Harvey Bryant, manager for the project at the Maryland Department of Natural Resources, said his agency "will do whatever is necessary to protect the bat species, since they are endangered."
Final decisions on the tunnel's future are a year away, after completion of an environmental assessment by the University of Maryland's Appalachian Laboratory in Frostburg. The findings will go to DNR and ultimately to the National Park Service, which owns the property as part of the C&O Canal National Historical Park.
The single-track Indigo Tunnel was built in 1904 and served until the Western Maryland Railway abandoned it in 1975. Shored up by wooden cribbing, the 20-foot rock walls are largely exposed. The roof is covered by wooden planking.
There were few bats there when it was abandoned, said Dana Limpert, a DNR ecologist. But it has since become the largest known bat hibernaculum in Maryland. It also appears to be the last major redoubt of the Eastern small-footed myotis.
This tiny bat is listed as endangered in Maryland, rare in West Virginia and threatened in Pennsylvania. Its two largest hibernacula, both in New York state, have been devastated since 2006 by "white nose syndrome." Over two winters, the spreading fungal infection has killed hundreds of thousands of bats in New York and New England.
"We are expecting to lose the Eastern small-footed myotis up in the Northeast," said Aimee Haskew, 29, a faculty research assistant at the Appalachian Lab. "It's possible ... this will be their last large hibernaculum range-wide. Given the conservation status of the species, under state law they warrant protection."
Strolling through the silent, dripping tunnel one night this week, she swept a flashlight beam across solitary bats sleeping on the rock walls. Some ceiling supports have rotted and collapsed, and piles of fallen rock litter the floor.
If the trail goes through, DNR officials said, they would replace the rotted wood; install dim, cool, LED lighting near the floor; and clear fallen rock. But they also would gate both portals so humans could be kept out at times, while still allowing free access to bats.
As a scientist, Haskew insists she is neither for nor against development of the tunnel. But after working with bats for more than four years, she is worried. "They're fascinating creatures, so misunderstood ... such underdogs," she said. "I just don't want to hurt the bats."
