Livia Chavko, Sapienza University of Rome

The Apennine brown bear (Ursus arctos marsicanus) is a relict, long isolated, and highly inbred population facing a higher extinction risk over the next century than previously recognized. While genetic rescue is currently considered risky on genomic and social grounds, population expansion beyond its current historical stronghold has been identified as the most effective conservation strategy. Previous modelling has suggested that adequate landscape suitability exists across the central Apennines, with at least 15 interconnected Critical Conservation Areas (CCAs, high suitability patches ≥ 70 km2), many of which largely overlap with existing protected areas. On this basis, the current conservation strategy for the Apennine brown bear aims to establish a metapopulation structure across the central Apennines. However, no quantitative assessment has been conducted to determine whether a hypothetical metapopulation across the Apennines would result in a significantly lower extinction risk than the current single core population. In this work, we use Vortex to examine whether, and under which structural conditions, such a metapopulation would ensure a substantially lower extinction risk. Specifically, we compared the extinction risk of a hypothetical metapopulation spanning the maximum possible extent, centred on the 15 CCAs across the central Apennines, with that of smaller subsets of interconnected subpopulations located closer to the current core population, representing a more realistic conservation scenario over the next one or two decades. While fully aware that our projections are highly sensitive to the uncertainty of key parameters characterizing the simulated metapopulation, we consider the results valuable because they provide unique insights: both for evaluating the effectiveness of the current conservation strategy and for identifying the population parameters that are most critical to estimate and monitor during the anticipated range expansion.