The bark of eucalypt trees: habitat quality for arthropods and impact of fire

Abstract

The bark of eucalypt trees is a significant habitat attribute of forests and woodlands, with different bark types supporting varying populations of invertebrate and vertebrate fauna. Bark also contributes to fuel load in wildfires and hazard reduction burning, with a concomitant loss of habitat and modification of habitat resources. We compared the composition and abundance of tree trunk invertebrates inhabiting four eucalypt bark types and determined the impact of burning the bark on population abundance and community composition. Trees of four bark types (gum, box, stringy bark, iron bark) were selected at three sites and arthropod traps placed on burnt and unburnt trees of each type. Traps were left in place for 12 days and arthropod preferences for the four bark types (burnt and unburnt) were analysed. The total number of arthropods differed between bark types, with stringy bark and iron bark supporting the largest numbers of invertebrates and the most diverse communities. Burnt stringy bark and gum bark had reduced arthropod abundance compared to unburnt bark. The study highlights an ecological consequence of fire on an aspect of invertebrate habitat, with flow-on effects for vertebrates, that should be considered in fire management, as greater areas of land are subject to frequent hazard reduction burning in eastern Australia.