Tennessee's Caves

What is a Cave?Hidden within middle and easternTennessee's abundant limestonebedrock are a network of secretworlds-cave ecosystems. There aremore than 7,000caves in the state.Beautiful and mysterious, these cavesystems support a highly specializedand diverse group of animals. Cavesare usually thought of as naturalopenings in the ground, large enoughfor a human to enter, and extendingbeyond the zone of light. From thesurface a cave may appear to simplybe a dark hole in the ground. Yet ancautious explorer who is lucky enougto enter a cave may see incrediblesights-gently flowing streams androaring waterfalls, quiet clear pools,gardens of rock and twinkling crystalformations, vertical columns, andcurtains of stone-all hidden within

the darkness. Crucial to the health othese underground ecosystems arethe cedar glades, barrens, forests,streams, and other ecosystems thatlie on the surface.

Tennessee's caves form in atopography called karst, whichincludes sinkholes, sinking streams,subterranean drainage, and springs.The formation of karst topography isdependent on the high solubility ofrocks like limestone and dolomite.Falling rain absorbs carbon dioxidefrom the air and vegetation, formingmild acid that slowly dissolves therock. As the rock dissolves, tinycracks in the rock grow to formunderground openings that overthousands of years can become largerooms and interconnecting passagesextending for miles and having manylevels. As the underground waterflows through small cracks andpassages within the soluble rock, itbecomes saturated with calciumcarbonate and other minerals. Whenthis saturated water reaches a largerpassage or room, the waterevaporates and the dissolved mineralare deposited as beautiful calcite,gypsum, and other mineralformations like hanging stalactites,rounded stalagmites, flower-shaped

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rocks, flowstone, and soda straws.As long as the water continues todrip, the formations will continueto grow and change. Not all cavesare formed or decorated this way.Tectonic caves, for example, areformed by faults and fractures inthe Earth's crust.

Why are Caves Important?Caves house spectacularlybeautiful ecosystems and oftenprovide valuable habitat for manyspecies ofwildlife. Some speciesare so fully adapted to this habitatthat they can live in no otherplace. Caves have also played anintegral role in human history.Early humans found shelter fromthe elements, protection fromenemies and animals, and burial

sites for their dead in caves.Caves were the sights forceremonies that producedunderground "art galleries," such

as the Mud Glyph Cave ineastern Tennessee. Some culturesconsidered caves to be pathways tothe underworld.

During the War of 1812and the CivilWar, caves were valuable sources ofsaltpeter, which was used to makegunpowder. Nitrogen-rich soils androcks found in caves were mined invast quantities to use for saltpeterproduction, and many relics of thishistorical mining activity arepreserved in caves. Hundreds ofartifacts, including ladders, bridges,water troughs, and saltpeter vats,remain as evidence of this era. Todaywe are still drawn to caves because oftheir beauty and mystery and thethrill of exploration.

Habitat and Species DiversityCaves are surprisingly diverseecosystems that provide habitat for avariety of highly specialized wildlife.

While carefully walking,crawling, or even climbingthrough a cave's sandyand muddy passages, itcan befun to imagine whatthe cave looked likethousands of years ago. Ifsteps are taken to protectthese secret worlds, we canensure that our caveecosystems will continueto grow and change foryears to come. Enjoy andtake pride in Tennessee'scave ecosystems! Payattention to signs outsideof caves; never remove acave conservation sign.Always dispose of trashproperly. Never enter asignificant bat cave whenbats are present. Manyimportant bat caves haveseasonal closures. Cavesclosed in the winter toprotect hibernating batsare often open to visitorsin the summer. Preventnonpoint source pollutionand learn more about theconnection betweensurface and undergroundecosystems. Continue tolearn about caveecosystems and the speciesthey support and teachothers about them.

Several factors influence thephysical environment of caves-temperature, humidity, free-flowingwater near the entrance, air flow, andavailable light. Differentcombinations of these factors createdifferent habitats within caves.Hundreds of invertebrates, such asisopods, amphipods, snails,.p1ites,millipedes, and beetles, are adapted tothese specific conditions and arefound nowhere else in the world.While exploring a cave you may belucky enough to see members of threegroups of creatures that depend onthe habitats found in cave ecosystems.Bats, wood rats, and some cavecrickets are known as trogloxenes-cave visitors. These creatures spendonly part of their lives in caves.Troglophiles, or cave lovers, such assome cave spiders, can live out theirlives in caves but can also be found indark, damp places in otherecosystems. Finally, there are thecave dwellers, or troglibites, such asblind cave fishes, crayfishes, cavebeetles, and the Tennessee cavesalamander. They spend their entirelives in caves, having evolved tosurvive in the absence of light, andare often colorless, and eyelessor blind.

Cave systems can be divided intogenerally distinct areas. Uponentering a cave you will firstencounter the cave entrance.Depending on the season, airtemperature in a cave may be warmeror cooler than the outside area. Thecave may feel cold in the summer andwarm in the winter. While hillsidesmay be baking in the summer sun, acave entrance will often remain moistand cool. Some plants, like theendangered American hart's-tongue,have evolved to take advantage ofthis, and in Tennessee they grow onlywithin cool,moist cave entrances.Many terrestrial frogs andsalamanders also take advatltage ofthe coolmoisture found inthis zone.

Following the cave entrance is thetwilight zone, which extends fromthe entrance to the deepest part ofthe cave that is still touched by light.The cave entrance and twilight zoneare the only places wherephotosynthesizing plants can befound. Phoebes and barn owls buildtheir nests in the shelter of thesetwilight zones. Eastern wood ratsbuild their nests here and evenfurther into caves. Because they tendto collect human-made odds and ends,these pale brown mammals have beencalled "pack rats." A wood rat nestmay be decorated with coins, flashbulbs, bits of rope, and cigarettepacks lost or left behind by carelesshumans. Cave salamanders can befound clinging to the rocks and wallsin this zone as well.

Reaching past the twilight zonefurther into the depths of the cave isthe dark zone. Here there is totaldarkness, and the creatures that livehere can survive nowhere else. A fewof these highly specialized creaturesare the blind cave crayfish, Southerncavefish, cave glowworm, and blindcave cricket and the Stateamphibian-the Tennessee cavesalamander. They live on tinyorganisms, such as fungi and bacteria,that grow on decaying organic matterbrought into the cave by streams oron bat guano droppings. The darkzone is the seasonal home ofhibernating bats. EndangeredIndiana bats and gray bats cluster inthe dark quiet reaches of caves fromOctober to May. Female Indiana batsleave the caves to raise their young inthe forest, while gray bats and severalother species of bats depend on caveecosystems year-round.

Rare and Unique Species Depend on

Cave EcosystemsMany of these creatures are rare andunusual; some are endangered orthreatened. The American hart's-

tongue, Indiana bat, and gray bat areall federally listed species. Many

species that are not federally listedare considered endangered orthreatened at the state level. Thestate-listed species in Tennesseeinclude the Eastern big-eared bat,Eastern small-footed bat, Tennesseecave salamander, Southern cavefish,long-headed cave beetle, and searchercave beetle.

Threats to Cave EcosystemsCaves and the karst areas that areoften associated with them haveformed slowly over hundreds ofthousands of years. Caves aredelicate ecosystems that areespecially sensitive to environmentaldegradation. Although seeminglyisolated in their dark undergroundenvironment, their health isdependent on the health of theforests, grasslands, cedar glades, andriver ecosystems that lie above them.Careless human actions can quicklydamage or destroy theseirreplaceable resources. Forexample, activities on the surface cancause contamination of the groundwater that flows into and throughcave systems. Nonpoint sourcepollution from a variety of sources(including pesticides and herbicides);erosion; and storm-water run-off fromagricultural, residential, and urbanareas. Run-off from urban areasoften contains oil, grease, lead, andasbestos. Poorly designed andmaintained septic systems and trashand waste dumped into sinkholes alsocontribute to ground-water pollution.Contaminated ground water is often

considered to be "out of sight, out ofmind." However, caves and karstsare part of the water cycle; therefore,what goes down, must come up.Contaminated water that flows intocaves harms not only the plants andanimals living there but us as well.When water emerges at the surface ata spring or is pumped up from wells,it is not suitable for drinking and canadversely affect us and other plantsand animals, not just those thatlive in caves.

The construction of highwaysand reservoirs and other types ofdevelopment can threaten caveecosystems. If not carefully plannedand constructed, these activities mayalter the water and air flow into andout of caves and cause flooding orthe collapse of cave passagesand chambers.

Cave-dependent bats have suffereddrastic declines because ofthoughtless vandalism. A single ill-timed visit to a hibernation site canresult in the death of thousands ofbats. Humans can wake the bats,causing them to use the preciousenergy they need to make it throughthe winter. A single incident ofhuman disturbance in a bat maternitycave can cause the death of the youngbats because the startled mothers willdrop their pups.

Formations that have taken untoldcenturies to develop into spectacularnatural creations are sometimesbroken off by tourists and rockcollectors who don't realize theirreparable damage they are causing.

What's Being Done?Humans are the problem; fortunately,however, they are also the solution.Increased awareness ofthe value ofcave-dependent species such as batsand the fragility and vulnerability ofother cave resources have led many ofus to a better understanding of theconsequences of our actions.

Many organizations exist today solelyto protect, conserve, explore, andeducate others about the caveecosystems of the world. TheNational Speleological Society wasfounded to advance the study,conservation, exploration, andknowledge of caves. The AmericanCave Conservation Association wasformed for the purpose of protectingkarst lands and caves. They developpublic education programs andprofessional services that addresscaves, karsts, and ground-water

problems and promotes the properstewardship and land-use planning ofcaves and karsts.

The management and recovery of therare and unique species that dependon cave ecosystems sometimesinvolves the construction of gates tocontrol human access. These gatesprevent unauthorized access to cavesbut, if properly designed, do notdisturb the movement of air, water, orbats into and out of caves. Frequentlysigns will be posted outside of cavesalerting visitors to the sensitivecreatures within. Because the surfaceenvironment supplies water andenergy to cave ecosystems,management must include surfaceecosystems as well.

Many cave ecosystems today areprotected by law. The Federal CaveResources Protection Act was signedinto law by Congress in 1988. It wasdesigned to protect and preservecaves on federal land. Tennessee haslegislation in place to protect cavesfrom vandalism, making it illegal toremove or harm cave formations,plants, or animals. It is also illegal totamper with or remove locks, gates,and other structures designed toprevent entrance into a cave.

Seeing is Believing!Tennessee has many trails, parks,and natural areas where you can get aclose-up view ofwild plants andcreatures and their habitats. Usingthe supplemental Tennessee WildlifeViewing Guide, locate and visit a caveor karst ecosystem near you!Consider joining the American CaveConservation Association or a localgrotto of the National SpeleologicalSociety to learn more about caves andhow to safely explore them. Neverenter a cave alone; learn how to safelyexplore cave ecosystems beforeentering one.

Indiana Bat

Tell afriend about theIndiana bat. Pay attentionto signs outside of caves.Dispose of trash properly.Avoid entering significantbat caves. Prevent nonpointsource pollution. Take pridein Tennessee's wildlife!

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StatusThe Indiana bat was listed asendangered on March 11, 1967.

DescriptionThe Indiana bat is a small flyingmammal with a dull, grayish chestnutback and a light pinkish to cinnamonbuffy underside. Its lO-inchwingspansupports a small body that weighsabout as much as two toothbrushes.This small creature could easily fit inyour hand. Indiana bats have smalldelicate feet and tiny sharp teeth.

HabitatThe Indiana bat occurs in theMidwest and Eastern United States.Indiana bats hibernate in cavesduring the winter. They spend therest of the year in forests, resting inhollow trees, under tree bark, and incaves.

Life HistoryIndiana bats breed in early October.They hibernate through the winterand cluster together in tight groupsfor warmth. Each individual bathangs by its feet from the cave ceiling.In late March the hibernating coloniesbreak up, and the females give birthduring June to a single bat. Femalesjoin together to form maternitycolonies,where they raise their youngunder loose bark in old and deadtrees. Young bats are capable offlight within a month of birth.

Role in the EcosystemIndiana bats use sonar to detect andcapture moths and other flyinginsects near riparian and floodplaintreetops. A single bat can eat up to3,000 insects in one night! Bats arethe only major predator of night-flying insects. Cave ecosystemsdepend on bats as a source of organicmatter, as many cave creatures feedon bat guano.

ThreatsThe decline of the Indiana bat hasbeen caused by the commercializationof caves, vandalism, and cavedestruction. When a hibernatingcolony is disturbed, bats use up thestored energy that they need tosurvive the winter. The majority ofthe population winters in only sevencaves, making the species extremelyvulnerable. Indiana bats have alsobeen directly killed by humans. Theuse of insecticides and the destructionof stream-side vegetation can harmbat populations as they feed oninsects. Old and dead trees are oftenremoved for use as fuel, decreasingthe amount of important roostinghabitat.

RecoveryRecovery measures includecontrolling access to caves withproperly designed gates across caveentrances. Some gating has alreadybeen accomplished on public land.The National Speological Society andother caving organizations are taking

steps to prevent the disturbance ofIndiana bat habitat and hibernatingcolonies.

American Hart's-tongue(Asplenium scolopendrium var. americana)

Tell afriend about theAmerican hart's-tongue.Pay attention to signsoutside of caves. Dispose oftrash properly. Rememberto stay on trails to avoidtrampling plants andwildlife. Prevent nonpointsource pollution. Take pridein Tennessee's wild plants!

Reprinted by pennission ofthe Biological Survey,New York State Museum

StatusThe American hart's-tongue waslisted as threatened on July 14,1989.

DescriptionThe American hart's-tongue (afern) has evergreen strap-shapedfronds that arise in a cluster from ashort underground root. Cinnamon-colored scales cover the fronds.Each frond is 5 to 17inches longand 3/4 to 13/4 inches wide.Each frond of this rare plantresembles a long pointed tongue!

HabitatThis species requires deep coolshade, constant high humidity,moist soil, and the presence oflimestone that is high in magnesium.Southern populations are restrictedto limestone pits and sink holes thatoccur in or around caves. Smallnorthern populations exist in Canada,New York, and Michigan. Southernpopulations are found in Alabamaand Tennessee. Of the twopopulations found in Tennessee, a1981survey found that one has beenextirpated and that the othersupports only 17plants, so it is also indanger of extirpation. Anothervariety of American hart's-tongue isfound in Europe.

Life HistoryThe cinnamon-colored scales thatcover the fronds are actually spore-producing reproductive structuresknown as "sporangia." The sporesrequire coolmoist environments todevelop into ferns.

Role in the EcosystemIt is an important component of thebiodiversity of the cave ecosystem.The greater the diversity of species inan ecosystem the healthier theecosystem.

ThreatsThe American hart's-tongue isthreatened by trampling and habitatalteration, including construction,development, timber removal, and

quarrying for limestone. Insectinfestations, which destroy theleaves of shade-producing trees, alsopose a threat. The collectionofwildplants remains a threat to the smallisolated populations of Americanhart's-tongue.

RecoveryManagement and recovery goalsinclude habitat protection and furtherresearch on this rare fern's biologyand life history. The NatureConservancy has leased the land thatcontains the last remaining populationof American hart's-tongue inTennessee in an effort to protect thisrare plant.