Search

Edge-related increases in nest-predation levels were tested using artificial nests placed within eucalypt forest remnants at distances of 0, 60, and 235 m from edges adjacent to areas of urban, pasture, and Pinus plantation. There were eight replicate sites of each edge type, scattered widely across a 30 000-km2 study region. Open-cup nests containing one quail egg and two plasticine eggs were placed in shrubs and exposed for 6 days. When predation of the quail egg was used to calculate predation levels, predation varied significantly with edge type but not distance to the edge, due to relatively low levels within sites bordering Pinus plantations. When predation of any egg was used to calculate predation levels, predation was not significantly affected by edge type or distance to the edge. Predation levels within eight independent forest interior transects distributed across the study region, and located 500-800 m from the nearest edge, were similar to those within transects 0 m from edges. Birds were the most important class of predator within all combinations of site type and distance to edge, and accounted for 92% of identified predation overall. These results do not support the existence of edge-related increases in predation of shrub nests within subtropical eucalypt forests.

The effects on terrestrial fauna of clearing, fragmentation and regeneration of eucalypt forest and woodland were investigated in a former cattle-grazing area of south-east Queensland. The abundance of species and higher taxa was compared among four major habitat types: interior of relatively mature forest, interior of earlier stages of regenerating forest, cleared pasture, and abrupt edges between the forest and cleared land. The regenerating sites were several decades old and consisted mainly of Eucalyptus saplings 3–6 m high, with a grassy understorey. Numbers of pitfall-trapped invertebrate orders were significantly higher in forest interior and forest edge than in cleared or regenerating sites; numbers of coleopterans were significantly higher in forest interior sites than in cleared or regenerating sites; and numbers of isopterans were significantly higher in both forest interior and forest edge sites than in cleared sites. Total abundance of native non-flying mammals was significantly higher in forest interior than elsewhere. Other vertebrates apart from birds were detected in numbers too low for analysis. Cleared sites supported significantly lower numbers of avian species and Orders, and of total birds, than any other habitat in winter, with a similar but non-significant trend in summer. Forest interior sites showed a significantly higher abundance of several avian species than any other habitat, but noisy miners and Torresian crows were significantly more abundant in edge sites than in forest interior sites. Sites of low regeneration were chiefly utilised by birds characteristic of forest edge. Many decades of regeneration would appear to be necessary before many forest-dependant species are adequately supported in these areas.