DUNLAP, Tenn. -- With his ample midriff, mud-spattered jeans and wire-rim glasses, Julian Lewis does not fit the typical profile of the intrepid explorer. But as he gazed at the craggy cave entrance surrounded by oak and hickory trees, he likened himself to "Star Trek's" swashbuckling Capt. James T. Kirk.
"This is a little bit like Captain Kirk going where nobody's ever been before, from a biological standpoint," said Lewis, an Indiana-based cave expert. "I'm going to unknown biological turf, and I love that, I live for that."
Lewis is in the vanguard of conservationists' ambitious new effort to inventory the living contents of some of the thousands of caves that dominate Tennessee's subterranean landscape. With more than 8,600 known caves, Tennessee has more than any other state, and they provide a home for countless ancient and rare creatures that dwell underground and out of sight.
The caves "are remarkably biodiverse," said David Withers, the state's zoologist. "Very few people know about it. It's not sexy; it doesn't make the papers."
Tennessee's caverns are part of the nation's most elaborate cave network, which extends under Alabama, Georgia and Kentucky, and beyond into Indiana, Virginia and West Virginia.
Most of these caves have never been surveyed for their biodiversity, and some scientific experts estimate that as many as 1,000 species are yet to be discovered. Sheltered until recently from the outside world and with few opportunities to escape, a variety of largely unknown species of cave flora and fauna have evolved out of sight over millions of years.
Many are rarer than ones on the federal government's endangered species list. Biologists use a "Global Rank of Rarity Scale" that specifies whether a species exists in one to five sites in the world, six to 20 sites, 21 to 100 sites and so on. After exploring 22 caves near the Tennessee-Kentucky border last year alone, Lewis discovered 43 species of global significance, including the cave flatworm, the two-clawed spider and four previously unknown species of millipedes.
Withers said Lewis, a private consultant who has devoted more than three decades to cave biology, "can go into any cave and find an organism new to science. . . . It blows me away."
Today, many of these sites are under siege, as the toll of development, logging, sewage disposal and vandalism extends into the underground world. Sedimentation left behind by runoff from deforestation and construction, for example, can clog passageways and streams on which animals such as the threatened Tennessee cave salamander depend.
"Big changes to a cave can wipe {grv}out everything," said Heather Garland, the Nature Conservancy's Tennessee program manager for caves and karst, the term for weathered limestone terrain. "Things grow very slowly, they reproduce very slowly. They survive on stability. They're not very adaptable."
Concerned about development's impact on Tennessee's caves, the Conservancy, a private conservation group, launched the survey that Lewis heads, funded in part by the U.S. Fish and Wildlife Service and other private foundations.
Lewis's year-long study of 50 to 100 caves seeks to determine exactly how many cave beetles, crickets, millipedes and other invertebrates thrive there. Conservancy officials say the expedition will be one of the most comprehensive bio-inventories ever conducted in southeastern caves. In the 1950s and 1960s, Thomas C. Barr Jr. surveyed several hundred Tennessee caves and distributed the samples to taxonomists across the country.
Armed with glass specimen jars filled with isopropyl alcohol as a preservative and processed limburger cheese or spoiled yogurt for bait, Lewis and Conservancy staffers have been burying traps in caves dotted across a stretch of eastern and middle Tennessee.
The surveyors must contend with an array of logistical and physical challenges. Most caves are on private land, and landowners are wary of drawing attention to them because they attract vandals as well as drug addicts looking for a place to get high.
