Bird populations in exotic pine plantations and indigenous Eucalypt forests in Gippsland, Victoria

Abstract

Bird populations in Pinus radiata plantations of different ages and in native eucalypt forests were studied in Gippsland, Victoria. Few species occurred in pine plantations, particularly the young stands (<5 years old) and species composition changed so that those with certain characteristics were favoured. The commonest species in pine plantations generally were insectivorous, fed on the ground or in the understorey and built open nests in shrubs or trees; herbivorous species and those that fed in the canopy or on boles of eucalypts were uncommon or absent from pine plantations.

The vertical distribution and density of foliage in the lower levels of the forests influenced bird species diversity and composition. The population in pine plantations becomes more similar to that in eucalypt forest as the plantation ages.

Subdivision of the areas studied showed that most birds in dense middle-aged pine plantations were restricted to the edges of compartments. In plantations, areas of native forest, firebreaks, dams or clearings added to diversity of the habitat, and provided for more individuals and species of birds. Ecotonal areas between pine and eucalypt forest were especially important, and supported significantly more individuals than did the adjacent pines.

Birds will probably be less severely affected by conversion of eucalypt forests to pine plantations if plantations are established as a mosaic of different-aged stands, with interconnecting areas of eucalypt forest retained throughout.