How will low-intensity burning after clear-felling affect mid-boreal insect assemblages?

Intensive forest management and fire protection programs have dramatically reduced the frequency of fires and this is believed to have negative effects on biodiversity. As a result, fire is used as a restoration tool to improve conditions for fire adapted/favoured species. The aim of our study was to determine how burning of clear-felled areas (i.e. those typical of real-world management in Fennoscandinavia) influenced beetle assemblages, and to identify taxonomic and functional groups and individual species that are favoured by burning as it is currently practiced. We studied five sites, each consisting of one burned and one unburned clear-cut. Beetles were collected in sixteen pitfall traps per site for three consecutive years. Regardless of whether beetles were divided into taxonomic or functional groups, abundance was generally higher on burned clear-cuts, with the exception of Staphylinidae which showed indications of an opposite response. The species assemblages differed significantly between burned and control clear-cuts in all years. The species contributing most to the difference included Corticaria ferruginea, Pterostichus adstrictus, Corticaria rubripes, Atomaria pulchra and Hylobius abietes (all more common on burned clear-cuts), and Drusilla canaliculata and Atomaria peltata (more common on controls). We also found a succession of species, i.e. Otiorhynchus nodosus and Anthicu.v ater became dominant species on burned clear-cuts the third year after burning whereas C. ferruginea and A. pulchra became scarce. In conclusion, clear-cut burning clearly changed the assemblage composition of beetles and seems to benefit at least some species associated with natural fires. Thus, although clear-cut burning cannot exactly emulate the effect of natural fires it could be used as a restoration tool for improving the quality of the matrix outside protected areas and in particular to create habitats for disturbance-associated species, including species associated with fire.