Preliminary results from tree increment and playa sediment cores from the Paroo, north-western New South Wales, Australia

Abstract

The Paroo ecosystem of far north-west New South Wales is sensitive to ENSO. The Paroo is also currently subject to contention for water extraction (Aquat. conserva.: Mar. Freshwater Ecosystems 8 (1998) 361) in which information about long-term ecosystem dynamics may be useful. The environmental history of the Paroo has not been described, despite the existence of potential records in saline lakes, dunes and Callitris trees. Geomorphic and pollen analyses are used to determine the duration and nature of the pollen record in both lake and dune deposits. A 2 m core recovered from one unnamed lake (informally named Palaeolake) and the slow accumulation of sediment (ca. 175 years cm −1) shows the record may cover 38 K years. Discontinuities in the lake sediments are expected to be less than the larger southern salinas and the gaps will be partly recorded in the dune materials. In tandem, the tree rings from two stands of Callitris glaucophylla have been tested to determine the high resolution dendroclimatological record available. Ring width patterns were matched between trees using skeleton plots. The temporal variability of these patterns and the uniform response of the trees indicates that ring width geometry is dependant upon climate. Preliminary results for organic material, mineral magnetic susceptibility and stratigraphy of the playa and dune facies promise a good record of Pleistocene climatic change. The results show that the lake records give long but temporally discontinuous information whereas tree rings provide short and relatively continuous information. Together they record climate changes over the last few thousand years and the impact of European management on the vegetation and rates of sediment deposition.