Frequent, heterogenous fire supports a forest owl assemblage

Fire shapes biodiversity in many forested ecosystems, but historical
management practices and anthropogenic climate change have led to larger,
more severe fires that threaten many animal species where such
disturbances do not occur naturally. As predators, owls can play important
ecological roles in biological communities, but how changing fire regimes
affect individual species and species assemblages is largely unknown.
Here, we examined the impact of fire severity, history, and configuration
over the past 35 years on an assemblage of six forest owl species in the
Sierra Nevada, California using ecosystem-scale passive acoustic
monitoring. While the negative impacts of fire on this assemblage appeared
to be ephemeral (1-4 years in duration), spotted owls avoided sites burned
at high-severity for up to two decades after a fire. Low- to
moderate-severity fire benefited small cavity nesting species and great
horned owls. Most forest owl species in this study appeared adapted to
fire with the region’s natural range of variation, characterized by higher
proportions of low- to moderate-severity fire and relatively less
high-severity fire. While some species in this assemblage may be more
resilient to severe wildfire than others, novel “megafires” that are
larger, more frequent, and contiguously severe may limit the distribution
of this assemblage by reducing the prevalence of low- to moderate-severity
fire and eliminating habitat for a closed-canopy species for multiple
decades. Management strategies that restore historical low- to
moderate-severity fire with small patches of high-severity fire and
promote a mosaic of forest conditions will likely facilitate the
conservation of this assemblage of forest predators.