A Late Pleistocene vegetation history from the Australian semi-arid zone

Abstract

Cuddie Springs is an ephemeral lake in central northern New South Wales, Australia. The upper 3 m of sediment consist of lacustrine clays containing a Late Pleistocene sequence of extinct and extant fauna, and in the upper 1.7 m, an associated archaeological record. Changes observed in the pollen sequence include: (i) a peak in charcoal values corresponding to a dramatic decline in Casuarina woodland to chenopod shrubland at 2.5 m, respresenting a climatic shift to more arid conditions; (ii) chenopod shrubland moved into decline with the spread of grasslands around 1.7 m, and the amelioration in climatic conditions persisted until approximately 28,000 BP. A regime emerged which resulted in extended lake dry periods and peak aridity by approximately 19,000 BP and (iii) at 1 m depth, around 19,000 BP a shift to peak arid conditions is observed with a return of Chenopodiaceae and a decline in grasses. The lake entered an ephemeral phase that has persisted until the present day. The broad palaeoenvironmental framework of lake history, climate and vegetation change spans the archaeological and faunal records from Cuddie Springs. The direct association enables a closer examination of causation in faunal extinctions and human subsistence activities in the Australian arid zone.