Integrating habitat suitability, connectivity, and individual-based models to guide priorities for the creation of a lynx metapopulation in Southeastern Europe

The Balkan lynx (Lynx lynx balcanicus) is the most endangered Eurasian lynx subspecies in Europe, with fewer than 50 individuals facing high inbreeding risk due to isolation and small population size. Genetic reinforcement using the Carpathian subspecies has been proposed to aid conservation, together with the establishment of new protected areas (PAs) and establishing connectivity with neighboring populations. In this study, we first assessed niche overlap between these two subspecies, and then we built species distribution models (SDMs) and computed landscape connectivity with circuit-theory techniques. By integrating habitat and connectivity models, we identified the key areas that could be used as stepping-stone patches. Next, we used individual-based models (IBMs) to assess colonization time and occurrence probabilities within them. Results showed that suitable and connected habitats primarily lie between the Balkan and Dinaric populations, with limited connectivity to the Carpathians. Although these key areas have favorable occurrence probabilities, long colonization time suggests the need for translocations. Moreover, most of these key areas, as well as the corridors among them, are not protected by PAs. Our results have significant implications, revealing the importance of the Dinaric population for potential natural gene flow, and the need for translocations to secure short-term survival of the Balkan lynx. The identified stepping-stone patches could be used to guide the establishment of new PAs in the region, to support natural recolonization and expansion of this population, leading towards the creation of a meta-population that would ensure long-term persistence of the lynx in Southeastern Europe.