The preservation is also fragile, however.

It depends on the conditions remaining stable.

Changes in the cave’s air circulation — caused by new entrances, by the removal of old ones, by changes in the landscape above — can alter the humidity and temperature that preserve the ancient evidence.

Tourist use of cave passages generates heat and moisture from human bodies, and these effects have to be managed to prevent damage to both the archaeological and geological record.

The NPS management of Mammoth Cave reflects this fragility.