Résumé
The study of arid palaeoenvironments is often frustrated by the poor or
non-existent preservation of plant and animal material, yet these
environments are of considerable environmental importance. The analysis of
pollen and macrofossils isolated from herbivore middens has been an
invaluable source of information regarding past environments and the
nature of ecological fluctuations within arid zones. The application of
ancient DNA (aDNA) techniques to hot, arid zone middens remains
unexplored. This paper attempts to retrieve and characterise aDNA from
four Southern Hemisphere fossil middens; three located in hot, arid
regions of Australia and one sample from South Africa’s Western Cape
province. The middens are dated to between 30,490 (±380) and 710 (±70) cal
yr BP. The Brockman Ridge midden in this study is potentially the oldest
sample from which aDNA has been successfully extracted in Australia. The
application of high-throughput sequencing approaches to profile the biotic
remains preserved in midden material has not been attempted to date and
this study clearly demonstrates the potential of such a methodology. In
addition to the taxa previously detected via macrofossil and palynological
analyses, aDNA analysis indentified unreported plant and animal taxa, some
of which are locally extinct or endemic. The survival and preservation of
DNA in hot, arid environments is a complex and poorly understood process
that is both sporadic and rare, but the survival of DNA through
desiccation may be important. Herbivore middens now present an important
source of material for DNA metabarcoding studies of hot, arid
palaeoenvironments and can potentially be used to analyse middens in these
environments throughout Australia, Africa, the Americas and the Middle
East.