The Central West and Lachlan Catchments lie west of the Great Dividing Range in central NSW and have been subjected to extensive land clearing, grazing and agricultural pressures beginning in the 1820s. Many vertebrate species are known to have disappeared from these catchments but reliable data for species diversity, distribution, abundance and conservation status are not available. For this assessment of the diversity and status of the vertebrate fauna in these catchment areas a comprehensive database of vertebrate records was established, species distributions mapped, faunal communities determined by pattern analysis and conservation status determined at a regional level. The extent of post-European human-induced landscape change was evaluated by assessing the degree of habitat loss, loss of landscape function and resilience through changes to the water cycle, soil and energy flow and the impact of invasive species, diseases and agricultural pollution.
Of the 595 vertebrate species verified for these catchments, 6% are introduced, 12% have been listed in NSW under the Threatened Species Conservation Act 1995, 4% by the Commonwealth Environment Protection and Biodiversity Conservation Act 1999, 40% are regionally vulnerable, 20% regionally endangered and 2% likely to have become extinct in the region. Overall we estimate that 64% (382) of species are declining. These statistics present a grim picture of the survival of vertebrates in these catchments and potentially for the sheep-wheat belt of eastern Australia. The extreme loss of habitat and its poor condition across much of these catchments followed by serious changes to the functioning of the landscape provide clear reasons for the catastrophic decline of vertebrates in this landscape. If this serious decline in the Central West and Lachlan catchments is to be halted, strategies aimed at habitat and landscape restoration must be developed. Current strategies based on Threatened Species management plans and ad hoc planting for revegetation have not produced results. We need a radical rethink.