Stygofauna
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Stygofauna are any fauna that live within groundwater systems, such as caves and aquifers, or more specifically small, aquatic groundwater invertebrates, though terrestrial air-breathing subterranean animals are also sometimes included. Stygofauna can live within freshwater aquifers and within the pore spaces of limestone, calcrete or laterite, but are also found in marine caves and wells along coasts.
Extensive research has been done into the stygofauna of the USA, France, Slovenia and numerous other European countries, due to easy accessibility of caves and wells in these regions, as well as the high diversity and numbers of animals present here. Many species of stygofauna, especially obligate stygofauna, are endemic to particular regions or even particular caves. This makes them focal points for conservation of groundwater systems.
[edit] Conservation
An Australian Perspective
As Australian stygofauna are a relatively poorly understood, new classification of animals, and live in a poorly understood environment, much effort is being put into understanding their ecology, life cycle and how to protect their habitat.
Many species of Australian stygofauna have been found only in Australia or in particular regions within the country. This has restricted extraction of groundwater, drilling of new holes and excavations within their aquifer habitat. This protection is currently challenged by mining and pastoral interests.
Stygofauna have been used as environmental bargaining chips, as reasons to delay or prevent mining operations by various environmental groups and proponents of stygofauna research and taxonomy, arguing that stygofauna are, by dint of their habitat in restricted aquifers, extremely biologically important.
Mining companies and pastoralists are opposed to classification of stygofauna as endangered species as no causal link between mining operations and stygofauna extinction has been proven. They further argue that in the extremely arid Australian landscape the stygofauna must be able to weather drought conditions. This is questioned by stygofauna researchers, who identify groundwater habitats as refuges for many species that would not survive in the otherwise arid environment. Furthermore, the ecological value of stygofauna is unknown in Australia, as is the theory of their restricted occurrence, because little thorough research has been done into all species of stygofauna present. Additionally, studies have tended to focus on only easily accessible or highly sampled areas of Australia, so overall patterns of distribution and endemicity are not known.
It is not practical or possible to conserve all stygofauna habitats in Australia, because drilling of new holes, extraction of groundwater and excavations must take place to sustain the human population. It has been suggested by other researchers from overseas to identify 'hotspots' of stygofaunal biodiversity and endemicity, so that the most biologically important areas or systems can be conserved. This is currently difficult in Australia due to the poor knowledge of many classes of organisms that reside in groundwater habitats. Further research is required to identify the most important groundwater areas to look after, as has been done with surface waters like rivers and lakes.
An Australian Conservationists Perspective
The knowledge concerning Western Australian Stygofauna is growing daily and the Pilbara Biological Survey (PBS) has added much to date. Many species once thought to be restricted to a single aquifer and now known to be much more widespread than previously thought. Genetic taxonomy has been one method used in this regard.
The explosion of iron ore mining in the Pilbara, Kimberley and Midwest regions of WA over the previous decade has also facilitated the explosion of knowledge concerning WA stygofauna - which is now believed to be a world hotspot for such taxa - see New Scientist for example. Stygofauna can be viewed in a similar context to surface water aquatic invertebrates in that they help to maintain the quality of groundwater which sustains many rural, arid Australian populations and businesses. Also, having descended into the subterranean environment to survive the aridification of Australia that has occurred in the recent geological past, one can view them as "seeding" animals, that would again inhabit the inland rivers of WA should the climate become tropical once again. Scientifically these animals are extremely important because they directly demonstrate plate tectonic theory - that is, the relatives of some of these ancient groups exist only in other continents and the fossil record, thus tying the Australian continent to South America, Asia and Africa.
To date only a small handful of mining projects have been held up by the discovery of stygofauna on their leases. And where it has, it has been because the resident stygofauna are found no where else on earth and the proposal has been considered to be likely to lead to the extinction of those species due to groundwater extraction for ore processing, potable water supplies or pit dewatering activities.
Pastoralists are very rarely impacted by the presence of stygofauna or expected to conduct stygofauna surveys. This is because they require so little groundwater that stygofauna habitat is unlikely to be removed by these users. Mining operations on the other hand require comparatively large quantities of groundwater for ore processing and potable water supplies and thus could easily remove all stygofauna habitat from a particular aquifer without adequate controls being put in place.
Current WA legislation is out-dated having been enacted in 1950 (Wildlife Conservation Act 1950). Not surprisingly it does not protect invertebrate fauna unless listed as protected at the individual species level. A range of invertebrates are presently listed including particular species of ants, beetles and spiders as well as some subterranean fauna species such as stygofauna and troglofauna.
There is no specific provision in the Wildlife Conservation Act that protects species from extinction. Permission to commence development that is likely to cause the extinction of a species is subject to approval from the Minister for the Environment under the Environmental Protection Act (a decision that usually would involve an environmental impact assessment by the EPA). Where knowledge of the distribution and abundance of invertebrate subterranean is incomplete, the precautionary principle and principle of intergenerational equity may guide the EPA's environmental impact assessment process. Where a risk of species extinction exists, a development proponent may be required to devise management strategies to mitigate potential impacts on species to make the development proposal environmentally acceptable.
Conserving all stygofauna habitats is not currently the aim of the regulatory authorities in WA. The aim as with all species, habitats and environments is to conserve a selection of 'representative' habitats and environments that have the best chance of conserving resident fauna. The conservation of all 'significant' stygofauna species is achievable. Where a development project can not operate without risking the extinction of a species, it would be arguable that because the principle of intergenerational equity and the precautionary principle cannot be satisfied such a project should not be approved. However, under the WA Environmental Protection Act, the Minister for the Environment may take into account relevant factors other than environmental factors (such as economic and social benefits). It is at this point in the development approval process that political considerations are imperative and it is critical to ensure that those in political office are fully cognizant of the need to manage and protect the world's biodiversity.
[edit] Collecting stygofauna
Several methods are currently used to trap stygofauna. The least harmful (but very expensive) method is to use a downbore video camera, the more traditional method is to drag a modified plankton net several times through the bore or sinkhole. A more destructive method is to pump bore water through a sieve on the surface. Recently a stygofauna trap was successfully deployed in the Pilbara on the Telfer Mine site, whilst this method requires further examination it has already demonstrated its versatility.
