European Pond Turtles in Serbia – preliminary data on sexual size dimorphism and demography

Abstract

European Pond Turtles (Emys orbicularis) and their habitats have been receiving great attention of conservationists across Europe. In Serbia, this species is considered strictly protected, although its national Red List status was assessed as Data Deficient (Krizmanić & Džukić 2015). Population studies were initiated only recently, with the financial support of Rufford Small Grant Foundation, on the few localities across Serbia. Here we present preliminary results on morphological differences and basic demographic characteristics of two studied populations at Ludaš lake on North of the country, where Capture-Mark-Recapture studies last since 2011, and Malo Crniće pond in Eastern Serbia explored since 2015. Studied habitats differ in size of the water body, composition of the surrounding vegetation and presence of anthropogenic pressures. Recapture rate was approximately 38% on both populations. In general, European Pond Turtles have females biased sexual size dimorphism (Kaviani & Rahimibashar 2015, but also see Zuffi et al. 2006). At Ludaš population females are heavier and larger sex, according to all measured traits (shell length, width and hieight). On the other hand, in population from Malo Crniće sexual dimorphism is significant only in weight and shell height. Our sample shows that turtles from Malo Crniće, both males and females, grow to be larger and heavier comparing to those from Ludaš lake. This difference could be due to large eutrophication of the small isolated pond, along with additional nutrients such as carcases from illegal dumping site next to the pond.