Fire residuals as habitat reserves for epigaeic beetles (Coleoptera: Carabidae and Staphylinidae)

Abstract

We studied litter-dwelling beetles (Coleoptera: Carabidae and Staphylinidae) in residual patches of unburned forests (fire residuals) left by two natural wildfires in high-elevation coniferous forests in western Alberta, Canada. Fire residuals were wet, late-successional patches of fir and spruce stands, and served as refugia for populations of forest-dwelling beetle species. The largest fire residuals contained older living trees than the mature forest surrounding the burnt areas. Pterostichus empetricola, a glacial relict beetle species, was associated only with habitats provided by the fire residuals. Although there was no relationship between the size of fire residuals and beetle diversity or activity-abundance, more Nebria crassicornis were collected per trap in larger residuals, suggesting dependence of this species on late-seral attributes present within the largest residuals. Conservation of habitats equivalent to fire residuals in managed forests will likely contribute to landscape continuity and preservation of faunal elements common in wildfire-origin landscapes.