Non-invasive estimation of brown hare density in Mavrovo National Park, North Macedonia, using the REST model

Effective conservation of predators requires a comprehensive understanding of their prey populations. Being a specialised hunter, the survival of the critically endangered Balkan lynx (Lynx lynx balcanicus) depends on ample amount of the two main prey species, roe deer (Capreolus capreolus) and brown hare (Lepus europaeus). We used the REST model to calculate the density of brown hare in Mavrovo National Park (MNP), North Macedonia. To that aim, we selected four sites near villages within MNP, as the park harbours the majority of the Balkan lynx population. We randomly placed 10 camera-traps with at least 200 m distance in between, aiming at a survey period of 28 days. We focused on agroecosystems with a mix of active and inactive pastures and small agricultural fields. During the entire trapping period we collected 230 videos with hare observations, obtained over a total trapping effort of 867 active trapping nights. The site-specific diel activity pattern of the brown hare reveals distinct periods of inactivity from early morning to late afternoon, with activity levels peaking shortly after this interval. Results show that the density ranged from 3.38–16.45 (SE = 2.08–5.37) brown hares per one km2. This study offers the first-ever density estimation of brown hare in the Balkan lynx range. If repeated and updated, this could potentially inform better management measures for the conservation of the Balkan’s rare cat.