Epikarst communities: biodiversity hotspots and potential water tracers

There is an exceptionally rich aquatic fauna in the epikarst, the skin of karst. High species richness in the epikarst, coupled with its special vulnerability as the first point of entry of nearly all toxic spills, makes its protection especially important. The epikarst fauna may also be an useful tool in tracing the potential route of pollutants. Copepods in epikarst have extremely local distributions, and their body size is such that they are largely at the mercy of directional flows. In a series of caves in southwest Slovenia and West Virginia, a significant fraction of the copepod species occur in less than 100 m of linear extent. This suggests a pattern of highly restricted lateral flow under normal conditions and the distribution of copepods could potentially be used to trace water movement. Under high flow conditions as would often be the case with toxic spill, mounding of water may increase the lateral radius of flow. Nevertheless, copepods may be useful tracers.