Life History, Abundance, Activity, and Special Behaviors
The subterranean biotope is not closed. The Olm's survival is dependent on large aquatic cave systems and the conservation of sylvatic and pastoral land above, as well as clean water. Tourism, economic changes and industrial pollution are the main threats. Other threats to local populations may include water extraction and hydroelectric constrution. The decline of the known populations in Gorizia (Italy), and Postojna (Slovenia) is well established. The scientific needs can be provided by the Proteus breeding program carried out by the Subterranean Laboratory of the CNRS, France. This species must be more strictly protected by law (Gasc 1997).
The Olm is extremely vulnerable to changes in its environment due to its adaptation to the specific conditions in caves. Water resources in the karst are extremely sensitive to all kinds of pollution (Bulog et al. 2002) . The contamination of the karst underground waters is due to the large number of waste disposal sites leached by rainwater, as well as to the accidental overflow of various liquids. The reflection of such pollution in the karst underground waters depends on the type and quantity of pollutants, and on the rock structure through which the waters penetrate. Self-purification processes in the underground waters are not completely understood, but they are quite different from those in surface waters. Among the most serious chemical pollutants are chlorinated hydrocarbon pesticides, fertilizers, polychlorinated biphenyls (PCBs), which are (or were) used in a variety of industrial processes and in the manufacture of many kinds of materials; and metals such as mercury, lead, cadmium, and arsenic. All of these substances persist in the environment, being slowly, if at all, degraded by natural processes. In addition, all are toxic to life if they accumulate in any appreciable quantity.
Slovenian caves became famous for the animals they contained and which could not be found elsewhere. Due to its rarity the Olm is also popular among collectors, leading to possible overcollection. Honnegger (1981) also lists overcollecting, for scientific use or as pig-food by farmers, as a threat to this species.
The Olm is included in Appendices II and IV of the EU Habitats Directive (92/43/EEC). Appendix II seeks to preserve favorable conservation status in animal and plant species along with their habitats by protecting the species or defining special areas of conservation. These areas of conservation form the Natura 2000 network. Appendix IV further defines "animal and plant species of community interest in need of strict protection." Hunting or keeping a limited number of Olms is allowed only under strictly controlled circumstances, determined by local authorities.
The Olm was first protected in Slovenia in 1922 along with all cave fauna, but the protection was not effective and a substantial black market came into existence. In 1982 it was placed on a list of rare and endangered species in Slovenia. This list also had the effect of prohibiting trade of the species. After joining the European Union, Slovenia had to establish mechanisms for protection of the species included in the EU Habitats Directive. The Olm is included in the Slovenian Red List of endangered species. The Postojna cave and other caves inhabited by the Olm were also included in the Slovenian part of the Natura 2000 network.
On the IUCN Red List, the Olm is listed as Vulnerable because of its fragmented and limited distribution and ever-decreasing population.
In Slovenia much of the range lies within proposed national or international protected areas (Kocevski Regional Park; Kraski Regional Park; NATURA 2000 sites). In Italy it occurs within the Riserva Naturale Regionale dei Laghi di Doberdò e Pietrarossa (Stuart et al. 2008).
- Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., and Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.
- Gasc, J.-P. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica, Bonn, Germany.
- Honegger, R. E. (1981). Threatened Amphibians and Reptiles in Europe. Akademische Verlagsgesellschaft, Wiesbaden.
- Stumpel-Rieks, S. E. (1992). Nomina Herpetofaunae Europaeae. AULA-Verlag, Wiesbaden.
- Boehme, W., Grossenbacher, K., and Thiesmeier, B. (1999). Handbuch der Reptilien und Amphibien Europas, band 4/I:Schwanzlurche (Urodela). Aula-Verlag, Wiesbaden.
- Uiblein, F., Durand, J. P., Juberthie, C., and Parzefall, J. (1992). ''Predation in caves: the effects of prey immobility and darkness on the foraging behaviour of two salamanders, Euproctus asper and Proteus anguis.'' Bahavioural Processes, 28, 33-40.
- Griffiths, R.A. (1996). Newts and Salamanders of Europe. T. and A. D. Poyser, London.
- Arntzen, J. W., and Sket, B. (1997). ''Morphometric analysis of black and white European cave salamanders, Proteus anguinus.'' Journal of Zoology (London), 241(4), 699-707.
- Bizjak-Mali, L. (1995). Histological, histochemical and ultrastructural analysis of the digestive tract of Proteus anguinus (Amphibia, Caudata), Master of Science Thesis. University of Ljubljana, Biotechnical Faculty, Department of Biology, Slovenia.
- Bizjak-Mali, L. and Bulog, B. (2004). ''Histology and ultrastructure of the gut epithelium of the neotenic cave salamander, Proteus anguinus (Amphibia, Caudata).'' Journal of Mophology, 259, 82-89.
- Bulog B. (1989). ''Differentiation of the inner ear sensory epithelia of Proteus anguinus (Urodela, Amphibia).'' Journal of Morphology, 202, 325-338.
- Bulog B. et al. (2003). Black Proteus: mysterious dweller of the Karst in Bela krajina . Ljubljana: TV Slovenia, Video tape
- Bulog, B., Mihajl, K., Jeran, Z., and Toman, M. (2002). ''Trace element concentrations in the tissues of Proteus anguinus (Amphibia, Caudata) and the surrounding environment.'' Water, Air, and Soil Pollution, 136(1-4), 147-163.
- Dumas, P. and Chris, B. (1998). ''The olfaction in Proteus anguinus.'' Behavioural Processes, 43, 107-113.
- Durand, J.P. (1976). ''Ocular development and involution in the European Cave Salamander, Proteus anguinus Laurenti.'' The Biologial Bulletin, 151(3), 450-466.
- Gorički, S., and Trontelj, P. (2006). ''Structure and evolution of the mitochondrial control region and flanking sequences in the European cave salamander Proteus anguinus.'' Gene, 378, 31-41.
- Guillaume, O. (2000). ''Role of chemical communication and behavioral interactions among conspecifics in the choice of shelters by the cave-dwelling salamander Proteus anguinus (Caudata, Proteidae).'' Canadian Journal of Zoology, 78(2), 167-173.
- Istenič, L. and Bulog, B. (1984). ''Some evidence for the ampullary organs in the European cave salamander Proteus anguinus (Urodela, Amphibia).'' Cell and Tissue Research, 235, 393-402.
- Istenič, L. and Sojar, A. (1974). ''Oxygen consumption of Proteus anguinus.'' Acta Carsologica, 6, 299-305.
- Istenic, L. and Ziegler, I. (1974). ''Riboflavin as ''pigment'' in the skin of Proteus anguinus L.'' Naturwissenschaften, 12, 686-687.
- Kalezic, M., and Dzukic, G. (2001). ''Amphibian status in Serbia and Montenegro (FR Yugoslavia).'' FROGLOG, 45.
- Kos, M. (1992). ''Fine structure of of the skin of Proteus anguinus Laurenti (Urodela, Amphibia) and comparison of the skin of the pigmentless and pigmented specimen. Unpublished dissertation.''
- Schegel, P., and Bulog, B. (1997). ''Population-specific behavioral electrosensitivity of the European blind cave salamander, Proteus anguinus.'' Journal of Physiology (Paris), 91, 75-79.
- Sket, B. (1997). ''Distribution of Proteus (Amphibia: Urodela: Proteidae) and its possible explanation.'' Journal of Biogeography, 24, 263-280.
- Stet, B., and Arntzen, J. W. (1994). ''A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae).'' Bijdragen tot de Dierkunde, 64(1), 33-53.
- Voituron, Y., de Fraipont, M., Issartel, J., Guillaume, O., and Clobert, J. (2010). ''Extreme lifespan of the human fish (Proteus anguinus): a challenge for ageing mechanisms .'' Biology Letters, Published online before print July 21, 2010, doi: 10.1098/rsbl.2010.0539 .
- NÃ¶llert, A. and NÃ¶llert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.
- Bons, J. and Beniez, P. (1996). Amphibiens et Reptiles du Maroc (Sahara occidental compris). Asociacion Herpetologica EspaÃ±ola, Barcelona.
- Bulog B., and Schlegel, P. (2000). ''Functional morphology of the inner ear and underwater audiograms of Proteus anguinus (Amphibia, Urodela).'' PflÃ¼gers Archive, 439(3), 165-167.
- Istenič, L. and Bulog, B. (1979). ''The structural differentiations of the buccal and pharyngeal mucous membrane of the Proteus anguinus Laur.'' BioloÅ¡ki Vestnik, 27, 1-12.
- Kos, M., Bulog, B., SzÃ©l, A., and RÃ¶hlich P. (2001). ''Immunocytochemical demonstration of visualpigments in the degenerate retinal and pineal photoreceptors of the blind cavesalamander (Proteus anguinus).'' Cell and Tissue Research, 303(1), 15-25.
- Schlegel P. (1996). ''Behavioral evidence and possible physical and physiological mechanisms for earth magnetic orientation in the European Blind Cave Salamander, Proteus anguinus.'' MÃ©moires de BiospÃ©ologie, 23, 5-16.
- Schlegel P.A., Briegleb W., Bulog B., Steinfartz S. (2006). ''Revue et nouvellesdonnÃ©es sur la sensitivitÃ© a la lumiere et orientation non-visuelle chez Proteus anguinus, Calotriton asper et Desmognathus ochrophaeus (Amphibiens urodeles hypogÃ©s).'' Bulletin de la SociÃ©tÃ© herpÃ©tologique de France, 118, 1-31.
- Trontelj, P., Douady, C., FiÅ¡er, C., Gibert, J., Gorički, S., LefÃ©bure, T., Sket, B., and ZakÅ¡ek, V. (2007). ''A molecular test for cryptic diversity in ground water: how large are the ranges of macro-stygobionts?'' Freshwater Biology, 54, 727-744.
No one has provided updates yet.