Cave Dwelling Invertebrates: Possible bioindicators of pollution in Italian caves.

ABSTRACT Contrib. Nat. Hist. 12: 1029–1047. Cave and underground environments are dwelling places for an endemic and rich but fragile invertebrate fauna, which is mainly dependent on outside autotrophic foodwebs. Organic matter and pollutants enter the cave and are ingested by living organisms. In a field study of floor mud, guano deposits, cave water, and some cave dwelling invertebrates found in eight natural carsick caves in the Veneto region of Italy, the concentration of some heavy metals (HM), e.g. Cd, Cr, Cu, Pb, Zn, were measured. In caves with heavy bat guano deposits, Cu and Zn pollution was very high (copper 132–2179 mg/kg and zinc 590–2090 mg/kg). Other HM were detected in various and not so high amounts in the cave mud. No accumulation along the cave foodchain was detected, as predators did not have higher HM contents than detritivores. In most cases the troglobitic specimens showed higher HM concentrations than topsoil invertebrates. Cr content was high both in mud and in detritivorous cave dwelling invertebrates such as Typhloiulus tobias (millipede). Some troglobitic species accumulated Cu, Zn, and Cd. Therefore the millipedes T. tobias and Serradium in addition to other invertebrates such as terrestrial isopods (Androniscus, Spelaeonethes) can be proposed as bioindicators to monitor the underground environments.