Preservation quality of plant macrofossils through a Quaternary cave sediment sequence at Naracoorte, South Australia: Implications for vegetation reconstruction

Abstract

Plant macrofossils are an important source for detailed vegetation reconstructions, often at the species level, which usually cannot be achieved with other plant material such as pollen and spores. However, the preservation quality of plant macrofossils is not well understood, especially in cave settings. Here, we assess the preservation quality of Quaternary plant macrofossils of Casuarinaceae, Astroloma humifusum, Banksia marginata and Eucalyptus species for Robertson Cave, in the World Heritage listed Naracoorte Caves. We conclude that the level of preservation varies considerably among taxa and plant organs, which can influence the vegetation reconstruction. Woody endocarps and fruits preserved better as macrofossils than leaves and flowers. The age of the sediment did not always impact the preservation quality, although in some cases it led to clear deterioration. The impact of fire was evident and possibly influenced the preservation potential of some taxa. Therefore, care must be taken when reconstructing vegetation from plant macrofossils as preservational changes and floristic change are sometimes difficult to separate.