Constructing a comparative reference collection of phytoliths from north Queensland vegetation

A project undertaken at the Aboriginal Environments Research Centre, University of Queensland, and supervised by Lynley Wallis

Phytoliths (literally 'plant-stones') are microscopic particles of silica produced in living plant cells.When the plant dies, any phytoliths present are incorporated into the sediment profile, where they can survive for many 1000s of years. While they do not offer the taxonomic resolution of pollen, many phytoliths are diagnostic of family or genus level, and in some specific cases, species level. This makes them a powerful tool for reconstructing past vegetation patterns, and by proxy, climatic conditions , especially in areas such as northern Australia where pollen is not often preserved. However, reference collections of Australian phytoliths are, for the most part, non-existant. This project will begin the task of systematically constructing a comparative modern reference collection of phytoliths produced by plants of the north QLD savannah, as well as carrying out some experimental research into phytolith production patterns of grasses.

This project aims to:

  1. Examine phytolith production patterns within a sub-sample of the flora of the semi-arid savannah region of north QLD. Results will form the basis of a comparative collection of modern phytoliths, that can then be used to help reconstruct palaeovegetation patterns based on phytolith assemblages recovered from archaeological and other palaeoenvironmental sites. This comparative collection will be made available to other researchers and the public via the internet; and
  2. grow spinifex grasses (Triodia spp.) under controlled conditions so as to systematically assess phytolith accumulation patterns through time and the impact of silica and water availability on phytolith formation. This is important for improving our baseline knowledge about the causalities of phytolith production in modern plants, and therefore our ability to accurately interpret the patterns observed in assemblages of ancient phytoliths.

 

 

Figure 1. DAC rep Hazel Windsor collecting samples from Terminalia hadleyana

 

Figure 2. Preparing plant samples for phytolith extraction

 

Figure 3. PhD student Lincoln Steinberger examining phytoliths