Activities of the Centre for Palynology and Palaeoecology, 2003
The Centre for Palynology and Palaeoecology holds Sporopollenin seminars most Fridays at 1pm. Please contact Cassandra Rowe Crowe@student1.monash.edu.au if you are interested in receiving seminar notices.
Current programmes include reconstruction of the vegetation and environments of the northern Australia/Indonesia region, largely from marine core evidence, reconstruction of Quaternary environments on the basaltic western plains of Victoria and the Atherton Tableland, the relationship between sea level and human occupation in northeastern Australia, vegetation variation in forests and at high altitudes within the Southeastern Highlands, and the history of river catchments through analysis of billabong sedimants.
Marine records produced by Dr Sander van der Kaars extending through the last 100,000 to 500,000 within the Maritime Continent region are revealing marked changes in the distribution and composition of rainforest, savanna and arid vegetation in relation to global ice volume and monsoon forcing, and an overall trend to more open canopied vegetation and alteration in fire activity as a result of drier climatic conditions. A similar vegetation trend is evident in northeastern Australia but here ENSO variability rather than a waning monsoon appears to be critical influence. There is also evidence, from a combination of altered fire regimes and sustained vegetation change for major human impact regionally, dating from about 45,000 years BP and possibly from about 130,000years BP. Decoupling the relative importance of people and climate on vegetation change, and elucidation of detailed patterns of ENSO variation from the site of Lynchs Crater, are major aims of the PhD project of Sue Rule, supported by an ARC Discovery grant recently awarded to Raphael Wust of JCU and Peter Kershaw.
Large chunks of the Quaternary vegetation history of the Western Plains of Victoria are being revealed from the study of old volcanic craters. Dr Barbara Wagstaff has almost completed analysis of two overlapping pollen sequences that extend from about 1.3 to 0.7 million years ago and show marked vegetation responses to changing orbital forcing around the Early-Mid Pleistocene boundary. These changes include more marked vegetation variation with the development of existing, distinctive cool temperate rainforest, the possible loss from the region of araucarian forest remnants, and a decline in Callitris dominated communities. An older sequence, dating to the base of the Quaternary and being analysed by PhD student Kale Sniderman, shows marked cyclical alternation between rainforest and sclerophyll vegetation that appears to be controlled by precession rather than forcing from the northern hemisphere ice sheets. The rainforest was diverse and shows very late survival of almost all taxa that characterised the mid to late Tertiary period in southeastern Australia. In the more recent past, PhD student Rochelle Johnston is finalising her high resolution palynological study on the Pleistocene/Holocene transition at Tower Hill designed to examine vegetation responses to rapid climate change. This site together with similar high resolution and well dated transition studies of Lynchs Crater, and Rawa Danau in Java, are being compared to examine the regional nature of transition events and their degree of synchroneity with the well established pattern, that includes the Younger Dryas, in the northern hemisphere. A high resolution pollen record from Lake Surprise in far western Victoria covering the whole of the last 18,000 years, is being prepared by PhD student Chris White with support from an ARC Linkage grant to Peter Kershaw and archaeologist Heather Builth. The major aim of this project is to provide a regional environmental record for assessment of Aboriginal occupation and impact, and particularly shed light on the timing of proposed intensification of occupation associated with the development eel aquiculture. A link between the sub-humid plains and semi-arid environments, especially Lake Mungo, is being provided by a PhD study of the history of the lunette lake system of Bolac by Ellyn Cook. She is complementing pollen with analysis of other palynomorphs, regularly encountered but seldom acknowledged, in pollen samples.
Archaeological applications are prominent in coastal studies within northeastern Australia where Dr John Grindrod is examining swamp histories within the Whitsunday Islands and on Cape York Peninsula, and PhD student Cassie Rowe is undertaking a vegetation and fire history of Torres Strait Islands to contribute to a major archaeological study of these islands by members of the Schools fledgling Indigenous archaeology programme, supported by an ARC Discovery grant. Further from the coast, research student Nick Dolby, is addressing Aboriginal wood use and vegetation change from charcoal identified in the oldest archaeological site on Cape York, excavated by Dr Bruno David.
Caledonia Fen, in the Snowy Ranges, provides a major focus of research in the southeastern highlands. Dr Merna McKenzie, is celebrating her 80 th year by completing a high resolution pollen record that extends through the whole of the last glacial cycle. This record provides some interesting insights into normal conditions in the highlands that are very different to those of today. Details of the stability of this environment are being provided by PhD student Jonathan Brown through physical analysis, mineral magnetism and OSL dating of catchment and lake sediments. In the mountain ash forests, PhD student Alex McLeod is modelling vegetation-fire relationships with a historical perspective provided by the identification and dating of soil charcoal. PhD student Cecilia Elwood is attempting to reconstruct the vegetation and climate history of the Tasmanian highlands at a scale comparable with ecological monitoring through the dendrochronology of Arthrotaxus combined with high resolution pollen and charcoal analysis of lake sediments.
A number of existing sites of palaeoecological investigation have been utilised for palaeoclimatic reconstruction using fossil beetle assemblages. PhD student Nick Porch has applied an extensive data base he has built up on present day ranges of Australian beetles to refinement of past temperatures that have been difficult to derive from other proxy data.
Palaeolimnological studies have been concentrated on the study of diatoms in billabong sediments to document changes in stream water quality and variability through the last few thousand and particularly the last 1000 years. The Murray Basin has been a central focus although expertise has largely moved to the Department of Geography and Environmental Studies at the University of Adelaide. However, we are still involved in providing broader catchment information from pollen data. In a separate palaeolimnological study of the Yarra River, PhD student Paul Leahy has documented the pre-contact state of the river and the degree and causes of change within this system subsequent to the arrival of Europeans through analysis of three billabongs. The results suggest that the presumed natural state of the river needs to be reconsidered, and hopefully this information will be revealed if the acquisition of a job with the Victorian Environmental Protection Authority does not prevent him completing his thesis in the near future. Nerida Bleakley has completed her thesis on a sediment based study of the diatoms and chemistry of a Fjord system in Antarctica that provides some insights into the complexity of a lake-marine-ice system, and a detailed climate record for the last 4000 years.