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Biodiversity Insights > Cave Fauna of the United States Some of nature's most fascinating creatures are silent sentinels that few have ever seen. These animals live only in cool damp caves where no human footfall disturbs the underground web of life.
Jim Godwin, an aquatic zoologist with the Alabama Natural Heritage Program, has become very familiar with life underground. Godwin is one of a small cadre of cavers whose descents are not quests for adventure, but for discovery of unique forms of life itself. His quarry? The Tennessee cave salamander (Gyrinophilus palleucus), a rare amphibian whose evolutionary path has led it here and only here. In biological lingo, the Tennessee cave salamander is a "cave obligate," a species that lives its entire life underground. Clad in polypropylene and overalls, with helmet light and waterproof map, Godwin has walked, belly-crawled, and even snorkeled his way through some two dozen Alabama caves during six years of surveys for G. palleucus. Godwin and his conservation colleagues have found the salamander in eight of these caves, usually sighting just a few individuals in subterranean streams and pools. But in one large cave that boasts four miles of mapped cave passage, he found an abundant 26 individuals. Based on Godwin's findings, this cave is now considered the mother lode of Tennessee cave salamander habitat.
It's not surprising that Godwin focused his search on Jackson County in northeast Alabama. Jackson County boasts about 1,500 caves—twice as many as any other county in America—and some 24 endemic cave species—animals known from no other place on (or under) Earth. Assessing patterns of cave biodiversity across the United States is the specialty of Prof. David Culver of American University. Culver reports about 1,000 species of cave fauna known in the United States, concentrated in centers of subterranean biodiversity that coincide with areas of limestone bedrock, in which caves form easily. About one-third of these species are known from only a single cave, making them extremely vulnerable to extinction.
Culver's studies have identified northeast Alabama as the premier hotspot for cave animals in the United States (see map), with secondary concentrations in central Kentucky, the southern Appalachians, the Ozarks, Florida, and the Edwards Aquifer in Texas. The cave dwellers of Culver's concern form a bizarre menagerie, from the six-inch salamanders tracked by Godwin, to crayfish, blind fish, spiders, a myriad of insects, and tiny crustaceans like amphipods and isopods. Other than the deep ocean, perhaps no other realm of the Earth's biodiversity is so little-known. And yet, as the discoveries of natural heritage biologists and other researchers make clear, caves are rich in the pieces of nature's puzzle, waiting to be found and understood.
Map adapted by NatureServe from data provided by Prof. David Culver |
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