Karst caves fauna
Karst caves are the most prominent characteristic of conglomerate karst in Udin boršt and are, as every cave in Slovenia, classified among natural resources of national importance. 14 caves have been registered in Udin boršt to date. Currently the longest cave is Arneševa luknja with 815 m and there are three more which are longer than 200 m of which two are longer than 500 m. All the other caves are smaller and are situated on the brink of the terrace. Some continue in smaller tunnels which have collapsed further on.
The entrances into bigger caves are points of outflows from the terrace and in the past these points were used as water resources by locals. The conglomerate terrace with impermeable
grey marly soil known as Oligocene dark-greenish-grey clay underneath represents fairly simple speleological frame. Rainwater by dispersion and concentration over numerous sinkholes leaks through conglomerate reaching impermeable surface and along this juncture flows to the brink of the terrace. Water flow dissolves carbonate binder and gravel-stones which creates new canals.
Caves in Udin boršt have tree-like structure with the main canal into which all the small tunnels flow together.
The following caves are among the most known ones:
Unfortunately, Kačja jama has been used for decades as a dumping ground for various types of waste. During one of the clean-up projects by the Železničar caving club and locals, they collected 3 m3 or 0.5 t of waste. The waste was predominately of animal origin (heads, entrails, skin, cadavers etc.). This is extremely dangerous as it could contaminate drinking water in the nearby spirings and reservoirs. Rainwater accumulates in Kačja jama which leaks into underground until it reaches underground water in karst aquifer. The water flows through many tunnels into springs on the brink of the terrace where there are around 40 springs. Some were changed into water reservoirs to serve as drinking water resources. In the proximity of Kačja jama there are water reservoirs for Spodnje Duplje and east from Nacovce and Velika Lebnica for Strahinj.
Karst caves fauna
Karst caves are the most prominent characteristic of conglomerate karst in Udin boršt and are, as every cave in Slovenia, classified among natural resources of national importance. 14 caves have been registered in Udin boršt to date. Currently the longest cave is Arneševa luknja with 815 m and there are three more which are longer than 200 m of which two are longer than 500 m. All the other caves are smaller and are situated on the brink of the terrace. Some continue in smaller tunnels which have collapsed further on.
The entrances into bigger caves are points of outflows from the terrace and in the past these points were used as water resources by locals. The conglomerate terrace with impermeable
grey marly soil known as Oligocene dark-greenish-grey clay underneath represents fairly simple speleological frame. Rainwater by dispersion and concentration over numerous sinkholes leaks through conglomerate reaching impermeable surface and along this juncture flows to the brink of the terrace. Water flow dissolves carbonate binder and gravel-stones which creates new canals.
Caves in Udin boršt have tree-like structure with the main canal into which all the small tunnels flow together.
Karst caves fauna
The underground fauna of Udin boršt has not been properly researched yet. All the data consists of notes taken during fieldwork and occasional observations predominately by speleologists while exploring caves. In all four caves, the ones that have been explored so far, they found arachnids, isopods, cave beetles, dipterans, grasshoppers, salamanders and bats. In literature there are records of Proteus anguinus which apparently resides in the underground waters of Udin boršt. Our guess is that the underground fauna of Udin boršt is much more diverse than the research done so far suggests.
People and karst caves
In the past Udin boršt, especially karst caves, played an important role in the lives of locals. The caves were used as a shelter and hideout. Valvasor mentioned 4 caves of which only Aneševa luknja is recognized. He describes it as a hideout for locals against Turks. Vrhovnik (1885) wrote that Boltar family in Spodnje Duplje kept the metal door which was closing the entrance of Arneševa luknja until the end of the 19th century. Almost two centuries after Valvasor, Vrhovnik (1885) named 4 caves which are today registered in the cave cadastre with the same or slightly changed name: Lebinica, Zijalka, Luknja v Voglu (today Arneševa luknja), Dopulnik, Boltar, Veliki and Mali Pekel (big and small hell). The caves were an important hideout later on when the attacks of Turks ended (e.g. under the French rule and during World War II).
