Homing through ecological barriers in Balkan pond turtles

Homing behaviour, the tendency to return home from a place outside an individual's home, requires an ability to navigate by integrating inputs from natural cues. While navigation has been extensively studied, it remains taxonomically biased, mainly focusing on birds. We used the ATLAS tracking system to test homing behaviour of the Balkan pond turtle (Mauremys rivulata), a semi-aquatic reptile. Thirty-six turtles were displaced up to 2.5 km from their capture location and tracked to test for homing behaviour. Another five individuals were released in their capture location as a baseline for local movement. A correlated random-walk model was developed, simulating movement patterns fitted to match turtle movements. Most displaced turtles successfully returned or headed towards their home range within 1-3 days, travelling significantly greater daily distances within those days. Homing turtles showed a more direct and shorter delay than simulated or undisplaced turtles. Our high-resolution tracking revealed that water conduits served as eco-hydrological barriers, causing substantial delays or preventing turtles from passing through the water. Taken together, we demonstrate the navigation capability of the Balkan pond turtle, placing this species as a potential model system for navigation research and conservation biology, specifically as an indicator of wetland connectivity.