Ecosystems at Risk: Limestone caves
7b. Human Impacts: Caves

Increased foot traffic near entrances may accelerate the in washing of fine sediments which covers former floor habitats. Lighting systems in tourist caves are an artificial source of energy which encourages the growth of algae which will impact on the food chain introducing more food to particular points in the cave causing a redistribution of animals. A single person in a cave releases heat at a rate of between 82 and 116 watts. At Remouchamps Cave in Belgium a single party of 87 tourists raised cave air temperature by 1.50C during a five minute visit. This rise in temperature creates a large change in humidity since warm air can hold more water vapour than cold hence the relative humidity falls dramatically, drying the cave atmosphere. Even the exhaling of carbon dioxide by tourists can have a serious effect. At Yarrangobilly Caves the temperature of Jillabenan Cave is closely monitored because it is a small cave with limited air flow. When the temperature rises by more than 0.5 0C the cave is closed to public access.
Toilet block at Yarrangobilly Caves. Careful disposal of sewage is required due to the importance of groundwater to cave systems. Cave entrances may be blocked by doors or grids to protect them from vandalism. Unfortunately this may also change the air flow or access to animals which use the caves. Passages may be widened for easier access thus changing air flow.
The energy base of the cave ecosystem can be dramatically changed by people. Flakes of skin and hair we are always shedding or crumbs of food we take in may change the food chain in caves which have regular visitors. The original floor ecosystem relying on bat guano will no longer have an energy base for its food web if the bats relocate.
 
  management  
Many cave areas have been mined for limestone either destroying the whole cave system or opening it up to air movement and other disturbance. Lime has many uses in today's society including cement, glass and water purification. This limestone mine near Kempsey was closed because of the impact on mining to the caves and resident bat colonies.