The short-term effects of edges created by forestry operations on the bird community of the jarrah forest, south-western Australia

Forestry operations in jarrah forests of south-western Australia use two types of selective logging, gaps which remove 85-95% of basal area and shelterwoods which remove 40-60% of basal area. These operations create considerable lengths of forestry edge (edges between logged and unlogged forest) each year, but their impact on the avifauna of the jarrah forest is unknown. Changes in bird density were examined along edges created by forestry operations in jarrah forests using a BACI design experiment. Bird densities were estimated on 1-ha plots that were surveyed three times per season, in three seasons both before and after logging. There was no evidence of edge effects at the community level; overall bird density and species richness did not changes along forestry edges. Scarlet robin (Petroica multicolor) abundance increased significantly along both gap and shelterwood edges, relative to controls. Apart from a probably spurious increase in density along gap edges by red-winged fairy-wrens (Malurus elegans), no other species showed a significant change in density along edges. There was also no difference in responses to gap and shelterwood edges, despite gaps removing more basal area than shelterwoods, suggesting that response to forestry edges in the jarrah forest may be threshold dependent, rather than increasing with increasing intensity of logging operations. Comparisons with other studies examining density changes along forestry edges in south-western Australia suggest that density changes observed in this study are short-term in nature. The limited density change in avifauna along forestry edges is probably because selective logging practices were examined instead of clear-felling. Studies in the literature indicate that this pattern is likely to be true for many forest ecosystems