No abstract

Three threatened black cockatoos inhabit the Jarrah Eucalyptus marginata-Marri Corymbia calophylla forest of southwestern Australia: Baudin’s Cockatoo Calyptorhynchus baudinii, Carnaby’s Cockatoo C. latirostris, and Forest Redtailed Black Cockatoo C. banksii naso [FRTBC]. Their local ecology in relation to anthropogenic disturbance is poorly known, hampering effective conservation management. Therefore we studied their group size, site occupancy patterns, habitat use, and food plants at a mine-site and its surrounds in the eastern forest over three years. FRTBC showed similar group sizes and occupancy across seasons, suggesting year-round residency and no marked seasonality in movements and grouping patterns. In contrast, Carnaby’s Cockatoos were up to twice as abundant in spring and summer, indicating migrating or transient flocks and some year-round residents. Few Baudin’s Cockatoos were present in summer, but their abundance increased at other times. All three cockatoos were observed in modified or humanmade habitats such as mine-site rehabilitation, farm paddocks, and pine plantations. Carnaby’s Cockatoos used the broadest habitat range. We documented feeding on 16 plant species, with Carnaby’s Cockatoos eating at least 10. Examination of feeding residues as well as observations of behaviour were essential to obtain a complete picture of feeding. Current mine-site rehabilitation protocols provide food for all three black cockatoos within a decade and should continue to do so long-term if Marri is maintained in the seed mix. However, because climate change scenarios predict declining rainfall over much of southwestern Australia, the plant species used to revegetate mine-sites and other landscapes may need to be reconsidered. For areas that do not specify restoring a jarrah forest landscape, the selective use of exotic or non-endemic flora better adapted to lower rainfall conditions may be an option.

Sixteen mammal species and 22 bird species whose distributions extended into southwestern Australian forests before European settlement have been listed as threatened at some time in Commonwealth legislation, State legislation, or action plans of Environment Australia or its predecessors. Confident assessment of the causes of conservation status is hampered by poor base-line data, few studies of putative impacts and a preponderance of circumstantial or anecdotal rather than experimental evidence. However, introduced foxes were Implicated In the current conservation status of 62% of the mammal species recognized, while 44% of them were negatively impacted by feral cats, 44% by agricultural clearing and 44% by changed fire regimes. Forestry practices were impllcated in the conservation status of only one mammal species. For the bird species recognized, changed fire regimes had the greatest negative impact (45% affected), agricultural clearing affected 41%, draining of wetlands affected 32% and grazing by livestock affected 22%. Forestry practices were not directly implicated in the conservation status of any bird species. While these results suggest that forestry has had minimal direct impact on the mammals and birds of the forests, the conclusion should be treated cautiously because of the poor data. While awaiting a rigorous evaluation, we argue for a strong precautionary approach to forestry in the region. With proper forest management and sound sylvicultural [sic] treatment there is no reason why there should not be built up on the wreckage of the once splendid forests of Western Australia tended forests which will yield for all time 100 cubic feet of timber per acre per year. Lane-Poole (1920). There are many reasons why Australian environmentalists would like to end logging in native forests. The preservation of wilderness, aesthetics, an almost religious identification with old growth forests and the conservation of forest wildlife figure importantly in environmental efforts to restrict logging. Wilderness and a personal identification with trees and undisturbed forests are fundamentally incompatible with logging. Recher (1996).

There is little evidence in the literature for past or current negative impacts of forestry practices on the mammals and birds of the south-west forests of Western Australia, although there are few relevant, detailed studies. For the conclusion of no major negative impact of forestry practices to be accepted, it must be shown that there are no indirect connections between forestry practices and established causes of fauna decline and that it is unlikely that forestry practices will have delayed impacts on the conservation status of mammals and birds. This paper reviews the literature relevant to these issues and concludes: (i) past forestry practices are linked to the changed fire regimes implicated in the decline of several species, indirectly connecting forestry practices with an established cause of fauna decline, (ii) there are plausible links between forestry and long-term causes of fauna decline that have not been investigated thoroughly. However, these findings need not mean that a native timber industry is incompatible with conservation in the south-west forests. Rather, they highlight the need for mediation between parties in the forest management debate, perhaps using some of the approaches developed recently in eastern Australia and North America. Concurrently, research effort could be directed towards determining the effectiveness of management initiatives already in place to ameliorate forestry impacts, while identifying actions successful elsewhere and setting research priorities to enable their effective implementation in the south-west. Forest managers, past and present, have good reason to be proud of their efforts. Even during earlier eras, when the focus of forest management was largely on timber supply, the need to ensure successful regeneration after logging has acted to conserve the whole jarrah and karri forest ecosystem. Abbott and Christensen (1994). The challenges posed by old growth eucalypt forest management in Australia are unique and by virtue of historical events, lie with our generation. To our advantage is an appreciation of what reforms are required, the availability of adequate knowledge and technology, and an understanding of what is at stake. A move towards ecologically sustainable forest use in Australia's remaining eucalypt forests requires a combination of initiatives including an enhanced conservation reserve network, and markedly enhanced protective measures in unreserved forest ecosystems, irrespective of land tenure. Significant reductions in logging quotas and major changes to current codes of forest practice are required if stated biodiversity conservation goals are to be achieved. Institutional reforms are required to support these changes as is support for long-term ecological research and monitoring. Norton (1996).