Subfossils

A dissected Barn Owl pellet showing the contents of one nights hunting

A dissected Barn Owl pellet from the Strzelecki Desert showing the contents of one night’s hunting. This owl caught and consumed: one Dusky Hopping-mouse, one Forrest’s Mouse and a female grasshopper.

Research Overview

Since the arrival of Europeans in Australia, just over 200 years ago, there has been an extraordinary increase in the rate of environmental change and in the loss of biodiversity. This biodiversity loss has been largely caused by habitat loss due to the clearing of land by Europeans for farming. The introduction of alien species has also lead to increased predation on, and competition with, Australian native species for food and habitat. This has caused most terrestrial native animals to experience large changes and reductions in range at best, and extinction at worst. In most cases the process of habitat loss happened so quickly that the only record of pre-European faunal distributions available is the subfossil record.

The Subfossil Collection and the expertise of Honorary Research Associate, Mr Graham Medlin, of the Mammals Section are widely used by South Australian (University of South Australia, University of Adelaide and Flinders University) and interstate researchers.

Three significant subfossil deposits on Yorke Peninsula, including two old owl roosts and the third an Aboriginal midden site, have been analysed and reported on in McDowell (2012). The analysis showed that at least 25 species of small mammal existed in the area before European occupation, where currently there are only about three. This illustrates that Yorke Peninsula has been impacted by loss of mammal diversity, more than most other parts of South Australia.

All native mammal records in the subfossil database have now been included in the maps to be published on the Web in the ‘Census of South Australian Vertebrates’. This will enable modern distributions of species (small enough to be caught by owls and other birds of prey) to be compared with distribution prior to European occupation. The maps also show the distribution of extinct species which were never recorded as live animals in South Australia.

Ongoing research includes the analysis of modern Barn Owl pellets as well as fragmentary bone deposits from old owl roosts. In a few instances the known ranges of some species have been extended by the analysis of fresh pellets.

A recent collection of whole and partial skulls and thousands of post-cranial bones has been made by Museum volunteer John Light. Collected from caves in the Murray cliffs near Mypolonga, a preliminary examination of the bones has shown that the deposit contains at least eight species of rodent, six species of small marsupial, as well as bird and reptile remains. More species are likely to be identified once the deposit has been fully analysed. The presence of the remains of the, now extinct, Long-eared Mouse (Pseudomys auritus), extends its range 70 km northwards from the area around Lake Albert where the original type and paratype specimens were collected in the 1840s and 1850s. More work needs to be done to unravel the mysteries of this significant subfossil deposit which is a veritable museum of small animals once found along the River Murray before European settlement.

 

Publications

Kemper, C. M., Cooper, S. J. B., Medlin, G. C., Adams, M., Stemmer, D., Saint, K. M., McDowell, M. C., and Austin, J. J. (2011). Cryptic grey-bellied dunnart (Sminthopsis griseoventer) discovered in South Australia: genetics, morphological and subfossil analyses show the value of collecting voucher specimens. Australian Journal of Zoology 59: 127–144.

McDowell, M. C., Baynes, A., Medlin, G. C. and Prideaux, G. (2012). The impact of European colonization on the late-Holocene, non-volant mammals of Yorke Peninsula, South Australia. The Holocene 22(12): 1441–1450.

Mahoney, J. A., Smith, M. J., and Medlin, G. C. (2008). A new species of hopping-mouse, Notomys robustus sp. nov. (Rodentia: Muridae), from cave deposits in the Flinders and Davenport Ranges, South Australia. Australian Mammalogy 29: 117–135.

Mahoney, J. A., Smith, M. J., and Medlin, G. C. (2008). 'Broad-cheeked Hopping-mouse Notomys robustus'  in Van Dyck, S. and Strahan, R. (eds) The Mammals of Australia, pp.  609–611. Third edition.  Sydney: Reed New Holland.

Medlin, G. C. (2008). 'Long-eared Mouse Pseudomys auritus' in Van Dyck, S. and Strahan, R. (eds) The Mammals of Australia, pp. 615–616. Third edition.  Sydney: Reed New Holland.

McDowell, M. C. (1997). Taphonomy and palaeoenvironmental interpretation of a late Holocene deposit from Black’s Point Sinkhole, Venus Bay, SA. Proceedings of the Linnean Society of New South Wales 117: 79–95.

McDowell, M. C. and Medlin, G. C. (2009a). The effects of drought on prey selection of the barn owl (Tyto alba) in the Strzelecki Regional Reserve, north-eastern South Australia. Australian Mammalogy 31: 47–55.

McDowell, M. C. and Medlin, G. C. (2009b). Using the diet of the barn owl (Tyto alba) as an indicator of small vertebrate abundance in the Channel Country, south-western Queensland. Australian Mammalogy 31: 75–80.

McDowell, M. C. and Medlin, G. C. (2010). Natural resource management implications of the pre-European non-volant mammal fauna of the southern tip of Eyre Peninsula, South Australia. Australian Mammalogy 32: 67–93.