Does clearfell, burn and sow silviculture mimic the effect of wildfire? A field study and review using litter beetles

Abstract

The ecological effects of clearfell harvesting followed by high intensity burning are sometimes thought to mimic wildfire, the major natural disturbance regime in Tasmanian wet forests. We investigated whether the litter-inhabiting beetle populations in logged and burnt regeneration forest resembled those in forest regenerating following natural wildfire. Pitfall trapping and habitat assessment were conducted at three pairs of adjacent 33-year-old logging and wildfire regeneration sites. In total, 6128 beetles were collected, representing 179 morphospecies in 30 families. The beetle assemblages in logging and wildfire treatments could not be distinguished. However, beetle populations did differ subtly between sites. One Aleocharinae (Staphylinidae) morphospecies and one Carabidae species were more abundant at one of the three site pairs. Multivariate analyses of common species indicated that the litter beetle assemblages differed significantly between sites, and this was partially related to their degree of geographical separation. Environmental factors considered indicative of logging impacts did not differ between wildfire and logging regeneration treatments. Temporal and landscape scale differences between logging and the natural disturbance regime and changes to logging practices since these study sites were harvested may have negative impacts on litter beetles in the future. Changes to current harvesting practices are recommended to better mimic the natural disturbance regime and thus improve conservation of forest biodiversity.