Caves and karst

​Karst is a type of landscape developed on rocks formed mainly of carbonate minerals, which slowly dissolved to form caves, sinkholes and other features. The principal karst rocks in Tasmania are limestone and dolomite. These rocks are common in western Tasmania.

Cave passage, Southwest National Park - Image - Rolan Eberhard

The karst caves and landscapes of Tasmania are considered unique and globally outstanding. This was recognised in the original 1982 listing of western Tasmania as a World Heritage property, and in all subsequent nominations.  The key cave and karst values include:

•    extensive cave systems of high aesthetic quality;
•    human occupation and art sites, some dating back tens of thousands of years;
•    rare or specialised, cave-adapted fauna, such as glow-worms and blind beetles;
•    fossil bones of extinct species including thylacine and giant marsupials;
•    alpine caves and karst developed under glacial climatic conditions.

Available data suggests that about 119,000 ha or 7.5% of the Tasmanian Wilderness World Heritage Area is underlain by karst rocks, including many large and otherwise exceptional karst caves.

There is little data on fire-karst interactions in Tasmania. Karst areas in fire-tolerant vegetation types, such as buttongrass moorland and eucalypt forest, have experienced a history of fire. The effect of this on the karst landforms requires further study.

It can be assumed that underground cave passages are well buffered from the immediate effects of fire. However, near-entrance zones of caves may be affected if the surrounding vegetation is burnt. It is possible that changes to soil and runoff following fire will have some measurable effect on processes deeper underground, during the period while the vegetation regenerates. The scale of possible effect is difficult to evaluate and likely depends on fire frequency and intensity.