said the WRNF has decent baseline information from monitoring.
“We’ve been plucking away, and when we find a cave that’s used by bats, we’ve picked up our monitoring game. There’s a recognition that cave resources are quite unique, that the cave ecosystems quite unique,” she said.