Fire and food: how do insectivorous small mammals respond to urban wildfires?

Wildfires are increasingly impacting ecosystems worldwide, with notable consequences for wildlife communities, especially in already disturbed and dry areas such as cities. Small mammals, particularly insectivorous species within the order Eulipotyphla (shrews, hedgehogs, and moles), are remarkably susceptible to fire-related disturbances due to their high dependence on ground cover and invertebrate prey. Hereby, we investigated the direct and indirect effects of wildfire on small mammal communities in two urban parks in Rome, Italy, with a focus on the influence of habitat structure and prey availability. A paired treatment-control design was implemented to sample small mammals and orthopterans, used as a proxy for invertebrate prey, in both burnt and unburnt plots across grasslands, woodlands and shrublands. Structural equation modeling (SEM) was used to evaluate the relationships between small mammal diversity and wildfire occurrence, habitat type, prey abundance and diversity. We showed that wildfire significantly reduced small mammal diversity, with the strongest effects observed in Eulipotyphla species. Although wildfire led to an increase in orthopteran abundance, it also reduced orthopteran diversity. A positive relationship was found between Eulipotyphla diversity and orthopteran abundance, suggesting a potential indirect benefit of fire through increased prey availability. Our findings showed the influence of wildfire, habitat structure, and trophic dynamics in shaping small mammal communities in urban parks subjected to wildfire, emphasising the importance of integrating both direct and indirect effects, as well as functional group responses, in the assessments of wildfire impacts on terrestrial fauna.