Antonio Antonucci, Giovanna Di Domenico, Daniela Gentile, Arianna Mugnari, Fausto Quattrociocchi, Laura Scillitani, Fausto Quattrociocchi, Elisabetta Tosoni

Monitoring wide-ranging wildlife populations is challenging in administratively fragmented landscapes, where inconsistent methods and limited coordination undermine conservation outcomes. The Apennine brown bear is one of the world's most endangered bear populations, estimated at around 50 individuals. The population is distributed across a core area of 1,460 km², where most reproducing females occur, and a surrounding low-density expansion area of 3,463 km² spanning three Italian regions. Ensuring reliable, comparable, and long-term monitoring is therefore a conservation priority. Since 2018, the Abruzzo, Lazio and Molise and the Maiella National Parks have jointly implemented a coordinated transboundary Monitoring Network in the expansion area, based on a shared and standardised protocol for data collection and validation. The protocol was informed by an existing bear presence probability model, allowing survey effort to be strategically allocated and thereby maximising efficiency and detection probability. From 2018 to 2024, 137 trained operators conducted (min-max) 190-385 field surveys annually, detecting 154-825 bear signs and 7-45 individuals per year, including in areas that had not been previously surveyed. A major outcome of the Monitoring Network was the revision of the spatial distribution of reproducing females, which revealed a doubling of their occupied range and provided clear evidence of ongoing demographic and spatial expansion of the population. The data collected also informed spatial planning, regulation of human activities (e.g. hunting), and the development of an updated population size estimation protocol implemented in 2025. Despite remaining methodological challenges, this experience demonstrates how coordinated and standardised large-scale monitoring can deliver robust and relevant conservation outcomes. As such, it represents a transferable model for the monitoring of wide-ranging species in fragmented administrative contexts.