Palynological analyses of Australian surface soils and their potential in forensic science

Pollen/spore assemblages represented in surface soils, supporting a range of different vegetational community types and from various localities within Queensland, Australia, were analysed. To test the variability within surface soils from individual locations, replicate samples were taken and shown to contain similar pollen/spore assemblages. Seasonal samplings provided varying frequencies of particular pollen/spore types that were sometimes correlated with flowering of corresponding parent plant taxa. Sampling from a range of communities revealed that pollen/spore types discriminated vegetational communities. Results indicated that specific palynomorph types may be utilized as indicators of the communities within which they were found. Chenopod pollen types were found to reflect drier habitats while higher frequencies of fern and moss spores indicated more humid habitats. Fungal spores were found to also discriminate between community types. Carbon isotope signatures of some vegetational community types resulted in less negative ratios for C-4 plant-dominated communities and more negative ratios for C-3 plant-dominated communities. Ratios were also more negative for communities with greater water availability. Thus, palynology combined with carbon isotope analyses is shown to be potentially useful in forensic science in Queensland through soil sample comparisons between soil-bearing items associated with an investigation, and soils associated with the vegetation at the scene of the crime. it is suggested a database of pollen/spore types be initiated as a reference collection to be utilised for expert witness evidence in this field.