Logging and burning impacts on cockroaches, crickets and grasshoppers, and spiders in Jarrah forest, Western Australia

Abstract

In 1985 new silvicultural prescriptions for managing Jarrah ( Eucalyptus marginata) forest in southwest Western Australia came into operation. The most extreme logging treatment involved removal of most of the overstorey from 10 ha patches, followed by a regeneration fire. This study, part of a broader integrated research program, examined the impact of these disturbances on more than 400 species of leaf litter arthropods captured in pitfall traps one year before logging, 1 year before burning, and 4 years after burning. Most species of cockroaches (Blattodea), crickets and grasshoppers (Orthoptera), and spiders (Araneae) were resilient to logging and burning, and immediate decreases in species richness or total abundance were rapidly reversed. Changes in community structure caused by the imposed disturbances were also minimal or short term. Community structure in both the treatment and control sites at the end of the study was different from that at the beginning of the study, perhaps indicative of the overriding importance of climatic variation. The results of this study have broader relevance to understanding the long-term resilience of forest ecosystems in southwest Western Australia. Because of the role of the taxa studied in mediating decomposition, herbivory and predation, these ecosystem processes appear to be robust to the logging and burning prescriptions applied.