The territory of Croatia is inhabited by two species of freshwater turtles. Unlike the European Pond Turtle (Emys orbicularis) which is widespread throughout the country, the Balkan Terrapin (Mauremys rivulata) is one of the most endangered reptile species in Croatia. It is present only in the country's far south which is the most northern and most western part of the species range.
The Croatian Herpetological Society-Hyla has conducted preliminary studies on the Balkan Terrapin from 2004 to 2009. Their objective was to list all localities where the Balkan Terrapin had been recorded, to define the species distribution in Croatia, and to estimate the approximate population size using the capture-mark-recapture method. The species' habitat preferences were described and its potential threats were investigated.
Five years long survey showed that the Balkan Terrapin occurs in three geografically isolated populations (Gornji Majkovi, Ston, Konavle field) and counts approximately 600 individuals. It is strictly protected by the Nature Protection Act and is categorized as Endangered (EN) in the Red book of Croatian Reptiles and Amphibians. It is also included in several international nature protection legislations such as the Annex II and IV of The Habitats Directive.
The Balkan Terrapin inhabits rivers, streams, canals and ponds rich in aquatic vegetation and with muddy bottoms. It is primarily threatened by the habitat loss given that in Croatia such water habitats are dissapearing due to succession or are converted into arable land. Members of CHS-Hyla held several educational workshops on the threats to the turtle and the importance of its conservation. As a result, one of the areas inhabited by the Balkan Terrapin - Gornji Majkovi was declared a Herpetological Reserve, an educational bilboard was placed and two ponds were cleaned with the help of the local community.
Although the Balkan Terrapin is globally assessed as a species of Least Concern (LC), the extinction of entire populations in the western part of its range is recorded (Crete, FYR of Macedonia, Turkey). A drastic reduction of the Ston population size over the last 20 years in Croatia is also noted. Today, the Ston population is considered potentially extinct given that the last record of the species occurance dates from 2009. However, a few individuals of the Balkan Terrapin were found on a new locality in 2012, in the area of the Neretva river. Distribution and size of this population is still to be explored. In the course of 2013 CHS-Hyla will continue with more detailed population studies in the area of Konavle field, including the DNA sampling, animals measuring, bacteriological, virological and parasitological analysis. One of the goals is the establishment of the Centre for the in situ conservation of the Balkan Terrapin. The creation of the Management and Action Plan for the protection of the Balkan Terrapin in the region is planned in the near future, in cooperation with the colleagues from BiH, Montenegro, Albania and FYR of Macedonia.