In a recently published paper (Fehér et al. 2017) we have reported on the successful reintroduction of a rare and endangered species, the Black Nerite, Theodoxus prevostianus (C. Pfeiffer, 1828).
This is a freshwater neritid species , occurring in hypothermal springs in the Pannonian biogeographical region. Once 15–20 populations were known , but their majority have become extinct in the past 50 years. Now, only four native populations remained: two in Austria (Bad Vöslau and Bad Fischau), one in Slovenia (Bušeča vas) and one in Hungary (Kács). The species is listed by the Annex IV of the European Habitat Directive and assessed as endangered (EN), according to IUCN categories (IUCN 2010).
A reintroduction programme was launched in 2010 in order to re-establish the Black Nerite in the Vízfő Spring (Sály, northeastern Hungary) where the once native population became extinct in the 1970s. This spring was captured then and its outflow was completely dried out causing the extinction of the original native population. As the habitat seemed suitable to host a Black Nerite populations again, 400 adult secimens were translocated in two rounds between 2010 and 2012.
The most noteworthy finding of our program was the long latency of the reintroduced population. At least two years have passed after the second round of translocations and the density of the establishing population still remained below the detection threshold. It seems that the Black Nerite is capable of establishing viable populations under suitable conditions, and thus, its reintroduction (or translocation) to further suitable sites could be the key to the effective protection of this rare and endangered species.