Local and Invasive Species of Freshwater Turtles (Reptilia: Emydidae, Geoemydidae) in the Eastern Part of Strandzha Nature Park (Bulgaria) - Distribution and Populations Assessment

The current study presents data on the distribution, abundance, density, sex and age ratio of the populations of two freshwater turtle species - Emys orbicularis (Linnaeus, 1758) and Mauremys rivulata (Valenciennes,1833) in selected wetlands in the eastern part of "Strandzha" Nature Park. During the research period were recorded a total of 142 ind. of E. orbicularis and 65 ind. of M. rivulata. Two single localities of the invasive species Trachemys scripta elegans (Wied-Neuwied, 1839) have been documented as well. Morphometric characteristics and body condition index of the captured individuals is also presented. Unmanned aerial vehicles (drones) were used for video recording of some sections of the studied transects, testing their possible usage for monitoring purposes. The current conservation status and threats for the studied species are also discussed.