Mammals of Particular Conservation Concern in the Western Division of New South Wales
C. R. Dickman1, R. L. Pressey2, L. Lim3, H. E. Parnaby4
1School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia
2New South Wales National Parks and Wildlife Service, PO Box 1967, Hurstville, NSW 2220, Australia
3Countrywide Ecological Service, PO Box 188, Cremorne, NSW 2090, Australia
4The Australian Museum, PO Box A285, Sydney South, NSW 2000, Australia
The Western Division of New South Wales is an administrative region of 325 000 km2: on the eastern fringe of the Australian arid zone. Since European settlement in 1788, 71 species of native mammals have been recorded in the Division, seven more have been documented only as subfossils, and a further 15 species occur within 100 km of the Divisional boundary. At least 27 of the original species have become regionally extinct, and a further 11 have declined in distribution. As in other regions of Australia, species losses have been greatest for rodents and marsupials in a critical weight range of 35-5500 g, and least for bats. However, percentage losses among the terrestrial fauna are high relative to other regions, and probably reflect both the early settlement of New South Wales and the marginal distribution in the Division of 49% of the original fauna. Feral cats are implicated in the regional extinction of up to ten species of native mammals prior to 1857. Subsequent extinctions and range reductions are attributed to combinations of causes, including predation from cats Felis catus and red foxes Vulpes vulpes, competition and habitat degradation from rabbits Oryctolagus cuniculus, stock and other introduced herbivores, clearing of trees, changes in fire regimes and human persecution.
We identified 28 species of particular conservation contern in the Division based on low abundance, distribution or survival prognosis. Nine species are of national significance, four of state, and 15 of regional, significance. The major current threats to these species are from grazing by stock, interference from feral mammals and clearing. Further land reservation is an important conservation measure, but must be complemented by more effective management of non-reserved land and by broad-scale management of feral species and other threatening processes if the current species diversity is to be maintained. Long-term fauna surveys should be initiated throughout the Western Division to provide feedback on the effectiveness of management measures, and species reintroductions should be considered in situations where threats have been removed