Sex and age mediate the effects of rapid environmental change for a forest carnivore, the Fisher (Pekania pennanti).

This article focuses on how rapid environmental changes affect the survival of fishers (Pekania pennanti), a mesocarnivore with an endangered population in the southern Sierra Nevada, California, United States. Using long-term monitoring data, the study found that fisher survival is influenced by both biotic and abiotic factors, with age and sex mediating these effects: young male survival declined with rising temperatures and increased fungi consumption, while female survival was more resilient to age and diet but benefited from greater forest heterogeneity and declined with higher temperatures and snow depth. The findings highlight the complex interplay between intrinsic factors (age, sex) and extrinsic stressors (climate variables, habitat composition, diet) and suggest that maintaining forest heterogeneity may buffer fishers against climate-related impacts. This research underscores the importance of integrating demographic differences and environmental variables to inform conservation strategies for species facing rapid environmental change.