Story and photos by Benjamin Zack • Standard-Examiner staff
Change happens slowly in Logan Cave.
Sunlight reaches only a few feet into the entrance of the nearly mile-long tunnel. The water that has smoothed and carved out the limestone passages flows for just part of the year, when snow is melting in the Bear River Mountains.
Even the temperature in the cave is slow to change from month to month. The climate inside is much cooler than the surrounding canyon during the summer, and warmer in the winter.
On a snowy February day, two biologists and an archaeologist climbed a half-frozen waterfall to check on the latest change to the cave.
More than 20 years ago, Logan Cave was open and easily accessible to anyone who made the relatively easy trip up Logan Canyon. The worst of the visitors left graffiti, broke off rock formations and lit fires inside the cave. Even the presence of casual cavers could disturb the bats that used the cave to hibernate and raise their young.
In 1995, the U.S. Forest Service installed a gate at the towering mouth of the cave to protect the bat population and the greater cave ecosystem. Since that time, access to the cave has been closed off to the general public.
Adam Brewerton is one of the the few people who enter the cave nowadays.
Brewerton is a wildlife conservation biologist with the Utah Division of Wildlife Resources. During the winter, Brewerton and other biologists enter the cave to count the number of hibernating Townsend’s big-eared bats — the most common bat species in Logan Cave.
This year, the bat surveyors counted 385 Townsend’s.
“That number, around 400, has been constant the last couple of seasons,” Brewerton said. “In 1995, right before they put the gate up, the count was 19. One. Nine.”
“The cave closure is definitely working from the perspective of conserving the bat population,” Brewerton added.
Logan Cave features one of the largest known populations of Townsend’s big-eared bats in the state. Most colonies are made up of only five to 20 bats, with a few reaching populations of 50-80, according to Brewerton. Scientists know of only one other cave near Cedar City with populations like those found in Logan.
Townsend’s big-eared bats are medium-size brown and gray bats with jackrabbit-like ears that stretch out more than an inch on a body that measures around 4 inches. The bug-eating mammal can be found in deserts and pine forests around the western United States and Mexico.
One of the things that makes Logan Cave such an attractive destination for the bat is that there are two separate tunnels at the cave entrance. The main entrance provides a cool environment perfect for hibernation, while a second smaller passage directly above the main entrance is warmer, drier and an ideal environment for raising bat pups.
However, after two decades, some people have figured out ways to break through the metal fence at the entrance to the cave. The reason behind Brewerton’s latest trip to the cave, along with Forest Service wildlife biologist Masako Wright and archaeologist Rachelle Handley, was to work on plans for new gates.
Wright says she hopes to have the new gate in place in a year or two.
In addition to their work to protect the bats in Logan Cave, Utah wildlife biologists still have a lot questions about local bat populations.
“There’s a lot of big data gaps,” said Wright. “We try to figure out where they are and what species we have.”
Wright and her colleagues are also keeping an eye out for white-nose syndrome, a disease that is wiping out tens of millions of bats on the East Coast. So far, the fast-moving disease hasn’t reached Utah or neighboring states, but that doesn’t mean scientists aren’t concerned. On the latest survey in Logan Cave, Brewerton and Wright swabbed several bats and sent samples to a lab to look for signs of white-nose syndrome.
“If we detect it soon enough, we can hopefully contain it and keep it from spreading further,” said Brewerton.
For now, scientists plan to make one more trip to the cave to further examine gate locations. After that, they’ll put away the key for several months as the bats wake up and begin to raise their young.