RESEARCH: Preliminary Evidence for Pollen as an Indicator of Recent Floodplain Accumulation Rates and Vegetation Changes: The Barmah-Millewa Forest, SE Australia.
/ Preliminary analysis of pollen in three shallow sediment cores demonstrates that pollen is preserved in the seasonally dry, vertically accreting Barmah-Millewa Forest floodplain of the Murray River, SE Australia. Deposition characteristics of a floodplain are a critical component of catchment sediment budgets, but it has proven difficult to identify this important stratigraphic point in floodplains using radionuclide dating techniques. Pollen in a floodplain, as opposed to that preserved in lacustrine settings, provides opportunities for investigating the impact of European land-use on both sediment deposition and floodplain vegetation. Pollen from exotic plant taxa identified in floodplain sediments provided a chronostratigraphic marker for the boundary between pre- and post-European sediments in the Murray River floodplain. A maximum deposition rate of about 80 mm per 100 years is estimated from the sediment history. The pollen record shows vegetation changes within the forest since European settlement. These included changes in the density of the Eucalyptus forest; and in the composition of understorey herbs, sedges, and grasslands. Pollen concentration and charcoal and organic content also exhibit post-European changes. Thus, pollen analysis provides a technique for determining changes in sediment budgets and identifying major vegetation changes in floodplains.KEY WORDS: Pollen; Floodplain; Vegetation; Deposition; Budget; Sediment; Australia; Firehttp://link.springer-ny.com/link/service/journals/00267/bibs/24n3p359.html
Kenyon
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Department of Geography and Environmental Studies, University of Melbourne, Parkville, Australia, 3052
Rutherfurd
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