The Holocene History of the Vegetation and the Environment of Jibbon Swamp, Royal National Park, New South Wales

Abstract

Jibbon Swamp, in the north eastern part of Royal National Park, yielded a sedimentary history of 8,000 years. The present vegetation was mapped and the modern pollen deposition studied in order to assist interpretation. The palynology infers little change in the vegetation, other than a shifting mosaic of sclerophyllous communities similar to those seen in the area today.The nature of the accumulating sediments and their algal and fungal spore content can be interpreted to reflect the hydrological history of the swamp. An initial establishment period of 8,000 to 5,500 year ago was followed by a permanent pool of water too deep for the sedgeland swamp vegetation, from 5,500 to 2,400 years ago and then a vegetated swamp that dried out periodically, from 2,400 years ago to present, as it does today. Changes in the sediments and algae/fungi record suggest a wetter early Holocene and a drier mid-late Holocene climate, with an intensification of the dry periods about 2,500 years ago. This pattern of change seems to reflect regional climatic change. There is very little change in the less sensitive sclerophyllous vegetation. The likely impact of rising Holocene sea levels on this near-coastal environment is discussed.