Impacts of timber harvest intensity on invertebrate biodiversity

The intensity of timber harvest is believed to have significant impacts on biodiversity values and the overall health of forest habitats. The extent and importance of these impacts is an emotive issue and objective reporting of effects of timber harvesting and silviculture on biodiversity is a significant challenge to forest managers. Rapid assessment of invertebrate biodiversity may provide a solution to this need. Pitfall trap samples of litter invertebrates from pastures, unlogged forest compartments, forest compartments previously harvested at 50% of usable timber and forest compartments with standard harvest conditions, involving the removal of 70–90% of all stems, were compared. There were significant differences in invertebrate abundance, richness and composition between forest and pasture habitats, but no detectable differences between forest treatment categories. Strong site effects on abundance, richness and composition were apparent. Pastures and each forest treatment category contributed unique morphospecies to the sample set. More than 20 y of post-harvest recovery has allowed invertebrate assemblage composition to converge to the extent that harvest effects are not readily detectable within this component of biodiversity. The value of invertebrate assessments as a solution for objective reporting of biodiversity value is discussed.