CONSERVATION OF CAVES AND KARST IN AUSTRALIA FROM A GEOLOGICAL PERSPECTIVE
ABSTRACT
Various programs in Victoria over the past 20 years have expounded the value of caves and karst. The geological and geomorphological values of caves have had a higher valuation in these programs than previously, when cultural/aesthetic/biological values of caves were more emphasised. The main principles on which conservation can be based from an earth science perspective will be outlined with some implications for management.
Speleologists and cave managers are always concerned with the protection, conservation and interpretation of cave and karst landscapes. However, there is increasing concern as to the reasons sometimes given for protection/conservation/interpretation, etc. Caves and their related landforms are a geological/geomorphological feature. They may house biological specimens (both live and dead) but they are geological/geomorphological features. As such features they are not a static feature but a feature which is undergoing change - albeit slowly. What is of concern is that increasingly we are moving away from caves and karst being a total landscape and concentrating of fauna, flora and caves merely as a container for them. A particular example occured in Victoria where a National Park Plan was so concerned about fauna especially bats, and ferns in cave entrances that it hardly gave a mention of the total karst landscape. The plan was therefore seriously flawed as a result.
The processes involved in caves and karst are geological and geomorphological:
- solution - rock is chemically dissolved
- volcanism - concentrations of hot gases or liquid rock reach the surface
- cavernous weathering - when the growth of salts in percolating water within the rocks is concentrated leading to mechanical disintegration of the rock surface and enlargement of hollows
- boulder weathering - weathering and then erosion along joints leading to cavities (this relates to solution but is not identical)
- piping - removal of unconsolidated elastic materials (i.e. loose particles, e.g. sand, alluvium, colluvium) are mobilised and removed - not in solution but in suspension of dispersible material. This is especially important in clays and the holes are rarely stable
- wave action - mechanical
The balance between these processes and others determines the landscape. In karst solution is usually dominant but in volcanic landscapes it is not. The decision between what is true karst and what is pseudokarst is directly related to these processes.
Caves and karst features are important aspects of the total landscape and geology of an area. They house aesthetic, heritage, conservation, scientific, education and recreation values. Although conservation is often thought of with respect to plants and animals the physical features of the landscape itself may be at least as important and may be more important.
Over the past 15 years various agencies have been involved in documenting and assessing cave and karst sites with conservation and management objectives. On a national level this has included the National Estate listings through the Heritage Commission of the Federal Government. National Estate funding has been and is available to various state bodies to do this. Similarly, the Geological Society of Australia has a Standing Committee on Geological Monuments and the various state divisions have geological conservation groups. These have often benefited from the National Estate grants in being able to fund the documenting and assessing the significance of sites of scientific and/or heritage interest. Similarly, state government departments have undertaken documentation and assessment programs of sites. For example, Victoria during the 1970s conducted an ecological studies program of sites of scientific significance which included geological and geomorphological sites as well as botanical and zoological sites. Both these types of documentation had karst sites listed. Those workers who collaborated closely with the caving clubs were generally more accurate than those that did not but all the reports were useful. Also, the then Victorian Department of Conservation, Forests and Lands specifically commissioned a study in 1985 to establish a detailed data base for caves and karst for the whole state for management purposes.
These studies are important because their methodologies emphasise that the reasons for high significance and high conservation value for karst sites do not solely rest on whether there is important biological material associated, e.g. bat sites, or similarly on whether there a number of pretty stalactites and stalagmites. In fact, cave resources are important for seven major reasons (Davey and White 1976):
- functioning ecosystems
- aesthetic appreciation
- natural systems of landscapes
- type localities
- natural processes
- cultural features/landscapes
- recreation opportunities
In many cases these values can overlap. In this paper concentration is on the geological/geomorphological values of the karst system rather than the other values but this is not to limit the other values but to give some understanding how and why karst features can have these geological values.
Similarly, the directly geological/geomorphological processes in the natural systems of landscapes, type localities and localities showing natural processes can be defined in more detail using the following system:
A: Geological
- type locality of a geological formation - e.g. Buchan Caves Reserve: type locality for Buchan Caves limestone
- contact between geological formations - e.g. Pyramids area, Buchan: contact between Snowy River volcanics and Buchan Caves limestone
- extensive outcrop - e.g. East Buchan
- display of geological structure - e.g. East Buchan Thrust Fault
- fossil deposits - e.g. APM Quarry Rocky Camp
- outcrops with mineral deposits - e.g. W Tree Opal deposits
B: Geomorphological
- sites which clearly show the relationship between lithology, structure and landform - e.g. Anticline Cave, Murrindal
- sites which display the action of geomorphological processes - e.g. terraces of the Buchan River and their relationship to the stream caves
- sites which are representative of the major landforms - e.g. Buchan karst areas are an excellent example of surface and underground karst development in Eastern Victoria (Rosengren and McRae Williams 1980)
Parallel to this is a value judgement on significance. If a feature is significant what does this mean? To whom is it important? A dictionary definition of significance includes two aspects: having importance or consequence and having meaning. As a consequence to this significance in this context has both a representative and an outstanding component. This is then whether the site is arguably an interesting representative of its kind, representation being based on type of cave or karst feature and related to a comprehensive classification of caves and karst, or whether it is based on key characteristics of caves and karst. Likewise whether the site is arguably an outstanding feature in some way (Davey and White 1986).
To show an adequate coverage of significance for sites a series of places showing all the possibilities for both A and B would need to be described. Davey and White (1986) further list fifteen grounds as to the reasons why the site is significant. Included with this must be grounds for site evaluation as what makes a site representative and/or outstanding. These include whether the site:
- has contributed substantially to development of explanations about a wider class of sites is the location of important research investigations
- contains evidence with potential for understanding the past (e.g. speleothems, sediments, palaeontological or archeological deposits, cultural relics)
- has important associations with prehistoric or historic human activities, especially if connected with important events, personalities or developments in the history of the region or of cave science
- is the type locality for any species
- is the habitat of an endemic species
- is habitat for any troglobitic species
- is the breeding locality (maternity site) for any species, or is important to any species for acclimatisation, over-wintering, staging or roosting
- is aesthetically impressive or of high visual or other sensory quality
- contains unusual recreation opportunities
- has potential for non-destructive use which will contribute to the local and regional economy and employment
- is one of the few remaining or best preserved of its class
- is part of a related complex of sites which collectively meet one or more of the other criteria above (Davey and White 1986)
Part of the task of understanding significance is also to identify a level of significance. A useful scale is:
- international - worldwide
- national - a sovereign state
- statewide - a major juridical division within a sovereign state
- regional - a natural physiographic and bioclimatic region
- local - discrete places or areas within a region
Usually these criteria are only useful for sites that are well known. The ongoing need to update such criteria with respect to improved knowledge of the resource is important. Too often the knowledge base is not updated in the light of new discoveries or better knowledge of the resource.
Much of what is outlined in this paper is not new or revolutionary. Davey (1984) outlined much of this and his work has been extensively used by speleologists when looking at karst values. Managers however, have been more concerned with the biological or archaeological aspects of cave management. In ignoring the work on geological and geomorphological values in this way they have done a disservice to their management. A greater understanding of these values will only enhance their management.
The threats to the main estate are generally well known. It is just as serious to obliterate a geological type locality as a biological one and that obliteration can occur by planting trees on such a site or the grading of a steep slope or cliff. The addition of geological/geomorphological values into a management strategy is to improve management.
In conclusion, the significance of a site and its values are important for geological as well as aesthetic, biological and recreational reasons. Managers need to include this in their management strategies and the threats to the karst estate can be on these values as well as the others.
REFERENCES
Davey, A.G., ed. 1984 Evaluation criteria for the cave and karst heritage of Australia. Report of the Australian Speleological Federation "National Heritage Study", Helictite 15(2); 1-41
Davey, A.G. & White S., 1986 Victorian Caves and Karst; Strategies for Management. A report to the Caves Classification Committee, Department of Conservation Forests and Lands