Behavior of brown bears under fluctuating resource availability

Mast seeding, the variable and intermittent production of seeds, have cascading effects on ecosystem functioning. This study explores its influence on the brown bear populations in the Italian Alps, focusing on beech nuts, the primary food source for bears in the region. Using the MASTREE+ historical data database, field sampling, and contributions from the 'Centro Nazionale Carabinieri per la Biodiversità di Peri,' we estimated and mapped the annual seed biomass from 2007 to 2021 in a GIS. The energy content of beech nuts was assessed through high heating values (HHV), providing the caloric resources available. Concurrently, we integrate GPS collar data from 18 bears, showing diverse patterns of space utilization. We found a correlation between mast seeding and decreased damages to agriculture and livestock, suggesting that bears met their trophic needs through natural food sources. This work provides insights on the ecological dynamics and conservation implications of brown bear in the study area by mapping the spatial and energetic aspects of mast seeding.