Caves as Ecosystems

While caves present unique obstacles to their inhabitants, a plethora of life can be found inside not only Mammoth Cave, but also the hundreds of smaller caves located within the park boundaries.These animals found inside caves can be classified into three categories:

Trogloxenes - in Greek, troglos means cave, and xenos means guest. Trogloxenes come and go from caves, they typically use cave habitats as hibernation, nesting, or birthing spots. They are not adapted to spending long amounts of time in the cave, nor will they spend their entire lives in the darkness. Bats and moths are trogloxenes.

Troglophiles - troglos meaning cave, and phileo refers to love. These organisms prefer to live inside a cave but may leave the cave to search for food, a cleaner habitat, or to mate. Crustaceans like crayfish are an example of a troglophile, they can live their entire lives inside or outside a cave system.

Troglobites - troglos for cave, and bios for life. Troglobites spend their entire life cycle in caves. They only live in underground habitats, adapted to survive in total darkness. Troglobites have depigmentation, a decrease or total loss of eyesight, a slow metabolism, and are able to efficiently digest and consume food. Troglobites cannot survive on the surface nor travel between cave systems, typically they are endemic to a single cave or a single cave system. The endangered Kentucky cave shrimp is an example of a troglobite.

 

A cave crayfish moves through a shallow pool of water in the cave.

NPS Photo/ Anya Gupta

Cave Aquatic Ecosystem

As rainwater percolates through the soil, it washes dissolved organic matter into cave streams, where microscopic organisms feast on the organic matter. Several kinds of tiny invertebrates, such as isopods, snails, and cave shrimp, graze on the microbes growing on rocks in the stream. Some of these grazers are prey for cave crayfish and fish. Cave fish are the top predators in the cave aquatic ecosystem.

In the lowest parts of cave streams, near spring outlets along the Green River, there are times when water from the river back-floods into the cave. When that happens, all manner of things can get washed into the cave, including fish living in surface streams. Surface fish that do not get washed back out, perish in the cave and sink to the bottom where they can be eaten by crayfish.

The back-flooding into low level cave streams provides nutrients as well, and cave-dwelling bats benefit from insects that gather in the river passages. These river passages provide bats with a food source and water to drink. This is especially important for lactating bats with pups back at the roost.

 

Cave cricket walking on gypsum in Turner Avenue of Mammoth Cave.

NPS Photo

Terrestrial Cave Ecosystem

Some cave inhabitants, such as bats, cave crickets, and woodrats go out at night to feed in forests and grasslands, drink from the rivers or wetlands, and then return to the cave to roost or nest in relative safety. The eventual guano and droppings are the food base for a surprising number of cave-adapted creatures.

Cave crickets also lay their eggs in sandy, moderately dry cave passages where a species of blind cave beetles live. These beetles are very good at finding the cricket eggs and preying upon them as a food source, adding another link in the cave system food web.

Larger animals may come and go from caves as well. Raccoons have been known to enter bat roosts and prey upon hibernating bats; vultures and other bird species have been spotted using rock ledges just within cave entrances to nest with their broods. Commuting cave crickets, traveling in and out of caves, run a gauntlet of predatory cave orb weaver spiders and cave salamanders, the latter of which can be found in the forest too.

 

Hydrological Activity

 

Restoring Cave Ecosystems

Crystal Lake Cleanup

 

Restoring Cave Ecosystems

Mammoth Cave Lint Bunnies