Aitkin Cave

In a cave, 40, 50, a hundred feet beneath the Earth’s surface, a deep, penetrating silence fills the 54-degree, moist void.

At least that’s the way it is until we human outsiders click off the headlamps and the flashlights, and wait quietly for our sense of sight to release its hold and allow our ears to assume the dominant role in sensory input. As that happens, we begin hearing the drips of water, the occasional squeak of a bat, the delicate sounds of the life of the cave.

And in those soft sounds live the exclamation points that gently highlight the importance of The Nature Conservancy’s new effort to catalog the caves of the Central Appalachians and set conservation priorities among them.

Staff throughout the region have been developing a region-wide database of known cave systems, drawing on existing sources such as cave society and natural heritage lists, and creating a process for defining cave systems in the region. Combined with existing information about the rare species that inhabit caves, the congregated knowledge will allow the Conservancy to set cave conservation priorities for the region.

“Each of the states in the region has some cave work that they’ve done, but none of us have worked systematically across the region,” explains Nels Johnson, director of conservation programs for the Conservancy in Pennsylvania.

In Pennsylvania, for example, the Conservancy has conserved the half-mile of Aitkin Cave and the surrounding 43 surface acres in Mifflin County as the Richard O. Rowlands Preserve, made possible by and named for the longtime conservationist from Scotland who later lived in State College. It has also conserved Hartman Cave in the Cherry Valley Preserve in Monroe County.

“Aitkin Cave is a good example of the kind of cave we’re interested in conserving, because of all the bat species in there,” says Johnson. The cave serves as a winter home for the extremely rare Indiana bat, the rare small-footed bat, the rare Keens bat, the little brown bat and the big brown bat.

The most recent hibernation census of the bats in the cave by biologists from the Pennsylvania Game Commission, in February 2006, documented the return of Indiana bats after an absence of nearly a decade and a doubling of the number of little browns to about 3,500.

That’s an extremely strong showing, according to Conservancy Fire Specialist and Land Steward George Gress, particularly considering that “bats are one of those species that take a long time for the population to increase, because they only have one pup per year.”

Pointing to the massive population decline that the insect-eating, plant pollinating bats in general are thought to have experienced over the past century, Johnson praised the “incredibly important ecosystem service that’s being provided by that cave.”

In addition, a rare cave isopod—a shrimplike creature—is found in the underground streams of the cave.

“We have an interest in seeing the caves protected and not vandalized,” says Johnson. “Many of these caves are sensitive to temperature, humidity and bacteria. In some cases, even a few people a year can have an impact,” even if those limited visitors do no intentional vandalism. (The two Conservancy caves in Pennsylvania are open only under special arrangement during the nonhibernation part of the year, May through August.) “And we do know that caves get closed by landowners over liability issues,” he notes.

In the Central Appalachians, explains Dr. Scott Bearer, forest ecologist for the Conservancy in Pennsylvania, with experience researching bats in the state, the conversion of agricultural areas to residential development often leads to bulldozing or dynamiting cave entrances by the new owners.

“If you close it at the wrong time [of year], you could kill an entire colony of bats,” he says. In addition, says Johnson, “caves are usually formed by water that runs through the limestone formation,” meaning that such “wet solution caves” have a critical and direct connection to shallow groundwater and can be deeply impacted by water pollution or diversion. Each cave faces specific threats determined by its physical circumstances.

A remote cave distant from a roadway generally won’t experience much vandalism. A cave surrounded by agriculture might face issues of water quality.

No one is certain how many caves face each of the possible threats, because “the caves that have been inventoried are a small fraction of what’s out there,” says Johnson.

Beyond working with willing landowners to secure conservation purchases and easements following the initial prioritization of the caves, the accompanying education and outreach efforts will pay dividends with private owners as well.

“If most landowners knew more about the value of their cave and the benefits it generates, they would do the right thing” and choose alternatives to complete closure, says Johnson.

For those landowners, for the bats and other cave-dwelling creatures, for the public that draws benefits from caves and their inhabitants, Bearer says, setting the cave priorities for the region will help the Conservancy to see “where we should be focusing our work.”

Caves Are Home to the World’s Rarest Species Bats probably are the creatures that first spring to mind on those rare occasions when one thinks about creatures that live in caves.

Mirroring lay society, most scientific inquiry into cave creatures also has focused on the vertebrate species—the bats and the wood rats— with much less attention paid to the invertebrates—the isopods and the amphipods.

Further complicating the situation, nonflying, cave-dwelling species are often found in just a single cave or cave system, because “while the caves may be connected locally, they’re not connected regionally,” notes Johnson.

And experts in those lesser-known species, even in their basic identification, can be as rare as the species themselves.

“There are many species waiting to be identified with very few experts in their identification,” says Johnson. For example, the only man who can precisely identify one group of isopods (crustaceans), is believed to be a 78-year-old scientist in Japan.

Reprinted with permission from The Nature Conservancy’s Penn’s Woods newsletter.

3/14/2008