Holocene Forest and Wetland Vegetation Dynamics at Barrington Tops, New South Wales

Abstract

Pollen analyses from eight sites and fifty-seven radiocarbon analyses from nine sites are described to give a vegetation history and chronology across the Barrington Tops Plateau. It is shown that sites record local plant community history, and that between-site comparisons enable identification of vegetation change across the Plateau. At present, the area above 1000 m supports a mosaic of sub-alpine grasslands, montane eucalypt forests, wet eucalypt formations, cool-temperate rainforests and wetland communities. By 9000 BP these had all been well established but there have been changes in the contributions of each vegetation type to the mosaic. In the period from 6500 to 3500 BP, cool temperate rainforest covered a larger area of the Plateau in the east, while wet eucalypt forests were more extensive in the west than at the present. This could have resulted from an increase in temperature and in summer rain-bearing winds from the south and east. Retreat of these forest types began around 5000 BP and by 1600 BP large areas on the west were replaced by montane eucalypts with a sub-alpine grassland understorey. Some expansion of cool-temperate rainforest began in the same region from about 1500 BP, although this was mainly restricted to sheltered localities. In the wetland areas there was a general trend from open water with aquatics to higher productivity with sedges and Sphagnum-forming hummock/hollow communities around 3500 BP. Peat formation then became widespread and expanded within the last few centuries when further wetland areas became established, particularly in the Gloucester Tops