2003. A particular case and a general pattern: hyperaggressive behaviour by one species may mediate avifaunal decreases in fragmented Australian forests. -Oikos 101: 602-614.We quantitatively assessed edge effects associated with elevated abundance of a hyper aggressive bird species, the noisy miner Manorina melanocephala, in fragmented eucalypt forest adjoining developed land. Long-term data from Toohey Forest, subtropical Australia, show that noisy miner colonies intensively occupy a zone of 20 m from the forest edge, with frequent use occurring up to 100 m from the edge, but little beyond 200 m. Within noisy miner colonies, the abundance and species richness of other birds were both about half those recorded at nearby transects which were outside the colonies' main activity area. Bird species smaller than noisy miners, which are also those with similar diets, were collectively 20 -25 times more abundant, and their species richness tenfold greater, outside miner colonies than within them, whereas larger species, which have less dietary overlap, did not differ. Exclusion of small insectivorous birds has been hypothesised to cause elevated insect herbivore density, but we found no difference between tree crown defoliation or dieback rates within versus outside miner colonies.Aggression by noisy miners can be viewed as a mechanism of interspecific competition, since miners have a relatively large body size for their diet and are hence able to exclude virtually all potential competitors at relatively little cost. We examine evidence indicating that reduced bird diversity in eucalypt forest fragments of eastern Australia is often simply the effect of noisy miner occupancy of edges, acting directly on the densities of other species through their aggressive behaviour. With an edge effect 200 m deep, a remnant 10 ha in size is likely to become entirely occupied by noisy miners, and this is a size threshold that has been commonly reported in association with area-standardised avian diversity reductions. Convergent patterns of species loss from small forest fragments in different continents are the result of different underlying ecological processes.

Despite recent efforts to reforest cleared rainforest landscapes, in Australia and elsewhere, the value of reforested sites for rainforest-dependent reptiles is unknown. We surveyed the occurrence of reptiles in a range of reforestation types (monoculture and mixed-species timber plantations, diverse ''ecological restoration'' plantings and regrowth), as well as reference sites in pasture and rainforest, in tropical and subtropical Australia. We recorded 29 species of reptiles from 104 sites, including 15 rainforestdependent species. Most rainforest reptiles were strongly associated with complex microhabitats (tree trunks, logs, rocks). The richness and abundance of rainforestdependent reptiles varied between the different types of reforestation and between regions. In the tropics, rainforest reptiles were recorded in old timber plantations and ecological restoration plantings but not in young timber plantations or regrowth. Rainforest reptiles were recorded in few reforested sites in the subtropics. The occurrence of rainforest-dependent reptiles in reforested sites appears to be influenced by (1) habitat structure; (2) proximity to source populations in rainforest; and (3) biogeography and historical differences in the extent of rainforest. Restoration of cleared land for rainforest-dependent reptiles may require the development, or deliberate creation, of complex structural attributes and microhabitats in reforested sites. Where reforested sites are located away from rainforest, recolonization by rainforest reptiles may require the construction of corridors of suitable habitat between reforested sites and rainforest or the translocation of reptiles to reforested sites.

Aim  Urbanization and deforestation are important drivers of biodiversity change. However, long‐term changes in faunal communities within urbanizing regions are poorly understood. We investigated how well observed community changes in both space and time agree with expectations based on current paradigms in urban ecology. Location  Greater Brisbane region, Australia. Methods  We compared bird assemblages in two time‐periods 15 years apart, at multiple sites in remnant forest and residential suburbs across an urbanizing landscape. Differences in assemblage composition, species abundances and functional groupings were assessed within and between habitats. Results  Compared with forest, suburbs in both time‐periods had over twice the total bird abundance, a different species composition, greater between‐site community similarity, a greater proportion of non‐native species and greater dominance by large‐bodied species. These differences corresponded with changes in sites whose habitat was converted from forest to suburb. Between time‐periods, abundances of 58% of suburban species changed significantly compared with those of 11% in forest. Increaser species outnumbered decreasers in suburbs, with the reverse in forest. Abundance of small‐bodied birds decreased 70% in suburbs and 20% in forest. Broad‐spectrum competitors and nest predators were common among suburban increasers. Among invasive species, the number of increasers was counterbalanced by decreasers. Both site‐scale species richness and between‐site community similarity increased to a small extent in both habitats. Main conclusions  Species composition and ecological function of suburban bird communities were very dynamic. Suburban assemblages were neither a subset of forest species nor an increasingly non‐native compilation. Communities in large forest patches were comparatively stable. The notion of habitat‐specific species turnover better characterizes the nature of most changes than either species decline or homogenization, even though both of these were evident. There is considerable scope for careful urban planning, focused on both among‐ and within‐habitat variety, to sustain bird diversity in urbanizing landscapes.

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Ecological degradation within areas of remnant forest may be amplified if the effects of fragmentation interact with the effects of other environmental disturbances such as wind storms. We used before-after comparisons to assess the effects of Tropical Cyclone Larry on remnant and continuous rainforest in the Wet Tropics uplands of north-eastern Australia. Vegetation structure was measured 3 years before the cyclone and 6 months afterwards, at eight continuous forest sites and eight remnants (6-37 ha), within 20 km of the cyclone's track. The cyclone caused extensive defoliation, felling and breakage of stems and branches (greatest among the trees >100 cm diameter which had around 50% stem loss), and increased litter and woody debris. Cyclone effects were strongly influenced by a site's spatial position (P = 0.005, 0.001 in multivariate analyses of overall damage). Maximum damage occurred 10-15 km south of the cyclone track, perhaps because of the additive effects of the west-moving air at the southern eyewall combined with the cyclone's own rapid westward movement. Most fragments were south of the cyclone track, as a consequence of spatially selective deforestation practices, and therefore, showed greatest damage. However, once the effects of spatial position were considered, the independent differences in cyclone effects between fragments and continuous forest were lost (P = 0.23, 0.41 when north-south distance was included as a covariate in analyses). The expected protection afforded by a continuous forest canopy seems to have disappeared in the face of extremely strong cyclonic winds and down-draughts. Nevertheless, an interaction between fragmentation and disturbance may yet occur, during the period of post-cyclone recovery, owing to the effects of landscape context on plant recruitment. For example, there was a higher diversity of exotic seedling germination in fragments, independent of the extent of cyclone damage.