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Fossil pollen records from playa lakes west of the Great Anabranch of the Darling River indicate significant environmental changes have occurred in southwestern New South Wales during the Holocene (last 10,000 years). The modern semi-arid rangeland surrounding the playas bears little resemblance to the vegetation that emerged from the last glaciation. Daisy herbfields and saltbush-bluebush low shrublands dominated the region in the early Holocene. Native pine and casuarinas, probably bull-oak and belah, gradually increased in cover and by c. 5,000 years ago the region supported dense woodlands. The presence of bull-oak, now uncommon below the 380 mm annual rainfall band, indicates the climate was considerably moister than at present. Increased aridity or more frequent droughts occurred in the last 5,000 years, possibly due to climatic variability caused by the onset of ENSO-type events. Woodlands contracted, with bull-oak disappearing from the record, and saltbush and bluebush low shrublands expanded. Mallee eucalypts became common in the last few thousand years, probably because of their ability to survive drought. Native pine and belah declined after European settlement, due to clearing, timber cutting and limited regeneration.