Trunk invertebrate faunas of Western Australian forests and woodlands: Influence of tree species and season

Trunk-associated invertebrates were sampled on two rough-barked tree species (jarrah, Eucalyptus marginata and marri, E. calophylla) at Karragullen, in the hills near Perth, Western Australia, and on these two species plus two smooth-barked species (wandoo, E. wandoo, and powderbark wandoo, E. accedens) at Dryandra, a drier site situated 150 km to the south-east. Invertebrates were sampled by intercept traps, which collect animals that attempt to land on the trunks, and photo-eclector bark traps, which collect invertebrates that move, or live, on the trunk. The range and abundance of invertebrates sampled was generally greater in the intercept than the bark traps. Invertebrate abundance and activity (but not biomass) on bark was strongly seasonal, with greater numbers being found during the moister periods. The two smooth-barked species supported, and were visited by, more invertebrates than the two rough-barked species. There was some evidence that jarrah supported more invertebrates than marri at both Karragullen and Dryandra, although the results were equivocal. Within the two smooth-barked species, wandoo tended to support more invertebrates than powderbark wandoo. These trends are discussed in terms of the characteristics of the bark of these trees and the environments in which they occur.