Olm Salamanders discovered with use of environmental DNA

A type of Balkan Salamander called olms are endangered by pollutants, and endeared by Croatian locals who refer to them as ‘baby dragons’. However, it is hard to protect and conserve what you cannot see. That was, until now.

The olms have been previously found in only 10 caves, in rare instances where they have been washed out by heavy rainfall or spotted by cave-divers.

Knowing where the salamanders are is important because they are vulnerable to pollutants above their caves. However, with more than 7,000 caves in Croatia, it was difficult to detect which ones might contain olms. Waiting for rainfall doesn’t guarantee a sighting, as the salamanders can try to prevent being washed out – and most caves are inaccessible.

Recently researchers discovered a new method of detecting the caves where the salamanders are present: isolating environmental DNA (eDNA). Using a special paper that filters water coming out of the caves, researchers are able to isolate eDNA in the form of salamanders’ traces, such as faeces or shed skin.

Judit Vörös from the Hungarian Natural History Museum tested this method in Croatia during the summer of 2014. 15 caves were tested for the species: their presence was confirmed in the 10 known caves and detected for the first time in five others, making protecting these sites from pollutants easier in the future.

Vörös expressed some reservations about this method because, while it can successfully identify salamanders in cave systems, it is unable to narrow it down to a specific cave in all instances.

We can now be confident that ‘baby dragons’ aren’t as rare as we thought, however. Back when only 10 caves were identified, the salamanders were listed on the IUCN Red List of Threatened Species, a highly influential list in determining the allocation of conservation resources.

The creature itself is blind and completely aquatic. They exclusively live in caves, many of them underground, and lack any pigmentation, giving them a pale skin tone across all of their bodies except their gills. Their eyes are below the skin, and although they cannot see, they retain sensitivity to light not just in their eyes but throughout their skin.

This new method will afford us the opportunity to continue to learn more about this strange species.

Image: Ranko

 

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